Study of the laser feedback noise for the blue-light optical pickup heads

• Main Authors: Jau-Yang Jeng, 鄭朝陽
• Other Authors: 施錫富
• Format: Others
• Language: zh-TW
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/21264959782945430911

碩士 === 國立中興大學 === 機械工程學系所 === 96 === The traditional measuring system of laser feedback noise without the servo close-loop control is difficult to measure the real noise distribution of an optical pickup head while operating in an optical drive. For the reason, there is a literature that applied a dynamic method to measure the laser feedback noise. However, it is only applicable to a red-light optical pickup head and cannot be suitable to the next-generation blue-light system. In this study, we combine the idea of dynamic measurement with the blue-light optical pickup heads as our main system. We drive the focusing actuator by the servo controller to realize a dynamic real-time laser feedback noise measuring system and to investigate its noise distribution corresponding to the focusing error, rotation speed and laser power. The experimental results show that the laser feedback noise is responsible to the focusing point within the linear range of an optical pickup head, rotation speed and laser output power. Furthermore, we demonstrate that it is feasible to depress the laser feedback noise by inserting a quarter-wave-plate in the measuring system.