A study on optical pickup actuator for small form-factor optical disc drives

摘要

Optical disc drives (ODDs) such as CD, DVD and HD-DVD are cheaper and more distributable than solid-state memories and hard disc drives (HDDs). In the era of mobile environment, ultra-slim ODDs have been studied and developed to show the feasibility of mobile application. This paper is a study on miniaturization of an optical pickup actuator, one of key components for ultra-slim ODDs. A newly configured actuator which is targeted to be installed in 5 mm height ODDs is presented in this work. In order to reduce the height of the optical pickup actuator, a novel structure of suspension is developed by arranging Ω-shaped plate-suspension at both sides of a moving part in same plane. Also, the reduction of unwanted resonance peak, which is one of main issues in optical pickup actuators, is attempted. The presented structure of suspension is optimized by finite element analysis in terms of linearity and damping characteristic that reduces the unwanted resonance such as the rolling, pitching modes. The electromagnetic circuits, which generate driving forces, are arranged for high sensitivity and the reduction of the unwanted resonances. Developed actuator is tested to confirm stable frequency response characteristics in focusing and tracking directions as well as low tilt characteristics. In addition, the actuator is mounted on a DVD pickup system and optical signal from this optical pickup is detected. This reveals the feasibility as an information storage for mobile devices.