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Discussion Starter · #1 ·
I know this topic may have been discussed many times, but Peters answer from TI was very vague. When or will DLP eliminate rainbows or is it only going to be through 3 chip DLP and cost prohibited?


I think TI will be left behind if they do not improve on this area, they would have to produce a DLP 3 chip for under $10,000.00.Which seems unlikely soon. This is a serious flaw on TI. Current LCOS, D-ILA ,LCD formats are getting better, without rainbows. If Sony SXRD is what it is claimed to be DLP will loose ground, Sony will have better CR, smaller pixels, higher resolution and no rainbows.


Is the DLP rainbow an issue for a great number of people or is this over rated?


Please give me your opinions.


Thanks

Ross
 

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Not a great number of people, but if you are one of them, it certainly isn't overrated.


I don't think the number of people is high enough that TI will be left behind though. Since this forum is replete with picky *******s, myself included, and there is a high percentage of DLP owners, if not a majority, it seems highly unlike the the general populace would be more averse.


IMO


BB
 

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Another data point that TI won't ignore: (from their 1st Q financial report , I added the emphasis)
Quote:
TI's remaining Semiconductor revenue increased 8 percent sequentially due to DLP product revenue growth in excess of 25 percent, as well as growth in microcontrollers, royalties, RISC microprocessors and ASIC. Compared with the year-ago quarter, this revenue increased 26 percent as DLP product revenue more than doubled, and revenue from RISC microprocessors, royalties and standard logic products expanded at rates over 20 percent.
TI seems to be getting rewarded (with $$$) for their current strategy. I wouldn't blame them for sticking with it.
 

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I think it is more a matter of the drawbacks people are willing to live with.


I get near sick watching cheap DLP projectors and I refuse to have a guest in my house experience the same thing. Everyone I've ever shown DLP has seen them at some level from mild (wouldn't bother them at all, the beautiful picture makes them irrelevant) to severe (non-watchable). I've noticed people won't comment on them until asked and usuall responce is that there seemed to be some color flicker - as tho the source was flawed.


Personally, I think there's a healthy, competitive future for DLP and LCD techonologies. I am surprised that is hasn't been more of an issue to bring down the cost of 3 chip DLP rather than put tons of R&D into new things like SXRD - but all that can happen in the end is a better PJ for everyone.


-Mike
 

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Ross, it would have been nice if you noted which DLP products you were seeing rainbows on. Are you seeing rainbows on the latest HD2 DLP projectors in the $10K and up category (i.e. those with the fastest color wheels)?
 

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Discussion Starter · #6 ·
Wanman,


I see them on all projectors, front and rear HD1, HD2 with 5x color wheel.


I believe the reason TI has made so much money is Samsung rear projector, great price point, they have sold tons.


Thanks for your response keep them coming.


Ross
 

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DLP will always produce rainbows - however, the number of people that are truly affected by them has been getting smaller and smaller due to the increase in color wheel speed and better processing.


3-Chip DLP is the only true answer to getting rid of rainbows for a DMD device.


I doubt TI will be left behind - by the time SXRD catches up, TI will have a very firm customer base to draw upon, and most likely, will have captured the market for this type of technology (especially in the FP world). You have to admit that it has a lot of "bang for the buck", regardless of its shortcomings.


I believe the rainbow issue is vastly overrated - not to say that there aren't those who have a real issue with them. Don't forget that this crowd at AVS is very discerning when it comes to picture quality. The smallest little glitch (or rainbow) on one person's projector can cause a mild riot in these parts.


I believe everyone can see them (rainbows), if you look for them. I can force myself to see them if I want to, but all I see during movie time is a bright, clear, and beautiful 96" wide picture :). BTW, no headaches or dizziness either.
 

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What rainbows?
 

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Rainbows on the 2x color wheel projectors are easily seen for probably 20% of the population, but that's from an unreferenced Projector Central estimation. In my experience, 2 out of 5 people I have shown my projector to see them. 2 of those who didn't see them get eyestrain, one of whom gets it severely to the point of watery eyes on a 4x wheel projector.


I suspect that eyestrain goes away after several (probably 10 or more) hours of viewing.


Unfortunately for me, I see rainbows on all single chip DLP projectors, and I get eyestrain 50% of the time. I haven't yet figured out why I get eyestrain some times, and not others, although I suspect being slightly tired (blood sugar levels low?) contributes to it.


I also recall getting headaches at the Calgary Film Festival in one of the theaters there...they were using a digital projector of some sort. It may have been a 3 chip DLP or just plain old neck strain. Too many damn variables. :)


Concerning guests, rainbows aren't my main concern (with a 4x wheel or faster, very few people see them)...but the issues of eyestrain and headaches worries me. I don't want my guests to feel sick!


As for rainbows, in my mind they seem like motion artifacts for me. When movement occurs, my brain sees the images as smeared, like watching a CRT with extremely long phosphor times. Ghosting, except with red, green, and blue halos around everything that moves, or when I move my eyes to focus on a different subject in the frame.


Remember those old LCDs with horrid refresh rates? That's what it looks like to me. However, I'm slowly adapting to it. It's like getting used to image tearing or fixed pattern noise or CRT convergence problems but worse. :)


Huey had some good suggestions minimizing rainbows. I think the "Month with the HT1000" thread includes his tips.


1) Don't move your eyes. Dammit this is hard for me...I love looking at the details in the image, to see how skillfully the director composed the shot. With rainbows, I'll have to give up this aspect of movie-watching that I love.


2) Sit further back. 2x or more screen width viewing distance helps.


3) Dim the image...using either a gray screen, neutral density filter, or projector settings, or all of the above.


4) Brute-force your brain into adapting. Watch lots and lots of movies on the projector. Hopefully, after a few hundred hours, you won't see them anymore (less if you're not overly sensitive like me).


5) Use a high-quality source. An HTPC or expensive deinterlacer/scaler is best. Progressive scan DVD is 2nd best. Cable feed / composite video / svideo can make rainbows worse.


I'm sure there are other suggestions for coping. I hope this post was constructive for those of you out there who see rainbows, and a change of pace from the "plausible deniability" often expressed in threads like these. :)
 

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Somewhere over the rainbow

3 chip DLPs lie
 

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Rainbow demon....


Nich
 

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Rainbows come from the color wheel and not the chip so until they somehow figure out how to make a color wheel that wont produce them, you are out of luck


I originally purchased the Dwin TV1 and I saw rainbows everywhere and drove me crazy. I seem to be very sensitive to them. When I went to CES, I saw rainbows on all of the HD-2 projectors. However, the new color wheels have seemed to reduce the number of rainbows, so while I still saw them, they were limited in numbers and I could probably live with them
 

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Ironically, the increase in contrast and brightness of the new HD2 DLP units seems to negate the increased colour wheel, which hasn't changed from HD1 (Sharp Z9000, for example) designs.


I predict a strange thing...as the brightness and contrast of DLPs increases, using the same speed of colour wheel, which won't get much faster, the incidents of rainbows will also increase.
 

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Actually, it has been said more than once on this forum that rainbows are theoretically possible even with 3-chip projectors. There was even a link to a published academic paper on the subject. The problem with DLPs is not just the color wheel, it is also the PWM method by which they represent color intensities/gray scales.


Think about it... at any given instant, a 1-chip DLP can show only two colors: the color selected by the wheel, and blank. Furthermore, there are no gradations of color, just full on or full off.


Well, with a 3-chip, there are no gradations either! So 3-chip DLP can show only 8 colors at any given instant.


Of course, they are much less likely---in the same sense that they are less likely with a 5x color wheel than with a 2x---but they are still possible.
 

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Quote:
Originally posted by Daniel Hutnicki
I could probably live with them


I could probably live with SARS too if it were just a bit more mild.
 

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I do not see what all the fuss is about. If you see rainbows than don't go the DLP route. There are competing technologies that will make you satisfied on that front. TI will not miss your business.
 

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Are you saying that SARS and rainbows are in the same catagory. I dont mean one is a sickness and the other is eye irration, but are you saying that they are extreme forms of a problem
 

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Wow!


Imagine you are an innocent bystander accidentally stumbling onto this thread.

Imagine reading all the responses with all their severity of emotions...


Would you not think that TI is heading for bankruptsy by producing and selling such a crappy product that severely affects people just like SARS?


It seems to me that quite the opposite is happening with TI's DLP products gaining market share in all types of projectors/RPTV's...

As for the 3 chip "rainbow" possibility... well, if you can see a micromirror flickering with its 5microsecond period, I suggest you contact the Guinness book of records for the "fastest eye in the world" title. It's waiting for you...


just my 2 cents...
 

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Laugh if you want, Andrikos, but it's not as simplistic as you seem to think it is. Rainbows depend not just on the mirror switching rate but on the motion in the image being displayed as well. I might add that someone on this forum has seen DLP effects first-hand on a 3-chipper, if I remember correctly. So it doesn't take Guinness book eyes to see it.


I agree, though, the rainbow problem is not going to make a huge dent in DLP sales, as long as companies are willing to accept returns when people discover that they get headaches while using the projector they just bought.
 

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Imagine you are an innocent bystander who stumbles onto a "Rainbows are a non-issue" thread, and find out later that you are prone to rainbows or DLP eyestrain.


Too bad I looked at the wrong threads...I should have "seen" it coming. :D


BTW, I can see the micro-mirror flickers. Don't they switch at a maximum of 20 usec? I'm pretty sure I won't see them flicker at 20 usec, but for mid-range colors (like half grey), it's pretty obvious only if you stand right up to the wall.


Seeing flicker isn't the main issue though...it's the eyestrain/headaches that should be the main concern.


There really should be a sticky thread outlining the pros and cons of single-chip DLP. That will cut down on the emotional threads you see everywhere.
 
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