Abstract: There is provided an optical disc drive comprises an optical pick-up including a laser diode (LD) and a laser diode driver (LDD) for driving the laser diode, a digital signal processor (DSP) including a write strategy circuit and low voltage differential signaling (LVDS) drivers for transmitting a produced write strategy signal, a circuit board having the DSP mounted thereon and including a line for transmitting the write strategy signal, a transmission line connecting the circuit board and the LDD and transmitting a write strategy signal, and differential resistors connected between differential lines of outputs of the LVDS drivers. Especially, a resistor having a resistance value in a range of 80 to 500? is inserted between the differential lines of outputs of the LVDS driver inside the DSP.

Abstract: An information recording/reproducing device which can record or reproduce the predetermined information quickly and properly is proposed. An information recording/reproducing device 10 detects recording condition of an area in radial direction of an optical medium 2 using the rotation angle in a layer 0 as a standard when recording given data in a layer 1 of the optical medium 2 and on the basis of the detection result, controls power of laser beam irradiated on the layer 1 to record or reproduce given recording data.

Abstract: An information storage medium and an apparatus for recording and/or reproducing the information storage medium are provided to control an optimal recording power without an influence of an optimal power control (OPC) area in a layer upon an OPC area in a different layer. The information storage medium includes at least one information storage layer including an optimal power control area for obtaining an optical recording condition. OPC areas in adjacent information storage layers are disposed within different radiuses of the information storage medium. Accordingly, even when the information storage medium is made eccentric or has a manufacturing error, a recording property of the information storage medium is prevented from being degraded due to an influence of an OPC area in an information storage layer upon an OPC area in an adjacent information storage layer.

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: 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: When recording or reading an optical disc having plural data recording layers, which data recording layer the light spot is focused on is detected to improve playback signal quality and signals written to the layer on which the light spot is focused are read more reliably. A convergent lens converges the laser beam on the optical disc, and a focus controller controls the focal point of the laser beam on the data layer. A tracking controller positions and tracks the focal point of the laser beam converged by the convergent lens on a track of the optical disc. A photodetector detects the reflected laser beam from the disc. A convergence detector then detects the convergence state of the laser beam emitted to the plural data recording layers. Based on output from the convergence detector, the laser driver is controlled to separately set beam power appropriately for each of the plural data layers of the disc during playback.

Abstract: In an optical disc device, the recording laser light power from a semiconductor laser is adjusted to a desired power. A front monitor PD is provided near the semiconductor laser LD of an optical pickup 16, and the recording layer light power is detected. A system controller 32 stores in memory an approximating equation for a correction coefficient for the recording power based on the detection signal characteristic when the recording laser light is a multi-pulse signal, uses the approximating equation to compute the correction coefficient for the desired recording power, corrects the detected signal level from the front monitor PD, and executes feedback control of the laser power emitted from the LD.

Abstract: The invention discloses an optical recording drive for recording data on an optical carrier such as an optical disk of the DVD or BD format. A radiation source is arranged to emit a write pulse train (80) for writing an optically detectable effect (90) i.e. a pit or mark. Photo detection means (10) detects a first reflected radiation beam pulse (R1) from a start time portion of the write pulse train (80) and generates a corresponding first signal (PS1) indicative of the power in the first pulse, the photo detection means (10) further detects a second reflected radiation pulse (R2) from an end time portion of the write pulse train (80) and generates a corresponding second signal (PS2) indicative of the power in the second pulse. By comparing (e.g.

Abstract: A recording and reproducing device (1) in which, when the power is turned off, the state of the power can be controlled to be in either one of a first power-off state and a second power-off state in which the recording and reproduction device (1) can be started faster than in the first power-off state. The recording and reproducing device (1) has a “first standby mode” during which the power state of the device is controlled to the first power-off state when the device receives a power-off instruction, and a “second standby mode” during which the power state of the device is controlled to the second power-off state when the device receives a power-off instruction. A power controller (30) makes, according to a setting time zone, the second standby mode active only for a predetermined time zone including the setting time zone.

Abstract: In an optical disc device that records information on a recordable optical disc having a power calibration area (PCA), recording operation is started with an input of a recording command. If an operating environment changes largely along with the recording operation, in order to perform an optimum recording power control, an optical pickup is shifted to the PCA, and the amount of an unused area in the PCA is determined. If an unused area in an amount to perform an optimum power control five times is not left, the optimum recording power control is stopped, and the recording operation is stopped. If left, the optimum recording power control is executed. Then, if a finalizing process is instructed, the finalizing process is performed. This avoids that, when performing a finalizing process of an optical disc after being subjected to recording, the finalizing process cannot be completed because the amount of an unused area remaining in the PCA is small.

Abstract: Disclosed is a laser pulse controlling circuit that, when the laser device is driven with laser pulses having the first and the second illumination levels, causes the first and the second illumination level setting units to set the first and the second illumination levels corresponding to a predetermined ratio of the first illumination level to the second illumination level, wherein the laser pulse controlling circuit, based on regularity that the relation between: a manipulated variable for causing the second illumination level setting unit to execute adjustment of the second illumination level; and the inverse of the ratio, with reference to the first illumination level, is a straight line that necessarily passes one point for a predetermined first illumination level, and that the slope of the straight line is proportional to an arbitrary first illumination level, calculates the manipulated variable that is correlated with the first illumination level corresponding to the optical disk, and with the inverse

Abstract: An automatic power control system, a down sampling circuit and a down sampling method. The automatic power control system is incorporated in an optical disc drive comprising a laser diode for receiving a control signal to generate a laser beam; and a photodetector for detecting the laser beam to generate an analog input signal. The automatic power control system comprises an analog-to-digital converter, a down sampling circuit, a comparator, and a digital-to-analog converter. The analog-to-digital converter converts the analog input signal to digital data. The down sampling circuit, coupled to the analog-to-digital converter, comprises a down sampler, a counter, and a controller. The down sampler receives a predetermined amount of digital data to generate representation data. The counter, coupled to the down sampler, calculates the amount of digital data, and resets the down sampler when the amount equals or exceeds the predetermined count.

Abstract: Laser power adjustment is performed using a power calibration area (PCA) until the PCA is used up. After the PCA is used up, an additional PCA is reserved at the next recording start position and laser power adjustment is performed using the additional PCA. When an additional PCA is reserved, the additional PCA exists between an information file recorded this time and the last one of information files recorded previously in terms of a physical format. However, information test-written into the additional PCA is not regarded as an information file and PMA information is generated only from the information file recorded this time by excluding the test-written information. As a result, a situation is obtained in which the additional PCA does not logically exist on the disk and there will never occur an inconvenient situation where the additional PCA is erroneously reproduced at the time of reproduction.

Abstract: According to one embodiment, to solve a new problem which has been produced due to adoption of a recording method using relaxation oscillation, the laser output control device suppresses unnecessary relaxation oscillation while increasing an averaged light quantity between recording pulses to obtain reflected light quantity which is necessary for tracking and focus controlling. A laser modulation control circuit includes a recording pulse output unit which outputs recording pulses for making relaxation oscillation as the recording pulses, a bias current output unit which outputs a constant bias current between the recording pulses, and a high-frequency overlap unit which overlaps the high-frequency signal on the constant bias current between the recording pulses, and controls so as to have times at which current values at a start edge and an end edge of the high-frequency signal are almost consistent with a value of the constant bias current.

Abstract: A drive apparatus including: a superposition device which superposes a superposition signal on a drive signal for driving a light beam emission device that emits a light beam and which outputs the drive signal on which the superposition signal is superposed to the light beam emission device, a reference clock signal generation device which generates a reference clock signal, a frequency change device which changes a frequency of the superposition signal based on a quality index for indicating a quality of a reproduction signal that is obtained from a reflection light that is the light beam reflected on a record medium, a phase locked loop device which controls the changed frequency so as to be constant by a feedback method in use of the generated reference clock signal.

Abstract: A plurality of types of recording pulse control rules for which the recording pulse waveform is determined according to the information signals to be recorded are stored in advance in an optical disk. When recording to the optical disk, information is recorded using a recording pulse where, due to the focused laser beam, the temperature in the recording layer cools more rapidly at a second information recording layer closer to the side where light is incident than at a first information recording layer farther away from the side where light is incident.

Abstract: An information storage medium on which data is recorded after performing optimum power control (OPC) and a method and apparatus to record/reproduce data on/from the information storage medium, wherein the recordable information storage medium has a plurality of recording layers and a pickup irradiates a beam onto the information storage medium, utilize operations of: recording data on at least a portion of a recording layer through which a test beam to find an optimum recording power passes before performing optimum power control (OPC) on a desired recording layer and performing OPC on the desired recording layer. The method and apparatus allow data to be recorded after performing a test to determine an optimum recording power, thus providing effective recording/reproducing quality.

Abstract: According to one embodiment, a plurality of conditions are simultaneously recorded for a power in a combination of power and strategy conditions which are parameters to be adjusted, such that the number of seeks required for a feedback can be reduced, and time for an automatic adjustment required at a rising edge can be reduced.

Abstract: An optical disc recording medium is irradiated with laser light having a predetermined laser power to deform an irradiated portion of a substrate into a protruding portion. Since the substrate is deformed so as to have protruding portions, a reflecting layer arranged on the substrate is also deformed so as to have protruding portions. For a pit, the deformed state of a protruding portion allows to obtain a reproduced signal level equivalent to that in each land. For a land, the deformed state of a protruding portion allows to obtain a reproduced signal level equivalent to that in each pit. Since the deformed state of each protruding portion can be controlled on the basis of the power of the laser light for irradiation, pit-to-land deformation and land-to-pit deformation can be performed by setting the laser power. Thus, recorded data can be rewritten on the optical disc recording medium recorded with the data using a combination of pits and lands formed in the substrate.

Abstract: Provided are a method and apparatus for performing a writing test using charge pumps in an optical disk reproducing/recording apparatus. In the apparatus for performing the writing test, an optimum power control (OPC) determining unit determines a phase of a radio frequency signal using a reference voltage, and generates a corresponding OPC voltage; an analog-to-digital converter (ADC) unit converts the OPC voltage into a digital signal; and a micom controls a power control unit according to the digital signal, to appropriately control laser power.

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: In the present invention, there is provided an information recording apparatus for recording information to an optical disk including: a data recording section configured to record data while changing laser power levels successively; a data reproduction section; and an optimum recording power calculation section configured to calculate an optimum recording laser power level by evaluating the quality of a reproduced signal, wherein the data reproduction section performs data reproduction based on a PRML procedure, and based on PRML reproduction information, the optimum recording power calculation section finds an E error formed by the difference in a Euclidean distance squared between the most and second most likely path metric values in order to calculate E jitter values, the optimum recording power calculation section further calculating as the optimum recording power a laser power level corresponding to the recorded data of which the E jitter value is the smallest.

Abstract: In an optical disk, a substrate has main data recorded in the form of a combination of pits and lands on one side thereof, and at least a reflective layer and cover layer are stacked on the substrate to cover the pits and lands on the substrate. To the optical disk, sub data is recorded in the form of marks formed by irradiating writing-power laser light to the reflective layer. The marks are formed so that reading signal level will be raised where the marks are formed while it will be lowered where the marks are formed in a counterfeit disk produced based on an authenticated disk, namely, the reading signal level where the marks are formed is different in polarity between in the authenticated and counterfeit disks. Further, in a player for the optical disk, discrimination is made between the authenticated and counterfeit disks by detecting the sub data recorded in the optical disk and judging whether the value of the detected sub data has been read at a correct polarity.

Abstract: An optical reproducing device is provided with predetermined length mark signal measurement means which measures amplitude values of a 2T mark and an 8T mark, which are a short reproducing power control mark and a long reproducing power control marks, respectively, from information data recorded in an magneto-optical disk. Reproducing power of a light beam is controlled by a laser power control circuit, based on the amplitude values of the 2T mark and the 8T mark. The predetermined length mark signal measurement means detects a specific pattern including the 2T mark from a bit arrangement pattern of the information data, and measures the amplitude value of the 2T mark correponding only to the 2T mark included in the specific pattern. This structure can provide an optical reproducing device which can maintain the reproducing power at an optimum value and reduce the probability of reading errors, without reducing the utilization ratio of an optical recording medium.

Abstract: An optical information recording device, which emits a first beam to one side of an optical information recording medium and a second beam to the other side and forms a recording mark or a hologram by putting together the first and second beams, includes: a section that collects and emits the first beam to the recording medium; a section that moves a focal point of the first beam so that the focal point is positioned at a target depth and is aligned with a target track; a section that makes a diameter of the second beam around its focal point larger than a diameter of the first beam around its focal point; and a section that puts the focal point of the second beam at the target depth and moves the focal point of the second beam such that the second beam strikes the target track.

Abstract: One embodiment includes providing control information, wherein the control information includes one or more recording speed flags indicating respectively whether one or more recording speeds are applicable to each of the recording layers. The control information also includes write strategy information depending on each of the applicable recording speeds, and the control information is recorded on a specific area of the recording medium.

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: The present invention provides a deficiency detecting apparatus that can accurately detect dusts and deficiencies on an optical disk even when an emitting power of a laser light source changes. The deficiency detecting apparatus is provided with a deficiency detecting section for detecting deficiencies or the like on an optical disk by reflected light, and a power adjusting section for adjusting an emitting power of a laser light source to be an optimum value. The deficiency detecting section can accurately detect the deficiencies on the optical disk even when the laser power changes by comparing a threshold value, which is determined in accordance with the adjustment result of the power adjusting section, with a value in accordance with the reflected light.

Abstract: Accurate calibration of recording power is performed without exceeding a rated output value of a laser diode even if recording speed is increased and high recording power is required. An information recording apparatus records information on an information recording medium such as a DVD-R/RW or a DVD+R/RW by applying a laser light onto the information recording medium. A pickup has a laser light source. A light receiving unit for detecting the amount of light by receiving the laser light emitted from the laser light source is provided, and the power of the laser light is controlled based on the power of the detected laser light. Before the actual information recording, a test emission is performed during calibration to determine an adequate recording power, and the emission duty of the laser light is controlled within the range not exceeding the rated output value of the laser light source.

Abstract: A disk drive data storage system comprising at least one data storage disk and a sensor assembly proximate the data storage disk. The sensor assembly further comprises circuitry for writing data to the data storage disk and circuitry for reading data from the data storage disk. The system also comprises circuitry for controlling the circuitry for reading data during different time periods so that the circuitry for reading data consumes different levels of power while the circuitry for writing data is writing data to the data storage disk.

Abstract: An optical disc device and recording power control method that can ensure the recording quality of data recorded on an optical disc are suggested. When recording data on an optical disc, data recorded on the optical disc is reproduced periodically; a ? value, an index of recording quality of the data on the optical disc, is obtained based on a waveform of the reproduced data; a correction factor of recording power is calculated based on the obtained ? value, and the recording power is corrected according to the correction factor; at the same time, a recording area of the optical disc is divided into a plurality of zones and the correction factor for each zone is managed; and the recording power is corrected according to the correction factor of the zone where data is to be recorded next on the optical disc.

Abstract: The present invention relates to a recording apparatus and a corresponding recording method for recording marks in an information layer (601) of a record carrier (60) by irradiating the information layer by means of a radiation beam, said information layer having a phase reversibly changeable between a first phase and a second phase, wherein a mark is written by a sequence of one or more write pulses, the number of write pulses of the sequence for writing a mark of length NT, T being the length of a reference clock, being determined by application of a predetermined write strategy.

Abstract: According to one embodiment, there is provided an optical disc apparatus including: a recording unit forming a mark and a space on the optical disc by using a laser beam having a set recording power level and, thus, recording data on an optical disc; a reproduction unit reproducing the mark and the space formed on the optical disc; a change amount calculating unit calculating an amount of change in an amplitude of readout signal for the space reproduced by the reproduction unit; and a recording power determining unit determining an optimal recording power level of the laser beam so as to set the calculated amount of change in the amplitude of the readout signal within a predetermined range.

Abstract: According to one embodiment, there is provided an optical disc apparatus including: a recording unit forming a mark and a space having a predetermined code length by using a laser beam and, thus, recording data on an optical disc; a crest value acquiring unit acquiring a crest value of the mark and the space for each code length from a readout signal of the optical disc; an asymmetry calculation unit calculating asymmetry value for each code length from the crest value; and a recoding parameter determining unit determining, based on a linear characteristic between the asymmetry value for each code length and the recording power level, an optimal recording parameter including an optimal recording power level of the laser beam, the recoding parameter determining unit determining the optimal recording power level to set the asymmetry value for each code length within a predetermined range.

Abstract: A temperature compensating method and apparatus uses a front sensor to measure a first power of a light-emitting unit emitting a light, and a thermal sensor to measure the temperature of the light-emitting unit. The temperature is inputted into an I/O unit to figure out a second power from the equations of the temperature and power. Then, the first and second powers are inputted into a controller to adjust the power of the light-emitting unit, or the second powers are inputted into a write strategy to change an output clock to adjust the energy of the light without changing the power of the light-emitting unit. The optical disc device has the effect of the temperature compensation.

Abstract: Provided are an electric field read/write device and a method of driving an electric field read/write device. The method including an electric field read/write head comprising a resistance region disposed between a source region and a drain region and a writing electrode disposed on the resistance region, wherein the method includes: applying a controlling voltage to the writing electrode, wherein the controlling voltage is smaller than a threshold voltage which causes polarization of a recording medium, and reproducing data recorded in the recording medium according to change of an amount of a current flowing through the resistance region according to a polarization direction of electric domains of the recording medium.

Abstract: A recording and reproducing method is provided in which information can be recorded and reproduced correctly using a simple circuit structure, even with a high transfer rate, and a test record can be performed efficiently in a short time. A laser driving circuit 6 makes power levels of a front end pulse and a rear end pulse different from a power level of a middle pulse, and a record signal edge correction circuit 5 corrects an edge position of a recording pulse.

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: 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: There is provided an information recording device for recording record information onto an information recording medium having a plurality of recording layers. The information recording device includes: write elements capable of writing record information into the recording layers; control elements for controlling the write elements to write first boundary information or second boundary information (107a-0) having a smaller recording capacity than the first boundary information at the end of record information recorded in one of the recording layers; and detection elements for detecting an empty capacity of the data area in that recording layer. The control elements controls the write elements to write the first boundary information at the end if the empty capacity is equal to or greater than a first threshold value and the second boundary information at the end if the detected empty capacity is smaller than the first threshold value.

Abstract: An information recording device comprising a recording unit that records recording information by applying a laser beam to an information recording medium having a first recording layer for recording recording information by being irradiated with a laser beam and a second recording layer for recording recording information by irradiating with a laser beam via the first recording layer, a calculating unit that calculates an optimum laser beam power when, by using the recording means, trial-recording trial information is recorded by irradiating the second recording layer with a laser beam via a recording-information-unrecorded recording area in the first recording layer and recording information is recorded by irradiating the second recording layer with a laser beam via a recording-information-recorded recording area in the first recording layer, and a control unit that controls the recording unit.

Abstract: According to an embodiment, there is provided an optical storage media recording/reproducing apparatus for calibrating an amount of light energy output by the recording/reproducing apparatus during a recording operation, the recording/reproducing apparatus comprising: a reproducing unit to read unique property information from a writable optical disc inserted into the apparatus, which was pre-recorded on the disc during its manufacture; a controller to access stored data concerning optimum test writing parameters relevant to the recording/reproducing apparatus using the unique property information; and a recording unit to write test data on the disc in accordance with the accessed stored data concerning the optimum test writing parameters.

Abstract: This invention relates to controlling the power states in a multimedia system comprising a multimedia connector box including a multimedia source interconnected to a transmitter module, and a multimedia device including a receiver module interconnected to a multimedia sink, wherein the transmitter and the vice via multimedia interfacing means. A signal detector detects the signal activity between the power sources of the multimedia system for determining the current power state of the power sources, and a power switching mechanism adapts the power states of the transmitter and receiving modules to the power states of the power sources.

Abstract: In an information recording method and apparatus, when performing recording by using multiple pulses defined by erase powers Pe1 and Pe2 for forming a space part between mark parts, the set values of the erase powers Pe1 and Pe2 are updated at predetermined intervals in accordance with a recording linear velocity.

Abstract: If regeneration is not performed normally when data is regenerated from a medium, a read retry processing unit changes the intensities of the laser beam and of the regeneration magnetic field respectively to prearranged stages to perform the regeneration again. A regeneration condition change unit remembers the regeneration sector number for one read command from the higher order. When retry occurs, the regeneration condition change unit counts the number of the sectors for each stage which can be regenerated at each stage, and by providing a coefficient for each stage in advance, changes the default regeneration condition using the sum of products of the coefficients and the number of the counted regenerable sectors.

Abstract: An optical pickup used to record information on and/or reproduce information from an optical recording medium, the optical pickup including an optical module to emit a light beam; and a front photo-detector to monitor power of the light beam; wherein the optical module is coupled to the front photo-detector so that a fixed distance is maintained between the optical module and the front photo-detector.

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 information recording method is provided, which comprises the steps of (a) determining a power level of a pulse sequence, (b) generating the pulse sequence based on the power level determined, and (c) irradiating an information recording medium with light corresponding to the pulse sequence generated to record information represented by at least either a recording mark or a space onto the information recording medium. The pulse sequence comprises a multi-pulse chain for forming the recording mark. The multi-pulse chain comprises a plurality of pulses having a peak power level. In the step (a), a bottom power level is determined between the peak power level and an erase power level which is lower than the peak power level while keeping an interpulse spacing constant.

Abstract: A laser power control system and method used in an optical disc writer. According to a write power value, the laser power control system drives a laser to output a write power through a first channel. According to a proportional value, the laser power control system drives the laser to output an overdrive power through a second channel. By using a close loop control of the laser power control system, the write power and the overwrite power are independent of the temperature changes.

Abstract: Information processing equipment is so constructed that the power consumption of a disk drive for hard disks, optical disks, or the like can be reliably and sufficiently reduced. The host CPU (120) of an information processing unit (100) forms a command for changing the power consumption mode of a HDD (200) based on the state of control on the HDD (200). The host CPU supplies the command to the HDD (200) through a media controller (106). When the HDD (200) accepts the command, it changes its power consumption mode according to the instruction from the information processing unit. Thus, the information processing unit can control the power consumption mode of the HDD (200) based on the state of control on the HDD (200).