Hitachi-lg Data Storage, Inc.

Hitachi, Ltd.

Hitachi Consumer Electronics Co., Ltd.

Takeyoshi Kataoka

Motoyuki Suzuki

Yoshinori Ishikawa

Tsuyoshi Toda

Yutaka Nagai

Nobuhiro Takeda

Fumio Isshiki

Kenji Akahoshi

Takakiyo Yasukawa

Hiroharu Sakai

Toru Kawashima

Seiji Imagawa

Nobuo Nakai

Munehiro Yonezawa

Kenichiro Yamada

An optical disk device for recording/reproducing information on/from a multi-layer optical disk moves a light focusing point for several layers by one focus jump. The optical disk device includes a controller to detect a level of a focus error signal to change an output level of a focus drive signal, and the controller changes timing to change the output level of the focus drive signal based on the number of layers for the focus jump.

Focus jump method for optical disk device and multi-layer disk

In an optical disk having multiple layers for which a correction of spherical aberration is required, a spherical aberration correcting element is set to a predetermined spherical aberration correction amount; a laser light source is turned ON; an objective lens is swept; when it is discriminated that the optical disk has two or more layers, or has more than two information recording planes, the spherical aberration correction amount is changed into a spherical aberration correction amount suitable for information recording planes of three, or more layers; and the objective lens is again swept so as to discriminate a total layer number thereof.

Optical disc apparatus and optical disc discriminating method

An optical disk discriminating method and an optical disk device which can detect reflected rays for making discrimination among kinds of optical disks with high accuracies. By switching a plurality of lasers and moving a spherical aberration corrector while moving an objective lens to cause it to approach or keep away from an optical disk, rays reflected light from the optical disk can be detected with high accuracies. Discrimination among the kinds of a plurality of optical disks can be made on the basis of signals generated from the detected reflected rays. This ensures that the kind of an optical disk can be determined through one operation of sweeping.

Optical disk device and optical disk discriminating method

An optical disc device capable of preventing a current larger than prescribed in specifications from flowing by measuring amounts of variation in drive signals of the actuator or the spindle motor, and in view of a correlation between those amounts of variation in the drive signals and the amount of current, changing the servo control system characteristics according to measured amounts of variation, and setting a limit to the level of drive signals.

Optical disc device

Where a hybrid disc has different types of media, the light spot moves among recording layers of the different media, after loading the disc into an optical disc apparatus, there is a problem that information on a media type of each recording layer should be recorded in DI etc. of the optical disc. Detailed information on the hybrid disc is stored in DI, by changing a disc layer type identifier or a disc structure in DI such as BCA or PIC on the optical disc.

Optical disc reproducing apparatus for implementing an optical recording and reproducing method for multi-layer optical discs

There is a need to provide correction of a temperature characteristic of an optical pickup of an optical disk recording/reproducing apparatus, in which items of the optical pickup including spherical aberration may be improved in temperature characteristic. To achieve the need, an optical disk drive is characterized by correcting a spherical aberration correction element when variation of a signal from the control circuit to the driver and/or a tracking or focusing error signal supplied to the controller has a value equal to or more than a predetermined value.

Correcting temperature characteristic of optical pickup of an optical disk recording/reproducing apparatus

An optical disk device for recording or reproducing an optical disk has: an objective lens for irradiating a laser beam to the optical disk; an actuator for moving the objective lens in the radial direction of the optical disk; and a spindle motor for rotating the optical disk. After the laser beam irradiated to the optical disk passed through a PID portion of the optical disk, the actuator moves the objective lens in the radial direction of the optical disk at a timing corresponding to a rotational speed. Between signals to drive the actuator, an output time of a deceleration signal is set to a predetermined ratio of a time during which an acceleration signal is outputted. While the deceleration signal is outputted, a light spot passes through the PID portion.

Optical disk apparatus with an improved track jump performance

When record or reproduction quality of an optical disc is deteriorated, an enhancement in the performance is implemented by slowing down record or reproduction speed of the optical disc. However, there still exists a problem of how to select and determine a timing with which the speed is to be modified. In the present invention, the modification of the speed is performed with a seek processing selected and used as its trigger, and depending on various conditions at that time. Simultaneously, information recording area of the optical disc is separated into a plurality of zones. Then, when an optical pickup passes though a zone switching portion therebetween, the seek processing is inserted, thereby being used as the trigger for the speed modification.

Optical disc device and optical disc record reproducing method

An optical disc apparatus including means for calculating a spherical aberration correction quantity of an object lens, reproduced information signal generation means and spherical aberration correction means conducts spherical aberration correction, finds a spherical aberration correction quantity suitable for another layer by calculation on the basis of the obtained spherical aberration correction quantity, and sets the correction quantity as an initial correction quantity of spherical aberration correction. An optical disc apparatus including tilt correction quantity calculation means, reproduced information signal generation means and tilt adjustment means conducts tilt adjustment, finds a tilt correction quantity suitable for another layer by calculation on the basis of the obtained tilt correction quantity, and sets the correction quantity as an initial correction quantity of tilt adjustment.

Optical disc apparatus for conducting information recording or reproduction on an optical disc

A focus-servo control method of an optical disc recording/reproducing apparatus, for recording or reproducing information onto/from an optical disc having a track with a land and a groove, which are formed in a spiral manner on an information recording surface thereof, the optical disc recording/reproducing apparatus including an objective lens, the method comprising steps of: moving an optical spot from the land to the groove or from the groove to the land through a L/G exchange portion therebetween and moving a position of the objective lens from a land position to a groove position by gradually changing a focus offset value for the land to a focus offset value for the groove from a position located before the L/G exchange portion, when the optical spot moves from the land to the groove.

Optical disc recording/reproducing apparatus and focus-servo method thereof

For achieving pulling operation into tracking servo during seek operation at high-speed and with stability, in timing thereof, even on an optical disk forming lands and grooves on a recording surface thereof, in a seek control method, according to the present invention, for moving an optical spot onto an arbitrary track through movement of an optical pickupinto the radial direction on the optical disk forming the lands and the grooves, thereby forming a track on the recording surface thereof, in particular, in the seek operation, measurement is made on a period of a tracking error (TE) signal generated due to the movement in the radial direction, and a time point when the measured period of the tracking error signal exceeds a predetermined value is determined to be a starting point for pulling the optical spot of the optical pickup into the track, through the tracking servo, thereby pulling it selectively, into either one of the land and the groove building up the track.

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Yokohama, Japan

Takeyoshi Kataoka