Abstract: Provided is an optical pickup apparatus using a reduced number of parts. An optical pickup apparatus (26) of the present invention includes: a laser unit (108) for emitting a laser beam complying with the BD standards; a laser unit (106) for emitting a laser beam complying with the DVD standards and a laser beam complying with the CD standards; and a PDIC (10B) for receiving and detecting the laser beams complying with the respective standards. Because the laser beam complying with the DVD standards and the laser beam complying with the BD standards are received by one photo detector provided in the PDIC (10B), the number of parts needed for the optical pickup apparatus (26) can be reduced, and the costs of the apparatus can be decreased.

Abstract: For use with a multi-layer optical disc, an optical pickup can eliminate a problem of causing a focus error signal and a tracking error signal to fluctuate due to interference of a signal light beam with a return light beam from another recording surface of a multi-layer optical disc during reproduction with an optical pickup that produces a tracking error signal and a focus error signal from a difference signal based on polarized reflected light.

Abstract: Stable performance of additional recording and erasing and rewriting operations is allowed regardless of a change in inclination of a guide layer separable optical disc. An optical pickup device includes an angle variable reflection mirror (an optical axis angle variable element) which changes directions of optical axes of first and second light beams when the first light beam for recording or reproduction and the second light beam for servo signal detection are emitted from laser diodes and incident upon the optical disc through an objective lens. When additional recording is performed on the optical disc, the optical axis angle of the angle variable reflection mirror is adjusted such that a tracking error signal detected from a record layer with the first light beam is reduced to almost zero while tracking control is being performed on a guide layer with the second light beam.

Abstract: An optical head includes a blue-violet laser light source for emitting a blue-violet laser beam, a mirror with a diffraction grating for transmitting and reflecting the blue-violet laser beam at a predetermined ratio, and a front monitor sensor for receiving transmitted light or reflected light from the mirror with a diffraction grating and creating an APC signal for controlling an output of the blue-violet laser light source. The mirror with a diffraction grating includes a first surface which the blue-violet laser beam enters, and a second surface facing the first surface. The first surface and the second surface are mutually parallel. A reflecting coat for transmitting and reflecting the blue-violet laser beam at a predetermined ratio is formed on the first surface, and a diffraction grating is formed on the second surface.

Abstract: A recording apparatus for performing information recording using formation of marks by focusing a first light with an objective lens at a given position in a recording layer included in an optical disc recording medium, includes: a rotation driving unit for rotating the optical disc recording medium; a focus servo control unit for condensing a second light which is different from the first light on a reflection film, and for controlling a position of the objective lens so that a focal position of the second light follows the reflection film; a recording position setting unit for setting an information recording position of the first light in a focus direction by changing the collimation of the first light; a surface wobbling amount estimating unit; and a surface wobbling estimation amount acquisition control unit for acquiring a surface wobbling estimation amount for each rotation angle within one revolution of the disc.

Abstract: A control device includes n optical pickups, n being an integer greater than one; a dividing unit configured to divide one block into n pieces of data, the one block being a predetermined amount of data; and a control unit configured to control the n optical pickups to record the n pieces of data obtained by the dividing unit on a predetermined recording medium.

Abstract: An optical pickup has a first optical system and a second optical system. The optical axis of the first optical system and the optical axis of the second optical system are inclined, for example, 45 degrees with respect to the reference plane, and are parallel to each other. A first objective lens and a second objective lens are arranged substantially side-by-side in a radial direction, and the center position of the second objective lens is slightly displaced from the reference plane in a tangential direction. The first optical system and the second optical system each have a flat-shaped beam splitter; this is used to produce astigmatism for acquiring a focus error signal by the astigmatic method.

Abstract: Disclosed is an optical disc device that is able to increase accuracy in reproducing information from an optical disc. The optical disc device 10 calculates a focus error signal SFE2 and a sum signal SS1 while reciprocating an objective lens 21 in a focus direction until a distance between a focal point FS and a focal point FM1 becomes close to the depth d of a target position PG at the time of a pull-in operation, and when a trigger signal ST1 generated on the basis of the sum signal SS1 is at low level, starts focus control on the basis of the focus error signal SFE2. Therefore, focus control can start in a state where the focus error signal SFE2 curves in an S shape with sufficient amplitude.

Abstract: According to the present invention, of all beams of light reflected from the optical disc, only light in a peripheral region excluding a push-pull region is used to generate a DPD signal. In this method of signal generation that optimizes internal light-receiving surface interconnections in a photodetector, the lens error signal required for the generation of a tracking error signal in the DPP scheme is amplified at a lower amplification factor. In addition, the light reflected from the multilayered optical disc will be divided into a plurality of regions and the divided beam of light will be focused at different positions on the photodetector. When the beam is focused upon a desired layer, stray light from recording layers other than those to be subjected to information reproduction will not enter the photodetector light-receiving surfaces used for servo signals.

Abstract: There is provided an optical disc drive, which includes a light source emitting a light beam, a beam dividing element that divides the light beam into main and sub-beams, an objective lens, an astigmatism producing unit that gives astigmatism to the main and sub-beams, a signal generation unit that has sensors for the beams and generates a focus error signal based on output signals of the sensors; and an optical element that has a function of adjusting intensity distribution of the main beam such that the main beam incident on the optical disc has a predetermined intensity distribution where a maximum intensity level is positioned at a predetermined height within a range of 70% of a pupil diameter, the predetermined height is not equal to an optical axis, and an intensity of the main beam decreases gradually from the predetermined height to a peripheral portion of the pupil.

Abstract: According to one embodiment, a pickup head includes a plurality of light sources, a first objective lens, second objective lens, a driving unit, a first control unit, a second control unit, light receiving units. The first objective lens focuses a first light beam at a first recording layer. The second objective lens focuses a second light beam at a second recording layer. The driving unit moves the first objective lens and the second objective lens in a first direction and a second direction. The first control unit corrects displacement from target track along the first direction. The second control unit controls a moving direction of a position of the second light spot in the second direction.

Abstract: Techniques are provided for controlling the reading of optical data from a master disk in a holographic replication system. Imperfections in the master disk or movement of the disk during a recording process may cause source beams to deviate from target data tracks. In some embodiments, a detector system is used to determine the focus and alignment of the source beams on the master disk, as well as the tilt and rotation of the disk with respect to the holographic replication system. The detector system may detect deviations in the intensity distribution of the reflections of the source beams and generate an error signal corresponding to focusing, tracking, tilt, and/or rotational errors. Servo-mechanical devices may actuate optical components to compensate for such errors.

Abstract: An optical pickup device includes: a first light source for emitting recording laser light; a second light source for emitting reproducing laser light having a wavelength different from a wavelength of the recording laser light; an objective lens for converging the recording laser light and the reproducing laser light. A quarter wavelength plate is disposed between the first light source and the second light source, and the objective lens. A wavelength-selective polarized beam splitter is disposed between the quarter wavelength plate, and the first light source and the second light source. The reproducing laser light alone out of the recording laser light and the reproducing laser light reflected on recording medium is guided to a photodetector.

Abstract: An optical recording medium driving apparatus includes an optical pickup which irradiates first and second laser lights from one object lens with respect to an optical recording medium having a bulk layer and a tilt detection surface; a focus control portion that performs the focus control relative to each predetermined position of the optical recording medium in regard to each of the first and second laser lights; a tracking control portion that controls the position of the object lens to perform the tracking control of the first and second laser lights relative to the optical recording medium; and a tilt control portion.

Abstract: The optical disc comprises a substrate layer and a data layer disposed on the substrate layer, the data layer having a mark/space data structure arranged in tracks which are arranged in groups being separated each by a land section. The tracks of the groups are each arranged as a spiral, and the start of a track of a consecutive group begins at a position corresponding with the end of a track of a preceding group. A group comprises advantageously an inner track, a center track and an outer track. The optical disc comprises in a preferred embodiment a nonlinear layer with a super-resolution structure and the track pitch between neighboring tracks within a group is below the diffraction limit of a corresponding pickup for reading of data. Further, a tracking method is described which does not rely on tracking offsets to detect the inner and outer tracks of a group.

Abstract: An optical recording medium including recording and reading layers and a servo layer increases the recording capacity thereof. In the optical recording medium including the plurality of recording and reading layers and the servo layer, the servo layer has a groove and a land that can be used to perform tracking control with a long-wavelength servo beam. Information is recorded on the recording and reading layers with a recording and reading beam having a wavelength shorter than the wavelength of the servo beam. Recording marks are formed on the recording and reading layers while both the groove and land are tracked.

Abstract: An optical drive device generates a first push-pull signal and a first sum signal based on a light receiving amount in two light receiving areas of which each width in a signal light tangent direction is smaller than a diameter of a spot of signal light, generates a first normalized push-pull signal by normalizing the first push-pull signal by using the first sum signal, and generates a tracking error signal based on the first normalized push-pull signal.

Abstract: A first laser source is arranged on a transmitting side of a polarizing beam splitter, while a second laser source is arranged on a reflecting side of the polarizing beam splitter. The splitting surface of the polarizing beam splitter has a film characteristic of substantially transmitting s-polarization component of the laser light having the first wavelength emitted by the first laser source and substantially reflecting s-polarization component of the laser light having the second wavelength emitted by the second laser source. A plate-like beam splitter serves to introduce laser light reflected off of a signal recording medium into an optical detector by directing the laser light away from the optical path in which the laser sources are located. The plate-like beam splitter includes a splitting surface which has a reflectance that is higher than its transmittance.

Abstract: A photodetector detecting reflected light components from an optical medium, the photodetector including a first detector divided into eight sections detecting the reflected light components and converting the light components into electrical signals, a first calculating portion calculating a first tracking error signal from the electrical signals by a differential push-pull method, a second calculating portion calculating a first focusing error signal by an astigmatism method and calculating a second tracking error signal by a differential phase detection method from the electrical signals converted by the first detector; a second detector divided into four sections detecting the reflected light components reflected by the optical recording medium to convert the light components into electrical signals; and a third calculating portion calculating a second focusing error signal by the astigmatism method and calculating a third tracking error signal by the differential phase detection method from the electrica

Abstract: An optical head that includes a laser light source, an optical system that applies 0-order diffracted light, +1-order diffracted light, and ?1-order diffracted light, which are produced from laser light emitted from the laser light source, onto a recording medium having a plurality of information recording layers, and a light-receiving device for detecting reflected light guided by the optical system. The light-receiving device includes a first light-receiving section for detecting reflected light of the 0-order diffracted light, two second light-receiving sections for detecting reflected light of the +1-order diffracted light and reflected light of the ?1-order diffracted light, and a third light-receiving section provided near at least one of the second light-receiving sections to receive stray light reflected from one or more information recording layers other than a target information recording layer to be accessed.

Abstract: An optical pickup equipped with a laser light source which emits light beams of at least three wavelengths for recording/reproducing a plurality of information recording media detects light quantities of the light beams of three wavelengths using one light intensity monitor element. More specifically, one light intensity monitor element is arranged between a first laser light source and a second laser light source, light beams of wavelength ?1 and wavelength ?2 emitted from the first laser light source are made to proceed substantially straightforward, the optical path of the light beam of wavelength ?3 emitted from the second laser light source is changed to a diagonal one so as to cause the light beam to be introduced diagonally to the light receiving surface of the one light intensity monitor element.

Abstract: In a diffractive element, its grating pattern is so configured that a diffraction angle of a diffracted light beam of a light source that is subject to the first-order diffraction in a diffraction area is matched with an angle of a light beam passing through the diffractive area emitted from a light source and a light source position is matched with a light originating point of the light source that emits a light beam to be transmitted, and the center of light intensity distribution is matched with that of the light source passing through the diffractive element by inclining an optical axis of the light source. A position of the diffractive element is adjusted based on an electric current value generated when a reflected return path light beam of the light source is diffracted by the diffractive element and enters the light source.

Abstract: An optical head includes a blue-violet laser light source for emitting a blue-violet laser beam, a mirror with a diffraction grating for transmitting and reflecting the blue-violet laser beam at a predetermined ratio, and a front monitor sensor for receiving transmitted light or reflected light from the mirror with a diffraction grating and creating an APC signal for controlling an output of the blue-violet laser light source. The mirror with a diffraction grating includes a first surface which the blue-violet laser beam enters, and a second surface facing the first surface. The first surface and the second surface are mutually parallel. A reflecting coat for transmitting and reflecting the blue-violet laser beam at a predetermined ratio is formed on the first surface, and a diffraction grating is formed on the second surface.

Abstract: A spherical aberration correction mechanism 30 includes a lens holder 35 that holds a collimator lens 16, a main shaft 36a that supports the lens holder 35 in a linearly movable manner, a lead screw 34 supported in a rotatable manner and provided with a screw thread formed of a first slope and a second slope each in a spiral shape on an outer circumference thereof, and a stepping motor 13 that rotates the lead screw 34. The lens holder 35 includes a rack portion 41 disposed between the main shaft 36a and the lead screw 34 and having a slope that abuts on the first slope and first and second stoppers 46a and 46b that regulate a relative position of the rack portion 41 with respect to the lead screw 34 so that the rack portion 41 does not abut on the second slope.

Abstract: An optical disc recording and playback apparatus includes an optical pickup performing an operation for recording and playing back signal information into and from an optical disc; an optical element allowing a light beam irradiated onto an optical disc by the optical pickup to be split into a main beam and sub-beams on both sides of the main beam and supplying the beams to the optical disc; an optical detector detecting return light from the optical disc; and a computation circuit detecting a track control error signal by a phase difference method and a differential push-pull method by using the detection signal from the optical detector and also detecting a wobble signal.

Abstract: An optical disk apparatus appropriately adjusts the optical paths of a reference light beam and information light beam in an optical path forming section of an optical pickup, condenses the reference light beam and information light beam using an objective lens, and performs position control of the objective lens in the focusing and tracking directions so as to focus the reference light beam onto a reference track in a target mark layer, thereby focusing the focal point of the information light beam condensed by the objective lens onto a target track TG in the target mark layer.

Abstract: An optical disk discriminating method and an optical disk device which can detect reflected rays for making discrimination among kinds of optical disks with high accuracies. By switching a plurality of lasers and moving a spherical aberration corrector while moving an objective lens to cause it to approach or keep away from an optical disk, rays reflected light from the optical disk can be detected with high accuracies. Discrimination among the kinds of a plurality of optical disks can be made on the basis of signals generated from the detected reflected rays. This ensures that the kind of an optical disk can be determined through one operation of sweeping.

Abstract: An optical pickup includes: a first emitting unit to emit an optical beam of a first wavelength; a second emitting unit to emit an optical beam of a second wavelength; a third emitting unit to emit an optical beam of a third wavelength; an object lens to condense optical beams emitted from the first through third emitting units onto a signal recording face of an optical disc; and a diffraction unit provided on one face of an optical element or the object lens positioned on the optical path of the optical beams of the first through third wavelengths; wherein the diffraction unit includes a generally circular first diffraction region provided on the innermost perimeter, a ring zone shaped second diffraction region provided on the outer side of the first diffraction region, and a ring zone shaped third diffraction region provided on the outer side of the second diffraction region.

Abstract: Provided is a light-spot-position control apparatus including: a first-light-source; a second-light-source; a beam-splitter splitting a beam of the second-light-source into m beams; an optical-system allowing a first-beam of the first-light-source and the m beams to irradiate a disk-shaped recording-medium, where grooves and lands are alternately formed with an equal radial width to form the grooves in spiral/concentric shape through common-objective-lens, the optical-system allowing the three beams to irradiate the recording-medium so that an interval of m beam-spots is 1/m of track pitch; a tracking-control-mechanism tracking-controlling the beam by changing a relationship between the optical-axis and the recording-medium; a light-receiving unit individually receiving the m beams; an error-signal generator generating error-signals representing radial-position-errors of the spot-positions of the m beams with respect to the tracks based on received signals; an error-signal selector selecting at least one erro

Abstract: An objective lens includes a diffraction structure for distributing much of a quantity of an incident light beam into two diffracted lights having different diffraction orders from each other, wherein recording or reproduction of information on an optical disk is performed by converging the diffracted light having a longer focal length of the two diffracted lights onto an information recording surface through a protective layer of the optical disk, and a distance from the objective lens to a surface of the protective layer along an optical axis is longer than a distance between focuses of the two diffracted lights along the optical axis when the diffracted light having the longer focal length is converged onto the information recording surface of the optical disk.

Abstract: A method for adjusting a tilt of an optical pick-up head includes the steps of: moving the optical pick-up head to a first location and focusing on; obtaining a first focus control power and a first optimum tilt angle at the first location; moving the optical pick-up head to a second location and focusing on; obtaining a second focus control power and a second optimum tilt angle at the second location; calculating an optical sensitivity according to the first and second optimum tilt angles, and the first and second focus control powers; and when the head is moved to a specific location where the tilt of the head is to be adjusted, storing a focus control power corresponding to the specific location, and calculating a tilt angle corresponding to the specific location according to the focus control power and the optical sensitivity so that the tilt of the optical pick-up head can be appropriately adjusted.

Abstract: An information recording medium of the present invention is an information recording medium characterized by and including a substrate; and a recording unit capable of recording three-dimensionally a recording pit on the substrate; in which the recording unit has n number of recording layers (n is an integer equal to or larger than 4) and a plurality of intermediate layers laminated with the recording layers one on another; the recording is performed by the condensed recording light using a two photon absorption phenomenon; each of the plurality of intermediate layers is substantially transparent at a wavelength ?1 of the recording light and at a wavelength ?2 of the reproduction light, respectively; the light intensity of the recording light incident into the recording layer nearest to the substrate is more than 0.707 fold as much as the light intensity of the recording light incident into the recording layer farthest from the substrate.

Abstract: An optical disk apparatus for writing signals on a recording medium by irradiating the recording medium with a laser beam modulated based on the signals includes a first converting unit for converting a first reflected laser beam component from the recording medium into electrical signals; a second converting unit for converting a second reflected laser beam component into electrical signals; a first sample-and-hold unit for sampling and holding the electrical signals from the first converting unit; a second sample-and-hold unit for sampling and holding the electrical signals from the second converting unit; and transmitting devices for transmitting the held signals from the first and the second sample-and-hold units. The sampled signals are averaged, and the averaged signal is held in each of the first and the second sample-and-hold units during signal writing.

Abstract: An optical pickup includes a light source configured to emit light, a beam splitter configured to transmit or reflect light, an object lens configured to condense the light transmitted by the beam splitter onto an optical storage, and a diffraction grating having a first grating pattern and a second grating pattern. The first grating pattern is configured to diffract and divide the light reflected by the optical storage into a main beam and two sub beams. The second grating pattern is configured to diffract the light along a different diffracting direction than the first grating pattern. A condensing lens is configured to generate astigmatism to the light diffracted by the first grating pattern, and a light sensor is configured to receive the light via the condensing lens and detect a tracking error signal.

Abstract: Provided is an optical pickup device capable of stabilizing a tracking signal and a focusing signal and of preventing quality deterioration of a data signal by eliminating a multi-layer crosstalk. Of reflected lights from a multi-layer disc, a reflected light from a target layer is split into two by a light flux splitting optical system so that the reflected light is spread out toward two directions with respect to a central line, and then the split lights are condensed. In this case, a reflected light from another layer does not reach a condensing position of the reflected light from the target layer, and only the reflected light from the target layer can be detected by a detector. Accordingly, a crosstalk from the another layer is eliminated.

Abstract: Multi-level recording is quite effective for attaining a larger capacity and a higher transfer rate in the case of an optical disk; however, with conventional technologies, a SIGNAL-TO-NOISE RATIO of a signal deteriorates along with an increase in a multi-level degree, creating a factor for limitations to the multi-level degree. In order to solve problems, when optical information is recorded by use of a standing wave occurring due to interference between two light beams, at least one of the two light beams is modulated in multi-stages. Further, at the time of regeneration, a regeneration reference beam is caused to interfere with respective polarization components of a regeneration beam, the polarization components being orthogonal to each other, thereby concurrently generating not less than three interference beams differing in interference phase from each other before being detected.

Abstract: In order to record an interference fringe pattern in a recording layer of a medium, a plurality of laser beams are caused to interfere so as to form interference fringes in the recording layer; and during a time period over which the plurality of laser beams are caused to interfere, the following steps are continuously performed: (1) producing a signal varying according to a shift of a specific position in the recording layer; and (2) shifting a fringe-forming position in the recording layer by changing a phase of at least one of the laser beams or moving the recording layer based upon the signal produced in the step (1).

Abstract: Disclosed herein are aspects of optical tape technology, tape manufacturing, and tape usage. Methods and systems of tape technology disclose optical tape media including: configurations, formulations, markings, and structure; optical tape manufacturing methods, systems, and apparatus methods and systems including: curing processes, coating methods, embossing, drums, testing, tracking alignment stamper strip; optical tape methods and systems including: pick up head adapted for the disclosed optical tape; and optical tape uses including optical storage media devices for multimedia applications.

Abstract: 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.

Abstract: An optical pickup for irradiating an information recording medium, such as a DVD, with a laser beam when an information signal is recorded or reproduced, and information equipment provided with the optical pickup.

Abstract: The optical pickup device according to the present invention includes: a light source which emits a first light at a first wavelength, a second light at a second wavelength and a third light at a third wavelength; an optical path combining unit which combines vectors of the first, second and third light emitted by the light source, and matches optical axes of the first light and the third light; a light collection unit which condenses the light from the optical path combining unit into the optical information storage medium; a diffraction element which diffracts reflected light from the optical information storage medium; a first photo detector, a second photo detector and a third photo detector which receives the diffracted light from the first diffraction element; and a prevention unit formed between the first diffraction element and the first photo detector, the second photo detector and the third photo detector, and which prevents irradiation of + first-order diffracted light diffracted by the first diffr

Abstract: An optical pickup apparatus comprising at least: a diffraction grating configured to split first wavelength light into at least a first main beam and first sub-beam, and to split second wavelength light into at least a second main beam and second sub-beam, the diffraction grating including a diffraction surface portion corresponding to the second wavelength light; and a photodetector including a first main light-receiving unit configured to be applied with the first main beam, a first sub-light-receiving unit configured to be applied with the first sub-beam, a second main light-receiving unit configured to be applied with the second main beam, and a second sub-light-receiving unit configured to be applied with the second sub-beam, a distance between the first main light-receiving unit and first sub-light-receiving unit being changed relative to a standardized distance between the first main light-receiving unit and first sub-light-receiving unit.

Abstract: In an optical head apparatus and an optical disc apparatus which can reduce influence of interlayer stray light on a differential push-pull signal without making the configuration complicated, Uy=Ty×N1 is satisfied, where Ty denotes a length in the y-direction of one period of an interference fringe which is formed on the photodetector 9 by reflected light of the zero-order diffracted light by an information recording surface other than the access-target information recording surface, reflected light of the positive-first-order diffracted light by the information recording surface other than the access-target information recording surface, and reflected light of the negative-first-order diffracted light by the information recording surface other than the access-target information recording surface, N1 denotes a positive integer, and Uy denotes each length in the y-direction of the divisional light-receiving elements 9e, 9f, 9g, and 9h.

Abstract: Disclosed herein are an optical recording medium driving device and an additional recording method, which performs tracking servo control for moving an objective lens in a direction orthogonal to a tangential direction of a guide track so that a guide tracking error signal is decreased with respect to a guide track of a guide layer separation type recording medium, detects an additional recording start position subsequent to a recorded track if the recorded track is present in a recording layer of the optical recording medium, generates a tracking correction signal according to the reproduction tracking error signal upon tracking servo control of the recorded track just before the additional recording start position, and corrects tracking servo control according to the tracking correction signal upon additional recording start.

Abstract: An optical pickup device includes a first light source emitting first light with a first wavelength, a second light source emitting second light with a second wavelength, a third light source emitting third light with a third wavelength, an objective lens having a step structure, the objective lens being disposed to satisfy predetermined conditions, at least one first coupling lens making the first light and the second light incident onto the objective lens as converged light, a second coupling lens making the third light incident onto the objective lens as diverging light, and a liquid crystal aberration correcting element.

Abstract: An optical pickup device has a semiconductor laser emitting light which is in turn branched via a diffraction grating into at least three beams of light including a main beam and two sub beams which are in turn condensed via an objective lens on an optical disk at a guide groove and reflected by the optical disk to provide three reflections of light which are in turn received by detectors, each divided into two regions, respectively, to generate a tracking error signal. The diffraction grating is divided into three regions including a first region, a second region and a third region located intermediate therebetween, each having a periodical structure out of phase, the periodical structure having grating grooves in a direction determined depending on the phase of the second region to incline relative to a direction perpendicular to the guide groove of the optical disk.

Abstract: An optical head apparatus is made to be downsized while obtaining an sufficient driving force of an objective lens actuator. The optical head apparatus includes a first optical system including a first objective lens for focusing a light beam upon an optical disc; a second optical system including a second objective lens for focusing a light beam upon an optical disc having an information recording density smaller than the optical disc which the first optical system irradiates upon, the second objective lens having a numerical aperture smaller than the first objective lens; and an up-orienting prism including a first reflecting surface for deflecting a light beam to an optical axis of the first objective lens in the first optical system, and a second reflecting surface for deflecting a light beam to an optical axis of the second objective lens in the second optical system.

Abstract: An optical pickup includes a wave plate on an optical path to be followed by every light beam emitted from three light sources (with wavelengths ?1, ?2 and ?3, respectively) both on their way toward an optical disc and back from the disc toward a photodetector. The wave plate has two layers with different retardations and different optic axis directions. The sum of the retardations of the first and second layers is defined to be approximately 5/4?1, 3/4?2 and 1/2?3 to the light beams with the wavelengths ?1, ?2 and ?3.

Abstract: An optical integrated device includes a light source; a light splitting-and-guiding section that splits a reflected light beam into two end light beams, a connection light beam, and a residual light beam, and guides the two end light beams and the connection light beam in directions different from a direction of the residual light beam; and a light receiving section that receives the two end light beams and the connection light beam with photodetection devices divided, in the tangential direction, into at least two regions within a range in which the connection light beam is incident, receives the residual light beam with photodetection devices divided, in the tangential direction, into regions having widths corresponding to portions on which the two end light beams are incident, and outputs a detection signal in accordance with an amount of light received with each of the photodetection devices.

Abstract: An optical drive device includes first and second light sources, an objective lens configured to receive a first light emitted from the first light source and a second light emitted from the second light source and to irradiate both the first light and the second light to an optical disc recording medium, a first focus mechanism configured to drive the objective lens in a focus direction, a second focus mechanism configured to change collimation of the second light incident to the objective lens and changing the focusing position of the second light independently of the first light, a first focus servo control unit configured to drive the first focus mechanism, an error signal subtraction unit configured to subtract the first focus error signal from a second focus error signal, and a second focus servo control unit configured to drive the second focus mechanism.