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post #1 of 56 Old 10-14-2014, 04:09 PM - Thread Starter
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SMPTE Webinar: Laser-Illuminated Projection



SMPTE's latest emerging-technology webinar focused on laser-illuminated projection, a subject of particular interest to AVS videophiles.

Last week, I attended a webinar entitled "Laser Science and Laser Illuminated Projection" hosted by SMPTE (Society of Motion Picture and Television Engineers) and presented by Bill Beck, whose official title is The Laser Guy at Barco, one of the major suppliers of digital-cinema projectors. Bill's presentation applied mostly to commercial cinema, but laser illumination is quickly finding its way into consumer products, so it's highly relevant to the future of home-theater projection.

Types of Laser-Illuminated Projectors


He started by stating that commercial laser-illuminated projectors are now available using one of two basic technologies. The most direct approach uses separate red, green, and blue laser diodes to illuminate three imagers, most commonly DLP chips, so it's no surprise that this technology is called RGB. Barco, Christie, NEC, and others make RGB laser-illuminated projectors.

The other technology uses blue laser diodes to provide the blue light and to excite a phosphor to emit yellow light, which is then separated into red and green; this is often called blue laser-pumped phosphor (BPP) or laser hybrid. Companies making BPP projectors include Christie, Digital Projection, Epson, NEC, and Sony, though some of these products are intended for the consumer market.


BPP projectors use blue lasers to provide blue light and to stimulate a phosphor to glow yellow. RGB projectors use separate red, green, and blue lasers.

One of the biggest differences between RGB and BPP projectors is light output—RGB models can reach 60,000 lumens or more, while commercial BPP designs max out at about 6000 lumens. (As we know from CEDIA, Epson's LS10000 consumer-oriented BPP model is rated at a maximum of 1500 lumens.)

Laser Advantages

Compared to the xenon lamps used in most current commercial projectors, lasers offer many advantages. One of the most important is longevity—lasers have an effective lifetime of 10,000 to 100,000 hours with little decline in brightness per hour of use. By contrast, xenon lamps must be replaced every 500 to 1000 hours or so.


RGB laser-illuminated projectors lose only 20% of their brightness over 30,000 hours of use, while BPP projectors lose that much brightness after about 8000 hours and reach half brightness after about 20,000 hours. Meanwhile, xenon lamps lose half their brightness after only 500-1000 hours, requiring up to 60 replacements during the lifetime of a single RGB laser engine.

Another advantage of lasers over xenon lamps is higher efficiency in converting electrical power to light output. Lasers can produce 5-6 lumens per watt from the wall, while xenon lamps produce 2-5 lumens per watt. Typically, laser projectors can reduce power consumption by 30-50% over lamp-based models.

Even so, RGB projectors can be as much as 2-3 times brighter than xenon lamp-based projectors, in part because lasers exhibit a low etendue, which means the light spreads out slowly from the source, whereas the light from a xenon lamp is emitted in all directions at once and must be focused. In addition, a xenon lamp creates light in a small area called the arc, which creates a bright spot, leading to image-uniformity problems that lasers don't have.

Current laser-illuminated projectors can achieve a full-on/full-off contrast ratio of 2300-3000:1, which is right in line with the DCI (Digital Cinema Initiative) spec of 2000:1. However, with redesigned projector optics, Beck says that a contrast ratio of 10,000:1 is possible. Of course, the content must be mastered with high dynamic range, and displaying such content on a laser-illuminated projector typically results in lower optical efficiency and more speckle.

Laser Challenges

Finally, lasers can provide a range color gamuts, though this capability is not without some problems. For one thing, lasers emit light in a very narrow range of wavelengths—essentially a single wavelength. This is great for the BT.2020 color gamut, whose primaries are single-wavelength, but this also results in speckling, an artifact that imparts a grainy look to the image—and not in a good, "film grain-like" way.

Another problem with narrowband primaries is called observer metameric failure. Metamerism is the matching of apparent colors with different spectral distributions; in video, any color within the gamut of the display, regardless of its spectral curve, can be matched with a unique mixture of red, green, and blue, which forms the basis of trichromatic colorimetry. Colors that match in this way are called metamers.

Humans perceive color thanks to light-sensitive cells called cones that coat the inner surface of the retina at the back of the eyeball. There are three types of cones, which are sensitive to different ranges of wavelengths that can roughly be categorized into red, green, and blue. The range of wavelengths for each type of cone is very broad, and different combinations of wavelengths can produce equivalent responses and thus the same color sensation.

However, the proportion of long, medium, and short wavelength-sensitive cones, the precise profile of light sensitivity in each type of cone, and other factors differ from one person to the next, so we all see slightly different colors. With broadband primaries, such as those from a lamp, these differences are obscured, and most of us see the image as having the same colors. But with narrowband primaries, such as those from lasers, differences in color perception become more pronounced, and different viewers will see different colors, an effect called observer metameric failure (OMF).


Here we see the 709, P3, and 2020 color gamuts and some notes about them as they pertain to laser-illuminated projectors.


Potential solutions to the speckle and OMF problems include using several different laser wavelengths for each primary and broadening the bandwidth of each primary. The red, green, and blue curves in each graph represent the sensitivities of the corresponding cones in the human eye. In this graphic, FWHM stands for "full width at half maximum," a measure of bandwidth.

When it comes to 3D, Christie, Barco, and others are working on so-called 6-primary (6P) designs in which slightly different wavelengths for red, green, and blue are used for each eye in conjunction with Dolby/Infitec passive-3D glasses. Barco puts both sets of lasers in one chassis and quickly alternates between them, while Christie uses dual projectors so that both sets of primaries can be on the screen simultaneously. Either way, Beck claims that image quality and brightness are much better than lamp-based color-separation or polarization systems.

Laser-illuminated projectors have come a long way in the commercial-cinema world, and that progress is bound to migrate to consumer products, as illustrated by the Epson LS10000. This technology offers many advantages and a few challenges compared with conventional lamps, but it seems to me that lasers have the potential to supplant lamps in the future. I look forward to following any developments in this particular corner of videophilia, and of course, I will report what I learn right here on AVS.

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post #2 of 56 Old 10-14-2014, 04:14 PM
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Scott!! Timely article, thx so much.
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post #3 of 56 Old 10-14-2014, 04:25 PM
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Very good article and even though I am an ophthalmologist and have studied the retina and intracies of color vision perception I still can't understand how lasers can have much of a future in video projection since they emit a narrow spectrum usually a single wavelength of light. Yet at the same time there are millions of different colors of different wavelengths or hues. How can lasers reproduce each of these individual colors? I still don't understand how that is possible even though I have used a lot of lasers in my career in treatment of retinal diseases and after cataracts, etc.
I hope my asking this question doesn't reveal the extent of my ignorance.

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post #4 of 56 Old 10-14-2014, 04:49 PM
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This is what we have to look forward to with Laser projectors in homes.

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post #5 of 56 Old 10-14-2014, 04:53 PM
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^popcorn?

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post #6 of 56 Old 10-14-2014, 04:55 PM - Thread Starter
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Quote:
Originally Posted by Larry Raulston View Post
Very good article and even though I am an ophthalmologist and have studied the retina and intracies of color vision perception I still can't understand how lasers can have much of a future in video projection since they emit a narrow spectrum usually a single wavelength of light. Yet at the same time there are millions of different colors of different wavelengths or hues. How can lasers reproduce each of these individual colors? I still don't understand how that is possible even though I have used a lot of lasers in my career in treatment of retinal diseases and after cataracts, etc.
I hope my asking this question doesn't reveal the extent of my ignorance.
Glad you asked! Even with single-wavelength lasers, if you have a red, green, and blue laser, they can be combined to produce any color within the triangle those primary wavelengths form on the CIE diagram. That's the beauty of trichromatic colorimetry. Not all colors or hues exhibit a single wavelength, especially as they become less saturated; in those cases, the color consists of multiple wavelengths combined together. For example, light (desaturated) green has some red and blue in it.

As I said in the article, one problem with narrowband lasers (as opposed to the wideband primaries you get from a lamp) is observer metameric failure, in which two people see different colors from a given combination of narrowband red, green, and blue. You probably know more about this than most AVS members with your knowledge of how color receptors (i.e., cones) work.

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post #7 of 56 Old 10-14-2014, 04:58 PM
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Quote:
Originally Posted by Scott Wilkinson View Post


Of course, the content must be mastered with high dynamic range, and displaying such content on a laser-illuminated projector typically results in lower optical efficiency and more speckle.

Laser Challenges

Finally, lasers can provide a range color gamuts, though this capability is not without some problems. For one thing, lasers emit light in a very narrow range of wavelengths—essentially a single wavelength. This is great for the BT.2020 color gamut, whose primaries are single-wavelength, but this also results in speckling, an artifact that imparts a grainy look to the image—and not in a good, "film grain-like" way.
Does that mean HDR mastered films with 20.20 color might look better on conventional projectors? Or could they even handle it? Based on the CEDIA wrap up episode I gather that HDR graded film content is a ways away anyhow right?

Two other questions... so basically laser is brighter... that means for 3D they might provide a superior image? Are you aware of any theater chains that might reliably install laser projectors in their premium theaters?

I saw GOTG in IMAX 3D... that looked pretty good to me in comparison to "the box trolls" 3D in a standard theater which looked waaaaay darker.
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post #8 of 56 Old 10-14-2014, 05:05 PM - Thread Starter
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Originally Posted by kevon27 View Post
This is what we have to look forward to with Laser projectors in homes.

One of my all-time favorite movies!
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Scott, I cannot wait for the day when no more bulb lights. ././. Then we'll finally be in heavens on earth.

______

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post #10 of 56 Old 10-14-2014, 06:03 PM
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Thanks for the report Scott. Several comments and questions.

First the diagram of the BPP. Two blue lasers are not required for this system and other versions other than the one illustrated only use one blue laser. This is done by cutting a slot in the laser wheel whereby some of the blue beam passes through the wheel and the other part is used to excite the phosphor. Yellow phosphor is normally used in both one or two blue laser wheel systems because only R and G are derived from the yellow phosphor light and yellow of course is the secondary of R and G. Efficiency meaning more light through and less filtering is needed is a result of starting with yellow light. It is interesting that at Cedia Sony reported that with its single blue laser system it is using a white phosphor wheel. I doubt this is correct since it would be counter productive and counter intuitive to use a white phosphor. It would be so nice if you with your sony contacts could get a definitive answer as to what color phosphor wheel Sony is using and if white, why? Maybe with available phosphors more light can be generated using a white phosphor with more resulting R and G light even after the higher level of filtering required.

Regarding the illustrations of the BPP and three laser system, why is the prism needed after the beam integrator? What function does it do?

Regarding the primary selection vs gamut chart, it should be noted that this is only with respect to laser generated primaries. Wider primaries generated by bulbs and phosphor wheels by filtering do not exhibit speckle or greater speckle.

Regarding bulbs, the lesser area of brightness (with the brightness being highest at the arc) is in fact the area within the bulb or perhaps rather the immediate volume rather than area surrounding the arc, I don't know.

Regarding entendue, because the light emitted by a laser has a low entendue, lenses with a low entendue (which I think mean of a lesser diameter) can be used substantially reducing the cost of the lens.

Regarding speckle I suggest readers look at Wikipedia for good illustrations and explanations.

It is caused by the nature of collated light and surface texture of the object the light is hitting. Blue speckle is hardly visible for a variety of reasons.

R and G speckle can essentially be eliminated by slightly vibrating the screen surface.

Your corrections and comments would be appreciated.

Sorry, can't resist, given your I am sure inadvertent omission to respond, what did you think about the results of the Cedia excitement poll?

And please all readers, this is all in good fun, and no disrespect by me and I am sure Scott, is intended by any of this. I remain truly humbled by all the great work you do here as part of your job and as an AV Geek.

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post #11 of 56 Old 10-14-2014, 06:27 PM
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Perfect! It mean that we'll have a better visual effect.
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post #12 of 56 Old 10-14-2014, 06:42 PM
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Fantastic article! As said thanks for the timely article and Im so looking forward to this technology becoming the norm;both in commercial cinemas and at home.

JBL Pro Cinema/JTR/JVC/Denon/Oppo/Roku Ultra/Elite Screens/Furman/Seatcraft/Acoustimac/AudioQuest
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Great article. What I'd like to know is what the accuracy of our i1D3 and i1 Pro meters will be reading laser light out of the projector. And also if these light sources are read off the SCREEN whether it makes any difference if its laser light, or once reflected if "light is light" and the type no longer matters once reflected. I asked in the CalMAN forums and the response was that we have to wait and see.
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post #14 of 56 Old 10-14-2014, 09:12 PM - Thread Starter
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Quote:
Originally Posted by lovingdvd View Post
Great article. What I'd like to know is what the accuracy of our i1D3 and i1 Pro meters will be reading laser light out of the projector. And also if these light sources are read off the SCREEN whether it makes any difference if its laser light, or once reflected if "light is light" and the type no longer matters once reflected. I asked in the CalMAN forums and the response was that we have to wait and see.
Great question! I suspect that tristimulus meters might have a problem, especially if the laser wavelengths are sufficiently different from the wavelengths the meter is expecting, though conversion profiles might be able to compensate. I would think that a true colorimeter/spectroradiometer would be okay, but I don't know for sure. I agree that, ultimately, we'll have to wait and see.
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post #15 of 56 Old 10-14-2014, 10:38 PM
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Quote:
Originally Posted by Scott Wilkinson View Post

As I said in the article, one problem with narrowband lasers (as opposed to the wideband primaries you get from a lamp) is observer metameric failure, in which two people see different colors from a given combination of narrowband red, green, and blue. You probably know more about this than most AVS members with your knowledge of how color receptors (i.e., cones) work.
We're already starting to see observer metameric failure with technology on the market that's becoming available to consumers. I've run into this with my quantum dot backlit LCD, and it is a known condition with some OLED broadcast monitors.


Quote:
Originally Posted by Scott Wilkinson View Post
Great question! I suspect that tristimulus meters might have a problem, especially if the laser wavelengths are sufficiently different from the wavelengths the meter is expecting, though conversion profiles might be able to compensate. I would think that a true colorimeter/spectroradiometer would be okay, but I don't know for sure. I agree that, ultimately, we'll have to wait and see.
See my long thread about quantum dots in the display calibration forum.

The problem with narrow band emitters is twofold - the first issue is metameric failure, the second is that the narrow band emitters tend to exacerbate any errors in the xyz filters in a colorimeter. These can be compensated for with use of a spectroradiometer to calibrate the meter.

A spectroradiometer though, needs to have enough spectral resolution to work well with a narrow band emitter. The I1-Pro isn't really well suited to the task either though. It has a basic ~10nm resolution and it will miss the peaks of narrow band sources, such as lasers or quantum dots and some of the other emerging technology.

To really do well with lasers would require a higher resolution spectroradiometer, which is a substantial investment. It would really need to have 5nm or better of spectral resolution to do the job with laser sources.

nuke

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post #16 of 56 Old 10-15-2014, 12:52 AM
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Scott, another immensely informative post, right on the heels of your frame-rate post!! Thanks so much for putting this together.

Observer Metameric Failure ("OMF") is likely to be a significant issue for RGB laser sources until the manufacturers can develop spectrally broadened lasers that emit light over a 20-40nm band. I believe this is what Joe Kane was introducing to many of us in his last interview with you.

Green cones exist as a mix of three subpopulations that results in a trimodal distribution with three sensitivity peaks around 528nm, 534nm and 539nm. In order to ensure adequate stimulation of all three subsets, the green bandwidth would need to span from 528-539nm +/- 5nm to account for variability within each subpopulation for a best case scenario of 523-544nm for a spread of 21nm.

Similarly, red cones also exhibit a trimodal distribution with peaks at 555nm, 563nm and 569nm for a span of 14nm +/- 5nm, which results in a final spectrum width of 24nm covering 551-573nm.

I'm not sure about the blue cones, as my primary reference is from 1979 and the authors had a much smaller sample of blue cones. It seems reasonable to expect a similar distribution pattern.

I suspect (hope) the discrete, multiband RGB laser sources will center their output at these sensitivity peaks, rather than just randomly selecting wavelengths based on what's available. On the other hand, multiband should be better than single narrowband, unless the selected wavelengths fall closer to the nulls rather than the sensitivity peaks. Although the graphic describing the wideband sources showed a bandwidth as narrow as 10nm, they will probably still have significant issues with OMF until the bandwidths exceed 20-25nm.

I have not looked at the bandwidth spread of typical phosphors, so I'm not sure to what extent the Pumped Phosphor laser light engines will suffer from OMF.

I hope Dr. Raulston will step in and correct the data in my post based on more recent human research.

Exciting times, indeed!!

Mike

Reference: Visual Pigments of Rods and Cones in a Human Retina, JK Bowmaker and HJA Dartnall, 1979
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Scott What is your opinion in this



Osram Creates a Milestone with Laser Diodes for Projectors

For the first time there is a compact laser multi-chip package. Osram Opto Semiconductors can pack up to 20 blue laser chips in the new PLPM4 450 module


professional laser projectors can achieve a brightness level of more than 2000 lumen with only one component




Lower system costs for laser projectors

Volume production of the PLPM4 450 will start at the end of 2014

http://www.ledinside.com/products/20...for_projectors
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Another advantage of a laser light source is the ability to achieve maximum brightness nearly instantaneously, where a lamp takes time to ramp up. This means that a bright white or colored object can move rapidly across a dark background while maintaining the proper level of brightness, where the same image projected, using a lamp, would appear dimmer even when the peak brightness is well within the capabilities of a lamp.

With regards to the spectral bandwidth of each primary, is it a foregone conclusion that you must sacrifice purity (leading to a narrower color gamut) in order to reduce OMF? For example, there are supposedly some experimental laser projectors that have been made which can reproduce 98% of the BT. 2020 color gamut using single wave length primaries. By going with the multi-band or spectrally broadened lasers can we still potentially hit 100% of rec 2020 or are we going to have to settle for a slightly smaller color gamut?
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post #19 of 56 Old 10-15-2014, 06:02 AM
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Scott:

Thank you, great article. I have a few questions regarding Blue Laser Pumped Phosphorus.

1)I believe current lumen output is 12,000 not the 5,000 quoted for BLPP. The DPI Insight 4K is spec'd at this number
2)Isn't Speckle issue limited to the RGB Laser technology and not the Blue Laser Pumped Phosphorus?
3)Is the observer metameric failure limited to RGB laser technology vs Blue Laser Pumped Phosphurus?
4)I am assuming Rec2020 can be achieved easily by both laser technologies?

Thank you again

Lon
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post #20 of 56 Old 10-15-2014, 09:46 AM
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Rquote=nuke;28230986]We're already starting to see observer metameric failure with technology on the market that's becoming available to consumers. I've run into this with my quantum dot backlit LCD, and it is a known condition with some OLED broadcast monitors.




See my long thread about quantum dots in the display calibration forum.

The problem with narrow band emitters is twofold - the first issue is metameric failure, the second is that the narrow band emitters tend to exacerbate any errors in the xyz filters in a colorimeter. These can be compensated for with use of a spectroradiometer to calibrate the meter.

A spectroradiometer though, needs to have enough spectral resolution to work well with a narrow band emitter. The I1-Pro isn't really well suited to the task either though. It has a basic ~10nm resolution and it will miss the peaks of narrow band sources, such as lasers or quantum dots and some of the other emerging technology.

To really do well with lasers would require a higher resolution spectroradiometer, which is a substantial investment. It would really need to have 5nm or better of spectral resolution to do the job with laser sources.[/quote]

That is absolutely correct and reflects an answer by an individual who knows what he is talking about with respect to this question. With respect to a BPP engine, the issue is only relevant with respect to the blue laser light, the R and G light being derived by filtering yellow non coherent light from excited phosphor on a spinning wheel. How will the tristimulus meters affect the accuracy of the blue measurements?

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post #21 of 56 Old 10-15-2014, 09:49 AM
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Quote:
Originally Posted by mhutchins View Post
Scott, another immensely informative post, right on the heels of your frame-rate post!! Thanks so much for putting this together.

Observer Metameric Failure ("OMF") is likely to be a significant issue for RGB laser sources until the manufacturers can develop spectrally broadened lasers that emit light over a 20-40nm band. I believe this is what Joe Kane was introducing to many of us in his last interview with you.

Green cones exist as a mix of three subpopulations that results in a trimodal distribution with three sensitivity peaks around 528nm, 534nm and 539nm. In order to ensure adequate stimulation of all three subsets, the green bandwidth would need to span from 528-539nm +/- 5nm to account for variability within each subpopulation for a best case scenario of 523-544nm for a spread of 21nm.

Similarly, red cones also exhibit a trimodal distribution with peaks at 555nm, 563nm and 569nm for a span of 14nm +/- 5nm, which results in a final spectrum width of 24nm covering 551-573nm.

I'm not sure about the blue cones, as my primary reference is from 1979 and the authors had a much smaller sample of blue cones. It seems reasonable to expect a similar distribution pattern.

I suspect (hope) the discrete, multiband RGB laser sources will center their output at these sensitivity peaks, rather than just randomly selecting wavelengths based on what's available. On the other hand, multiband should be better than single narrowband, unless the selected wavelengths fall closer to the nulls rather than the sensitivity peaks. Although the graphic describing the wideband sources showed a bandwidth as narrow as 10nm, they will probably still have significant issues with OMF until the bandwidths exceed 20-25nm.

I have not looked at the bandwidth spread of typical phosphors, so I'm not sure to what extent the Pumped Phosphor laser light engines will suffer from OMF.

I hope Dr. Raulston will step in and correct the data in my post based on more recent human research.

Exciting times, indeed!!

Mike

Reference: Visual Pigments of Rods and Cones in a Human Retina, JK Bowmaker and HJA Dartnall, 1979
These times are not now.
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Scott. This is off topic but since ou are monitoring this thread, I have a suggestion for another home page poll and/or thread.

I just received my issue of WSR for Oct 2014. In it on page 63 is a full page ad by DTS that says only the following "Sound changes the way we see. All you have to do is listen." That's the ad. It would be interesting to get the AV Science Forum members take on these two statements.

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post #23 of 56 Old 10-15-2014, 10:32 AM
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Originally Posted by LJG View Post
Scott:

Thank you, great article. I have a few questions regarding Blue Laser Pumped Phosphorus.

1)I believe current lumen output is 12,000 not the 5,000 quoted for BLPP. The DPI Insight 4K is spec'd at this number
2)Isn't Speckle issue limited to the RGB Laser technology and not the Blue Laser Pumped Phosphorus?
3)Is the observer metameric failure limited to RGB laser technology vs Blue Laser Pumped Phosphurus?
4)I am assuming Rec2020 can be achieved easily by both laser technologies?

Thank you again

Lon
Hi Lon. In BPP or BLPP the only laser light hitting the screen is from the blue laser. While speckle would be generated by any color laser light, because we are talking about blue laser light it and its contribution to other colors is essentially not noticeable by the viewer.

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post #24 of 56 Old 10-15-2014, 11:11 AM - Thread Starter
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Originally Posted by mreendoor View Post
Scott What is your opinion in this

Osram Creates a Milestone with Laser Diodes for Projectors

For the first time there is a compact laser multi-chip package. Osram Opto Semiconductors can pack up to 20 blue laser chips in the new PLPM4 450 module

professional laser projectors can achieve a brightness level of more than 2000 lumen with only one component




Lower system costs for laser projectors

Volume production of the PLPM4 450 will start at the end of 2014

http://www.ledinside.com/products/20...for_projectors
This is one type of laser-diode component used in laser projectors known as a multiple emitter, and it seems quite promising.
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post #25 of 56 Old 10-15-2014, 11:15 AM - Thread Starter
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Originally Posted by HockeyoAJB View Post
Another advantage of a laser light source is the ability to achieve maximum brightness nearly instantaneously, where a lamp takes time to ramp up. This means that a bright white or colored object can move rapidly across a dark background while maintaining the proper level of brightness, where the same image projected, using a lamp, would appear dimmer even when the peak brightness is well within the capabilities of a lamp.

With regards to the spectral bandwidth of each primary, is it a foregone conclusion that you must sacrifice purity (leading to a narrower color gamut) in order to reduce OMF? For example, there are supposedly some experimental laser projectors that have been made which can reproduce 98% of the BT. 2020 color gamut using single wave length primaries. By going with the multi-band or spectrally broadened lasers can we still potentially hit 100% of rec 2020 or are we going to have to settle for a slightly smaller color gamut?
By definition, BT.2020 uses single-wavelength primaries, so I'm not sure how it could be achieved with multiband or spectrally broadened lasers. This is one reason some industry experts, including Joe Kane, advocate for the P3 gamut over BT.2020 when it comes to UHD. I hope to have Bill Beck as a guest on Home Theater Geeks, and if I do, I'll be sure to ask this question.
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post #26 of 56 Old 10-15-2014, 11:24 AM - Thread Starter
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Originally Posted by LJG View Post
Scott:

Thank you, great article. I have a few questions regarding Blue Laser Pumped Phosphorus.

1)I believe current lumen output is 12,000 not the 5,000 quoted for BLPP. The DPI Insight 4K is spec'd at this number
2)Isn't Speckle issue limited to the RGB Laser technology and not the Blue Laser Pumped Phosphorus?
3)Is the observer metameric failure limited to RGB laser technology vs Blue Laser Pumped Phosphurus?
4)I am assuming Rec2020 can be achieved easily by both laser technologies?

Thank you again

Lon
1. You're right, the DPI Insight 4K laser is spec'd at 12,000 lumens. I got the 6000-lumen figure from Bill Beck's presentation, and I forgot about the DPI.
2. I believe that speckle is limited to RGB projectors and not a problem with BPP models, because the red and green primaries in BPP projectors are wideband and incoherent. The blue primary comes directly from a laser, so it's narrowband and coherent, but blue laser light suffers the least from speckle.
3. I believe you are correct here as well, for the same reasons as in point 2.
4. I don't think that BT.2020 can be achieved using BPP technology, because the red and green primaries are wideband. Even the DPI Insight 4K Laser shown at CEDIA "barely exceeds BT.709" according to the DPI reps I spoke with.
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post #27 of 56 Old 10-15-2014, 11:34 AM - Thread Starter
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Does that mean HDR mastered films with 20.20 color might look better on conventional projectors? Or could they even handle it? Based on the CEDIA wrap up episode I gather that HDR graded film content is a ways away anyhow right?

Two other questions... so basically laser is brighter... that means for 3D they might provide a superior image? Are you aware of any theater chains that might reliably install laser projectors in their premium theaters?

I saw GOTG in IMAX 3D... that looked pretty good to me in comparison to "the box trolls" 3D in a standard theater which looked waaaaay darker.
I don't think that conventional (lamp-based) projectors can reproduce BT.2020, and I have serious doubts that they can reproduce HDR content as well. Christie is experimenting with a dual light engine for HDR projection, but I need to research that more before I understand it. And you're right, HDR-graded content is not imminent; this is another chicken-and-egg problem—the studios don't want to grade content for HDR until there is an installed base of HDR displays, and display makers don't want to bring them to market until there is content to show on them. It will be interesting to see how this plays out.

I believe that lasers can produce a superior 3D image, in large part because they are brighter. I've heard that Imax is about to or in the process of installing dual laser projectors in some of its theaters; I don't know of any others.

I'm not surprised that Imax 3D looked better than 3D in a standard theater; Imax uses dual projectors for 3D, so it's twice as bright as a single-projector presentation.
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post #28 of 56 Old 10-15-2014, 01:14 PM
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Originally Posted by Scott Wilkinson View Post
...And you're right, HDR-graded content is not imminent; this is another chicken-and-egg problem—the studios don't want to grade content for HDR until there is an installed base of HDR displays, and display makers don't want to bring them to market until there is content to show on them. It will be interesting to see how this plays out.
Some of the pieces of the puzzle have already started to come together. We have video cameras that can capture HDR. We have color grading software that can handle the higher bit depth required. We have a proposed method of transferring HDR information from source to display that is supposedly backwards compatible (e.g. Dolby Vision), but no consumer displays that actually take advantage of it, yet. We have both laser projectors and flat panel displays with light output capabilities that could qualify as HDR-capable, including some that utilize their own proprietary dynamic range expansion algorithms (e.g. Sony's X-tended Dynamic Range Pro). And, we have rumors of full 10 bit support for the upcoming UHD/4K Blu-Ray standard as well as the rough UHD-1 Phase 2 spec. I suspect that the next steps are...

1) Broader adoption of laser projection in commercial cinemas. Once that hits critical mass...
2) A director such as James Cameron or Peter Jackson will decide to make their next box office hit utilizing HDR (like they have done/are doing for 3D and HFR)
3) This will start the HDR movement for the studios with regards to commercial cinema releases and push the remaining theaters to upgrade their projectors.
4) With cinematic HDR content already in existence, the studios and consumer electronic industry will see this as the next feature to use as a selling point to get consumers to upgrade their home theater equipment and movie collection again. I think this is already in their plans.
5) Displays, playback devices, and receivers that support actual HDR content will become available with a handful of titles being released to the home in HDR at the same time.
6) Assuming sales of HDR capable equipment are sufficient, more and more HDR content will be released.

My guess is that we'll get WCG and HDR as a combined package, since there is so much overlap in the technology required to make them a reality. I think that #2 is the key to the whole thing. Once that happens, the rest will occur over the course of 2 years.
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Originally Posted by Scott Wilkinson View Post
1. You're right, the DPI Insight 4K laser is spec'd at 12,000 lumens. I got the 6000-lumen figure from Bill Beck's presentation, and I forgot about the DPI.
2. I believe that speckle is limited to RGB projectors and not a problem with BPP models, because the red and green primaries in BPP projectors are wideband and incoherent. The blue primary comes directly from a laser, so it's narrowband and coherent, but blue laser light suffers the least from speckle.
3. I believe you are correct here as well, for the same reasons as in point 2.
4. I don't think that BT.2020 can be achieved using BPP technology, because the red and green primaries are wideband. Even the DPI Insight 4K Laser shown at CEDIA "barely exceeds BT.709" according to the DPI reps I spoke with.
A minor technical point of no real consequence, from reports I have read I think DPI said that the projector came very close to achieving 2020 and only missed because the blue laser was not quite saturated enough though very close to what was needed.
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post #30 of 56 Old 10-15-2014, 02:53 PM
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Originally Posted by Scott Wilkinson View Post
I don't think that conventional (lamp-based) projectors can reproduce BT.2020, and I have serious doubts that they can reproduce HDR content as well. Christie is experimenting with a dual light engine for HDR projection, but I need to research that more before I understand it. And you're right, HDR-graded content is not imminent; this is another chicken-and-egg problem—the studios don't want to grade content for HDR until there is an installed base of HDR displays, and display makers don't want to bring them to market until there is content to show on them. It will be interesting to see how this plays out.

I believe that lasers can produce a superior 3D image, in large part because they are brighter. I've heard that Imax is about to or in the process of installing dual laser projectors in some of its theaters; I don't know of any others.

I'm not surprised that Imax 3D looked better than 3D in a standard theater; Imax uses dual projectors for 3D, so it's twice as bright as a single-projector presentation.
TY for the info, well now I know to see 3D films in IMAX from now on if I can

One quick unrelated question (my apologies if this is a derail)... in one of the home theater geeks episodes I recall someone brought up 8k infrastructure being installed (in Japan I think? I think you questioned why and in response whoever was talking about it had assumed it might be to save on upgrade costs in the long term). Do you remember which episode that might have been?
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