Sony Corporation

You Yoshitoshi

Yoshiyuki Matsumoto

Hidehiro Kume

Koji Mitsumori

Ryoji Takamatsu

Hiroshi Oinoue

Tsutomu Toyoguchi

Etsufumi Yamamoto

Masashi Nakamura

Kazuhiko Fujiie

Yasunori Terayama

Yoshiro Watanabe

A focusing error detecting apparatus having a first photo-detector of which the light receiving portion is halved to provide first and second light receiving portions asymmetrical with respect to the center of a beam spot of a bundle of incident laser beams, the first photo-detector being located in the optical path ahead of the focusing point of the bundle of the incident laser beams, a second photo-detector of which the light receiving portion is halved to provide first and second light receiving portions asymmetrical with respect to the center of a beam spot of a bundle of incident laser beams, the second photo-detector being located in the optical path behind a focussing point of the bundle of the incident laser beams and a calculating circuit for calculating a difference between a difference of detected outputs from the first and second light receiving portions of the first photo-detector and a difference of detected outputs from the first and second light receiving portions of the second photo-detector, thereby to derive a focusing error signal from the output of the calculating circuit.

Optical pickup device

An optical pickup device having a semiconductor laser element mounted on a substrate, a photo detector formed on the substrate to receive a laser beam emitted from the semiconductor laser element and an optical element mounted on the substrate to cover the photo detector to branch the direction of optical path of the laser beam, the optical element having its face opposing the semiconductor laser element formed as an inclined face on which a semitransparent reflection film is deposited. The optical path branching optical element is provided with preventing means by which, of laser beams incident on the optical element, a laser beam reflected and/or scattered within the optical element is prevented from irradiating the photo detector.

An optical pickup head comprising a substrate on which a optical sensor is formed, and an optical member adhered on said optical sensor on said substrate by an adhesive and including a semitransmissive reflective film adapted to reflect the light emitting from a laser source and to transmit the light returned from a second medium of a disk, characterized in that the refractive index of said optical member is set so as to be larger than the refractive index of said adhesive.

Optical pick-up head without pick-up of stray light

Focusing detection apparatus

An optical disk player wherein a chassis having an optical pickup, a disk table and the like mounted thereon is supported by a frame using elastic support means at a plurality of positions, a vessel filled with a viscous fluid and sealed is provided at either the frame or the chassis, and a movable member provided at the other of the two is arranged in the sealed viscous fluid. With this arrangement, the slope of the Q curve in the resonant region is moderate enough to improve the antivibration characteristics, thus substantially eliminating sound omissions.

Optical disk player

A semiconductor laser apparatus having a semiconductor laser diode for radiating a laser beam, a photodetector formed on a semiconductor substrate, a prism having a first plane for introducing the laser beam to a reflecting substance and introducing the beam reflected by the reflecting substance to the photodetector and a second plane facing to the photodetector, and a coating layer formed on the boundary between the semiconductor substrate and the prism, having a refractive index such that the laser beam incident from the first plane other than the laser beam reflected by the reflecting substance is inhibited from reaching the photodetector.

Semiconductor laser apparatus for optical head

An optical pickup of the invention has an objective lens holder holding an objective lens, a support shaft which supports the objective lens holder such that the holder is slidable along the axial direction and pivotable about its axis, and a press member for pressing the objective lens holder against the support shaft.

Growing community of inventors

Tokyo, Japan

You Yoshitoshi