Matsushita Electric Industrial Co., Ltd.

Panasonic Corporation

Seiji Nishino

Yoshiaki Komma

Hiroaki Yamamoto

Hidenori Wada

Shin-ichi Kadowaki

Teruhiro Shiono

Tetsuo Saimi

Kousei Sano

Ken'ichi Kasazumi

Sadao Mizuno

Daisuke Ogata

Makoto Kato

Keiichi Matsuzaki

Tatsuo Ito

Tatsuo Itoh

Shinichi Tanaka

Seiji Nishiwaki

Kazuhisa Yamamoto

Shinichi Kadowaki

Hideki Hayashi

Yoshikazu Hori

Kaoru Matsuda

Kenichi Kasazumi

Takashi Hirao

Kiyotaka Wasa

Takeo Ohta

Masanari Mohri

Tsuneo Mitsuyu

Akihiro Yasuda

Katsuhiko Yasuda

Yuzo Takada

Atsuo Nishikawa

An information recording medium of the optical information reproduction device of the present invention includes a recording unit capable of recording information three-dimensionally and provided with a track, and information is recorded by forming a plurality of recording marks along the track of the recording unit by a mark length recording method. When the track direction of the recording marks is assumed to be their longitudinal direction and the direction perpendicular to the track direction is assumed to be their lateral direction, with the present invention, for recording marks located substantially in the same plane, the total area of elongated recording marks, whose longitudinal length is greater than their lateral length, is greater than the total area of recording marks having other than elongated shapes. The optical information reproduction device of the present invention includes a first light source for emitting a reproduction light having a wavelength &#x3bb;, an objective lens for focusing the reproduction light on the recording unit, and a first photodetector for detecting a reproduction signal from the reflected light from the recording unit. The focused reproduction light includes as its main component a polarized light component that is polarized perpendicular to the track direction. Also, the recording unit has a track pitch of no more than 1.3 times the wavelength &#x3bb;of the reproduction light.

Optical information reproduction device

An information recording medium includes a substrate and a recording portion having recording layers on the substrate, wherein the recording portion is capable of three-dimensional recording by changing an optical constant of the recording layers by irradiation of recording light, and a first reflected-light reducing portion for reducing reflected lights of reproducing light from the substrate side is provided at a side opposite to an incident side of the reproducing light with respect to the recording portion, and an optical information recording/reproducing apparatus records and reproduces information to and from the medium.

Information recording medium and optical information recording/reproducing apparatus

A laser beamreflected by an information layer of a multilayer optical discis reflected and split by reflecting surfacesandto be incident on a photodetector elementas laser beamsand. The laser beamis collected on a light receiving regionfor RF detection to generate an RF signal. The laser beamsare incident on light receiving regionsfor focus detection, and a focus error signal is generated by an SSD method. A laser beamreflected by an information layer adjacent to the above information layer partially transmits through the reflecting surface' to be imaged on a light receiving regionfor tracking detection, and a tracking error signal is generated.

Optical head device and optical information processor

In a confocal optical system having a light source, a first focusing means, a second focusing means, an aperture, and a detectorincluding a plurality of light reception regions, a position displacement is detected by detecting an intensity distribution of an image caused by a position displacement between a focusing spot of the second focusing meansand the aperture, by the detector. Further, the position displacement is corrected by controlling the aperture position using driving meansand control means. Also, a position displacement of the aperturein the optical axis direction is detected and corrected on the basis of a change in an output of the detectorby oscillating the aperturein the optical axis direction.

Confocal optical system aperture detector that measures a light quantity balance of light received to detect a position displacement, and a confocal optical system aperture position controller, an optical head and a position detecting method performing the same

A compound objective lens is composed of a hologram lens or transmitting a part of incident light without any diffraction to form a beam of transmitted light and diffracting a remaining part of the incident light to form a beam of first-order diffracted light, and an objective lens for converging the transmitted light to form a first converging spot on a front surface of a thin type of first information medium and converging the diffracted light to form a second converging spot on a front surface of a thick type of second information medium. Because the hologram selectively functions as a concave lens for the diffracted light, a curvature of the transmitted light differs from that of the diffracted light. Therefore, even though the first and second information mediums have different thicknesses, the transmitted light incident on rear surface of the first information medium is converged on the its front surface, and the diffracted light incident on a rear surface of the second information medium is converged on the its front surface. That is, the compound objective lens has two focal points.

Objective lens for optical disks having different thicknesses

An optical disk device is provided with an optical pickup that includes a convergent optical system having an objective lens for converging a light beam emitted from the laser light source to form a microspot on an optical disk and an aberration correcting optical system for controlling a spherical aberration of the convergent optical system, and performs information recording or reproduction with respect to a multi-layer optical disk having at least a first recording layer and a second recording layer. In the optical disk device, an operation of changing a correction quantity of the spherical aberration from a value adequate for the first recording layer to a predetermined value is started before an operation of moving a focus position of the microspot from the first layer to the second layer is completed. This allows a focus control to be performed stably with respect to the second recording layer in a state in which the spherical aberration correction already has been carried out, thereby preventing the focus control from failing due to an unsuccessful interlayer jump.

Optical disk device and information recording/reproducing method

An optical recording medium which is a multilayer optical recording medium including a plurality of recording layers and records or reproduces information by the irradiation of light having a wavelength of &#x3bb;0. At least one recording layer out of a plurality of recording layers includes a variable absorption film. The variable absorption film contains a material in which an electron energy has a band structure, and the absorption end of an absorption spectrum moves toward a longer wavelength side with a rise in temperature when light is absorbed by transition between electron bands, has a first absorptance to light having a wavelength of &#x3bb;0 when a film temperature is a first temperature (application environment temperature), and has a second absorptance higher than the first absorptance to light having a wavelength of &#x3bb;0 when a film temperature is a second temperature higher than the first temperature.

Optical recording medium, optical information processor, and optical recording/reproducing method

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 optical head device includes a focusing optical system for focusing a laser beam emitted from a semiconductor laser light source on an optical information medium with an objective lens. A chromatic aberration correction element for correcting chromatic aberration occurring in the objective lens is provided between the semiconductor laser light source and the optical information medium. A light distribution correction element in which the transmittance increases with the distance from the center of the aperture surface of the objective lens is provided so as to correct a reduction of the intensity of the light incident on the aperture surface of the objective lens with the distance from the center of the aperture surface.

Optical head device and optical information apparatus using the same

An optical head with excellent optical characteristics even when using a light source that substantially has a wavelength broadening is provided. The optical head includes a light source, an objective lens for focusing a light beam emitted from the light source on an information recording medium and a photodetector for detecting the light beam reflected from the information recording medium, wherein defocusing correction means and spherical aberration correction means are provided in an optical path between the light source and the information recording medium. Since both the defocusing correction means and the spherical aberration correction means are provided, while defocusing of a focused spot on the information recording medium caused by a wavelength broadening of the light source and chromatic aberration of the optical system can be corrected, the spherical aberration of the optical system caused by wavelength difference between a design wavelength and an incident wavelength also can be corrected. As a result, excellent optical characteristics can be obtained.

Optical head with spherical aberration correction and method of using same

An object of the present invention is to acquire optimum recording characteristics of an optical recoding medium having multiple data layers, with respect to each of the multiple data layers without increasing learning time required for learning a relation between aberration amount and optimum recording compensation with respect to each of the multiple data layers. The present invention includes a wavefront converter which is driven in such a manner as to reduce the aberration amount detected by an aberration detector. An output controller holds learned data as to the relation between the driving amount of the wavefront converter and the output of a light source, and controls the output of the light source based on the driving amount of the wavefront converter and the learned data.

Optical head device, optical recording device, and optical recording method

An information recording medium has a recording portion where three-dimensional information can be recorded. The recording portion includes at least one particle-containing layer (recording layer or a recording auxiliary layer) containing particles absorbing at least a part of light having a predetermined wavelength and substantially transparent to a recording light and a reproducing light having a wavelength longer than the predetermined wavelength and a particle holding material substantially transparent to the recording and reproducing lights. The mean particle size of the particles is preferably shorter than the wavelengths of the recording and reproducing lights.

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Osaka, Japan

Seiji Nishino