OPTICAL PICK-UP DEVICE

摘要

PURPOSE: An optical pick-up device using laser not exceeding 500nm is provided to record or reproduce information in a media with high density by correcting a chromatic aberration efficiently with a collimating lens. CONSTITUTION: A light source(104) generating laser not exceeding 500nm is set on an optical axis of an objective lens(101). A 1/4 wavelength board(107), an optical splitter(102), and a collimating lens are located between the objective lens(101) and the light source(104). The collimating lens(103) is equipped with a positive lens(103a) and a negative lens(103b). An optical detector(106) is set at the end of the path of the reflected light from the optical splitter(102) and a focusing lens(105) is located between the optical detector(106) and the optical splitter(102).