Thin film actuated mirror array having an improved optical efficiency

Abstract

An array of M.times.N thin film actuated mirrors for use in an optical projection system, comprises an active matrix, an array of M.times.N actuating structures, an array of M.times.N mirror layers and an array of M.times.N supporting members. Each of the actuating structures includes a first and a second identically structured actuating parts, each of the first and second actuating parts having at least a thin film layer of a motion-inducing material, a first and a second electrodes. The first electrodes from each of the first and second actuating parts are physically joined, thereby serving as the common bias electrode, and the second electrodes function as the signal electrode. Furthermore, each of the mirror layers is divided into a first and a second reflectors. Each of the reflectors is provided with a first surface, a second opposing surface and a central tab portion therebetween. The central tab portion of each reflector is directly secured on top of each actuating part such that when the central tab portion in each of the reflectors deforms in response to an electrical signal, the first and second opposing surfaces in each of the reflectors tilt while remaining planar, thereby allowing all of the first and second opposing surfaces to reflect light beams, resulting in an increased optical efficiency.