Matsushita Electric Industrial Co., Ltd.

Funai Electric Company Ltd.

Yuichi Kamioka

Shigeru Furumiya

Takashi Ishida

Shunji Ohara

Toyoji Gushima

Yoshinari Takemura

Yoshito Aoki

Kenji Koishi

Yoshiyuki Miyabata

Daisuke Ogata

Yuichi Takahashi

Toshiya Akagi

Yuji Hisakado

Chikashi Inokuchi

Naoyuki Nakamura

Kenichi Tatehara

Kiyoshi Nakamori

Ikuo Hidaka

Jun-ichi Ninamino

Takayuki Sakabayashi

In an optical pickup device including light sources for emitting laser light, an objective lens for collecting the laser light emitted from the light sources on a disc surface of an optical disc, a light receiving unit for receiving the reflected light reflected by the disc surface, a collimator lens for correcting spherical aberration of the exit light from the objective lens, a lens driving unit for moving the collimator lens in an optical axis direction, and a control unit for controlling the operation of the lens driving unit based on the output of the light receiving unit, the astigmatism of the exit light from the objective lens is corrected by tilting the collimator lens by a predetermined angle by the lens driving unit.

Optical pickup device

An optical pickup includes: a spherical aberration correcting portion for correcting spherical aberration by adjusting a convergence/divergence state of laser light emitted from a light source; a reflecting portion having: a first surface that chooses whether or not to pass laser light emitted from the spherical aberration correcting portion according to the wavelength of the laser light; and a second surface that reflects laser light that has passed through the first surface; and two objective lenses that are selectively used according to whether laser light reflected from the reflecting portion has been reflected by the first surface or by the second surface so as to condense light reflected from the reflecting portion onto a recording layer of an optical disc. Here, between the spherical aberration correcting portion and the objective lenses, there is disposed an astigmatism correcting portion that is formed such that the amount of correction can be changed.

Optical pickup and optical pickup aberration correcting method

A semiconductor laser driving apparatus for directing light to an optical disc for recording a recording mark based on a recording current and reproducing the recording mark to generate a reproduction signal. The apparatus includes a reproduction current generation section; a high frequency current generation section for generating a current including a high frequency component for reducing semiconductor laser noise in the reproduction; a recording current generation section, the recording current including a pulse corresponding to the recording mark and including a plurality of multi-pulses; and a current driving section for amplification. The apparatus further includes a filter to attenuate the enhanced high frequency components in the high frequency current and in the enhanced high frequency component; and a switching section for switching the filter so that the enhanced component in the recording current is superposed on at least one of the multi-pulses.

Semiconductor laser driving apparatus with filter to attenuate enhanced frequency component and optical disk apparatus including the same

An optical disk drive reads and/or writes data from/on an optical disk on which a pre-pit has been formed on at least one side edge of a data recording track. The disk drive includes light-emitting element, photodetector section, subtractor and amplifier. The light-emitting element emits a light beam and irradiates the track with the light beam. The photodetector section receives and detects the light beam reflected from the track, thereby generating first and second detection signals, carrying information about shapes of the track at the one and the other side edges thereof, respectively, based on the reflected light beam. The subtractor generates a differential signal representing a difference between the first and second detection signals. The amplifier amplifies the differential signal, output from the subtractor, by a variable amplification factor. The optical disk drive detects the pre-pit in accordance with the amplified differential signal.

Optical disk drive

Address groups are composed of two of address blocks , and , where the address blocks , and are disposed in a sector address region and include identifiable information of address numbers and overlapping sequential numbers . The address groups are disposed so that each group is alternately shifted from a track center toward the inner periphery side or the outer periphery side, by a width substantially equal to half the track pitch, along the radius direction.

Optical disk and a recording/reproduction apparatus using multiple address block groups shifted oppositely with multiple address blocks and non-pit data

Optical disk and a recording/reproduction apparatus using multiple address block groups shifted oppositely with multiple address blocks having clock synchronization, address number and address ID

Optical disk and a recording/reproduction apparatus using multiple address block groups shifted oppositely with multiple address blocks and clock synchronization

Optical disk and a recording/reproduction apparatus thereof

In an optical disc apparatus, a semiconductor SLD driving device is mounted on an optical pickup in order to realize a high speed switching of drive current for a semiconductor laser diode (SLD), necessary for recording data. The SLD is placed. within 5 cm from the SLD driving device. The driving device becomes a heat source due to driving current of the SLD, and increases a temperature of the optical pickup. Since the temperature rises proportionally to power consumption, power saving is required. A voltage supplied to the driving device is controlled to be a minimum level necessary for keeping the driving device still working on basic functions. The SLD driving device is mounted to the optical pickup, and this driving device handles N pieces of input signals for setting semiconductor laser power and N pieces of switch-timing-input-signals for selecting respective input signals. A supplied voltage is controlled so that a voltage supplied to the output section of the driving device is a minimum value necessary for keeping the output section still operating. A power source is placed outside of the pickup.

Semiconductor laser diode driving device and driving method

Address groups are composed of two of address blocks,, and,, where the address blocks,, and,are disposed in a sector address region,and include identifiable information of address numbers,and overlapping sequential numbers,. The address groups are disposed so that each group is alternately shifted from a track center,toward the inner periphery side or the outer periphery side, by a width substantially equal to half the track pitch, along the radius direction.

Optical disk and recording/reproducing apparatus using multiple address block groups shifted oppositely with multiple address blocks

According to the present invention, an optical disk recording method for recording data on an optical disk including a land and a groove by forming a mark representing the data on the optical disk by irradiating a light beam onto the optical disk is provided. In this method, conditions for irradiating the light beam are varied depending upon whether a position at which the mark representing the data is formed on the land or on the groove so that a size of the mark formed on the land is equal to a size of the mark formed on the groove.

Method and apparatus for recording data on an optical disk and or groove

When information is reproduced from an optical disk, a comparator compares a reproduced signal with a slice signal to generate binarized signals, while the slice signal is corrected continuously for external disturbances in a reproduced signal. A switch changes the time constant of the frequency response of the slice signal according to the reproduced signal. For example, the frequency response of the slice signal is set faster in a first region in a prepit area of the disk and in a record area of the disk so that the slice level converges quickly, while the frequency response is changed thereafter to a low time constant for normal signals. Thus, inaccuracy in binarization of the reproduced image signal is minimized, and the sector format is performed efficiently.

Method and apparatus for controlling a slice signal in the reproduction

A method for controlling intensities of a plurality of laser beams respectively emitted on a track of an optical disk by a plurality of laser diodes according to the present invention includes a step of performing focusing servo control for focusing one of the plurality of laser beams emitted by one of the plurality of laser diodes onto the track, and concurrently controlling an intensity of the laser beam emitted by each of plurality of laser diodes to be within a predetermined range by comparing a signal which is in accordance with an intensity of the laser beam emitted by that laser beam with a reference signal. A period during which the one of the plurality of laser diodes used for the focusing does not emit the one laser beam is shorter than a response time of the focus servo control.

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Katano, Japan

Yuichi Kamioka