Abstract: An optical pickup apparatus includes: a first light source; a second light source; a light-converging optical system including a coupling lens and an objective lens; and a photodetector. The optical pickup apparatus is capable of recording and/or reproducing information by converging a light flux from each of the first and second light sources with the light-converging optical system on an information recording surface of each of first and second optical information recording media through a protective layer, and by detecting the light flux reflected from the information recording surface and passing through the light-converging optical system again, on the photodetector. The optical pickup apparatus satisfies predetermined conditions according to an optical path length from each of first and second light sources and the information recording medium, a magnification of the objective lens, and a magnification of the light-converging optical system.

Abstract: An optical head device has at least one upward-reflecting mirror, objective lenses, an objective lens actuator, and a moving mechanism. The upward-reflecting mirror receives an incident luminous flux having a wavelength emitted from a semiconductor, and changes its direction. The objective lenses having mutually different numerical apertures condenses the luminous flux whose direction has been changed by the upward-reflecting mirror to radiate a condensed luminous flux onto an information recording medium. The objective lens actuator moves the objective lenses in the focus direction of the information recording medium so that the luminous flux incident on the information recording medium becomes in a focused state. The moving mechanism moves the upward-reflecting mirror so that the luminous flux is incident on the information recording medium via any one of the objective lenses.

Abstract: A quarter-wave plate includes a base member including a ridge and trough periodic structure with a structural period of ?min/2<P<?min arranged on one side of the base member, where ?min is the minimum wavelength among the wavelengths of a plurality of light fluxes which pass the quarter-wave plate. In the quarter-wave plate, refractive index of a ridge portion of the ridge and trough periodic structure for the wavelength ?min and a light transmittance have predetermined values. The ridge and trough periodic structure satisfies the predetermined condition relating to the structural height and the structural width of the ridge portion.

Abstract: Provided is an optical recording head in which a light beam from a light source is collected by an optical element and reflected on a reflecting surface to be formed into a spot light. Since a support portion for supporting the light source of the optical element at a predetermined position and the reflection surface for reflecting the light beam are formed integrally with each other, it is not required to perform the positioning thereof, and light can be collected to a very small spot with high efficiency, and an optical recording head and an optical recording apparatus having low heights can be provided.

Abstract: An optical pickup device such that the driving force of the drive unit provided on the same optical base as that of the objective lens exerts no adverse influence on controlling of the objective lens is provided. The optical pickup device 1 has an objective lens 11 that condenses laser light onto an optical disk 3, a first drive mechanism 15 that moves the objective lens 11 on the optical base 6, a second drive mechanism 8 that moves a movable member 9 different from the objective lens 11 on the optical base 6, first control means 27 that outputs a first driving signal TDS to operate the first drive mechanism 15, and second control means 25 that outputs a second driving signal EDS to operate the second drive mechanism 8. A derivative value of the second driving signal EDS is added to the first driving signal TDS and inputted to the first drive mechanism 15.

Abstract: The light emitted from a semiconductor laser is divided by a diffractive optical element into three light beams which are 0th-order light as the main beam and ±1st-order diffracted lights as the sub-beams, and the track error signals by the main beam and the sub-beams are detected, respectively, by a differential phase detection method. By the effect of the diffractive optical element, the light intensity distributions of the main beam and the sub-beams become different when making incidence on an objective lens. Therefore, when there is radial tilt in a disk, the phases of the track error signals by the main beam and the sub-beams are shifted with each other. Based on the shift in the phases of the track error signals, radial tilt of the disk is detected.

Abstract: Multi layer near-field optical recording using a moderate numerical aperture (NA) is superior to the high-NA (NA=2.0) first-surface single-layer technique. The use of very flat and thin spacer layers limits spherical aberration due to difference in layer depth. The thin spacer layers may have a high refractive index because their thickness allow for a relatively high absorption constant. This makes possible in principle an m-layer system, e.g. m=4, with NA=1.6 which may include a flat, protective cover layer. Further a medium for use in such a system is described.

Abstract: An optical head and an apparatus using the optical head are shown. The optical head includes a light-emitting element, a first polarized light diverging element for transmitting the light beam of a first polarization direction and reflecting the light beam of a second polarization direction orthogonal to the first polarization direction, a second polarized light diverging element for transmitting or reflecting the light beam of the first polarization direction, a converging element for converging the light beam on an information recording medium, a reflection element for reflecting a first reflected light beam reflected on the information recording medium and reflected on or transmitted through the second polarized light diverging element, and a detection element for detecting a second reflected light beam reflected on the reflection element and transmitted through or reflected on the second polarized light diverging element.

Abstract: An optical pickup apparatus for use with a semiconductor laser which outputs a light beam, the optical pickup apparatus has; a diffraction grating for diffracting the light beam into diffracted light; a collimator lens for rendering the diffracted light diffracted by the diffraction grating as a parallel beam; an objective lens for focusing the parallel beam towards an optical information recording medium; a hologram element for diffracting return light reflected from the optical information recording medium; a plurality of light receiving elements for receiving the diffracted light diffracted by the hologram element; and an incidence preventing area placed between the hologram element and the light receiving elements for, in the case where the light beam is focused on the recording surface on a side close to the objective lens out of recording surfaces of multilayer of the optical information recording medium, substantially preventing reflected light from the recording surface on a side remote from the ob

Abstract: An optical recording device includes a light source, a light-converging optical system, a moving unit, detection unit, and an acquisition unit. In the optical recording device, interference fringes from a recording light are shift multi-recorded as a plurality of pages of holograms within each of a plurality of planes corresponding to a plurality of convergence positions based on light exposure amount of each page, acquired by the acquisition unit, for each of the convergence positions.

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: When recording on and/or reproducing from an information recording medium having a plurality of recording layers is performed, there has been a problem in appropriately detecting a control signal at the time of the recording and/or reproducing, since reflected light from a recording layer, which does not undergo the recording and/or reproducing, enters a photodetector concurrently with reflected light from a recording layer which undergoes the recording and/or reproducing. In the present invention, a polarization hologram is used to diffract light outputted from a light source and to generate a main beam, which is a zeroth-order light beam, and a pair of sub beams, which is a positive first-order light beam and a negative first-order light beam each having a polarization direction perpendicular to a polarization direction of the main beam.

Abstract: An optical disc apparatus can make the focus of an information light beam converged by an objective lens agree with a target track of a target mark layer of an optical disc by appropriately predefining the distance between the focus of a servo light beam and that of the information light beam with regard to the direction of the thickness and a radial direction of the optical disc by means of the optical pickup of the apparatus and then operating for focus control and tracking control of the objective lens so as to make focus of the servo light beam converged by the objective lens agree with a reference track of a reference mark layer.

Abstract: An optical pickup according to the present invention includes: a light source 1d for irradiating an optical disk 4 with light; a lens 3 for converging the light onto the optical disk 4; a photodetector 1c having a plurality of detection regions 1cf, 1ct for detecting light which is reflected from a signal surface of the optical disk 4 and converting the light into an electrical signal; a hologram element 1a having a hologram region 1b for guiding the reflected light to the photodetector 1c; and a light-shielding plate 2 for blocking at least a portion of light transmitted through a region of the hologram element 1a other than the hologram region 1b. The light-shielding plate 2 includes a light shielding portion 2b for blocking light, and an aperture 2a for allowing the light to be transmitted therethrough.

Abstract: An optical pick-up device includes a laser source enabling emission of at least two light beams with different wavelengths, an objective lens which focuses the light beams emitted from the laser source on an optical disc, an optical detector which receives a light reflected from the optical disc, a front monitor which receives a part of the light beams emitted from the laser source, a front monitor light-guiding plate which guides part of the light beams emitted from the laser source to the front monitor. The front monitor light-guiding plate is arranged between the laser source and the objective lens, at least a part of a region of the front monitor light-guiding plate illuminated by the light beams emitted from the laser source has a predetermined shape which causes the light beams to change traveling direction thereof by refraction and then be guided to the front monitor.

Abstract: An optical pickup includes: a laser light source which outputs an divergent beam having an elliptical far-field pattern; a beam shaping element having at least one cylindrical plane and which shapes the divergent beam outputted from the laser light source into an divergent beam having a prescribed shape in which at least the length in the major axis direction of the elliptical shape is shortened; a light collecting portion having a beam splitter which perpendicularly collects the divergent beam that is outputted from the beam shaping element and which has a prescribed shape on the recording surface of an optical disk, and a mirror or the like; and a light detecting portion The optical axis of the divergent beam is rotated so that the direction in which the major axis of the divergent beam having a prescribed shape is shortened conforms to the radial direction of an optical information recording medium.

Abstract: An optical pickup for performing recording and/or playback of information by selectively irradiating the corresponding wavelength optical beam to first through third optical discs having a protection layer with different thickness, includes emission units for emitting first-wavelength through third-wavelength optical beams corresponding to the respective optical discs respectively, a condensing optical device for condensing each wavelength optical beam on an optical disc signal recording face, a divergence angle transformation device, which can be moved in the optical axis direction, for transforming the divergence angle of each wavelength optical beam according to the moved position in the optical axis direction so as to obtain a predetermined divergence angle, and a detector having a common light receiving unit for receiving each wavelength optical beam separated by an optical path separating unit and returned, with the condensing optical device condensing each wavelength optical beam on the corresponding o

Abstract: The invention relates to a compact optical pickup for a micro optical drive, and to a micro optical drive using this compact optical pickup. According to the invention a pickup for optical recording media includes a light source for generating a light beam for reading from and/or writing to an optical recording medium, a flexible arm serving as a focus actuator, an objective lens situated on the flexible arm for focusing the light beam onto the optical recording medium, an optical bench for directing the light beam towards the optical recording medium, one or more detectors for detecting the light beam reflected by the optical recording medium, and a mirror, which is arranged inclined with respect to a transparent block of the optical bench, for directing the light beam reflected by the optical recording medium towards a first detector.

Abstract: A combined aspherical lens has an aspherical shape with an intermediate substrate thickness between the substrate thicknesses of a BD and an HD in a numerical aperture (NA) range for the HD, and an aspherical shape dedicated to the BD in an NA range for the BD only. The lens is designed such that wave aberration occurring through the NA range for the HD for BD reproduction has the same aberration form as but has an opposite sign to wave aberration occurring through this range for HD reproduction. Further, in the NA range for the HD, a pattern of annular transparent electrodes is optimized for a spherical aberration wavefront defocused to minimize the maximum inclination of the wave aberration. A phase shift applied is within plus or minus half wave excluding an integer wavelength of aberration.

Abstract: In laser welding an optical part to a pickup case of an optical pickup device, outgas deposition on a lens surface can be inhibited, and positional shifting of the optical part can be reduced. The optical part has a lens surface facing in an optical axis direction and a protruding part formed, to be joined to the pickup case, at an end portion thereof in a direction perpendicular to the optical axis. A joint surface between the protruding part and the pickup case extends in a direction parallel to the optical axis, and the joint surface is fixed by a weld portion formed by laser irradiation. The joint surface is parallel to a bottom surface of the pickup case, and the height from the bottom surface is approximately equal to the height of the center of the lens surface.

Abstract: An optical pickup device includes a diffraction grating for separating laser light into a main beam and two sub beams, a photodetector having a sensor pattern for receiving the main beam and the sub beams reflected on a recording medium having multiple laminated recording layers respectively individually, and a diffraction element for positioning the main beam and the sub beams reflected on a targeted recording layer to be irradiated on the sensor pattern, and diffracting the main beam and the sub beams reflected on a recording layer other than the targeted recording layer to be irradiated in such a manner that the main beam and the sub beams are not overlapped with each other on the sensor pattern.

Abstract: An apparatus for effecting at least one of recording and reproducing information includes first and second light sources having light intensity and for emitting a light beam having an emission wavelength different from each other, first and second photodetectors capable of generating an output, an optical system configured to guide a light beam emitted from the first light source to a recording medium and to guide a light beam reflected from the recording medium to the first photodetector, a separating optical element configured to guide a light beam emitted from the first light source to the second photodetector, the second photodetector receiving the light beam and generating an output based on the received light beam, and a control circuit for receiving the output generated by the second photodetector, and being configured to control the light intensity of the first light source based on the output of the second photodetector.

Abstract: The invention relates to a new method for focus capture in an optical drive comprising a collimator lens. Use is made of the pre-programmed collimator lens position to secure a baseline position of the laser spot at a position with respect to an optical record carrier placed in the optical drive such that the correct information layer on the optical record carrier is captured efficiently and accurately.

Abstract: In an information memory apparatus having minute areas for storing information arranged in x, y and z directions three-dimensionally, parallel rays are irradiated to a memory area MA in a direction perpendicular to a z-axis to take projection images of the memory area MA while rotating the memory area MA around the z-axis little by little. The light rays irradiated at this time have a size which covers at least a direction of an x-y plane of the memory area. A computation unit PU finds data and addresses of minute areas distributed three-dimensionally by performing computation based upon the principle of computer tomography on the projection images. As for data writing, a change is given to optical transmissivity or light emission characteristics by irradiating laser light focused by a lens OL placed outside the memory area to a desired minute area and causing heat denaturation within the pertinent minute area.

Abstract: An optical system includes an optical recording medium configured to store data and a light device configured to emit a beam of light to write the data to the optical recording medium or read the data from the optical recording medium. The optical system also includes a superlens positioned between the optical recording medium and the light device. The superlens is configured to focus the beam of light emitted from the light device to create a focused beam of light on the optical recording medium.

Abstract: An optical pickup lens includes a first surface to focus laser light for recording/playback on an optical disc, a second surface formed outside the first surface and radiated with laser light for lens tilt detection, and an antireflection coating to transmit the laser light for recording/playback, the antireflection coating being continuously formed on the first surface and a second surface.

Abstract: A recording medium includes a substrate having a microscopic pattern, which includes a shape of continuous substance of approximately parallel grooves formed with a convex shaped section and a concave shaped section alternating on a surface of the substrate. A recording layer is formed on the microscopic pattern and a light transmitting layer has a thickness of 0.05 mm to 0.12 mm formed on the recording layer. The microscopic pattern satisfies a relation of P??/NA, wherein P is a pitch of the convex shaped section, ? is a wavelength of a reproducing light beam and NA is a numerical aperture of an objective lens. The microscopic pattern also includes modulated address information formed on both side walls of the convex shaped section viewed from the light transmitting layer as a wobble, both the side walls being parallel to each other, and furthermore wherein the address information is modulated by the phase-shift keying modulation system.

Abstract: According to one embodiment, an optical recording head device includes a light source which outputs such a relaxation oscillation optical pulse that a full width at half maximum of a single pulse is 820 ps or less, a driving unit for driving the light source, an objective lens which converges emission light from the light source on a recording layer of a recording medium, and captures reflective light which is reflected by the recording layer of the recording medium, a distribution unit, placed between the light source and the objective lens, for distributing incident light, and a photodetection unit for receiving via the distribution unit the reflective light which is reflected by the recording layer of the recording medium, wherein a resonator length of the light source is 6560 ?m or less.

Abstract: The present invention provides an object lens actuator, an optical pickup, and an optical disk drive, which can increase the size of the object lens actuator driving a lens holder in the tangential tilt direction, and drive and control the lens holder with a small amount of drive current. An object lens actuator comprising a lens holder having an object lens and a first coil; a first magnet fixed to a yoke; plural elastic support parts for supporting said lens holder with a first fulcrum; a moving part for supporting said elastic support parts with a second fulcrum different from said first fulcrum, and a fixed part having a moving mechanism for moving said moving part, wherein said first coil and said first magnet constitute a first magnetic circuit, said first magnetic circuit makes said lens holder movable in a focusing direction, a tracking direction and a radial tilt direction of an optical disk for read/write, and said moving mechanism makes said moving part movable.

Abstract: Each of sensors (16a, 16b) has a light-receiving portion and a light-emitting portion and outputs a signal according to light received by the light-receiving portion. The sensors (16a, 16b) face an actuator movable portion (26) in the tangential direction. The sensors (16a, 16b) are symmetrically arranged with respect to the centerline of the actuator movable portion (26) in the radial direction. When the actuator movable portion (26) is displaced in the radial direction, an output of one of the sensors (16a, 16b) is greater than an output of the other. Then, the difference between the two outputs is obtained to detect the displacement of the actuator moving part (26) in the radial ditection.

Abstract: A laminated wave plate that corresponds to a plurality of wavelengths including at least two wavelengths of ?A and ?B, and includes a first wave plate disposed on an incident side and a second wave plate disposed on an emitting side, the first wave plate and the second wave plate being laminated in such a manner that their optical axes are intersected each other, includes the following equations from (1) to (5): ?A1=360°+360°×2NA ??(1); ?A2=180°+360°×NA ??(2); ?B1=360°×2NB ??(3); ?B2=360°×NB ??(4); and NB=(?nB/?nA)×(?A/?B)×(0.

Abstract: The present invention makes it possible to accurately and adequately adjust the position where sub beams are shone when performing tracking correction or CTC using three beams. The invention adjusts the positions where the sub beams are shone onto the surface of an optical disc DK by changing the angle of a diffraction grating 211 that is mounted inside an optical pickup. When performing adjustment, the angle of the diffraction grating 211 is performed in three stages: (i) rough adjustment, (ii) initial fine adjustment and (iii) continuous fine adjustment.

Abstract: An optical pickup apparatus and a drive apparatus having the same are provided. Second light-receiving elements or third light-receiving elements for receiving ±first-order diffraction light beams from a polarization hologram are arranged outwardly of a circular region having the optical axis of a zero-order diffraction light beam on a light detector as its center, a radius of which is expressed by (2×t/n)×(f2/f1), where f1 denotes a focal length of an objective lens, f2 denotes a focal length of a coupling lens, t denotes a maximum value of a light transmitting layer thickness, n denotes a refractive index of a light transmitting layer.

Abstract: An optical pickup includes an objective lens, a protection member for protecting the objective lens, and a lens holding member configured to hold these members. The optical pickup records and/or reproduces an information signal on and/or from an optical recording medium by condensing laser light through the objective lens. The protection member includes a bearing surface to contact a surface of an edge portion of the objective lens not facing the optical recording medium, an aperture to control a diameter of laser light to be incident on the objective lens, and a protection portion protruding toward the optical recording medium with respect to the objective lens. The bearing surface, the aperture, and the protection portion are integrally formed with one another.

Abstract: An optical pickup includes a blue laser source; a red laser source; an infrared laser source; a blue light objective lens focusing blue light emitted from the blue laser source onto an optical storage medium; and a red and infrared light objective lens focusing red light emitted from the red laser source and infrared light emitted from the infrared laser source onto the optical storage medium. The optical pickup contains a blue light startup mirror separating the blue light from the red and infrared light. The blue light startup mirror is disposed along optical paths extending from the blue laser source, the red laser source, and the infrared laser source to the blue light objective lens and the red and infrared light objective lens. The optical pickup also contains a low blue light transmittance plane and a low blue light reflectance plane along an optical branch path extending from the blue light startup mirror to the red and infrared light objective lens.

Abstract: According to one embodiment, the invention provides an optical disk device having an irradiation section which applies a laser beam to an optical disk, a detection section which receives a reflected light emitted from the irradiation section and reflected from the optical disk to output a detection signal, and a discrimination section which performs focus search using the irradiation section and the detection section and determines whether the optical disk is a triple layer optical disk on the basis of the detection signal upon performing focus search.

Abstract: A laser beam 32 reflected by an information layer of a multilayer optical disc 26 is reflected and split by reflecting surfaces 31a?, 31b, 31c and 31d to be incident on a photodetector element 36 as laser beams 33, 34 and 35. The laser beam 34 is collected on a light receiving region 38 for RF detection to generate an RF signal. The laser beams 33, 35 are incident on light receiving regions 37a, 37b for focus detection, and a focus error signal is generated by an SSD method. A laser beam 65 reflected by an information layer adjacent to the above information layer partially transmits through the reflecting surface 31a? to be imaged on a light receiving region 66 for tracking detection, and a tracking error signal is generated.

Abstract: [Problems] To provide an optical head device capable of obtaining a desirable track error signal and a lens position signal for both two types of optical media having different groove pitches. [Means for Solving the Problems] Light emitted from a light source is divided by a diffraction optical element (3a) into a main beam that is transmitted light, first sub beams that are positive and negative first order diffracted light beams, and second sub beams that are positive and negative second order diffracted light beams. The phase of the positive and negative first order diffracted light beams from regions (13a, 13c) and that of the positive and negative first order diffracted light beams from regions (13b, 13d) are shifted from each other by 180 degrees, and the phase of positive and negative second order diffracted light beams from regions (13a, 13d) and that of the positive and negative second order diffracted light beams from regions (13b, 13c) are shifted from each other by 180 degrees.

Abstract: In an optical head (10) used for an optical disc (30) in which light-transmitting layers largely change in thickness, a degree-of-diversion/convergence enlarging member (20) fixed between a collimating lens (4) and an objective lens (6) is arranged. With this configuration, a moving range of the collimating lens can be reduced, and the optical head can be miniaturized.

Abstract: A light source unit comprises a plurality of light sources emitting a plurality of light beams. A plurality of volume hologram elements are provided for the plurality of light sources respectively, each volume hologram element having a plane of incidence of an incoming light beam and a plane of outgoing radiation of a diffracted light beam which are perpendicular to each other, the plurality of volume hologram elements having mutually different Bragg conditions in which an optical intensity of a diffracted light beam is set to a maximum.

Abstract: It is an object of the present invention to maintain a light flux separating unit in a stable state with a high positioning accuracy relative to a physical deformation when the light flux separating unit is attached or a great temperature change after the light flux separating unit is attached, in an optical pickup device including in a casing a projection optical system, a light receiving optical system and the parallel flat plate shaped light flux separating unit that separates a light flux advancing in the light receiving optical system from a light flux advancing in the projection optical system. In the present invention, the light flux separating unit 23 fixes at least two parts of two surfaces opposed to each other to attaching parts 2C and 2D provided in a floor surface 2A side of the casing and a wall surface 2B side vertical thereto by two kinds of adhesive agents 41 and 42 whose hardness is respectively different after curing.

Abstract: An optical head apparatus of an optical information recording/reproducing apparatus is provided with a light source. An objective lens focuses an output light emitted by said light source on a disc optical recording medium for which a groove or a pit for tracking is provided. T photo-detector receives a reflected light reflected by said optical recording medium. A polarizing splitter unit splits said output light and said reflected light. A quarter-wave plate disposed between said polarizing splitter section and said objective lens. A birefringence compensating unit reduces a change in an amplitude of a track error signal caused by birefringence in a protective layer of said optical recording medium.

Abstract: Provided is a semiconductor laser driving device which enables to reduce unnecessary power consumption. The laser driving device includes: a laser driving section for supplying a driving current for causing a semiconductor laser to emit light; a temperature detecting section for detecting a temperature of the semiconductor laser; and a voltage control section for supplying a source voltage to the laser driving section while changing a voltage value of the source voltage in accordance with the temperature detected by the temperature detecting section. As a result, unnecessary power consumption can be reduced. An appliance having the aforementioned information laser driving device will make energy savings possible, and further make it possible to suppress temperature increases of the appliance.

Abstract: A light source emits light with a first wavelength and light with a second wavelength longer than the first wavelength toward an optical disk from adjacent positions. An optical receiver detects light reflected from the optical disk. An astigmatism-generating element generates light used for focus control in a condition where a focusing position on one of two perpendicular cross sections including an optical axis of the light reflected from the optical disk is located ahead of the optical receiver and a focusing position on the other cross section is located behind the optical receiver are included. The astigmatism-generating element is a Fresnel mirror configured to include a plurality of reflecting mirrors.

Abstract: An objective lens is moved with a disc irradiated with laser light. A maximum value FEmax and a minimum value FEmin of the focus error signal, and a maximum value FSmax of the amplitude of a focus sum signal are measured. “(FEmax?FEmin)/FSmax” is compared with a determination value to determine the type of a disc.

Abstract: It is intended to provide an optical disk apparatus which detects a light amount greater than zero even when used in conjunction with an optical disk substrate having a large birefringence, so that it is possible to properly read a signal without errors and properly perform optical disk controls. The optical disk apparatus includes: a light source for emitting light; an objective lens for converging the light onto a signal surface of an optical disk; a polarized beam diffraction element for diffracting the light reflected from the optical disk; a photodetector for detecting the light diffracted from the polarized beam diffraction element; and a wavelength plate disposed between the optical disk and the polarized beam diffraction element.

Abstract: An optical head device according to the present invention includes a splitting section for splitting a light beam having been reflected from an optical storage medium. The splitting section includes: a first main region transmitting a first interfering portion; a second interfering portion transmitting a second main region; and first and second sub-regions through which the first interfering portion is transmitted with a lower rate than in the first main region and through which the second interfering portion is transmitted with a lower rate than in the second main region. The splitting section splits the reflected light beam into: a first main light beam transmitted through the first main region; a second main light beam transmitted through the second main region; a first sub-light beam transmitted through the first sub-region; and a second sub-light beam transmitted through the second sub-region.

Abstract: An optical scanning device for scanning a record carrier (22), the record carrier having an outer face (24), wherein the optical scanning device comprises a radiation source system (2) arranged to generate radiation (3); an objective system (20) having an exit face (24), the objective system being arranged between the radiation source system and the record carrier; a radiation detector arrangement for generating detector signals representing information detected in the radiation after interaction with the record carrier; and a position control system (42) for controlling a gap size of a gap between the exit face of the objective system and the outer face of the record carrier, the position control system providing for evanescent coupling of the radiation across the gap.

Abstract: An objective lens formed of a synthetic resin material having characteristics of substantially not reducing transmittance of the objective lens when a first laser beam having a first wavelength passes through the objective lens, and reducing the transmittance according to an elapsed time to apply a second laser beam when the second laser beam having a second wavelength shorter than the first wavelength and longer than a wavelength of ultraviolet light passes through the objective lens, the objective lens being irradiated with the ultraviolet light in advance for a predetermined time such that a change in the transmittance for the second laser beam is set within a predetermined range.

Abstract: In a confocal optical system provided with a light source 13, a first focusing means 14, a second focusing means 16, an aperture 17, and a detector 18, the detector has plural light reception regions. A position displacement is detected by detecting an intensity distribution of an image caused by a position displacement between the focusing spot of the second focusing means 16 and the aperture 17 by the detector 18, and the position displacement is corrected by controlling the aperture position using driving means 19 and control means 20. Also, a position displacement of the aperture 17 in the optical axis direction is detected and corrected on the basis of a change in output of the detector 18 by oscillating the aperture 17 in the optical axis direction.