Hitachi Consumer Electronics Co., Ltd.

Hitachi Media Electronics Co., Ltd.

Hitachi-lg Data Storage, Inc.

Nobuo Nakai

Toshiteru Nakamura

Shigeharu Kimura

Koichiro Nishimura

Kazuyoshi Yamazaki

Taku Hoshizawa

Koji Fujita

Takeyoshi Kataoka

Hirofumi Taguchi

An optical information recording and reproducing device that records information on a recording medium and/or reproduces information on the recording medium, using holography is configured to include a laser light source that performs irradiation with laser light, a first light-shielding portion which is capable of switching between transmission and shielding of laser light emitted from the laser light source, and a driving circuit that drives the switching between transmission and shielding of the first light-shielding portion, and a first movement portion that moves the first light-shielding portion.

Optical information recording and reproducing device, optical information recording and reproducing method

According to the present invention, of all beams of light reflected from the optical disc, only light in a peripheral region excluding a push-pull region is used to generate a DPD signal. In this method of signal generation that optimizes internal light-receiving surface interconnections in a photodetector, the lens error signal required for the generation of a tracking error signal in the DPP scheme is amplified at a lower amplification factor. In addition, the light reflected from the multilayered optical disc will be divided into a plurality of regions and the divided beam of light will be focused at different positions on the photodetector. When the beam is focused upon a desired layer, stray light from recording layers other than those to be subjected to information reproduction will not enter the photodetector light-receiving surfaces used for servo signals.

Optical pickup device and optical disc apparatus using same

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

Of the beams reflected by an optical disk, only peripheral beams excluding the push-pull region are used to generate a DPD signal in order to optimize internal wire connections among the light receiving areas of the optical detector and thereby reduce the amplification factor of the lens error signal, required for generating the tracking error signal of the DPP method. A beam reflected from a multilayered optical disk is divided into some beam diffraction areas. The divided beam diffraction areas and the light receiving areas are so arranged that the divided beams focus at different positions on the optical detector and that, when a beam is focused on a target recording layer of the disk, stray light from other than the target recording layer being reproduced does not enter into the servo signal light receiving area of the optical detector.

Optical pickup device and optical disk device using the same

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Yokohama, Japan

Nobuo Nakai