Abstract: A unit according to the present invention includes a substrate and an IC chip used for driving a light-emitting device. A relay terminal is provided at a region spaced from peripheral areas of the substrate so as to connect the light-emitting device with the IC chip. The relay terminal is connected with a corresponding terminal of the IC chip via a connecting channel such as wire-bonding. The light-emitting device is supported by the substrate such that a terminal of the light-emitting device is electrically connected with the relay terminal. A length of a wiring line between the light-emitting device for an optical pick-up and the unit used for driving the light-emitting device is decreased.

Abstract: An information recording reproduction apparatus includes a laser light source, a laser driving unit which supplies a laser driving signal to the laser light source to make it emit a laser light for recording and reproduction, a high frequency superimposing unit which superimposes a high frequency signal to a laser driving signal and a duty controlling unit which controls a duty ratio of the high frequency signal. The high frequency superimposing unit superimposes the high frequency signal on the laser driving signal driving the laser light source in order to prevent an effect due to a return light from an optical disc. The duty controlling unit controls the duty ratio of the high frequency signal so that generation of a higher harmonic component in the high frequency signal is decreased or so that the duty ratio becomes approximately 50%, for example.

Abstract: A hologram reproduction apparatus includes a light-receiving unit such as a two-dimensional sensor which obtains two-dimensionally modulated image data, and an A/D converter which A/D-converts analog data obtained by the light-receiving unit into digital data. In addition, the hologram reproduction apparatus detects a number of pixels having a digital value larger than a first defined value in the A/D-converted image data for one page, by a first pixel number detecting unit. The hologram reproduction apparatus controls a magnitude value of the image data at the time of the A/D conversion by the first control unit so that the number of detected pixels is within a predetermined range. Thereby, a dynamic range of the A/D conversion to the two-dimensional modulated image data can effectively be used. Therefore, a quantization noise due to the A/D conversion can be reduced, and also a reproduction S/N can be improved.

Abstract: A recording/reproducing apparatus includes an optical pickup having an objective lens, an actuator for operating the lens, an aberration correction element, and a detector for generating a reading signal; a servo control section; a driver for operating the aberration correction element; a generator for generating a focus disturbance signal and an aberration correction disturbance signal having a period different from that of the focus disturbance signal; and a controller for adjusting the focusing position and the aberration correction amount on the basis of a change in a predetermined characteristic value of the reading signal when the disturbance signals are simultaneously applied.

Abstract: An optical disc player having an optical pickup records and retrieves information on an optical disc while the optical disc is rotating. A rotation pulse is generated each time the optical disc rotates through a prescribed angle. A rotation frequency data representing a frequency of the rotation pulse is also generated. A servo processor performs servo processing for rotation control on the optical disc in accordance with the rotation frequency data. A sampling pulse generator performs computational processing on an input data signal to generate a sampling pulse. The sampling pulse generator also corrects the rotation frequency data based on a phase error between the sampling pulse and the rotation pulse to use a corrected rotation frequency data as the input data signal. Another servo processor performs servo processing for repetitive control on the optical pickup using the sampling pulse.

Abstract: A drive apparatus including: a superposition device which superposes a superposition signal on a drive signal for driving a light beam emission device that emits a light beam and which outputs the drive signal on which the superposition signal is superposed to the light beam emission device, a reference clock signal generation device which generates a reference clock signal, a frequency change device which changes a frequency of the superposition signal based on a quality index for indicating a quality of a reproduction signal that is obtained from a reflection light that is the light beam reflected on a record medium, a phase locked loop device which controls the changed frequency so as to be constant by a feedback method in use of the generated reference clock signal.

Abstract: An rotation speed controlling apparatus of an optical recording medium having a wobbled track includes an optical pickup for irradiating a light beam to generate a reading signal according to a wobbling shape of the track; a filter having a predetermined frequency band to pass a wobble reference frequency therethrough for extracting a wobble signal from the reading signal; a generator for generating a wobble reference signal; a detector for detecting the difference between the wobble signal frequency and the wobble reference frequency; a controller for controlling the rotation speed on the basis of the difference between the frequency of the extracted wobble signal and the wobble reference frequency; and a discriminator for discriminating that the wobble signal frequency lies outside the frequency band of the filter; wherein the controller controls the rotation speed in accordance with the detected frequency difference when the wobble signal frequency lies outside the frequency band of the filter.

Abstract: A marker for position detection is included in a spatially-modulated pattern of recording information, and an object light is generated and the recording information is recorded on a recording medium. From a detected light from the recording medium, information data corresponding to the recording information and marker data are detected by a two-dimensional sensor. By making unit light-receiving element sizes of marker detecting area and data detecting area of the two-dimensional sensor different, detection accuracy of the marker position can be improved. In addition, by making a bit length of the detected marker data longer than a bit length of the information data, the detection accuracy of the marker position can also be improved. Further, by outputting the detected marker data prior to the information data, a process such as a marker position detection and a geometrical correction can be started in an early stage, and reproduction of the recording information can rapidly be performed.

Abstract: The hologram recording and reproducing apparatus includes a recording unit which records information on a holographic recording medium by recording interference fringes formed by irradiation of a reference light and an object light corresponding to recording information, a reproducing unit which generates detected information data and a focus error signal on the basis of detected light from the holographic recording medium, and a focus servo unit that carries out focus servo on the basis of the focus error signal. The focus servo unit has a servo target value setting unit which sets a target value for focus servo on the basis of the detected information data. The detected information data also includes information indicative of the position relationship between the recording medium and the reference light or the like.

Abstract: A servo control apparatus of an optical pickup includes an extractor for extracting an error signal from a read signal; an equalizer including a phase compensator for equalizing the error signal to generate a drive signal; a driver for changing the servo position of the optical pickup in response to the drive signal; a dropout detector for extracting an envelope signal from the read signal to detect a dropout of the read signal; and a controller. The controller changes an equalization characteristics of the equalizer in accordance with an amplitude of the envelope signal during the period of time when the dropout occurs or in response to an occurrence of the dropout.

Abstract: A driving device includes a superimposing unit, a reference clock signal generating unit and a control unit. The superimposing unit superimposes a superimposed signal on a driving signal that drives an optical beam radiating unit for radiating an optical beam, and outputs the driving signal, on which the superimposed signal is imposed, to the optical beam radiating unit. The reference clock signal generating unit generates a reference clock signal. The control unit keeps a frequency of the superimposed signal constant on a basis of a feedback system utilizing the reference clock signal thus generated.

Abstract: An optical pickup is provided for preventing an objective lens from colliding with an optical recording medium at the stage of initial adjustments. The optical pickup device comprises a servo circuit, and a lens driver for driving an objective lens. In the servo circuit, a drive signal generator supplies the lens driver with one of a first focus drive signal for moving the objective lens in a direction closer to an information recording layer, and a second focus drive signal for moving the objective lens in a direction away from the information recording layer. A controller in a timing generator switches a signal supplied to the lens driver from the first focus drive signal to the second focus drive signal when the level changes by a predetermined range or more in a servo signal which is generated during a period in which the first focus drive signal is being supplied to the lens driver.

Abstract: In a tracking controller for an optical pickup, a photodetector having four light reception parts receives return light from an optical disc and outputs light detection electric signals. Predetermined addition and subtraction operations are performed on the light detection electric signals from the light reception parts. A phase comparator compares phases and outputs a pseudo radial contrast signal. Bringing into tracking servo control is performed based on the pseudo radial contrast signal.

Abstract: A control device includes an a focus controller for performing a focus servo control and a focus jump control; an aberration corrector; a command generator for commanding the change of a recording/reading layer from one recording layer to the other layer; a portion for changing an aberration correction value to a value suited for the other recording layer; and a timing adjuster for adjusting an execution timing of the focus jump and a rate of change in the gain of the amplifier in such a manner that a timing when the gain of the amplifier reaches the predetermined gain is within the execution time period of the focus jump.

Abstract: A controller includes a servo-controller for performing nonlinear and linear control of the read/write position according to an error signal to drive an actuator for driving the pickup; a switch for switching the servo-controller from open-mode to closed-mode according to the error signal; and an adjuster for adjusting the gains of the nonlinear and linear control so that the nonlinear control component is larger than the linear control component at the time of switching and the linear control component is larger than the nonlinear control component after the elapse of a predetermined time from the time of switching.

Abstract: A servo control apparatus is provided to a stable servo control even when delays occur in detecting defects. Based on reflected light of an optical beam from an optical disc, a defect resulting from dark spots, damages, or others on the optical disc is detected. Immediately before the detection, sample data of a control signal are memorized. The sample data are obtained during a predetermined interval of time that corresponds to a detection delay for the defects, which is dependent on a defect detecting device. Using the memorized sample data, a cancel signal is produced for canceling the influence of the control signal, which is owing to a pseudo error signal obtained during the predetermined interval of time. The cancel signal is outputted as the control signal immediately after the detection of the defect.

Abstract: In a tracking controller for an optical pickup, a photodetector having four light reception parts receives return light from an optical disc and outputs light detection electric signals. Predetermined addition and subtraction operations are performed on the light detection electric signals from the light reception parts. A phase comparator compares phases and outputs a pseudo radial contrast signal. Bringing into tracking servo control is performed based on the pseudo radial contrast signal.

Abstract: An optical pickup apparatus comprises a semiconductor laser output controller for emitting laser beam, a photodetector for detecting the emitted laser beam, a sampling processor for performing a sampling process, an averaging processor for performing an averaging process, a pulse current generator for generating erase current pulses, write current pulses, and read current pulses, and a controller 200 for controlling the above components. The apparatus adds averaged values and sampled values and controls the semiconductor laser output controller based on the result of the addition and on the current pulses.

Abstract: An optical pickup apparatus comprises a semiconductor laser output controller for emitting laser beam, a photodetector for detecting the emitted laser beam, a sampling processor for performing a sampling process, a pulse current generator for generating erase current pulses, write current pulses, and read current pulses, and a controller for controlling the above components. The apparatus performs the sampling process and generates the current pulses according to a predetermined APC timing and controls the semiconductor laser output controller based on the sampling process and current pulses.

Abstract: A power controller is provided which can control the emission power from a light source to follow an appropriate response property based on a target value. The power controller includes feedforward systems for allowing currents corresponding to target values set at target value setting units to be switched at a switching device and supplied as a power setting current to an adder. Also included are feedback systems for detecting the power of the laser beam emitted by a semiconductor laser serving as the light source and adjusting a feedback current to stabilize the deviation from the target values at a predetermined value. Further included are a switching device for allowing the target values to be switched and supplied to the aforementioned feedback systems, and the adder for adding a feedback current and the power setting current to thereby generate a drive current for driving the semiconductor laser.