Each pixel of a spatial light modulator comprises a movable mirror, a light sensitive element and control circuitry to drive an actuator set the movable mirror to a state determined by a signal received by the light sensitive element....http://www.google.com.au/patents/US7630118?utm_source=gb-gplus-sharePatent US7630118 - Spatial light modulator, method of spatially modulating a radiation beam, lithographic apparatus and device manufacturing method
