相变型双光路激光光盘位相延迟器件的设计

Design of a Phase-delay Element Used in Phase-change Disk with Two Beam Optical Head

相变型双光束光学头系统中，用到两块位相延迟器，即四分之一波片（ＱＷＰ）与二分之一波片（ＨＷＰ），其中ＱＷＰ的性能对系统的影响最大，包括光盘读出信号的信噪比（ＳＮＲ）以及伺服信号的质量。本文分析了常规波片的缺点，重点讨论了倾斜光轴波片的设计方法。

Two phase delay elementSλ/4 wave plate QWP and λ/2 wave plate HWP areused in the system of phase-change two beam optical head.The characteristes of QWPgreatly affect the feature of the system,including signal to noise ration(SNR)of readingsignal of optical disk and quality of servo signal.In this peper the defects of conventionalwave plate is analyzed,and the design consideration of a wave plate with titling optical axisare mainly discussed.