Pioneer Electronic Corporation

Pioneer Corporation

Pioneer Electronic Corporatioin

Yoshitsugu Araki

Takanori Maeda

Junichi Furukawa

Masakazu Ogasawara

Ikuya Kikuchi

Toshihiko Kurihara

Taichi Akiba

Masayuki Iwasaki

Mitsuru Sato

Kazuo Takahashi

Hajime Koyanagi

Kiyoshi Tateishi

Hiroki Kuribayashi

Takuma Yanagisawa

Makoto Sato

Masaru Ishikawa

Tadashi Funabashi

Katsuhiro Koike

Noriaki Murao

Sakashi Ootaki

Hideyuki Takeuchi

Yoshihisa Ito

The depth of pits is determined by a trade-off between the level of a push-pull signal used for servo application by a push-pull method and the level of an RF signal as a reproduced signal of information. The depth d is set to be the optimum for a disk system, which has a refractive index n of a medium, an optical wavelength &#x3bb;, and an optical system with a NA (Numerical Aperture) of 0.75. The most suitable depth d for both the push-pull signal level and the RF signal level falls within a range of &#x3bb;/5.5n&#x2266;d&#x2266;&#x3bb;/4.7n, the second most suitable depth d falls with a range of &#x3bb;/5.5n&#x2266;d&#x2266;&#x3bb;/4.5n, and the depth d as the widest standard falls within a range of &#x3bb;/8n&#x2266;d&#x2266;&#x3bb;/4.5n.

Information recording medium, information reproducing apparatus, information recording apparatus, and information recording/reproducing apparatus

An optical disc player executes a focus pull-in operation while avoiding an inconvenience that an objective lens comes into contact with an optical disc, or the like. The objective lens is forcedly moved gradually from a position that is away from the surface of the optical disc and outside a capture range of a focus servo toward the surface of the optical disc. When the objective lens reaches the capture range of the focusing servo loop by the moving operation and a distance between the objective lens and the disc surface is at the minimum distance or is changing in a widening direction, the moving operation of the objective lens is stopped.

Optical disc player with focus pull-in function

A light beam from a light source is introduced to a grating element of a pickup device to create zero order diffracted light, &#xb1;first order diffracted light, and &#xb1;second order diffracted light. An irradiation system focuses the zero order, &#xb1;first order and &#xb1;second order diffracted light onto tracks extending on a recording surface of an optical recording medium to form spots. A spot of the zero order diffracted light is formed on a target track, spots of the &#xb1;second order diffracted light are formed on tracks adjacent to the target track, and spots of the &#xb1;first order diffracted light are formed midway between the spots of the &#xb1;zero order and &#xb1;second order diffracted light. An optical system guides returning light reflected from the spots to an optical detector. The optical detector has independent light-receiving elements for receiving the returning light. A servo signal calculator creates an error signal based on the output signals from the optical detector. The pickup device can be used for various types of optical discs having different disc structures. The pickup device can obtain a tracking error signal by a differential push-pull (DPP) method whatever optical disc is recorded and played back. The optical pickup device can use a crosstalk cancel (CTC) method whatever optical disc is played back.

Optical pickup device driven by an error signal obtained from an optical detector's output signals

An information recording apparatus capable of detecting an accurate tracking error even if a reflectance or a transmittance of respective information recording layers varies when information is recorded onto a multilayer optical information recording medium having a plurality of information recording layers, wherein the apparatus comprises a detecting device for detecting a position of a boundary portion between a recorded area where the information has already been recorded and an unrecorded area in the information recording layer; an inhibiting device for inhibiting recording the information onto an area in one information recording layer in a case where the boundary portion in an information recording layer may affect a tracking servo for recording the information onto said one information recording layer.

Information recording apparatus

An optical pickup apparatus includes a photodetector for receiving a diffracted light reflected from the recording medium; and a tilt detector for detecting a tilt amount of the recording medium on the basis of a light intensity within an interference region of a 0th-order diffraction light and at least one diffraction light other than the 0th-order diffraction light of the reflected light received by the photodetector.

Optical pickup apparatus and tilt amount detecting method

A recording method of a multilayer recording medium includes a first initializing step of initializing a lower recording layer based on a first initializing condition and a second initializing step of initializing an upper recording layer on the basis of a second initializing condition different from the first initializing condition. The second initializing condition is determined so that a transmittance of the recording layer after execution of the second initializing step is approximately equal to a transmittance of the recording layer after a predetermined data signal is recorded on an upper recording layer.

Multilayer optical recording medium and recording method and apparatus for the same

An information recording and reproducing apparatus for optically recording/reproducing information to/from a two-layer optical disk comprises a cylindrical lens, which gives astigmatism to a reflected light from a target information recording layer, two caustic curve positions are arranged in the front and in the rear of the optical detector, and an unnecessary reflected light from an another information recording layer has two caustic curve positions arranged in the rear of the optical detector. In this condition, assuming an astigmatism direction of the cylindrical lens is inclined at 45 degree angle to a track direction, a projected image of the target information recording layer is inclined at 90 degree angle to an another projected image of the another information recording layer in a light receiving surface of the optical detector.

Information recording and reproducing apparatus

An aberration correction device for correcting aberration produced in a light beam, which includes: a first electrode layer and a second electrode layer being opposed to each other; and a liquid crystal disposed between the first electrode layer and the second electrode layer for producing a change in phase in a light beam passing therethrough in accordance with voltages applied to the first electrode layer and the second electrode layer. The first electrode layer is divided into a plurality of phase adjustment portions which are electrically isolated each other. Each of the plurality of phase adjustment portions includes a pair of electrodes arranged in such a form that produces an electric field distribution for correcting the aberration by applying predetermined voltages thereto.

Aberration correction apparatus and method

The collision preventing device is used for an optical pickup device for recording or reproducing information to or from an optical information recording medium. The collision preventing device has a shock absorbing layer to prevent a contact of an objective lens and a surface of the recording medium. The shock absorbing layer is laminated on the portion extending from the circumferential edge of the effective-diameter area of the objective lens to the outside edge or to the outside of the objective lens and has a thickness in such a manner that the shock absorbing layer comes in contact with the surface of the recording medium prior to the effective-diameter area, when the objective lens comes close to the surface of the recording medium.

Objective lens collision preventing device and method for manufacturing the same

An aberration correcting element includes a first electrode layer including a plurality of electrode portions; a second electrode layer opposed to the first electrode layer; and a liquid crystal sandwiched between the first and second electrode layers for producing a phase change corresponding to voltages applied to the first and second electrode layers in a light beam passing therethrough. The first electrode layer includes a plurality of position markers.

Aberration correcting element and assembly

The present invention relates to an optical multi-layer information recording medium for recording information therein and/or retrieving information therefrom upon radiation of a convergent beam of light. The recording medium includes at least two pairs of recording layer and light-transmissive layer stacked one after another. A first recording layer proximal to a beam radiation side and a second recording layer distal from the beam radiation side are made from a material that satisfies a function including the following parameters; transmissivity and absorptance of the first recording layer, absorptance of the second recording layer, a numerical aperture on the first recording layer, a numerical aperture of the second recording layer, and transmissivity of between the first and second recording layers. Even if the numerical apertures change with spherical aberration compensation made to respective recording layers, a power density of a light spot does not change. Thus, recordation can be performed with consistent recording characteristics.

Optical multi-layer information recordating medium

The present invention relates to a cartridge and a method that can sweep away dust or the like from a recordation medium housed in the cartridge in a simple way without adversely influencing recording and replaying of the recordation medium. The cartridge includes a shutter opposed to a surface of the recordation medium, a cleaner member, a support for supporting the cleaner member, and a sweeping mechanism actuated upon opening and closing movements of the shutter. The support pivots in a plane substantially in parallel to the surface of the recordation medium when the sweeping mechanism is actuated. When the sweeping mechanism moves forwards, the cleaner member moves without contacting the recordation medium surface. When the sweeping mechanism moves backwards, the cleaner member moves in contact with the recordation medium surface to clean the recordation medium surface.

Cartridge and method of cleaning recordation medium surface

An optical pickup system includes a light source, an objective lens, a beam splitter for splitting light received from the light source and reflected light from an optical disc, a detector for receiving the reflected light, a liquid crystal panel for providing passing light with a phase difference in accordance with a control signal and a control means for providing the control signal to the liquid crystal panel to eliminate an influence of birefringence of the optical disc.

Optical pickup system

A polarization hologram lens includes: a first portion, positioned at a center of the hologram lens, on which no grating pattern is formed; and a second portion, positioned at an outer circumferential area of the first portion, on which grating patterns are formed, wherein the grating patterns do not diffract a light beam of a first polarization direction, and wherein the grating patterns diffract a light beam of a second polarization direction perpendicular to the first polarization direction to produce a diverging diffracted light or a converging diffracted light.

Polarization hologram lens, optical pickup, information reproduction apparatus and information recording apparatus

In an optical pickup, the focal position of the reflected light from the information bearing surface where information is to be reproduced and that of the reflected light from other information bearing surfaces are adjusted by an optical device such that the two reflected light components are separated optically.

Growing community of inventors

Tsurugashima, Japan

Yoshitsugu Araki