Abstract: An optical disk device capable of data recording. A tracking error signal is generated from return light from an optical disk, and the tracking error signal to which a tracking offset signal is further added is supplied to a tracking servo circuit. A tracking offset signal in accordance with the driving current when recording data is determined based on the relationship between the driving current of the laser diode and the optimum tracking offset. Tracking control is performed using a fixed tracking offset signal when reproducing data and using a tracking offset signal which is variable in accordance with the driving current when recording data.

Abstract: Disclosed is an optimal recording method for optical recording media which is capable of recording information about optimum recording conditions on an optical recording medium in order to allow a subsequent recording of data at an optimum recording power, based on the recorded optimum recording condition information. In this method, test data is recorded to allow derivation of an optimum power value based on reproduction characteristics of the test data. An intrinsic recorder ID information of an optical recording/reproducing apparatus, used to record data on the optical recording medium, and information about the record speed of the apparatus are recorded, along with the derived optimum power value, onto the count area of the optical recording medium or respective lead-in areas of sessions. The apparatus reads out the recorded optimum recording condition information when data is subsequently recorded onto the optical recording medium.

Abstract: A method for evaluating the aging level of a component includes measuring values of the elapsed time in operation of the component (tm,i), at least one entity (Im,i) indicative of the aging of the component, and the temperature (Tm,i) of the component, and processing the values measured as a function of a reference temperature (Tref) to produce corresponding normalized reference values (tref,i; Im,i) representative of virtual operation of the component at said reference temperature (Tref). An updated prediction model for the at least one entity over time is generated from the reference values (tref,i; Im,i). A predicted value (Ifit) for the at least one entity at a given time obtained by means of the prediction model is compared with an aging threshold. An aging warning signal is generated if the comparison indicates deviation of the predicted value (Ifit) beyond an acceptable range.

Abstract: A disk recording-playback device including a laser drive circuit for feeding a drive signal to an optical head and adjusting the power of a laser beam irradiated by the optical head, an error correcting circuit for detecting an error rate of a reproduced signal, and a system controller for controlling operation of the laser drive circuit for signal reproduction and signal recording based on the output of the error correcting circuit. The system controller successively sets the laser powers to at least three different values, obtains evaluation data for each laser power, approximates the relationships between the laser powers and the evaluation data to a quadratic curve, whereby an optimum laser power is derived corresponding to a vertex of the quadratic curve. Accordingly the optimum reproduction power and recording power are set, to thereby record and reproduce signals with high accuracy.

Abstract: A laser diode (LD) driver and method, in an optical recording and reproduction apparatus, to drive an LD determines a type of a loaded recording medium; and sets driving potentials corresponding to power levels of a laser signal output from the LD according to the determined type of the recording medium.

Abstract: The present invention provides a disk playback device comprising a laser drive circuit 15 for feeding a drive signal to an optical head 4 and adjusting the power of a laser beam irradiated by the optical head 4, an error correcting circuit 11 for detecting an error rate of a reproduced signal, and a system controller 10 for controlling operation of the laser drive circuit for signal reproduction and signal recording based on the output of the error correction circuit 11. The system controller 10 retrieves one limit value of two limit values of a reproduction power wherein the error rate is not beyond a prescribed value, and calculates an optimum reproduction power based on the one limit value retrieved. Accordingly it is possible to move to signal reproduction in a short period of time and to reproduce signals with high accuracy by setting the optimum reproduction power.

Abstract: An optical scanning device for scanning an optical record carrier includes a radiation source and a beam splitter arranged to pass a first portion of the source beam to the record carrier, and a second portion to an intensity sensor. A signal detector is arranged in the path of the beam reflected by the record carrier. False radiation reflected by the signal detector can be prevented from reaching the intensity sensor by tilting the signal detector. A polarization filter may be arranged in front of the intensity sensor to prevent false radiation reflected by the radiation source and by the signal detector from reaching the intensity sensor.

Abstract: A photodetector and optical pickup device which comprises: a monitoring photodetection element (photodiode) 23 for receiving laser beams having different wavelengths from laser light sources; a light source-discriminating photoreceiver 24 represented by a photodiode (240) and a wavelength selection filter (241) for discriminating the wavelength spectra of the laser light sources; and a sensitivity regulation circuit (25) for regulating the sensitivity of the monitoring photodetection element 23 in response to the light source-discriminating photoreceiver 24.

Abstract: An error detector circuit compares a value corresponding to a laser power supplied from a monitor diode of an optical pickup with a value representative of a target laser power, and outputs an error from the target value to a change-over switch. The change-over switch selects one of low-pass filters used for CAV recording and CLV recording. The low-pass filter used for CAV recording has a larger time constant than that of the low-pass filter used for CLV recording. The servo gain of a servo loop during the CAV recording is therefore set smaller than that of a servo loop during the CLV recording. A change in the laser power becomes gentle.

Abstract: A method and an apparatus that automatically controls the optimum output of a laser diode. The apparatus automatically controls the output of a laser diode based on the results of a comparison between the current power value of an optical signal output from a laser diode and a basic power value. The apparatus includes: a sampler to sample the current power value output from the laser diode; a register unit to store the output of the sampler; a basic register unit to store a basic value; an operation unit to output a target output value applied to the laser diode based on the current power value and the basic power value stored in the register unit and the basic register unit; and a pulse generator to generate a control signal that controls the storing timing of the register unit based on recording data to be recorded by the laser diode.

Abstract: An apparatus for detecting abnormal states which prevents damage to a laser diode or data recorded on a disc and swiftly correcting the abnormal state. An overflow/underflow detector detects whether overflow or underflow of the laser diode occurs, by comparing a laser diode output power control value, which is output from the laser diode output power control circuit, with an overflow setting value and an underflow setting value. A mode switch switches an operation mode of the laser diode output power control circuit from a recording mode to a reproducing mode, in response to the detection result of the overflow/underflow detector.

Abstract: A method for detecting a current through a pick-up head in an optical storage device. An output value is first set and a root-mean-square value corresponding to the current is further obtained. Next, compute a new value according to the root-mean-square value and a preset value, wherein the preset value is expressed in exponential form and related to an allowable current and a maximum current of the pick-up head. The output value is set as the new value. The pick-up head is shut down if the output value is greater than a threshold value within a sampling number, else repeating the step of obtaining the root-mean-square value.

Abstract: According to the present invention, maintenance data about a plurality of distribution terminal devices which are different from each other in frequency with which they are in use and circumstances under which they are in use are transmitted to a host computer, whereby a lifetime of a semiconductor laser can be predicted and an occurrence of a trouble can be detected without receiving information from a user or shops in which the distribution terminal devices are installed.

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: An information recording device for writing information in a circumferential direction of a disk-type recording medium, with a substantially constant linear density.

Abstract: An optical storage system includes a pickup head for picking up data from a storage medium. Firstly, the maxima of a tracking error signal and runout are obtained in a calibration procedure in a close loop formed by an optical pickup head, a pre-amplifier, a compensator, a band-pass filter and a maximum detector. A calibration factor is then defined and derived by using the obtained maxima and nominal factors of a power amplifier and the optical pickup head of the optical storage system. The path formed by the series-connected band-pass filter and maximum detector is then disabled, while the calculated calibration factor is then stored in the compensator. The optical storage system may operate in a close loop formed by the optical pick head, pre-amplifier, compensator, a power amplifier under a normal operation procedure so that the optical storage system may record or read data onto/from an optical disc under the compensation provided by the calibration factor.

Abstract: Methods and systems for write compensation for optimizing the performance of a data storage or communication channel are disclosed. In one embodiment, a method comprises determining channel sensitivity to modifications in write signal parameters, detecting systematic errors in a read signal recovered from data written with a first set of write parameters, and adjusting the write signal parameters by an amount determined from the channel sensitivity such that the systematic errors are reduced when data are written with the adjusted write parameters.

Abstract: An optical disk using both grooves and lands as a recording track is provided with {circle around (1)} a data area for recording/reproducing data and {circle around (2)} DMAs (Data Management Areas) for managing a defective sector in the data area. The DMAs include four DMAs A–D all formed on the lands. The DMA B(D) is formed behind the ending sector of the DMA A(C). This arrangement realizes a DMA format having high resistance to defects and improving a processing rate. Consequently, highly reliable optical disk and optical disk apparatus can be provided.

Abstract: An information recording method including irradiating a phase change recording layer of an optical recording medium with either a multi-pulse laser light train having a recording power of Pw or laser light having an erasing power Pe to record a mark having a length nT in the recording layer, wherein n is an integer of from 3 to 14 and T represents a clock cycle, wherein the multi-pulse laser light train has a constitution such that a heating pulse and a cooling pulse are alternated and the number of heating pulses and the number of cooling pulses each increases by 1 when n increases by 2, and wherein when n is from 6 to 14, the last heating pulse and last cooling pulse have a pulse width of from 0.5T to 0.9T and from 0.7T to 1.5T, respectively.

Abstract: A method and system for optimizing energy consumption during data read/write operations in a disk-based memory system is provided. The method includes the steps of reading a data clip length, Ls and determining an available energy-optimum recordable track segment.

Abstract: An apparatus for detecting abnormal states which prevents damage to a laser diode or data recorded on a disc and swiftly correcting the abnormal state. An overflow/underflow detector detects whether overflow or underflow of the laser diode occurs, by comparing a laser diode output power control value, which is output from the laser diode output power control circuit, with an overflow setting value and an underflow setting value. A mode switch switches an operation mode of the laser diode output power control circuit from a recording mode to a reproducing mode, in response to the detection result of the overflow/underflow detector.

Abstract: Because a series of data is recorded continuously, the recording quality of data recorded in course of recording cannot be evaluated. Accordingly, the laser output cannot be controlled properly and there are a deterioration and dispersion of the recording quality. Further, when the recording lasts for a long time, the temperature in the vicinity of laser rises due to the heat from the inside of a disc drive and the recording quality is deteriorated. To solve this, a series of data to be recorded is split and recording is made intermittently in a split data unit. The recording quality is evaluated by reproducing the data recorded nearby before each split data is recorded using a duration and control is performed by reflecting the evaluation result in the laser output so that the recording quality can be maintained satisfactorily over a series of the whole data to be recorded.

Abstract: An optical disk drive has a pick-up head for emitting laser beams, and an analog front-end circuit controlled by a microprocessor for controlling the operation of the pick-up head. An automatic control method for generating stable laser power of the optical disk drive includes getting a power reference function measured by a fixed quantity of optical disk sample drives, establishing the relationship between the laser power control signal of pick-up head from the analog front-end circuit by the microprocessor, and calculating the difference amount from a feedback signal minus a reference voltage on pick-up head side to generate a first function. When the analog front-end circuit receives this feedback signal, this method will be enabled automatically and adjust the first function of the laser power control signal to approach the reference function so as to adjust the intensity of the laser power generated by the pick-up head.

Abstract: An information recording apparatus that records information with a substantially constant linear density in a circumferential direction of a recording medium having a disk shape, includes variable velocity recording control means, recording power modification means, recording power storage means, and initial recording power value setting means.

Abstract: A power control circuit for an optical information recording device is disclosed. A power sampling signal from a photodiode is transmitted to a peal envelope acquiring circuit and a bottom envelope acquiring circuit and then sampled and held, which is fed-back to a laser diode driving circuit. The laser diode driving circuit alters a driving signal emitted to the laser diode according to the fed-back signal to adjust the power of the optical signal emitted from the laser diode. Therefore, cost is reduced and the power control circuit is particularly suitable for high-speed recordable optical disk drive.

Abstract: The present invention relates to an optical head unit and an optical disk unit using the optical head unit. The head unit includes a wavefront transforming optical element control unit to controls a wavefront transforming optical element so as not to transform wavefront of a light beam focused on a recording layer by a focusing unit due to the thickness error of a light transmission layer positioned between the recording layer and the focusing unit based on an electrical signal outputted from a first light detector, and an output control unit that controls light amount of a light beam radiated by a light emitting unit based on the magnitude of the electrical signal outputted from the light detector.

Abstract: Light emitted from a laser is divided into two light waves so that the ratio of the power of one light wave to the power of the other will be appropriate. The resultant light waves are irradiated to the same track on a medium. The preceding spot is used for erasure, and modulated so that the same pattern as the one formed with a recording pulse will be formed. The high-power component of the modulated light of the erasing spot causes the temperature of a recording layer to be equal to or higher than the melting point. The medium-power component of the modulated light forms a crystallizing temperature area on the recording layer. A liquid crystal diffraction grating is used to divide power, and a power division ratio is variable and controllable.

Abstract: An optical recording apparatus includes a light source driving unit for driving a light source; an emitted light power detecting unit for detecting an emitted light power; a temperature detecting unit for detecting a temperature of the light source; a light power control unit for adjusting a driving current of the light source such that a change rate of an emitted light power detection value fall within a predetermined range; and a detection value storing unit for storing a driving current adjustment value in association with a temperature detection value. The light power control unit adjusts the driving current value of the light source based on an stored detection value when the temperature detection value is within a range of temperature detection values already stored in the detection value storing unit.

Abstract: Disclosed is a lens for light collection for total reflection for a front monitor photodiode (PD) in an optical pick-up device. The optical pick-up device includes a light source provided with a holographic unit adapted to diffract a light beam, an optical disc arranged in front of the light source and adapted to allow data to be written thereof or to be read therefrom, a monitor photodiode arranged in front of the light source in a diagonal direction with respect to the light source, the monitor photodiode serving to monitor a laser power of the light source, and a lens for light collection arranged between the light source and the monitor photodiode and adapted to converge a first-order diffracted beam outputted from the holographic unit and to apply the converged first-order diffracted beam to the monitor photodiode.

Abstract: A method and related apparatus for storing program code and optimized power calibration (OPC) data in the same non-volatile memory is provided. The method is used for accessing OPC data from an optical discrecorder. The optical disc recorder is capable of obtaining OPC data of an optical disc by executing an optimized power calibrating process so as to record data onto the optical disc. The optical disc recorder has a first memory with a program code being stored therein and a second memory. The method includes registering the program code in the second memory, and writing the OPC data of the optical disc to the first memory according to the program code registered in the second memory.

Abstract: In an optical disk drive, an OPC is performed prior to a start of recording of an optical disk by accessing a power calibration area of the disk with a light beam emitted by a light source while the disk is rotated at a constant linear velocity. An optimum recording power for the light source during the recording is determined based on results of the OPC. A highest linear velocity of linear velocities is changed to a next highest linear velocity for a controlled velocity of a disk rotation device during a subsequent OPC. It is detected whether the OPC and the determination are normally performed after one of the linear velocities is set. The controlled velocity during the recording is set to an angular velocity corresponding to the one of the linear velocities at which the OPC and the determination are normally performed.

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: The invention is to provide a method for determining a recording power of a radiation beam for recording information onto a recording medium operated at a user-desired speed. According to a preferred embodiment of the method of the invention, under operation of multiple of test speeds in turn, multiple of optimum recording powers which each corresponds to one of the test speeds are determined, respectively. Then, a function of speed is generated by fitting the corresponding optimum recording powers vs. the test speeds. The recording power for the user-desired speed is calculated by applying the user-desired speed in the function of speed.

Abstract: An optical recording method and apparatus in which a main light spot and a secondary light spot at a predetermined distance ahead of the main light spot in a track direction along which an optical disc rotates are formed on an optical disc. When a mark is recorded by the main light spot in response to a recording signal, an existing mark is partially erased by the secondary light spot during a recording signal period and then completely erased by the main light spot during an erasing signal period. Accordingly, an optimal erasing ratio can be obtained even during fast erasing. Therefore, in the present invention, a mark can be fast recorded on the optical disc, and fast mark recording can be achieved in an optical disc having no special crystallization accelerating layers for accelerating erasing.

Abstract: A magneto-optical recording medium processing apparatus of the present invention limits, via a predetermined current limiting means, the bias current applied to a bias coil during seek, when a seek current is applied to a carriage. In accordance therewith, it is possible to reduce the peak of the sum current, which is the total of the seek current and the bias current, and the current consumption of the entire apparatus can also be curbed. Current limiting means, for example, sets a bias current that is smaller than the specified value of the bias current required at media access time, and sets a bias current value such that the total of the seek current and bias current does not exceed an allowable current.

Abstract: With an object of executing excellent finishing processing when information is recorded to a rewritable type record medium or a write once type record medium, the finishing processing is switched by whether a kind of a medium for recording information is the rewritable type record medium or the write once type record medium and a method of executing the finishing processing is switched based on a state of supplying power.

Abstract: An optical recording medium and method for recording/reproducing data on/from the optical recording medium having an optimum recording condition information, are provided. The method includes reading out a reference recording condition recorded on a specific area of the optical recording medium; recording test data while varying a recording condition with respect to the reference recording condition; determining an optimum recording power based on reproduction characteristics of the test data; and recording a recoding condition data including the optimum recording power, recording speed and write strategy type to be used or used to record data, on a specific area of the optical recording medium.

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: An optical disc system includes a disc recording unit for recording an information signal on an optical disc by switching irradiation power of laser light to be applied to the optical disc in accordance with the information signal. The disc recording unit includes a semiconductor laser; a laser-power controlling circuit for outputting a laser-driving-current instruction signal; a recording-pulse generating circuit for outputting a laser-modulation timing pulse; a laser driving circuit for generating a laser driving current in accordance with the laser-driving-current instruction signal and the laser-modulation timing pulse; and a correction-data storage for storing as correction data the shift between the laser-modulation timing pulse and the pulse position of the laser driving current.

Abstract: An information-recording method and an information-recording medium which make it possible to improve overwrite characteristics in the high speed recording, especially archival overwrite characteristics for overwriting information after retaining the medium in a high temperature environment for a certain period of time, and an information-recording apparatus based on the use of the same are provided.

Abstract: An image information detecting cassette accommodating an image information detecting section capable of reducing its power consumption when not used. When the handle of the cassette is gripped by the operator for carrying, the handle grip signal is outputted from the handle grip detecting section. If the readout signal from the scan/readout section, X-ray ready signal from the external system controller, and release signal from the release switch are not outputted, that is, when the cassette is carried and not used, it is determined to be the out-of-use state by the out-of-use determining means. The low power consumption mode is set by the control section, and the power supply to the image information detecting section, reading light emitting section, detecting section driving section, nonvolatile memory, X-ray buzzer, and matrix indicator is discontinued by the power supply suppressing section.

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: An optical pickup includes: a first light module which records information on and/or reproduces information from a first optical recording medium having a first format, radiates a first beam having a first wavelength, and receives the first beam reflected from the first optical recording medium to detect an information signal and an error signal; a second light module which records information on and/or reproduces information from a second optical recording medium having a second format different from the first, radiates a second beam having a second wavelength different from the first, and receives the second beam reflected from the second optical recording medium to detect an information signal and an error signal; a beam splitter disposed along paths of the first and second beams and which changes the paths of the first and second beams; and an objective lens which condenses the first and second light beams to form a light spot on the first and second optical recording media, respectively.

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 storage device protection system has a disk for storing data, the disk including a disk medium and a buffer for writing data to the disk medium. The device includes: a detecting unit for detecting an operation to cut off a main power supply of the device; an access suspending unit for suspending access to the hard disk when the detecting unit detects the operation; a writing unit for writing data in the buffer to the disk medium when the detecting unit detects the operation; and a power cutoff unit for cutting off the main power supply after the writing operation of the medium writing unit.

Abstract: An apparatus for detecting abnormal states which prevents damage to a laser diode or data recorded on a disc and swiftly correcting the abnormal state. An overflow/underflow detector detects whether overflow or underflow of the laser diode occurs, by comparing a laser diode output power control value, which is output from the laser diode output power control circuit, with an overflow setting value and an underflow setting value. A mode switch switches an operation mode of the laser diode output power control circuit from a recording mode to a reproducing mode, in response to the detection result of the overflow/underflow detector.

Abstract: A reproduction method for a multi-level optical recording medium according to the present invention rotates an optical recording medium, on which recording data has been recorded according to a multi-level recording method which sets several levels for light reflectivity of virtual recording cells, emits a reproduction laser beam towards the optical recording medium, and reproduces the recording data based on an electric signal generated in accordance with a received level of reflected light, the method setting the emission power of the reproduction laser beam in a range of 1.0 mW to 2.5 mW inclusive when the optical recording medium is rotated at a linear velocity in a range of 9 m/s to 25 m/s inclusive. By doing so, it is possible to improve the read accuracy for recording data while suppressing the reproduction deterioration of the optical recording medium to a level where deterioration effectively does not occur.

Abstract: A data recording apparatus includes a laser diode applying light to a recording medium to record data, a front monitor diode detecting the intensity of light emitted from the laser diode, a switch device for switching to the lowpass filter in the operating state during the time period over which a signal of 14T mark is recorded, a lowpass filter for receiving a signal which is outputted from a front monitor diode, and a sampling/holding unit sampling the output signal which is outputted from the lowpass filter. The intensity of light emitted from the laser diode on the output signal sampled by the sampling/holding unit.

Abstract: A laser driving apparatus for a light source of an optical head apparatus includes a laser, a laser driving circuit, and a radio frequency current generation circuit for generating a radio frequency current to be superimposed on the drive current. The laser driving apparatus further includes a current monitor circuit, an optical detector for detecting an optical output of the laser; a selection circuit for selecting either of non-superimposing or superimposing the radio frequency current on the drive current, an APC circuit for controlling the optical output of the laser at a constant level, and a control circuit. The control circuit controls the amplitude of the radio frequency current on the basis of current values of the drive current on non-superimposing and superimposing or detection values of the optical output of the laser on non-superimposing and superimposing.

Abstract: A means for measuring the temperature in the surroundings of a semiconductor laser is provided and, if the temperature is not above a certain level, power correction is performed at high speed by linearly approximating the I-H characteristic according to one item out of reproduction power and multi-pulse recording power, or if the temperature is higher, accurate power correction of the semiconductor laser is accomplished by detecting a plurality of items out of reproduction power and multi-pulse recording power.