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Deciding on a DLP:
Texas Instruments has developed (over the course of many years) a completely
new way of projecting video called the DLP (short for Digital Light
Processor). DLP has created a whole new category of inexpensive projector
systems and has also led to a digital revolution in those old-fashioned movie
theaters you used to go to before you got a home theater. If you were lucky
enough to see Star Wars: Episode III — Revenge of the Sith in a digital theater,
you have already seen DLP (a super-high-end, expensive version) in action.
The DLP is an entirely digital process that utilizes a semiconductor generically
called the DMD (digital micromirror device). The DMD contains over a
million incredibly tiny, hinged mirrors. Each of these mirrors represents a
single pixel on your video image. The DLP chip’s electronic logic controls the
hinges on the mirrors, turning them so that they either reflect light (onto
your screen) or block it (creating a dark spot on the screen). When the DLP’s
“brains” turn these mirrors on and off, the mirrors create different levels of
light between black and white that result in a grayscale version of your image.
A device called a color wheel filters light from a lamp (like the lamps found in
LCD projectors), reflects this off the mirrors on the DLP chip, and provides
the color in your image. This is really a Mach III fly-by of the details of DLP;
if you want to know the nitty gritty, check out Texas Instruments’ site at
www.dlp.com.
The DLP system we just described, with the color wheel, is called a single-chip
DLP solution, and is by far the most common in consumer DLP projectors.
Movie theater projectors (and a few ultra-expensive home theater models)
dispense with the color wheel, and use three DLP chips (one for red, one
for green, and one for blue). These three-chip projectors can produce more
gradations of color than a single-chip system but cost a heck of a lot more.
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