The Dmd Device; The Grayscale Image; Adding Color - Barco F90 Service Manual

4. DLP System General Description
4.2

The DMD Device

DMD Device
Image 4-2
At the heart of every DLP™ projection system is an optical semiconductor known as the Digital Micromirror Device, or DMD chip,
which was invented by Dr. Larry Hornbeck of Texas Instruments in 1987.
The DMD chip is probably the world's most sophisticated light switch. It contains a rectangular array of hinge-mounted microscopic
mirrors, each measuring less than one-fifth the width of a human hair, and corresponding to one pixel in a projected image.
When a DMD chip is coordinated with a digital video or graphic signal, a light source, and a projection lens, its mirrors can reflect an
all-digital image onto a screen or other surface. The DMD and the sophisticated electronics that surround it are what we call Digital
Light Processing™ technology.
The F90 DMD chip is part of the Texas Instrument DLP9000 family and features over 4 million micromirrors on each chip, offering a
dazzling high resolution 2560 x 1600 (WQXGA) array.
4.3

The Grayscale image

Grayscale
Image 4-3
A DMD panel's micro-mirrors are mounted on tiny hinges that enable them to tilt either toward the light source in a DLP™ projection
system (ON) or away from it (OFF)-creating a light or dark pixel on the projection surface.
The bit-streamed image code entering the semiconductor directs each mirror to switch on and off up to several thousand times
per second. When a mirror is switched on more frequently than off, it reflects a light grey pixel; a mirror that's switched off more
frequently reflects a darker grey pixel.
In this way, the mirrors in a DLP™ projection system can reflect pixels in up to 1,024 shades of grey to convert the video or graphic
signal entering the DMD into a highly detailed grayscale image.
4.4

Adding Color

Adding color
Image 4-5
The on and off states of each micro mirror on the DMD chip are coordinated with the three basic building blocks of color – Red,
Green & Blue (RGB). For example, a mirror responsible for projecting a purple pixel will only reflect red and blue light to the projection
surface. The switching of the mirrors and the proportion of time they are 'on' or 'off' is coordinated according to the color shining on
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723–0016 F90 01/12/2017