Combined Device of Optical Microdisplacement Sensor and PZT-Actuated Micromirror

A combined device of a PZT-film-actuated micromirror and microsensor that can detect linear movement and rotation angle of the mirror has been developed[l]. The micromirror is actuated by vertical movement of two PZT cantilevers formed as a unit on the right and left of the movable mirror and directly connected to it via hinges. By detecting reflected light diffused from a VCSEL (vertical-cavity surface-emitting laser) toward the mirror, using two photodiodes (one on each side), displacement and rotation angle are measured with high precision. Since this combined device can feed back the displacement and rotation angle obtained from the sensor, it can compensate for the hysteresis of PZT and therefore enable stable, high-precision optical beam control.