Sony Corporation

Hiroshi Oinoue

Akira Nakamura

Yoshiyuki Matsumoto

Hidehiro Kume

Koji Mitsumori

You Yoshitoshi

Etsufumi Yamamoto

Minoru Hashimoto

Tokio Kanada

Kenji Shintani

Shiro Morotomi

Yoshimasa Goda

Tsutomu Mochizuki

Tomoyuki Ishida

Genichi Iizuka

Junichi Usui

Takeo Tamura

Kunihiro Shioura

Shinichi Maru

Toshihiko Konno

The invention provides a reproduction apparatus that reproduces information recorded in a recording medium having plural recording layers, including: an optical head that irradiates laser beams on the respective recording layers and detects reflected light information to read out information recorded in the respective recording layers; a shaft sliding type focus actuator that holds the object lens; a focus servo section that generates a focus servo drive signal and drives the focus actuator such that a focus state of the laser beams is kept in a state of focus on a recording layer on which the reproduction is performed; and a focus jump control section that generates a kick signal for starting focus jump movement by the focus actuator and a brake signal for ending the focus jump movement.

Reproduction apparatus and focus jump method

An acoustic apparatus comprises an attenuator for attenuating a first audio signal to produce a second audio signal, a low pass filter for reducing high frequency components of the second audio signal to produce a third audio signal, a differential amplifier operative to produce a fourth audio signal corresponding to a difference between the first and third audio signals, and a speaker supplied with the fourth audio signal obtained from the differential amplifier, wherein a cutoff frequency of the low pass filter is selected to be not lower than 2 kHz and not higher than 6 kHz and attenuation of the first audio signal in the attenuator is so selected that a listener is able to recognize a virtual sound source position in front of and at a level higher than an actual position of the speaker.

Apparatus for adjustable positioning of virtual sound source

An optical pickup in an optical disc device configured for recording and/or reproducing signal on or from an optical disc. The optical pickup is configured for setting the orientation of a bending mirror directing the optical path of a light beam radiated from a light source towards the optical disc so that the optical path between the reflecting surface of the mirror and the photodetector is approximately 45 relative to the recording track of the optical disc. With the above configuration of the optical pickup, focusing error signals and tracking error signals of plural discs of different types can be detected by a common photodetector.

Optical pickup and optical disc device for accessing media of differing

Compact optical pick-up lead with a vertically inclined substrate

A disc driving apparatus comprising an optical head as a record/reproduce means for recording information on and/or reproduce the same optically from a disc type recording medium;a feed motor as a feed means for moving the optical head toward the innermost or outermost region of the disc; a limit switch as a detector means for detecting that the optical head is placed at a first position proximate to the innermost region of the disc; and a butt member as a positioning means formed to butt against the optical head for limiting the motion of the optical head at a second position in the innermost region of the disc. The speed of the optical head being moved toward the innermost region of the disc by means of the feed motor is changed to a lower speed in synchronism with turn-on of the limit switch, and then the optical head is brought to a halt at the predetermined position limited by the butt member, whereby the optical head is placed exactly at the desired position.

Disc driving apparatus having means for placing a read record head at a

A recording and/or reproducing apparatus for from an optical disk includes a tracking error signal forming device for forming a tracking error signal by taking the difference of detection output signals from at least a pair of light beam detectors provided in an optical pickup having an actuator for shifting an objective lens in a focusing direction or in a tracking direction. Also provided is, a tracking servo device for moving the objective lens in the tracking direction on the basis of the output signal from the tracking error signal forming device to effect a tracking servo, a period detection device for detecting whether the period of a tracking servo indicating a relative movement between a track on an optical disk and a light beam from the optical disk is not more than a predetermined value, and a d.c. component switching device for switching the gain of an amplifier stage stepwise, with the amplifier stage being adapted for amplifying a detection output signal of one of at least a pair of light beam detectors and supplying the amplified signal to the tracking error signal forming device. An offset eliminating device controls the d.c. component switching device to effect switching of the gain of the amplifier stage stepwise to produce compensation data compensating the offset of the tracking error signal, only when the detection output from the period detection means indicates that the traverse signal is not more than a predetermined value, with the tracking servo means being off.

Tracking error detection apparatus for an optical disk

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 device comprising an objective lens having an optic axis for focusing a light beam emitted from a light source on an optical recording medium. The objective lens is carried on a support member which is coupled with a base through a coupling unit. The coupling unit has a first rotation axis parallel to the optic axis for permitting rotation of the support member about the first rotation axis in a tracking direction perpendicular to the optic axis and a second rotation axis perpendicular to the optic axis for permitting rotation of the support member about the second rotation axis in a focusing direction parallel to the optic axis. The support member has a center of gravity positioned substantially on the first rotation axis. A light beam reflected from the optical recording medium is sensed for exerting a force on the support member to move the objective lens in the focusing and/or tracking directions so as to adjust the optic axis to a desired position.

Optical pickup device with objective lens movable in two directions

In a semiconductor laser apparatus for an optical head, a beam splitter having a first surface incline at a predetermined angle with respect to a radiant surface of a semiconductor laser chip is fixed on a photodetector to reduce the cost of the optical head.

Semiconductor laser apparatus for optical head

In an optical head having a plate-like half mirror functioning both as a beam splitter and for producing an astigmatism usable in detecting a focusing error, an optical element is provided for correcting a coma introduced by the half-mirror. Such optical element for correcting coma desirably includes a plate-like element inclined oppositely to the plate-like half mirror in respect to an optical axis of the head.

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Tokyo, Japan

Hiroshi Oinoue