Panasonic Corporation

Matsushita Electric Industrial Co., Ltd.

Eishin Mori

Joji Anzai

Hideki Aikoh

Yoshiaki Komma

Fumitomo Yamasaki

Akihiro Arai

Kousei Sano

Takayuki Nagata

Hideki Hayashi

Naoya Hotta

Hidenori Wada

Keiichi Matsuzaki

Tatsuo Ito

Jouji Anzai

Makoto Takashima

Kenichi Shinotani

An object of the invention is to provide an optical disc device, an optical head, and an information processing device that enable to advantageously record or reproduce information with respect to an information recording medium having three or more information recording surfaces with light transmissive layers of different thicknesses from each other. Assuming that an aberration amount of third-order coma aberration resulting from tilting a multilayer optical disc () by a unit angle is CMD0 (unit: m&#x3bb;/deg), an aberration amount of third-order coma aberration resulting from tilting an objective lens () by a unit angle is CML0 (unit: m&#x3bb;/deg), a tilt angle of the multilayer optical disc () is &#x3b8;, a coefficient is k0, and a tilt angle of the objective lens () by an objective lens actuator () is &#x3b1;in converging laser light on an information recording surface having a largest light transmissive layer thickness out of the information recording surfaces of the multilayer optical disc (), the objective lens actuator () tilts the objective lens () in such a manner that the tilt angle &#x3b1;of the objective lens () satisfies the following mathematical expression:&#x3b1;0=&#x3b8;&#xd7;0&#xd7;0/0, where 0.5&#x3c;k0&#x3c;0.9.

Optical disc device, optical head, and information processing device

An object of the invention is to provide an optical element for use in an optical information recording and reproducing device or a like device for recording or reproducing information with respect to an information recording medium using laser light, wherein the optical element is a resin optical element capable of suppressing lowering in transmittance due to deterioration by irradiation of light having a high energy density, and maintaining a high transmittance for a long time. To realize the above object, used is an optical element made of a silicon resin cured material obtained by subjecting a silicon resin composition containing a silsesquioxane compound to a curing treatment.

Optical head, optical information recording and reproducing device, and optical information system device

To provide an optical head to produce good servo and read signals by reducing the influence of interference by light reflected from a non-read layer of a multilayer optical disc. The head includes: a first optical system for converging light from a light source on a first or second storage layer; a second optical system for receiving and transmitting light reflected from the first layer and stray light reflected from the second layer when the light is converged on the first layer; a photodetector; and a calculator. The photosensitive areas of the photodetector output signals representing intensities of the light incident there through the second system. The reflected and stray light incident on the second system interfere with each other, and the first and second groups of areas are arranged so as to be equally affected by a variation in intensity caused by the interference. The calculator calculates the difference between sum of a first group of signals supplied from a first group of areas and that of a second group of signals supplied from a second group of areas, thereby generating a focus error signal.

Optical head

An object of the invention is to suppress an influence of a wavefront aberration which is generated at the time of correcting a third-order spherical aberration, and realize satisfactory information recording and/or reproducing. A collimator lenscorrects a third-order spherical aberration which is generated depending on the thickness of a light transmissive layer from a surface of a first optical information recording medium, corresponding to an optimal substrate thickness of a first objective lens, to an intended information recording surface, assuming that the light transmissive layer thickness of the first optical information recording mediumwhich minimizes a residual third-order spherical aberration at the time of incidence of parallel light into the first objective lensis defined as the optimal substrate thickness of the first objective lens. The optimal substrate thickness of the first objective lensis defined in such a manner that a variation of a wavefront aberration which is generated on the information recording surface of the first optical information recording mediumfarthest from the first objective lensat the time of correcting the third-order spherical aberration, and a variation of a wavefront aberration which is generated on the information recording surface of the first optical information recording mediumclosest to the first objective lensat the time of correcting the third-order spherical aberration are set equal to each other.

Optical head device, and recording and/or reproducing device

An optical head device includes a first light source and a second light source respectively emitting a first light beam and a second light beam, a luminous flux separating section selectively separating the first and second light beams for which the same optical path is used, to first and second optical paths, respectively, and a first objective lens converging the first light beam that has been separated to the first optical path on the first optical information recording medium. Further, the optical head device includes a second objective lens made of resin and converging the second light beam separated to the second optical path on the second optical information recording medium, and a first filtering section formed on a beam exit face of the second objective lens and reducing the transmittance of the first light beam to be lower than transmittance of the second light beam.

Optical head device and recording/reproduction device

An optical head that is restrained from becoming larger, even if it is used for an optical-information recording medium that includes a plurality of information recording layers. In this optical head, a collimating lens is formed by a concave lens disposed on the side of a light source and a convex lens disposed on the side of an objective lens. A collimating-lens actuator moves the convex lens in a direction where a spherical aberration is cancelled which is generated according to the thickness of a light transmission layer up to an information recording layer of the optical-information recording medium. An aperture stop is provided on the side of the collimating lens with respect to the objective lens, and the aperture stop is located near the focal position of the convex lens on the side of the objective lens.

Optical head, and information recording-and-regeneration apparatus

An optical controller includes a light source for emitting light, an object lens for condensing light emitted from the light source, a light detection unit for receiving light reflected on an optical information recording medium and outputting a signal corresponding to the amount of the light, and a laser control unit for controlling the amount of the light emitted from the light source to the information recording surface on which information is to be recorded or reproduced, based on the recording state of an information recording surface disposed closer to the object lens than an information recording surface on which the information is to be recorded or reproduced.

Optical control device, optical information recording/reproducing device, optical information recording medium and optical head control method

An optical head includes a hologram which extracts, from a luminous flux of reflected light from an optical disk, at least a first luminous flux branch which does not include the optical axis of the luminous flux; and a photodetector which receives the reflected light from the optical disk and produces signal output, wherein the photodetector has light-receiving areas which receive the first luminous flux branch of reflected light from an optical information recording medium layer targeted for recording or playback out of the plurality of optical information recording medium layers of the optical disk, the light-receiving areas are placed in such a way that the signal output resulting from a light spot formed by the first luminous flux branch of the reflected light from the optical information recording medium layer targeted for recording or playback is practically the same between the first and second photodetection areas, and a boundary line of the light-receiving areas is located in such a position as not to include light spots formed by luminous fluxes of reflected light from the optical information recording medium layers other than the optical information recording medium layer targeted for recording or playback.

Optical head, control method for optical head, and optical information processing apparatus

An optical head device is provided with a semiconductor laser, an aberration correcting element for transmitting a beam from the semiconductor laser, a light guiding portion for introducing the beam from the semiconductor laser to the aberration correcting element, and an objective lens for focusing the beam having passed through the aberration correcting element on an optical disc. The aberration correcting element corrects a longitudinal chromatic aberration occurring in the objective lens and a longitudinal chromatic aberration occurring in the light guiding portion excluding the objective lens and the aberration correcting element based on a longitudinal chromatic aberration occurring in the aberration correcting element when the semiconductor laser emits a beam having a wavelength different by a specified wavelength difference. Therefore, an optical head device, an aberration correction method and an optical information processing apparatus can be provided which can suppress a longitudinal chromatic aberration occurring in the entire optical system from a light source to an objective lens.

Optical head device, aberration correction method and optical information processing apparatus

Fifth order spherical aberration in addition to third order spherical aberration for an optical information recording medium of which thickness of a light transmission layer changes greatly is corrected. An objective lens collects a laser beam emitted from a semiconductor laser on an optical information recording medium. A spherical aberration correcting portion corrects spherical aberration generated according to a thickness of the light transmission layer of the optical information recording medium, in which the spherical aberration correcting portion includes a collimator lens, a lens holder and a stepping motor for correcting the third order spherical aberration and a liquid crystal element and an applied voltage control portion for correcting the fifth order spherical aberration.

Optical head and optical information recorder/reproducer

A lens surface of a collimating lens closer to a light source is in contact with a retracted surface at one end surface of a barrel. On a projecting surface at an outer side of the one end surface of the barrel, grooves are formed at a plurality of positions symmetric with respect to an optical axis. An adhesive deposited in the grooves is applied to an outer circumferential surface of the collimating lens to fix the collimating lens in the barrel. Since the grooves are formed to be shallower than the retracted surface, the adhesive does not intrude onto the retracted surface. The barrel is pressed against a wall surface formed in an inner circumferential surface of a barrel holder main portion and having a V-shaped cross section by a leaf spring, thereby being held at a specified position in the barrel holder main portion. An amount of change in distance from a reference surface to a held position of the collimating lens per unit temperature is set to conform to a sum of an amount of change in movement of the light source from the reference position per unit temperature and an amount of change of back focus of the collimating lens per unit temperature.

Beam shaping optical device, optical head, and optical information medium drive unit

An optical pick-up capable of reproducing information excellently on both CD and DVD, which are significantly different in terms of three kinds of factors, a base material thickness, a wavelength of a light source, and NA, and detecting TE signals by three kinds of methods, that is, the phase difference method, the PP method, and the 3-beam method, which are necessary to record and reproduce information. The optical pick-up is formed by integrating laser light sources having two kinds of wavelengths (&#x3bb;) for detecting TE signals; photodetectors, and hologram for generating the diffracted light for detecting signals. The distance dbetween the center of the photo detecting portion PDand the light emitting spot of the first semiconductor laser light source and a distance dbetween the center of the photo detecting portion PDand the light emitting spot of the second semiconductor laser light source substantially satisfy the following relationship:&#x3bb;

Optical pick-up, optical disk apparatus and information processing apparatus

Disclosed is an optical head, which comprises a semiconductor laser, a collimator lens for converting a beam emitted from the semiconductor laser light into parallel beam, a lens frame holding the collimator lens, a beam shaping prism for shaping the parallel beam passing through the collimator lens from an elliptic section into a circular section, an objective lens for converging the parallel beam passing through the beam shaping device on an optical recording medium formed with a track, and a photodetector for detecting a reflected light or transmitted light from an optical disk. The collimator lens is adhesively fixed to the lens frame at two positions opposed to one another along a radial direction corresponding to the minor axis direction of the cross section of the incoming parallel beam into the beam shaping prism. The optical head can suppress the displacement of detected-light spots in an photodetector caused by the displacement of an optical axis due to change in ambient temperature.

Optical head and optical recording medium drive

A lens support mechanism including a semiconductor laserfor emitting a laser beam, an optical head enclosureto which the semiconductor Laseris fixed and located, a collimator lensdisposed coaxially with the laser beam emitted from the semiconductor laser, a resin cylinderformed in a cylindrical shape so as to fix and locate the collimator lensto the inner surface thereof and a cylindrical memberfitted to the resin cylinderon a side of the collimator lensopposite to the semiconductor laserand formed so as to be fixed to the optical head enclosure. The cylindrical memberhas almost the same linear expansion coefficient as that of the optical head enclosure

Growing community of inventors

Kyoto, Japan

Eishin Mori