Abstract: A method and an apparatus for driving an optical recording medium for recording and/or reproducing various information for the optical recording medium, in which the output power ratio of the light source may be reduced for recording and reproduction, for optical recording media of different sorts, or for respective recording surfaces of a multi-layered optical recording medium, so that optimum characteristics may be realized even with use of an easy-to-fabricate light source or a light source with a smaller light output rating.

Abstract: A optical scanning device (1) for scanning an information layer (2) with a radiation beam (25) in a writing mode and a reading mode comprises a radiation source (7) for emitting the beam and an objective lens (10) for converging the beam so as to form a scanning spot (19) in the information layer. The device also includes a scanning spot power switch (20) for switching the size of the cross-section of the beam between a first size at the writing mode and a second, larger size at the reading mode so as to switch the rim intensity of the beam between a first intensity level (Irim,writing) at the writing mode and a second, higher intensity level (Irim,reading) at the reading mode, thereby switching the light power of the scanning spot between a first power level (Pwriting) at the writing mode and a second, lower power level (Preading) at the reading mode.

Abstract: It is an object of the present invention to provide an information recording method for recording information in a data rewritable type optical recording medium having a plurality of information recording layers, which can form recording marks having good shapes.

Abstract: When manufacturing a recording medium, a material layer 12 formed on a substrate 11 that composes the recording medium is exposed to a laser beam in accordance with a recording pattern. The material layer 12 has a predetermined reflectivity for the laser beam 13 so as to produce return light for the laser beam 13. By detecting this return light, the focusing of the laser beam on the material layer is adjusted. By doing so, a laser beam can be easily and accurately focused on a material layer during a process in which a laser beam is shone, in accordance with a recording pattern, onto a material layer formed on a recording medium or a production plate used when manufacturing a recording medium.

Abstract: Based on a recording signal, a recording pulse signal, which includes a top pulse located at a front end portion and having a first magnitude, a last pulse located at a back end portion and having the first magnitude, and an intermediate bias portion located between the top pulse and the last pulse and having a second magnitude, is generated. Based on the recording pulse signal, a light source is controlled, and a laser pulse is irradiated on a recording medium. Recording marks corresponding to the recording signal are formed on the recording medium. In generating the recording pulse signal, when the recording medium is rotationally driven, a position of the top pulse is shifted ahead of a position of the top pulse when the recording medium is rotationally driven at the first rotation speed, when the recording medium is rotationally driven at the second control speed.

Abstract: In order to compensate for so-called clipping effects, it is proposed, in an apparatus for reading from and/or writing to an optical recording medium in which the light power of a laser diode (1) is to be set to a plurality of light power levels,to perform a calibration to a specific light power level (LP2) before the actual regulation of the light power. On account of the calibration, the instantaneous gradient of the characteristic curve which describes the dependence of the laser light power on the laser diode current can be inferred in order, on the basis of this information, to take account f a change—caused, for example, by ageing r clipping effects—in the characteristic curve gradient in the course of the subsequent regulation of the light power of the scanning beam generated by the laser diode (1).

Abstract: A method of adjusting a condition for at least one of a recording operation and a reproducing operation includes the following steps. At least first and second asymmetry values is found. The first asymmetry value is defined based on a first signal combination selected from at least three signals different in cycle from each other. The second asymmetry value is defined based on a second signal combination selected from the at least three signals. The second signal combination is different from the first signal combination. The condition is set with reference to the at least first and second asymmetry values.

Abstract: A disk recording apparatus for recording data to a disk includes: a reading and writing element for emitting a read beam onto the disk to read out recorded data therefrom while emitting a plurality of write beams simultaneously onto the disk to record data thereto in parallel; and a controlling element for controlling where to emit on the disk the plurality of write beams in accordance with the data read out by the reading and writing element.

Abstract: A method of determining a recording power used to record information to an optical disc, includes carrying out test recording which records predetermined data to a predetermined area of the optical disc to determine the recording power, and recording predetermined data with a power equal to or more than the determined recording power to an area adjacent to the predetermined area.

Abstract: A method for arranging conducting lines of a flexible cable in an optical disk drive first confirms the pins having similar functions of all chips on a main board and a sub-board, and uses only one conducting line of the flexible cable to connect these pins. Therefore, the number of the conducting lines of the flexible cable can be reduced.

Abstract: An optical record carrier recording method forms pits and lands by directing a radiation beam (12) onto a recording surface (21) of an optical record carrier (20). The radiation beam for each pit to be recorded is set to at least one write power level (Pw) capable of forming a pit during a write power irradiation period (31) and, for each land between the pits, to at least one bottom power level (P0) incapable of forming a pit during a bottom power irradiation period (51).

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: A disk drive uses a running OPC control recording technique for obtaining an optimum recording power level. The disk drive irradiates an optical disk with an optical spot, detects a front power level and a rear power level of a reflected optical spot, calculates an index of the recorded state of the mark formed by the recording power of the optical spot, and controls the recording power based on the index of the recorded state.

Abstract: The invention relates to a reproduction or recording apparatus for different optical recording media, which differ for example with regard to their storage density, are scanned by different means and have a photodetector arrangement that is jointly used for the different recording media and scanning means, which arrangement provides a photodetector signal which is independent of the absolute light power level of the laser diodes. For generating the photodetector signal which is independent of the absolute light power level of the laser diodes, a switch for changing over the sensitivity of the photodetector is provided, which switch is controlled by the modulator for generating a uniform light power with a laser diode. A connecting line to the basic apparatus and corresponding terminals for controlling the switch are advantageously obviated as a result.

Abstract: A device that records information on an optical disc and a method for recording the information on the optical disc, so as to maintain a constant recording quality when the information is recorded on the optical disc using a constant number of the rotations to control the speed. The recording device includes a linear velocity detector detects a linear velocity which is a velocity of a spot of a light, which is irradiated to record the information on a surface of the optical disc, in a tangential direction of a circumference of the optical disc, and an optical power controller controlling the optical power of the light to record the information on the surface of the optical disc based on the linear velocity detected by the linear velocity detector.

Abstract: An optical recording method and recording apparatus using this method is described in which an optimum write power of a radiation beam in the apparatus is set by writing a series of test patterns on an optical recordable medium, forming a read signal from the patterns, reading a preset value of the derivative of the modulation of the read signal with respect to the write power from the medium, and processing the read signal together with the preset value to derive an optimum value of the write power.

Abstract: An optical disk device in which the laser light power for writing data onto an optical disk is optimized. Test data is written onto an optical disk while laser light power is varied and the laser light power is optimized based on the quality of replayed signals of the test data. The space value of the replayed signal of the test data is detected and, when the space value is a value which should not exist, it is judged that 3T mark period is missing or excessively written and the laser light power in which such a space value is obtained is removed from the candidates for the optimum laser light power. Also, jitter and error rate of the replayed signal are detected. Even when the jitter is at a desirable value, if the error rate is greater than or equal to a predetermined value, the laser light power in which such an error rate is obtained is removed from consideration as a possible optimum laser light power.

Abstract: A method for controlling an optical drive to record data onto a disc. The optical recorder has a pick up head for emitting laser onto the disc to record data onto the disc. The method includes adjusting a write power and a write strategy of the optical drive according to a linear velocity of the disc when passing by the pick up head.

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 signal processing. Then, a sampler samples the laser beam at the timing of a sampling pulse which is 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 the laser power can be optimized so as to stably and reliably reproduce an address signal and to generate a servo signal while data is being recorded.

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: A write-once type optical recording medium is provided, which is low-cost and capable of maintaining the recording and reproducing stability high while enabling the relative ratio of read power to write power to be set high. The high-speed write-once type optical recording medium 10 includes a recording layer 18 that is constituted by laminating first and second subsidiary recording layers 18A and 18B each having one type of metal, for example Al and Sb respectively, as the main component. In the optical recording medium 10 having such constitution, the ratio between write power Pw and read power Pr, Pw/Pr is set to a value in the range of 2.0 to 8.0. When the recording layer 18 is irradiated with laser beam with a wavelength of 200 nm to 450 nm and a write power Pw of 2.5 to 5.

Abstract: An information recording technique for forming a recording mark with a multi-pulse sequence, which is increased by one pulse with an irradiation power Pw for every increase of 2T in a temporal length nT of the recording mark is provided. Particularly, this technique realizes a recording strategy that is simple in its configuration but is capable of improving the consistency of mark shapes in forming the recording marks when the value n of the temporal length nT is an odd number. More specifically, when n is an odd number and n?7, a period from the fall of a first pulse to the fall of a second pulse is set to 2.5T and a period corresponding to a last pulse is set to (2+?1o) T where the value of ?1o is optimized within a range of 0<?1o?1.

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: An optical disk read/write apparatus detects a shift in the tilt during a write operation and corrects it before resuming the write operation. Specifically, when the ROPC control signal detector of the optical disk read/write apparatus controlling the write power determines that the write power has exceeded a predetermined value after a control operation, the optical disk read/write apparatus suspends the write operation through control of the laser power and controls the shift in the tilt with the tilt controller before resuming the write operation.

Abstract: An optical recording medium has a phase-change recording layer containing Sb and Te as essential elements therefor, to which is added at least one element selected from the group consisting of Ag, Au, Cu, Zn, B, Al, Ga, In, Si, Ge, Sn, Pb, N, P, Bi, La, Ce, Gd, and Tb, the recording layer being capable of assuming an amorphous phase changed from a crystalline phase by the application of a laser beam thereto, thereby optically recording information. Recording marks are formed in the recording medium by converting a light emission wave of laser beam into a recording pulse train comprising a plurality of on-pulses and off-pulses, with a recording frequency being continuously changed corresponding to the location of each of the recording marks in the radial direction of said recording medium. A recording apparatus has laser beam driving circuit means, signal generation means, and signal transmission means for achieving the above recording method.

Abstract: A method in which, during an optimal power calibration (OPC) process, an optical disk drive performs a plurality of write tests to an optical disk at a plurality of test powers and measures a corresponding plurality of modulation signal strength values of the optical disk for the plurality of write tests to generate a modulation signal strength versus power curve. The method then determines possible gamma lines corresponding to considered powers, and selects a considered power as a target power of the optical disk drive when a possible gamma line is substantially tangential to the modulation signal strength versus power curve at the considered power. According to the method, powers within a domain of the plurality of test powers are considered until a considered power is selected as the target power for the optical disk.

Abstract: A recording apparatus to record a mark on a recording medium includes an aberration detecting part and an optical power controller. The aberration detecting part detects an aberration signal corresponding to the amount of an aberration contained in a light beam radiated onto a recording surface of the recording medium by using an optical pickup system which includes a light source and an objective lens. The light source emits a light beam having a power to record the mark on the recording medium. The objective lens condenses the light beam to focus the light beam as an optical spot on the recording surface of the recording medium. The optical power controller controls the power output from the light source according to the detected aberration signal, so as to have the light source output an optical power to record the mark, in which a deformation due to the aberration is compensated for, on the recording medium.

Abstract: The present invention provides a data-recordable optical disk device. Test data is recorded in a predetermined area of an optical disk while varying recording power level, and an optimum recording power level is selected based on reproduced signal quality of the test data. When the optimum recording power level does not exceed an allowable recording power level of the laser diode, data is recorded at that optimum recording power level. When the optimum recording power level exceeds the allowable recording power level of the laser diode, the recording strategy is changed to a low-power strategy. A low-power strategy is, for example, a strategy having an increased recording pulse width compared to that of a standard strategy. An optimum recording power level is selected for the low-power strategy, and data is subsequently recorded.

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: A power calibration apparatus identifies a calibration area divided by an EFM frame unit on an optical disc and controls writing by a writing means. According to read out information for test writing written in the optical disc, a first writing power is calculated. By setting the first recording power as an initial value and changing the first recording power by a dense degree through steps corresponding to the number of the calibration areas divided by the EFM frame unit, the apparatus urges writing by the writing means. According to the read out information for the test writing written in the optical disc, a second writing power is calculated.

Abstract: The apparatus records information by irradiating a laser beam onto a recording medium and forming marks on the disc. Prior to the actual recording, the controller performs a test recording in which predetermined test recording data is recorded on the recording medium. In the test, data is recorded by generating a recording pulse signal based on the recording data and thereby driving a light source. While the test recording is performed, the level of a cooling pulse in the recording pulse signal is varied. Then, the test recorded data is reproduced to generate a reproduced signal. A waveform of the reproduced signal is evaluated, and a cooling level that provides a target asymmetry value is set as an optimum cooling level. Thus, the subsequent actual recording can be performed according to the optimum cooling level determined based on characteristics of the recording medium to be used for the actual recording.

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 establish manufacturer-specific test writing parameters for writing of a writable optical storage media in accordance with the media manufacturers, which are experimentally determined and stored into a certain storing unit; determine an optimum writing light power based on the determined optimum writing parameters; and write an input signal into the user's data region of the optical disk.

Abstract: In an optical recording/reproducing method and apparatus of the present invention, a modulation parameter is calculated for each of reproduced data signals, each modulation parameter corresponding to one of respective recording powers. An optimum recording power is determined based on a relationship between the modulation parameters and the recording powers, wherein a sequence of pairs of the modulation parameter and the recording power is selected, a gamma, which defines a ratio of a change of the modulation parameter to a change of the recording power, is calculated for each of the selected pairs, and a target recording power corresponding to the optimum recording power is found based on a function derived from a relationship between the calculated gammas and the respective recording powers, the target recording power causing a value of the function to be equal to zero.

Abstract: An optical recording method for recording mark length-modulated information on a recording medium by using a plurality of recording mark lengths. The optical recording method comprises the steps of: when a time length of one recording mark is denoted nT (T is a reference clock period equal to or less than 25 ns, and n is a natural number equal to or more than 2), (i) dividing the time length of the recording mark nT into ?1T, ?1T, ?1T, ?2T, ?2T, . . . , ?iT, ?iT, . . .

Abstract: An optical disk apparatus records information by irradiating a laser beam from a pickup onto an optical disk. A scanning section scans the laser beam relative to the optical disk. A recording control section controls the scanning section to effect recording of information. A drawing control section is provided for controlling the pickup and the scanning section to effect drawing of a visible image on the optical disk according to image information, such that the laser beam is changed between a first intensity incapable of acting on the optical disk and a second intensity capable of acting on the optical disk. A servo section periodically detects the laser beam reflected back from the optical disk when the laser beam has the first intensity, and servo-controls the irradiating of the laser beam during the drawing of the visible image based on the detection of the laser beam.

Abstract: It is an object of the present invention to provide a method of recording information to an optical recording medium that is suited to achieving high data transfer rates. The optical recording medium according to the present invention comprises a method of recording information to an optical recording medium where information is recorded by forming on the optical recording medium a plurality of recording marks selected from a group consisting of several types of recording marks with different lengths each corresponding to n times (n is a natural number) the clock frequency T, wherein: taking Tr to be the transition time required for a laser beam to rise and Tf to be the transition time required for the laser beam to fall, said recording marks are formed using a laser beam made up of a number of pulses given by nT/(Tr+Tf) or less.

Abstract: An optical carrier is written with a mark representing recorded data, by a sequence of radiation pulses. Additional power levels are introduced in between the cooling power level and the erase power level during the cooling period. This results in a reduced jitter of the written marks.

Abstract: An optical record carrier recording method forms pits and lands by directing a radiation beam (12) onto a recording surface (21) of an optical record carrier (20). The radiation beam for each pit to be recorded is set to at least one write power level (Pw) capable of forming a pit during a write power irradiation period (31) and, for each land between the pits, to at least one bottom power level (P0) incapable of forming a pit during a bottom power irradiation period (51).

Abstract: A laser diode (LD) driver and method of compensating for a bias driving potential of an LD driver according to a change in a power level of a laser signal from an LD in a recording mode include storing the bias driving potential, detecting a change in a bias power level in the laser signal, and compensating the bias driving potential according to the detected change in the bias power level.

Abstract: A signal recording/playback apparatus includes a recording data converter. The recording data converter converts on a data pattern having a large influence on adjacent tracks on an optical disk, and outputs the converted data to an optical pickup. Specifically, by performing a data converting process in which, for a data pattern having a predetermined length of at least consecutive bits having identical values, part of the bits is inverted based on a conversion table, the recording data converter compensates a recording operation. Alternatively, instead of inverting the bits, by controlling the output power and pulse width of a laser, the recording operation is compensated. The signal recording/playback apparatus includes a played-back data converter. In the data playback mode of the signal recording/playback apparatus, the data converted by the recording data converter is identified and decoded into the original data by the played-back data converter. The played-back data converter outputs the original data.

Abstract: A method for automatically controlling output power of a pick-up head. When output power of a pick-up head is to be changed, a first switch is utilized to connect a first input port of a comparator circuit to a supply source, and a second switch is utilized to connect a first signal source to a driver circuit such that the driver circuit will control the output power according to a first signal. When voltage drop between the first input port and a output port of the comparator circuit stabilizes, the first switch is utilized to connect the first input port to a sensor, and the second switch is utilized to connect the output port and the driver circuit such that the driver circuit will control the output power according to a comparative signal.

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: A semiconductor light-emitting device has a semiconductor layer containing Al between a substrate and an active layer containing nitrogen, wherein Al and oxygen are removed from a growth chamber before growing said active layer and a concentration of oxygen incorporated into said active layer together with Al is set to a level such that said semiconductor light-emitting device can perform a continuous laser oscillation at room temperature.

Abstract: A DVD-R recorder according to the invention detects an item of recording speed information (d15) from a DVD-R (30) on which histories of recording speed information, write strategy, and recording power condition are stored. When the decoded item of recording speed information (d15) agrees with a set item of recording speed information (d17), the recorder detects the write strategy (d6) and the recording power condition (d10) corresponding to the decoded item of recording speed information (d15). A recording-pulse-determination section (9) converts a recording pattern (d8) into a recording pulse (d9) according to the write strategy (d6). A recording-power-determination section (12) performs an OPC based on the recording power condition (d10). The recording power condition (d10) may include information specifying that a recording pulse corresponding to the front edge of a recorded mark has a larger recording power than other recording pulses.

Abstract: An optical storage device decreases the influence of return light to the laser light source and prevents an increase of power consumption even if high frequency superimposing is performed. The optical storage device applies drive current, to which a high frequency signal is superimposed, to the laser light source, and reads/writes data from/in the storage medium. The high frequency superimposing is set to OFF as a default to save power consumption, and high frequency superimposing is turned ON only when it is judged that servo is unstable, and high frequency superimposing is turned OFF when it is judged that servo is stable.

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 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 apparatus for controlling the power of a laser diode, which can prevent fluctuation in the laser power of the laser diode at a record/playback area of an optical disc. The apparatus for controlling the power of the laser diode includes a controller which controls an automatic power control of the laser diode (APC controller), interposed between an up/down counter and a laser diode driver, the APC controller latching the output of the up/down counter in synchronism with a periodic synchronization signal, and outputting the latch result to the laser diode driver. Therefore, the power level of the laser diode can be periodically controlled according to subdivided control modes, so that the laser power level remains resilient to external noise, compared to a continuous control operation through the entire mode.

Abstract: A semiconductor laser drive circuit of the present invention reduces the number of wires, solves the out-of-timing problem of pulses due to differences in wire length, and emit short light pulses at a high transfer rate. A common emitter circuit (18) converts a voltage signal (J1) input at an input port (18a) into a current signal and, when reading information, adds the current signal to a signal output from a high-frequency oscillator circuit (20). High frequency components of the current signal converted from the voltage signal (J1) within a bandwidth of a transistor (Q6) are boosted. Degradation of the output signal of the high-frequency oscillator circuit (20) is kept at a minimum by a common base circuit including the transistor (Q6). A current switch circuit (16) cuts off or lets through the output current of a current mirror circuit (12).