Patent ID: 6396791
Filing Date: 2002-05-28
Classification: G11B

Abstract:
An optical pick-up apparatus, to read two different kinds of first and second optical discs being different in substrate thickness and wavelength to be used, comprising:light sources which generate light beams respectively corresponding to said two kinds of optical discs; a photo detector to detect signal lights reflected on said two optical discs; and an opening limiting portion set slantwise to a light axis at a given angle, wherein one condenser lens condensing the light beam emitted from the light source corresponding to the first optical disc most suitably on the first optical disc is disposed, said opening limiting portion includes a plano-concave lens formed with a plane surface and a concave surface and is disposed between said condenser lens and said light sources, a beam diameter and a beam diffusion angle of the light beam emitted from the light source corresponding to the second optical disc are limited by said opening limiting portion, and said condenser lens condenses the limited light beam most suitably on the second optical disc.