Abstract: This optical disk device includes a pickup, an offset means, a focus servo means, and a layer jump means. The offset means generates a focus error signal on the basis of the output of the pickup, and applies an offset voltage to that focus error signal. And the layer jump means performs layer jump operation, including kick start operation, kick end operation taking a second threshold value as a reference, brake start operation taking a third threshold value as a reference, and brake end operation. Moreover, before executing this layer jump operation, the layer jump means changes this second threshold value or this third threshold value, according to the value of the offset voltage.

Abstract: Plural grooves or lands formed in an information recording carrier include at least a wobbling region and data is recorded wobblingly in this wobbling region by frequency shift modulation while recorded digitally with a single or multiple waves as a channel bit.

Abstract: This optical disk device includes a pickup, a replay means, and an adjustment means. The pickup irradiates laser light upon an optical disk. And the pickup receives light reflected back from the optical disk, performs photoelectric conversion thereupon, and outputs an electrical signal. The replay means adds an offset voltage to an RF signal generated from the electrical signal, and performs replay by processing the RF signal. The adjustment means measures the error rate of the RF signal while changing the value of the offset voltage. And the adjustment means adjusts the offset voltage to that voltage at which the error rate is the lowest. During replay, the replay means adds to the RF signal this offset voltage which has been thus adjusted.

Abstract: A method (400) comprising recording content on at least one of a plurality of recording layers on an optical record carrier by means of a focused radiation beam, wherein the selection of the recording layer for recording the content is based on at least one of the following recording criteria: —characteristics of the content; —properties of the plurality of recording layers; —manual selection by an end user; and —automatic selection is disclosed. The method is useful for recording content on multi-layer optical discs such as DVD and Blu-raydiscs.

Abstract: An information reproducing apparatus (1) is provided with: an offset adding device (19-1, 19-2) for adding an offset value (OFS) which can be set to be variable, to a read signal (RRF) read from a recording medium (100); a correcting device (18) for correcting waveform distortion occurring in a read signal corresponding to a long mark, of the read signal to which the offset value is added; and a waveform equalizing device (18) for performing a waveform equalization process on the read signal in which the waveform distortion is corrected.

Abstract: An optical disk driving apparatus includes an optical head device having a laser light source, a converging optical system converging a light beam emitted by the laser light source onto an optical disk, a photo detector receiving reflected light reflected by the optical disk, and an aberration correcting optical system controlling aberration of the converging optical system; a motor rotating the optical disk; and a control section receiving a signal from the photo detector, wherein the converging optical system has an objective lens formed using resin as a main material, the aberration correcting optical system has a spherical aberration correcting element correcting spherical aberration, and the control section evaluates quality of a reproduction signal for information in the optical disk by using the reflected light received by the photo detector, and utilizes a result of the evaluation to perform closed loop control on the spherical aberration correcting element.

Abstract: Provided are a resin composition comprising 100 parts by mass of the polymer having an alicyclic structure at least in a part of a repeating structural unit and 0.05 to 5 parts by mass of a hindered amine compound having a carbon atom at a ratio of from 67% by weight to 80% by weight in the molecular structure and having a molecular weight of from 500 to 3500, a novel piperidine derivative having a piperidylaminotriazine skeleton, a molded product such as an optical component obtained by molding the resin composition, and an optical pickup device which employs the optical component.

Abstract: The invention provides a protection cover of a pick-up head provided on a traverse of an optical drive. A plate flatly is positioned on an upper surface of the traverse, and the plate has a slot, with one end of the slot fastened to a spindle motor to clamp a disc and the other end of the slot forming a staying part for the pick-up head to stay in a stand-by mode. The pick-up head is disposed in the slot and has an objective lens. When the objective lens stays in the staying part out of a periphery of a 12-cm disc, the protection cover crosses over the staying part to protect the objective lens.

Abstract: Provided are an optical head device and an optical information recording/reproducing device, which can record/reproduce information to/from at least three kinds of optical recording media of different standards. A light beam emitted from a semiconductor laser is converged on a disk by an objective lens, and a reflected light beam from the disk is received by a photodetector. The optical system includes a liquid crystal refracting lens which can change the focal distance continuously within a predetermined range. The liquid crystal refracting lens has an electrode, and corrects, when the voltage applied to the electrode is changed, such a spherical aberration in the emitting light as changes with the kind of the disk. Moreover, a liquid crystal aperture control element has an electrode, and changes the effective numerical aperture of the objective lens in accordance with the kind of the disk, when the voltage applied to the electrode is changed.

Abstract: Plural grooves or lands formed in an information recording carrier include at least a wobbling region and data is recorded wobblingly in this wobbling region by frequency shift modulation while recorded digitally with a single or multiple waves as a channel bit.

Abstract: There is a need to provide correction of a temperature characteristic of an optical pickup of an optical disk recording/reproducing apparatus, in which items of the optical pickup including spherical aberration may be improved in temperature characteristic. To achieve the need, an optical disk drive is characterized by correcting a spherical aberration correction element when variation of a signal from the control circuit to the driver and/or a tracking or focusing error signal supplied to the controller has a value equal to or more than a predetermined value.

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: Disclosed herein are aspects of optical tape technology, tape manufacturing, and tape usage.

Abstract: An apparatus comprising: a processor for determining if a laser is operating in a single-mode state and for determining the degree to which one of one or more tunable parameters for the laser must be adjusted so that laser operates in a single-mode state if not operating in a single-mode state, wherein the one or more tunable parameters include the following parameters: the laser current and the wavelength of the output light. The apparatus may include a laser and/or a holographic storage medium. Also provided is a method for determining if a laser is operating in a single-mode state and for determining the degree to which one of one or more tunable parameters for the laser must be adjusted so that laser operates in a single-mode state if not operating in a single-mode state.

Abstract: An optical recording medium which includes three or more information layers and has a higher stack density of information layers than before in the direction of thickness while reducing crosstalk during reproduction, and a method for reading the optical recording medium are provided. The optical recording medium has a three-layer structure which includes a substrate, a first information layer, a first spacer layer, a second information layer, a second spacer layer, a third information layer, and a cover layer thinner than the substrate, with these layers being stacked in that order over the substrate, wherein the following Equation (I) is satisfied: (R2×R3×R2)/R1?0.0032 ??Equation (I) where R1 is the reflectivity of the first information layer, R2 is the reflectivity of the second information layer, and R3 is the reflectivity of the third information layer, and the first spacer layer and the second spacer layer are equal to each other in thickness.

Abstract: There are provided an optical disk device and tilt correction processing method for performing recording/reproduction by rapidly acquiring an optimal tilt correction value for an optical disk having a plurality of recording/reproducing layers. In an optical disk device capable of recording or reproducing information by irradiating a laser beam to each of a plurality of recording/reproducing layers of an optical disk, the tilt value is stepwise set within a predetermined range at a predetermined radius position of the recording/reproducing layer located at the farthest distance from the laser beam irradiation side so that an optimal tilt correction value can be obtained from the quadratic function by the method of least squares of the jitter or the like obtained from the disk. By applying the optimal tilt value obtained to the other recording/reproducing layer, it is possible to start recording or reproduction in a short time.

Abstract: A WORM-type recording layer in an optical information recording medium contains at least one azo-metal complex dye derived from a metal ion and a compound represented by the following general formula (1-1) or (1-2): wherein Q represents a carbocyclic group or a heterocyclic group, and R6 to R8 independently represent a hydrogen atom or a substituent. The compound represented by the general formula (1-1) or (1-2) has a dissociative hydrogen atom in Q, and the dissociative hydrogen atom in Q and the hydrogen atom in the —NH— group marked with asterisk * are eliminated from the compound, so that the residue is bonded to the metal ion to generate the azo-metal complex dye. The azo-metal complex dye may contain a component other than the metal ion and the compound represented by the general formula (1-1) or (1-2).

Abstract: The present invention discloses a servo system of an optical storage device, the optical storage device includes a pick-up unit for detecting signals reflected from an optical disc to generate a plurality of detecting signals, the servo system includes: a focus error signal generating module coupled to the pick-up unit for generating a plurality of focus error signals according to the detecting signals; a focus servo control module coupled to the focus error signal generating module for generating a focus control signal according to the focus error signals; and a focus actuator coupled to the focus servo control module and the pick-up unit for controlling the pick-up unit to adjust a focus position on the optical disc according to the focus control signal.

Abstract: A configurable photo detector circuit comprises a photo detector array including a plurality of photo detectors coupled to a plurality of amplifiers. A method for programming a detection pattern of the configurable photo detector circuit comprises selecting a first detection pattern for the photo detector array, generating first signals to create the first selected detection pattern, and applying the first generated signals to the photo detector circuit to implement the first selected detection pattern.

Abstract: An optical information recording apparatus includes a first optical system that radiates an information beam that carries information onto a recording medium; a second optical system that radiates reference beams onto the recording medium; a radiation position specifying unit that specifies a plurality of recording spots positioned within a radiation range of the reference beams; and an incident angle obtaining unit that specifies an incident angle of the reference beams that is used for recording an i'th interference fringe into a second recording spot adjacent to a first recording spot, as a value obtained by adding a product of 1/(1+m) and an absolute value of a difference between an incident angle of a first reference beam used for recording an i'th interference fringe into the first recording spot and an incident angle of a second reference beam used for recording an (i+1)'th interference fringe into the first recording spot.

Abstract: An objective lens actuator comprises, two objective lenses, each for focusing lights upon an optical disc, an objective lens holder member for holding the objective lenses thereon, and lens protectors for preventing the objective lenses from being contacted on the optical disc, wherein the lens protectors include first and second lens protectors, which are provided on both end portions of the objective lens holder member in a tracking direction, and a third lens protector, which is provided in a middle of the two objective lenses, wherein the first and second lens protectors, which are provided on both end portions of the objective lens holder member in the tracking direction, are provided the objective lenses and end portion of the objective lens holder member in the tracking direction, and the third lens protector, which is provided between the objective lenses, has a height closer to that of the optical disc than the protectors, which are provided on both end portions of the objective lens holder member in

Abstract: An optical-pickup apparatus comprising: a laser-light source including first-and-second-light-emitting points for laser lights with first-and-second wavelengths which points are disposed at positions deviating in a direction optically corresponding to an optical-disc-tracking direction; a diffraction grating including a plurality of periodic structures which are joined to be different in phase from each other in the direction and each of which includes a recess and projection repeated in a direction optically corresponding to an optical-disc-tangential direction, the diffraction grating being configured to generate main-and-sub-luminous fluxes from the laser light; a holder to hold the diffraction grating to be movable in the direction corresponding to the tracking direction; a collimating lens; an objective lens to focus the main-and-sub-luminous fluxes from the collimating lens on the same track of an optical disc; and a photodetector to be applied with reflected lights of the main-and-sub-luminous fluxes f

Abstract: In an information recording/reproducing device, a resting period (tm) is set to be constant regardless of a mark length of a recording mark and regardless of the number of divided recording pulses. Consequently, it is possible to provide an information recording device, an information recording method, and an information recording medium, each allowing formation of a recording mark with a uniform width by use of a low laser power and allowing reduction of the number of parameters for determining a recording waveform, when forming a long recording mark.

Abstract: A method is disclosed of reading an image data from an optical record carrier with a visually detectable pattern comprising a visually detectable pattern of pixels comprising at least one pattern element comprising an area of size s1 with a relatively low value v1 for an optical property and an area with size s2 with a relatively high value v2 for said optical property, wherein the data representative for a structure of the visually detectable pattern is embedded by variations in one or more of the parameters s1, v1, s2, v2 of the pattern elements. The method comprising the steps of scanning the visually detectable pattern and generating a detection signal representative for a visual property of the pattern as a function of position, retrieving the image data from the signal, retrieving an embedded data from the signal, generating an address data using said embedded data, storing image data values at addresses indicated by said address data.

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 objective lens actuator comprises a lens holder for attaching an objective lens thereon, a piece of focusing coil, being wound along side surface of the lens holder around the objective lens, and three magnets, being disposed opposing to two surfaces each having a normal line perpendicular to both a focusing direction and a tracking direction, among four side surfaces of the lens holder, wherein the three magnets are aligned, continuously, along the tracking direction, differing a polarity thereof from one another, and width of the magnets on both outsides is wider than width of the magnet inside, or alternately, one magnet, being disposed opposing to two surfaces each having a normal line perpendicular to both a focusing direction and a tracking direction, among four side surfaces of the lens holder, wherein the magnet is magnetized into three poles along the tracking direction, and among the three poles, width of the poles on both outsides is wider than width of the pole inside.

Abstract: It is an object of the present invention to achieve a recording medium more excellent in preservation resistance than conventional optical recording media. To achieve the above object, the present invention provides an optical recording medium comprising a substrate and a reflective layer, a first dielectric layer, a recording layer, a second dielectric layer and a light-transmission layer formed in this order on the substrate, the recording layer being decomposable by heat at a time of recording to achieve recording of the optical recording medium, wherein the optical recording medium further comprises a third dielectric layer between the second dielectric layer and the light-transmission layer.

Abstract: A method of applying image data as a visually detectable pattern with at least one embedded data element at an optical record carrier is disclosed, comprising the step of physically mapping at least one channel symbol onto the record carrier, the channel symbol being selected from a set of mutually different channel symbols, the channel symbols each comprising an area of size s1 with a relatively low value v1 for an optical property and an area with size s2 with a relatively high value v2 for said optical property, the channel symbols being distributed over a plurality of subsets each having a plurality of channel symbols wherein the plurality of channel symbols within a subset have a distance that is substantially less than the distance between channel symbols of mutually different subsets, wherein the distance between two channel symbols is defined as the absolute difference between the ratios s1/(s1+s2).

Abstract: An ultraviolet-curable composition of the present invention, which is used for a light transmission layer of an optical disk, includes a urethane (meth)acrylate having an isocyanate structure; and at least one of a monofunctional (meth)acrylate and a difunctional (meth)acrylate, wherein the combined amount of the urethane (meth)acrylate, the monofunctional (meth)acrylate and the difunctional (meth)acrylate is at least 90% by mass of the ultraviolet-curable composition. This ultraviolet-curable composition for a light transmission layer is able to realize an optical disk that exhibits excellent durability even under conditions of high temperature and high humidity, minimal decrease in light reflectance, and excellent adhesion between layers.

Abstract: The present invention relates to an optical holographic device and a corresponding method for reading out a data page recorded in a holographic recording medium (106). In order to improve the bit error rate a reconstruction means (115) provided for reconstructing a dark and a light image from a separate checkerboard page comprising a pattern of dark and light pixels or from the detected imaged data page, and an image correction means (116) is provided for correcting said detected imaged data page by gain compensation using said reconstructed dark and light images.

Abstract: The present invention is to provide a method for treating an optical recording medium including irradiating a recording layer, which has recorded information, with a treatment light through a light diffusion member having a haze of 70% to 100%, wherein the optical recording medium contains at least the recording layer which records information using holography, and a device for treating an optical recording medium containing a light source for the treatment light, and the light diffusion member having a haze of 70% to 100% and disposed between the light source and the optical recording medium, wherein the recording layer is irradiated with the treatment light through the light diffusion member from the light source. The preferred aspects are that a half width of wavelength for an energy intensity of the treatment light is 5 nm to 700 nm; and the optical recording medium is a write-once read-many optical recording medium.

Abstract: The invention relates to a method and a device for producing a hologram in an optical medium, particularly for storing data in the optical medium. In the method, the hologram is produced in the optical medium using laser beams, wherein the laser beams are formed from a laser beam emitted by a free-running semiconductor laser, are directed onto the optical medium, optionally contradirectionally, and at least partially spatially overlap in the optical medium. For producing holograms using inexpensive components with a high contrast, the invention provides for arranging the reflection unit (15) such that the optical path length (?x) between the focus of the laser beam in the storage medium (10) and the reflecting surface of the reflection unit (15) satisfies the condition ?x=0.5*?s*a in the region of the optical axis, wherein a is a natural number greater than or equal to 1 and ?s is a distance between neighboring coherence centers of the laser beam produced by the semiconductor laser (16).

Abstract: It is an object of the present invention to provide an optical recording medium containing a laminated structure of a first deformable material layer containing a phase-change material that absorbs light at a recording wavelength to generate heat and is subject to exothermic melting and deformation and a second deformable material layer containing a material which contains a silicon oxide (SiOx; 0<x?2) that transmits light and is subject to thermal deformation and alteration. After information is recorded, the thickness of the first deformable material layer is changed according to the recorded information making center of the recorded marks thicker than the ends and the second deformable material layer is deformed and altered corresponding to the concave-convex-pattern formed on the first deformable material layer based on the recorded information and when the information is reproduced, the first deformable material layer is altered from solid to molten state.

Abstract: An optical pickup (10) includes a light emitting element (11), a holding member (14), a light receiving element (18), and a base (13). The holding member (14) is fixed to the base (13) by a combined bonding portion (17). The combined bonding portion (17) is sandwiched between the holding member (14) and the base (13) so as to fix the holding member (14) to the base (13). The combined bonding portion (17) includes a first bonding portion (15) composed of a first adhesive and a second bonding portion (16) composed of a second adhesive having a higher curing shrinkage rate than the first adhesive. The first bonding portion (15) and the second bonding portion (16) are each sandwiched between the holding member (14) and the base (13), and the second bonding portion (16) is provided to cover at least a part of an outer peripheral surface of the first bonding portion (15). A difference between the curing shrinkage rate of the first adhesive and that of the second adhesive is 3.0% or less.

Abstract: Semiconductor lasers emit lights having wavelengths of about 400 nm, 650 nm, and 780 nm, respectively. A transmittance adjustment element is provided in an optical path of the light reflected from a disk. The transmittance adjustment element includes a first optical thin film that changes transmittance of a 650-nm-wavelength light relatively to transmittance of 400-nm- and 780-nm-wavelength lights, and a second optical thin film that changes transmittance of a 780-nm-wavelength light relatively to transmittance of 400-nm- and 650-nm-wavelength lights. The transmittance adjustment element has the function of maintaining constant the intensity of light incident onto a photodetector irrespective of the type of medium.

Abstract: An optical information recording and reproducing apparatus for recording information on a recording medium by forming interference fringes generated by interference between an information beam and a reference beam on the recording medium and for reproducing the information by irradiating, with the reference beam, the recording medium, in which the interference fringes are formed. The apparatus includes a spatial light modulator for spatially modulating at least a portion of a light beam emitted from a light source into the information beam. A light sensing device reads the information beam extracted from the recording medium by the reference beam irradiated on the recording medium.

Abstract: In the optical pickup device, while reflection light reflected from the optical multi-layer disc is divided into a plurality of regions so as to produce a plurality of divided optical beams, the divided optical beams are focused onto different positions on a photodetector, and a focus error signal is detected by employing a plurality of the divided optical beams by utilizing the knife edge method, and further, a tracking error signal is detected by employing a plurality of the divided optical beams. Furthermore, the dividing regions of the optical beam and light receiving parts are arranged in such a manner that stray light derived from other layers of the optical disc is not entered to a servo signal-purpose light receiving part of the photodetector when the divided optical beam is focused onto a target layer of the optical disc.

Abstract: A lens driving apparatus installed into an optical unit, includes a lead screw rotated by a rotation of a motor, a lens holder moved reciprocally along a rotation axis line of the lead screw by a rotation of the lead screw, a guide shaft extended in parallel with the rotation axis line, and passing through the lens holder to guide, and a lens held at a free end of the lens holder in a cantilever state.

Abstract: The optical storage medium comprises a read-only region with a substrate layer, an data layer, and a mask layer with a phase change material for providing a super resolution near field effect, which layers are arranged as a stack of layers, and a recordable region comprising a layer with a tracking structure for providing a tracking information. The tracking structure is covered by the mask layer for using the mask layer as the data layer of the recordable region. The optical storage medium is in particular an optical disc and the recordable region a reserved area and/or an inner area of the optical disc. The apparatus for recording and/or reading data from the optical disc comprises a pickup unit providing a laser beam for reading data from the read-only region with the super resolution near-field layer of the optical storage medium, and uses this laser beam for recording and/or reading data on the data layer of the recordable region.

Abstract: To obtain optimum conditions for writing data on the disc. Provided is an optical disc drive for writing/reading data on/from a loaded optical disc medium comprising: a pickup for writing/reading data on/from the optical disc medium using laser light; and a controller for controlling an operation of the optical disc drive. The controller judges whether the loaded optical disc medium is unrecorded; records a first piece of data on a test area of the optical disc medium in a case where the loaded optical disc medium is judged to be unrecorded; determines optimum output power for recording the data by reproducing the first piece of data; records a second piece of data on the test write area using the determined optimum output power; and adjusts focus balance by reproducing the second piece of data.

Abstract: An optical information recording/reproducing apparatus includes a spatial light modulator that converts an irradiation beam emitted from a light source to a single information beam that carries information; an optical system that causes the single information beam to be collected on an optical-information recording medium including an information recording layer capable of recording the information as hologram by using interference fringes produced due to interference between the single information beam and a plurality of reference beams, and causes each of the reference beams to be irradiated to the optical-information recording medium from mutually different directions so as to intersect with the single information beam in the information recording layer; and a controller that controls to cause the light source to emit the irradiation beam and performs angular multiplexing recording of the information in the information recording layer while controlling to drive either one of the optical-information recordi

Abstract: An optical phase controller includes an optical phase control element so that a phase of incident light applied to the optical phase control element is controlled. The optical phase control element includes a metal structure having anisotropy in a first direction and a second direction perpendicular to the first direction within an electric-field vibration plane of the incident light, the wavelength of the incident light includes a plasmon resonance wavelength possessed by the metal structure, and the incident light is linearly polarized light or elliptically polarized light simultaneously having polarized components in the first direction and the second direction perpendicular to the first direction.

Abstract: A laser driving device includes a storage unit that stores signal patterns for recording-waveform control representing level information of each divided driving signal to drive a laser device on a space and a mark based on the divided driving signals. Also, it includes a pulse generator that generates the reference pulse and the switching pulse based on a first transmission signal and a second transmission signal. The first transmission signal contains timing information for acquiring a reference pulse that represents a timing of repetitively switching between the space and the mark. The second transmission signal contains timing information for acquiring a switch pulse that represents a timing of switching the signals. Among level information for each of the signals in the storage, reference level information is read together with the reference pulse. Other level information after the reference level information is sequentially read for each switching pulse.

Abstract: A hologram recording and reproducing device controls an optical beam output from an external cavity semiconductor laser to improve a diffraction efficiency. The hologram recording and reproducing device includes an external cavity laser, a photodiode, a laser drive circuit and a laser diode controller. The external cavity laser has a laser diode adapted to emit an optical beam that is used to generate data light and reference light with which a hologram recording medium is irradiated. The photodiode detects the amount of the optical beam output from the external cavity laser. The laser drive circuit supplies a current to the external cavity laser. The laser diode controller controls the laser drive circuit to ensure that a value obtained by integrating the detected intensity of the optical beam with respect to time over a predetermined period is equal to predetermined recording energy.

Abstract: An objective lens used for an optical pickup device wherein the optical pickup device includes: light source; and a converging optical system including the objective lens for converging a light beam emitted from the light source to an information recording surface of an optical information recording medium, and the optical pickup device is capable of recording and/or reproducing information by converging the light beam emitted from the light source to the information recording surface of the optical information recording medium with the converging optical system, the objective lens being a plastic single lens and satisfying following formulas when NA is an image-side numerical aperture required for recording and/or reproducing information to the optical information recording medium and f (mm) is a focal length of the objective lens.

Abstract: An optical disc apparatus can highly accurately record a hologram representing information on or reproduce such a hologram from an optical disc. When recording information on an optical disc 100, the optical disc apparatus controls the position of an objective lens OL1 according to the outcome of detection of a red reflected light beam Lr2 so as to make the focus Fr thereof follow a target track and it also makes the focus Fb1 of a blue light beam Lb1 agree with a target mark position by the objective lens OL1 and also the focus Fb2 agree with the target mark position by controlling the position of another objective lens OL2 according to the outcome of detection of the blue light beam Lb1 by way of the objective lenses OL1 and OL2 so as to make the focus Fb1 of the blue light beam Lb1 and the focus Fb2 of the blue light beam Lb2 agree with the target mark position and the blue light beam Lb1 and the blue light beam Lb2 interfere with each other.

Abstract: An optical information recording medium of the present invention includes at least a recording layer (4) that allows information to be recorded thereon and/or reproduced therefrom by being irradiated with a laser beam, and a transmittance adjusting layer (7) in this order from an incident side of the laser beam (30). In the optical information recording medium of the present invention, the transmittance adjusting layer (7) contains Bi, Ti, and O and with a composition of Bi, Ti, and O contained in the transmittance adjusting layer (7) being denoted as BixTiyOz, in atomic number ratio, x, y, and z satisfy 0.07?x?0.35, 0.07?y?0.28, 0.56?z?0.70, and x+y+z=1. Or the transmittance adjusting layer (7) contains Bi2O3 and TiO2, and with a composition of Bi2O3 and TiO2 contained in the transmittance adjusting layer (7) being denoted as (Bi2O3)?(TiO2)?, in molar ratio, ? and ? satisfy 0.2???0.7, 0.3???0.

Abstract: A signal processing device for optical disks includes a reflected light process section configured to convert reflected light received by an optical pickup into an electric signal based on a first gain, wherein the optical pickup emits laser light to an optical disk and receives reflected light from the optical disk; a servo signal generation section configured to generate a servo signal by using the electric signal generated by the reflected light process section; a servo signal control section configured to control the servo signal so that a change in the amplitude of the servo signal, in response to an increase or decrease of the amount of the reflected light from the optical disk, is suppressed using an attenuator that attenuates the servo signal generated by the servo signal generation section by a factor of a second gain; and a gain setting section configured to set the first gain to the reflected light process section and the second gain to the servo signal control section substantially simultaneously.

Abstract: A fabrication method of a multilayer optical recording medium having a plurality of recording layers, comprises a step of preparing an optical recording medium having at least one record area; a write-position mark generating step of recording write-position marks in the record area beforehand; a step of preparing an optical system including a common objective lens to focus a data recording beam and a position mark recording beam on different positions in a thickness direction of the record area; a first data writing step of writing data between the write-position marks with following the write-position marks by the data recording beam; a position mark recording step of, in parallel with the first data writing step, recording new write-position marks in the record area by the position mark recording beam; and a second data writing step of writing data between the new write-position marks with following the new write-position marks by the data recording beam.

Abstract: An optical information recording medium includes a recording layer in which a track is formed, the track having recording marks linearly arranged thereon. Each recording mark has a dimension corresponding to a reference mark length, which serves as a reference, in a track direction along which the track extends, the dimension being smaller than dimensions of the recording mark in two directions perpendicular to the track direction.