Matsushita Electric Industrial Co., Ltd.

Panasonic Corporation

Sadao Mizuno

Yoshiaki Komma

Hideki Hayashi

Hidenori Wada

Seiji Nishino

Noboru Ito

Hiroaki Yamamoto

Shinichi Tanaka

Keiichi Matsuzaki

Kousei Sano

Daisuke Ogata

Shin-ichi Kadowaki

Tomotada Kamei

Jouji Anzai

Kenichiro Urairi

Kenichi Nishiuchi

Isao Satoh

Yasuhiro Tanaka

Shinji Uchida

Noboru Yamada

Fumitomo Yamasaki

Tsuguhiro Korenaga

Katsuhiko Hayashi

Hideki Aikoh

Tetsuo Saimi

Yasuhiro Gotoh

Akihiro Yasuda

Takashi Ishida

Seiji Nishiwaki

Makoto Kato

Michihiro Yamagata

Ken'ichi Kasazumi

Teruhiro Shiono

Taketoshi Yonezawa

Tatsuo Ito

Yoshinao Taketomi

Shunji O'Hara

Naoya Hotta

Takaaki Tomita

Noboru Itoh

Seji Nishino

Atsuo Kikuchi

An optical pickup, an inclination angle detection method, an optical information device, and an information processing device capable of reliably and accurately detecting a relative inclination angle between an end face of a solid immersion lens and a surface of an optical recording medium are provided. A convergence position modifying unit modifies convergence states of a first beam and a second beam according to layers of an optical recording medium, a first optical detector includes a first light receiving section which receives the converged first beam and a second light receiving section which receives the converged second beam, and the first optical detector detects a relative inclination angle between an end face of a solid immersion lens and a surface of the optical recording medium based on a difference in quantities of received light between the first light receiving section and the second light receiving section.

Optical pickup, inclination angle detection method, optical information device and information processing device

Provides an objective lens, an optical head and an optical disc apparatus (drive) capable of compensating for various types of aberrations including wavelength changes for a plurality of types of optical discs including high density optical discs, DVDs and CDs with a good wavelength dispersion compensation ability and thus capable of providing good recording or reproduction characteristics. The objective lens according to the present invention includes a first lens and a second lens substantially in close contact with each other such that optical axes thereof match each other, and acts as a convex lens as a whole. Each lens includes a central portion including the optical axis and a peripheral portion located in a periphery of the central portion. The central portion of the first lens acts as a convex lens; and the central portion of the second lens acts as a concave lens. Where the refractive index of the first lens at d line (wavelength: 587.56 nm) is nd1, the Abbe constant of the first lens represented using the refractive indices at d line, F line (wavelength: 486.13 nm) and C line (wavelength: 656.27 nm) is &#x3bd;d1, the refractive index of the second lens at d line is nd2, and the Abbe constant of the second lens represented using the refractive indices at d line, F line and C line is &#x3bd;d2, the objective lens fulfills nd1&#x3e;nd2 and &#x3bd;d1&#x3e;&#x3bd;d2.

Objective lens, optical head and optical disc device

An optical head for recording or reproducing a signal on or from an optical recording medium including a light source, an objective lens for condensing light emitted from the light source to the optical recording medium, and a light-separating device arranged between the light source and the objective lens in order to separate the light reflected from the optical recording medium from the light emitted from the light source. The light-separating device includes a first glass, a multilayer film formed on the first glass, and an adhesive layer arranged on the multilayer film in order to bond a second glass onto the multilayer film. The majority of the light emitted from the light source enters into the light-separating device through the first glass and is reflected by the multilayer film.

Optical head for optical recorder/reproducer

An optical pickup head is provided with a light source, a diffracting means for creating a plurality of diffracted beams, a converging means for focusing the diffracted beams onto an optical storage medium, a beam branching means for branching the plurality of beams reflected by the optical storage medium, and an optical detecting means for outputting a signal corresponding to the amount of light of the received beams. The optical detecting means has main beam light receiving portions and sub-beam light receiving portions. The amount of light of the first or higher order diffracted beams when they are substantially focused on and reflected by a focus plane of the plurality of information recording planes is equal to or greater than the amount of light of the zero order diffracted beam when it is reflected without focusing by a non-focus plane other then the focus plane of the plurality of information recording planes. The invention provides an optical pickup head where offset is not generated in the TE signals even during tracking with the objective lens when a two-layered disk is used.

Optical pickup head and information recording/reproducing device

A compact and inexpensive optical head that enables stable compatible playback and compatible recording with optical discs of different kinds with the use of a single objective lens is achieved. The order of diffracted light at which the diffraction efficiency by a diffraction element forming the objective lens becomes the maximum is set to the third order for blue light, the second order for red light, and the second order for infrared light in the inner peripheral portion of the diffraction element, and to the sixth order for blue light, the fourth order for red light, and the third order for infrared light to limit the aperture for infrared light in the intermediate peripheral portion. In the outer peripheral portion, the aperture for red light is limited by setting the order to an integer other than multiples of 3 for blue light.

Optical head and optical disc device

A diffraction grating is constituted such that directions of diffraction are disposed asymmetrically with respect to the optical axis, by causing light subjected to aperture restriction to have a difference of one half wavelength in the optical path length by making use of the fact that the difference in the optical path length experienced by the light passing through a diffraction element varies depending on the wavelength. With this constitution of the diffraction grating, aperture restriction is applied to both the light focused on an optical disk and the light reflected from the optical disk, thereby achieving an optical pickup that is capable of recording/reproducing information on/from optical disks of different types by using a single objective lens. The optical pickup prevents unnecessary light from entering a photodetector and enables the production of diffraction elements at a low cost.

Optical pickup, optical disk device, computer and optical disk recorder

Provides a coupling lens which, when used in combination with an objective lens for a plurality of types of optical discs such as a high density disc, DVD, CD or the like, is capable of compensating for various types of aberrations including those caused by wavelength changes and thus providing good recording or reproduction characteristics with a good wavelength dispersion compensation ability; and an optical head and an optical disc apparatus (drive). A coupling lens is incorporated into an optical head for collecting laser light emitted from a plurality of light sources and having different wavelengths on an information recording face of different types of optical information recording mediums respectively. The coupling lens comprises a first lens and a second lens which are substantially in close contact with each other such that optical axes thereof match each other and designed such that the laser light having different wavelengths are refracted by the close contact face. The coupling lens is afocal for the shortest wavelength among the different wavelengths of the laser light.

Coupling lens, optical head and optical disc device

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

Providing an objective lens with a large numerical aperture (NA), the present invention records or plays conventional optical disks such as CDs and DVDs using an optical head capable of recording or reproducing high-density optical disks. An optical element () is provided between a first and second laser light source and an objective lens () for the purpose of converting a wave front of a second optical beam. Furthermore, the optical element () and the objective lens () are fixed to move as a single piece.

Optical element and optical head device using it, and optical information device using this optical head device, and computer, optical disk player, car navigation system, optical disk recorder and optical disk server using this optical information device

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

An optical head which is capable of realizing a stable tracking control, even if the rotational center of an information recording medium is not located on the extension line of the transfer directions of a light-concentrating element, includes: a semiconductor laser which emits a beam of light; an objective lens which concentrates the beam of light on an optical disk; a transfer mechanism which transfers the objective lens between the outermost circumference and the innermost circumference of the recording area of the optical disk along the optical disk; and a photo-detector which detects a beam of light that returns from the optical disk. The photo-detector includes a plurality of areas which are divided by a division line. The division line is set parallel to the tangential directions of the track in a predetermined position on the transfer line of the objective lens between the outermost circumference and the innermost circumference of the recording area, and the plurality of areas are divided, by a lateral division line which intersects the division line, into a first area on which a beam of light that mainly includes a tracking component is incident and a second area on which a beam of light that does not include the tracking component is incident.

Optical head and optical information apparatus for recording or reproducing information on an information recording medium

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 objective lens for converging a light beam emitted from a first light source on a recording surface () of a first optical information recording medium covered with a transparent substrate () and converging a light beam emitted from a second light source on a recording surface () of a second optical information recording medium covered with a transparent substrate () having a thickness greater than the transparent substrate (). On an incident plane for the light beam, there are formed a center region (A), an intermediate region (A) surrounding the center region (A), and a peripheral region (A) surrounding the intermediate region (A). A diffraction grating () is provided on the lens surface of the intermediate region (A). Between the intermediate region (A) and the center region (A), and also between the intermediate region (A) and the peripheral region (A), stepped portions () are provided for causing an advance or a delay of a phase of a light beam passing through the intermediate region (A) with respect to the phases of the light beams passing through the center region (A) and the peripheral region (A). The stepped portions () are formed so that a value of a tertiary spherical aberration on the recording surface () of the second optical information recording medium becomes a value that makes a jitter value of a reproduction signal from the second optical information recording medium not more than 15%.

Objective lens, optical head apparatus, optical information recording/reproducing apparatus

Growing community of inventors

Ibaraki, Japan

Sadao Mizuno