Just thought I would post a response I had in another thread so any newbie can find it quickly:
EDIT--> There does exist two and three chip DLPS. Two chip still uses a colour wheel for 2 of the 3 colours, and hence must still exhibit some rainbow (or YM flashing http://www.avsforum.com/ubb/smile.gif
) artifacts. 3 chip DLP does not have a colour wheel, so no rainbow, and better colours. However, they are big $$$, for the time being.
(From another thread, regarding a forum member who asked why he sees rainbows with his projector http://www.avsforum.com/ubb/smile.gif
Ok, before you get told to do a search, I will try to help you here:
The DLP you own is a single chip DLP. That means to produce an image, which LCD and DILA do using three panels (of different colour), the DLP must use one chip, and flash the colours on it at separate times, instead of making one image from the combination of three panels. To accomplish this, singlechip DLP uses a colour wheel, which flashes the colours on the chip one after another. The chip is sync'd with the wheel, so the mirrors are in the correct position when they get their dose of colour. Some colour wheels may use a clear section to boast the light output.
This is what the colour wheel does. The rainbow effect you see is what can simply be called an imprint on your eyes of the flashing of the colour wheel. That is, when you move your eyes quickly to a different location, you are getting glimpses of how the image is actually made up: of three separate, sequenced images. You normally won't see it if you don't move your eyes or head.
A new thing that is going on is to speed up the colour wheel, either by making it faster or adding more segments of colour, to the point where it is changing the colours faster than your eye differentiate and imprint.
Think of a strobe light. The faster it strobes, the less you can tell the difference between it being on and off. This is how film works, by flashing images faster than the eye can tell.
Hopefully, this was usefull, from all the knowledge I have aquired at my time here in the forum.
Sharp xv-s55u (Don't laugh) http://www.avsforum.com/ubb/smile.gif
[This message has been edited by David Mendicino (edited 04-28-2001).]