What is the DLP technology?
The DLP microchip is an optical semiconductor. Invented in 1987 by Larry Hornbeck of Texas Instruments, it is also called the digital micromirror (DMD) chip. In terms of its functionality, the DLP chip can be regarded as the most elaborate light switch in the world. This sophisticated technology is at the core of the DLP projector system. The mechanism works through an interlocking system of minute mirrors, each measuring less than one-fifth the thickness of a human hair. The DLP projection system comprises up to 2 million of these micromirrors, which are hinged to allow movement and arranged in a rectangular configuration. The projection system operates by integrating the optical semiconductor into a system comprising a digital video or graphic signal, a light source, and a projection lens. In operation, the micromirrors reflect the image onto a screen or other appropriate surface. This is called DLP technology (Figure 4.29).
188.8.131.52 The Greyscale Image
The micromirrors on a DLP chip 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), thus 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; when a mirror is switched off more frequently it reflects a darker grey pixel (Figure 4.30).
In this way, the mirrors in a DLP projection system can reflect pixels in up to 1024 shades of grey to convert the video or graphic signal entering the DLP chip into a highly-detailed greyscale image.