Originally Posted by Chris Burkart
Maybe you meant DLP? As sensitive (picky?) as I am I've never seen anything like rainbows on an LCD of any size.
The pulse-width-modulation effect discussed in the above-referenced paper, which we are assuming is the cause of the rainbow effect on a plasma screen, affects LCDs equally. The paper discusses the effect mainly on LCDs, with a passing mention that it affects plasma screens too. It's far worse on single-chip DLPs because of the sequential color projection.
On an LCD or plasma, what you're seeing from one RGB pixel in a 1/60th second frame interval might be something like:
Mostly 3 colors overlapping, but resulting in a fleeting impression of yellowness for part of the interval, and greenness for another part of the interval. That interval *should* be too short for your eye to perceive separately, unless your eye is sweeping rapidly across the display and pauses there on one of its microjumps for less than 1/60th sec.
On a single-chip DLP, the above pixel will be displayed in sequential colors as:
but a little quicker so that it's still 1/60th sec. Now you have much more opportunity to see the separate red, green and blue phases. But what DLPs actually do now is to have multiple repetitions on a faster-spinning color wheel, so that what you actually get in 1/60 sec is something like:
RRRRR GGGGGGGBB RRRRR GGGGGGGBB RRRRR GGGGGGGBB
That reduces, but not eliminates the opportunity to see single colors (rainbow effect).