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Discussion Starter · #1 ·
I've been reading about DLPs since I saw them written up in an early 90s IEEE Spectrum and I've always thought that they were going to (eventually) replace CRTs. Of course, that was a decade ago and a lot has happened in Display Technology. But, one thing that hasn't changed regarding DLPs is the light source.


There seems to be two ways to produce the full-color image: One DLP Micro Mirror device (MMD) and a spinning color wheel, or three MMDs and a color-splitter to provide RGB for each MMD. Has no one thought to use a single DLP MMD with three separate Primary Color light sources that can be switched at a fast enough rate to eliminate the dreaded "Rainbow" effect?


I know that LEDs have made great strides in the amount of light that can be produced. How many LED stoplights have you seen lately? So, I take it that red and green high-output LEDs can be produced at a cost-effective rate. If blue LEDs are two-four times the cost of red or green, wouldn't it still be possible to produce a bright enough to provide an acceptable light level in an RP DLP set? (This is why I'm asking this question here instead of the Projector forum)


Instead of a color wheel, the set would cycle through the LEDs at a rate that would be faster than any color wheel (goodbye rainbows!) Better still, instead of R128, R64, R32, R16, R8, R4, R2, R1, pause, G128, G64. G32, G16, G8, G4, G2, G1, pause, B128, B64, B32, B16, B8, B4, B2, B1, pause, start over; you could eliminate the pauses between color changes and interleave the colors (R128, G128, B128, R64, G64, B64, etc.) And, it would be silent since there would be no moving parts. Lastly, LEDs are good for hundreds of thousands of hours, so it should last as long or longer than the MMD.


Another benefit, instead of a fixed light level, you could extend the effective contrast of such a set by reducing the light intensity for low-light scenes, something that can't be done with current light sources. Instead of gray fog, just cut the light level down and increase the number of bits available to render such a scene.


So, will this ever happen?
 

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Or better have a 3 Color Leds and a 3-Chip System with each Lead Pointing at each Chip. This would eliminate all pauses compleatly and provide much more colors to the TV.
 

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Discussion Starter · #3 ·
I guess I should have read the other thread about 3 DLP sets and posted this over there. Perhaps the Moderator should merge these threads?


VTBoy, my idea would be to produce a higher quality RP set that wouldn't have the extra cost of an additional two MMDs (or DMD as others have called them) I tried to price the Mustang HD2 chip. The best I could find was a developer set which cost close to $5,000. Hopefully TI sells the HD2 DLP to manufacturers at a much reduced cost! But, I have to believe that the primary cost item in any current DLP projector or RPTV is the DLP device itself. Next is probably the light bulb!
 

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Roland, I believe TI refers to the raw part as a digital micromirror device or DMD. Not sure, but I think that is the generic term.


I am not sure what you posit is realistic nor whether it would work but it sure seems like an interesting idea. I'm not sure that color diodes of sufficiently uniformity are cheap or easy to get, but they are getting cheaper and easier to get.


I would post it in the projector forum because there are a lot of savants in there who would make it an interesting thread. Give it a shot as it should provoke a good conversation. Seriously.


Mark
 

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Discussion Starter · #5 ·
Quote:
Originally posted by rogo
I would post it in the projector forum because there are a lot of savants in there who would make it an interesting thread. Give it a shot as it should provoke a good conversation. Seriously.
Mark, I just did that. We'll see what happens there.


Me, I'm not in the market for FP. But, I guess if an LED-based illuminator pushes the price too high, then maybe the $5K+ forum in more appropriate.
 

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It does seem possible that you can't get enough light output from a small enough LED array at this point to achieve what you are positing.


I know the traffic lights seem awfully bright, but they are a grid with a large number of LEDs and I'm not really sure that for a given surfact area they have the light output of a projector bulb.


Mark
 

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Discussion Starter · #7 ·

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Semiconductor lasers would be perfect for this application. They are not expensive. bright, and produce a perfect uniform light.


Kirill
 

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Quote:
Originally posted by Foxbat


Instead of a color wheel, the set would cycle through the LEDs at a rate that would be faster than any color wheel (goodbye rainbows!)
HI All,


First time post so excuse my newness. What is this about rainbows and DLP? Its the first I have heard about it.


Thanks,

Barry
 

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Use the Slowest Search option and search in the projector forums. There are great explanations there.
 

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Discussion Starter · #11 ·
From the other thread in the High-End Projectors thread, Lumileds™ has a white paper on using their Luxeon™ LEDs for digital projectors. They say not yet, maybe 2-4 years or so. However, it may be practical to have a rear projection unit in less time than that.


With that in mind, I'm thinking of changing my RP purchase plans. I'd rather spend $1,500 for a CRT-based RP HD set today, knowing that I'd be replacing it in five years with an LED-based DLP rear-projector capable of 1,920 x 1080, than spend $4,500-$5,000 for the HLN5607, knowing that in five years, I'd still want to buy the higher rez set! Pixel-envy, don't 'cha know...
 
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