Abstract: An information recording method using a recording medium includes forming a plurality of recording pulses in accordance with both a reference waveform having been stored in the recording medium and data regarding a shifting value relying on material of the recording medium also having been stored in the recording medium in a table manner, and recording information included in the plurality of recording pulses to the recording medium. The recording information is arranged to be stored according to the material of the recording medium.

Abstract: An optical pickup device according to the present invention includes: a first light source that outputs a first laser beam; a second light source that outputs a second laser beam; and an optical system that irradiates an information medium with the first and second laser beams. The information medium includes: an information layer on which user data is written; and a recording layer on which visible information, which is directly visible to a user, is recorded. The optical pickup device is characterized by outputting the first laser beam in writing the user data on the information layer but outputting the second laser beam in recording the visible information on the recording layer.

Abstract: A photodetection device is provided with a photoelectric converter portion that converts light to electric current, an electrical current/voltage converter portion, including a feedback circuit that returns at least part of the output to the input side, that converts the electrical current received from the photoelectric converter portion to a voltage corresponding to the resistance value of the feedback circuit and outputs the voltage, where the feedback circuit includes a first MOS transistor that allows the resistance value to be varied in accordance with the gate voltage.

Abstract: A hybrid LDD includes a read channel to selectively output a read current, a plurality of write channels, each to selectively output a different write current, and an oscillator channel to selectively output an oscillator current. Additionally, the hybrid LDD includes programmable LDD controller that receives the plurality of enable signals from the external controller, and based on the enable signals, controls timing of the currents output by at least the write channels. The programmable LDD controller can also control timing of the currents output by the read and oscillator channels, based on the enable signals. Further and alternative embodiments are also provided.

Abstract: An optical recording medium is provided for 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 laser driving circuit employing a recording compensation circuit configured to generate a light emission timing of a laser on the basis of recorded data and a recording clock signal which are supplied to the recording compensation circuit includes: a phase synchronization circuit; a skew determination circuit; and a data latching circuit.

Abstract: An over current protection device is described. It includes a plurality of input channels for receiving an input signal; a plurality of low pass filters coupled to a first group of the plurality of input channels, wherein each low pass filter is associated with one input channel within the first group of input channels, the plurality of low pass filters operative for removing spikes in associated with the input signal; and a plurality of digital to analog converters coupled to a second group of the plurality of input channels, wherein each digital to analog converter is associated with one low pass filter in the second group of input channels, the digital to analog converters operative for triggering over current protection when a signal received from the associated low pass filter is beyond a preset level, wherein the over current protection device is on chip with the laser diode driver.

Abstract: A write control method which varies a write power in response to a recording speed, a recording density, and a type of recording medium, and an optical disc recording apparatus suitable for the write control method. The write control method includes preparing a plurality of standard power values corresponding to recording speeds or recording densities for a plurality of record marks, selecting one of the plurality of standard power values with respect to a record mark to be recorded according to a recording speed or a recording density, and controlling write power of a laser beam according to the selected standard power value. The write control method and apparatus improve recording performance of an optical disc recording apparatus by differently setting write power values according to recording speeds, recording densities, and types of recording media.

Abstract: A recording and reproducing method has a recording pulse generating step of generating a recording pulse to set timing of a beam emitted from a laser according to data to be recorded on an information recording medium; a laser power control step of controlling a laser drive current according to a recording laser power; a beam detecting step of detecting a power of the beam emitted from the laser; a signal detecting step of detecting a signal level of a reproduction signal read out from the information recording medium; a step of binarizing the reproduction signal to generate a binarized signal; a step of generating a data signal synchronized with a reference clock signal with use of the binarized signal; and a step of detecting a shift in time interval between the binarized signal and the reference clock signal and feeding the shift back to the recording pulse.

Abstract: A method of recording marks onto an optical disc, the optical disc comprising an information layer, by irradiating the information layer by a pulsed radiation beam, a mark (I3 . . . I14) having a time length of nT, n representing an integer larger than one and T representing the length of one period of a reference clock, being recorded by a sequence comprising m write pulses separated by cooling periods, the write pulses within the sequence being allowed to have different time lengths, the write pulses comprised in sequences corresponding to marks of different time lengths being allowed to have different lengths, m being an integer number given by Floor(n/?), where Floor(n/?) defines the largest integer smaller than n/?, wherein a is an integer number larger than or equal to 2. The method characterized by modifying at least the sequence comprising the longest write pulse such that the longest write pulse is replaced by two write pulses.

Abstract: A calculation of a reliability value |Pa?Pb|?Pstd, representing represents a maximum likelihood decoding result on a portion which corresponds to a start or termination edge of a recording mark and has a high probability of error occurrence by a maximum likelihood decoding method, is performed on each combination of a predetermined mark length and a space length immediately before the mark and each combination of the mark length and a space length immediately after the mark. Based on the calculation result, a recording parameter is optimized, and recording reflecting the optimized recording parameter is performed.

Abstract: A reading devices suppresses deterioration of the recording marks caused by increasing the output laser power to compensate for a drop in the S/N ratio when reading at a high speed information recorded to a high density recording medium. To read information recorded to an optical data recording medium that is written and read using a laser beam output from a semiconductor laser, the reading method modulates a high frequency current on the drive current of the semiconductor laser to output the laser beam, and changes the light modulation rate according to the selected linear velocity used for reading. The light modulation rate is the ratio Pp/Pave between the peak power Pp and the average read power Pave of the light intensity of the high frequency modulated laser beam.

Abstract: A modulation control system for use with a high frequency modulator is described. This system comprises a latch for selectively receiving enable signals, wherein the latch transmits a latched signal in response to receiving at least two of the enable signals; a selection device coupled to the latch for receiving the latched signal, a voltage source, and a terminal for receiving at least one of the enable signals, wherein the selection device transmits a selected signal; and a logic device coupled to the selection device and a terminal for receiving a modulated enable signal, wherein the logic device transmits a synchronized signal for either enabling or disabling the high frequency modulator in response to receiving the selected signal associated with at least one of the enable signals.

Abstract: An optical disc apparatus capable of obtaining an effect to reduce the laser noise without shortening the laser diode service life or increasing the power consumption. The optical disc apparatus includes a laser diode for emitting a laser beam, a laser driver for driving the laser diode, a detector for monitoring a first power emitted from the laser diode, a detector for monitoring a second power applied to an optical disc, and an attenuator for attenuating the first power. The light attenuation factor of the attenuator is changed by the ratio between the first power and the second power.

Abstract: According to one embodiment, an optical recording medium is provided in which interlayer crosstalk is low and in which stable and high-quality recording characteristics can be obtained. To this end, an optical recording medium comprises a first recording part which includes a first recording layer and a first light reflecting layer and which is disposed on a side closer to a light receiving surface, and a second recording part which includes a second recording layer and a second light reflecting layer and which is disposed on a side farther from the light receiving surface, the first recording part and the second recording part being stacked, wherein the thickness of the second light reflecting layer is larger than the thickness of the first light reflecting layer.

Abstract: A method for controlling read power and an open-loop read control device using the same. The open-loop read control device is used in an optical disk writer and includes a memory, a DAC and an amplifier. The optical disk writer includes a pickup head device having a laser diode. When writing is disabled, the read power of the optical disk writer for reading the disk corresponds to a specific voltage. The memory stores a relationship curve and outputs a corresponding reference value corresponding to the specific voltage. The DAC converts the corresponding reference value into an analog corresponding reference value. The amplifier receives the analog corresponding reference value and outputs a read power control voltage, which controls the laser diode to generate a substantially constant read power in the write process.

Abstract: There are provided: an optical recording method containing a focus point controlling step, and an interference image recording step; an optical recording apparatus containing a focus point controlling unit, and an interference image recording unit; an optical recording medium recorded in accordance with the optical recording method; and an optical reproducing method reproducing a recorded information recorded in accordance with the optical recording method.

Abstract: The invention relates to recording methods for recording information on a dual layer recordable disk, and to corresponding recording devices. In one such method and recording device the OPC-area is variably located on a layer of the disk. In a preferred embodiment the OPC-area is located relative close to the radius where the data stream switches from the first layer to the second layer. This reduced additional time required for jumping to a fixed OPC-area. Furthermore, in another such method and device the information to be recorded is equally divided over both layers of the dual layer disc. This avoids additional time required for finalization.

Abstract: An optical recording/reproducing system 1 reads, based on a predetermined reproduction clock, information associated with a recording track of a recording medium by irradiating frequency light. The frequency light is scanned at a predetermined scan velocity. The optical recording/reproducing system includes a computer 13, a DSP 49, and a LD driver that modulate light by a drive signal on which a frequency signal is superimposed to thereby output the frequency light, and synchronizes a frequency of the frequency signal with a frequency of the reproduction clock according to the scan velocity.

Abstract: An adaptive writing method of a high-density optical recording apparatus and a circuit thereof. The circuit includes a discriminator for discriminating a magnitude of a present mark of input NRZI data and magnitudes of leading and/or trailing spaces of the input NRZI data, a generator for controlling the waveform of a write pulse in accordance with the magnitude of the present mark of the input NRZI data and the magnitudes of the leading and/or trailing spaces of the input NRZI data to generate an adaptive write pulse, and a driver for driving a light source by converting the adaptive write pulse into a current signal in accordance with driving power levels for respective channels of the adaptive write pulse. The widths of the first and/or last pulses of the write pulse waveform are varied in accordance with the magnitude of the present mark of input NRZI data and the magnitude of the leading and/or trailing spaces, thereby minimizing jitter to enhance system reliability and performance.

Abstract: A data recording/reproducing system (1) reads a recording signal written on a recording track of a recording medium (3), by using light, which is modulated by a drive signal wherein a frequency signal is superposed for scanning the signal along the recording track at a prescribed scanning speed. Then, the system reproduces the read signal as data. The data recording/reproducing system is provided with a computer (13) for controlling the superposition frequency of the frequency signal for the drive signal corresponding to the scanning speed, and an LD driver (17).

Abstract: An optical disc drive according to the present invention includes an optical pickup and a writing control section for instructing the optical pickup to record a mark, representing the information to be written, on the optical disc. In recording the mark on the optical disc, the writing control section instructs the optical pickup to irradiate the same area on the optical disc with a light beam a plurality of times so that the mark is recorded in that repeatedly irradiated area.

Abstract: A laser drive circuit is utilized to record data with a good signal quality over a wide range of linear velocities to an optical information recording medium. Specifically, the laser drive circuit of an optical information recording apparatus sets a ratio of a recording power to a power at which a reproduction signal quality reaches a threshold value to be relatively low at low velocities, and relatively high at high velocities.

Abstract: An information recording apparatus (2) is for forming a record mark corresponding to a recording signal by applying a laser beam to a recording medium, and is provided with: a light source (21) for emitting the laser beam; and a signal generating device (22) for generating a recording pulse signal for driving the light source on the basis of the recording signal, the recording pulse signal includes a mark period and a space period, a level of the recording pulse signal corresponds to a recording power by which waveform distortion is greater than or equal to an upper limit (L) or is less than or equal to a lower limit (?L) of an amplitude limit value on a limit equalizer (15), in the mark period corresponding to a long mark.

Abstract: Disclosed herein is an optical recording apparatus which may record post pre-format recording information on an optical recording medium which has a guide portion formed in advance for guiding a light beam and a plurality of address portions for specifying individual positions of the guide portion, which may include position information detection means for detecting position information of a recording region in which significant information is recorded along the guide portion and a breakdown region which is part of the guide portion or/and the address portions and is broken down so as not to be detected using the light beam, servo means for controlling the position of the light beam based on the position information, and laser light intensity adjustment means for adjusting the intensity of the light beam in order to record information based on a predetermined format in the recording region and thermally break down the breakdown region.

Abstract: A hologram recording and reproducing device controls an optical beam output from an external cavity semiconductor laser to improve a diffraction efficiency. The hologram recording and reproducing device includes an external cavity laser, a photodiode, a laser drive circuit and a laser diode controller. The external cavity laser has a laser diode adapted to emit an optical beam that is used to generate data light and reference light with which a hologram recording medium is irradiated. The photodiode detects the amount of the optical beam output from the external cavity laser. The laser drive circuit supplies a current to the external cavity laser. The laser diode controller controls the laser drive circuit to ensure that a value obtained by integrating the detected intensity of the optical beam with respect to time over a predetermined period is equal to predetermined recording energy.

Abstract: A method and apparatus for accomplishing an OPC (optimal power calibration) at a test area secured in data recording area of a writable optical recording medium and detecting an optimal writing power appropriate to the test area. The method searches for a marginal area adjacent to a data section recorded on an optical recording medium, records test data on the marginal area discovered in the searching step while changing a writing power; and reproduces the test data recorded on the marginal area and determining an optimal writing power based upon the characteristics of the reproduction signal. The method and system can reduce delay time required to move an optical pickup inward and outward to accomplish the OPC operation and enhances writing characteristics since an optimal writing power is obtained from a test area which is very close to data area to record input data.

Abstract: An optical head that is restrained from becoming larger, even if it is used for an optical-information recording medium that includes a plurality of information recording layers. In this optical head, a collimating lens is formed by a concave lens disposed on the side of a light source and a convex lens disposed on the side of an objective lens. A collimating-lens actuator moves the convex lens in a direction where a spherical aberration is cancelled which is generated according to the thickness of a light transmission layer up to an information recording layer of the optical-information recording medium. An aperture stop is provided on the side of the collimating lens with respect to the objective lens, and the aperture stop is located near the focal position of the convex lens on the side of the objective lens.

Abstract: An operating current modifying device is provided for a power generating element. The power generating element generates an output power when the operating current is larger than a threshold current in the power generating element. A functional relationship is between the threshold current and the temperature of the electrical device. The operating current modifying device includes a threshold current modifying module, a power modifying module, a current compensating module, and a power control module. The threshold current modifying module receives a temperature signal from the power generating element to output a threshold current modifying signal according to the temperature signal and the functional relationship. The power modifying module receives a power feedback signal from the power generating element and a target power signal to output an operating current modifying signal.

Abstract: An optical pick-up device includes a laser source enabling emission of at least two light beams with different wavelengths, an objective lens which focuses the light beams emitted from the laser source on an optical disc, an optical detector which receives a light reflected from the optical disc, a front monitor which receives a part of the light beams emitted from the laser source, a front monitor light-guiding plate which guides part of the light beams emitted from the laser source to the front monitor. The front monitor light-guiding plate is arranged between the laser source and the objective lens, at least a part of a region of the front monitor light-guiding plate illuminated by the light beams emitted from the laser source has a predetermined shape which causes the light beams to change traveling direction thereof by refraction and then be guided to the front monitor.

Abstract: An apparatus for effecting at least one of recording and reproducing information. A first light source has a light intensity and emits a light beam having an emission wavelength. A second light source has another light intensity and emits a light beam having an emission wavelength different from that of the first light source. An optical system guides a light beam emitted from the first light source to a recording medium and guides a light beam reflected from the recording medium to a first photodetector, which generates an output. Another optical system guides a light beam emitted from the second light source to the recording medium and guides another light beam reflected from the recording medium to the second photodetector. A separating optical element guides the light beam emitted from the first light source to the second photodetector, which generates an output.

Abstract: A method and apparatus for manufacturing an optical disk master and an optical disk, including measuring the reflectance of laser light at each of a plurality of radius positions by applying the laser light to an optical disk master-forming substrate provided with an inorganic resist layer, the laser light having a non-recording laser power smaller than a recording sensitivity of the inorganic resist layer, producing recording power control data indicating recording laser powers in accordance with the radius positions of the optical disk master-forming substrate by using the reflectances measured, forming an exposure pattern on the inorganic resist layer by applying the laser light to the optical disk master-forming substrate on the basis of the recording power control data while the recording power is varied in accordance with the radius positions, and developing the inorganic resist layer provided with the exposure pattern so as to prepare an uneven pattern.

Abstract: In a super-resolution optical disk for the purpose of achieving an increase in the density of recording data by reproducing a recording mark smaller than optical resolution, the optimum reproduction power needs to be determined since the quality of a super-resolution reproduced signal strongly depends on the reproduction laser power. However, since the track error signal required for tracking servo also depends on the reproduction power, there is a need for a method for determining the reproduction power taking into account both the stabilization of tracking servo and a quality improvement of the reproduction signal. The reproduction power is changed under conditions with focusing servo applied but without application of tracking servo. Thereby, a cross track signal is detected to identify a reproduction power region that leads to quality improvement of both a reproduction signal and a track error signal.

Abstract: According to one embodiment, single-sided dual-layer recordable disc 100 may be used. Information recording is performed by forming mark and space portions on data area DA using modulated laser power. Pp denotes the maximum laser power or peak power for forming the mark portion, and Pb denotes the bias power for forming the space portion. Power ratio Pb/Pp is calculated for each of recording layers L0 and L1. Information is recorded on any of the recording layers L0 and L1 based on the result of calculation. Here, the calculated power ratio Pb/Pp changes among the recording layers L0 and L1, thereby optimizing the recording condition for a multi-layer recordable optical disc within relatively short time.

Abstract: Provided is an optical disk apparatus which optimizes a frequency of a high frequency superimposing operation upon reproduction so that good reproduction performance is realized in a wide irradiation power range of a laser power. The optical disk apparatus includes: a semiconductor laser device; an optical disk discrimination circuit for performing laser discrimination; a driver device including a drive circuit for supplying direct drive current to the semiconductor laser device and a high frequency superimposing circuit for superimposing high frequency current on the drive current; and a high frequency superimposing variable circuit for changing a frequency of the high frequency current in which when information is reproduced, the high frequency superimposing variable circuit sets the frequency of the high frequency current for reproducing a multi-layer disk to be higher than the frequency of the high frequency current for reproducing a single-layer disk.

Abstract: A recording method, a recording apparatus, and an optical recording medium that can improve quality of a signal reproduced from a high multi-speed recording medium. The recording method includes generating a box type recording pattern including a first pulse, which has a duration determined according to a length of a recording mark and which has a first power level, and a second pulse which has a second power level different from that of the first power level, and recording data according to the box type recording pattern.

Abstract: A writing current circuit (42) supplies a controlled electrical current to a laser diode (34) for recording data swiftly onto a DVD (16). A plurality of current sources (62) in the writing current circuit (42) supply electrical current to the laser diode (34). Each current source (62) respectively receives a single output signal from a current control register (52) included in the writing current circuit (42) which activates or deactivates the current source (62) for supplying a particular quantity of electrical current to the laser diode (34). In each current source (62), electrical current flows to the laser diode (34) through a MOSFET output transistor (142) connected in series with the laser diode (34). Each current source's MOSFET output transistor (142) has a gate insulating layer which is thinner than the gate insulating layer conventionally used for a MOSFET output transistor (142) that is energized by the electrical potential the it applied to the writing current circuit (42).

Abstract: An adaptive writing method of a high-density optical recording apparatus and a circuit thereof. The circuit includes a discriminator for discriminating a magnitude of a present mark of input NRZI data and magnitudes of leading and/or trailing spaces of the input NRZI data, a generator for controlling the waveform of a write pulse in accordance with the magnitude of the present mark of the input NRZI data and the magnitudes of the leading and/or trailing spaces of the input NRZI data to generate an adaptive write pulse, and a driver for driving a light source by converting the adaptive write pulse into a current signal in accordance with driving power levels for respective channels of the adaptive write pulse. The widths of the first and/or last pulses of the write pulse waveform are varied in accordance with the magnitude of the present mark of input NRZI data and the magnitude of the leading and/or trailing spaces, thereby minimizing jitter to enhance system reliability and performance.

Abstract: According to one embodiment, an optical disk device includes a laser light source that emits laser light to be applied to an optical disk, an automatic power control circuit that controls a laser output of the laser light source, and a control processor that performs a setting data transmission process for the automatic power control circuit. The automatic power control circuit includes an operation setting module that makes an operation setting according to setting data obtained in the setting data transmission process of the control processor and a condition determining module that determines whether an operation setting permission condition containing the number of clocks during a transmission period of the setting data is adequate, and inhibits the operation setting of the operation setting module when the operation setting permission condition is not adequate.

Abstract: Recording information is disclosed in which an information recording medium is irradiated with a recording energy beam that is power-modulated into at least a record power level and a record-ready power level lower than the record power level. The information is recorded on the recording medium in the form of length and interval of a mark portion. When forming a mark portion of a predetermined length, the radiation energy of the energy beam is increased as compared with when forming a mark portion of a different length before or after the first pulse of an energy beam pulse train including at least a pulse for forming the mark portion.

Abstract: A recording/reproduction apparatus, comprising a first recording section for recording test information onto a medium using at least one recording power, a reproduction section for reproducing at least one test signal indicating the test information from the medium, and a second recording section for recording information onto the medium using one of the at least one recording power. The reproduction section comprises a decoding section for performing maximum likelihood decoding of the at least one test signal and generating at least one binary signal indicating a result of the maximum likelihood decoding, a calculation section for calculating a reliability of the result of the maximum likelihood decoding based on the at least one test signal and the at least one binary signal, and an adjustment section for adjusting a recording power for recording the information onto the medium to the one recording power based on the reliability.

Abstract: Recording information is disclosed in which an information recording medium is irradiated with a recording energy beam that is power-modulated into at least a record power level and a record-ready power level lower than the record power level. The information is recorded on the recording medium in the form of length and interval of a mark portion. When forming a mark portion of a predetermined length, the radiation energy of the energy beam is increased as compared with when forming a mark portion of a different length before or after the first pulse of an energy beam pulse train including at least a pulse for forming the mark portion.

Abstract: Recording information is disclosed in which an information recording medium is irradiated with a recording energy beam that is power-modulated into at least a record power level and a record-ready power level lower than the record power level. The information is recorded on the recording medium in the form of length and interval of a mark portion. When forming a mark portion of a predetermined length, the radiation energy of the energy beam is increased as compared with when forming a mark portion of a different length before or after the first pulse of an energy beam pulse train including at least a pulse for forming the mark portion.

Abstract: An optical disc recorder that records information on an optical disc by means of a laser diode that forms pits in the optical disc through the application of a write pulse of a previously set type, the recorder having a reference power setter that sets a reference power that is the reference value of a drive power of the write pulse, a pulse type checker that checks whether the type of write pulse set consists of a plurality of pulses, which allows the drive power to be set for each pulse of a plurality of pulses, a power corrector for correcting the drive power of at least one pulse of the write pulse by adding a previously set correction power to the reference power, and a drive controller that applies the write pulse, which consists of the pulse with the reference power and the at least one pulse with the drive power corrected.

Abstract: When recording is carried out in a DVD-RAM, if at least one address mark could have been detected at the header section, after a test light emission for a laser power control is carried out at a GAP section, normal recording is carried out from GUARD1. Herein, if the delay time in the reproduced data would have increased, and if the head of the GAP section has been passed by at the timing when the AM4 is detected in a period during judging whether the fourth AM has been detected or not, it would not be possible to carry out a test light emission normally at the GAP section. In an optical disc recording device of the present invention, when any of the first to third address marks could have been detected, a test light emission is carried out at the GAP section as conventional, and normal recording is carried out from GUARD1 with controlling the laser powers on the basis of that result.

Abstract: A driver includes a parameter generation module configured to generate timing parameters based upon a received bit stream. A timing encoding module is configured to determine a plurality of pulse defining parameters based on the timing parameters. A pulse generation module is configured to determine a plurality of generic pulses based on the plurality of pulse defining parameters. The pulse generation module is configured to combine the plurality of generic pulses into a plurality of enable signals. The pulse generation module is configured to selectively invert a first enable signal of the plurality of enable signals. The pulse generation module is configured to output the plurality of enable signals including the first enable signal to a laser driver.

Abstract: In the present invention, in order to permit recording operation of data by optimum recording power even at any recording position of inner circumference and outer circumference of an optical disc (1), PCAs (Power Calibration Areas) serving as a trial write area for adjusting recording power of laser beams are respectively provided at the inner circumferential side and the outer circumferential side of the optical disc (1) in the state where program area is put therebetween. In recording data into the program area of the optical disc (1), one PCA near from the recording position of data is selected to perform trial write operation to set write power of laser beams on the basis of trial write data to thereby permit recording operation of data at optimum laser power.

Abstract: The object of this invention is to provide an optical disc apparatus and an optical disc reproducing method that can realize an excellent reproducing operation by suppressing noise in the optical disc apparatus using an optical attenuator. In order to solve this object, a control voltage of the optical attenuator is changed according to reproduction power when reproducing the optical disc and an ambient temperature of the optical attenuator. In addition, the amplitude of a high frequency current for driving a laser diode is changed according to an attenuation factor of the optical attenuator.

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: 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, . . .