Deflection plate for optical pick-up device

摘要

A deflection plate for deflecting laser beams includes a transparent plate on which two grating areas are formed on the same surface. The first grating area has a plurality of parallel grooves. The second grating area has a plurality of grooves in a predetermined pattern. The depth and/or the duty ratio of the grooves in the first grating area differs from that in the second grating area.