Sony Corporation

Yoji Ishii

Kenji Kasahara

Naoki Inoue

Kiyoshi Ohsato

Shigeaki Koike

Teruaki Higashihara

Disclosed is an information recording/reproducing device using an upright disk-like recording medium contained in a cartridge, wherein an objective lens is stably moved in the tracking direction with less undesirable displacement and also the entire optical head portion including the objective lens is prevented from being undesirably moved. The device includes a disk mounting portion on which a disk contained in a cartridge is mounted with a recording surface portion located within a vertical plane, an optical head portion having an objective lens opposed to the recording surface portion of the disk, and an optical head drive portion, a tracking control portion, and a cartridge housing portion for housing and supporting the cartridge containing the disk when the disk is mounted on the disk mounting portion. The cartridge containing the disk is inserted into the cartridge housing portion in the direction crossing the vertical direction and the movement of the objective lens by the tracking control portion is performed in the direction perpendicular to the vertical direction.

Information recording or information recording/reproducing device

Laser light beams from first and second laser light sources 11 and 12 having different wavelengths are synthesized by a dichroic mirror 16 and irradiated on a magneto-optical disc 20 as a recordable disc and the reflected light is separated into the laser light of the first and second wavelengths. In respect of the laser light of the first wavelength, the phase difference between the P- and S-polarization components produced by the dichroic mirror 16 is compensated by a phase compensation plate 32 and the P-and S-polarization components are separated from each other by a polarization beam splitter 36 so as to be received by photodetector elements 37 and 38, respectively. Such dichroic mirror 16 is used in which the difference between the minimum transmittance in a working range of the laser light of the first wavelength and the maximum transmittance in a working range of the laser light of the second wavelength is 90% or higher for reducing changes in the phase difference between the P- and S-polarization components. Optimum signals may be obtained at the photodetector elements 37 and 38 while high wavelength separation characteristics are maintained.

Growing community of inventors

Kanagawa, Japan

Yoji Ishii