Method and apparatus for optical code reading using a mem optical

Abstract

An optical code reader comprises an integrated optical resonator that is disposed within a housing and that includes a substrate, a cantilever beam, and a bimorph actuator. The cantilever beam is affixed at one end to the substrate, and at least a portion of the cantilever beam has a reflective transmit surface on one side and a photodetector on an opposite side. The bimorph actuator is affixed to the cantilever beam and is responsive to an electrical stimulus to cause the cantilever beam to move in accordance with the stimulus. Movement of the cantilever beam causes the reflective surface to cooperate with a light beam generated by a light source to provide a spot of light that moves on a code pattern, and also causes a field of view of the photodetector to be dynamically altered such that the photodetector tracks movement of the moving spot of light. Additionally, the code reader also comprises a reflective collection surface having a conical shape, and the photodetector is located approximately at a focal point of the reflective collection surface. The combination of these features permits a high signal-to-noise ratio to be achieved, so that the code reader exhibits superior operating characteristics as defined by long read range and large depths of field. The disclosed optical code reader is structurally reliable, low cost and small size, has improved scalability, has minimal power requirements, and uses only a minimal number of discrete components.