Digital Micromirror Devices (DMDs)

(aka Digital Light Processing / DLP / commercial name)

(A Micro-Optical Electromechanical Device - MOEMS - for Display Applications)

Texas Instruments

  • Microelectromechanical (MEMs) devices

  • Fabricated using VLSI processing techniques

  • 2-D array of mirrors

  • Tilts +/- 10 degrees

  • Electrostatically controlled

  • Truly digital pixel

Three Mirrors Project Image

Incoming light hits the three mirror pixels. The two outer mirrors that are turned on reflect the light through the projection lens and onto the screen. These two "on" mirrors produce square, white pixel images. The central mirror is tilted to the "off" position. This mirror reflects light away from the projection lens to a light absorber so no light reaches the screen at that particular pixel, producing a square, dark pixel image. In the same way, the remaining mirror pixels reflect light to the screen or away from it. By using a color filter system and by varying the amount of time each of the DMD™ mirror pixels is on, a full-color, digital picture is projected onto the screen.

  • Suitable only for projection displays

  • Gray levels via Pulse-Width Modulation (PWM)

  • Color via multiple chips or a color-wheel

  • Excellent resolution and fill-factor

  • Light efficient

  • Problems with stray light and flicker

SXGA DMD on Hand
SXGA device with black aperture: 1280x1024; 1,310,720 mirrors

DMD™ and Ant Leg
Micrographic photo of ant leg on the DMD surface. Each mirror is 16 µm2 with 1µm separation between pixels

Digital Micromirror Device: an array of semiconductor-based digital mirrors that precisely reflect a light source for projection display and hard-copy applications. A DMD enables Digital Light Processing and displays images digitally. Rather than displaying digital broadcast signals as analogue signals, a DMD directs the digital signal directly to your screen.