Originally Posted by Alan Gouger
I have found 1 chip DLP to show more banding due to its color bit depth. Add to this the color wheel is filtering high end information. 1 chip can look sharper but that is edge sharpness. Comparing to a well converged 3 chip DLP the 3 chip will always display more detail.
This may have been true before the pulsed lamp and brilliant color technology using the Osram or Vidi lamps were introduced and before a workable DI was introduced but since they have been introduced ,this is not true now because another 2 bits to 4 bits of depth has been added. Before these innovations the single chips had barely enough time to achieve 256 levels of grey. The least significant bit is close to at 22 usec the switching speed of dlps 15 usec and tricks like dithering the signal both spatially and temporarily were used to overcome this and in some cases caused artifacts
with the OSram pulsed lamp and brilliant color technology developed jointly by Osram and TI these artifacts are gone.
No doubt the 3 chip dlp can display a larger bit depth because it has 3 times the amount of time over a single chip to do so but that's a mute point because the highest RGB bit depth is only 8 bits
The qualifier "well converged" is the key to the problem. on a 3 chip to hold a half chip decenter you have to position and hold that the blue and red chip to the green chip to get half a pixel convergence to 5 microns and you still have tip tilt and rotation tolerances to consider.
during Cedia I compared the Sim2 Ht3000E which was the first projector to use the Osram lamp technology developed by Texas Instruments against their 3 chip 1080p. I went back 4 times and compared those two projectors and the Sim2 ht3000 was sharper , had richer colors and had better blacks.
The three chip was brighter. However I asked people around me whcih projector they preferred and to a man they all liked the image of the 3000e to the 3CX 1080p
It was noted in the Lumis Cheerleader forum after the ravings subsided that the projector they were raving about had a misconvergence of .75 pixels. that may not seem like much but it is enough to degrade the resolution in many scenes to that of a 720P projector.
Misconvergence is much worse than lateral color because it degrades the image at the center of the eye's vision where the eye has 6 times the resolution it does at its periphery.
there is no doubt in my mind that if you happen to be one of the lucky ones who happen to get a perfectly converged 3 chip Lumis from Sim2 with the dark chip 4 that you will be very happy with that projector but you also have a very good chance of getting one that is out of convergence "Quecumber" and when that happens you have paid an awful lot for a very bright low resolution projector and since their is no specification on convergence and Sim2 in the past has been extremely reluctant to replace projectors that work but under perform than you the owner will have a problem. They will just tell you it is in spec ,which of course, is true because there is no specification on convergence.
You make a single chip dlp projector with a dark chip 4, a good projector lens Ti's brilliant color with a good DI and an Osram lamp and except for power out no 3 chip projector will in production consistently be capable of competing with it.
Once they start making RGB leds with enough power the days of 3 chip projectors for use inside the home will be over as long as the bit depth on blue ray discs is only 8 bits.