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60 4. Building a Practical VR System
DLP projectors have high refresh rates and deliver a high resolution. At
the core of DLP projectors is the Texas Instruments MEMS (microelectrome-
chanical system) chip and the digital micromirror device (DMD). Figures 4.8
and 4.9 illustrate the DMD and how DLP projectors work. The word mir-
ror in DMD gives a vital clue to the idea behind the DLP. The DMD chip
is an array of microscopic mirrors, one mirror for each pixel in the image.
The microscopic mirrors are attached to the chip’s substrate by a small hinge,
and so it can be twisted into two positions. In one of these positions, it is
angled in such