Qubic Light's LED Projector Looks Good (http://www.insightmedia.info/news/QubicLight%92sLEDProjectorLooksGood.htm)

More microdisplay industry news here (http://www.insightmedia.info/news.html)

PS Lumileds has announced the Luxeon III, a white-light LED capable of outputting 80 lumens with a 20K-hour lifetime.

I have several flashlights that have Luxeon III bulbs in them. Basically the L3 is just a version of the 1W Luxeon that is able to be over driven. There is a significant blue tint to the Led when you over drive it.

All in all, I am a LED fanatic, so I really hope to see a decent LED based projector in the next couple of years.

With that current projector, sounds like all they need is one of Vutec's 9 gain screens :)

I would also like to see an LED projector, hopefully earlier than the next couple of years.

I don't understand why they are using white LEDs and LCOS. It seems that red, green and blue LEDs with DLP would be a perfect combination.

Dave

Yeah, RGB LED with DLP would be several times more efficient, at least. Using white LEDs and then RGB filtering cuts light by two-thirds, and polarizing cuts it further in half. RGB LEDs are ideal for sequential color displays. The duty cycling would triple the lifespan (to 150,000 hours) and allow them to run at a much lower junction temperature, which raises efficiency.

Agreed. You could have the perfect 3-chip DLP/LCOS *or* single-chip DLP using red/green/blue LEDS...you'd need no color wheel since the LEDs have such fast on/off capability...they could literally sequence RGBRGB and probably do so faster than a colorwheel. You'd also be free of the "spoke time" because the whole surface of the chip would be instantly refreshed with the new color vs the "sweep" of color you get with a mechanical colorwheel (and that sweep or spoke time is not used for normal picture content...the DMD is either turned to "off" or used for some other process to boost brightess etc.).

-dave

It has been suggested that the fast on/off time of LEDs could lead to an effective colorwheel equivalent speed of >15X. Consider the possibilities of no rainbows and perfect convergence.

Dave

Exactly. It would actually be a strong case for single-chip projectors producing *clearly* (pun intended) superior pictures to those of mutli-chip designs without interjecting any of today's single-chip artifacts into the mix.

-dave

What kind of spectral output does r g b LEDs have? It is light emitting diode? Would you rather have laser emitting diode, do they exist?

I am sure you could flash the colors on and off faster, but the time to render color will only be improved by less spoke time. How much time is spoke time 10-15 percent? You might eliminate rainbows , but surely you would have the same problem with rendering color gradations in a fast moving picture.

LEDs tend to be narrowband emitters. They have a peak wavelength, and then output falls off fairly rapidly in both directions. You would probably aim your production for a given wavelength and then select the parts that come closest. My guess is that spoke time eats up 1-2 possible cycles per second, so LED/DLP would likely be good for 6-7x equivalent. Given that 5x gets pretty close to eliminating rainbows, that might just be good enough. The other problems associated with one chip DLP are still around, though probably slightly lessened because of more mirror time per second. Probably the best aspect of a LED projector is that the LEDs will likely last the entire life of the projector. Laser diodes do exist. Laser has a lot of potential with LCOS, because it is an inherently polarized source.

Curious, why can't one just use a white LED and color-corrected filters?

Are LEDs more energy efficient than laser diodes?

Can LEDs or laser diodes be designed for a specific peak wavelength, or is this limited by materials?

There are a number of reasons that white LEDs are not good projector sources. They are expensive relative to narrowband LEDs. The phosphor wears out and so they have a shorter lifespan. They have a poor spectrum, with spikes and dips. But most of all, white LEDs blow because RGB color filtering will lose 2/3 of the light. Why generate light and then throw it away? LEDs are already a lot less efficient than discharge lamps. However, when you use narrowband sources, you get an automatic tripling of efficiency versus filtered white light. This allows LEDs to be competitive with other sources. For a given output of light, a projector using RGB LEDs will use a third the power and generate less than a third of the heat than one with white LEDs, and the source will last at least three times as long. There's just no point.

Originally posted by Andrikos

RGB LEDs with single chip DLP would be a perfect solution maybe 2-3 years out.


What improvements will take 2-3 years? Light output? Efficiency? Cost?

Would an LED-based DLP projector be equivalent in initial cost to one powered by a standard lamp?

2-3 more years for improved light output levels which are probably going to be provided by increased efficiency. Some colors are less efficient than others - red is very efficient, deep blue isn't, so the system will probably be limited by the least efficient colors.

Assuming prices remain constant or decline, the LED based DLP ought to be somewhat cheaper - the retail on the luxeons is in the $10-$30 range depending on specific characteristics.

Originally posted by Ohlson
What kind of spectral output does r g b LEDs have? It is light emitting diode? Would you rather have laser emitting diode, do they exist?
...

I think that one of the problems with LEDs is that their primary emission is far away from the color of CRT phospers (and therefore also from the NTSC/ATSC standards). I don't know the frequencies offhand, but some googling could probably find the values.

Personally I would prefer LEDs to laser diodes because the LEDs theoretically should be more efficient, run cooler, have longer lifetimes and most importantly won't suffer from the scintillation problems that have to be solved in laser systems.

I'm not hard over on this though. A good laser system could change my mind.

Luxeons are less than $2 in quantity.

Andrikos
Why are the best crts color corrected?
I guess they are to output a narrow band spectrum of the optimum wavelength.

Why have a band when you can have a peak. If you add precise amounts of precise wavelengths you have many and good colors. I am sure this is better than adding reddish , kind of blue and a sort of green.

It was commented in the article that the manufacturer said the colors were more correct. The viewer found the colors different.

Dmds have a certain speed. If you have 60 frames per second they have a fixed amount of time to render that frame. With no spoke time the dmds get more time to render the frame. Can someone give a good estimate of this added time? If it is 20 percent more time we could go to 6x color wheel for NTSC. If you want to go higher then 6x then you would have to sacrifice color rendering or increase the speed of the dmd.

DMDs cannot load data faster than LEDs can currently be switched on/off. If you were to use LEDs as a source, you would be DMD load time limited, today.

HOWEVER, this would yield amazing results right now. When the HD2+ systems added a forrest green segment, they obtained 2 more real bits of green color depth. If *I* were using an array of LEDs as a light source, I would make sure I could control the number of each color that could be turned on at any one time. I would have forrest green (<100% of the green LEDs turned on) along with dark red and dark blue time portions. This would give me the opportunity to have 10 REAL bits per color with no spoke time penalty and no dithering.

One other positive about not needing a "mechanical" color-wheel.

With instant on/off LED light sources and single-chip DMDs, one could instantly change "refresh" rate. This means that the DMD could sync to 50Hz, 60Hz, 24Hz, 72Hz, whatever and instantly switch duty cycles without any video glitch or frame-rate conversion. You could play back a montage of film/video sequences with no visible scan-rate conversion artifacting.

*finally* would could get some movie playback from DLP without that darned 3-2 judder that no manufacturer has properly addressed.

I think by the time you got ~1000 lumens to the screen, the LEDs would end up costing more than a bulb, but it's a one-time cost and not a consumable. The real problem is gathering the light from the LEDs, collimating it, and getting it to the DLP. Several companies say they've got a solution to the problem, but I'm still curious about the details.

How long before 500 lumens output? In the dark cave this and possibly less lumens should be fine. It would feel better not to have to worry about the lamp. Buying lamg reminds me of the ink jet printer market. It is better to pay and to forget.

Originally posted by scoby
The real problem is gathering the light from the LEDs, collimating it, and getting it to the DLP. Several companies say they've got a solution to the problem, but I'm still curious about the details.

Could you elaborate a little about the problems that you identified?

Dave

Search on entendue and poster Guy Kuo.

To be honest, Ohlson, I don't know when we'll see 500 lumens. It all comes down to how much light these guys can gather. Obviously, since we don't know how they're overcoming the problem of etendue, we can't even guess at what light efficiency they're seeing. So we really don't know how many LEDs are needed as a source. The basic answer is that when we know how many lumens they're seeing now and at what efficiency, then we can probably estimate when we may see decent output, using Lumiled's roadmap as a guide. Until then, though, who knows?

Ultra-Compact LED based Image Projector for Portable Applications (http://www.lumileds.com/pdfs/techpaperspres/display_p_126.pdf)

In my opinion this not very good idea: usage the transmissive LCD instead of LCOS or DMD.

Originally posted by Andrikos
dcottle,
ANYTHING is more efficient than laser diodes. LASER needs a LOT of power and cooling.



Why does everyone here think LED's are more efficient than laser diodes? According to the graduate electrical engineering class I just took, laser diodes are always more efficient than the equivalent LED.

A laser diode is just an LED with special properties: frequency is tuned to the size of the resonant cavity in the silicon, cavity has mirror surfaces, etc.

The reason an LED is more inefficient than its equivalent laser diode: most of the light never leaves the silicon, it is reabsorped and turns into heat, where as in a laser diode, almost all of the light travels in a single path out of the mirror faces.

Also, the way coherent light emission is stimulated by other photons is more efficient than the way non-coherent light just randomly "occurs" in an LED.

I'm not saying all lasers are efficient, just that an LED tuned to be a laser is more efficient than the LED.

My neighbor is a business man/ engineer with a Taiwan facility which just produced a 20 watt LED (Supposedly one of the brightest LEDs) and he says the needs of the projector just to great for the near term LED's in the pipeline. They will focus on industrial lighting where there is need in hard to get to light (i.e. high ceilings). The volume is there not in projectors. When the LEDs reach a bright enough output as driven by other market opportunities then a version can be developed for projectors.

How about LED headlights for the application?

http://www.audiworld.com/news/03/geneva/nuvolari/nuvolari08.jpg

Revolutionary: The LED headlights

LED headlights allow the designer more freedom, since they need less installation space than conventional ones. The cooled high-end lights, 18 on each side, are located much nearer the surface of the cover, which has also been reduced in size, so that the entire front end or the car is more harmonious in its styling.

LED – these three letters not only signify progress for the designers but also offer solid advantages such as longer life and energy consumption ten times lower than that of conventional bulbs.

As if this were not enough, LED technology offers further future potential. In a future development stage, LED headlights will make dynamic cornering beams possible without the need for movable parts in the system. The width and direction of the beam can be specifically adjusted by activating more light elements electronically.

QubicLight home page (http://qubiclight.com/)

Less than $1,000 retail. I wonder what panel technology they will use.

Originally posted by Alan Gouger
Less than $1,000 retail. I wonder what panel technology they will use.

Prototype was powered by a single SXGA resolution LCOS panel from MicroVue.

Can someone provide some resources for single-panel LCoS technologies? I am more than a little curious on this aspect of LCoS.

I have a few questions.

Let us assume r,g.b LEDs since this is what we are talking about.

If a singel chip lcos panel is used it will have to be a quick one to get rid of rainbows. Let us assume a 600Hz cycling frequency.

sxrd at 5ms not fast enough , medium high cr
Philips lcos at 1ms is fast enough, low cr
but the LEDs can be turned off so we can reporduce black

A theoretical projector
600Hz rgb cycling
r,g,b LEDs and light output at 200 ANSI lumen
600:1 cr lcos panel analog modulation, but wait a minute can we adjust the intensity of the r.g. b LEDs?
1280x720

Philips already has a one-panel LCOS RPTV. No reason it couldn't be adapted.

Intel's LCOS designed are apparently focused on single-chip applications, too.

Yeah, that's what we've said and heard about 1080P technologies being deployed in RPTV's, too. Unfortunately I am one of those anomalies with the 'seeing is believing' philosophies. :)

The one panel LCOS's on the market right now have horrible rainbows. The MicroVue is actually a faster LCoS chip that behaves much like a DMD in a pulse-width modulation manner.

It isn't quite as fast as the DLP from my understanding but it would be fast enough.

The light spectrum WILL be sequential RGB LED's. White LEDs will not be used. The only thing that makes it viable is that you can operate LEDs in burst mode at 3 times their normal output at a dutycycle of 33%.

But even with that clever form of illumination, it appears that the LED still aren't bright enough to deliver a bright image. My guess is we are talking about 50 lumens for his prototype and the production are going to have similar issues whenever they are released.

However, I've said it a million times that LED light once it is efficient enough is going to work really really well.

-Mr. Wigggles

MrWigggles
How do you see the future LEDs versus solid state diode pumped lasers?

I have asked before and I do so again, does anybody know the lumes per watt ratio for
ssdp lasers
LEDs
UHP lamps
Xenon lamps

Originally posted by MrWigggles
My guess is we are talking about 50 lumens for his prototype and the production are going to have similar issues whenever they are released.

However, I've said it a million times that LED light once it is efficient enough is going to work really really well.

-Mr. Wigggles

50 lumens? That seems to suggest that a 10 to 20-fold improvement in LED light output would be necessary for front projection. Is this realistically achievable?

Dave

Originally posted by dcottle
50 lumens? That seems to suggest that a 10 to 20-fold improvement in LED light output would be necessary for front projection. Is this realistically achievable?

Dave

From the prototype presentation:

The LED-based front projector illuminated a 50-inch screen in the demonstration given by Michael Burney, the CEO at Qubic Light. The projector itself was in a not-sized-optimized enclosure that measured 9 x 8 x 3.5 inches. The room was dark and the image was not bright, but it was not dim either. Burney declined to specify the lumen output, so you can assume it was low, but will only get better, of course.

You would need 4 times the light energy to produce the same image on a 100" diagonal screen. Given that the screen material wasn't given (some gain I'm sure) and the remarks that it wasn't bright, and didn't have colors quite rights leads me to believe D65 (i.e. ~6500K) lumens were in the neighborhood of 50.

I think that production models will be 200 lumens which will work for HT if you design your theater correctly - modest size screen and HIGH gain. (Silverstar and Hi-power come to mind)

People need to remember that in a normal DLP, a 250 Watt UHP lamp will put 5000+ lumens through the input aperture and yet you'll be lucky for 1000 to come out. Now 2/3 rds of that light is lost by the colorwheel which for the most part won't happen with a LED based light source (however light will have to be combined through an x-block which is not lossless.

A well designed LED projector with today's LED's might get close 200 D65 lumens but it will 3+ years before by my fearless estimate that we will see something in the 800+ lumen range.

-Mr. Wigggles

If they can manage to do 300 lm for $1000, I'd be willing to buy 3 PJs and stack them. :) ;)

I have 2 LED light bulbs. 20 white LEDs per bulb.
They rate these the same brightness as a 100 watt incandescent bulb but they only drain 4 watts.

They are not very bright at all as far as giving off ambient light and lighting up a room but if you look directly at these your blinded for some time. Way brighter then looking directly at a 100 watt bulb. I they can capture and focus the hot spot of each LED I can see where they would be bright enough.

The problem with LED's isn't that they aren't efficient. The problem is that they are bulky and that makes focusing the light much more difficult (unless you use a huge imager)

-Mr. Wigggles

Hey all,

I know there have been a few LED projector threads, but this seems to be the most recent.

Just stumbled onto NEC's patent, obtained in Nov of 2003, for a LED-based DMD projector: Patent 6644814 (http://patimg1.uspto.gov/.piw?docid=US006644814&SectionNum=1&IDKey=3DF33A6FC51A&HomeUrl=http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2%2526Sect2=HITOFF%2526u=/netahtml/search-adv.htm%2526r=9%2526f=G%2526l=50%2526d=PTXT%2526p=1%2526S1=( NEC.ASNM.%252BAND%252Bprojector)%2526OS=AN/NEC%252BAND%252Bprojector%2526RS=(AN/NEC%252BAND%252Bprojector))

It uses "fly eye" lenses and a dichroic prism to control and combine the arrays of R,G, and B light sources.

[ Edit: The link may not always work, so here are two other ways of getting there: Another Search resolve link (http://patft.uspto.gov/netacgi/nph-Parser?TERM1=6644814&Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2Fsrchnum.htm&r=0&f=S&l=50) or Enter 6644814 here (http://patft.uspto.gov/netahtml/srchnum.htm) ]

DocDvd has tested a LED RGB panel projector. He said its not quit ready for prime time ( not very bright) but the contrast ratio was excellent because like a CRT the LEDs are on or off.

I have many LED flashlights. Currently my brightest one has 3 5 watt Luxeon Star LED's fitting in a mag light head. It runs on 6 D cell batteries for 10 hours or more. The flashlight puts out in excess of 300 lumens in a blinding focused beam. If I shine it at my screen with my projector on, it almost completely overwhelms the image.

It is not a question of if LED's can be used effectively in a projector, but when it will happen. With the advancements in the technology, I believe that this will be the future.

Alan G.
I guess you mean that LEDs can be anything from off to full current on. In that sense they should provide for adjusting the light output. The important point in your mind must be that they can be totally off or?

Sunnybrook works on high dynamic range (HDR) displays. They mention leds at 250000 cd per square meter!! They work on displays that can show daylight close to what it is 10000 cd per square meter. They work on a display with led backlighting and an lcd in front. The leds adjust light level on lower spatial frequency and the lcd displays the high spatial frequency information.

That NEC patent is fascinating.

What is also fascinating is that Luxeon published a white paper describing how to use LEDs in a projector about the same time as the NEC patent was filed. (maybe some prior art issues?)

Anyway, the NEC device still uses A LOT O' glass to obtain its goal which means it ain't going to be cheap to impliment. I count 19+ (probably ~25)lens in the design.

But the benefits of LED's if you can get the brightness high enough are staggering. I walk into Best Buy on occasion and the Samsung DLP's are always some of the dimmest displays shown. They don't start out that way but they always end up that way (yes, the bulbs are on a lot but so are the CRT projectors that are right next to them)

No moving parts and 100,000 or so runtime life? I would never turn my projector off. It would also probably only be 120 watts of total dissipation.

The possibilities are incredible, they just need to get the lumens up.

-Mr. Wigggles

Ps. edit: here is a link to the 10/27/2002 SID presentation about Luxeons in projectors. http://www.lumileds.com/pdfs/techpaperspres/SID-BA-Paolini.PDF. I can not find the whitepaper about this though. I don't know too much about the patent process to know if this constitutes prior art or how it would impact other projector manufacturers from developing their own LED projectors (i.e how easy would it be to circumvent NEC's claims since idea as a whole wasn't new when they filed)

Mr Wiggles (geez thats too weird to type in a serious thought...)

I think assembly twelve is a typical projector optical assembly. And based on the patents I've looked at for other companies (InFocus, RCA, NEC, etc) the part count is normal. Hopefully, optics wouldn't drive the price through the roof.

That said, a previous thread pointed out that LED-based projectors could use plastic lenses since LED light lacks the IR/UV components.

Oh and anyone else guessing a major marketing point would be; "No fragile bulb to break when you carry it between meetings!" The optics would become the most delicate part. NEC makes a lot of business projectors, don't they?

Happy patent hunting

Davandron,

You are correct the light for optics before the imager can be plastic for the reasons you mentioned, but those after the imager I think still will need to be glass.

It will definitely be simpler than current LCD projectors but at least a little more complicated than current 1-chip DLP projectors.

The advantages are huge if they can get the light output up. (even if they can't it will still be nice for high gain screens etc.)

-Mr. Wigggles

The neat thing about getting the output up from an LED is that as lpw goes up, the junction temperature goes down. That means you can pack more devices into the same square area, which improves the amount of light you can get through the optical system. Osram and Lumileds have both demonstrated red LEDs with output of more 100 lpw. I'd be curious to know just how efficient NEC's optics are.

Even the best coated glass is only 99% efficient at the boundaries where air meets glass (there are some internal losses as well). A more conservative number is about 97% (meaning 3% of the light is reflected back at each boundary.)

A 10% efficient DLP projector is pretty good when it is all said and done with conventional color wheels etc. Lumileds said that they should be able to get 36% effecient DLP in the PDF above.

The key element is green LEDs. The Red LEDs are plenty bright at this point. It is the Green that are going to need some further devlopement. The way lumens work is that you need about 3X the Green lumens as you need Red and about 3X the Red lumens as you need blue.

So hopefully a 5 Watt Red LED, 20 Watts of Green LEDs, and about 20 Watts of Blues would be all we need for 1000 lumen projector. Put in another 50 Watts for all the processing we could want and we are at about 100 Watts total.

Hopefully.

-Mr. Wigggles

Agfa has been using the exact same technology on there Hi speed photographic printer for 6 years. it is used to print index prints, and it does work very good and is reliable. here is the link. Dale

http://www.agfa.com/photo/products/labequipment/wsf/msp_dimax/index_print_systems

Originally posted by MrWigggles
The key element is green LEDs. The Red LEDs are plenty bright at this point. It is the Green that are going to need some further devlopement. The way lumens work is that you need about 3X the Green lumens as you need Red and about 3X the Red lumens as you need blue.

So hopefully a 5 Watt Red LED, 20 Watts of Green LEDs, and about 20 Watts of Blues would be all we need for 1000 lumen projector. Put in another 50 Watts for all the processing we could want and we are at about 100 Watts total.

Wiggles,

When you talk about lumens of red/green/blue, you're referring to the human/eye response, right?

As I understood it, sensitivity went from Red at the lowest, to Blue at the highest. But perhaps you are adjusting for the very high efficiency red LEDs, and talking about power consumption not output when you talk about watts?

Here (http://www.photo.net/photo/edscott/vis00010.htm) is some info on the human eye and color theory for everyone's advantage.

What are NEC's likely business plans?

It seems that most new DLP technology ends up in RPTVs first. Will NEC follow this path, or will they move into front projection? Light output may already be in the ballpark for RPTVs, and if NEC combined LEDs with TI's xHD3 chip I think they could have a very high performance product.

Any guesses as to what this could sell for?

Dave

Originally posted by Davandron
Wiggles,

When you talk about lumens of red/green/blue, you're referring to the human/eye response, right?

As I understood it, sensitivity went from Red at the lowest, to Blue at the highest. But perhaps you are adjusting for the very high efficiency red LEDs, and talking about power consumption not output when you talk about watts?

Here (http://www.photo.net/photo/edscott/vis00010.htm) is some info on the human eye and color theory for everyone's advantage.

We as humans are senstive to green, red and then blue in that order.

When I talk about Watts it is in reference to the Watts going to the LEDs not the radiometric output of the LEDs.

Lumens are not radiometric (i.e. not Watts) they are based on the humans ability to detect output. Humans are much more senstive to green than they are red and even more to green vs. blue.

lumens are based on this physiology. Blue in ANY projector is almost always putting out more actual Watts than red or green.

-Mr. Wigggles

Wigggles, even the bright DLPs like the Infocus 7200 are about 8% efficient (200w UHP @ 60lpw = 12,000 lumens). Something like a Sharp 12K appears to be about 6%. And that is starting with a really small arc. It's hard to tell from NEC's patent if they've solved the etendue problem, but I think LED projectors will need a lot more light that you're supposing. I don't foresee LEDs outshining discharge projectors for as long time to come at equivalent power levels. The main advantage will be the elimination of the color wheel, so the RGB sequence can be sped up, and fractionally more mirror time for less dithering. In addition, the sources will likely last the life of the projector. The real difficulty will be keeping the LEDs cool, as life and output decline drastically with junction temperature. Packaged LEDs like the Luxeons are not the answer, as they have a relatively high thermal resistivity.

scoby,

One of the key benefits of LED is that you can run them in burst mode for a single chip design.

When I say a 5 Watt red LED, what I really mean is a 5 Watt red LED run at 15 Watts 1/3rd of the time.

This is where Lumileds 36% efficiency claim comes from. You don't scrub 67+% of your light with a colorwheel like you do with a LAMP based design.

I said "hopefully" because I don't know how accurate Lumiled's numbers are simply that I understand where they are coming from.

-Mr. Wigggles

EDIT: Ohlson, yes I meant lamp.

MrW
You mean ___ like you do with a lamp based design. ?

If LEDs have a lower lumens per watt and are bigger than the arc of a traditionla lamp why are they so promising? We want delivery in two years and not in twenty years.

For everyone's enjoyment, here is a technical summary of some of LEDs advantages, a few of which we've been talking about:

1. Direct control of the light source
1a. "No Color Wheel:" The color wheel currently absorbs a significant amount of light to enable the system to be controlled. It presents an inefficiency that LEDs will not have to overcome

1b. "No more rainbows:" Since the colors can be cycled extremely quickly, much quicker than mechanical systems, the rainbow problem should no longer be observable by anyone.

Additional information on this topic can be found below as Appendix A

1c "No fixed color order, duration, or intensity" Currently, the DMD / DLP system works by having a constant know light source and modulating a mirror to adjust the intensity of each pixel. The video processor must work with a fixed color sequence, with each color having a fixed duration of type to create the image. Put directly, the system must make use of 100% Red for 2.5mS then 100% Green for 2.5mS then 100% Blue for 2.5mS.

An LED system does not contain this limit. The video processor can control the light based on the properties of the image it is attempting to display. It can control the color, the brightness, and the duration of any color the LED array can produce. Again, put directly, the processor could order up 90% Red for 1mS then 100% Blue for 2.0mS then 20% Green for 0.5mS then 50% Green AND 50% Red (a dim yellow) for 1.0mS then 100% Red and 100% Green and 100% Blue (pure white) for 1.8mS.... I hope everyone can see what I am getting at.

2. LEDs simplify cooling.
2a. "No IR / UV component of light" Current lamps produce more than just visible light, they produce infrared and ultraviolet. These must be filtered and also create a significant amount of heat which propagates through the optical system. An LED system lacks this concern and should create less cooling demand for the optics (quieter fans).

2b. "Thermal energy can be cooled directly." LEDs can have heatsinks attached to them directly to aid in the cooling of the devices without interfering with their light output. This should enable more efficient cooling (quieter fans).

3. Service life between 10,000 and 100,000 hours. With an extended service life, you would never have to replace a bulb. A MTBF (Mean time before failure) of 10,000 hours is considered the benchmark for consumer electronics; for a tv thats watching 4 hours a day, everyday for over 6 years.

4. LEDs are more robust than existing bulbs. LEDs can withstand far greater mechanical shocks than bulbs can and should mean a sturdier mobile projector.

5. Arc bulbs require a complex power control system to prevent the color of the light from changing. The power control system for LEDs is simplier.

6. Instant on LEDs do not need to warm-up and stabilize as arc-bulbs do and projectors using LEDs would turn on as fast as direct view LCDs.

Enjoy!

Appendix A: Continued 1b information
Note, the following is a fairly technical list of articles/quotes and I apologize that it is not intriniscially obvious why this proves LEDs can elliminate rainbows.

From this article (http://www.extremetech.com/article2/0,1558,1153392,00.asp), the following quote is used:
According to a talk I had with Gene O'Donnell, Director of Advanced Displays and Systems at Thomson (RCA), he said an Air Force study of DLP color breakup determined that 2500 sub-frames per second would be required in a sequential color display single-chip DLP system in order to totally avoid color breakup effects.
This equates to a subframe lasting for 400uS. Also please note that a subframe is not a complete image, but the longest time that one color is displayed before switching to a new color.

From this DLP White paper (http://www.dlp.com/dlp_technology/images/dynamic/white_papers/152_NewApps_paper_copyright.pdf)
In this phased reset mode the minimum LSB period is determined by the mirror transition and settle time (about 18us...) plus the time required to reload the mirror section with new data (about 6us).
That gives a switching window of 24uS. This is significantly faster than our mimimum subframe duration.

Although I won't site any sources (I leave it up to the critic to disprove) LEDs can switch in less than 0.1uS, but even at 10uS they still more than fast enough.

[Edit: Added 1b Info]

Wigggles, while a lot of T1-3/4 LEDs have peak forward currents much higher than their rated forward current, this isn't true of the Luxeon parts. I don't have any data sheets in front of me, but I think the 350mA parts have a peak forward current of 500mA. Besides, you don't really want to do this. One advantage of having each LED running only 1/3rd of the time is that keeps the junction temperature to a more manageable level. The problem is not creating the light, though. The problem is collecting and collimating it, and getting it through an optical system. Larger sources mean larger optics or less efficient systems. I'm not sure that this particular nut has been cracked yet.

scoby,

In the white paper that is EXACTLY how Lumileds did it. They said they pulsewidth modulated the LEDs output in a burst mode.

I wish they still had the white paper up and not just the presentation, but on a previous thread

http://www.avsforum.com/avs-vb/showthread.php?s=&threadid=249980&highlight=luxeon+LED

I did quote the whitepaper directly:

quote:
--------------------------------------------------------------------------------
It is important to note that for the DLP it is assumed that the luminous flux loss by duty cycling the LEDs is compensated for by driving the LEDs at higher current densities.
--------------------------------------------------------------------------------

They aren't specific but if you do the calculations they have to be driving the LEDs in the burst mode to get their claimed 36% efficiency for a single chip DLP.

Sustained output for an LED at 3 times its rated power (or current) is obviously going to burn it up and not produce anywhere near 3 times the rated brightness. But if you do 3 times the current in little 3ms burst every 9ms (roughly what a 6x colowheel would do), will you get the same amount of overall light that you would get from running the led at the rated current with a normal 100% duty-cycle?

I think the answer is somewhere imbetween but this IS what Lumileds is doing and I'm sure is what NEC plans to do as well.

-Mr. Wigggles

Hello all,

Just to add some support behind Wiggle's comments; most LEDs / Laster diodes are more reliable and have higher outputs when they are run in non-continuous modes. The datasheets are written to describe maximum continuous mode.

It's one of those things that if you honestly don't believe it, please go ahead and test it (it's a cheap and easy experiment). Get two LEDs, drive one at its maximum rating continuously, and drive the other at 33% PWM (use something like a 200Hz switching speed) with 3x the maximum current. Looking at the devices, they will appear to be about the same brightness. Now just wait a few minutes/hours and see if the 3x LED burns out. If it's going to happen, it shouldn't take too long.

In general, these devices "burn out" due to thermal concerns.

Hope this helps!

Andrikcos,

Thank you for the positive feedback.

With the dual light banks, I'm assuming this is part of that whole "2 pixels in 1 mirror thing," right? To be honest, I haven't yet read up on that.

If I'm not on track, then I'm sorry; I couldn't follow your idea! ;^)

Davandron: I think you are mistaken on a few things

a) I don't think it is the wheel that is the limit but the DMD chip, in theory there is nothing that stops the wheel from spinning at the speed of sound. So the rainbows and all the rest will still be there

b) I am sure one led does not produce much heat, but I don't think any one lead produces light any where near what is needed, you will probably need hundreds of LEDs to get the light needed. at 1000 lumens @33% efficiency that means the LEDs need to produce 3000 lumens from the led array

c) arc bulbs used in projectors don't have a filament

"I want my L. E. D." (think of the tune from Dire Straits "I want my MTV"):D

If only the cost and brightness can be worked out at reasonable price this could be the Holy Grail of FP! Anyone have informed knowledge on when these might be available - at least for a public demo of a prototype?

Originally posted by AnthonyP
Davandron: I think you are mistaken on a few things

a) I don't think it is the [color] wheel that is the limit ... So the rainbows and all the rest will still be there

b) I am sure one led does not produce much heat, but ... you will probably need hundreds of LEDs to get the light needed.

c) arc bulbs used in projectors don't have a filament

Thanks for the post Anthony. If I may, I'd like to respond to your thoughts

Regarding A; the thrust of the original advantage was that LEDs do not suffer from having a wheel control when a given color is displayed. Without any difficulty, an LED system could run at a 1mS color window, which would be the same as "5x" color wheel speed, and would create an image in which very few people could see a rainbow problem.

A continuation of the thought, LED based systems can dynamically change color order, duration, and intensity to best represent a picture. Put simply, they could have a "Red Yellow Green Blue Violet" color order.

Regarding B; you're correct that LEDs do create thermal energy at the junction and the array will need cooling. Fortunately, the light leaving the array contains no IR or UV. This means the rest of the optical systems does not need to be cooled, unlike current systems. And since LEDs can have a heatsink attached to them directly, without interfering with the light, they are easier to cool.

Regarding C; again you're correct, arc bulbs do not have a filament. In my rush to finish the posting I figured that would work as an analogy. My point was that bulbs will always be more fragile than LEDs, and I will update the post to reflect that.

Thanks for the input!

Originally posted by AnthonyP
Davandron: I think you are mistaken on a few things

a) I don't think it is the wheel that is the limit but the DMD chip, in theory there is nothing that stops the wheel from spinning at the speed of sound. So the rainbows and all the rest will still be there
The power/energy required to spin a wheel twice as fast is goes up by a factor of 4. This isn't easy on the motor and it makes balancing the wheel and keeping it quiet more difficult (among other things).

Now if you just put more segments on the wheel you run into the following: With a colorwheel there are "spoke times" where there is transition from one color to the next. During that time the projector can't output any light it shuts the mirrors off. The more segments, the less area that is dedicated to a color and the more area that is taken up with transitions.

None of these issues are present with LEDs.

b) I am sure one led does not produce much heat, but I don't think any one lead produces light any where near what is needed, you will probably need hundreds of LEDs to get the light needed. at 1000 lumens @33% efficiency that means the LEDs need to produce 3000 lumens from the led array
From my post yesterday:

http://www.lumileds.com/pdfs/techpa...-BA-Paolini.PDF

we have:

http://mrwigggles.250free.com/lumileds-1.jpg

and

http://mrwigggles.250free.com/lumileds-2.jpg

These manufacturers suggestions don't support your claims. (mind you that these claims are for LEDs made 1.5 years ago. Newer LEDs are even better). I think a 5 Watt red LED would actually be enough. The other colors would need to need arrays, but it wouldn't take "hundreds"

c) arc bulbs used in projectors don't have a filament
yep.

-Mr. Wigggles

Regarding A; the thrust of the original advantage was that LEDs do not suffer from having a wheel control when a given color is displayed. Without any difficulty, an LED system could run at a 1mS color window, which would be the same as "5x" color wheel speed, and would create an image in which very few people could see a rainbow problem.

A continuation of the thought, LED based systems can dynamically change color order, duration, and intensity to best represent a picture. Put simply, they could have a "Red Yellow Green Blue Violet" color order.


I don't disagree with the premises, just the hasty conclusion. I agree on the properties of the LEDs, but most of it will stay the same and if there is a difference it will be slight at best. It is not the wheel that determines the speed but how fast those mirrors can go on/off. The projector will still need to sync the position of the DLP mirrors with the LEDs and so there is a possibility for rainbows will still be there. For instance if someone builds a DLP with a DLP built for a 2x wheel, then the LED's will have to have a cycle equivalent to a 2X wheel.

Anthony,

I guess I'm not following you very well. Allow me to repeat what I believe you are saying;

The DMD's mirror slow flip speed (refresh rate) is responsible for the rainbows, because the mirrors can not change positions faster than the human eye can detect.

Is that a correct re-statement?

Davandron,

I think Anthony is saying:

You can't just throw a LED light source into an existing design and get fewer rainbows. A 5X projector is going to be a 5X projector no matter what the light source is and will have the rainbows associated with a 5X design regardless.

That I agree with. However, I think the main reason TI is at 5X right now is for the reasons I stated - there are compromises in performance associated with going any faster. I listed two compromises above but I bet there are more. Most people don't see bothersome rainbows at that speed so leave it alone.

For an LED based projector, I can't imagine TI staying at 5X when those compromises are no longer there with LED illumination. I think they would go to at least 10X.

-Mr. Wigggles

Wigggles, wow, I'm impressed by that efficiency. However, I think that is based on single parts for each color. It would be very hard to achieve that with an array. The problem is that single parts just don't have very high light output yet. Lumileds doesn't make a 5 watt red LED and doesn't have one in their future roadmap. The problem is with the AlInGaP chemistry and high current. Even if they did and they had the same efficacy as the 1 watt red parts (44 lpw), they'd only have an output of 220 lumens. Blue is around 30 lumens (6 lpw) and green is 120 lumens (24 lpw). They're nowhere near the light output needed to create a 100 lumen projector, let alone a 1000 lumen projector. The problem with running a LED at 3x power for a 1/3 duty cycle is that the junction temperature is going to be the same as if you ran it at full power (obvious, I know). What you aren't realizing is that running a Luxeon at full power significantly lowers its light output, changes its color, and severely curtails its life. Even with good cooling, you would struggle to keep temperatures under 100C, when their specs are given at a temperature of 25C. You would want to run it at it's rated power for a 1/3 duty cycle if you wanted the device to work right and last. Even then, you would need serious cooling. So 1/3 duty cycle and 36% efficiency would mean you would get about 10% of the rated power of the LEDs out the lens of the projector. You might be able to get 50 lumens from a projector using 3 5-watt parts. Pretty nifty, but not home theater. I think this will work if you get a 10x increase in light out of the LEDs, both by using higher current parts, along with increases in LED efficiency.

scoby,

At the very least don't shoot the messenger. If you think the Lumiled's claims are far reaching just say so.

Do I need to post every picture in the presentation? The presentation predicts:

http://mrwigggles.250free.com/lumileds-3.jpg

That we would have a 180 lumen design by the end of this year.

This is getting boring. I spend time gathering information that people don't read. I post ideas that people don't understand. And I get into arguments about things that nobody here is qualified to answer.

Scoby, What is the light output of a 5 watt Luxeon that is driven at 15 watts for 1/3 rd of the time? How soon will it fail? Why does it need exotic cooling when other Lumiled documents suggests otherwise?

Say what you want - I am out this thread.

-Mr. Wigggles

Wigggles, I've been impressed with your posts on a lot of topics. I'm not trying to rain on your parade. I do have some experience with these parts, though. Lumileds rates their parts at 25C, which is all but impossible to achieve in actual use without exotic cooling. Even if the 25C number were available, its still nowhere near enough light. It will be some day in the future, but not this year or next. Lumileds still hasn't hit their Q4'02 goals from their Q2'01 roadmap, so I don't put a whole lot of stock in their predictions.

Anyway, why don't you take a look at Lumileds' data sheet for the Luxeon V at http://www.lumileds.com/pdfs/protected/DS34.PDF. Of particular note should be the thermal resistance on page 3, and relative light output vs. junction temperature on page 5.

But it's even more simple than that. A discharge lamp produces about 60 lpw. LEDs average about 20 lpw. Since the LED optical system is 3 times as efficient, that means they are about on par. Same power input, same light output...so the same amount of heat to dissipate for a given brightness. However, the lamp can tolerate high temperatures while the LED cannot.

Yeah, these groups can eat up a person. But hey, its fun!

I think people are just posting their thoughts, ideas, hopes, and questions. And some others might be playing devils advocate or even critic, but those are always there as well. ;^)

Oh and for what its worth, think of posting here as contributing to a library. Many times I've searched through old threads to learn about things so that I didn't have to post up new questions. So maybe that helps, Wiggles. Many people benefit from your posting info, some just having read this thread yet ;^)

Originally posted by Andrikos
An idea just came to me and I want to pass it by the experts. Be kind if it's ultrastupid... :)

ok, we have the xHD3 chip and all its (theoretical) advantages over 720p by essentially using the same chip (almost).
consider this:
6 LEDs (2 of each RGB color).
One RGB assembly is stationary and illuminates the left half (for example) of the "screen" for the first 1/120s and the other RGB LED assembly can "swivel" in the X-axis so it can illuminate the right half of the screen for the next 1/120th of a second.
The swivel would be necessary for a non-fixed throw projector.
For the case of RPTV, both RGB LED assemblies would be fixed with no moving parts whatsoever which makes it ultra-reliable.

I hope I'm "explaining" this semi-competently. :)
Is this doable?

OK, i read up on the HD3 DMD Interlacing (http://www.avsforum.com/avs-vb/showthread.php?postid=3745512#post3745512)... and I don't think moving the light source would produce the desired result since the thing you are illuminating (the DMD) doesn't appear to move.

The HD3 design tricks the optical assembly into thinking the entire mirror array actually moved.

But for what its worth I really don't like the whole interlaced DMD design...

You can't just throw a LED light source into an existing design and get fewer rainbows. A 5X projector is going to be a 5X projector no matter what the light source is and will have the rainbows associated with a 5X design regardless.

that is what I meant

I listed two compromises above but I bet there are more. Most people don't see bothersome rainbows at that speed so leave it alone.


but you are assuming that all the compromises are wheel related. That is where we disagree, I think most of them are DLP based. If it was only wheel based, then why do we still have 2x machines? I am sure from a manufacturing point of view it would be easier to just buy 5x motors and put them in all projectors once they found a way to stabilize the wheel at that speed. I can concede that it might be easier to make a faster LED then colour wheel, but I am no where near convinced that the only thing stopping a 10x projector was the wheel it self.

At the very least don't shoot the messenger.

I know this was aimed at scoby, but if you felt that way with me I apologise. You are one of the people on this site that I consider extremely knowledgeable and enjoy our discussions.

I spend time gathering information that people don't read.

tried your link, but it does not work. Can't blame me or others for that. If you will e-mail me the article (assuming you have it on your Hard drive, I will definitely read it.

I post ideas that people don't understand.

I think we do understand them, it is just that we see them from a different point. I agree that if it goes up to 180 by the end of the year that it will be good, but who wants 180, that is not enough. OK, 100 might have been over stating stuff, but also that graph does not say much (without the accompanying text). For instance is that output from a make shift projector? is that using 1 white LED and colour wheel? 3 LEDs RGB or more then three LED's or is that one white LED bouncing giving a black and white image without the colour wheel?

And I get into arguments about things that nobody here is qualified to answer

that I agree, I am the first to agree that I don't know much about LEDs or Projectors. But that does not mean that the discussion here is useless. I am just trying to give a more realistic view. It is easy to say that there will be a 3 LED projector and rainbows will go away because the LED can go on and off extremely fast. And in the future it might be true. But even with the graphs you showed assuming best case scenario will not end up with such a projector before a long time. Both because LED's are not there and because DMDs are not there.

I think people are just posting their thoughts, ideas, hopes, and questions. And some others might be playing devils advocate or even critic, but those are always there as well. ;^)

I agree, and I guess Devils advocate is my part in this thread. but I am posting why I don't think it is as easy as some people think

Originally posted by AnthonyP

tried your link, but it does not work. Can't blame me or others for that. If you will e-mail me the article (assuming you have it on your Hard drive, I will definitely read it.

Sorry, I have to answer this.

The one on page 3 does work. The one that wasn't read.

-Mr. Wigggles

Wigggles, I read the paper on page 3. It does actually mention why arrays won't work, and why they are talking about 30" and 40" RPTVs that will be available in "a couple of years." It's the entendue problem, which has been mentioned here before. I've heard of possible solutions, but never seen any discussion about how they might work.

The problem is light output and heat. I think I've figured out where your confusion might lie. A 5W LED does not mean 5W of radiometric flux. It means 5W of input power (1.4A, 3.5V). Actual emitted flux is 500mW or less. All of the other energy is dissipated as heat (4.5W). LEDs are really efficient converters of electricity to light (nearly 99% quantum efficiency!), but most of the light is lost to total internal reflection and becomes heat. If you could get a higher percentage of the light out of the die, you'd both improve efficiency and reduce heat. A five-fold increase in flux from the same input power would also halve heat output.

I'm not saying that LEDs won't work as light sources, or that I don't think they are really cool. I'm just saying they won't work now for FPTV, and there needs to be about a 10-fold improvement before they could.

The one on page 3 does work. The one that wasn't read.


dwnlded it and will read it, thanks

OK, I looked at it. so the graph must be talking about a 3 LED DLP reaching 180 (i.e. there is only 3LED architectures discussed). also not certain if it is a full projector or comming out after the chip. Even if they make it 200, they would need to use 15 LEDs+ to get 1000 lumens

Anthony, yeah, but it is a 2001 projection based on a roadmap that hasn't been met (not even close!). The brightest red part is still only 44 lumens. That pretty much limits a 36% efficient RGB DLP to about 50 lumens. LEDs have a huge amount of potential as projection sources, though. Increasing the RGB refresh rate would make rainbows disappear and the elimination of spoke time would reduce dithering a bit. LED rise and fall times are ultra fast, so syncing the mirrors to the source would be simple. What we need to see is a big increase in efficacy. The heat problem actually goes down as efficacy increases, but it would still take active cooling (thermoelectrics perhaps) to keep everything under control. If, somehow, the entendue problem could be solved, then an array of LEDs could be used to get output similar to a bulb projector. The projector would still have just as much heat to dissipate (about 150W), but it would be easier as it would be spread out.

Anthony, yeah, but it is a 2001 projection based on a roadmap that hasn't been met (not even close!). The brightest red part is still only 44 lumens. That pretty much limits a 36% efficient RGB DLP to about 50 lumens.

true, but how do we know where they (or any other) has reached at this point? there is a difference between product and lab, all I wanted to show was that discussing g a LED source might be fun, but people should not get their hopes up that next year there will be a 10x DLP that uses 3 (or 6)LEDs. What I wanted to show was that yes 100 might have been a bit of a hyperboly, but no one (not even this document) is talking about a single or 3 LED projector that will be used for big screen in the near future. And if we assume that they have not or cannot do better then the 50 lumens discussed in this thread then 100 LEDs is not that far from the truth.


LEDs have a huge amount of potential as projection sources, though.

I don't disagree. The real questions are can we make LEDs that is powerful enough and when? If this pocket projector will be available 20 years from now it might be too late because someone else came out with something better

Increasing the RGB refresh rate would make rainbows disappear and the elimination of spoke time would reduce dithering a bit.

I agree with that, but I think it will mean that it will need more then just a faster light colour change. It will mean different drivers and needing different faster DLP chips and making a DLP chip faster will add it's own constraints. Also if we agree with Mr.Wigggles that the wheel is what is limiting the speed now, then why would TI work on a chip that cannot be marketed until the source changes (i.e. get something that is faster) TI will only start working on it once the LED projector is out.

LED rise and fall times are ultra fast, so synching the mirrors to the source would be simple.

I understand that they are fast. But let's take the Archimedes wheel (this was a wheel that does not have sections (RGB or RGBRGB) but regions (so part of the chip will show red image an other section the blue part....) as a comparison. I know this wheel would be more complicated to sync because the processing is suppose to divide the image into it's parts. But I would guess the reason it is not showing up is also because it is at the limit of the DLPs capacity. Don't forget that the faster the chips are changing the more the chances something will go wrong

What we need to see is a big increase in efficacy. The heat problem actually goes down as efficacy increases, but it would still take active cooling (thermoelectrics perhaps) to keep everything under control.

I agree, never argued that point. All I meant is that those LEDs need to get A LOT more powerful before a three LED machine is built (at least one where the image can be measured in feet)


If, somehow, the entendue problem could be solved, then an array of LEDs could be used to get output similar to a bulb projector. The projector would still have just as much heat to dissipate (about 150W), but it would be easier as it would be spread out.

I don't have a problem with that, but you will still need the fans and the same cooling. I jumped in when Davandron said that LED's mean that there will be no more rainbows and no more need for cooling. All I said is that you will need a lot of LED's to be able to get a LED projector (with today's technology) so cooling will still be an issue. And that a LED projector will not be able to take advantage of the change speed of LEDs until there is a DMD that can do that speed.

Isn't the entendue problem an increcibly hard one in general? I mean, there are probably "solutions" but the cost is so astronomical as to make them useless right now.

I'd bet more on higher output over time to at least limit the array size needed...

Does anyone know the lower limit to size of an LED? Why couldn't 3 16-9 arrays of hexagonal shaped leds be made into a solid state 3gun projector. With 1080 rows of LED's it would make them approximately .004 per LED at a panel size appx 4x7 for 16-9 resolution. Seems like it would give all the advantages of CRt with much less bulk. With so many LED's, LM should not be an issue, and probably wouldnt even need exotic LED technology. Optics would be an issue, but one already solved with CRt projectors. For direct view, the LED's could be siamesed into one device with RGB sections distributed like pie slices with similar advantages. I guess the main problem would be whether performance can be maintained as the size drops.

JPP

If I'm understanding correctly, then cost would be a problem.... at only NTSC (720x480), thats 1,036,800 individual LEDs.

Unfortunately, they would have to cost 0.1 cents each for a total materials cost of only ~$1100. And that screen would probably cost a lot more retail.

This is true, but the same could be said for each individual transistor in a DMD device.

All,

Just stumbled onto this:

"Experts Highlight Projection Summit at InfoComm 04
The detailed agenda for the Projection Summit is now available for review online, and it features a broad range of industry leaders and experts. The conference program has both a market and technology track, each with six sessions, as well as keynote speakers and an analyst forecast debate...

[Topics Include:]

New technologies: A range of leading-edge technologies will be presented and reviewed. Topics include multiprimary color systems, LED illumination and more....

Projection Summit 2004 will be held at the Georgia World Congress Center, Atlanta during InfoComm Week, which begins Saturday June 5 and runs through Friday June 11"

From AVVideo.com (http://www.avvideo.com/articles/viewarticle.jsp?id=25394)

JPP,

Unfortunately because of the way the devices are manufactured it is not comparible. If LEDs were manufactured as a large sheet of individual devices then they could become affordable displays, and thats the concept behind OLED displays. But that technology is only at the 2.3" consumer display size point (http://www.kodak.com/US/en/corp/display/index.jhtml)

Those 2.3" displays, though, have no screendoor effect.... :)

Rogo, you have to be at less then 1 screen width away :)

you can also put 1000 of those screens together to get a big screen :)

That would be a serious, serious pixel count... For all those looking for 4K x 2K, it'd offer that in spades. Of course, the "inter-screen screendoor" (i.e. the gap between those 2.3" panels) would be brutal. :D

:), I know we are talking more like 50-100 screens wide, and not a 4x4 or something like that Plasma wall. But how much border must be there (i.e. cannot get rid of it) right now it would be around 1" (half an inch per side)

Active Area (HxV) ------------------- 43.806 x 32.92 mm
External Dimensions (HxVxD) ---- 52.0 x 45.4x 1.72 mm

but I am sure with time that the border could be decreased a bit, especially if built to be "puzzle" pieces

on the other hand
http://www.kodak.com/US/en/corp/display/sanyoFlat.jhtml using 15" panels
if they have the same border limits, 100 of these panels in a 10X10 screen might not be bad :)

we can always call it the pane glass window effect :)

On a semi-serious note, I do believe a tiled OLED array with zero borders will evventually be possible and that it is truly the path to mega displays with potentially giga-pixel resolution (certainly dozens of megapixels).

If you build it with joining connectors on the back of the substrate and can seal the OLED array with a <1 pixel seal (OLEDs need to block out air very carefully), it could be done because there doesn't need to be an inter-pixel grid that is fed from the display edge... The inherent panel is so thin, you can locate everything behind it.

Originally posted by rogo
On a semi-serious note, I do believe a tiled OLED array with zero borders will evventually be possible and that it is truly the path to mega displays with potentially giga-pixel resolution (certainly dozens of megapixels).

If you build it with joining connectors on the back of the substrate and can seal the OLED array with a <1 pixel seal (OLEDs need to block out air very carefully), it could be done because there doesn't need to be an inter-pixel grid that is fed from the display edge... The inherent panel is so thin, you can locate everything behind it.

Many are claiming that OLED will be the way of the future, the main issue is the size of the panel that can be realized cost effectively in the short term.

I don't know if zero border would be possible, but I think if they bring it down to 1/8 of an inch (so that it is 1/4 of an inch in total it would not be too bad. An other idea (don't know if it would be possible) is to make the borders so that they overlap.

red=OLED
yellow= border of OLED#1,
blue= border of OLED#2

also since it is a light producer, there might be leakage at the borders so actual size might not be the same as perceived size (not sure of this)

I think a zero border is possible. And without it, I don't believe the "tiled idea" has a chance of working.

The problem with LCD is that the panel needs to be sealed across a relatively thick area and also there is a need for there to be wiring along the edge of the display.

OLED displays are much, much thinner so the big seal isn't required. And OLEDs are emissive, not tranmissive (like TFT LCDs). So there is no reason the "edge pixel" needs any electronics beside it. It can be driven from the back solely. And the overall panel thinness allows for a "wiring layer" to sit behind the array of emitters without making the panel too thick overall.

Finally, with "printable OLEDs" being the grail that everyone in the industry is seeking to move toward, you are looking at an array on a flexible substrate that is theoretical printed like an ink-jet would make a photo. Unless there is something inherent I'm missing there, I don't see why you would need anything outside the "edge pixel".

Mark

One issue with large OLED arrays may be refresh rate due to charging time. A large panel might have a considerable RC delay from wiring capacitance.

Mark, I agree with the holy grail. But there are many plasma walls today and those end up having much more then an inch in between them. I am also looking at it in shorter term. Obviously if you could print OLEDs on roll up screen then that is a totally different subject.

I think phase1 would be the equivalent of a plasma wall. You would buy 100 screens ( with each screen being a display in it's own rite) that will be in a box (not exposed circuitry) and then you bring them home place the cables on the wall to form a grid, then you install screen #1,1 and plug the cable in the back, put the second screen and attach #2,1 then you bring all those cables and attach them to a driver/scalar device. Obviously the one I described is the easiest to manufacture, but in theory the installer might not even need to use cables because it could be part of the screens casing (i.e. the two screens overlap where the connection happens (kind of click and connect) then electronics take care of the rest. If they are enclosed to begin with then the plastic must have some thickness and that will be shown in the display


Now when you get an OLED screen that can be rolled up, then yes, all the rest is moot, but until then I think I could be happy with an OLED screen that has a 1/4 or 1/8 of an inch line every couple of feet because moving an 8', for an example, screen that is rigid would be a pain.

Right, now we are on a very similar page. Let's start building it ASAP. :)

A beautiful tiled OLED display was shown in May of last year by Sony at the Society for Information Display (SID) Conference. Here is the link to pictures of many of the OLEDs on display. The 20"D Sony was made of four smaller displays with a nearly invisible seam. It looked great.

However, the best OLED that I have seen is from Samsung SDI. The picture is #5 on the same page. 15.5" diagonal WXGA. Fantastic.

I will be at this years conference in Seattle at the end of the month and expect to see a lot more OLEDs on display.

Sorry. Here is the link.

(ckido8.yz.yamagata-u.ac.jp/pc/OLEDnews/OLEDnews052803_1.htm)

What's "aperture ratio" ?

Aperture ratio = fill factor = the percent of each pixel that is active / illuminated vs. the percentage that is inter-pixel "stuff". 33% is bad. But on emmissive displays, it might be tolerable, at least initally.

Mark

I guess this is the Sony that you are talking about

http://ckido8.yz.yamagata-u.ac.jp/ELpics/sony1.JPG

we are actually talking displays that can be hooked together, and not OLED panels that are hooked together in one device (i.e. if that screen was 6'-10' wide it would be impossible to move)

does anyone know what this is all about?

http://ckido8.yz.yamagata-u.ac.jp/ELpics/samusung41.JPG

this is cool
http://ckido8.yz.yamagata-u.ac.jp/ELpics/pioneer2.JPG

AnthonyP

The Japanese term in the middle picture (kagami) means mirror.

Does that explain it better?

Dave

Anthnony & Dcottle

They are showing a display which emmits on BOTH sides. This has to do with cell phones, where they are working towards double sided displays to reduce costs.

The inherent OLED panels are a fraction the thickness of LCD. In fact, some of the prototype monitors have been thinner than the top of a laptop lid, even at 15" or so.

Found a GREAT application note on pulsed operation vs continuous operation of LEDs

http://www.stockeryale.com/i/leds/lit/app001.htm

Also I've been continuing to update the Advantages post, those interested might want to check it out. I've got a quick link in my signature.

dcottle- Davandron thanks, that did help, I did not realize the smaller picture was the reflection (almost looked like the smaller pic was producing the larger one.

Davandron: cannot see how that would work (except for icons or if the screen gets flipped L/R when open ) if there is writing that is readable from the front it will be written the wrong way on the back.

The screen gets flipped when it's opened. It's not perfect, of course, but given the way cell phones are used, it's kind of brilliant. Not only will it save several dollars per phone, it will save several millimeters in thickness and also several milliamp hours in battery use.

Anthnony,

Trust me on it, what they are planning works. ;^)

It's for the flip phones that currently have two displays. When its closed you see the outside display, when open the inside display. They want to make it one display that you can see from both sides and then they will mirror and flip the text/images based on whether its open or closed.

Guess its easier to understand if you can hold one...

More than one way to skin a cat

There is something I've been trying to figure out how to add to the Advantages post, that could be understood by most people why LEDs are an advantage. I'm going to try it here and hopefully work it out before it goes into the other post. If you all understand it then maybe you can help me rephrase it appropriately.

In all systems, the goal is to control the energy reaching the screen at one point relative to another point on the screen. But the energy levels must be more varied than simply full on vs full off. This could be called an analog function; a system that contains significantly more than two states.

But a digital system only knows two states, so for a digital system to produce an analog output it takes advantage of averaging over time and is called Pulse Width Modulation.

So a Full On for 1/9th of the time, then Full Off for the remaining 8/9ths of the time would average out to 11% of Full On (a mostly Off system).

A system like I just described could have 10 analog states (0%, 11%, 22%,... up to 100%) and makes use of a single variable.

LED projectors would have TWO variables to control the amount of energy reaching the screen; they can modulate the mirror and they can modulate the LIGHT iteself!

Why is this a big deal? Well, when combined it allows for some strange timing conbinations.

Lets go back to our 1/9th example and add something else; lets say that during the 1/9th we have the light at 50% intensity and then during the other 8/9ths we have it at Full Off (0% intensity). Our average is 5.5%, not 11%

So if we wanted 11%, how would we do that? There are now two methods:
1.) 1/9th Full On, 8/9ths Full Off
2.) 2/9ths 50% On, 7/9ths Full Off

Lets apply this concept to the 8-bit red channel of a projector. Normally, to display the very dim color of 1/255 red, we would need to flip the mirror on for (1/30 of a second) x (1/3 of that time for red) x (1/255) = ~43.6 microseconds (or uS) of 100% light.

This means that our system has be be able to flip the mirror on and then off again in 44uS to display that 1/255 shade of red (the 1/255 is also called the Least Significant Bit, or LSB, time)

But with the LED, we can use approach number two from above! We know that by halving the Light during the LSB, we are able to double its duration and still get the same amount of energy... with one small kink; since we don't gain any time, we have to make up for that doubled LSB by increasing the length of the system:

(50% light) x (1/30) x (1/3) x (2/256) = 86.8 uS of 50% light (equal to 43.4 uS of 100% light)

Ah-ha! will yell the critics, you've got less energy and now your system isn't accurate! Well, not entirely...

To increase the duration of the LSB I redivided the rest of the time, and this creates a shift. The next bit would be 2/256 at 100% instead of 2/255, then 4/256 at 100% instead of 4/255, and so on until you got to the MSB of 128/256 instead of 128/255

What this means is that Full On (255/255) becomes 255/256 of the maximum energy possible in 256 of 256 periods... but the light is never off in all of that time... we lose 1/256th of the maximum energy possible in that doubled-LSB, because theoretically we could have had 100% instead 50%. But the system runs at our 100% light level definition.

The linearity problem's root is that we were at first saying 1/255th of the energy but then applied that to a 1/256th system (the LSB+1 was 2/256)
To solve the linearity problem on the LSB, the light source is run at 50.195% or (1/255) / (2/256)

......

OK so I'm trying to point out that there are now two variables and that allows for either relaxed timing or enhancing grayscaling... should I just talk about dynamic range instead? Its difficult for me to teach because the concept is so new to me....

I understand, all I said is that it would need to flip the info depending on if the phone is closed or open assuming that when it is closed you are reading the outside and when open the inside.

To answer Andrikos, OLEDs can be very thin. The organic layers are on the order of 100nm. What accounts for the bulk of the thickness is the glass (or plastic) substrate and the glass or metal encapsulant. OLEDs must be hermetically sealed, so they are typically fit with a metal or glass cap.

As far as the mechanical durability of the OLED, it is entirely dependent upon the substrate and the encapulating layer. The OLED layers are extremely delicate.

Contrast ratios are very good, >1000:1. Peak brightness can be exceptionally high, but running an OLED at high brightness is currently an issue across the industry. For this and other reason,s I don't imagine OLEDs will be appearing in RP or FP applications anytime soon (unfortunate for readers of this forum). They are really ideal for high definition video because of the very short response time (unlike LCDs), their excellent color gamut, and their wide viewing angle.

Aperture ratio isn't as big deal in emissive displays as it is for transmissive displays. For OLEDs, it determines how hard a pixel has to be driven to achieve an overall display brightness. Today's OLEDs have limited aperture ratios because the emission occurs through the transistor layers on the substrate. The pixel circuitry takes up a portion of the display real estate. This does not scale with display size, so it could be a problem for small, high resolution devices.

Tomorrow's OLEDs are more like LCOS chips. They emit upward, away from the substrate, so apertures can approach 100%.

Can you poke the screen with your finger or a pen?

yes, have you seen the Chameleon remote?

Contrast ratios are very good, >1000:1.
Is this on/off or ANSI? If ANSI, this is breakthrough. If on/off, this is troubling.

This technology emits light, right? It should have an extremely high on/off CR (like CRTs) since it shouldn't emit anything when showing black.

First in the world, Upstream Engineering introduces a revolutionary optical technology that will enable video projection from matchbox-sized device running on batteries. (http://www.upstream.fi/)

I am on the road right now and I have to say, I'm ready for a tiny projector you could shine on a wall to give you a big screen that's portable.

Mark

Mark,

Unfortunately, that company is only claiming to projector a "travel-TV sized color projection."

yup, a far cry from somethuing we (i.e Digital Hi-End Projectors ) can use. On the other hand imagine it built into your keyboard, that would make a nice flat screen :)

They did specifically mention entendue; hopefully they weren't just name-dropping. Perhaps it will be useful in getting arrays of LED's to work for pj's.

Davandron, this list seemed to suggest what I want might be real...

he following is a list of applications where a tiny projector might do a change for good. The list is not complete, rather it should be taken as an initiative for wild imagination...

"- pocket travel television - pocket media player - external display for laptops - external display for mobile phones - personal video projector at airplane seat - secondary television displays for home - display for handheld gaming device - display for mobile video conferencing - windscreen display for cars - etc..."

I could imagine a radically different laptop if such a thing were possible.

Radically different.

Mark

yep, make it a touch tracking projection and put it in a matchbox with that laser projected keyboard on the opposite side. Add it to the guts of an OQO mini PC and you've got a full size functional PC smaller than a PDA. Add a phone and Wifi. Now we're close to the baton PC that Apple conceptualized 15 years ago.

You are getting near what I'm seeing. It could be a fabulous product.

I agree with Barking Art, I thing this could be cool with a wireless PDA (i.e. like a blackberry)

the next big japanese school girl toy will be the cell phone/camera/HDTV projector.
:)
frank

from SID2004

RGB LED Illuminator for Pocket-Sized Projectors

M. H. Keuper, G. Harbers, and S. Paolini
Lumileds Lighting, San Jose, CA, U.S.A.

A compact 60-lm RGB LED illuminator for color-sequential pocket-sized projectors has been demonstrated. The volume of the light engine, including optics, heat sinks, and electronics, was less than 100 cc. LED illuminator systems produce vivid colors even at peak brightness levels, unlike traditional color-sequential systems with a color wheel.

Holograms enable pocket projectors (http://www.trnmag.com/Stories/2004/063004/Holograms_enable_pocket_projectors_063004.html)

vsv
How many lumen would it be with a three chip design, 100 lumen?

Andrikos
I agree with most of what you say but not about brightness.
Project 100 percent white field
3-chip
r+g+b=white
single chip
first r then g then b=white

I assume that single chip led dlp is color sequential

"Why bother with 3-chip Matthias?
LEDs are PERFECT for one chip design.
You'll get 99% of the preformance, better contrast and probably better brightness by using single DMD"

Also, it seems that you have the same dithering problem by having divide any given segment of time into three (RBE could be made to go away by multiple subdividion, but not dithering).

Dream come true?

"Compact LED high-power light source - A new order of magnitude

With OSTAR, a new generation of RGB high-power light sources, OSRAM Opto Semiconductors is opening up previously untapped applications for LEDs in projection and general lighting. At more than 120 lm, this new star in the LED firmament is setting records for brightness levels. With a brightness value of this magnitude, this high-power LED out-performs existing LED RGB light sources many times over. This is made possible by advances in thin-film technology, in which OSRAM Opto Semiconductors is taking a pioneering role. OSTAR is equipped with coloured thin-film chips which enable almost all the light generated internally to be presented at the surface. Precise positioning of the chips ensures that light is distributed evenly. With its exemplary Lambertian emission characteristic, the LED provides uniform light, irrespective of the angle, in the smallest of spaces. The white point - the point within the colour triangle that defines the colour white with a particular colour temperature - can be set to different values, which means the light colour can be adjusted to suit regional preferences.

The module is ready to install, measures 3 x 1 cm and consists of the high-power chips themselves, a ceramic carrier for connecting to the heat sink and an ESD (electrostatic discharge) diode that protects against overvoltage.

OSTAR can replace conventional light sources in projection applications. Benefits include small mounting dept, high colour saturation and instant light as soon as the module is powered. The new high-power LEDs will even tolerate frequent on/off switching without suffering any damage. Medical applications are also possible. The LEDs could be used as a light source in microscopes or to illuminate operation sites in different colours with no IR component. Their special beam characteristics make the LEDs ideal for head-up displays in flagship cars. There is every expectation that further applications will be added.

To give people an idea of what these LEDs can do, a number of potential applications will be demonstrated at Electronica, Hall A4, Stand 414."

http://www.osram-os.com/news/pics/ostar_gross.jpg

Another parts:
PORTABLE FRAME

The PF-640 and PF-1280 portable frames read images from memory cards and display them on the microdisplay. USB interface is built in for download or upload of images from a PC. User can select, scroll and zoom in or out the images through user interface. The PF-640 can provide 24-bit color and the PF-1280 can provide up to 30-bit color.

http://www.hkimd.com/shared/image017.jpg

PROJECTOR KIT

The PRO-800 mini-projector kit and PRO-1280 HDTV-projector kit employ iMD's patented single-panel projector architecture, which greatly simplifies the projector optics. The kit accepts both VGA and S-video signals, and projects images on the microdisplay through a matching projection lens with 120Hz frame rate. IMD's proprietary color management optics and electronics are employed for excellent color.

http://www.hkimd.com/shared/image007.jpg

and more information (http://www.hkimd.com/)

So how bright would a Panasonic or Sony LCD projector be using this new technology? What is the lifespan?

IB

Good find.

Is it just me, or does it kinda sound like a "white-only" LED using phosphers? I mention it because the projector we've all been talking about would work best with three descreet diodes.

There's another thread on this

http://www.avsforum.com/avs-vb/showthread.php?s=&threadid=463338

just two pics
http://www.sketchup.com/forum/download.php/3,5568/rw4g.jpg

http://www.weblogsinc.com/common/images/2363715483647915.jpg

Wow...

10 years from now LED projection in high-end videophile applications will be the norm...unless of course something like flexible roll-up direct-emiting LED screens takes over first... :D

nice pics, but nothing new, the problem is that tit is a far cry from a screen that size to one that is HT size

Originally posted by Davandron
Good find.

Is it just me, or does it kinda sound like a "white-only" LED using phosphers? I mention it because the projector we've all been talking about would work best with three descreet diodes.

"This RGB light source is ready to install and consists of one red, one blue and two green thin-film chips, a ceramic carrier for connecting to the heat sink and ESD (electrostatic discharge) elements that provide reliable protection against overvoltage. At 120 lm, it is about four times as bright as the Golden Dragon and an impressive 50 times as bright as the Power TopLED."

A tiny video projector, the size of cigarette packet, will create the opportunity to do for movies what the iPod has done for music.

The unique ‘holographic video projector’, has been developed by Light Blue Optics, a company grown from the Department of engineering at the University of Cambridge. It uses lasers and holograms to create a sharp image without the need for expensive light bulbs or bulky projection lenses.

The traditional digital projector uses a white light bulb, a colour wheel of filters, and a lens to magnify the image for projection. The problem is that these bulbs are expensive at up to £400 a time, are fragile and have a short life. The increasing use of projection in many different applications has created a demand for a more robust and cost–effective projector.

The Light Blue Optics video projector works by creating a 2Dimensional holographic image of the picture in real time. The holographic pattern, which appears to the eye as a random pattern of dots, is displayed using a small liquid-crystal-on-silicon (LCOS) microdisplay and illuminated using a laser. The light is diffracted to produce a sharp, high quality image, which can be projected on to a screen or wall without the need for a bulky projection lens.

The exciting feature of this projector is that it successfully overcomes a number of technical issues:-
· Holograms are extremely complex mathematically and previously have been very slow to calculate – but the Light Blue Optics’ proprietary ‘hologram chip’ can generate 200 frames a second (video films are 50 frames a second)
· Conventional holographic images tend to be speckled – the ‘holographic video projector’ produces sharp images with virtually no speckle.
· Digital video projectors are comparatively bulky – this projector could soon be integrated into a laptop, PDA or even a mobile phone!

Products using this technology should also be cost-effective as lasers are steadily coming down in price. Red lasers are already down below £10, and can offer a 5 times improvement in life-time over a bulb.

Nic Lawrence, Managing Director of Light Blue Optics comments that the technology has many applications in consumer, aviation and industrial environments. “The possibility of showing a movie using this projector with a PDA is becoming a reality. In addition, it has serious industrial applications; a major aircraft developer is investigating the use of our technology for improving the ‘head-up’ display in the aircraft cockpit”.

http://www.lightblueoptics.com/

White LED is 7,500 Kelvin. Which is darn close.

News From CES 2005 - Palm-sized DLP Video Projectors Attract Attention
Robert Silva

In what may turn out to be a very interesting new consumer electronics product category,
both the Texas Instruments and InFocus booths at CES displayed working prototypes
of small palm-sized DLP video projectors.
The projectors shown were powered by a TI DLP chip with an LED light
source instead of a high wattage lamp, to reduce heat generation and power consumption.
Although not as bright as their larger cousins, both units on display were capable of
projecting a solid 27-inch image in a darkened room setting. Although specifications
are still being finalized,the Mitsubishi and InFocus branded projectors are expected
to hit store shelves by the end of 2005, with an expected price of about $600.
It remains to be seen how the market will respond, but it is expected that these
new mini projectors will have both business and entertainment applications.
The photos below show both projectors.


Mitsubishi LED projector

http://hometheater.about.com/library/graphics/mitsudlpmini.JPG

http://common.ziffdavisinternet.com/util_get_image/8/0,1311,sz=1&i=88158,00.jpg

Infocus LED projector

http://hometheater.about.com/library/graphics/infocusdlpmini.JPG

http://www.pcworld.com/news/graphics/119119-0046.jpg

I believe that it was stated elsewhere that the Mitsubishi and Infocus projectors have a resolution of 800x600.

If an LED projector of this resolution is estimated to cost $600, what would a 720p LED projector of the same brightness cost?

As a technophile, I love these tiny machines.
But, is there a (big enough) market for them? Even for half the price (and half the size) I don't see how they could compete against more traditional pjs like those below 1kg pjs that Plus-Vision makes since years.

Good question car_rod.

Even for $600, I can't see buying a projector with an 800x600 resolution.

But, if the resolution was high enough, and the price not too high, I think it would be attractive to a lot of people.

TI DMD 800x600+LumiLeds... this innovation may be good for ces2003,
but not for ces2005. Today, there is a good components for compact LED based projector:

1.Digital D-ILA device designed by JVC and Aurora Systems Inc.
0.70 in. Device diagonal
Digital (PWM) Driving method
12 micron Pixel Pitch
16:9 Aspect ratio
93 % Fill factor
5000:1 Contrast (device only)
1280 x 720 Number of Pixels
2. OSTAR LED from OSRAM
3. Wavien Dual Paraboloid System

...and high gain screen at least 40"

Originally posted by DaViD Boulet
One other positive about not needing a "mechanical" color-wheel.

With instant on/off LED light sources and single-chip DMDs, one could instantly change "refresh" rate. This means that the DMD could sync to 50Hz, 60Hz, 24Hz, 72Hz, whatever and instantly switch duty cycles without any video glitch or frame-rate conversion. You could play back a montage of film/video sequences with no visible scan-rate conversion artifacting.

*finally* would could get some movie playback from DLP without that darned 3-2 judder that no manufacturer has properly addressed.

intresting, this would mean GREAT news for 3D, just imagine being able to get 120 hz refresh rate, that would mean stereo would get 60 FPS to each eye. pretty neat stuff.

3D is kinda underused, but soon this might change.. James Cameron's new Film will be for digital projectors only, and 3d only.

BenQ and Samsung display LED-based pocket projectors at CeBIT

Vincent Mao, Hannover; Carrie Yu, DigiTimes.com [Monday 14 March 2005]

Both BenQ and Samsung Electronics are highlighting new LED-based pocket projectors at CeBIT 2005 (March 10-16 in Hannover, Germany) using technology from Texas Instruments (TI), according to the companies.

Both models are significantly slimmer than projectors currently available on the market, as they use high-brightness RGB LEDs and do not need to include devices such as color wheel modules and high-voltage transformers, the companies said. The projector BenQ is showing at CeBIT is palm-sized.

BenQ said its LED-based pocket projector is aimed at the high-end market, but the product schedule and price have not yet been decided, the company added.

Samsung’s LED-based pocket projector is dubbed the “Pocket Image Series.” Using TI’s 0.55-inch DMD chip, the projector supports an 800x600 resolution, a 30-lumen brightness and a 500:1 contrast ratio. The model weighs only 500g, can be used for two hours without recharging and is initially priced at around 600 euros (US$807), the company said.

A report last July stated that both BenQ and Coretronic will likely introduce 50-lumen LED-based pocket projectors in 2005, according to sources at the two companies.

http://www.digitimes.com/displays/a20050314A6036.html

http://www.digitimes.com/NewsShow/20050314A6036_files/image001.gif

http://www.digitimes.com/NewsShow/20050314A6036_files/image002.gif

"BenQ and Coretronic will likely introduce 50-lumen LED-based pocket projectors in 2005, according to sources at the two companies."
---------------------------
If they can just increase brightness by a factor of 20 they will have a nice front projector. For small RPTVs they are closer to have something useful.

IB

Head with a diameter of 1.25 mm radiates a 50 lm beam

http://techon.nikkeibp.co.jp/english/NEWS_EN/20050415/103802/20050414_nichia_whiteLD.jpg

Nichia Develops 10,000,000 cd/m2 White Light Source Using Semiconductor Laser

Nichia Corp. has developed a white light source with a luminance of near 10,000,000 cd/m2, using GaN semiconductor laser diodes. This luminance is almost equivalent to that of high-end halogen lamp products and conventional HID (high intensity discharge) lamps, and a digit higher than that of a white light-emitting diode (LED). A white light beam of 50 lm can be acquired from a round head of only 1.25 mm in diameter. The company will start sample shipments in the second half of 2005 as a replacement for halogen lamps and HID lamps.

The light source generates white light by combining light emitted from either a blue semiconductor laser diode using GaN materials or a blue violet semiconductor laser diode, and fluorescent materials that change the light wavelengths. The product consists of a light source unit containing a semiconductor laser diode, and an optical fiber whose end is coated with fluorescent materials. An optical lens directs lights emitted from the semiconductor laser diode into the end of the optical fiber, which then discharges white light from the other fluorescent materials coated end. Manufacturers can position the optical fiber's light emitting head away from the light source by winding the optical fiber, which, given its mechanical flexibility, could be up to a few meters long. The company explained that the light emitting head needs little cooling, because the light source, which generates heat during operation, can be located at a distance away from the head.

Satoshi Ookubo, Nikkei Electronics

vsv,

Wow! Thanks for that.

I wonder what's at the other end of the red/black twisted pair, how big it is, and how much power it consumes to get those 50 L.

It can't be too much power -- are those 28 or 32 ga. wires feeding it?

"Nichia Develops 10,000,000 cd/m2 White Light Source Using Semiconductor Laser"
---------------------------------------------------------------------------------------

Wow! I suppose you could use 3 of them for a 3 chip LCD projector.
I do not know the meaning of the numbers. What do you think they would mean in terms of potential projector output? If you used 3 of them in a Sanyo PLV-80, which is supposed to have 3000 lumens, what would the light output be? Could you match the old Sanyo lamp with these units?

Finally, after years of little progress I see light at the end of the tunnel. That light may be a gorilla holding a diode laser.

http://techon.nikkeibp.co.jp/english/NEWS_EN/20050415/103802/?ST=english

IB

Knowing very little (okay, nothing) about how lighting is done now, couldn't something like this basically revolutionize how FPTV and RPTV is done? Can you add more than one without screwing up how even the lighting is?

-RandomDave

I forgot to ask, what would be the life expectancy of a semiconductor laser diode? This is only big news if it is as long as LEDs. Anyone know?

IB

I'm not sure why you would want an optical fiber coupling to do a diode laser projector. You also wouldn't want white light. The Nichia device is pretty nifty, but I don't see that it's relevant at all to video projection. On the plus side, laser light is polarized, so it's automatically twice as efficient for LCD/LCOS. Coupled with the ultra-narrow beam angle, you'd only need a fraction of the generated light to get the same brightness out of the projector.

Originally posted by scoby
I'm not sure why you would want an optical fiber coupling to do a diode laser projector. You also wouldn't want white light. The Nichia device is pretty nifty, but I don't see that it's relevant at all to video projection. On the plus side, laser light is polarized, so it's automatically twice as efficient for LCD/LCOS. Coupled with the ultra-narrow beam angle, you'd only need a fraction of the generated light to get the same brightness out of the projector.

Boy, you sure contradicted yourself on that post. I am not sure which side of your brain won the argument.

The fiber coupling device is optional and might be of use for very powerful fixed installation projectors to keep heat away from the other parts. You could have two boxes, one the projector and the other the light source. It would also allow the use of multiple diode lasers per LCD, LCOS, or DLP chip.

From my read, I would guess they could manufacture them to produce different colors.

The question is, for those who understand the numbers, is it bright enough for HT use at current published specs?

IB

I just did a search for diode laser life expectancy and found designs with 10,000 hour, 25,000 hour, and 100,000 hour life expectancy. So longevity depends on the individual design.

IB

Use a multi-fiber coupler with 10 lasers and you have a cool product to replace PJ bulbs. Use 40 and you have a light cannon. Couple into a rectangular fiber with 16:9 output and it fits the form factor of the image.

Lots of possibilities here. Since the collimation is great, less scattered light and high CR. Huge dynamic range. Pulsed mode usually is more efficient. Pulse width modulation can be used for high linearity.

Inky blacks -

Last I had heard about blue/white laser diode life expectancies, that was one of the core problems to be solved to get it ready for DVDs, etc. With the higher light output, that could be even more an issue, but I don't know anything solid to back that up.

The fact that Nichia is talking about using them in the later half of 2005 for HID lighting is somewhat reassuring, though. How many hours is considered acceptable there?

-RandomDave

did I missinterpret something? "Head with a diameter of 1.25 mm radiates a 50 lm beam"

at 50 lumens you will need a lot more then 1,3,10 or 40 for decent light for a real FP

Originally posted by AnthonyP
did I missinterpret something? "Head with a diameter of 1.25 mm radiates a 50 lm beam"

at 50 lumens you will need a lot more then 1,3,10 or 40 for decent light for a real FP

So what does "10,000,000 cd/m2" mean? How could it go from that big number to 50 lumens?

That is why I asked for a pro analysis of the numbers here, because I do not know what they mean.

IB

don't know, but it is light/area, I don't know if it means it can light up the area. The same way that a cheetah can run 114km/h but cannot run 114km in an hour (it can only run for a few minutes at that speed) or an ant can lift 3x its weight (but an ants weight is not much), it might be a trick of the numbers where it is so small that he multiplicative effect makes it look big. Also don't forget 1000mm=1m so 1,000,000mm2=1m2 and lasers tend to be uni directional, so if you had an array 800x800 of them (to fill out a m2) @50 lumens each gives you 32k lumens in total

Originally posted by inky blacks
So what does "10,000,000 cd/m2" mean? How could it go from that big number to 50 lumens?

That is why I asked for a pro analysis of the numbers here, because I do not know what they mean.

IB

Actually, the math isn't that hard. The fibre has a radius of 1.25mm, which gives a total of 3.14159*1.25^2 or about 5 mm^2 of total area. Since 1 m^2 = 1,000,000 mm^2, you need about 200,000 fibres to reach 1 m^2. So just multiply 50 lumens * 200,000 gives you 10,000,000 lumens/m^2, which is the same as 10,000,000 cd/m^2.

Assuming 20% optical efficiency, you would need 100 of these to build a 1000 ANSI lumen PJ. (I am using a low optical officiency number because this device emits white light. If it were built in R,G,B flavors you could assume a much higher optical efficiency)

Mike

3.14159*1.25^2 or about 5 mm^2 of total area
1.25 was the diameter not the radius

"Assuming 20% optical efficiency, you would need 100 of these to build a 1000 ANSI lumen PJ."

Sounds like we are still a long way from a practical LED or LED laser based projector that is bright enough to compete with bulbs.

IB

well this is closer, assuming you can put them in a bundle it should be less then10x10 for square or 13x8 to be closer to 16:9

at 13x1.25= 16.25mm=1.625cm=.6" what is the size of a DLP/LCD chip?

on the other hand I would suppose you would need to equalize the output over the whole area

Originally posted by inky blacks
The fiber coupling device is optional and might be of use for very powerful fixed installation projectors to keep heat away from the other parts. You could have two boxes, one the projector and the other the light source. It would also allow the use of multiple diode lasers per LCD, LCOS, or DLP chip.

The fiber coupling is still superfluous, and would make the system less efficient. You actually need to make the beam larger to illuminate the microdisplay. The lasers would need to be coupled to a color mixing light pipe to make a larger beam. Putting a fiber in between the two simply increases complexity and would waste light. You could probably design some hypothetical system in which it makes sense, but it really doesn't have much application in video projection.

"Sounds like we are still a long way from a practical LED or LED laser based projector that is bright enough to compete with bulbs."

I said this in another thread but it bears repeating:

There will not be a home theater-class projector with LED lighting for a good 5 years -- perhaps longer.

I believe you.

IB

Originally posted by rogo
There will not be a home theater-class projector with LED lighting for a good 5 years -- perhaps longer.
Do you know something we dont? I'm almost positive that statement is incorrect.

the simple fact that techs take a long time to go from thought to production (especially new stuff, the more drastic the difference the more time it takes), LEDs are no where near bright enough

"Do you know something we dont? I'm almost positive that statement is incorrect."

Well, for openers, I was given that timeframe by a source within TI. Secondly, Anthony's point is 100% right on -- there is an adoption curve even when the technology is ready -- and it isn't. Third, Lumileds / Luxeon is doing a great job, but has consistently been behind on hitting their roadmap dates -- I'm not sure anyone is moving faster than they are.

This technology becomes real some day. But 5 or more years for a home-theater class projector really sounds right. Consider that if the existing (are they shipping yet?) LED projector doubled in brightness a la Moore's Law, it'd be at least 4 cycles before it was home-theater class. That's 6 years.

(It's a 20-something lumen projector. Even if it were 40 -- and it isn't -- you'd need to go 80 --> 160 --> 320 before you're in the ballpark and that's still 4 1/2 years before you can talk about it. 5 or more years is right.)

Epson announced that it had succeeded in developing a prototype postcard-sized mini-projector using an LED light source. With a footprint of just 13.8 by 10.3 centimeters (just smaller than a sheet of A6 paper) and a slender profile, the 500-gram prototype can fit easily into the palm of your hand. The mini-projector can be viewed at first hand by visitors to the IFA trade show to be held in Berlin, Germany, from September 2 to 7.

Although the company has no immediate plans to market the mini-projector, company representatives believes that the prototype demonstrates just how compact mobile 3LCD projectors could one day become. "Projector using 3LCD technology already have advantages in terms of bright, natural images that are easy on the eyes," said Koichi Kubota, general manager of projector marketing at Epson. "This development is yet another example showing the potential of Epson projectors and Epson projector technology." With 11.3% of the share for front projectors worldwide in fiscal 2004*, Epson's popular range of projectors for education, business and home entertainment make the company the global market leader.

In addition to allowing ever more compact design, LED light sources provide several advantages over conventional lamps including immediate projection readiness, a long running time, and swift switch-off. The use of an LED light source in a projector is a first for 3LCD.

The current development is the latest in a long series of technical breakthroughs for Epson projectors. One of the very first companies to enter the projector market, Epson has stayed ahead of its competition by continually providing features and technologies that offer users real benefits. Recent developments include Crystal Clear Fine (C2 Fine) technology that dramatically enhances aperture ratios, definition, and image quality to enable the development of 3LCD projection TVs offering an even more realistic viewing experience.

The company will continue to place top priority on developing market leading projection projects for a wide variety of applications and locations.

http://forum.ecoustics.com/bbs/messages/10381/158740.jpg

cool, did not know Epson was working on one. But still does not answer the brightness issue.

Since they don't have any plans to produce it -- unlike the baby DLPs that are already shipping -- it's hard to worry about the brightness issue.

I think brightness is important. The whole discussion is when will we have LED based projectors for our rooms.

Since they don't have any plans to produce it -- unlike the baby DLPs that are already shipping -- it's hard to worry about the brightness issue.


That reminds me,what ever happened to that little tiny Infocus that fit in the palm of your hand from about a year ago..do any of these things ever materialize & make it to market?

Alan, i don't know when Infocus start to sell pocket projector, but Mitsubishi promised their LED DLP™ Projector will be available in the fourth quarter of 2005.
http://www.mitsubishi-presentations.com/proj_pocket.asp

Mitsubishi Pocket-Projector PT-10 im Cine4Home Teststudio!!!

http://cine4home.de/tests/projektoren/MitsuPocketPro/PocketProjectorzens.htm

http://cine4home.de/tests/projektoren/MitsuPocketPro/Bild3.jpg

vsv

Thanks for the pic. Thats smaller then the infocus. Id buy one just for giggles.

I did some research and none of these are shipping yet. They were announce and demode a year ago, sure does take these guys forever to get something to market.

All the more reason, Alan, why LEDs ain't replacing lamps anytime soon.

If this baby ships in end 2005 and performance doubles every 18 months (Moore's Law-like), we culd be 7 years away from achieving lamp-like results -- or more.

Toshiba Prototypes Compact Projector Using LED Light Source

Toshiba displayed a prototype compact projector weighing about 500g at "WPC EXPO 2005," a PC and digital electronics trade show held in Japan these days.

The digital light processing (DLP) projector's key feature is a light source using light-emitting diodes (LED). Toshiba reduced projector size and weight by introducing red (R), green (G) and blue (B) LEDs as a light source, which was high-pressure mercury vapor lamps combined with a color wheel in its current compact projectors. The weight is about half that of the company's current most compact product. The dimensions are 136 x 100 x 55 mm. Toshiba also claims that it has succeeded in reducing power consumption to 15 W, lower than a 1/10.

The company plans to release the projector onto the market in January 2006. The product will be packed with a Li-ion secondary battery pack (250 g), a dedicated screen for image projection and a bag, which can also be used to carry a notebook PC. Pricing is not fixed, but street pricing is expected to be around 100,000 Yen (US $864).

Details of the embedded LEDs are not specified, but a company spokesperson explained, "We employed a product boasting the market's highest level luminance." However, due to the first priority given to size reduction, the number of LEDs is limited to two green LEDs, one blue LED and one red LED. This results in a poor image luminance of only about 1/100 the current product's 1,500 lm, which the spokesperson says "is not sufficient to project images to other screens available in the market." Consumers therefore need to use the dedicated screen packed with the projector.
http://www.digitimes.com/NewsShow/20050907PR209_files/image002.jpg

So 15 lumen it is.

and comes with a napkin :)

Yeah but it's a big nice linen napkin, like from a fancy restaurant, and it comes in a wineglass.

BB

Yeah but it's a big nice linen napkin, like from a fancy restaurant, and it comes in a wineglass.

I was making fun of the size of the screen

I wonder what the included screen technology is like...high gain? I keep waiting for some miracle high-gain "black" screen to help "regular" projectors as well.

I was making fun of the size of the screen

Well, yeah, so was I. I am just very sparing in my use of :) 's

BB

Premier PD-S682 Mini DLP Projector

http://www.premierimage.com.tw/premiere/003/images/PRJ/PDS682.jpg

Product Type DLP Projector Premier Model PD-S682

Display Type 0.55" SVGA

Resolution (Pixels) 800x600

Uniformity 60%

Lens Fixed Zoom

Contrast ratio 300:1

Screen Size 12 - 60 inches

Lamp Life 5000 hours

Color 16.7 million (24 bits)

Keystone Correction Vertical: +/- 15 degrees

PIP N/A

Audio System 0.3W x 1

Video Input PAL, NTSC, SECAM, HDTV

Computer Input VGA(resized), SVGA,XGA(resized), SXGA(resized)
(480P,576P,720P,1080i)

Input Source VGA, S-Video, Composite video SD card slot

EMI & Safety CE, FCC B, VCCI, ICES-003, C-Tick CCC, UL, cUL, PSE J60950

Sound Noise 30dBA

Power Requirement 100 - 220v, 50 - 60Hz

Power Consumption 19W

Dimension (WxDxH) 121 x 99 x 47 mm

Wieght 0.5Kg

http://www.premierimage.com.tw/premiere/003/project/003_PDS682.htm

Nanoprojector built for portable handheld devices (http://www.videsignline.com/products/175803369;jsessionid=3IUR04XA2BX20QSNDBCCKHSCJUMEKJVN)
London — Microdisplays specialist Kopin Corp. has teamed with Israeli group ExPlay Ltd. to develop a nanoprojector for portable, handheld devices.

Under the $2.2 million program, partially funded by the BIRD Foundation, Kopin and ExPlay (Herzelia) aim to come up with a projection engine with target optical efficiencies nearly 10 times higher than those currently available.

The companies say they plan to introduce a working projection engine during the first half.

BIRD (Taunton, Mass.) is an acronym for Israel-U.S. Binational Industrial Research and Development. The foundation's mission is to stimulate, promote and support industrial R&D of mutual benefit to both countries.

"A key requirement for a nanoprojector is high brightness at low power consumption," said Dr. Bor-Yeu Tsaur, Kopin's executive vice president of Display Operations. "We have engineered the display pixel technology to increase the effective optical aperture and transmission, which significantly increases optical efficiency. We believe our proprietary compact, highly transmissive microdisplay combined with a unique optical-engine technology from ExPlay should enable an ultracompact nanoprojector."

Ease of integration
Key to the success of the development, according to Golan Manor, ExPlay's vice president of technical marketing, is "a tight combination of a high-transmission microdisplay and a specially designed optical engine in an easy-to-integrate package."

Dr. John Fan, Kopin's president and CEO, said: "With burgeoning markets in mobile video, portable gaming and handheld devices such as PDAs and video cellular phones, there will be a significant demand for high-resolution microdisplay systems to complement these products. We believe a cost-effective, high-performance nanoprojector will be a reality in the near future."

Best New Enabling Technology

Luminus PhlatLight LEDs
High-brightness LED technology has been evolving rapidly in the last few years, but at CES, stealth company Luminus Devices (Woburn, MA) (www.luminus.com) put a new stake in the high-brightness ground. Using photonic lattice technology originally developed at MIT, the company has created LEDs that attain brightness levels that are ten times those of competitors.

How do they do this? It seems the secret sauces are in the LED device design, the photonic lattice layer (which is added on top of the LED device), and a good thermal management system. The advantage for projection systems is clear: more light out of the projection lens. Others agree. At CES all five public demonstrations of LED-based rear-projection TVs were based on LEDs from Luminus.

Luminus is offering two standard LED products: one with an 8.5mm2 die and the second with 18mm2. These two products are optimized for 0.70-0.75 inch and 0.80-0.85 inch microdisplays, respectively, and can be used with DLP, LCOS or 3LCD projection systems.
http://insightmedia.info/images/Luminus.jpg

LUMINUS DEVICES’ PHLATLIGHT™ CHIPSET USED IN
SAMSUNG’S AWARD WINNING HL-S5679W 56-inch DLP HDTV

New Samsung DLP-Based Rear-Projection TV Wins CNET Best of 2006 Award at CES 2006
http://www.luminus.com/content42.html

Look also treads in RPTV forum:

The survival of rptvs: leds and lasers
http://www.avsforum.com/avs-vb/showthread.php?t=636401

Akai to ship 1080P LED DLP for 1799.99 (46inch) and 2199.99 (52 inch)?
http://www.avsforum.com/avs-vb/showthread.php?t=627962

Info on new Samsung LED sets?
http://www.avsforum.com/avs-vb/showthread.php?t=652150

vsv,

the phlatlight look really good! Do you know what sort of light output power it getting? (lumen, or lm/W efficiency)?

Led Projector lumens, see the following link:

http://www.zeiss.de/C12567BE0045DA85/?Open

and select "Digital Projection TVs (MD)"
and then "LED Projection"

Hi RichardB,

The 200lm is suppose the on-screen lumen value. There should have some optical loses in between LED source and on-screen value - normally about 75%.

So, the light source probably at 800lm.

Thanks for the links - is that using phlatlight tech?

I do not know for sure that zeiss is using phlatlight, but everyone who has announced an LED RPTV is using phlatlight and zeiss is one of the main suppliers of microdisplay engines to the industry.

Anybody have any idea how the phlatlight LED chips is processed or structured? Cheers

Toshiba FF1 LED projector review (German THG) (http://www.de.tomshardware.com/video/20060323/index.html)
http://www.de.tomshardware.com/video/20060323/images/toshiba_8.jpg

Hi RichardB,

The 200lm is suppose the on-screen lumen value. There should have some optical loses in between LED source and on-screen value - normally about 75%.

So, the light source probably at 800lm.

Thanks for the links - is that using phlatlight tech?

How do you possbily get 800 lumens at the source? The Zeiss page clearly states that the engine is 200 lumens. This is preceisly why these LED devices use high gain screens (>3x) because there isn't enough power.

Sony Develops Handheld LED Projector

The projector uses 0.62 inch 800 x 600 transmissive LCDs as display devices. A total of 14 LEDs are used, including four red, four blue and six green diodes. The brightness of the LED reaches 50 lm. The power consumptions required for the LED unit and the entire projector are 20 and 30 W, respectively. A wide color gamut of 120% NTSC can be achieved. (http://techon.nikkeibp.co.jp/english/NEWS_EN/20060613/118113/)

http://techon.nikkeibp.co.jp/english/NEWS_EN/20060613/118113/sony3.jpg

http://techon.nikkeibp.co.jp/english/NEWS_EN/20060613/118113/

cool info

OK guys it has been a while but here is a question...
go check out the K2 LED at www.lumileds.com, they have a white LED with 100 lumens at $3.45 each, a 120 lumen at ~$9.
I have a Sanyo PLV70 and it puts out a spec'ed 2200 lumens, that would be 22 of the lower output K2. For a cost of $75.90, I could theoretically build an array that would fit in the area of my existing lamp (each is < 1cm square) and would have a 'unlimited' lifetime compared the the current engine. The lumens are spec'ed in relation to the drive current (1 A in this case) and the typical forward voltage is 3.42 V per. Wired in a series string (thus just 1 A current), the total V would be ~76V. I am not sure what the existing drive circuit looks like on my system (probably a very large step-up in voltage), but I could imagine taking line voltage and running on half of the power cycle I could get damn close to 2200 lumens on 1A and not have to buy another lamp.
What do you think? Anyone want to talk about a business model for a new replacement 'lamp' for old projectors?

I've been waiting for someone to say something like this for a while. Why not?

I think that one question would be what the light-spectrum of that "white" LED light is like. It may not compare favorably for high-fidelity RGB applications.

You're forgetting one thing.

The 2200 lumens is the output lumens, not the input lumens. In order to get 2200 lumens out of your PJ you'd need to put in at least 4500 lumens. (For an LCD, at least 6600 lumens for a DLP.)

And don't forget about the etendue!

Mike

Let me know when you can cram all those LEDs down into a point source the size of the arc in the UHP lamp in the PLV 70.so I can do it in mine too. Because that is the relevant part of the "area of the existing lamp", a ball of plasma on the order of a millimeter across.

Étendue is an implacable opponent.

BB

Putting many LEDs in as a light source is defintely the wrong way to do it and just a band-aid till manufacturers can make an LED die the size of the imager and luminocity in the many hundreds of lumens of even thousands.
I'm waiting for those days.

Also, 'white' LEDs (they're actually Blue) is the wrong way to go at it.
The only way to have an efficient LED system is to have RGB LEDs.
This would be especially beneficial to single chip DLP.
No more colowheel.

Unfortunately we will still be talking about this 5 years from now wondering "wheres the beef" :)

Now, now, Alan.
Everybody knows in 5 years we'll all have laser projectors scanning a 3D movie directly into our retinas.
No need for stinkin' LEDs or plasmas or LCDs, LCoS, DLP etc. etc. :D

"In order to get 2200 lumens out of your PJ you'd need to put in at least 4500 lumens."

I think it's more like 10k - 20kL; IIRC end-to-end optical system efdficiency for pj's is like from 10-20%.

Also, 'white' LEDs (they're actually Blue) is the wrong way to go at it.
The only way to have an efficient LED system is to have RGB LEDs.
This would be especially beneficial to single chip DLP.
No more colowheel.

it will be extremely beneficial for all projectors. and agree, white LED's don't make any sense what so ever.

Putting many LEDs in as a light source is defintely the wrong way to do it and just a band-aid till manufacturers can make an LED die the size of the imager and luminocity in the many hundreds of lumens of even thousands.
I'm waiting for those days.

I don't know. That is why I found that Sony LCD info so interesting compared to all the DLP projectors. It is the first multi LED/colour projector. LEDs are no where near powerful enough to become real projectors. if we can use 3-6 of them the demand per LED decreases by a lot (I am guessing not a factor of 3 or 6, but still a lot)

I think it's more like 10k - 20kL; IIRC end-to-end optical system efdficiency for pj's is like from 10-20%.


but single colour LEDs will help a lot

You're forgetting one thing.

The 2200 lumens is the output lumens, not the input lumens. In order to get 2200 lumens out of your PJ you'd need to put in at least 4500 lumens. (For an LCD, at least 6600 lumens for a DLP.)

And don't forget about the etendue!

Mike

However, for many technologies (single chip DLP) that's due to throwing away 2/3rds of the light via filters. Seperate R, G, and B light sources that can be pulsed, such as these, would avoid much of that loss.

In LCD and LCoS, the light is split via prisms, but I don't know how much loss occurs there. I believe 50% of the light in these technologies is lost due to polariers, as well.

Also, for the OP, at least in the sequential color designs (single-chip-DLP), Wigggles has suggested that the LED arrays can be over driven frm a current standoint, as their duty-cycle is less than 100%, so you would ostensibly need fewer LED's in the array.

Etendue, however.... [sigh]...

Now, now, Alan.
Everybody knows in 5 years we'll all have laser projectors scanning a 3D movie directly into our retinas.
No need for stinkin' LEDs or plasmas or LCDs, LCoS, DLP etc. etc. :D

Funny you should say that. Saw a demo of a miniature laser-based PJ last week. Not intended for intra-ocular use though, just small portable apps.

BB

Well Brandon?
How did it look?
What was the 'res' on that puppy?
Could it light up a 20-40" wall screen for gaming?
Sounds fascinating.

Looked really really nice, incredible color.
XGA
ten lumens, so "no".

It is definitely a cool product. No one seemed inerested though, even Ohlson didn't bite, which actually made me wonder if he's OK.

http://www.avsforum.com/avs-vb/showthread.php?t=695837

BB

However, for many technologies (single chip DLP) that's due to throwing away 2/3rds of the light via filters.

much more then 2/3. Have you ever seen a rainbow (as in the rain and not on the screen) the bulb is not only sending out a thin range of RGB, it is sending RGB that the filters will not let through, it is sending every possible colour (more or less).

much more then 2/3. Have you ever seen a rainbow (as in the rain and not on the screen) the bulb is not only sending out a thin range of RGB, it is sending RGB that the filters will not let through, it is sending every possible colour (more or less).

Fair enough, but I was contrasting the display types (you left out the part where I talked about prisms in 3-panel displays) in their light loss.

In all the solid-state technolgy types, filtering the lamp to get RGB must happen.

But it's certainly true that in the initial LED discussion, the overall lumens that a arc-type lamp must generate certainly is far greater due tp the point you mentioned.

So, does anybody know how efficient the prism designs are?

Did not mean to imply that had to do with DLP or colour wheel. The fact is most of the light is thrown out because it is the wrong wavelength (colour). RGB LED instead of white light will help with this. And since LEDs don't age in the same way as bulbs you can go multisource (colour). single chip DLP also has the added issue, like you mentioned, that it is sequential, so if we assume the amount is for R,G and B from the prism and the filter then the DLP will start off with around 1/3 the light. LEDs could help with that as well because LEDs can be run brighter for shorter periods of time.

Guys, what yours thoughts about LED light engine used in DLP RPTV Samsung HLS-5679W (http://www.avsforum.com/avs-vb/showthread.php?t=709624&page=1&pp=30)?
If these 18 PhlatLight LEDs (6 red+6 green+6 blue) can produce 500 Lm, why impossible to create 1080p front projector ?

I found this over at Sanyo

LOSE THE LAMP?

The day is coming when your projector might not use the tried-and-true short-arc lamp - at least, not if several alternative technologies are successful in coming to market. One of those technologies employs discrete red, green, and blue lasers to create full-color images.

Lasers have been around for years. Perhaps you've been to a planetarium laser show, set to rock music. Or you've seen a laser light show spectacular at a theme park. (Surely you've used a laser pointer at one time or another?) But it's only recently that small, efficient lasers have made an appearance. Now, some manufacturers are showing them in projection TV sets.

Unlike the light from a short-arc projection lamp, laser light is coherent, or very tightly focused. A laser beam hardly diffuses at all as it travels over hundreds and even thousands of feet. As a result, a low-power diode laser can provide a beam of light smaller than a millimeter in diameter that is nearly as bright miles away as it was at the source!

In a projector, coherent light is not usable. So the beams from red, green, and blue lasers must be diffused, or softened, before they are mixed to create colors. Diffusing laser light also reduces speckle, which appears as a distracting grainy pattern on laser images.

The advantages of using lasers are several. For one thing, many optical components in a projector can be eliminated, including condensers, light integrators, and polarizers. In fact, the dichroic color filters can also be removed, as the pure laser colors are of near-equal intensity for ideal color shading.

Lasers are also instant on, instant off devices with a life expectancy of over 50,000 hours. With economies of scale in manufacturing, laser light engines could be manufactured for ½ to 1/3 the cost of a new short-arc lamp.

There are still plenty of operational and manufacturing issues to resolve before the first laser projectors hit the shelves so don't look for them any time soon. But there are real pressures to find replacements for short-arc projection lamps, not the least of which are tighter regulations on the use of potentially toxic metals (including mercury) by the European Union, starting this year. Could lasers be a practical alternative?

A BRIGHT IDEA


Yet another way to illuminate an image is to employ arrays of light-emitting diodes (LEDs). LEDs have also been in use for several decades and are the mainstay of super-bright outdoor signs in places like Times Square and Las Vegas.

Now, some manufacturers are harnessing them to rear-projection TV technology. Like lasers, LEDs are instant on, instant off devices with long operating cycles. They emit pure colors of red, green, and blue (also yellow and white) and are diffuse lighting devices.

By themselves, LEDs are not particularly energy-efficient. In fact, an LED light engine of equivalent brightness to a short-arc projection lamp will consume much more power- that is, unless the LEDs are pulsed at a very fast rate in switched-mode operation. And that's where LEDs can take the lead over short-arc lamps.

SANYO showed a prototype 52-inch rear-projection LCD TV (with 1920x1080 resolution) and an LED light engine at CES 2006. The LED "chips" produced white light, the color temperature of which was set by changing the drive to the individual red, green, and blue segments in each LED chip.

Colors were clean and saturated, and the images produced were comparable in brightness and contrast to any other rear-projection TVs equipped with short-arc lamps. Other companies had similar demonstrations of LED rear projection, and it's probably safe to say you'll see one or two models for sale in 2007.

As for front projection, short-arc lamps are still the way to go - for now. LED arrays with enough energy to light up a large front screen are still very expensive, need lots of power, and give off quite a bit of heat. But time will tell…

"With economies of scale in manufacturing, laser light engines could be manufactured for ½ to 1/3 the cost of a new short-arc lamp."

Since when?

"There are still plenty of operational and manufacturing issues to resolve before the first laser projectors hit the shelves so don't look for them any time soon."

That's more like it :)

Go to C. Crane Company and see their page on LED light bulbs at:

http://www.ccrane.com/lights/led-light-bulbs/index.aspx

At the bottom of the page they have a comparison of whole life cost of LED bulbs vs. incandescent bulbs. According to their reckoning, LED bulbs are cost effective now, despite the high initial price. :) :eek: :)

What do you think? Is their math real or is it fudged? :rolleyes: I remember a recent article where they found a way to increase LED light output many times. Imagine these bulbs with this newer technology added! With increases in efficiency and mass production, the cost-benifit ratio could be incredible! :D

I use florescent bulbs, but the light is a bit cold and they cause radio interference and don't dim well. LED should be as good or better than incandescent in those regards and a hell of allot more efficient. They would make great lighting for home theaters as well. If you use 100 light bulbs in your home, it would cost about $3,600. to make them all LED. But your electric bill would go down for 30 years as the LEDs might last that long, depending on use.

Comments?

IB

"According to their reckoning, LED bulbs are cost effective now"

That may well be true for diffuse illumination, but not for the concentrated light needed in a pj; entendue, as has been mentioned in this thread already.

I know. I was talking about home lighting. For projectors I think you need lasers. In that arena the problem is lowering cost and size. If they can project a spot on the moon with a laser, they can make a projector out of three of them.

IB

New version of Samsung Pocket Imager demonstrated on IFA2006.
A small LED based 50 lumen 1 kilo projector.

DivX HD 68 MB
http://media.divx.com/charbax/ifa2006/IFA2006_SamsungPocketImager.avi

LG introduced a new projector into Korea today with the same design of their popular cellular phone “chocolate.” This new LED projector offers a HDMI and VGA plugs and uses a single DLP chip. While details are pretty sparse, it looks like to be an interesting little projector to compete with Toshiba’s TDP-FF1AU and Mitsubishi’s PK20 in the portable LED projector market.

http://image.aving.net/img/2006/10/20/20061020164653.jpg


LG to reveal a new chocolate projector following the chocolate phone (http://aving.net/usa/news/default.asp?mode=read&c_num=26957&c_code=03&sp_code=0&btb_num=101)

Light Blue Optics has developed a unique, patented laser projection technology,that exploits the principles of diffraction to project full-colour, real-time video images.

"Our projection technology uses laser light sources in conjunction with a phase modulating liquid crystal on silicon (LCOS) microdisplay on which a diffraction pattern, calculated from the desired image, is displayed. When the microdisplay is illuminated by coherent laser light, the desired image is projected."

http://www.lightblueoptics.com/technology.htm

http://www.lightblueoptics.com/diagram_340.jpg

Well, it looks like my soon to be received RS1/HD1(in all black PLEASE) is out dated already! :eek:

LG Electronics’ Ultra Mobile Projector is in the “pocket projector” class having a very compact size and the ability to use battery power. LG claims its Ultra Mobile Projector is the brightest commercially available pocket projector and delivers 100 Ansi lumens thanks to Luminus Devices’ PhlatLight PT39 chipset. Typical pocket projectors have a brightness of only 15 - 30 lumens, so the Ultra Mobile Projector is many times brighter and can be used in daylight with a large image that has good color and image quality. Unlike large projectors, pocket projectors like the Ultra Mobile Projector use LEDs that enable a compact size, very long lifetimes and the capability to be turned on instantly.

http://www.luminus.com/content102.html

Samsung SPP310MEMX use newest PhlatLight LED's ? http://www.phlatlight.com/home.php
http://www.samsung.com/Products/UltraPortableProjector/PocketImager/SPP310MEMXAA.asp?page=Specifications

SpatiaLight, a developer and manufacturer of high-resolution liquid crystal on silicon (LCOS) microdisplays for high-definition TVs (HDTVs), has entered into a memorandum of understanding (MOU) with Foreal Spectrum (Foreal) for the development and marketing of a 1,920×1,080 LED-based LCOS light engine. The light engine will primarily be marketed to OEM's of rear-projection TVs (RPTVs) and front projectors.

Foreal and SpatiaLight displayed this proprietary light engine in January at SpatiaLight's suite in the MGM Grand Hotel during the CES 2007. The light engine employs SpatiaLight's T-3, 1,920×1,080 imagers and is powered by a long life, solid-state LED light source rather than the standard high-pressure mercury arc lamp.

SpatiaLight and Foreal believe that this LED light source is a major breakthrough for LCOS technology because it removes the "lamp lifetime" issue for TV manufacturers and the new LED engine will allow for thin form factor LCOS RPTVs. A typical 60-inch TV based on this new light engine will be fewer than ten inches deep in the near future.

This solid-state light source dramatically improves light engine lifetime. Future generations of light engines can incorporate smaller, lower cost imagers as product categories are expanded and markets for these products grow.

This lower-cost LED/LCOS technology solution is currently available for incorporation into RPTV models, as opposed to other new light engine technology formats including laser diode powered light engines, which are not currently economically feasible for mass produced, high brightness applications such as projection TV.

Foreal's new, fully customizable LED light modules and engines provide maximum brightness for the small emitting areas required for RPTV and pocket projectors, in addition to semiconductor and biomedical instrumentation. The benefits are numerous when compared to traditional light engines using standard arc lamps including: enhanced color gamut and uniformity, reduced production and maintenance costs, compact size and reduced weight. LEDs also feature instant on/off capability for minimal heat, longer lifetime and improved safety.

If you look up SpatiaLight's stock price, you'll see that there's a remote chance any new products will available from them.

"the new LED engine will allow for thin form factor LCOS RPTVs."

What does the light source have to do with form gactor, which is dominated by the length of the optical path and mirror required to form the image?

"the new LED engine will allow for thin form factor LCOS RPTVs."

What does the light source have to do with form factor, which is dominated by the length of the optical path and mirror required to form the image?


My guess is that the LED themselves are so much smaller than the old bulbs and are so concentrated a light source, that a few inches can be shaved off the total light engine length. The focal length may be the same or slightly shorter, but certainly the housing for the bulb is gone, all the fancy reflection devices are gone, all the big spaces around the bulb you need for cooling are gone, and you have tiny high powered solid state LEDs focused quite intensely on the LCOS chips. A 5" savings of space would not be a surprise. Even the old type bulb RPTVs are quite thin theses days. LEDS just makes them a few inches thinner.

For myself, I want a laser, not a LED.

IB

Makes sense, thanks

We've got one of the Samsungs, along with a bunch of the little Mitsubishi's. The Samsung is much brighter, a bit over 40 lumens.

BB

Explay has developed the world's smallest projector, a revolutionary nano-projector engine small enough to fit inside your pocket or be embedded in your mobile device, allowing you to truly enjoy the big picture wherever you are.

With an experienced multi-disciplinary team of experts in electro-optics, polymer optics, beam shaping, opto-mechanics and analog and digital ASIC design Explay is changing this industry picture by providing projection solutions that can harvest the full potential of mobile devices.

ExPlay’s revolutionary laser based projection technology enables high-resolution images 20 times larger than the mobile device itself. Its unique battery-operated, nano-projector ensures an eye-safe, always focused superior quality, powerful projected image, elements essential for frequent usage by mobile product consumers.

Using the combined power of an innovative light source, an enhanced image modulator and a proprietary ASIC, Explay provides a complete optic and electronic projector engine solution for simple and glueless integration into third party products.

http://www.cybertheater.com/wp-content/uploads/2007/01/projector.jpg

OnDeGo Nano-Projector Engine

Explay's first generation nano-projector engine module aims at both consumer and business markets. It is a projection engine that can either be integrated into a standalone pocket projector connected (through a cable or wireless connection) to different handheld electronic devices or it can be integrated into the mobile device. Explay’s OnDeGo products will support applications with projected screen sizes from 7" up to 30".

http://www.explay.co.il/images/stories/handengine-01.jpg

Explay Ltd. announced that it will present and demonstrate its new version of the Companion Nano-Projector at a press conference scheduled for May 22, 2007 at 11:35 a.m. in Room 101A at the Society for Information Display International Symposium, Seminar and Exhibition 2007 at the Long Beach Convention Center in Long Beach, California. Explay will also be exhibiting at SID 2007 at booth number (1961).

“Our companion projector has experienced a dynamic evolution in the past year. Like previous models, the new fully operational battery operated companion is eye safe and delivers projections that are always focused. Today, we have a working mobile prototype that provides unrivaled competitive deliverables for the mobile lifestyle. We are looking forward to showing you what we mean,” said CEO Daniel Oleiski.

To schedule an interview or a business appointment with Explay management, please contact media liaison Marjie Hadad at marjie_h@explay.co.ilThis email address is being protected from spam bots, you need Javascript enabled to view it or call +972-54-536-5220.

http://www.explay.co.il/

"The new Phlatlight PT120 LED chipset has an emitting area of 12 mm2. The red chip emits 660 lumens, the green 1550 lumens, and the blue 250 lumens."

Do you think is really low numbers for a front projector?

"Do you think is really low numbers for a front projector?"

It's about a quarter of what a typical UHP lamp puts out, but it depends on how much larger a percentage of the light makes it to the screen than a conventional pj.

"The new Phlatlight PT120 LED chipset has an emitting area of 12 mm2. The red chip emits 660 lumens, the green 1550 lumens, and the blue 250 lumens."

Do you think is really low numbers for a front projector?

That's actually pretty good.
The bottleneck seems to be the BLUE LED.

In order to get D65 white from RGB LEDs we need:

43.1% RED, 33.5% GREEN, 23.4%BLUE

So with 250 lumen of Blue
Red becomes 460 lumens
and Green becomes 358 lumens.

That adds up to 1068 lumens at 100% efficiency.

A 3-DLP system has an efficiency of about 35% which means that the projector will have 373 lumens max.

That's not bright but it will only get brighter.

"A 3-DLP system has an efficiency of about 35% which means that the projector will have 373 lumens max."

That's pretty good.

But it seems that an LED system should easily exceed that, assuming the colors are near the proper primary colors.

There would be no losses from splitting and then recombining colors, nor from filtering.

I don't really know, but I'd guess that effciency would be at least double.

70% efficiency would be awesome.

We're talking very little cooling will be needed. Big savings right there and the reliability shoots up! Win-win.

"Do you think is really low numbers for a front projector?"

It's about a quarter of what a typical UHP lamp puts out, but it depends on how much larger a percentage of the light makes it to the screen than a conventional pj.

200W UHP bulb have 8000-10000Lm, but "with little help" of color wheel on the screen only 1/10 of bulbs light.

With PT120 and 0,7" DMD possible to get ~500Lm and a few more with new PT180 RGB LED optimised for 0,9" DMD.

"With PT120 and 0,7" DMD possible to get ~500Lm and a few more with new PT180 RGB LED optimised for 0,9" DMD."

That's fully competitive with todays' HT pj's; the JVC RS1, which is considered rather bright, is right around that.

"With PT120 and 0,7" DMD possible to get ~500Lm and a few more with new PT180 RGB LED optimised for 0,9" DMD."

That's fully competitive with todays' HT pj's; the JVC RS1, which is considered rather bright, is right around that.

Only facts:
1.PT180 RGB LED exist and optimised for 0,9" DMD
2.0,95" DMD is fullHD 1920x1080 and used for front projectors!
3. 500-700 Lm LEDDLP front projector is possible today :)

LED Light engine with 3 SXRD can be brighter and better if this be made by Canon :) ...

Well, this is what I'm waiting for.
Bring it on!!!

I have several flashlights that have Luxeon III bulbs in them. Basically the L3 is just a version of the 1W Luxeon that is able to be over driven. There is a significant blue tint to the Led when you over drive it.

All in all, I am a LED fanatic, so I really hope to see a decent LED based projector in the next couple of years.

With that current projector, sounds like all they need is one of Vutec's 9 gain screens :)


i want to see them use the x-cree edition leds, or even the p4 leds!
i have the lp M1 hunter w/ cree led and it can light up a building at night!

can't wait to see this used in the pj market

Please somebody help me ! i have optoma ep 732 projector i want disconect ballast and uhp bulb (bulb is brocken finish ) i dont want new i want change system light ( led is god idea ) but i must first eliminating uhp system. maby someone help me how?