Matsushita Electric Industrial Co., Ltd.

Panasonic Corporation

Tetsuo Saimi

Yoshiaki Komma

Seiji Nishino

Hiroaki Yamamoto

Hidenori Wada

Shin-ichi Kadowaki

Daisuke Ogata

Teruhiro Shiono

Makoto Kato

Keiichi Matsuzaki

Kazuo Momoo

Shin-ichi Tanaka

Seiji Nishiwaki

Sadao Mizuno

Ryoichi Imanaka

Yasuo Nishihara

Hiroshi Yamamoto

Tohru Nakamura

Yasuhiro Tanaka

Ken'ichi Kasazumi

Shunji Ohara

Akihiro Arai

Kenichi Kasazumi

Kenji Nagashima

Shinichi Kadowaki

Masanari Mohri

Keiichi Yoshizumi

Yoshikazu Hori

Masatoshi Yajima

Yoshihiro Okino

Naoya Hotta

Shoji Goto

Yoichi Saito

Hiroshi Kayama

Shoji Gotoh

Akihiro Sakata

The invention presents an optical element with which an optical head can be configured, in which there is little deterioration of the correctional effect when the objective lens shifts, as well as an optical head and an optical recording/reproducing apparatus using such an optical element. The invention also presents a novel optical recording/reproducing apparatus and optical recording/reproducing method. The optical element, includes a first voltage application electrode, a first opposing electrodearranged in opposition to the first voltage application electrode, and a first phase changing layerarranged between the first voltage application electrodeand the first opposing electrode. By changing a voltage between the first voltage application electrodeand the first opposing electrode, a phase that converts plane waves into spherical waves is imparted on light that is incident on the first phase changing layer

Optical element, optical head, optical recording reproducing apparatus and optical recording/reproducing method

An information recording mediumincludes: a transparent substratehaving a first surface A and a second surface B opposite to the first surface A; reflectance reduction meansprovided on the first surface A of the transparent substrate; and an information recording layerprovided on the second surface B of the transparent substrate

Information recording medium and information recording/reproducing apparatus to increase recording density

The optical information recording and reproducing apparatus includes a light source for emitting a light beam, an objective lens for converging the light beam emitted from the light source to an information recording medium, and a light detector for detecting the light beam reflected from the information recording medium. The information bits are recorded into a recording member of the information recording medium in a three-dimensional arrangement by using a change in optical constant of the recording member. Furthermore, a thickness of the recording member is larger than a wavelength of the light beam and the information bits are sequentially recorded into the recording member in a three-dimensional arrangement in such an order that a converging light beam from the objective lens does not pass through information bits that have already been recorded.

Optical information recording and reproducing apparatus for recording information bits into an optical disk in a three dimensional arrangement

Optical element, optical head, optical recording reproducing apparatus and optical recording/ reproducing method

A returning light beam emitted by a light source and reflected by an optical disk is separated by a half mirror, and partitioned and deflected at a hologram into a light beam passing a first region and a light beam passing a second region. The light beam passing the first region is received by a plurality of photo-detectors, and the aberration is detected by comparing the resulting signals. Based on the aberration detection, the aberration of an optical system can be reduced by driving an aberration correction element in real-time.

Aberration detection device and optical information recording and reproducing apparatus

An optical head with high light utilization efficiency that includes a diffractive optical element and a light source emitting beams with a plurality of wavelengths that can read plural types of information recording media. A beam emitted from a light source selectively emitting a beam with a first wavelength and a beam with a second wavelength that is approximately twice as long as the first wavelength is collimated into a parallel beam by a diffraction collimator lens, is bent by a mirror for bending an optical path, and then is focused by a diffraction objective lens on an information recording medium. Outgoing light from these diffractive lenses is substantially a second-order diffraction light with respect to the beam with the first wavelength and is substantially a first-order diffraction light with respect to the beam with the second wavelength.

Optical head for a plurality of types of information recording media

An optical recording and/or reproduction apparatus includes: a light source for emitting a first light beam; an optical system for outputting first and second diffracted light beams and a second light beam; and a controlling section for controlling the optical system, wherein the first and second diffracted light beams interfere with each other to generate interference fringes which extend in a direction substantially perpendicular to a recording layer of an recording medium, the optical recording and/or reproduction apparatus further includes a detection section for detecting the interference fringes reflected by the guiding portion so as to output a detection signal, and the control section controls the optical system based on the detection signal such that the optical spots follow at least either of concave portions and convex portions of the guiding portion.

Optical recording and/or reproduction apparatus, tracking method, and optical recording medium

An information recording/reproducing apparatus determines whether ejection of an optical disk stored in an optical disk drive or in a changer is allowed when receiving a command for ejecting the optical disk to the outside. The information recording/reproducing apparatus allows the optical disk to be ejected only when judging that the ejection is allowed. When judging that the ejection is not allowed, the information recording/reproducing apparatus rejects the ejection. Prohibition of ejection of an optical disk on which information whose copyright is to be protected has been recorded enables the use of the information for private hobby and at the same time prevents pirated versions or the like from being produced, thus realizing copyright protection.

Information recording/reproducing apparatus

An optical head according to the present invention includes: a first light source for emitting light with a first wavelength; a second light source for emitting light with a second wavelength longer than the first wavelength; and an objective lens for focusing the lights with the first and second wavelengths on information recording surfaces of information recording media corresponding to the lights with the respective wavelengths. The objective lens is designed so as to reduce aberration with respect to the light with the first wavelength. An optical-path length from the second light source to the objective lens is allowed to be shorter than that from the first light source to the objective lens so that aberration caused by the objective lens due to chromatic dispersion caused by a material of the objective lens is reduced with respect to the light with the second wavelength. Thus, using a common optical system, recording and/or reproduction can be carried out with respect to the respective information recording media corresponding to the first and second wavelengths. Furthermore, since the common optical system can be used, the optical head can be simplified in configuration and can be reduced in size.

Optical head and recording reproduction method

An information recording and reproducing apparatus in accordance with the present invention has a radiation light source, a collimator turning a light beam emitted from the radiation light source into substantially parallel light, a light beam convergence member focusing the light beam on an information carrier, a light beam polarization-branching member branching the light beam by polarization, a variable wave plate located between the collimator and the light beam convergence member, photo detectors receiving the light beam branched by the light beam polarization-branching member and outputting a current according to an incident light quantity, and an output level judging member judging whether an output of the photo detectors is larger or smaller than a predetermined value. When the photo detectors receive a small light quantity because the information carrier is highly birefringent, the variable wave plate is switched from a &frac14; wavelength plate to a zero-wave plate, thus constantly obtaining a stable reproducing signal with an excellent S/N.

Information recording and reproducing apparatus

Growing community of inventors

Hirakata, Japan

Tetsuo Saimi