Mirrors on a chip

The design, development, and performance of the digital micromirror device (DMD), a spatial light modulator for projection displays, are examined. The DMD covers each memory cell of a CMOS static RAM with a movable micromirror. Electrostatic forces contingent on the data in the cell tilt the mirror either on or off, modulating the light incident on its surface. Light reflected from any on-mirrors passes through a projection lens and creates images on a large screen. Light from the remaining off-mirrors is reflected away from the projection lens and trapped. The standard-resolution version of the DMD corresponds to the National Television System Committee (NTSC) or Phase Alternation Line (PAL) standard. It is a chip about 2.3 cm² covered by 442368 movable mirrors, each 16 μm on a side