Abstract: An optical pickup device includes a semiconductor laser for emitting forward and backward laser light from front and back emergent end faces thereof, focusing device for focusing the forward laser light emergent from the front emergent end face of said semiconductor laser onto an optical recording medium, a light-receiving element for signal reproduction for detecting return light from the optical recording medium, and a light-guiding system for guiding the return light to said light-receiving element for signal reproduction, said optical pickup device being provided with a light source unit having an arrangement in which said semiconductor laser and said light-receiving element for signal reproduction being incorporated in a common package and shielding device, disposed inside said package of said light source unit, for preventing the light emitted from said semiconductor laser from being incident upon said light-receiving element for signal reproduction.

Abstract: An information reproducing apparatus emits an electron beam E from an electron gun 40 to a signal layer 12 of a disk 1, detects a change of the incident intensity of the reflection thereof via a detector 42, and reproduces the information of the disk 1 by a reproducing circuit 5. A recording medium 20 has a conductive layer 22, an insulating layer 23, and island-like fixed electrodes 24 thereon electrically insulated from the periphery with a memory function imparted to the fixed electrodes. For the writing, electrons are injected into the fixed electrodes by the electron gun. For full erasure, a voltage is applied to the conductive layer 22. For the reading, the electrostatic effect of the counter electrodes and the fixed electrodes is utilized. This enables an increase of the volume of information and an enhancement of precision of the reading of the information.

Abstract: An optical head apparatus is provided with a first laser element, a second laser element and a polarized beam splitter. The first laser element emits a laser beam having a first wavelength. The second laser element emits a laser beam having a second wavelength. The second wavelength may be equivalent to the first wavelength, alternatively, it may be different from the first wavelength. The polarized beam splitter enables the laser beams of the first and second laser elements to be simultaneously radiated to the recording layer of an optical disk. When information are recorded in the optical disk, the laser beams of the first and second laser elements are used at the same time. At least one of the laser elements emits a laser beam having such a wavelength as enables the recording layer of the optical disk to absorb the largest possible amount of energy.

Abstract: An optical data storage system, particularly suited for use in the information and entertainment industries. A near-field crystal optical memory (NCOM) system includes an electron trapping media, particularly an &agr;-Al2O3:C crystal or Cu+-doped fused quartz, that is sensitive to light. Information is stored and retrieved using blue and green laser light, respectively. High data density is achieved using a near-field scanning optical microscopy (NSOM) technique, by placing the optical probe in a very close proximity to the crystal surface. The storage system enables ultra-high data densities reaching 2500 Gb/in2.

Abstract: An optical pickup apparatus which supports two wavelengths and is amenable to a reduction in size without employing a combining prism. The optical pickup apparatus employs a semiconductor laser device implemented in the form of a one-chip laser diode having two light sources for emitting a first laser beam and a second laser beam at a wavelength different from that of the first laser beam. A photodetector unit has a first detector section for receiving the first laser beam and a second detector section for receiving the second laser beam, and is set at positions at which the first and second laser beams follow return light paths of different lengths from an optical disc to the first and second detector sections.

Abstract: There is disclosed a substrate unit comprising a light emitting element attachment surface for attaching a light emitting element which emits laser light substantially in parallel to the attachment surface, a light reflecting surface for changing the direction of the light axis of the laser light emitted from the light emitting element by a predetermined angle by reflection, and a light detecting element attachment surface, formed on the same two-dimensional plane as a plane of the light emitting element attachment surface, for attaching a light detecting element which receives light incident from the outside.

Abstract: A small-sized superimposed circuit module has reduced spurious electromagnetic wave emission and small variations in circuit parameters. A resonance circuit portion of an oscillator and a portion of a noise rejection filter are embedded in a multilayer ceramic substrate, and the remaining circuit components are mounted on the surface of the multilayer substrate. The upper surface of the multilayer substrate is covered with a metal case.

Abstract: An optical head includes a (1) light radiating unit in which the relative positions of first and second light sources are set so that a straight line interconnecting a spot position of the laser light illuminated on an optical disc and a spot position of the second laser light similarly illuminated on the optical disc will be 45±15° with respect to a recording track on the optical disc and (2) a light receiving element having plural light receiving sections arranged substantially parallel to a splitting line substantially parallel to the straight line which interconnects the spot position of the laser light illuminated on an optical disc and the spot position of the second laser light similarly illuminated on the optical disc and which is projected on the optical disc.

Abstract: An optical pickup for recording and reproducing information on a plurality of record media respectively, the pickup has

Abstract: The present invention relates to an optical data storage medium and a device and method thereof; and, more particularly, to an optical data storage medium based on semiconductor luminescence, which is capable of limiting searching and recording of optical data to a certain location in three-dimensional, easy multi-stage data searching, controlling of luminescence wavelength, excellent durability of data, requiring relatively low energy compared to a method of damaging silica, one-time-recording and repeated-searching, and to a device and method for searching for and recording optical data based on the photon absorption effect. The method of recording optical data takes a semiconductor-dispersed-thin layer on an optically transparent medium as a recording layer. Data recorded in a certain layer is searched based on the luminescence property of nanometer-sized crystalline semiconductor by using single-photon or two-photon absorption.

Abstract: In accordance with the present invention, a large number of data tracks are recorded on an optical recording media using a vertical cavity surface emitting laser (VCSEL) array. By selecting the number of laser array elements to exceed the number of recorded tracks, an increase in the recording density is possible by modulating the width, as well as length, of each recorded mark.

Abstract: An optical head apparatus is provided with a first laser element, a second laser element and a polarized beam splitter. The first laser element emits a laser beam having a first wavelength. The second laser element emits a laser beam having a second wavelength. The second wavelength may be equivalent to the first wavelength, alternatively, it may be different from the first wavelength. The polarized beam splitter enables the laser beams of the first and second laser elements to be simultaneously radiated to the recording layer of an optical disk. When information are recorded in the optical disk, the laser beams of the first and second laser elements are used at the same time. At least one of the laser elements emits a laser beam having such a wavelength as enables the recording layer of the optical disk to absorb the largest possible amount of energy.

Abstract: A method of initializing a phase-change optical information recording medium is provided, using an optical system incorporating a semiconductor laser device. The laser device is characterized by a specified spatial power distribution. In a spatial distribution of the laser power focused on the recording medium, in the direction perpendicular to guide tracks the laser device preferably has less average smaller in both end regions of the spatial distribution, which have each 10% of the width at half maximum of the distribution, than the average in the center region of the full width at half maximum of the distribution.

Abstract: An optical pickup device includes a semiconductor laser for emitting forward and backward laser light from front and back emergent end faces thereof, focusing device for focusing the forward laser light emergent from the front emergent end face of said semiconductor laser onto an optical recording medium, a light-receiving element for signal reproduction for detecting return light from the optical recording medium, and a light-guiding system for guiding the return light to said light-receiving element for signal reproduction, said optical pickup device being provided with a light source unit having an arrangement in which said semiconductor laser and said light-receiving element for signal reproduction being incorporated in a common package and shielding device, disposed inside said package of said light source unit, for preventing the light emitted from said semiconductor laser from being incident upon said light-receiving element for signal reproduction.

Abstract: An optical pick-up apparatus for recording and reproducing information from recording media using a first, second, and third light source to emit light beams having various wavelengths corresponding to a first, second and third recording media, respectively. A dichroic beam splitter has a first, second, and third input surface for receiving the light beams emitted from the first, second and third light sources, respectively, and an output surface through which the light beams received through the input surfaces is transmitted toward the first, second, and third recording media. A converging device converges the light beams transmitted through the output surface of the dichroic beam splitter toward the first, second, and third recording media, and a photodetector receives light beams reflected from the first, second, and third recording media that has been transmitted through the dichroic beam splitter.

Abstract: Methods of writing information to an optical memory device. The methods comprise the step of writing a mark to the active material of the optical memory device by irradiating the material with an applied energy source. In one embodiment, the applied energy source provides a plurality of energy pulses. In another embodiment, energy in excess of that required to form a mark is released and dissipated in a manner that minimizes mark enlargement, spurious mark formation, recrystallization and back crystallization. The methods are effective to provide better cooling characteristics through enhancement of the capacitive cooling contribution.

Abstract: The invention pertains to a control circuit (4) for a radiation source (2). The circuit comprises means (43) for generating an error signal (Perr) which is indicative for a difference between a measured average value of the output power of the radiation source (2) and a desired average value (Pset) of the output power of the radiation source. The circuit further comprises combining means (44, 45, 46) for generating a control signal (Sout) for the radiation source (2) in response to said error signal (Perr) and to an information signal (Sin) for modulating the radiation source. The combining means comprise first means (44) for modifying the information signal by a multiplicative factor &ggr; which is dependent on the error signal, and second means (45, 46) for modifying the information signal by an additive factor &sgr; which is dependent on the error signal.

Abstract: The present invention has for its object to provide a compact and simplified optical pickup device which secures sufficient quantity of converged light required for recording and reproducing onto/from respective optical disks, can obtain required imaging magnification of respective optical systems, and does not generate performance degradation at lens shift, when recording or reproduction is performed onto/from optical disks with different base material thickness by plural optical systems of a single optical pickup device.

Abstract: A device suitable for manufacturing an optical registration carrier, such as a master plate, which device comprises a support for said optical registration carrier, at least a first and a second light source, wherein the wavelengths of the light from said first and said second light source are different from each other, as well as an objective disposed between said light sources and said support, which is movable with respect to said light sources. A correction lens is disposed between the first light source and the objective, which correction lens can be moved jointly with the objective. The focal points of the two light sources at least substantially coincide with various movements of the objective and the correction lens with respect to the light source.

Abstract: An object of the present invention is to stably manufacture a semiconductor laser element having a plurality of wavelengths without split of a wafer in a wafering step while preventing a tracking error due to the returning light of three beams in one semiconductor laser. The present invention provides a semiconductor laser element, which comprises a plurality of emitting regions formed on one substrate, each region having different wavelength, wherein at least one side portion of at least one emitting region is opposed to a part of the substrate.

Abstract: An optical pickup apparatus has a simplified configuration for using a plurality of laser beams at different wavelength to reduce the size, and a laser diode chip for use therewith. An irradiation light path for leading a laser beam emitted from a light emitter to a recording medium is provided with an optical axis correcting element for passing a first laser beam and for diffracting a second laser beam having a wavelength different from that of the first laser beam to generate diffracted light which has the optical axis substantially matching the optical axis of the first laser beam. The optical axis correcting element is arranged at a position at which the center of a light intensity distribution of the first laser beam incident thereto matches the center of a light intensity distribution of the second laser beam incident thereto.

Abstract: A transmission diffraction grating body including a base material being substantially transparent with respect to wavelength &lgr;1 and having a refractive index n0; another base material being substantially transparent with respect to wavelength &lgr;1 and having a refractive index n1, which is formed on the base material having a refractive index n0; and a relief diffraction grating formed on the base material having a refractive index n1; wherein the refractive indexes n1 and n0 satisfy the relationship: n1>n0. Thus, the base material having a refractive index n1 can be formed of a high refractive index material, and when the depth of grating of the diffraction grating is set so that the diffraction grating diffracts the light with wavelength &lgr;1 and does not diffract the light with wavelength &lgr;2, the depth of grating of the diffraction grating can be made to be shallow, thus preventing the loss of the amount of the light with wavelength &lgr;1.

Abstract: An optical pickup unit includes first and second light sources of first and second wavelengths, respectively, a dichroic element, a phase plate, and an objective lens. One of the first and second light sources is selected so that information recording or reproduction is performed by converging a light beam emitted from the selected one of the first and second light sources on an optical recording medium via the dichroic element, the phase plate, and the objective lens.

Abstract: An optical pickup apparatus is characterized in that the optical pickup apparatus comprises a light emission part 60 for emitting first and second laser beams having different wavelengths from each other, a grating 62 for generating a pair of sub-beams from the laser beam emitted from the light emission part, and a hologram 63 for generating plus and minus high-order beams from the laser beam reflected by a recording medium to guide the high-order beams to a light receiving part, and the light receiving part comprises a pair of three-division light receiving elements for receiving the plus and minus high-order beam generated from the first or second laser beam reflected by the recording medium, respectively, to generate a focus error signal by a beam size method and two pairs of sub-beam light receiving elements provided by one pair with respect to each of a pair of the three-division light receiving elements, the two pairs of sub-beam light receiving elements for receiving the high-order beams generated from

Abstract: According to the present invention, a semiconductor laser drive device is provided with a high-frequency superimposing circuit to superimpose a high-frequency current on a laser diode and a superimposed frequency changing circuit to change the superimposed frequency and the amplitude of high-frequency current responsive to an operation mode of an optical disk device, wherein the respective superimposed frequency and the amplitude between at least a first output power and a second output power from the semiconductor laser are changed in response to the operation mode of the optical disk device. This not only enables the high-frequency superimposition of a plurality of frequencies and the mode optimization but also facilitates the reduction of laser noises.

Abstract: An optical device having an irradiated portion formed of an optical recording medium in which a pit is formed on a reflection surface, a semiconductor unit in which a semiconductor laser, a semiconductor structure and a photo-detection element are formed on the same semiconductor substrate, and a converging device for converging a light emitted from the semiconductor laser and irradiating the same of the irradiated portion and further converging a returned light reflected from the irradiated portion. The semiconductor structure is formed near the confocal of the converging device and includes at least three reflection surfaces. The photo-detection element includes a first detection element for receiving a returned light reflected on the second reflection surface and a second detection element for receiving the returned light reflected on the third reflection surface.

Abstract: A light source device for an optical head apparatus comprises at least one laser diode chip and a semiconductor substrate integral with the laser chip. The light source device is formed in a recess of the semiconductor substrate for aligning the laser diode chip on a surface of the semiconductor substrate by a semiconductor processing technique. The recess comprises a first side surface for defining a laser beam emitted from the laser diode chip in an optical axial direction and a second side surface for defining a direction perpendicular to the optical axial direction.

Abstract: Disclosed are an apparatus for initializing an optical recording medium to be initialized with stability and ease without employing any focus servo means, and a phase-changing optical recording medium initialized by the initializing apparatus to have a recording layer in a uniform crystalline state over an entire area of the medium which takes part in recording and reproduction of an information signal. In the apparatus for initializing a phase-changing optical recording medium, a laser beam emitted from a laser beam source is irradiated to a recording layer, in an amorphous state, formed in an optical recording medium to be initialized, which is a pre-stage member of the phase-changing optical recording medium, for changing the recording layer into a crystalline state. The laser beam source, e.g.

Abstract: An optical head includes a light radiating unit in which the relative positions of first and second light sources is set so that a straight line interconnecting a spot position of the laser light illuminated on an optical disc and a spot position of the second laser light similarly illuminated on the optical disc will be substantially perpendicular to a recording track on the optical disc, and a light receiving element having plural light receiving portions which are obtained on splitting by a splitting line substantially parallel to the straight line interconnecting the spot position of the laser light illuminated on an optical disc and the spot position of the second laser light similarly illuminated on the optical disc and which is projected on the optical disc.

Abstract: A method and apparatus for recording and reproducing data on and from an optical disk. The recording/reproducing apparatus records the data on an optical disk exhibiting a difference in an optical absorption rate between wavelengths using a light beam having a wavelength of a first standard. The data recorded on the optical disk is reproduced using a light beam having a wavelength of a second standard.

Abstract: An optical pickup device with the capability to read data from and write data to different kinds of optical discs in different formats and a composite optical device used in the optical pickup device. An optical pickup device is made by combining two laser couplers LC1 and LC2 that are designed for optimum read/write specifications for optical discs which are different in format from each other. In one embodiment, two laser couplers LC1 and LC2 are incorporated on a common photodiode IC to form a single laser coupler, and the laser coupler is used in an optical pickup device.

Abstract: In a method, a light emitting portion of a light spot forming device is formed. The light emitting portion has a minute opening, and a light collecting portion for collecting the light coming from a light source for light spot formation to the minute opening. A light emitting portion base film and a resist film are successively formed on the light collecting portion. A light intercepting mask and a light amount detecting device are arranged. The position of the light intercepting mask is adjusted such that the light from the light source is collected by the light collecting portion onto the base film, and is received by the light amount detecting device, and the amount of light detected by the device takes on the maximum value. The resist film is exposed with the light from a light source for exposure through the through-hole in the mask to form a through-hole for etching.

Abstract: Laser light emitted from the wavelength-locked GaN semiconductor laser is collimated through a collimation lens, led through a polarization beam splitter and a ¼ wavelength plate, and converged by a focus lens so as to be radiated on pits formed in an optical disk medium. The signal light from the optical disk medium is collimated by the focus lens, and has its polarization direction turned by the ¼ wavelength plate by 90° relative to its polarization direction before being returned from the optical disk medium. As a result, the signal light is reflected from the polarization beam splitter so as to be converged on the optical detector by the focus lens.

Abstract: A data recording/reproducing apparatus wherein various data to be used for maintenance are measured, and parameters required for analysis of the maintenance data are prerecorded to realize prediction of the service life of a semiconductor laser and detection of occurrence of any trouble that may be derived therefrom. In this apparatus where data are recorded in and/or reproduced from a recording medium, the internal state of the apparatus is measured, then any abnormal state in the apparatus is detected on the basis of abnormal state decision data, and the detected state is transmitted to an external information processor. The apparatus comprises a means for measuring first data relative to the apparatus; a first memory means for storing second data to make a decision as to an abnormal state of the measured first data; a means for generating third data relative to maintenance of the apparatus on the basis of the first and second data; and an output means for delivering the third data as an output.

Abstract: The invention provides a pickup head used in an optical data storage system. The pickup head contains a diffractive optical element (DOE) stack on a semiconductor substrate. The DOE stack includes multiple diffractive lenses for providing several diffractive surfaces and a middle layer serving as a beamsplitter and servo-generating element for a light reflected from an optical storage medium. The middle layer is sandwiched by the diffractive lenses that are located on both outer parts of the DOE stack. The semiconductor substrate includes at least a laser source and several photodetectors. The middle layer serving its function preferably includes a polarization-selective DOE and a quarter-wave retarder oriented to rotate a polarization state of the laser source, so that only the light reflected from the optical storage medium is diffracted by the polarization-selective DOE.

Abstract: The present invention provides for a optical head device having a beam-guiding optical device to bring beams of different wavelengths which are emitted by separate light sources together onto the same optical axis or to guide the beams onto a common photo receiving device. The beam-guiding optical device includes an incident plane and an exit plane and the incident plane and the exit plane are back to back. One of the incident plane and the exit plane has a stair-like surface wherein a step height between neighboring treads in the stair-like surface is set to cause a phase difference of n wavelength to one of the beams passing through the neighboring treads and n is equal to 1, 2, 3 . . . .

Abstract: An optical pickup of an optical disk drive. The optical pickup includes a laser beam source for generating a laser beam; a pickup base having an objective lens for projecting the laser beam generated from the laser beam source to an information recording surface of an optical disk; a variation adjusting plate which is movably disposed on the pickup base to be moved in vertical and lateral directions, and has a rotational hole formed at a central portion thereof; and a rotation adjusting plate including a rotational section having a predetermined curvature which is inserted into the rotational hole of the variation adjusting plate, and with a laser beam source fixed therein, the rotation adjusting plate being rotated with respect to the variation adjusting plate. An optical system including a collimating lens and a reflective mirror is fixed to the pickup base.

Abstract: The multi-channel optical head for recording and reading optical storage data has a write laser array for generating a plurality of write beams and a read laser array for generating a plurality of read beams. The write beams and the read beams share a common optical path with a first broadband non-polarizing beam splitter which directs the beams towards the optical recording medium or to a power detector and with a second broadband non-polarizing beam splitter which directs the write beams and the read beams to the optical recording medium and which directs the read beams, after retroreflection and information modulation from the optical recording medium, to be split by a beam splitter and focused onto a detector to provide focusing information and another detector which detects its intensity to read data and provides tracking information.

Abstract: There is provided a near-field optical memory head for recording and/or reproducing information on a recording medium by utilizing near-field light which is a near-field optical memory head having a compact constitution and is suitable for mass production and array formation. According to the near-field optical memory head 11, in a planar substrate formed by penetrating at least one hole in a shape of an inverted pyramid such that a top portion thereof constitutes a very small aperture 4, a near-field light forming system for forming near-field light at a recording medium 1 and a near-field light detecting system for guiding propagating light 10 provided by interactively operating the formed near-field light with the very small aperture 4 to a light detecting element are integrated.

Abstract: A two-color hologram recording/reproducing apparatus is capable of directing interferable signal light and reference light into a hologram recording medium to record an information signal carried by the signal light. The hologram recording medium is sensitive to a first light at a first wavelength in an ultraviolet or short-wavelength visible light band to develop light induced absorption. The apparatus includes a light source for irradiating the hologram recording medium with the first light, a laser light source for irradiating the hologram recording medium with signal light and reference light at a second wavelength longer than the first wavelength after the first light is irradiated, and a gate light source for directing gate light at a third wavelength into the hologram recording medium.

Abstract: The multi-channel optical head for recording and reading optical storage data has a write laser array for generating a plurality of write beams and a read laser array for generating a plurality of read beams. The write beams and the read beams share a common optical path with a first broadband non-polarizing beam splitter which directs the beams towards the optical recording medium or to a power detector and with a second broadband non-polarizing beam splitter which directs the write beams and the read beams to the optical recording medium and which directs the read beams, after retroreflection and information modulation from the optical recording medium, to be split by a beam splitter and focused onto a detector to provide focusing information and another detector which detects its intensity to read data and provides tracking information.

Abstract: An optical pick-up device includes a light emitting unit for directing a laser beam onto a storage medium; a reflecting member that reflects the laser beam emitted from the light emitting unit in a direction substantially perpendicular to a storage surface of the storage medium; and a focusing member that focuses the laser beam reflected from the reflecting member onto the storage surface of the storage medium, the light emitting unit being mounted at an angle such that an axis of the laser beam directed onto the reflecting member from the light emitting unit and an axis of the laser beam reflected onto the storage medium form an angle of less than 90 degrees, a position from which the laser beam is emitted from the light emitting unit being provided in a direction closer to the storage surface of the storage medium from a center of the light emitting unit.

Abstract: An optical pickup of this invention includes a first laser beam source having a wave length of 780 nm and a second laser beam source having a second wave length of 650 nm wherein the first laser beam source and the second laser beam source are disposed in the vicinity of each other, emission lights from the first laser beam source and the second laser beam source are emitted along substantially the same optical axis and a reflected light from the information recording medium is returned along the optical axis; the first diffraction grating, the second diffraction grating and the light receiving device substrate are disposed in order, the first diffraction grating is substantially transparent for a wave length of 780 nm and diffracts a wave length of 650 nm, and the second diffraction grating is substantially transparent for a wave length of 650 nm while it diffracts a wave length of 780 nm.

Abstract: In an optical pickup apparatus for reproducing information from one of different kinds of optical information recording medium, provided with a first light source; a second light source; and an objective lens having a first aspherical surface and a second surface, the first aspherical surface has a first divisional surface, wherein a distance on the optical axis between the second surface and a crossing point at which a line extended in accordance with a formula of an aspheric surface from the second divisional surface intersects with the optical axis is determined in such a manner that a peak strength ratio of converged first light flux on the first information recording plane of the first optical information recording medium is not less than 0.9 and a peak strength ratio of converged second light flux on the second information recording plane of the second optical information recording medium is not less than 0.8.

Abstract: Electrodes carrying FAD-dependent enzymes on their surface are enclosed. The FAD is modified to include a functional group or moiety which affects the properties of the enzyme. The functional group or moiety can be a binding moiety through which the FAD-enzyme complex is immobilized onto the electrode; it can be an electron mediator group for transferring electrons between the electrode and the FAD; or it can be a photoisomerizable group which can undergo photoisomerization which yields a change in the rate of the electrically induced catalytic activity of the enzyme. The electrodes can be used in electrochemical systems for deforming analytes in liquid medium or for recordal of optical signals.

Abstract: In an optical pickup apparatus of the present invention, either a first laser diode emits a laser beam having a first wavelength or a second laser diode emits a laser beam having a second wavelength. An optical system focuses one of the two laser beams onto a recording surface of an optical recording medium. A photodetector unit receives reflection beams, which are reflected from the recording medium, to generate detection signals from the received reflection beams. A holographic unit has a first hologram suited to the first laser diode and a second hologram suited to the second laser diode, the first hologram provided to diffract a reflection beam of the laser beam of the first laser diode to the photodetector unit, and the second hologram provided to diffract a reflection beam of the laser beam of the second laser diode to the photodetector unit.

Abstract: A multiple channel scanning device has a scanning head with multiple columns of apertures that emit light which is projected to a small spot on the surface of a recorded medium. Light returned from the medium reenters the apertures and is conducted to detectors. In a preferred embodiment, the scanning head is rapidly oscillated (may be on the order of 100 kHz rate), in a direction parallel to the columns. The medium is moved in a direction perpendicular to the columns so that the same recorded regions pass beneath successive columns of apertures. The data from the detectors is image-processed to improve the quality of data reading using the successive readings of the same data regions. This allows errors to be corrected and throughput to be improved.

Abstract: In an optical disc apparatus, a semiconductor SLD driving device is mounted on an optical pickup in order to realize a high speed switching of drive current for a semiconductor laser diode (SLD), necessary for recording data. The SLD is placed. within 5 cm from the SLD driving device. The driving device becomes a heat source due to driving current of the SLD, and increases a temperature of the optical pickup. Since the temperature rises proportionally to power consumption, power saving is required. A voltage supplied to the driving device is controlled to be a minimum level necessary for keeping the driving device still working on basic functions. The SLD driving device is mounted to the optical pickup, and this driving device handles N pieces of input signals for setting semiconductor laser power and N pieces of switch-timing-input-signals for selecting respective input signals.

Abstract: An optical head including a distributed feedback laser having first and second cladding layers, an active layer sandwiched between said first and second cladding layers, a first reflecting member having a periodic wave-shaped structure formed within said first cladding layer at an interface between said active layer and said first cladding layer or in close proximity to said active layer, a second reflecting member provided on a first end surface of an assembly of said first and second cladding layer and active layer and having an exit window formed by a fine aperture, a third reflecting member provided on a second end surface of said assembly, and first and second current injection electrodes electrically connected to said first and second cladding layers, respectively as well as to an injection current source for injecting a current modulated in accordance with information to be recorded on the optical record medium into the laser.

Abstract: A reflectance increasing type optical information recording medium in which the crosstalk is inhibited in the land and groove recording. This optical information recording medium comprises a substrate having a groove and a land provided between adjacent grooves and a recording layer that is provided on the substrate and that changes the reflectance by irradiation with light beams. In this recording medium, the reflectance after recording is greater than the reflectance before recording. Moreover, the depth D of the groove is set to be in the range of &lgr;/8n to 3&lgr;/8n, where the wavelength of the light beam is &lgr; and the refractive index of the substrate is n. And the difference, &Dgr;&phgr;=&phgr;1−&phgr;0, between the phase &phgr;1 of the reflected light after recording and the phase &phgr;0 of the reflected light before recording is in the range of (−0.1+2 m) &pgr; to (0.1+2 m) &pgr;, where m is an integer.