Abstract: The optical module includes a housing, a lid that closes an opening of the housing, an optical component arranged inside the housing, and a printed circuit board arranged on a front surface of the lid outside the housing so as to be used as a board on which a control circuit that controls the optical component is mounted. The optical module further includes a side electrode that is provided on a side surface of the housing and configured to be electrically connected to an electrode of the optical component; and a flexible substrate that provides electrical connection between the side electrode and an electrode of the control circuit. The optical module can be miniaturized by integrating the optical component and the control circuit.

Abstract: A resolver includes a resolver rotor fixed to a rotating shaft, and a resolver stator disposed around the resolver rotor. The resolver stator includes an annular stator core having a plurality of salient poles which protrudes radially inward and which is disposed at regular intervals in a circumferential direction. The resolver rotor has an outer peripheral surface defined by an outer radius Rm(?) which is obtained by blending, with respect to a first function Gp(?) where an air gap between the resolver rotor and the salient poles is proportional to a sine wave (sin ?) related to an angle ? of the resolver rotor, a second function Gip(?) where the inverse of the air gap is proportional to the sine wave (sin ?), at a predetermined ratio ?.

Abstract: A sequence of symbols is generated to describe a set of write data, the symbols having a length of nT, where T is a channel clock rate and n is an integer over a predetermined range. Bi-directional write currents are applied to a write pole to record the sequence of symbols to a magnetic storage medium. The write pole has an effective footprint with a downtrack length of mT, where m is an integer. The write currents are switched between a first rail current and a second rail current for alternating symbols, the write currents further transitioning to an intermediate current value for at least one channel clock period for symbols longer than 1T. Write currents are applied to the write pole when recording symbols having a length longer than mT using the effective footprint of the write pole as an interval.

Abstract: An example system may include a first vertical cavity surface emitting laser (VCSEL) that includes a first integrated polarization locking structure to produce a polarized optical data signal. The system may also comprise a second VCSEL that includes a second integrated polarization locking structure, the second integrated polarization locking structure orthogonal to the first integrated polarization locking structure, to produce an orthogonally polarized optical data signal. Lenses may be disposed on the substrate opposite the first VCSEL, to collimate the polarized optical data signal, and opposite the second VCSEL to collimate the orthogonally polarized optical data signal. A polarization division multiplexer may combine the first collimated polarized optical data signal and the second collimated orthogonally polarized optical data signal.

Abstract: A silicon-based photoelectric multiplier comprises a plurality of cells and a number of read-out lines, and at least one of a number read-out pads or a ring-like line, wherein the plurality of cells may be divided into a number of segments, and each one of the read-out lines may be electrically connected with the cells of at least one segment.

Abstract: The magnetic sensor of the invention comprises a base portion, a sensor chip positioned on the base portion, a wiring portion adapted to electrically connect a terminal of the sensor chip to a connecting lead, a resin having a low elastic modulus for coating at least the sensor chip, and a resin having a high elastic modulus for coating at least the low elastic-modulus resin and the wiring portion, wherein the sensor chip includes a magneto-resistive effect device, and the low elastic-modulus resin has an elastic modulus ranging from 10 kPa to 80 MPa while the high elastic-modulus resin has an elastic modulus of 1 GPa or more, and enables the sensor chip to perform well in a good state although having a structure of sealing up the sensor chip with the resin member.

Abstract: Provided is a photo detecting element including a body with an optical sensor and an amplification unit for amplifying a signal output from the optical sensor. The photo detecting element includes a driving voltage port that applies a driving voltage to the amplification unit, a ground port that provides a ground for the amplification unit, and a plurality of output ports interposed between the driving voltage port and the ground port, and outputting a signal received from the amplification unit. The driving voltage port, ground port, and plurality of output ports are disposed on the same one side of the body.

Abstract: Provided is a photo detecting element that has a simplified structure and that is easily manufactured and assembled, and an optical pick-up device including the photo detecting element. The photo detecting element includes an optical sensor, an amplifier for amplifying a signal from the optical sensor, and a non-linear multi-step variable resistor to adjust a gain of the amplifier.

Abstract: An object of the present invention is to achieve both low noise and fast response in an optical signal detecting circuit capable of providing all of three signals—a focus error signal, a tracking error signal, and an RF signal—with only a single detection system. A single current-to-voltage converter converts a current signal obtained by adding currents flowing through two photodiodes, into a voltage signal. Not only currents flowing into the photodiodes, but also currents flowing out from the photodiodes are taken out as the voltage signals. Moreover, by applying two different reference voltages to the current-to-voltage converters, a reverse bias voltage is applied between the terminals of each photodiode.

Abstract: An optical pickup apparatus includes: first and second laser diodes to emit first and second laser beams having first and second wavelengths for reading signals recorded in first and second optical discs, respectively; a first objective lens configured to condense the first laser beam onto the signal recording layer of the first optical disc; a second objective lens arranged, along with the first objective lens, in a radial direction of the first and the second optical discs, the second objective lens configured to condense the second laser beam onto the signal recording layer of the second optical disc; a first optical system configured to guide the first laser beam from the first laser diode to the first objective lens; and a second optical system configured to guide the second laser beam from the second laser diode to the second objective lens independently of the first optical system.

Abstract: In a photo-detector position adjustment/bonding process, it has been necessary for a worker to hold a dangling photo-detector and plate with a tool such as tweezers, and chuck the photo-detector and plate onto an adjustment jig. Because the chucking onto the adjustment jig is performed by a manual operation, productivity is low and it has been difficult to decrease the process standard time (ST). In order to substantially stabilize the standby position of the photo-detector, a pressing force is provided by the reaction force of a flexible substrate in the direction of an optical pickup, and the contacting surfaces of an optical pickup case and the plate are prevented from sliding and displaced from each other.

Abstract: A near-field optical head which can be manufactured using a silicon process and illuminate and detect sufficient light from a very small aperture at all times in a state of stably proximate to a media. The near-field optical head (3000) is structured by a very small aperture (3008) formed at an apex of a taper, a light introducing part (3002) for propagating light in a direction generally parallel with a media, and a light reflection layer (3001) for reflecting the light propagated through the light introducing part (3002) toward the very small aperture (3008). Furthermore, a focusing function is structurally provided for illuminating the light focused on the very small aperture (3008).

Abstract: An optical pickup having a one-plane, two-wavelength diffraction grating and a two-wavelength laser generator is provided in which crosstalk noise caused by leakage of a track error signal into a focus error signal is reduced to improve focus control performance. A main beam and sub-beams generated by the one-plane, two-wavelength diffraction grating and reflected from the surface of an optical disc are incident on corresponding light receiving elements among which the one to receive the main beam and those to receive the sub-beams are relatively shifted in a linear-speed direction of the optical disc. The distance of the shifting is determined based on the characteristic, relative to the relative positions of the light receiving elements, of the leakage of the tracking error signal into the focus error signal detected based on the main beam and sub-beams.

Abstract: High density-information storage is accomplished by the use of novel, near-field optical devices in combination with high-density storage media. The near-field optical devices are configured to focus light to nanoscale spot sizes and may employ negative index of refraction materials for focusing. The high-density storage media may include protein-based storage media, such as photochromic proteins, and high-coercivity magnetic storage media. Light energy provided the optical devices may enable exposed protein molecules to transition between stable molecular states that may be distinguished on the basis of their respective spectral maxima. Light energy provided by the optical device may also be used to heat localized regions of magnetic media to a selected temperature, effecting local changes in coercivity of the magnetic media.

Abstract: An optical pickup apparatus comprising: an objective lens formed so that a first and second laser beams different in wavelength are respectively focused onto signal recording layers of a first and second optical discs; and a photodetector including a square-shaped light-receiving portion for being irradiated with return light, as a spot, of the first or second laser beam respectively reflected from the signal recording layers of the first or second optical discs, to generate a focus error signal, a length of a diagonal line of the light-receiving portion being substantially equal to a longer diameter of an elliptical spot formed in a direction of the diagonal line when the focus error signal is at a maximum level for an optical disc that is either one of the first and second optical discs, to which a laser beam shorter in wavelength out of the first and second laser beams is focused.

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: An astigmatism element converges laser light in first and second directions to generate focal lines. A spectral element makes propagating directions of light fluxes entered into first through fourth areas different from each other to disperse the four light fluxes from each other. The direction along which the first and second areas are aligned is in parallel to a direction of a track image of a recording medium projected onto the spectral element. Each of the first and second areas has a surface area larger than a surface area of each of the third and fourth areas, and a boundary portion between the first and second areas, and the third and fourth areas includes a straight portion extending in a direction perpendicular to the direction of the track image.

Abstract: Two light flux areas are disposed in a direction along which a pair of vertically opposite angles defined by first and second straight lines are aligned, and the other two light flux areas are disposed in a direction along which the other pair of vertically opposite angles are aligned. A spectral element sets propagating directions of divided elements of each of light fluxes obtained by dividing each of the light fluxes by a third straight line intersecting with the first and second straight lines by an angle of 45 degrees, or by a fourth straight line orthogonal to the third straight line to disperse the divided elements on a photodetector. The photodetector is provided with sensors which individually receive the divided elements of the light fluxes.

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

Abstract: Techniques for recording and reading information to/from a recording medium based on positions of a plurality of marks are described herein. Each of the plurality of marks may have the same length. The information may be recorded based on a mark interval between successive marks. Apparatus and a recording medium suitable for use with such techniques are also disclosed.

Abstract: A photoreceiver includes: a first light-receiving section divided into two regions by a border extending in a radial direction, and is disposed in a portion where it can receive a +1st order diffraction ray of the main beam from the polarization hologram, so as to detect a spherical aberration; a second light-receiving section is divided into two regions by a border extending in the radial direction, and is disposed in a portion where it can receive a +1st order diffraction ray of the first sub-beam from the polarization hologram, so as to detect a spherical aberration; and a third light-receiving section is divided into two regions by a border extending in the radial direction, and is disposed in a portion where it can receive a +1st order diffraction ray of the second sub-beam from the polarization hologram, so as to detect a spherical aberration.

Abstract: An optical drive device generates a first push-pull signal and a first sum signal based on a light receiving amount in two light receiving areas of which each width in a signal light tangent direction is smaller than a diameter of a spot of signal light, generates a first normalized push-pull signal by normalizing the first push-pull signal by using the first sum signal, and generates a tracking error signal based on the first normalized push-pull signal.

Abstract: An optical pickup apparatus changes a propagation direction of luminous fluxes, out of a laser light reflected by a disc, in four luminous flux regions set about a laser optical axis so as to mutually disperse these luminous fluxes. A signal light region in which only a signal light is present appears on a detection surface of a photodetector. A plurality of sensors for a signal light are placed at positions irradiated with the signal light within the region. When an arithmetic process is performed on a detection signal outputted from each sensor, a DC component occurring in a tracking error signal is suppressed.

Abstract: To provide an optical head to produce good servo and read signals by reducing the influence of interference by light reflected from a non-read layer of a multilayer optical disc. The head includes: a first optical system for converging light from a light source on a first or second storage layer; a second optical system for receiving and transmitting light reflected from the first layer and stray light reflected from the second layer when the light is converged on the first layer; a photodetector; and a calculator. The photosensitive areas of the photodetector output signals representing intensities of the light incident there through the second system. The reflected and stray light incident on the second system interfere with each other, and the first and second groups of areas are arranged so as to be equally affected by a variation in intensity caused by the interference.

Abstract: A photodetection device is provided with a photoelectric converter portion that converts light to electric current, an electrical current/voltage converter portion, including a feedback circuit that returns at least part of the output to the input side, that converts the electrical current received from the photoelectric converter portion to a voltage corresponding to the resistance value of the feedback circuit and outputs the voltage, where the feedback circuit includes a first MOS transistor that allows the resistance value to be varied in accordance with the gate voltage.

Abstract: The optical pickup device according to the present invention includes: a light source which emits a first light at a first wavelength, a second light at a second wavelength and a third light at a third wavelength; an optical path combining unit which combines vectors of the first, second and third light emitted by the light source, and matches optical axes of the first light and the third light; a light collection unit which condenses the light from the optical path combining unit into the optical information storage medium; a diffraction element which diffracts reflected light from the optical information storage medium; a first photo detector, a second photo detector and a third photo detector which receives the diffracted light from the first diffraction element; and a prevention unit formed between the first diffraction element and the first photo detector, the second photo detector and the third photo detector, and which prevents irradiation of + first-order diffracted light diffracted by the first diffr

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

Abstract: An optical pick-up and a disc apparatus having the same. The inferiority of a tracking signal caused by an adjacent layer during the recording and/or reproducing of an optical disc with multiple recording layers is effectively prevented. The optical pickup includes a light source to emit light with a predetermined wavelength, a light collecting unit to collect the light emitted from the light source to form a light spot on a signal recording layer of an optical disc having a plurality of recording layers, a photodetector to receive the light reflected by the optical disc to detect a signal, and an optical member to change the optical transmission of the light reflected by the optical disc according to an incident angle of the reflected light to decrease an optical transmission of a noise light entering the photodetector.

Abstract: An optical disc apparatus capable of obtaining an effect to reduce the laser noise without shortening the laser diode service life or increasing the power consumption. The optical disc apparatus includes a laser diode for emitting a laser beam, a laser driver for driving the laser diode, a detector for monitoring a first power emitted from the laser diode, a detector for monitoring a second power applied to an optical disc, and an attenuator for attenuating the first power. The light attenuation factor of the attenuator is changed by the ratio between the first power and the second power.

Abstract: An optical pickup includes: a light source that emits a light beam; an object lens that condenses the light beam on a target recording layer of an optical disk; a lens moving unit; a condensing lens; a hologram element that diffracts, in diffracting a reflected light beam and separating it into reflected zeroth-order and first-order light beams, parts of the reflected first-order light beam in a first direction and sets them as first and second beams, diffracts parts of the reflected first-order light beam in a second direction and sets them as third and fourth beams; and a photodetector that receives the first and second beams and the third and fourth beams and generates light reception signals, and receives interlayer stray light of a part of the light beam reflected by the other recording layers other than the target recording layer and generates a stray light reception signal.

Abstract: A method and apparatus for recording/reproducing data is disclosed. The apparatus for recording/reproducing data comprises a diffraction element splitting light diffracted or reflected from a recording medium into a main beam and first and second sub beams, the main beam and the first and second sub beams having no interference from one another; a light-receiving part detecting the main beam and the first and second sub beams; and a controller controlling a position of the diffraction element based on at least one light capacity of the detected beams or the detected position.

Abstract: The optical pickup device according to the present invention includes: a light source which emits light at first, second and third wavelengths; an optical path combining unit which combines vectors of the light at the first, second and third wavelengths which is emitted by the light source, and matches optical axes of the light at the first wavelength and the light at the third wavelength; a light condensing unit which condenses the light from the optical path combining unit onto the optical information storage medium; a diffraction element which diffracts light at the first, second and third wavelength which is reflected from the optical information storage medium, in a first direction and a second direction respectively; a first photo detector which receives light at the first, second and third wavelength that is diffracted in the first direction by the diffraction element; a second photo detector which receives light at the first and third wavelength that is diffracted in the second direction by the diffra

Abstract: An optical disc apparatus includes a laser diode for emitting a laser light, a beam splitter for dividing the laser light into a main beam and sub beam, a main photodetector for detecting the main beam to output a main push-pull signal, a sub photodetector for detecting the sub beam to output a sub push-pull signal, and a subtracter for calculating the main and sub push-pull signals to output a differential push-pull signal, in which an amplification degree of the sub push-pull signal is adjusted so that a DC offset on the differential push-pull signal is adjusted, even in the case where a laser intensity is varied.

Abstract: By increasing the width of a lead terminal 2 connected to a die pad 1 in the vicinity of the die pad 1 and forming a slit 9 and a projecting plate in the lead terminal in the region where resin 5 is formed, it is possible to ensure the holding strength of the lead terminal by the resin 5, as well as ensuring the strength of the lead terminal during the manufacturing process and achieving a reduction in thickness.

Abstract: An optical controller includes a light source for emitting light, an object lens for condensing light emitted from the light source, a light detection unit for receiving light reflected on an optical information recording medium and outputting a signal corresponding to the amount of the light, and a laser control unit for controlling the amount of the light emitted from the light source to the information recording surface on which information is to be recorded or reproduced, based on the recording state of an information recording surface disposed closer to the object lens than an information recording surface on which the information is to be recorded or reproduced.

Abstract: The present invention provides a photodetector capable of generating highly accurate tracking and focusing error signals free of variations in light quantity caused by interference, in an optical pickup with a two-wavelength multilaser. The photodetector comprises first three light receiving areas arranged linearly to receive three light beams respectively resulting from splitting of a light beam emitted from a laser light source of a first wavelength and second three light receiving areas arranged linearly to receive three light beams respectively resulting from splitting of a light beam emitted from a laser light source of a second wavelength longer than the first wavelength. The distance between both-end light receiving areas out of the first three light receiving areas is longer than the distance between both-end light receiving areas out of the second three light receiving areas.

Abstract: In a focus optical system for optical discs or optical disc master exposure apparatuses, a relative positional relation between a cylindrical lens and a 4-division detector in an astigmatic optical system is adjust so that an interference fringe appearing in reflected light derived from an optical disc master is made to be incident on a dead zone of the 4-division detector. Thus, an astigmatic focus servo free from effects of variations in a focus error signal due to the interference fringe is realized. As a result of this, effects of the interference fringe appearing in the reflected light derived from an optical disc or optical disc master can be suppressed.

Abstract: An optical pickup apparatus comprising: a photo detector configured to receive light reflected from a medium; a housing mounted with the photo detector; and a projecting portion projecting from the housing, the projecting portion including a displacement preventer configured to prevent displacement of the photo detector or an adhesive relative to the housing, the displacement preventer including a fixing portion formed to extend along a plurality of directions, the photo detector being provided on the housing by applying the adhesive to the displacement preventer.

Abstract: An information recording/reproducing device irradiates a signal light beam containing arbitrary two-dimensional information and a reference beam emitted from the same light source as the signal light beam to an arbitrary region of a hologram recording medium to record a first hologram. After the first hologram is recorded, the device changes the incident angle of the signal light beam with respect to the hologram recording medium and multiplex-records a second hologram, which is different from the first hologram, in the same region as the region in which the first hologram is recorded by irradiating a signal light beam whose incident angle has been changed and a reference beam substantially the same as the reference beam used when recording the first hologram while the device obtains at least a part of a diffracted beam from the first hologram simultaneously.

Abstract: A two-dimensional demodulation method for reproducing a data page by means of decision feedback Viterbi detection processing from a recording medium on which a data page has been recorded as a set of a plurality of two-dimensional modulation pattern symbols each of which comprises a plurality of pixels, and which have been modulated two-dimensionally, the method comprising: a step of determining a value of pixel deviation in a reproduction image obtained by receiving light from the recording medium on an image sensor; a step of splitting an output signal of the image sensor which indicates the reproduction image of the light received from the recording medium into signal symbol data by division into blocks in accordance with the two-dimensional modulation pattern symbols; and a step of carrying out decision feedback Viterbi detection for each signal symbol data in accordance with the pixel deviation value.

Abstract: A two-dimensional digital data acquisition element includes: a pixel area having a plurality of pixels arranged in a matrix form, each of the pixels having a photoelectric conversion element to convert the reproduced light from the optical information recording medium to an electric signal; selection circuits which select the pixel; a readout circuit which reads out an electric signal of a pixel selected by the selection circuits; and a 1-bit AD converter which converts an output of the readout circuit to 1-bit digital data. A pitch ratio N between a pitch P1 of the unit data areas in the two-dimensional digital image information and a pitch P2 of the pixels in the pixel area defined as N=P1/P2 satisfies a relation A·n2/(An+1)<N<A·n2/(An?1) where A is the number of digital data in one-dimensional direction of one byte of the two-dimensional digital data and n is a natural number of at least 2.

Abstract: An optical disc apparatus comprising: an optical pickup unit having a semiconductor laser that radiates a laser light beam which is to be applied to an optical disc, a photo detector that has a plurality of light-receiving faces, which are disposed adjacent to each other, and each of which is disposed radially at an identical angle from a center of all of the plurality of light-receiving faces, and that, when the plurality of light-receiving faces receive a reflected light beam of the laser light beam applied to the optical disc, outputs photoelectric converted signals, each of which corresponds to a level of the reflected light beam at each of the plurality of light-receiving faces, a plurality of operational amplifiers that respectively output control signals for focus servo or track servo to the optical disc, based on the photoelectric converted signals, and an actuator that executes the focus servo or the track servo, based on the control signals; a driving unit that drives the actuator to execute the foc

Abstract: An operation mode is arranged to be switched between in recording/reproducing and in adjustment. A switching circuit with a hold circuit therefor is on a light receiving element including an optical pickup having a laser light source emitting a laser beam, an objective lens focusing the laser beam onto a recording layer of a disc, and a light receiving element receiving an optical signal modulated. The light receiving element is operable in an adjustment mode for selecting of the signal of an individual light-receiving surface and for outputting the same. The light receiving element is configured so that the address selection signal line in the adjustment mode may be used also as a sensitivity switching signal line. A compact and highly reliable optical pickup with less signal lines can be provided.

Abstract: An apparatus for recording/reproducing holographic data and a method of adjusting a position of a recording layer. While an objective lens focusing first and second lights having different wavelengths on a holographic data storage medium including first and second reflective layers reciprocatingly moves in a direction of an optical axis, a focus movement unit, which moves a focus of the second light in the direction of the optical axis until a time difference between a first detection signal generated when the first light is reflected from the first reflective layer and a second detection signal generated when the second light is reflected from the second reflective layer becomes a value corresponding to a position of a desired recording layer, is controlled to move a focal position of the second light so that the focal position of the second light can be adjusted to the position of a desired recording layer.

Abstract: An optical disk drive system associated with a laser diode is described. The optical disk drive system comprises a current generator for receiving input signals; a current switch coupled to receive timing signals; a current driver coupled to receive output signals from the current switch and the current generator, the current driver further comprising a driver with wave shape control selected from the group consisting of a laser diode read driver and a laser diode write driver, wherein the driver with shape control is operative for transmitting at least one output signal that is a scaled version of at least one of the output signals received from the current generator, wherein the current driver is operative for transmitting at least one output signal driving the laser diode.

Abstract: There are provided a light-receiving element for receiving light reflected from an optical recording medium, an optical head using the element, and an optical recording/reproducing apparatus using the element. In particular, the light-receiving element can be manufactured at low cost and in a simple manner and is configured to receive light from a short-wavelength laser source (having a wavelength of 402 nm to 413 nm). The light-receiving element includes a silicon substrate in which a light-receiving portion is formed; a circuit board for mounting the silicon substrate; at least one or more wires for electrically connecting the silicon substrate and the circuit board; a cover layer for covering the wires; and an exposed portion for exposing the light-receiving portion outside.

Abstract: An optical pickup apparatus aiming at reduction of adverse effect on a tracking control signal and a data signal by preventing the reflected light from the adjacent layers of a multilayer disc changing to a stray light. In this optical pickup apparatus, the reflected light from the optical disc including the stray light from the adjacent layer is once focused with a focusing lens and is then reflected with the reflection plate. A flat attenuation element is provided between the lens and the reflection plate parallel to the optical axis with inclusion of the optical axis under the condition separated from the reflection plate. The reflection plate reflects the reflected light from the relevant layer and the attenuation element shields the reflected light from the adjacent layer. The light returning to the focusing lens includes less influence of the stray light. This light is detected with a detector to become a control signal and a data signal.

Abstract: An optical disc recording apparatus records external data on an optical disc by using a semiconductor laser. The optical disc recording apparatus includes a circuit board. The circuit board is mounted with a power supply source and an MCM (multi chip module). The power supply source outputs at least one power voltage including a first voltage, and the MCM receives the at least one power voltage including the first voltage output from the power supply source. The MCM includes a first circuit and a second circuit. The first circuit includes at least one power supply circuit which generates at least one power voltage including a second voltage. The second circuit receives the at least one power voltage including the second voltage output from the at least one power supply circuit of the first circuit. An optical disc recording method is also described.

Abstract: Even though a laser diode is within the operation guarantee temperature range, the rise time characteristics required to protect and maintain the writing quality right away may not be present at a lower temperature. By sufficiently increasing the rise time, a laser diode control method of the present invention makes it possible to write readily. A laser diode control device includes a temperature sensor for detecting temperature of a laser diode. When a detected temperature by the temperature sensor is equal to or below a predetermined value within the operation guarantee temperature range, a seek motor controls the position of a pickup to move the pickup to a region outside a recording region of a recording medium. In this way, a current exceeding a threshold current value is supplied to the laser diode, and the writing operation starts after the laser diode temperature is increased up to a level where the rise time characteristics required to protect and maintain the writing quality is present.

Abstract: A photodetector integrated circuit (PDIC) capable of being used with at least two different types of optical discs includes a photodetector (PD) array and a switch matrix. The PD array includes a center channel PD and a side channel PD electrically isolated from the center channel PD. The switch matrix, which includes a plurality of inputs and a plurality of outputs, can be selectively configured in a plurality of different switch configurations. The side channel PD includes a plurality of electrically isolated PD sections. Each electrically isolated PD section of the side channel PD is adapted to detect light and provide an electrical output signal, indicative of the light detected by the PD section, to a different one of the inputs of the switch matrix.