Abstract: The present invention with an optical disk drive controller and an optical pickup head connected together by a flexible cable is described. The device includes a delay adjusting module located within the first module for delaying a first signal by an amount specified by a calibration signal. The first module transmits the delayed first signal and a second signal through a first signal channel and a second signal channel, respectively, to the second module of the optical pickup head, a monitoring module located within the optical pickup head for receiving and reshaping the delayed first signal and the second signal so as to generate a monitor signal. A calibration signal-generating module is located within the optical disk drive controller for receiving the monitor signal so as to generate the calibration signal.

Abstract: The present invention provides a device and method of polynomial power control for optical drives, which is capable of controlling the laser power discharged from the optical pickup head basing on a quadratic curve fitted on a profile of constant linear velocity values and laser powers of optical pickup head. In addition, the present invention can prevent the burning failure caused by the track width of DVD disc is narrower than that of VCD disc.

Abstract: An optical recording and reproducing apparatus and a method for determining a write strategy thereof, includes a pickup part to record record data by irradiating a light on an optical disc, a driving part to operate the pickup part to irradiate the light corresponding to a predetermined optical parameter, an optical parameter variation part to vary the parameter within a predetermined variation range by a certain unit and to output the parameter to the driving part, a parameter determination factor measurement part to measure a parameter determination factor based on signals output from the pickup part, and a control part to determine a middle point between a maximum point and a minimum point of the optical parameter, within a range where the measured parameter determination factor does not exceed a reference value, as a final parameter. Accordingly, an optimal write strategy, in which the optical determination factor does not exceed the reference value, may be determined.

Abstract: A method for optimizing write parameters of an optical storage medium is provided. The method is adapted for a recording device using the optical storage medium. The method includes loading the optical storage medium having a test area into the recording device, determining a combination of an original write strategy and an original write power according to the optical storage medium, writing test data into the test area with the combination of the original write strategy and the original write power for dynamically adjusting the combination of the original write strategy and the original write power to obtain a combination of an optimal write strategy and an optimal write power, and writing data into the optical storage medium with the combination of the optimal write strategy and the optimal write power.

Abstract: The invention provides an integrated photo monitor circuit (12), particularly an integrated photo monitor circuit (12) for CD and DVD applications, comprising a photo detector (14), an amplifier (16) for amplifying an output signal of said photo detector (14), and sampling circuitry (18) for sampling an output signal of said amplifier (16). The invention further provides an optical pickup unit (10), particularly an optical pickup unit (10) for CD and DVD applications, comprising means (20, 22) for emitting light, and means (12) for generating a sampled feedback signal (40) correlated to the output power of said means (20, 22) for emitting light and intended to be evaluated for controlling said output power of said means (20, 22) for emitting light.

Abstract: The present invention is described for compensating a signal which is transmitted by a transmitting module of the optical disk drive controller through a signal channel and received and reshaped by a receiving module of the optical pickup head to calibrate the duty cycle distortion occurred. The claimed method has the steps of providing a periodic test signal, and then delaying the periodic test signal to form an adjusted test signal and adjusting a delay of an edge between the periodic test signal and the adjusted test signal instructed by a calibration signal. Afterward, the method further has the steps of transmitting the adjusted test signal to the receiving module through the signal channel, and receiving and reshaping the adjusted test signal to form a received signal, and then generating a monitor signal, finally, the method has a step of generating the calibration signal in accordance with the monitor signal.

Abstract: An optical recording medium allowing data to be recorded on, erased from, and reproduced from, and storing information about power levels of an erase pulse. The recorded erase pattern information may include information about power levels of first and last pulses of an erase pattern for erasing data. The first and last pulses of the erase pattern can be differently set depending on the differing kind of recording layer or layers of a disk or differing kinds of disks and recorded in a reproducible only area or rewritable area of the optical recording medium. Thus, by presetting the appropriate erase power levels, the time required for selecting an optimal erase power for the optical recording medium can be considerably reduced.

Abstract: A method for performing optimal recording power calibration (OPC) on a recording medium, such as a DVD-RW, is characterized by flagging the address of the last test data. The method enables a recording position of the last test data to be quickly retrieved by recording position information of a power calibration area, in which the last test data is recorded, and indication information (such as a flag bit) indicating the recording position information is the last test data, in a specific area of the recording medium, such as the second field (field 1) of the format 1 RMD (recording management data). Such a method shortens the processing time prior to the OPC, and does not require the recorder to employ registers to determine the address of the last test data.

Abstract: An automatic power calibration apparatus for optical recording devices and a method therefore.

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 system and method are disclosed for providing a gain control signal for a multilevel read signal. In one embodiment, maximum automatic gain control marks are periodically inserted amongst a series of data fields. The automatic gain control marks include a series of high level marks such that the maximum signal detected in the interior portion of each maximum automatic gain control mark is not reduced by intersymbol interference. Minimum automatic gain control marks are also periodically inserted amongst a series of data fields. The automatic gain control marks include a series of high level marks such that the maximum signal detected in the interior portion of each minimum automatic gain control mark is not reduced by intersymbol interference. In another embodiment, multilevel signals are encoded to facilitate automatic gain control. The effect of a plurality of candidate merge symbols on the residual running total power associated with a current data block is determined.

Abstract: In order to make it possible to reproduce information recorded on an optical recording medium without causing deterioration in the information, a semiconductor laser driving device include a semiconductor laser, a photodetecting element for receiving a part of light emitted from the semiconductor laser and converting the part of light into an electric signal corresponding to a light amount; a laser driving circuit for inputting a driving signal into the semiconductor laser in such a manner that an average value of the electric signal coincides with a given target value, and a high-frequency superimposing control section for controlling an amplitude of the high-frequency signal. The high-frequency superimposing control section controls the amplitude in such a manner that a peak-to-average ratio that is a ratio of a peak value of the electric signal with respect to the average value of the electric signal does not increase above a given reference value.

Abstract: A compatible optical pickup, including first and second light sources for emitting lights with different wavelengths and first and second photodetectors for detecting an information signal and/or an error signal, and a method of detecting the amount of output light using the compatible optical pickup. The first and second photodetectors monitor the amount of light output from the second and first light sources respectively such that no extra front photodetectors are required. Thus, the number of optical component parts included in the optical pickup can be reduced, thereby lowering the manufacturing costs for the optical pickup. Also, there is no need to secure a space in a base where a front photodetector is to be installed, so the base is simplified. Thus, inferior moldings are reduced, and the durability of a mold can be prolonged.

Abstract: If a failure is detected during operation of information recording in an optical disc apparatus, the optical disc apparatus stops the recording operation, changes the number of rotations of the optical disc to a low-speed value, seeks a selected recording region, performs OPC processing and trial write operation, measures a ? value as a result of the trial write operation, calculates optimal recording power based on the difference between the measured ? value and a target ? value and recording power set in the OPC processing, and starts the operation of information recording with the selected number of rotations for low-speed operation by use of the optimal recording power.

Abstract: In a DVD-R on which information is to be recorded by an information recording apparatus, prior to the recording of the information therein, there are recorded in advance at least identification information for identifying the information recording apparatus for recording the information onto the DVD-R, and recording parameter information containing optimization information for optimizing a recording state in the record processing executed by the information recording apparatus specified by the identification information. Furthermore, the information recording apparatus reads the recording parameter information at the execution of record processing to use it for the record processing.

Abstract: An optical recording medium allowing data to be recorded on, erased from, and reproduced from, and storing information about power levels of an erase pulse. The recorded erase pattern information may include information about power levels of first and last pulses of an erase pattern for erasing data. The first and last pulses of the erase pattern can be differently set depending on the differing kind of recording layer or layers of a disk or differing kinds of disks and recorded in a reproducible only area or rewritable area of the optical recording medium. Thus, by presetting the appropriate erase power levels, the time required for selecting an optimal erase power for the optical recording medium can be considerably reduced.

Abstract: In a laser-power control method, a power of laser light emitted from a laser-light emitting element and a driving current for driving the laser-light emitting element are detected. An approximate expression indicating a driving-current to light-power characteristic of the laser-light emitting element is updated on the basis of the detected light power and the detected driving current while sequentially increasing accuracy. A command driving current corresponding to a target light power is calculated by using the updated approximate expression. The laser-light emitting element is driven on the basis of the calculated command driving current so as to output the target light power.

Abstract: An information recording apparatus is provided with: a recording device for recording information into recording areas of an information recording medium by irradiating laser light; a reference-output-value holding device for holding a reference-output-value of the laser light for recording the information into the recording areas; an estimating device for estimating an output value of the laser light which was irradiated in the past in an already-recorded-area in which the information is already recorded; and a controlling device for controlling said recording device to irradiate the laser light onto the already-recorded-area with an output value larger than the reference output value if the estimated output value is larger than the reference output value.

Abstract: A driver for driving a light generator for generating light, comprising a digitalto-analog converter (DAC) having a data input, a data output for generating an analog signal, a first multiplexer (MUX1) for cyclic selection of a number of data levels corresponding to desired intensity levels of the light and for coupling the data levels to the data input; a de multiplexer (DE-MUX) synchronized with the first multiplexer (MUX1) for de-multiplexing the analog signal into a set of analog signals; memory means for temporarily storing the set of analog signals; and a second multiplexer (MUX2) for selection of the stored set of analog signals and for generating a drive signal (IL) for the light generator. The memory means is preferably implemented by a set of capacitors (C1-C8). Usually, for instance in an optical disc drive, the light generator is implemented by a laser (Ls).

Abstract: The invention relates to a method and a device for recording an information signal 10 in a phase change layer of a recording medium. A mark is recorded by a sequence 13 of write pulses and previous marks between the marks to be recorded are erased by a sequence of erase pulses 14. De bias power level 191, 192 between the erase pulses is made dependent on the recording speed, thus obtaining low jitter of the recorded marks and at the same time preventing thermal cross write during erase.

Abstract: A recording condition determining method is disclosed for realizing high quality recording at high speed while preventing the degradation of a light source. Specifically, a determination is made as to whether an optimal recording power obtained through OPC or running OPC exceeds a predetermined threshold value, and if it is determined that the optimal recording power exceeds the threshold value, a choice is selected out of multiple choices including the choice of not changing the optimal recording power based on a predetermined selection criterion. Then, a recording condition is established based on the selected choice. By setting the selection criterion so that the choice of not changing the optimal recording power is selected when damage to the light source is expected to be minimal, recording may be performed without lowering the recording speed even when the optimal recording power exceeds the threshold value.

Abstract: An optical recording medium allowing data to be recorded on, erased from, and reproduced from, and storing information about power levels of an erase pulse. The recorded erase pattern information may include information about power levels of first and last pulses of an erase pattern for erasing data. The first and last pulses of the erase pattern can be differently set depending on the differing kind of recording layer or layers of a disk or differing kinds of disks and recorded in a reproducible only area or rewritable area of the optical recording medium. Thus, by presetting the appropriate erase power levels, the time required for selecting an optimal erase power for the optical recording medium can be considerably reduced.

Abstract: In a rewritable compact disc having a wobble groove on a substrate, crystal and amorphous states of a phase-change recording layer are an unrecorded/erased state and a recorded state, respectively. When the recording layer is exposed to recording light, amorphous marks assuming the recorded state are formed. At any of 2-, 4- and 8-times velocities with respect to a reference velocity (1-times velocity) whose linear velocity is 1.2–1.4 m/s, modulation m11 of a recorded signal when the recording light of approximately 780 nm in wavelength irradiates the recording layer via an optical system with NA=0.5 or 0.55 is 60–80%. A topmost level Rtop of reflectivity of the eye pattern of the recorded signal during retrieving at the 1-times velocity is 15–25%, and a jitter of the individual length of marks and inter-mark spaces during retrieving at 1-times velocity is 35 ns or less.

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: In order to compute a set value for a laser driver circuit for obtaining laser light having a predetermined irradiation power by using a calibration coefficient indicating manufacturing errors. In an optical disc device including a laser driver circuit according to the present invention, a laser diode emits laser light, a front monitor photo diode receives the emitted laser light to generate a reception light signal, an APC unit of the laser driver circuit compares the thus generated reception light signal with a target value related to the predetermined irradiation power previously set in the laser light to be emitted, a drive of the laser diode is controlled to match the signal to the target value, and a CPU uses at least one calibration coefficient to compute the set value for matching the reception light signal to the target value.

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: An optical pickup device has first and second light sources that emit first and second laser beams of different wavelengths, an object lens that concentrates the first and second laser beams on a data recording surface of an optical disk, an optical separator disposed between the first and second light sources and the object lens, and an optical monitor that detects a quantity of light of the second laser beam. The optical separator has a wavelength selecting film that, on one hand, reflects the first laser beam emitted from the first light source toward the object lens and, on the other hand, transmits the second laser beam emitted from the second light source to the object lens, and a reflector that reflects a part of the second laser beam emitted from the second light source toward the optical monitor.

Abstract: An apparatus and method for automatic power control is disclosed. An optical recording apparatus utilizes a low-speed, peak-hold circuit to obtain and output a maximum of a front photodiode output signal during a predetermined window or plurality of windows of a total duration long enough to allow maximum peak-hold signal to stabilize. After stabilization, the maximum peak-hold signal is sampled and held in a sample and hold circuit. A reset then clears the signal and reinitializes the peak-hold circuit. In accordance with the difference between a reference voltage and the held peak-hold signal, a feedback controller unit outputs the required current level into a driving unit for producing desired recording pulses into a laser diode for recording information pits into an optical disc. A calibration gain may be used when, due to insufficient FPD response speed, the held signal is different than the real optical power output.

Abstract: A method for controlling a specific output power level emitted from a laser diode (LD) in an optical pick-up head unit (OPU) is disclosed. The LD is configured to provide a plurality of output power levels for accessing/recording an optical disc. The method includes: determining a specific power control value according to a first output power level, a second output power level, a first power control value of the first output power level, and the specific output power level, wherein the first output power level is less than the specific output power level and greater than the second output power level; and driving the LD to emit the specific output power level according to the specific power control value, the first power control value, and a second power control value of the second output power level.

Abstract: A method and an apparatus which controls write power of an optical driver by optimizing the number of channels used to drive a laser diode in a write mode while stabilizing the level of a write power voltage at an early stage of the write mode. The method of controlling the write power includes checking whether the write power provided to the laser diode included in the optical driver is stable, controlling the write power by increasing the number of channels used to control the write power so as to provide sufficient write power to drive the laser diode in response to the write power provided to the laser diode being unstable, and controlling the write power by using less channels than the channels used in response to the write power being unstable in response to the write power provided to the laser diode being stable. Accordingly, it is possible to reduce the size of a firmware by preventing channels unnecessary to perform a write mode from being used.

Abstract: There provided an optical disk recording/reproducing method and an apparatus thereof capable of constantly forming an optimum mark region while appropriately correcting recording conditions. A sample hold circuit 6 detects and holds the level of a TPP signal to output a state monitoring signal. A reference level setting portion 8 holds the level of the state monitoring signal at which an optimum recording state is obtained and outputs a reference level signal. A recording state determining portion 7 outputs a record shortage signal and a record surplus signal based on the result of comparison between the reference level signal and the state monitoring signal. An LD output correcting portion 9 outputs an LD output correcting signal based on the record shortage signal and the record surplus signal as well as a record data signal.

Abstract: An optical disc apparatus provided with an automatic power control circuit which controls power of laser light by obtaining a difference between a value detected by a front monitor 6 and a target value individually for reproduction power and for recording power includes: a detector 7 for detecting light reflected from an optical disc, a sample-hold circuit 26 which performs on an output of the detector 7 a sample-hold operation at the timing of the reproduction power; and a microcomputer 29 which computes a reference value from the reflected light of the reproduction power at the timing just before the start of a recording operation after receiving a recording command until opening of a recording gate, and at the time of recording operation an intensity of reflected light on which a sample-hold operation is performed is compared with the reference value to correct a target value of the reproduction power.

Abstract: Method and device for generating a stable power control signal in a CD recorder. The power control signal for controlling a laser diode may be a read level, an erase level and a write level. A pickup device outputs a feedback control signal to a read control circuit, and a read power control voltage is thus obtained. Then, the read power control voltage is inputted to a write control circuit, which generates first and second write power control voltages. The read level equals a reference voltage added by the read power control voltage, the erase level equals the read level added by the first write power control voltage, and the write level equals the erase level added by the second write power control voltage, so the read power control voltage and thus the read, erase and write levels are automatically and dynamically adjusted as the feedback control signal varies.

Abstract: A signal detection sections detect the light intensity modulated by the phase pits as ROM signals from the return lights of an optical storage medium that has phase pits and a recording layer to simultaneously regenerate data in the ROM and RAM, and detect the RAM signals where the return lights were modulated by the recording film. A feedback circuit reduces the cross-talk of the phase pits of the RAM signals of the recording film by feeding back the ROM signals to the laser drive current of the laser element, and a circuit for adjusting the feedback circuit so as to present a constant cross-talk suppression effect regardless the temperature change of the laser element. Since the feedback gain is changed by changing the laser temperature, an RF feedback gain, with which MO signals are not deteriorated by the change of the laser temperature, can be set.

Abstract: A laser power controller includes a loop control section to control a laser light output level of an optical head that applies laser light onto a disk for recording data to be a prescribed value, a DAC control section to hold as a previous level a laser control level preceding switching of a laser output level upon track change between a groove track and a land track during recording, and an analog SW to select the DAC control section to control the laser light output level by the previous level for a certain time period from the track change and to select the loop control section after the certain time period.

Abstract: When the recording capacity of an optical recording medium is increased, both reproduction characteristics and a tilt margin are improved. Specifically, when a laser beam is projected onto an information recording layer of the optical recording medium to reproduce information, a laser beam having a wavelength of 400 to 410 nm is employed. In addition, an objective lens which converges the laser beam and has a numerical aperture NA of 0.70 to 0.90 is employed. The reproduction is started by projecting the laser beam. A reproduction signal obtained by projecting the laser beam is decoded by means of a PRML detection method to generate reproduction data of the optical recording medium. When the quality of the reproduction data deteriorates, the power of the laser beam is temporarily increased.

Abstract: A light emitting unit is caused to emit a laser beam having a pulse width T1 broader than a pulse width T2 used at a time of recording, and a light receiving unit is caused to receive the laser beam and to output a first detection signal. A first control signal V1 is generated by comparing a value held at a peak level of the first detection signal with a target value of a quantity of the laser beam, and a second control signal V2 is generated by comparing the first control detection signal with the target value of a quantity of the laser beam.

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: A laser power control device for use in an optical recording and/or reproducing apparatus that records data on and/or reproduces data from an optical recording medium by driving a laser diode with a laser diode driver.

Abstract: An apparatus and a method of determining an optimal writing power for an aged writable disk after checking whether a writable disk is aged or not, are discussed. The apparatus and method according to an embodiment read signals written on a writable disk, judge whether or not the writable disk is aged based on a signal characteristic, e.g., a level difference between the read signals before and after an equalization and jitter of the read signals, and conduct an OPC for the writable disk to obtain a precise optimal writing power if the disk is judged to be aged. The precise optimal writing power can prevent deterioration of reproduction characteristic of recorded data even though an aged writable disk is used.

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 pickup apparatus is provided with two light sources; an objective lens for focusing light originating from each light source on an optical recording medium; a light separation optical element for transmitting or reflecting the light originating from each light source; a collimator lens for converting the light originating from each light source into a generally parallel beam; an upward-directing mirror for changing the optical path of the light originating from each light source by reflecting it; reflectors disposed between the light separation optical element and the respective light sources, for reflecting parts of light beams emitted from the light sources, respectively; photodetectors for detecting light beams reflected from the reflectors, respectively; and an APC circuit for controlling the power of the light beam emitted from each light source in accordance with a detection output of each photodetector.

Abstract: A reverse pattern is formed in a track adjacent to a specified track on an optical recording medium with a predetermined light beam capable of writing large recording marks. Thereafter, a normal pattern is formed in an area, of an adjacent track, which is adjacent to the reverse pattern in the specified track with recording light beams of various strengths, the adjacent track being adjacent to the specified track. The specified track is read to detect a plurality of read-out signals according to individual light beam conditions. The adjacent track is read to detect a plurality of read-out signals according to individual light beam conditions. An optimum recording condition is determined for the specified track from the plurality of light beam condition and the read-out signals from the specified track and the adjacent track, and information is recorded in the specified track according to the optimum recording condition.

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: A method for minimizing spherical aberration in an optical read/write drive caused by variances in lens thickness and laser wavelength. The method provides an economic solution that pairs objective lenses with laser diodes such that the spherical aberration caused by the objective lens is offset by the spherical aberration caused by the laser wavelength, thereby minimizing or completely canceling the overall spherical aberration.

Abstract: A recording condition compensation method for preventing a degradation of recording quality and stably achieving excellent recording quality is provided for an information recording apparatus. This method includes the steps of detecting temperature information in the vicinity of a light source at a predetermined timing, acquiring wavelength information of an optical beam emitted from the light source based on the detected temperature information and pre-acquired wavelength temperature characteristic information of the optical beam emitted from the light source, acquiring wavelength dependency information of a recording condition for an information recording medium, and compensating the recording condition for recording information on the information recording medium based on the wavelength information and the wavelength dependency information of the recording condition.

Abstract: The present invention relates to a method for controlling recording optical power. When a recording operation is paused, a playback signal characteristic for recorded data is detected. The recording optical power is controlled based upon the detected playback signal characteristic and hence the recording operation is resumed at the controlled recording optical power. Therefore, even though a characteristic of an optical pickup or disc varies when the recording operation is paused and resumed, an optimum recording operation can be performed and a playback characteristic for recorded data can be improved.

Abstract: A light source driving unit includes a modulating signal generating section generating modulating signals based on driving waveform generating information of a light source, a current source selecting section selecting one or more currents output from current sources based on the modulating signals, a light source driving section generating a current having multi-levels based on the one or more currents selected and supplying the generated current to the light source to drive the light source so that light in multi-levels is generated from the light source, and a cancelling section adding a signal error amount which cancels differences in amounts of signal delays generated between the modulating signal generating section and the light source driving section at a stage prior to the current source selecting section.

Abstract: In an optical disk apparatus, recording information by irradiating a laser light from a laser diode LD upon a recording surface thereof, while rotationally driving an optical disk by means of a spindle motor 207, being provided with a front monitor diode FMD for monitoring the laser light from the LD therein, a controller portion 205 detects deterioration of the laser diode, including the kink phenomenon, in particular, of loosing the linearity in the driving characteristic thereof caused due to driving under the condition of high temperature, by comparing a laser light output detected by the FMD to that, which is detected previously, within recording operation of the apparatus, and it also makes controls to lower the rotation velocity of the optical disk. This is suitable, in particular, to the optical disk apparatus of a super or ultra-thin type.

Abstract: In an optical disc drive, a laser light source emits a laser beam having an intensity changeable with the amount of drive current supplied. A first photodetector receives the laser beam reflected from an optical disc, thereby generating a readout signal. A second photodetector receives the laser beam, generates an electric signal representing the power of the laser beam received, and outputs the electric signal as a light quantity detection signal. A feedback control loop compares the level of the light quantity detection signal with a predetermined target value and regulates the drive current such that the level of the light quantity detection signal approaches the target value. In reading data from the optical disc, the target value is changed so as to compensate for a variation of the sensitivity of the second photodetector, thereby controlling the power of the laser beam emitted from the laser light source.