Deformable mirror display with continuous reflecting surface micromachined in silicon

Abstract

A novel micromachined deformable mir- ror display device (DMD) is proposed and character- ized. The principle of operation of DMD differs from that reported in (l). The DMD consists of a freely suspended silicon nitride/Al reflective flexible mem- brane, optical figure of which is controlled electro- statically by the array of integrated electrodes (2, 31. The local curvature of the membrane is proportional to the square of the voltage distribution on the ar- ray of electrodes. The light intensity in the near field of the collimated beam, reflected from the deformed membrane is modulated with the depth of modula- tion being approximately proportional to the mem- brane local curvature. The intensity distribution in the near field of the reflected beam follows approxi- mately the voltage distribution applied to the array of control electrodes. In contrast to (l) the device has 100% pixel fill factor. Contrast ratio of 3 : 1 and resolution of N 100 by 100 pixels with response time of N lms have been demonstrated experimentally.