Abstract: An optical information recording medium reproducing device (1) reproduces information from a super-resolution optical information recording medium (100a) having the information stored therein by positioning, according to a random pattern system, a plurality of recording marks including a recording mark shorter than a resolution limit of an optical system. This reproducing device (1) performs test readings for measuring indexes each relating to a reproduction quality of the super-resolution optical information recording medium (100a) by emitting laser light onto a storage surface of the super-resolution optical information recording medium (100a), while changing a reproduction laser power from a predetermined initial value, and based on the indexes measured, sets a reproduction laser power for reproducing the information.

Abstract: An optical disk apparatus and control method having a rotation driver configured to rotationally drive an optical disk, a laser diode configured to emit a laser light to be irradiated upon a recording surface of the optical disk, for recording or reproducing information onto the optical disk, and a monitor device configured to monitor the laser light emitted from the laser diode. An intensity of the laser light emitted from the laser diode which is detected by the monitor device is memorized by a memory, a detector detects an abnormal condition of the laser diode, by comparing a present laser light intensity with a previous laser light intensity, and a controller controls a rotating velocity of the optical disk in dependence upon detection of the abnormal condition.

Abstract: An apparatus for writing data to an optical storage media and a servo control unit and a laser diode driver unit thereof. The apparatus making a laser diode emit light includes a servo control unit and a laser diode driver unit. The servo control unit includes a control unit for controlling a burning procedure and a modulation unit for outputting an encoded signal. The laser diode driver unit receives the encoded signal and includes a PLL unit, a write strategy generation unit and a lock/unlock detection unit. The PLL unit outputs at least one of a second clock signal and a second data signal according to the encoded signal. The write strategy generation unit outputs a control signal to control the laser diode according to the second clock signal and the second data signal. The lock/unlock detection unit outputs a lock indicator or an unlock indicator to the control unit.

Abstract: A power control apparatus and method for an optical drive is disclosed. The power control apparatus estimates the temperature rising effect of a laser diode and performs a partial open-loop power control, achieving accurate write power control. Therefore, regarding to a high-speed, high-density optical disk recording medium combined with multi-pulse write waveforms, the invention can also achieve accurate write power control even though the response speed of a front photodiode is much slower than the modulation speed of recording pulses of the laser diode.

Abstract: In a writing device for writing data at 1-time or higher recording rates, a first delay circuit capable of variably controlling a delay time in units of a relatively long time and a second delay circuit capable of variably controlling a delay time in units of a relatively short time are employed in a combined manner. A laser drive pulse can be controlled in the direction of the time base with high accuracy corresponding to any recording rates ranging from 1-time to higher, e.g., 8- or 12-time, speeds without using very large number stages of delay gates.

Abstract: A method and apparatus for controlling a light source for use with an optical disc having optimum power values for different stages in a writing signal for the optical disc, includes comparing current operational characteristics of the light source to previous operational characteristics, and, when the current operational characteristics differ from the previous operational characteristics and a stage in the writing signal has overlapping power, determining a compensation voltage based on the current operational characteristics and an optimum power value for that stage.

Abstract: An optical disk writing apparatus maintaining appropriate write power in real time with a simple configuration includes a buffer for recording data, a binarization circuit supplying data to the buffer, an LD writing data recorded in the buffer onto a DVD disk, a detector reading out from the DVD disk a signal representing data written by the LD at an arbitrary time during a period starting from when the amount of data recorded in the buffer and not yet written onto the DVD disk becomes zero until the amount of data reaches a predetermined number of ECC blocks, and a servo processor correcting an error in the data read out by the detector for every data amount susceptible to error correction at one time, evaluating the writing of the LD using the corrected signal, and controlling the energy density to be employed in writing data onto the DVD disk by the LD according to its own evaluation.

Abstract: A laser power control circuit includes a system control module for generating two write channel target values in a calibration mode, a driving module for driving a laser generator, and a detection module for detecting two laser power values of the laser generator. A write channel control module of the driving module generates two write channel signals according to the two write channel target values, respectively. The two laser power values respectively correspond to the two write channel signals. The system control module determines a first mapping relationship between a write channel target value and a laser power value according to the write channel target values and the laser power values. The system control module further determines a predetermined write channel target value corresponding to a predetermined laser power value according to the first mapping relationship in a run mode.

Abstract: A recording apparatus for recording record data onto a recording medium on which a plurality of recording layers are formed in a thickness direction, is provided with: a recording device for recording the record data into each of the plurality of recording layers by emitting each of a plurality of recording light beams to be focused on a corresponding one of the plurality of recording layers; a calculating device for calculating a leaked beam feature of another recording light beam, which is emitted to be focused on another recording layer other than one recording layer of the plurality of recording layers, leaking to the one recording layer; and an adjusting device for adjusting an emission condition of at least one of the plurality of recording light beams, on the basis of the calculated leaked beam feature.

Abstract: It is an object of the present invention to provide a recording condition closer to an optimum even for a medium unknown to a drive, and more particularly to provide a method especially effective when applied to code identification methods, such as PRML, wherein codes are identified based on amplitude information of an RF signal. In order to accomplish the object, an RF signal received from a photo-receiving part 108 of a pickup is converted into sampling data by an A/D converter 300, and a Viterbi decoder 302 performs code determination using the sampling data. Codes included in a reproduction signal are then determined by synchronizing recording pulses with the reproduction signal using the result of the code determination. Then, the result is used to specify a part to be detected in the codes, and finally an amplitude of the specified part is detected.

Abstract: An optical information recording reproduction device is disclosed, in which aberration detection is stably performed, so that an excellent record grade can be achieved. An RF signal is subjected to differential operation along a time axis of the signal, the RF signal being obtained from reflected light including primary light situated in the periphery of a primary dark ring enclosing zero-order light in a central portion of a beam spot formed on a pit; pulse signal waveforms are represented in an absolute value form, the pulse signal waveforms being generated in correspondence with front and rear ends of the beam spot on the time axis; the pulse signal waveforms represented in the absolute value form are stored into a storage medium; the stored, two pulse signal waveforms are combined to generate a beam profile of the beam spot formed on an optical recording medium; and a beam spot diameter, spherical aberration, and coma aberration of a record laser beam are adjusted based on the beam profile.

Abstract: The invention relates to an optical recording apparatus on optical carrier or disk, the apparatus has means for sampling a power level of an irradiation beam, e.g. a laser beam, that is capable of recording data in a data region (101) in response to an predefined input signal (NRZ). The irradiation beam (5) has a substantially constant power level in a first period (MT1), where the first period (MT1) is longer than the period of time associated with the maximum code run length (MRL) of the encoding scheme. Forward photo sensing means (FS 41, 40) is adapted to sample the power level in at least a sub-period of time (ST1) of the first period (MT1). The invention relaxes the requirements of the forwarding photo sensing means (FS), as the first period (MT1) may be extended beyond the time that was previously available for monitoring the power level of the irradiation beam.

Abstract: Laser power control arrangements interrupt power to a laser used in electro-optical readers upon detection of operating conditions not conforming to preestablished standards, and adjust power to the laser to enhance reader performance without violating prevalent safety standards. Dual monitors are used to independently monitor the output power of the laser.

Abstract: The present invention provides a flexible power interface control system and a method of the same capable of flexibly changing the LDD setting for complying with different controlling states or different write strategies. The different controlling states or write strategies may be used for different disk types or different writing modes. The flexible LDD setting in accordance with the present invention is contributing to improve the recording performance and stability of an optical disk drive for complying with various disk types or different writing modes.

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 method of recording information according to the present invention is adapted for recording information to an optical recording medium by forming on the optical recording medium a plurality of recording marks selected from a group consisting of several types of recording marks each with different lengths, wherein a bottom power of a laser beam used for forming at least one recording mark contained in the group is set to be higher than a reproducing power of a laser beam used for reproducing information. According to the present invention, since the bottom power helps to erase a recording mark, it is possible to maintain a high erase efficiency even when information is recorded by setting a high data transfer rate.

Abstract: An optical pickup apparatus, comprising: a light source to emit a light flux; a light converging system including an objective lens to converge the light flux emitted from said light source onto an optical information recording medium; a first diffraction element placed within an optical path up to the optical information recording medium; a light flux splitting element that is placed within the optical path from said light source up to the optical information recording medium and that splits an incident light flux emitted by the light source; a monitor element that receives a light flux split by said light flux splitting element and outputs a signal according to a received light amount; a second diffraction element placed between said light flux splitting element and said monitor element; and a control section that controls the drive of said light source according to the signal from said monitor element.

Abstract: A signal gain control method and system for use in optical disc drives to prevent undesirable saturation occurrences in circuit operations. The method includes fetching a preset reading front monitor diode signal and a preset gain controlling signal for reading; generating a front monitor diode signal by a front monitor diode signal conversion circuit; calculating a gain controlling signal based on the preset gain controlling signal for reading, the preset reading front monitor diode signal, and the front monitor diode signal by a signal processor; adjusting a gain for detection signals according to the gain controlling signal by a gain adjustment unit; and generating control signals according to the adjusted detection signals by a pre-amp module.

Abstract: A power controlling method for eliminating output power offset of a pick-up head in an optical disc drive. The power control method includes measuring a first predetermined power related to a first predetermined control signal in a predetermined procedure, inputting a test data containing a plurality of first bits and a plurality of second bits, activating a sample/hold circuit to form a close loop so that the first predetermined control signal can be received and utilized for driving a pick-up head to output a first power when the plurality of first bits are received, and calculating an offset power based on the first predetermined power and the first power for rectifying output power of the pick-up head.

Abstract: An optical information read/write apparatus according to the present invention includes: a light source 1 that emits a laser beam to access an information storage medium optically; a laser driver 51a for supplying drive current to a semiconductor laser as the light source 1; an RE superimposed current generator 51c for adding RE superimposed current to the drive current; a temperature sensor 35 for detecting a temperature around the light source 1; and a control section for switching the values of the RE superimposed current according to the temperature detected.

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, an optical recording apparatus, a one-chip CPU device, and a computer program. Reference data corresponding to a recording condition of a first recording layer, a physical characteristic value correlated with the recording condition, and a physical characteristic value correlated with a recording condition of a second recording layer are extracted from a data table in a memory, and the recording condition of the extracted reference data is set as a recording condition of a recording medium as an information recording target. When no correlated reference data exists, the closest reference data are extracted from the data table, and a recording pulse condition suitable for recording information on the second recording layer of an optical disk as the information recording target is extracted on the basis of the correlation between the recording condition of the reference data and the physical characteristic value.

Abstract: An optical information recording and reproducing apparatus comprises an optical disk having a reflection layer, an optical information recording layer, a super resolution layer and a protection layer on the recording surface of a substrate, a laser emission control unit for emitting the laser light to record and reproduce the optical information and changing the pulse-like emission pattern, a pickup for radiating by focusing the laser light and receiving the reflected light, a spindle and a spindle motor for supporting and rotationally driving the optical disk, and a reproduction signal processing unit for arithmetically processing the received signal.

Abstract: In an optical disc apparatus, whether an unrecorded recording layer without information recorded thereon is included in the multiple recording layers of the optical disc mounted inside the apparatus is judged. then when the unrecorded recording layer is judged to be present, a signal for focus offset adjustment is recorded in a non-user data recording area of the unrecorded recording layer, and reproduction of the recorded focus offset adjusting signal is followed by its quality evaluation, which is further followed by calculation and setup of an appropriate focus offset value based on evaluation results.

Abstract: An optical disk apparatus including: a light source; an objective lens for converging light emitted from the light source toward an optical disk; a first photodetection device for detecting reflected light from the optical disk and outputting a first signal; a signal processing section for receiving the first signal and generating a signal containing information recorded on the optical disk; a second photodetection device for detecting a portion of the light emitted from the light source and outputting a second signal; a light source driving section for receiving the second signal, and based on the second signal, driving the light source so that output power of the light source equals a target value; and an amplitude fluctuation detection section for detecting an amplitude fluctuation amount of the second signal, and if the amplitude fluctuation amount exceeds a predetermined value, changing driving characteristics of the light source driving section.

Abstract: An optical disc drive apparatus includes: a laser beam source; a collector device disposed as facing a disc that can record a signal, which collects a laser beam emitted from the laser beam source onto the disc; a record processing module which records the signal on the disc through the collector device while modulating laser power of the laser beam source; a reflecting light level detecting module which receives the reflecting light when the signal is recorded and detects a level of the reflecting light; a laser power control module which controls the laser power when the signal is recorded based on the detected level of the reflecting light; a tilt control module which controls a tilt angle between the disc and the collector device based on the detected level of the reflecting light; and a switching module which switches between control of the laser power and the tilt angle.

Abstract: A recording condition setting method includes the steps of: a) obtaining identification information from an information recording medium; b) searching through a table including history information indicative of temperature information detected in the vicinity of a light source and corresponding optimum recording power; c) extracting history information corresponding to the identification information; d) detecting temperature information detected in the vicinity of the light source; e) acquiring an optimum recording power by referring to the temperature information detected in step d) and the history information extracted in step c); and f) setting the optimum recording power acquired in step e) as a recording condition.

Abstract: Embodiments of methods and apparatus for compensating writing power in an optical disc device can compensate selected (e.g., OPC) writing power. When a writing operation is temporarily suspended (e.g., buffer under-run) during the writing operation, writing power is compensated in real time on the basis of the ? value detected from read RF signals for most recently recorded data and comparisons to selected writing power (e.g., optimum ? value stored therein through OPC).

Abstract: A front photo detector (FPD) of an optical pick-up for an optical recording and playing apparatus having no gain selection switch, a simplified configuration, an improved prevention of an abnormal operation due to an error in gain selection, and improved reliability. The front photo detector includes a photo diode unit, a current-voltage amplifying circuit, and a voltage amplifying unit. The photo diode unit outputs current proportional to the power of the light emitted from one of a plurality of laser diodes. The current-voltage amplifying circuit converts the current output from the photo diode unit into a voltage. The voltage amplifying circuit amplifies the voltage output from the current-voltage amplifying circuit by a predetermined gain.

Abstract: An information recording apparatus for recording information onto an information recording medium having a plurality of recording layers, by irradiating the information recording medium with laser light for recording, the information recording apparatus including: a setting device for setting a preferable irradiation condition of the laser light which is preferable to one recording layer in which the information is scheduled to be recorded, out of the plurality of recording layers, for each recording state of another recording layer out of the plurality of recording layers; and an irradiating device for irradiating the one recording layer with the laser light in the set preferable irradiation condition.

Abstract: When performing writing and/or reading of information to/from an optical disk provided with a wobble including time axis information, an occurrence of a reading error of the time axis information from the wobble is suppressed so that disabled reading of information from the optical disk and an occurrence of a writing error can be prevented. Evaluated parameters such as a CRC error rate of an ATIP signal, an FMDT jitter amount and a phase error between an ATIP synchronization signal and a frame synchronization signal of writing data are evaluated based on a range of set values. When the evaluated parameter is deviated from the range of set values, writing and reading speeds are changed, thereby increasing the reading accuracy of the wobble signal.

Abstract: The invention relates to a method for monitoring an optical disk drive performance quality by determining a laser diode quality indicator for a laser diode arranged in an optical disk drive for scanning an optical disk. The determining includes measuring (1000) an actual value (ITHACT) of a parameter (ITH) associated with a laser diode characteristic, obtaining (2000) a reference value (ITHR) of the parameter, comparing (3000) the actual value with the reference value for obtaining a comparison result (ICOM), and determining (4000) the laser diode quality indicator (Qual) from the comparison result. The laser diode quality indicator can at least take a warning level signaling a precursor for a defective state of the optical disk drive and an error level signaling a defective state of the optical disk drive. The laser diode characteristic can e.g. be a light-current relationship or a voltage-current relationship. The parameter can be associated with e.g.

Abstract: A calibration method for improving stability of write control signal during writing can be applied in a CD recorder. The CD recorder has a pickup device having a laser diode, and a write control device for outputting a write control signal. A first relationship curve showing the relationship between the write control signal and a light-emitting power generated by the laser diode is obtained by switching the pickup device into a de-focus state and switching the write control device into a close-loop mode. A second relationship curve showing the relationship between a gain of the write control device and the write control signal is obtained by switching the write control device into a long-term open mode. When a specific light-emitting power is adapted to write, a specific write control signal and a specific gain corresponding to the specific light-emitting power is obtained according to the first and second relationship curves.

Abstract: An optical pickup device using a laser beam comprising: a light-emitting element; a collimating lens; an objective lens; and a light-receiving element, wherein the laser beam emitted from the light-emitting element is converged on a recording surface of an optical disc to be disposed through a path related to the collimating lens and the objective lens, and the converged laser beam is entered to the light-receiving element reversely passing through the path after being reflected on the recording surface of the optical disc, the optical pickup device comprising: a front monitor light-receiving element for receiving a part of the laser beam emitted from the light-emitting element and detecting the amount of the laser beam; and an optical guiding member for guiding a part of the laser beam to the front monitor light-receiving element.

Abstract: A method is disclosed for adjusting write power when recording an optical disc. First, pre-setting a range of a write quality parameter and a write power. Next, moving a spindle motor and an optical pickup head to a target track. After the spindle motor is stable at the intended rotation speed as well as the optical pickup head is positioned correctly at the target track, then reading a write quality parameter. Then, determining whether the write quality parameter is in the range. When the write quality parameter is in the range, then according to the write power to write data to the target track. When the write quality parameter is out of the range, then adjusting the write power to write data to the target track.

Abstract: The optical head device includes a semiconductor laser for emitting a laser beam having an elliptical beam shape; a collimator lens for collimating the laser beam emitted from the semiconductor laser; a reflector including pair of belt-like pieces one of the surfaces of which is used as a reflecting face formed in a curved face having a curvature along their longitudinal direction, the pair of belt-like pieces being formed to be arranged in a major axis direction of an elliptical beam flux to sandwich the optical axis of the laser beam, and an optical sensor equipped with a condenser lens for detecting the strength of the beam reflected from the pair of belt-like pieces of the reflector.

Abstract: An optical disk drive includes an optical disk drive controller that can test the write channels between the controller and the laser diode driver. Using the results of this testing, the optical disk drive controller adjusts the characteristics of the write channel signals provided to the laser diode driver to correct for one or more detected imperfections in the write channel signals. Both the optical disk drive controller and the laser diode driver have communications ports to facilitate communication. The optical disk drive controller programs the operating characteristics of the laser diode driver so that the laser diode driver can be optimized for the measured characteristics of the write channels.

Abstract: Laser light irradiation can be performed on a recordable surface in a defocused state with a high-power laser beam with safety without incurring data destruction due to erroneous data recording or overwrite recording even in the recording on an eccentric disk or regardless of occurrence of wobbling of the disk surface. Laser irradiation is performed after moving an objective lens radially inwardly beyond a PCA located at an inner peripheral portion of the disk (or radially outwardly beyond the PCA located at an outer peripheral portion of the disk) by using a tracking coil.

Abstract: A recording medium and method for controlling a recording operation using at least two OPC information obtained from performing at least two OPC operations for the same drive. The method includes comparing the two PC information with each other, and controlling a recording operation of the recording medium based on the comparison result.

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 thermometer code registers (52) respectively store numerical values. A current control register (58) receives a numerical value from one of the thermometer code registers (52). Serial data specifies a sequence in which individual thermometer code registers (52) supply values to the current control register (58) thereby causing the writing current circuit (42) to supply a particular electrical current waveform to the laser diode (34). A plurality of current sources (62) respectively receive a single output signal from the current control register (52) which activates or deactivates individual current sources (62) for supplying a particular quantity of current to the laser diode (34).

Abstract: In an optical disk apparatus, transmittance and reflectance of a polarization beam splitter 13 to the S polarization and the P polarization of laser beams are adjusted so that a first polarization component level ratio in the laser beam received by a light receiver for reproducing signal 17 from a laser diode 11 via the polarization beam splitter 13, and a second polarization component level ratio in the laser beam received by a light receiver for monitoring light source 18 from the laser diode 11 via the polarization beam splitter 13 become equal or the difference between the first and the second polarization component level ratios becomes within a predetermined permissible range.

Abstract: A light detector includes a light-receiving device that receives a light beam applied from a light source irradiating an optical recording medium with the light beam and that generates detection signals, and a power monitor circuit section that generates a power monitor signal for monitoring output power of the light source in accordance with the detection signals. The device includes split light-receiving elements. The detection signals are output from the split light-receiving elements as split detection signals. The section includes an amplifying circuit generating the power monitor signal and outputting the power monitor signal as differential signals, a fixed resistor determining a gain of the amplifying circuit, and a position-detecting signal output circuit generating position-detecting signals in accordance with the split detection signals. At least the light-receiving device, the amplifying circuit, and the fixed resistor are integrated on an identical semiconductor substrate.

Abstract: A pickup of an optical reproducing/recording apparatus having a laser diode generating an optical signal with a current power value, and a laser diode power control device automatically controlling an output of the laser diode. The laser diode power control device has a sampler sampling the current power value of the optical signal from the laser diode, an operation unit outputting a target output value based on a comparison of the sampled current power value and a basic power value depending on a type of medium that is to receive the output of the laser diode, and a controller controlling the output of the laser diode based on the target output value.

Abstract: An optical disk device records data on a recordable or rewritable optical disk. The optical disk device comprises zone storing means for preliminarily storing locations of a plurality of zones set by dividing a recordable or rewritable area of the optical disk from an inner periphery thereof to an outer periphery thereof, position detecting means for detecting a position on the optical disk so as to record data at the position, judging means for judging which of the zones the position corresponds to by referring to the zone storing means, and controlling means for controlling the device to perform a data-recording by a CLV method to each of the zones specified by the judging means by setting a recording velocity and a recording power for each of the zones so as to enable the data-recording to provide an equal recording density to all of the zones.

Abstract: An apparatus and method for controlling an operation of recording data employed in an optical storage system is disclosed. The apparatus has a sampling-and-holding circuit, an operational amplifier, a plurality of gain amplifiers, and a plurality of switches. The apparatus operates under a short-term open mode, a long-term open mode, and a closed-loop mode sequentially in response to control signals and close/open statuses of the switches. A write-control signal is initialized by using a virtual ground effect within the short-term mode. In the long-term mode, the write-control signal is charged to a voltage level suitable for recording data onto a compact disk, while the charged write-control signal is employed to record data on the compact disk within the closed-loop mode.

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: The present invention provides a recording pulse generating apparatus capable of forming a recording pit having a proper shape even at the time of ultra-high-speed recording of, for example, 8× recording or higher. A recording controller 10 for generating recording pulse signals having lengths corresponding to ten kinds of lengths of pits formed at the time of recording information has a recording controller 10 for generating the recording pulse signals so that the amplitude of a recording pulse signal corresponding to a pit having a length of 4T changes from a first amplitude to a second amplitude, and generating the recording pulse signals so that the amplitude of a recording pulse signal corresponding to a pit having a length of 5T or longer changes from a third amplitude to a fourth amplitude and further changes to a fifth amplitude.

Abstract: The present invention is applicable to a recording apparatus of a CD or DVD, a recording method thereof and a recording medium, and an object of the present invention is to clearly record a second information such as characters and figures between two recording levels in an optical disk. The second information is recorded in a predetermined area in a radius direction and a angular direction on the optical information recording medium, and further, the second information is recorded according to a change of a pit width based on a change of power of the laser beam, a change of a pit length based on an on/off control of the laser beam, or a change of depression or bulge of the pit based on a change in the vicinity of the on/off control of the laser beam. Whereby it is possible to record the second information such as a watermark pattern or a visible image, which is capable of being confirmed by seeing a disk.

Abstract: An information storage medium having a plurality of information storage layers, each of which includes an optimal power control (OPC) area for obtaining an optimal recording condition. Optimal power control areas in odd-numbered and even-numbered information storage layers viewed from a direction in which light is incident upon the information storage medium are disposed one on another to not directly face each other. An actually usable area of an optimal power control area in each of the information storage layers varies depending on use circumstances of each of the information storage layers. Therefore, when an OPC area of one information storage layer performs OPC, this OPC does not affect another information storage layer. Also, an area of each of the information storage layers can be efficiently used.

Abstract: An optical disc apparatus for recording and reproducing information with respect to a rewritable optical disc includes a reproducing unit configured to reproduce information recorded on the optical disc by shining a laser beam having read power on the optical disc, and a recording unit configured to record information on the optical disc by alternately shining a laser beam having write power and a laser beam having bottom power lower than the write power on the optical disc at a portion where a mark is to be created, wherein the recording unit sets the bottom power to zero.

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.