Abstract: An optical disk recording and reproducing apparatus operates in a read mode for controlling a laser driver to maintain a laser power at a target read level so as to read a signal from an optical disk, and operates in a write mode for controlling the laser driver to alternate the laser power between a target write level and a target bottom level comparative with the target read level so as to write a signal into the optical disk. In the write mode, a value obtained by sampling and holding the bottom level is set as the target value of a bottom level, and a bottom level control signal is outputted according to a difference between this target value and the detected value of the bottom level. Thus, the laser power control can be performed without any errors being generated even if an offset has occurred in the detected bottom power. Thus, the bottom laser power can be maintained constant.

Abstract: In recording on an optical disk of the write-once variety, the light beam is switched to write intensity during the durations of write pulses and to read intensity during their spacings. The read intensity beam reads the wobbling pregroove in the disk for tracking control, disk speed control, track address detection, and so forth. A beam Intensity control system is provided for constantly holding the read intensity, as well as write intensity, of the laser beam at a target value. Included are a read intensity target generator for generating a read intensity target signal, and a read intensity control circuit for supplying to a laser driver circuit a read intensity control signal indicative of the difference between the read intensity target signal and an actual read intensity signal.

Abstract: A laser power controller detects the temperature and current setting used for the recording power during initial learning or the previous recording operation. When a new recording operation starts, the controller detects the temperature again and compared the detected temperature with the temperature at initial learning or the previous recording to adjust the current setting used for the previous recording power setting and set the initial recording power current of the new recording operation.

Abstract: In an optical recording/reproducing apparatus of the present invention, a semiconductor laser driver supplies a selected one of a plurality of drive currents, including at least a first-level drive current and a second-level drive current, to a semiconductor laser to control the emission of a laser beam by the laser. A current driver selectively outputs one of a plurality of increment currents to the laser driver in response to control signals, the plurality of increment currents including a first increment current supplied to the laser driver during an automatic power control process and a second increment current supplied to the laser driver during a special power setting process.

Abstract: An apparatus for recording and/or reproducing information on and/or from a magneto-optical disk including an optical head for projecting a laser beam onto a magneto-optical disk and receiving the laser beam reflected by the disk, an up-down block arranged movably between a lower position and an upper position, an up-down motor for moving said up-down block up and down, a turntable for supporting the disk and a spindle motor secured to said up-down block and having a driving shaft coupled with said turntable for rotating the turntable, a position detecting device for detecting a position of said up-down block to derive a position signal when the up-down block is driven into the upper position, a rotation detecting device for detecting a rotation of said optical information record disk to derive a rotation signal when the optical information record disk is rotated at a predetermined revolving speed, and a control device for initiating a focus control for moving said objective lens and turntable relative to each

Abstract: To stably perform optical recording and optical reproducing under optimum conditions, in an optical recording medium having a writable recording layer on a substrate and having a maker recording area in which recording is performed by a maker on the recording layer, individual drive control information of the optical recording medium is recorded in the maker recording area, and, in optical recording and optical reproducing, optical recording and optical reproducing are performed by the drive control information under optimum conditions.

Abstract: A drive pulse for writing is generated based on a data pulse signal to be recorded, a light source element is driven with this drive pulse to obtain a beam of light, and this beam of light is irradiated onto an optical recording medium to record the data pulse signal on the optical recording medium. When the drive pulse is generated, a write pulse is generated based on the data pulse signal, and compared with a beam intensity signal representing intensity of the beam of light to optimally control a pulse width of the drive pulse.

Abstract: A calibration processing unit is provided, a reproducing operation of an optical storage medium by a reproducing unit is executed while changing a reproducing magnetic field and a reproducing laser power, a reproducible state is measured, and a set of best values of the reproducing magnetic field and the reproducing laser power which are used in the reproducing unit are determined on the basis of the measurement result. The calibration processing unit increases the reproducing magnetic field in a state where the reproducing laser power is fixed. When the reproducible state is not obtained, the measurement of the reproducible state due to the increase in reproducing magnetic field is repeated while increasing the reproducing laser power step by step. The reproducible state can be also measured while alternately increasing the reproducing laser power and the reproducing magnetic field.

Abstract: A small-sized, inexpensive optical pickup apparatus can be assembled with high accuracy. The optical pickup apparatus has a various-purpose semiconductor laser, an integrated optical assembly for guiding outgoing light to an optical disk and for separating reflected light, a light receiver for receiving light and converting the received light into an electrical signal, and a coupling member for retaining a positional relationship among the various-purpose semiconductor laser, the integrated optical assembly, and the light receiver. By using a various-purpose semiconductor laser, the optical pickup apparatus can be made in a small size at low cost, and can be accurately assembled. The apparatus is also capable of accurately and efficiently detecting the optical power of the various-purpose semiconductor laser.

Abstract: A laser diode (LD) driver and method, in an optical recording and reproduction apparatus, drives an LD by receiving channel control signals to control power levels of a laser signal from the LD including switches turning on and off driving potentials, each switch corresponding to the power level of the laser signal according to the channel control signals. A multiplexer multiplexes driving potentials and outputs a multiplexed signal. A gate determines an operating mode of the optical recording and reproduction apparatus according to the channel control signals. A variable gain amplifier variably amplifies a monitor signal according to the operating mode determined by the gate and outputs an amplified monitor signal. A sample and hold circuit samples and holds the amplified monitor signal and outputs a signal indicative thereof. An analog multiplexer outputs a reference signal corresponding to the power level of the laser signal according to the operating mode determined by the gate.

Abstract: When a migration is predicted and judged of continuous recording and regeneration to an adjacent next optimum condition effective area in the course of data sequential processing for recording or regenerating data continuous in a certain optimum condition effective area, a setting control unit performs optimum condition setting processing (erase, recording, regeneration) of the next optimum condition effective area under the control of an optimum condition setting processing unit, to thereby previously determine the optimum emission power and the optimum magnetic field.

Abstract: A device for recording information on an optical disc so as to improve the recording quality of the information when a recording operation has just started. The recording device includes a luminous element radiating a light for recording information on the optical disc; a radiation intensity controller constantly controlling an intensity of radiation of the light radiated by the luminous element; a constant outputting unit providing a constant energy to the luminous element; a selector selectively selecting one of the outputs of the intensity of radiation controller and the constant outputting unit; wherein, the selector selects the output from the constant outputting unit during a predetermined duration from a starting time of recording the information on the optical disc, and selects the output from the intensity of radiation controller afterward.

Abstract: A method and device for controlling a power of pulsed light is provided, which is emitted by a light source, condensed by a object lens and irradiated to a recording medium for recording information in the recording medium. In order to use the power more efficiently under the limitation of the maximum output of the light source and the maximum efficiency of condensing light in the optical system, the method includes steps of performing test writing with the pulsed light having a fixed bottom power and variable peak power, calculating an optimum average power in accordance with the bottom power and the peak power of the optimum condition obtained by the test writing step, and recalculating the peak power and the bottom power in accordance with the optimum average power so that the peak power is decreased and the bottom power is increased.

Abstract: An optical pickup apparatus is provided with: a light source (20) for emitting a light beam; an optical system (21, 22, 24, 25, 26, 27), which comprises an optical element (24) having an incident surface (24a), to which an AR (Anti-Reflection) coat is not applied and to which the light beam emitted from the light source is inputted obliquely by a predetermined incident angle, for guiding one portion of the emitted light beam transmitted through the incident surface onto an information record medium (32) and guiding a reflection light of one portion of the emitted light beam reflected from the information record medium, and also reflecting another portion of the emitted light beam by the incident surface; a main light detector (30) for receiving the reflection light from the information record medium guided by the optical system and outputting a main detection signal corresponding to record information recorded on the information record medium; a monitor detector (23) for receiving another portion of the emitt

Abstract: In an apparatus for recording information to an optical recording medium, a laser beam is irradiated to and reflected from the medium. A photodetector detects the light quantity of the irradiated or reflected light beam, and the detected laser beam is subjected to the signal processing. Then, a sampler samples it at the timing of a sampling pulse supplied from a sampling pulse generator. Then, a controller controls the laser power according to the sampled laser beam. A pulse timing setting unit sets and adjusts the timing of the sampling pulse by taking into account the response time in the propagation path of the laser beam from the start of the irradiation to the sampling. Thus, the laser power can be monitored correctly, and it can be optimized so as to stably and reliably reproduce an address signal and to generate a servo signal while data is recorded.

Abstract: An optical disk having a plurality of substantially concentric tracks, each of which includes a plurality of segments each comprising a servo area ARs provided with servo pits for giving servo information to a disk drive and a data area ARd. Identification marks SGM, ADM, STM1, STM2 are recorded in the servo area ARs. The identification marks SGM, ADM, STM1, STM2 provide information for identifying the respective segments depending on the recording position in the servo area ARs.

Abstract: A recording power control device is capable of optimizing the recording power of a recording optical beam at every recording position on a DVD-R (recordable) disk while an optical disk drive is recording information on the DVD-R disk with the recording optical beam. Simultaneously with the recording optical beam, the disk drive emits an adjusting optical beam behind the recording optical beam in the direction in which information is recorded. The disk drive has a first photodetector for receiving the reflected recording optical beam and a second photodetector for receiving the reflected adjusting optical beam. The recording power control device is equipped with a laser drive circuit for setting the recording power of the recording optical beam according to an output signal from the second photodetector, which receives the reflected adjusting optical beam.

Abstract: A method and apparatus for controlling an optical output of a laser diode. Writing or erasing optical outputs of a laser diode are controlled during a mirror region interval of a header within an optical disk, under a continuous optical output state of the laser diode. A change in the optical output caused by heat of the laser diode is compensated by comparing the writing and erasing optical outputs with corresponding preset writing and erasing optical output values.

Abstract: An optical reproduction method for reproducing information includes intermittently irradiating light to a moving optical medium, detecting reflected light from the moving optical medium while the light is irradiated intermittently when a moving distance of a light spot of the intermittently irradiated light on the moving optical medium is smaller than a diameter of the light spot, processing information based on the detected reflected light utilizing a differential operation, and obtaining a reproduction signal based on the differential operation.