OPTICAL PICKUP FOR HIGH DENSITY RECORDING/PLAYBACK

摘要

PURPOSE: An optical pickup for high density recording/playback is provided to compact structure, to be insensible to the tilt of an incident light, and to obtain high numerical aperture by adopting a single lens. CONSTITUTION: An optical pickup includes an optical module(21) for exiting a light and receiving the light reflected onto a recording medium and a solid immersion lens member(30) placed on a light path between the optical module and the recording medium. The solid immersion lens member includes a first solid immersion lens portion(31) having a planar surface(31a) facing the recording medium and a specific refractive index and a second solid immersion lens portion(33) having a specific refractive index. The refractive index of the second solid immersion lens portion is larger than that of the first solid immersion lens portion. The solid immersion lens member forms a light spot on the writing surface of the recording medium by focusing incident lights. Since a curved surface(33a) of the second solid immersion lens portion is oval, spherical aberration is restrained. A boundary surface(35) of the first and second solid immersion lens portions is non-spherical. Thus, coma aberration due to the tilt of an incident light is avoided.