Abstract: An optical pickup device includes a light source to emit light, an objective lens to focus the light on a recording medium to form a light spot, an optical path changer on an optical path between the light source and the objective lens to change the path of incident light, a chromatic aberration correction lens disposed on an optical path between the light source and the objective lens, and a photodetector to receive light which is reflected from the recording medium and is then incident thereon through the optical path changer. The chromatic aberration correction lens corrects a chromatic aberration occurring due to a change in the wavelength and/or due to an increase in a wavelength bandwidth of the light. The chromatic aberration correction lens includes at least two lenses such that a lens having a positive power and a lens having a negative power are adjacent to each other.

Abstract: An optical pickup device includes a plurality of laser light sources emitting laser beams of different oscillation wavelengths, and a plurality of objective lenses on which the laser beams in the form of diverging beams emitted by the plurality of laser light sources are incident, and which directly focus the laser beams onto a recording surface of an optical disc. A rising mirror reflects a laser beam in the form of a diverging beam emitted by a laser light source of a predetermined oscillation wavelength among the plurality of laser light sources so as to lead the laser beam to one of the plurality of objective lenses, and transmits the laser beam in the form of a diverging beam emitted by the other laser light source. As the rising mirror transmits the laser beam in the form of the diverging beam emitted by said other laser light source, astigmatism is generated so as to correct existing astigmatism of the laser beam emitted by said other laser light source.

Abstract: An optical disc apparatus for use of an optical disc including a plurality of recording layers sets an amount of correction of spherical aberration for each of the recording layers of the disc during a focus sweep. A photodetector portion produces a signal in response to returned light for each of the recording layers.

Abstract: An optical information recording method of recording information three-dimensionally by irradiating a laser light beam onto a medium having a servo information plane on which address information and/or servo information is recorded, is disclosed. The method includes the steps of: dividing a laser light beam from one laser light source into laser light beams, the beam including a first light beam for reading the information, and a second light beam for recording information onto the recording medium; irradiating the first light beam onto the servo information plane to read the information from reflected light of the first light beam to read the information in which optical axes of the first light beam and second light beam are arranged coaxially; and irradiating the second light beam based on the read information to be focused onto a position in a depth direction perpendicular to a horizontal direction of the recording medium.

Abstract: An optical pickup device capable of eliminating interlayer crosstalk which is responsible for fluctuation in control signals and error rate in data signals, thereby ensuring stable action for a multilayered recording disc with a narrow interlayer spacing. The reflected beam coming from the multilayered disc is divided along the central line into two parallel portions by the dividing optical system and then condensed. The reflected beam coming from the active layer, which has been condensed, is reflected by the reflecting plane whose reflecting region is limited and the thus reflected beam is detected by the optical detector. The reflected beam coming from other layers is not reflected by the reflecting plane, so that interlayer crosstalk is reduced.

Abstract: A temperature sensor is disposed in an optical pickup to detect a temperature of an objective lens. An optical element (for example, a collimator lens) is driven according to a temperature change of the objective lens, which corrects deterioration of an optical characteristic of a laser beam passing through the objective lens. Good recording/reproduction is smoothly performed even if the optical characteristic of the objective lens is changed with the temperature change.

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: An optical pickup apparatus comprising: a laser diode; an objective lens made of synthetic resin arranged in an optical path of laser light between the laser diode and an optical disc so that the laser light from the laser diode is focused onto a signal recording layer through a protection layer of the optical disc; and an aberration correction element interposed in an optical path of the laser light between the laser diode and the objective lens, the aberration correction element configured to be operated so as to correct spherical aberration caused by moisture-absorption characteristics of the objective lens.

Abstract: An optical pickup apparatus comprising: an objective lens configured to focus laser light having the Gaussian distribution properties emitted from a laser diode to a signal recording layer of an optical disc; and an adjustment coating formed on a surface of an incident face of the objective lens on which the laser light is to be made incident, the adjustment coating being configured to adjust transmittance of the laser light passing through the objective lens, the adjustment coating being formed on the surface of the incident face such that the transmittance is lowered as a numerical aperture of the objective lens is reduced.

Abstract: An optical storage system and a spherical aberration (SA) compensation apparatus and method thereof are provided. The SA compensation apparatus includes a microprocessor and a digital-signal-processor (DSP). The microprocessor repeatedly regulates a compensation value of an SA compensation driver in the optical-pickup-head (OPH) after the microprocessor has determined the type of an optical storage medium and before the OPH has focused on the optical storage medium. The DSP processes a plurality of electrical signals converted through the OPH whenever the microprocessor has regulated the compensation value of the SA compensation driver, so as to obtain width values of a plurality of focus-error (FE) signals. Accordingly, the microprocessor makes the SA compensation driver to drive an SA compensation unit according to the width values of the FE signals, so as to compensate an SA of the light point generated by the OPH and focused on the optical storage medium.

Abstract: Disclosed is an objective lens used for an optical pickup apparatus to perform writing and/or reading of an optical information recording medium, comprising an antireflective film on a surface of a light source side, wherein a light flux of wavelengths including a wavelength ?1 of 380 nm??1?420 nm and a wavelength ?2 of 630 nm??2?810 nm, is condensed on the medium, a numerical aperture on the light source side with respect to the wavelength ?1 is within a range of 0.8-0.9, and that with respect to the wavelength ?2 is 0.7 or less, and a band of the antireflective film is within a range of 700 nm-800 nm in a state where a reflectance of a light flux perpendicularly entering a central portion of the surface in a wavelength region from 400 nm to 1200 nm is 3.0% or less.

Abstract: An objective lens driving apparatus includes an objective lens (13) collecting a light flux emitted from a light source on a optical disk (11), and a lens holder (14) holding the objective lens (13). The lens holder (14) includes a first bonding portion (14i) and a second bonding portion (14j) for holding the objective lens (13) by means of bonding. The objective lens (13) is fixed to the lens holder (14) by applying a first bonding adhesive (25) to the first bonding portion (14i) to thereby bond the objective lens (13) thereto, adjusting an inclination of an optical axis of the objective lens (13) while causing the first bonding adhesive (25) to deform, and applying a second bonding adhesive (26) to the second bonding portion (14j). The second bonding adhesive (26) has a larger Young's modulus after curing than the first bonding adhesive (25).

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: 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 pickup includes a light emitting component, an optical component and a base component. The light emitting component has a laser diode, a package and a holder. The package has a positioning recess formed in an outer peripheral face of the package. The holder holds the package in a fitting hole of the holder. The holder has a protrusion component that is formed in an inner peripheral face of the fitting hole of the holder and is fitted to the positioning recess of the package, and a guide component that extends from the protrusion component by a first specific height beyond an end face of the holder. The protrusion component has a width in a peripheral direction of the fitting hole that is at least equal to a width of the positioning recess of the package in a peripheral direction of the package.

Abstract: Disclosed herein is a recording medium on or from which the recording or reproduction of data is stably performed. On the recording medium, data are recorded three-dimensionally by the irradiation of a recording laser beam. The recording medium includes a reflection control layer including a plurality of reflection layers stacked in a film thickness direction, each reflection layer having a connection terminal, each reflection layer exhibiting reflectivity and transmissivity changeable in response to an electrical signal supplied to the connection terminal and a recording layer disposed at a beam incidence side of the reflection control layer.

Abstract: A spatial light modulator (SLM) having a phase mask that is provided as an internal component thereof. The phase mask can be provided as a multilevel surface of relatively higher index of refraction material on an inner surface of a transmissive cover window or as a separate transmissive window between the cover window and the pixels of the SLM. If the phase mask is to be used with a liquid crystal SLM, then it may be desirable to planarize the surface of the cover window contacting the liquid crystal by providing a layer of relatively lower index of refraction material adjacent the multilevel surface. The phase mask can also be provided on the transmissive cover window by patterned ion deposition, exposing patterned light to a photopolymeric material, or in some other suitable fashion. Arranging for the pixel electrodes to be at one of multiple levels rather than lying in an exactly planar relationship can also effectively create the phase mask.

Abstract: An interference-type optical pickup, an optical information detection method, and an optical information recording and reproducing apparatus, which allow easy adjustment of a path difference between two lights, have a high signal amplification effect and are suitable for size reduction of an optical system, are provided. A signal light reflected from an optical disk and a reference light branched from the same light source and guided into detectors without being projected onto the optical disk are caused to interfere with each other on detectors. Detector outputs in four interference states in which phase relationships between the reference light and the signal light are different from each other by degrees are simultaneously obtained and calculated. Accordingly, a readout signal RF that is always stable and amplified with high quality is obtained even when an optical path changes due to disk undulations.

Abstract: Chemically-bonded laminated polymer achromatic polarization devices, such as circular polarizers, are disclosed for use in optical disc (e.g., CD/DVD) pickup heads. Chemically-bonded laminated polymer achromatic polarization devices have the benefit of providing stable retardation and optic axis over an extended wavelength range, thereby ensuring orthogonal polarization in double-pass for two or more laser wavelengths. Moreover, the chemically-bonded laminated polymer achromatic polarization devices can be symmetric in construction, such that there is no specific input and output side. This alleviates the need to produce geometries that prohibit inversion of the part when installed in the system. Manufacturing processes that produce chemically-bonded laminated polymer achromatic polarization devices, with high light efficiency, durability and robust performance in a variety of environmental conditions are disclosed.

Abstract: An optical pickup apparatus comprising: a laser light source; an objective lens; a reflection mirror; a photodetector; and a beam splitter, the beam splitter including a first reflective film configured to generate a first phase difference corresponding to a predetermined wavelength with respect to laser light, the reflection mirror including a second reflective film configured to generate a second phase difference corresponding to the predetermined wavelength with respect to the laser light, the first reflective film and the second reflective film being formed so that a combined phase difference of the first phase difference and the second phase difference becomes substantially quarter-wave with respect to the laser light.

Abstract: The recording accuracy of information on an optical disc is increased. An information optical system (150) of an optical disc apparatus (110) enables a semiconductor laser (3) to sequentially output specific peak light (LEP) and specific slope light (LES) as an information light beam (LM) and enables the correction lens (162) to change the divergence angle of the specific peak light (LEP) so that an absorption change area (RA) by the specific peak light (LEP) can be positioned at a far position in the recording layer (101). Thus, it is possible to form an energy concentration area (RE) by the specific slope light (LES) in the vicinity of a target position (QG), and the recording accuracy of information on the optical disc (100) can be increased.

Abstract: An optical pickup has a semiconductor laser device that can emit laser beams with different wavelengths. A beam splitter and objective lens direct the emitted beam onto a rotating optical disc. Reflected light returns through the objective lens and beam splitter to a photodetector. A pair of liquid crystal elements on the optical path from the optical disc to the photodetector have controllable lens functions acting in different directions to produce an adjustable astigmatic effect that enables the photodetector to generate a focus error signal with a linear range appropriate for the type of optical disc, the number of signal layers in the optical disc, and the spacing between the layers.

Abstract: An optical-pickup hologram element has six regions on an x-y plane, divided as follows: the first region with a first line (an x-axis) and a second line that connects points (?xa, 0) and (?xb, yb); the second region with the first and second lines and a third line connecting points (xa, 0) and (xb, yb); the third region with the first and third lines; the fourth region with the first line and a fourth line connecting the point (xa, 0) and a point (xb, ?yb); the fifth region with the first and fourth lines and a fifth line connecting the point (?xa, 0) and a point (?xb, ?yb); and the sixth region with the first and fifth lines (xa<xb and ?xb<?xa). The second and fifth, and the other regions are given astigmatism at different angles to the second line.

Abstract: An optical head is provided with a light source for outputting laser light having a wavelength of 430 nm or less; an objective lens for collecting the laser light outputted from the light source to an optical disc having a plurality of information recording surfaces; a light receiving element for receiving laser light reflected on the optical disc; and a detecting lens for guiding the laser light reflected on the optical disc to the light receiving element. The detecting lens is formed of a resin material. The detecting lens is arranged so that a light collecting position of the laser light reflected on an information recording surface different from an information recording surface having a thinnest protection substrate, among the information recording surfaces, is outside the detecting lens, at the time of recording or reproducing information on or from the information recording surface having the thinnest protection substrate.

Abstract: A photodetector comprising: a first light-receiving surface configured to receive reflected light of zero-order light generated based on a laser beam, from one information recording layer of a multilayer optical disc; a second light-receiving surface that is adjacent to the first light-receiving surface with a predetermined interval, the second light-receiving surface being configured to receive reflected light of diffracted light generated based on the laser beam, from the one information recording layer; and a third light-receiving surface for canceling out reflected light of the zero-order light from other information recording layer of the multilayer optical disc, received by the first light-receiving surface or the second light-receiving surface, the third light-receiving surface being configured to receive the reflected light of the zero-order light from other information recording layer.

Abstract: To provide an optical pickup and an optical information device, capable of obtaining excellent signal characteristics for an optical disk on and/or from which recording and/or reproducing are performed using a laser. The optical pickup includes an optical detector, a support holder for holding the optical detector, and an optical base for fixing the support holder. The support holder has at least two notches at its both ends, the optical base has convex portions corresponding to the notches of the support holder, the optical base and the support holder are fixed by photo-curable adhesives for bonding the convex portions and the support holder to each other, and the shortest distance between the side faces of the convex portions, which do not face each other, is equal to or less than the width of the support holder in the direction of right and left ends.

Abstract: The optical scanning device [10] is arranged for scanning a record carrier [1]. The record carrier has an outer face [7]. The scanning device comprises a radiation source [11] for generating a radiation beam [12] and an objective system [25] having an exit face [26] arranged for evanescent coupling of the radiation beam between the exit face and the outer face and for converging the radiation beam to a focus [27]. A tilt measuring system [67, 77] provides a tilt signal [87; 88] representing a tilt angle between the objective system and the record carrier. A control unit [95] determines a distance signal representing a distance between the exit face and the focus from the tilt signal.

Abstract: An optical device includes a sub-mount 2 mounting first and second semiconductor lasers 1a, 1b and having an onboard part for the semiconductor lasers and an optical-path conversion mirror 7 integrated with each other, and a light receiving element 11 arranged on a light receiving element substrate to have first and second light receiving regions separated from each other by at least one parting line. In the optical device, one light gravity center of an optical spot, which is formed on the light receiving element 11 by homeward flux of light emitted from the first semiconductor laser 1a and reflected by an optical disc 55, and another light gravity center of an optical spot, which is formed on the light receiving element 11 by homeward flux of light emitted from the second semiconductor laser 1b and reflected by the optical disc 55 are together positioned on the parting line.

Abstract: Light emitted from a radiation light source 1 passes through a diffraction grating 3a and is separated into transmitted light a and +1st/?1st order diffracted lights b, c. These lights are collected through an objective lens 7 on tracks of an optical disc 8 in a partially overlapped state. Light reflected by the tracks passes through the objective lens 7 and is incident upon light diverging means 13a. Subsequently, light corresponding to the transmitted light “a” diverges into two light beams that are respectively incident upon light detection regions A1, A2, light corresponding to the diffracted lights “b” and “c” respectively diverges into two light beams that are respectively incident upon light detection regions B1, B2, and C1, C2. A tracking error signal associated with the tracks of the optical disc 8 is generated by combining signals detected in the light detection regions A1, A2, B1, B2, C1, and C2.

Abstract: An optical disk apparatus includes a light source that emits a light flux. A light source drive circuit causes the light source to emit the light flux. An optical base has an optical system disposed thereon. The optical system includes an objective lens for guiding the light flux emitted from the light source to a disk-shaped recording medium. A moving mechanism moves the optical base. A first heat radiation member is connected to the light source, and a second heat radiation member is connected to the light source drive circuit and is different from the first heat radiation member. The first heat radiation member and the second heat radiation member are provided so as to face the disk-shaped recording medium. The first heat radiation member is disposed on the disk-shaped recording medium side with respect to the second heat radiation member, and the first heat radiation member has a hole provided therein, for exposing the second heat radiation member to the disk-shaped recording medium.

Abstract: A compound having a good durability against light and capable of producing desired liquid crystallinity after polymerization, and a polymerizable liquid crystal composition containing such a compound, are provided. Further, an optical element having a good durability against light, and an optical information writing/reading device employing such an element, are provided. A compound represented by CH2?CR1—COO—R2-Cy-Ph-R3—OCO—CR4?CH2. R1 and R4 are each preferably a hydrogen atom. R3 is preferably a C1-6 alkylene group wherein an oxygen atom is present or not present at an end of the group to be bonded to a cyclic group, and wherein some or all of hydrogen atoms bonded to carbon atoms in the group may be substituted by fluorine atoms; or an alkylene group wherein an oxygen atom is present at an end of the group to be bonded to a cyclic group.

Abstract: Disclosed herein is an optical detection method and optical detection apparatus, the apparatus including: a light irradiation section configured to irradiate a laser beam upon one of fine particles which are successively fed in a flow path; and a light detection section configured to detect fluorescent light and/or scattered light generated from any of the fine particles upon which the laser beam is irradiated; the method including the steps of: irradiating a laser beam upon one of fine particles which are successively fed in a flow path; and detecting fluorescent light and/or scattered light generated from the fine particle; wherein the laser beam being formed as a pulse laser beam whose pulse intensity is modulated such that one laser beam or two or more laser beams having different wavelengths are irradiated by a plural number of times upon one fine particle with the intensity varied.

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: A holographic recording and reproduction system includes a servo optical path, which is used to provide a servo mechanism, so that holographic interference fringes can be stored continuously into a holographic recording medium, and when the reproduction signals are desired, they can be fetched and obtained swiftly and accurately by making use of the servo mechanism. In addition, the servo light spot of the servo optical path is located on the optical axis of an object lens, thus reducing the image aberrations produced and raising the quality of the signals read for the servo track searching. Moreover, the light intensity distribution of the reference beams reflected by the holographic recording medium is monitored and controlled, as such realizing the analysis and adjustment of the relative distance and inclination angle between the holographic recording and reproduction system and the holographic recording medium.

Abstract: An optical pick-up to perform recording or reproducing for an optical recording medium is disclosed, which includes a light source configured to emit a light beam, an objective lens configured to focus the light beam onto the optical recording medium, and an aberration generation device provided between the light source and the objective lens, configured to generate coma aberration for the beam focused by the objective lens, based on a detected value from a device configured to detect a degree of tilt of the optical recording medium, wherein the tilt is compensated for by the coma aberration generated by the aberration generation device.

Abstract: A gap servo control method and apparatus for increasing a disturbance cancellation capability and decreasing the occurrence of an overshoot in a near-field optical disc drive include: generating an actuator driving signal of a transient response process by using a signal obtained by removing a disturbance contained in the gap error signal using a first band when a level of a gap error signal reaches a first level; and generating the actuator driving signal of the transient response process by using a signal obtained by removing the disturbance contained in the gap error signal using a second band when the level of the gap error signal reaches a second level.

Abstract: An optical pickup device radiates laser light to a disc having a plurality of recording layers in a direction of lamination. The optical pickup device includes an astigmatic element and a spectral element. The astigmatic element allows reflected light from the disc to converge in a first direction and form a first focal line at a first position, and allows reflected light to converge in a second direction and form a second focal line at a second position closer to the disc than the first position. The spectral element splits a reflected light flux in two along a straight line parallel to the first direction and turns traveling directions of the split two light fluxes into directions separated from each other. Here, the spectral element is interposed between the second focal line of the reflected light from a target recording layer and the second focal line of the reflected light from a deeper recording layer than the target recording layer.

Abstract: A tilt sensor includes a photodetector having a photosensitive plane and detecting a light beam in multiple areas and outputting detection signals representing its intensities and a tilt detector for generating a tilt error signal, including information about the tilt of a disk, based on the detection signals. The light beam forms a beam spot on the photosensitive plane. The beam spot includes a +first-order light area in which zero-order and +first-order light rays, diffracted by a track on the disk, are superposed, ?first-order light area in which zero-order and ?first-order light rays are superposed, and a zero-order light area which is sandwiched between the +first-order and ?first-order light areas, includes neither the +first-order nor ?first-order light ray, but includes a zero-order light ray. The photodetector generates the detection signals except for light entering an opaque area provided for at least part of the zero-order light area.

Abstract: An optical pickup apparatus for reproducing information from an optical disk, includes: a semiconductor laser applying a beam to an optical disk having two recording layers through an objective lens; and a light receiving device to which light reflected from the optical disk is directed through the objective lens and a beam splitting device, wherein: the beam splitting device has two first light receiving areas for detecting a push-pull signal and a second light receiving area for detecting a focus error signal, and a configuration is provided such that the center of the optical axis of the reflected light in the beam splitting device is made to lie within the second light receiving area for detecting the focus error signal.

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 object of the present invention is to provide an extraction optical system capable of separating and extracting a signal light and a stray light with a simple configuration, and an optical head device including the same. A phase plate and a phase plate are +?/4 phase plates, while a phase plate and a phase plate are ??/4 phase plates. A focal line, a focal line and a focal line represent a focal line of a stray light, a focal line of a reproduction light and a focal line of a stray light, respectively. All beams of the reproduction light enter the state in which a polarization direction is rotated by 90 degrees after passing through the phase element. In contrast to the all light bundles of the reproduction light, polarization directions of all light bundles of the stray lights and are not rotated even after passing through the phase element.

Abstract: To provide a liquid crystal optical modulation element which is excellent in durability against blue laser and which can maintain the characteristics for a long period of time. A liquid crystal optical modulation element to modulate a laser beam having a wavelength of at most 500 nm, which comprises a layer of a polymer liquid crystal composition sandwiched between a pair of transparent substrates facing each other, characterized in that each of the pair of transparent substrates has an alignment film on the surface which faces the other transparent substrate, and the polymer liquid crystal composition is a polymer liquid crystal containing a hindered amine compound and a hindered phenol compound.

Abstract: A pickup device includes an irradiation optical system including an object lens for focusing light flux on a track of a recording surface of an optical recording media having a plurality of recording layers stacked while a spacer layer is interposed between the recording layers to form a spot and a detection optical system including an photo detector having a plurality of light receiving parts for receiving returning light reflected from the spot through the object lens to perform photoelectric conversion. The pickup device controls a position of the object leans according to an electrical signal calculated from outputs of the light receiving parts.

Abstract: To provide an optical pickup and an optical information device, capable of obtaining excellent signal characteristics for an optical disk on and/or from which recording and/or reproducing are performed using a laser. The optical pickup includes an optical detector, a support holder for holding the optical detector, and an optical base for fixing the support holder. The support holder has at least two notches at its both ends, the optical base has convex portions corresponding to the notches of the support holder, the optical base and the support holder are fixed by photo-curable adhesives for bonding the convex portions and the support holder to each other, and the shortest distance between the side faces of the convex portions, which do not face each other, is equal to or less than the width of the support holder in the direction of right and left ends.

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: An extreme ultraviolet light system includes a drive laser system that produces an amplified light beam; a target material delivery system configured to produce a target material at a target location; a beam delivery system configured to receive the amplified light beam emitted from the drive laser system and to direct the amplified light beam toward the target location; and a metrology system. The beam delivery system includes converging lens configured and arranged to focus the amplified light beam at the target location. The metrology system includes a light collection system configured to collect a portion of the amplified light beam reflected from the converging lens and a portion of a guide laser beam reflected from the converging lens. The light collection system includes a dichroic optical device configured to optically separate the portions.

Abstract: A beam irradiation device includes a light source for emitting laser light, an actuator for displacing a propagation direction of the laser light in accordance with a control signal, and a scan expansion lens for increasing a swing width of the laser light to be generated by the actuator. A spectral element is arranged between the actuator and the scan expansion lens. The spectral element allows at least a part of the laser light to be incident from the actuator to transmit, and reflects at least a part of the laser light to be incident from the scan expansion lens. The beam irradiation device further includes a light detector for receiving the laser light to be reflected on the spectral element to output an electrical signal.

Abstract: When first-order diffracted beams leak into a region, which is for receiving only a zeroth-order diffracted beam from an optical disc, due to positional displacement between an objective lens and a hologram element, an offset compensation signal includes an AC component, the offset compensation signal preferably including a DC component only. Accordingly, there may be caused deterioration in a modulation degree of the tracking error (TE) signal. A partial light shielding element 110 is formed on a hologram surface 112a along boundaries between a light receiving region (121a), which receives a zeroth-order diffracted beam, and light receiving regions (121b, 121c), which receive the zeroth-order diffracted beam and first-order diffracted beams, so as to cover the light receiving region (121a). Further, the partial light shielding element 110 shifts phases of transmitted light beams by ?, whereby the TE signal is offset-compensated, and the modulation degree can be improved.

Abstract: An objective lens for converging light emitted from a light source on an optical recording medium to record and reproduce information consists of a single lens having at least one aspheric surface. The following conditional expressions (1) to (3) are satisfied: N?1.75??(1) 0.5<f/f1<0.6??(2) 0.8<d/(NA·De)<1.0??(3) where N denotes a refractive index, f denotes a focal length (mm), f1 denotes a focal length (mm) of a light source side surface, d denotes a thickness (mm) on an optical axis, NA denotes a numerical aperture on an optical recording medium side, and De denotes an effective aperture (mm) of the light source side surface.

Abstract: An optical disk drive for recording information on a recording surface of an optical disk and reading information recorded in the optical disk is provided. The optical disk drive includes a spindle to rotate the optical disk and a carriage movable in parallel with a tracking direction of the optical disk. The carriage includes a laser light source to emit laser light, a collimator lens to convert divergent light into parallel light and is arranged with an optical center thereof being in a farther and offset position with respect to an optical axis of the laser light, a reflecting mirror to receive and deflect the laser light transmitted through the collimator lens in a direction perpendicular to the recording surface of the optical disk, and an objective lens to converge the laser light deflected by the reflecting mirror on a position corresponding to the recording surface of the optical disk.