Patent ID: 6282165
Filing Date: 2001-08-28
Classification: G11B

Abstract:
An optical recording/reproducing apparatus comprising:an irradiation optical system for irradiating a light beam from a light source onto a predetermined track of an optical recording medium having a plurality of neighboring tracks as a fine light spot so as to perform recording/reproduction of information or reproduction of information;a detection optical system for detecting a returned light beam from the optical recording medium, said detection optical system including a first photodetector for detecting a reproduction signal of information and a second photodetector for detecting a position signal in a direction perpendicular to the track on a surface of the optical recording medium; andmask means, arranged in a far field region sufficiently separated from a focal plane of said detection optical system in an optical path of said detection optical system, for masking marginal rays, in the direction perpendicular to the track, of the returned light beam,wherein said mask means satisfies the following relation:0.74-0.21*(d1/p)<B1/A1<1.09-0.21*(d1/p)for0<B1/A1<1whereA1: the beam diameter of the returned light beam in the direction perpendicular to the trackB1: the aperture width of said mask means for masking the returned light beam in the direction perpendicular to the trackd1: the 1/e.sup.2 diameter of the light spot on the optical recording medium in the direction perpendicular to the trackp: the track pitch of the optical recording mediumwhereby information reproduced by a side lobe of the light spot from a track adjacent to the predetermined track upon reproduction of information of the predetermined track by the light spot is reduced.