Abstract: A reproduction signal evaluation method evaluates the quality of a reproduction signal reproduced from an information recording medium based on a binary signal generated from the reproduction signal using a PRML signal processing system. A pattern extraction step extracts, from the binary signal, a specific state transition pattern which has the possibility of causing a bit error; a step computes a differential metric based on the binary signal; an extraction step extracts the differential metric which is not greater than a predetermined signal processing threshold; a step determines a mean value of the differential metrics which are not greater than the signal processing threshold and extracted in the extraction step; a standard deviation computing step determines a standard deviation which corresponds to an error rate predicted from the mean value; and an evaluation step evaluates a quality of the reproduction signal using the standard deviation.

Abstract: An optical disk reproducing device for controlling false detection of synchronization signals due to intersymbol interference, and stably improving accuracy of frequency acquisition of a phase locked loop (PLL) even when offset and so on occur. A signal width close to an original mark length is obtained to use for frequency acquisition of the PLL by, for example, using two different slice thresholds and taking a width between a rising of a result of slicing at one threshold and a falling of a result of slicing at the other threshold as a synchronization signal width. When asymmetric properties due to offset, asymmetry, etc. occur, an amount of corrections on the slice threshold is calculated, and it is reflected on a threshold previously set to always obtain a correct synchronization signal width.

Abstract: A power saving method and a power saving system are applied in an optical disk drive. The power saving system comprises a power controlling unit for differentiating the specific sets of circuits not being used at a specific operation rate and powering them down. The sets of circuits not being used will be powered up while the associated operation rate at which they are required to operate is nearly started.

Abstract: A recording medium includes a photosensitive layer, a nonphotosensitive layer, and a recording layer formation region in which the photosensitive layer and the nonphotosensitive layer are laminated. The photosensitive layer includes a recording layer in which interference fringes formed in parallel with a recording medium surface are deleted or changed within a portion irradiated with focused light to record information or light reflected during irradiation of focused light is used to reproduce information.

Abstract: Provided is an objective lens that allows securing of a long working distance for a laser beam with a long wavelength and has a predetermined thickness or larger, and an optical pickup apparatus including the objective lens. In an objective lens of the present invention, a first region that focuses laser beams of a BD, DVD, and CD standards, a second region that focuses the laser beams of the DVD and CD standards, and a third region that focuses the laser beams of the BD and the DVD standards are provided in this order from a center portion of the objective lens. An optical super resolution with the laser beam of the BD standard is achieved by preventing a portion of the laser beam of the BD standard transmitted through the second region from contributing to spot formation.

Abstract: An optical head device includes a light blocking region (7y) which is disposed on a light flux of a reflected light beam resulting from reflection by a recording layer on which a blue light beam is focused, and blocks, when there are at least two recording layers on a blue light beam incident side of the recording layer on which the blue light beam is focused or on a side thereof opposite to the blue light beam incident side, reflected light beams resulting from reflection by the at least two recording layers which are incident on a region in a photodetector (9) where the reflected light beams resulting from the reflection by the at least two recording layers interfere with each other. The light blocking region (7y) is not formed on an optical axis of the reflected light beam resulting from the reflection by the recording layer on which the blue light beam is focused. This configuration allows an improvement in the S/N ratio of a signal outputted from the photodetector.

Abstract: Techniques are provided for increasing storage capacity in a holographic storage system. While typical holographic storage systems involve binary storage for each data position in a holographic disk, present techniques involve storing data such that more than two data levels may be recorded in each data position. In some embodiments, a recording beam directed to the disk may be adjusted to different power levels depending on the data level to be recorded. Furthermore, the recording time at a data position may be adjusted to increase the energy directed to the data position by increasing the amount of time the recording beam is impinged on the data position. Embodiments are suitable for different types of holographic storage, including dye-based medium.

Abstract: Techniques are provided for controlling the reading of micro-holograms from a holographic disk based on a target data layer to be read in the disk. Reading a target data layer which is relatively deeper in the disk (e.g., farther from an optical head emitting a reading beam) may involve using a higher power reading beam to compensate for power attenuation of the returned reading beam. For example, a power adjustment module may be used to dynamically adjust a reading laser emitting the reading beam, based on the dynamically changing target data layer. By compensating for power attenuation in deeper target data layers, the variance of power in the returned reading beams may be decreased, possibly improving the bit error rate in micro-hologram reading techniques.

Abstract: Methods and systems are provided for recording micro-holograms in a holographic disk. Disk tilting or disk imperfections may cause counter-propagating recording and reference beams to deviate from the target data position in the disk. In some embodiments, a tracking beam is directed to a tracking position in the disk, and deviation of the tracking beam from the tracking position may indicate tracking and/or focusing errors of the recording and/or reference beams. A detector may generate an error signal in response to such errors. A first servo-mechanical system may actuate a first optical head (e.g., transmitting the reference and tracking beams) to compensate for such errors, and a second servo-mechanical system may actuate a second optical head (e.g., transmitting the recording beam) to follow the actuation of the first servo system, such that an interference of the reference beam and the recording beam may be maintained in the target data position.

Abstract: An optical disc has a data layer including a data-layer substrate made of a transparent material and a data-layer reflection film formed on an upper side of the data-layer substrate, a display layer including a display-layer substrate having a display pattern and a display-layer reflection film formed on a lower side of the display-layer substrate, and an intermediate layer made of a transparent material provided between an upper side of the data layer and a lower side of the display layer. The data- and display-layer reflection films exhibit specific reflectivity to allow the display pattern to be visible from a lower side of the data-layer substrate through the data-layer reflection film.

Abstract: An optical system for optical pickup includes a magnification conversion optical element moving along an optical axis direction in accordance with each recording surface and an objective lens element converging a light beam incident through the magnification conversion optical element, to form a spot on a corresponding recording surface of the recording surfaces, and satisfies the following formula. 4.0×10?4<Mn/(tn?tc)×f<6.0×10?4??(1) Here tc is the thickness [?m] of the base plate at which a third-order spherical aberration which occurs when a parallel light beam is incident on the objective lens element is the minimum, f is the focal length [mm] of the objective lens element, and Mn is the imaging magnification of the objective lens element when a spot is formed through the base plate having a thickness to [?m].

Abstract: An objective lens element which can obtain appropriate spot performance only by simple position adjustment, and an optical pickup device using the objective lens element are provided. In the objective lens element, an amount of a generated third-order astigmatism of a spot which is formed when symmetry axes of optically functional surfaces are located parallel to the normal line of a base plate and an incident light beam incident such that a central light beam thereof is tilted at 0.5 degree with respect to the normal line of the base plate is converged, is reduced to be less than an amount of a generated spherical aberration of a spot which is formed when the symmetry axes of the optically functional surface are located parallel to the normal line of the base plate and an incident light beam incident parallel to the normal line of the base plate is converged.

Abstract: A high-NA and thin objective lens which prevents occurrence of a crack during lens molding and can stably be molded is provided. The present invention is directed to an objective lens having an optical surface having power which is not negative. The objective lens is a single lens and is formed such that a flat portion which is provided at an outer peripheral portion and perpendicular to the optical axis is closer to a disc surface than the position of the top of an exit-side surface of the objective lens and such that the rate of change in sag of the exit-side surface is continuous across the entire region.

Abstract: An optical data storage medium is provided. The optical data storage medium includes a polymer matrix; a reactant capable of undergoing a change upon triplet excitation, thereby causing a refractive index change; and a non-linear sensitizer capable of absorbing actinic radiation to cause upper triplet energy transfer to said reactant. The refractive index change capacity of the medium is at least about 0.005. The non-linear sensitizer comprises a triarylmethane dye.

Abstract: A vertical cavity surface emitting laser includes a semiconductor substrate, a first semiconductor multilayer film reflector of a first conductivity type laminated on the semiconductor substrate, a resonator, and a second semiconductor multilayer film reflector of a second conductivity type laminated on the resonator. In each of the first and second semiconductor multilayer film reflectors, a pair of a high-refractive-index layer and a low-refractive-index layer is stacked. The resonator includes an active layer laminated on the first semiconductor multilayer film reflector. The resonator includes a pair of spacer layers and a resonator extending region. A composition of at least a layer included in the resonator extending region is different from any of compositions of the semiconductor substrate, the first semiconductor multilayer film reflector, and the second semiconductor multilayer film reflector.

Abstract: A signal processing apparatus for an optical disc with a first type region and a second type region is disclosed. The signal processing apparatus comprises: a determining unit, arranged to determine that an input signal is a first type input signal derived from the first type region or a second type input signal derived from the second type region; a peak-bottom detector, arranged to detect a peak-bottom value of the input signal; and a control circuit arranged to determine that the peak-bottom value is derived from the first type input signal or the second type input signal according to a determining result from the determining unit.

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

Abstract: A recording and reproducing area and a reproduction-only area are formed by wobbling a groove formed in a spiral fashion to form a track to be tracked on a disk. The recording and reproducing area has address information recorded by wobbling of the groove and information recorded and reproduced by phase change marks on the track formed by the groove where the address information is recorded. The reproduction-only area has prerecorded information recorded by wobbling of the groove.

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

Abstract: A method for detecting whether vertical deviation of an optical disc occurs is provided. First, before a pickup head is successfully focused on the optical disc, a pickup head is actuated based on an input control signal so as to generate a focus error signal with a plurality of S-curves. Then, a plurality of zero crossing points of the S-curves in the focus error signal is identified and a plurality of input control values respectively corresponding to the zero crossing points is obtained. A variation of the input control values is then calculated. Whether vertical deviation of the optical disc occurs can be determined according to the variation of the input control values.

Abstract: A circuit for generating a tracking error signal is provided. The circuit includes a digitizing circuit, a short signal removing circuit and phase comparator. The digitizing circuit receives first and second pick-up signals outputted from a pick-up head, and respectively compares the first and the second pick-up signals with a reference signal to obtain a first digital signal and a second digital signal. The short signal removing circuit is used for removing pulses in the first and the second digital signals, wherein the pulse width of the removed pulses are shorter than a preset time, and the first and second digital without the removed pulses are respectively served as a first determining signal and a second determining signal. The phase comparator receives the first determining signal and the second determining signal for outputting the tracking error signal according to a phase difference between the first and the second determining signals.

Abstract: Various embodiments of the present invention provide systems and methods for data processing. As an example, a pattern detection circuit is discussed that includes a distance calculation circuit and a comparator circuit. The distance calculation circuit is operable to calculate a noise whitened distance between a reference signal and a received input to yield a comparison value. The comparator circuit is operable to compare the comparison value with a threshold value.

Abstract: An information carrier for holding user information includes access information for accessing the user information, the access information being stored in a pre-determined first region on the information carrier. The information carrier further includes at least one further region different from the first region, the further region comprising dummy information.

Abstract: An optical information storage medium system is provided. The optical information storage medium system includes an optical pickup, which comprises a photo-detector configured to control light power detected by receiving a portion of light emitted from a light source and obtains an output signal proportional to output light power of the light source from a signal detected by the photo-detector, and a signal processor configured to signal-process the output signal input from the optical pickup. The signal processor includes a sensitivity acquisition unit configured to acquire a sensitivity value of the photo-detector, a gain calculator configured to calculate a target gain value to be used in comparing the sensitivity value of the photo-detector, which is acquired by the sensitivity acquisition unit, with a target sensitivity value to be used by the optical information storage medium system, and a gain adjustment unit.

Abstract: Shape-wise thicknesses tr1, tr2, . . . , and trN of a cover layer and first through (N?1)-th intermediate layers of an optical recording medium having refractive indexes nr1, nr2, . . . , and nrN are converted into thicknesses t1, t2, . . . , and tN which are calculated by products of a function f(n)=?1.088n3+6.1027n2?12.042n+9.1007, where n=nr1, nr2, . . . , and nrN.

Abstract: The present invention provides an optical disc drive and a method for changing a mode in the same. In an embodiment of the present invention, it can be determined whether to change a mode of the optical disc drive based on a command sent from a host connected through an interface. If a predetermined command is sent from the host within a predetermined time after the optical disc drive is newly connected to the host or power is supplied to the optical disc drive while the optical disc drive is already connected to the host, the mode may be switched into a first mode of connecting to a computer, and otherwise the mode may be switched into a second mode of connecting to a host with a function of playing data of a medium connected through the interface. Accordingly, the optical disc drive can automatically change its operation mode.

Abstract: An ultraviolet curable composition having, a coating film cured with ultraviolet rays with a large number of crosslinking points due to a (meth)acrylate compound that does not intramolecularly have a cyclic moiety and has a functionality of three or more and, the compound does not intramolecularly have a cyclic moiety, plastic deformation due to a cyclic moiety is less likely to occur. Additionally, a monofunctional (meth)acrylate compound forms a homopolymer having a glass transition temperature of 20° C. or less, has a low glass transition temperature, and is flexible. Curing contraction caused in ultraviolet curing is suppressed and plastic deformation is less likely in the resultant cured film at room temperature. An optical disc employing the above ultraviolet curable resin composition reduces warpage; and rapid recovery from deformation caused even by application of a load for a long period of time or as a result of an impact due to falling.

Abstract: The present techniques provide techniques for outputting counter-propagating parallel light waves to pre-record a holographic data disk. The parallel light waves are transmitted through a holographic system via a fiber optic bundle including a plurality of polarization-maintaining (PM) optical fibers. Each of the PM optical fibers in the fiber optic bundle may have one or more of a different wavelength, a different coherence length, and a different polarization orientation to reduce crosstalk in the disk. Furthermore, the fiber optic bundle array is rotated to produce interference spots indicative of micro-holograms according to the data track pitch of the holographic disk over which the fiber optic bundle is outputting the light waves.

Abstract: The present techniques provide methods and systems for recording micro-holograms on a holographic disk using a plurality of counter-propagating light beams in parallel. The parallel counter-propagating light beams overlap to form interference patterns on a data layer and over multiple data tracks in the holographic disk. Rotating the disk enables the parallel recording of micro-holograms over multiple data tracks, thus reducing recording time. Further, the illumination pattern may include illuminated spots and non-illuminated regions, such that each illumination spot may cover a relatively small fraction of the data layer plane, possibly controlling the depth spread of the recorded micro-hologram. In some embodiments, data in the parallel signal beams may be retrieved from a master holographic disk or may be modulated into the parallel signal beams.

Abstract: A wobble signal extracting circuit includes: a readout signal generating circuit generating an RF signal by adding first and second detection signals corresponding to reflected light from inside and outside a recording track; a first subtractor generating a push-pull signal by subtracting the first and second detection signals, respectively; a first analog-to-digital converter (ADC) converting the RF signal to digital; a second ADC converting the push-pull signal to digital; a residual RF component generating circuit generating a residual RF signal component equivalent to the RF signal component remaining in the digitized push-pull signal; and a second subtractor generating the wobble signal by subtracting the residual RF signal component from the digitized push-pull signal. The residual RF component generating circuit generates the residual RF signal component so that it may approach the remaining RF signal component based on correlation between the wobble signal and the digitized RF signal.

Abstract: An optical pickup includes a light source, an optical system for irradiating a recording medium including a plurality of recording layers with light from the light source, a diffraction optical element that divides light reflected from the recording medium into a plurality of optical fluxes and diffracts the fluxes, and an optical detector receiving the optical flux diffracted by the diffraction optical element. The optical detector includes a light receiving element detecting a focus error signal, wherein a longitudinal direction of the light receiving element is arranged to coincide with a circumferential direction of the recording medium, or arranged to be inclined to a circumferential or radial direction.

Abstract: A reproducing device includes a homodyne detection part that carries out homodyne detection by using reflected light of first light obtained from a recording layer as signal light and using reflected light of second light by a mirror as reference light, a signal reproducing part that obtains a reproduced signal based on the signal light, based on a result of homodyne detection, and a one-axis actuator that drives the mirror. The reproducing device further includes an optical path length servo control part that carries out driving control of the one-axis actuator in such a manner that the optical path length difference between the signal light and the reference light is kept constant, and an offset giving part that gives an offset that reduces or enlarges the amplitude difference of the reproduced signal of marks that are recorded in the recording layer and have sizes different from each other.

Abstract: An optical recording medium drive device including: a combining prism for combining a recording first laser beam emitted from a first light source with a recording second laser beam emitted from the first light source so as to coaxially guide them; an objective lens for condensing the first and second laser beams from the combining prism toward an optical recording medium; a first photodetecting means for detecting reflected light of the first laser beam from a recording layer; a second photodetecting means for detecting reflected light of the second laser beam from a guide layer; a magnification conversion element disposed on an optical path of the second laser beam between a second light source and the combining prism for diffusing or converging the second laser beam incident upon the objective lens; a first focus error generating means for generating a first focus error signal indicating an error between a condensed spot position of the first laser beam and the recording layer based on an output signal of

Abstract: In an optical pickup apparatus, a major part of an optical path of a laser beam emitted from a first semiconductor laser device and an optical path of a laser beam emitted from a second semiconductor laser device 3 are shared. The first laser beam is transmitted through a quarter wavelength plate and a second reflecting mirror and is reflected by a first reflecting mirror. With this structure, the number of parts of optical systems disposed in the optical pickup apparatus is reduced, an attachment operation of the parts becomes easier, and a time required for adjusting an optical axis is reduced. Thus, an operational efficiency is greatly improved.

Abstract: A recording apparatus for recording information on an optical recording medium includes a mode-locked laser unit that includes a semiconductor laser emitting a laser beam for recording the information on the optical recording medium, and an external resonator, an optical modulation unit that amplifies and modulates the laser beam emitted from the mode-locked laser unit, a recording signal generation unit that generates a recording signal based on a reference signal from a drive of the optical recording medium, and a modulation unit that generates a modulation signal for driving the optical modulation unit by latching the recording signal using a laser clock generated by an oscillation pulse of the laser beam emitted from the mode-locked laser unit.

Abstract: The present invention provides an object lens actuator in which a tilt of an object lens due to a change of an ambient temperature is inhibited even when a metal member is attached to a resin based securing part. It is desirable to improve quality of writing and playing in a disc drive using the object lens actuator. This is achieved by coupling a metal member having a flat portion and bent portions to a securing part near top ends of the bent portions. The flat portion has a normal in the focusing direction. The bent portions extend in the focusing direction from the respective ends of the flat portion in the tracking direction. The securing part has an opening therethrough in the focusing direction, and in the opening, the metal member and the securing part may be coupled between each outermost two support members in the focusing direction.

Abstract: An objective lens includes: a solid immersion lens having a super-hemispherical or hemispherical shape, wherein a hyper-lens portion is formed in a part of an object-side surface of the solid immersion lens and integrated therewith by alternately stacking a first thin film having a positive dielectric constant and a second thin film having a negative dielectric constant along spherical shapes starting from a spherical shape having a radius Ri around a predetermined reference point Pr set outside the object-side surface of the solid immersion lens to a spherical surface having a radius Ro (Ro>Ri) around the reference point Pr.

Abstract: A discrimination method of an optical disc. The method includes: focusing a light spot on a rewritable zone of the optical disc; reading an EFM signal of data marks of the optical disc to check if the optical disc is a data disc or a blank disc; when the optical disc is a data disc, utilizing an SBAD signal for discrimination of the optical disc; when the optical disc is a blank disc, utilizing a DPD signal for discrimination of the optical disc; checking if the header signals exist or not; identifying the optical disc as a DVD-RAM disc if the header signals exist; and identifying the optical disc as a DVD-RW disc if there is no header signal. In this way, the accuracy of the optical disc discrimination is enhanced.

Abstract: An apparatus includes a planar waveguide having a core layer and a cladding layer adjacent to the core layer, the waveguide being shaped to direct light to a focal point; a magnetic pole adjacent to the cladding layer; and a near-field transducer positioned adjacent to the focal point, wherein the near-field transducer includes an enlarged portion and a peg having a first end positioned adjacent to an end of the waveguide and a second end positioned adjacent to a side of the enlarged portion. A data storage device that includes the apparatus is also provided.

Abstract: An optical disc device includes: a focus error signal generation section configured to generate a focus error signal based on reflected light from an optical disc; and a focus control section configured to generate a drive signal for focus control of an optical pickup from the focus error signal. The focus control section includes a filter adjustment portion configured to activate a filter adjustment signal when the absolute value of the focus error signal is equal to or more than an error threshold, a proportional term computing unit, an integral term computing unit configured to multiply the focus error signal by an integral gain and integrate the multiplied result, a differential term computing unit, and an adder configured to add up results of these computing units to be output as the drive signal. The integral term computing unit decreases the integral gain when the filter adjustment signal is active.

Abstract: A method for processing information is provided. The method includes directing a laser beam to a first track of a first layer of a holographic storage medium. The method also includes recording a base voltage based on a look-up table. The method includes directing the laser beam to a target track in the first layer, based on position information in tracks. Further, the method includes recording an offset voltage for the target track into the look-up table. Still further, the method includes directing the laser beam to a target layer based on position information in vertical wobbles. The method also includes recording an offset voltage for the target layer into the look-up table. Finally, the method includes determining a final voltage based on the look-up table and applying the final voltage to an actuator for moving the laser beam to a final target position in the holographic storage medium for recording and retrieval of information.

Abstract: A spherical aberration compensation method is provided. A first thickness of a cover layer at a first radius position of an optical disc is measured. A second thickness of the cover layer at a second radius position of the optical disc is measured. A spherical aberration calibration is performed at a third radius position of the optical disc to obtain an optimal spherical aberration compensation value. According to the first and second radius positions, the first and second thicknesses, and the optimal spherical aberration compensation value at the third radius position, a spherical aberration compensation formula is acquired. Afterwards, an updated spherical aberration compensation value is calculated by the spherical aberration compensation formula according to a fourth radius position where an optical pickup head of the optical disc drive is located. The updated spherical aberration compensation value is inputted into a spherical aberration compensator of the optical disc drive.

Abstract: A disc player with light-sensing type loading mechanism includes a casing, a control board, a slide mechanism and a light-sensing element. The light-sensing element is adopted to serve as a switch controlling the slide mechanism to reciprocate between a loading area and a reading area. The disc to be loaded is detected by an optical manner instead of physical. The invention may increase durability of a disc player.

Abstract: The present invention provides systems of recording holograms that reduce the writing time, increase the diffraction efficiency, improve the resolution, or restitute color. These systems are well suited for use with an updateable 3D holographic display using integral holography and photorefractive polymer.

Abstract: Systems, methods, and machine-readable media provide device-level functionality without altering device memory. A non-transitory machine-readable medium can store a first set of instructions that are executed by the machine to provide device-level functionality unsupported by a second set of instructions stored in device memory associated with the machine without altering the second set of instructions stored in the device memory. For example, the machine can be an optical disc player and the medium can be an optical disc.

Abstract: A recording device includes a light irradiation portion which irradiates an optical recording medium with laser light emitted from a light source via a field lens, a light emission drive portion which drives and causes the light source to emit light, a front monitor which receives the laser light emitted from the light source, a light receiving portion which receives reflected light which is obtained from the optical recording medium in response to the laser light irradiation, a focus servo control portion which controls a focus servo of the field lens on the basis of a light receiving signal by the light receiving portion, a surface jump controller which controls the focus servo control portion so as to perform a focus jump operation to a surface of the optical recording medium, and a surface APC corrector which performs a process as an auto power control (APC) correction process.

Abstract: The present invention provides an electronic equipment which includes an optical member including a first adhesive application portion, wherein a support member is provided in which a second adhesive application portion is provided on a support surface of the optical member, a cross-sectional surface of the first adhesive application portion is opposite to a cross-sectional surface of the second adhesive application portion, a separation portion is provided between the first cross-sectional surface and the second cross-sectional surface, and a approximately spherical adhesive is fixed around an approximately center of the separation portion to include a part of the first and second adhesive application portions. Thus, an object is to provide electronic equipment that reduces deviation in the relative position between the optical member and the support member generated after the curing of the ultraviolet-curable adhesive.

Abstract: According to one embodiment, an information storage medium includes an organic dye material which records information with a light beam having a wavelength equal to or smaller than 620 nm.

Abstract: According to one embodiment, an information storage medium includes an organic dye material which records information with a light beam having a wavelength equal to or smaller than 620 nm.

Abstract: A light beam emitted from a laser source is divided into a first light beam and a second light beam. An optical divider is further provided to separate a combined light beam of the first and second light beams into a first light bundle near the optical axis and a second light bundle in the edge portion and to diverge the first and second light bundles so that the first and second light bundles are individually detected by plural detectors. The first light beam is signal light focused on an optical information recording medium by an objective lens and reflected off the medium, and the second light beam is reference light not focused on the optical information recording medium. A focus error signal is then detected for the first light bundle for compensating focus error.