Development of tracking and focusing micro actuators for dual-stage optical pick-up head

Abstract

This work presents a miniaturized tracking and focusing optical pickup head implemented using MEMS technology. The device was fabricated by poly-Si trench-refilled technology and used a UV-cured polymer droplet or micro ball lens as the objective lens. A bidirectional vertical comb-drive actuator and V-beam thermal actuator drove the objective lens for the out-of-plane (focusing) and in-plane (tracking) motion, respectively. In applications, various tracking and focusing devices have been successfully fabricated and characterized. The upward and downward displacement of the focusing optical pickup head is 2.9 and 1.7 µm, respectively; the in-plane displacement of the tracking optical pickup head is ± 46.7 µm. The resonant frequencies of the focusing and tacking systems are 2.3 and 8.5 kHz respectively. In addition, the UV-cured polymer lens and solid micro ball lens were both successfully integrated with a MEMS device to create an objective lens.