Abstract: A reproducing apparatus for reproducing information recorded on an optical recording medium including a disk-like substrate, a spiral or concentric-shaped groove structure along a track formed on the substrate, wherein the groove structure is wobbled in a radial direction of the medium. The wobbled groove structure is utilized for recording of recording data, and the track is divided into a plurality of recording units in the track direction by at least one radial boundary line. The apparatus includes an irradiation source for irradiating a light spot on the optical recording medium, an optical detector for detecting a reflected light from the medium, and a reproducer for reproducing information by using a signal from the detector.

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

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

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

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

Abstract: The present invention comprises systems and methods related to monitoring of energy usage on a power line. In a preferred embodiment, this system comprises (a) an electronic microprocessor-controlled digital electricity metering device coupled to the power line and comprising a non-volatile non-battery-powered data-storage device, wherein the metering device is capable of interval metering and of receiving a data request and transmitting data in response to the request over the power line; and (b) a data collector (preferably, a transponder) coupled to the metering device via the power line. The data collector is preferably capable of (i) receiving data from and transmitting data to the metering device over the power line, (ii) storing data received from the metering device over the power line, and (iii) receiving data from and transmitting data to a remotely located computer (preferably, a billing computer).

Abstract: An optical disk device for writing data onto an optical disk having a wobble track comprises an optical pickup for irradiating laser light of a writing power and laser light of a replaying power onto an optical disk and for converting return light from the optical disk into an electrical signal, a filter for extracting a wobble component contained in the return light signal when the laser of a writing power is irradiated, a processor for detecting the direction of track deviation based on the phase of the wobble component, and an actuator for driving the optical pickup in the width direction of the track based on the direction of the track deviation in order to control the tracking. Because the phase of the wobble component differs for a case when a light spot is deviated radially inward and for a case when a light spot is deviated radially outward, the direction of the track deviation can be detected based on the phase of the wobble component and the tracking can be controlled during data writing.

Abstract: An optical disk apparatus for recording test data onto an optical disk while changing the level of recording power and determines the optimum recording power with reference to the quality of a reproduced signal of the test data. A modulation degree or a ? value is calculated from a reproduced signal of the test data, and the gradient of a change of the modulation degree or the ? value relative to the recording power Pw is calculated. Further, a target recording power is determined utilizing an area where the gradient of the change is relatively sharp, and the optimum recording power is determined based on the target recording power.

Abstract: An optical disc recording method comprises the steps of: setting a recording parameter function representing a relationship between a recording velocity for recording data to an optical disc and a parameter for optimally controlling a recording power controlling waveform for controlling a recording power of a light beam irradiated to the optical disc for recording the data; obtaining an optimal value for the parameter by executing a test recording at one recording velocity or at a plurality of recording velocities to a test area of the optical disc before actual data recording to the optical disc; correcting the recording parameter function in accordance with the obtained optimal value for the parameter; deriving the parameter corresponding to a recording velocity from the corrected recording parameter function; and recording the data by irradiating a light beam of the recording power controlling waveform to which the obtained parameter is applied.

Abstract: A method is designed for controlling a power of a laser beam irradiated onto a track of an optical disc for recording of data at a given linear velocity.

Abstract: The invention relates to a method and recording device for selecting an optimal write strategy for a specific type of optical recording disk. Such an optimal write strategy is selected even when the optical recording disk is of a type that has not been previously encountered or when the optical recording disk is otherwise unrecognized by an optical disk drive. The optimal write strategy and associated settings are selected from a set of write strategies stored in a disk drive. The disk drive bases its selection of the write strategy on the performance results of test writings conducted on the optical disk. The method entails testing the write strategies first at the maximum possible write speed and if necessary, at successively lower speeds until a write strategy that achieves a minimum acceptable write quality is identified or until the minimum write speed is reached. The selected optimal write strategy may be stored in the recording device or, alternatively, on the optical recording disk itself.

Abstract: An attempt is made to prevent an adequate recording power detection lag from being generated according to data from a defective area at trial writing, by detecting a defective area portion based on a fluctuation of return light when a trial write recording mark is formed, recording it in another portion under the same conditions as the detected portion, and using the information on the recorded area instead of the area in which the defective area was detected at reproduction of the trial writing.

Abstract: An optical recording device includes a recording condition determining section for determining recording conditions for a track by performing test writing with respect to the track which is, for example, either a land or a groove of a magneto-optical disk, a recording condition computing section for performing computation in accordance with computation-use information based on the recording conditions for the track so as to determine recording conditions for the other track, a track switch section for switching tracks to be used for test writing, and a computation-use information managing section for correcting the computation-use information based on respective results of test writing before and after the switch, thereby determining recording conditions for one of the tracks in short time by computation, while, because the computation-use information is corrected based on the results of test writing, improving accuracy in recording conditions obtained by computation.

Abstract: An optical information recording apparatus includes an emission output information acquisition section for acquiring information about a drive current employed for controlling a beam output from an information recording section; a cooling determination section for determining whether to cool the information recording section in accordance with the information about the emission output acquired by the emission output information acquisition section; and a cooling execution section for cooling the information recording section when the cooling determination section has determined that cooling should be performed.

Abstract: High efficiency recording is carried for recording recording data generated by a second recording system signal processing circuit 11 to a recording disc corresponding to an existing first standard, and in this case the recording data generated by the second recording system signal processing circuit 11 is selectively recorded to the first recording disc based on one of a first or a second standard. In this way, high efficiency recording is possible regardless of whether data has a recording format corresponding to the first standard or the second standard.

Abstract: A method for recording information is disclosed in which an information recording medium is irradiated with a recording energy beam power-modulated into at least a record power level and a record-ready power level lower than the record power level. 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. Also, only in the case where the energy beam is modulated by the power lower in power level than the record-ready power level after the last pulse of the energy beam pulse train including at least one pulse for forming a mark portion and the mark portion is followed by a space portion of a predetermined length, the particular radiation energy of low power level is reduced as compared with when the mark portion is followed by a space potion of a different length.

Abstract: A high-density optical recording medium and method of recording data on the optical recording medium. The optical recording medium includes a plurality of data recording/reproducing surfaces having reflectances for light passing through a pit area, a land/groove area, and a land/groove area on which data are recorded, of a data recording/reproducing surface included between a light source for emitting light and a recording/reproducing surface selected from the plurality of data recording/reproducing surfaces, the reflectances satisfy the expressions r1?r2?r3 and {(r1?r3)/r3}?0.2, where r1, r2 and r3 are the reflectances of the pit area, the land/groove area and the land groove area on which data are recorded, respectively.

Abstract: A method, for tuning a plurality of write strategy parameters of an optical storage device, includes: detecting a plurality of lengths, each length corresponding to a pit or a land on an optical storage medium accessed by the optical storage device; performing calculations according to the lengths and a plurality of data set types to generate a plurality of calculation results respectively corresponding to the data set types, each of the data set types corresponding to a combination of at least a specific target pit length and a specific target land length or a combination of at least a specific target land length and a specific target pit length, the combination corresponding to a specific write strategy parameter; and utilizing the calculation results for tuning the write strategy parameters corresponding to the data set types, respectively.

Abstract: A method for recording data in an optical recording medium according to present invention is constituted so that data are recorded in an optical recording medium including a light transmission layer and two recording layers by projecting a laser beam whose power is pulse-like modulated between a recording power and a bottom power lower than the recording power onto the optical recording medium from a side of the light transmission layer and forming recording marks having different lengths in the recording layers and that when a recording mark having a longer length than that of the shortest recording mark is to be formed in the recording layers by modulating the power of a laser beam using a single pulse, a time of raising the power of the laser beam to the recording power is delayed relative to a time of raising the power of the laser beam to the recording power when the shortest recording mark is to be formed.

Abstract: An optical disk recording and reproducing apparatus operates in a read mode for controlling a laser driver to maintain a laser power at a target read level so as to read a signal from an optical disk, and operates in a write mode for controlling the laser driver to alternate the laser power between a target write level and a target bottom level comparative with the target read level so as to write a signal into the optical disk. In the write mode, a value obtained by sampling and holding the bottom level is set as the target value of a bottom level, and a bottom level control signal is outputted according to a difference between this target value and the detected value of the bottom level. Thus, the laser power control can be performed without any errors being generated even if an offset has occurred in the detected bottom power. Thus, the bottom laser power can be maintained constant.

Abstract: An information recording medium includes a data area for recording data; and a drive information area for recording at least one piece of drive information. The data area is divided into a plurality of segmented areas in a radial direction of the information recording medium. Each at least one piece of drive information includes a recording and reproduction condition corresponding to at least one of the plurality of segmented areas.

Abstract: A light source drive which modulates a light source so as to cause the same to emit a light, includes: a superposition current generation part which generates a superposition current approximately corresponding to a charging/discharging current needed for a capacitance occurring in parallel to the light source for a predetermined time period near at least one of a rising-up part and a decaying-down part of a waveform of a drive current for the light source; and an addition/subtraction part which adds to or subtracts from the drive current the superposition current generated by the superposition current generation part.

Abstract: An information recording method of recording information, in which laser light is applied to a recording medium while depending on predetermined information said laser light is modulated and the intensity of said light is controlled to form recording mark areas at which reflectivity of said recording medium changes, depending on the intensity of said applied light, wherein before starting data recording, said light is applied to said recording medium at predetermined light intensity, reflection light from said recording mark areas of said recording medium is received, the amount of said reflection light is detected, and a light intensity controlling reference value is calculated on the basis of the amount of said detected light, and during data recording, reflection light from said recording mark areas of said recording medium is received, the amount of said reflection light is detected, and a light intensity controlling detection value is calculated on the basis of the amount of said detected light, correcte

Abstract: The present invention comprises systems and methods related to monitoring of energy usage on a power line. In a preferred embodiment, this system comprises (a) an electronic microprocessor-controlled digital electricity metering device coupled to the power line and comprising a non-volatile non-battery-powered data-storage device, wherein the metering device is capable of interval metering and of receiving a data request and transmitting data in response to the request over the power line; and (b) a data collector (preferably, a transponder) coupled to the metering device via the power line. The data collector is preferably capable of (i) receiving data from and transmitting data to the metering device over the power line, (ii) storing data received from the metering device over the power line, and (iii) receiving data from and transmitting data to a remotely located computer (preferably, a billing computer).

Abstract: Electric power consumed by a laser diode when an optical disk or magneto-optical disk is played back is reduced. A laser diode control circuit (6) causes the laser diode to emit continuously rather than intermittently, even if a PCK signal is supplied to the laser diode control circuit (6), when an optical display player or magneto-optical disk drive does not yet stabilize and is being pulled into a phase-locked state. When the focus is locked, the player is in a phase-locked state, and the operation is stable, a mode-switching circuit (9) included in the laser diode control circuit (6) switches the mode of operation from continuous operation to intermittent operation according to an FLOCK signal. The frequency of the PCK is multiplied by a frequency multiplier circuit (7), and the pulse width is adjusted by a pulse width-adjusting circuit (8). A laser diode driver circuit (10) produces intermittent current of this adjusted pulse width. The laser diode is started to emit intermittently.

Abstract: An information recording/reproducing apparatus of the present invention includes: a light source for emitting a first light beam having a predetermined light power Ppre; a determination section for determining the number of recording layers included in the information recording medium; a light beam transmission adjustment section for adjusting the quantity of the first light beam transmitted therethrough; and a light condensing section for condensing the first light beam on the information recording medium. When the information recording medium has one recording layer, the adjustment section adjusts the predetermined light power Ppre so as to be a first light power P1. When the information recording medium has two recording layers, the adjustment section adjusts the predetermined light power Ppre so as to be a second light power P2. The predetermined light power Ppre, the first light power P1, and the second light power P2 satisfy the relationship of P1<P2?Ppre.

Abstract: The present invention relates to an optical head device and an optical disk unit using the same. The optical head device includes a relay lens control unit to control at least one of lenses of a relay lens unit based on an output signal outputted from a first optical detector and a power control circuit to control an intensity of a light beam emits from a light source.

Abstract: An optical recording power controlling apparatus and method, in which the determination conditions for received Non Return to Zero Inverted (NRZI) data and the varying range of the optical recording power level are set depending on the multiple-speed of recording and the type of an optical medium, and the varying range of the optical recording power level is controlled so that optical recording power provided to a light emitting device is optimal for the multiple-speed of recording and the type of an optical medium. In the optical recording power controlling apparatus, a system control unit sets the discrimination conditions of received data to be recorded and the varying range of the optical recording power level, depending on the multiple-speed of recording and the type of an optical medium.

Abstract: An optical disk apparatus that records data on an optical disk whose linear velocity is not constant. The optical disk apparatus includes an optical pickup that irradiates a laser beam of a recording power on the optical disk, converts light reflected from the optical disk into an electric signal; a detector that detects a level of the reflected light signal; and a controller that controls a recording power such that the reflected light signal level matches a target value set according to the linear velocity. When adjusting the recording power such that the reflected light level matches the target value, the target value is not set to a constant level, but set in accordance with the linear velocity. Target values at different linear velocities differ and, with this configuration, an appropriate target value is set and an appropriate recording power corresponding to the linear velocity is obtained.

Abstract: A method and related apparatus for storing program code and optimized power calibration (OPC) data in the same non-volatile memory is provided. The method is used for accessing OPC data from an optical discrecorder. The optical disc recorder is capable of obtaining OPC data of an optical disc by executing an optimized power calibrating process so as to record data onto the optical disc. The optical disc recorder has a first memory with a program code being stored therein and a second memory. The method includes registering the program code in the second memory, and writing the OPC data of the optical disc to the first memory according to the program code registered in the second memory.

Abstract: Recording power is optimized in an optical disk apparatus by recording a test signal on an optical disk while varying the recording power, and then determining a ? value from a reproduced signal. A controller calculates a change in ? value with respect to the recording power. A target ? value is selected from those within the range wherein the ? value varies linearly. The recording power by which the target ? value is produced is selected as an optimum recording power for recording data on the optical disk. A modulation factor or parameters other than the ? value may also be used as an indication of quality of reproduced signals.

Abstract: An optimal power calibration (OPC) method calibrates writing power for an optical disc. The optical disc includes a power calibration area, with a plurality of counting units and test blocks. The OPC method includes generating a plurality of first power levels by using an indicated power, selecting a plurality of second power levels from the first power levels, recording test data onto test blocks with the second power levels, reading the test blocks, and generating data signals and first beta values. The method further includes generating estimated optimal power by a calculating algorithm, generating a plurality of third power levels by using the estimated optimal power, recording test data onto test blocks with the third power levels, reading the test blocks, and generating data signals and second beta values. Optimal power is calculated by using the estimated optimal power, the first beta values, and the second beta values.

Abstract: Apparatus and method of power compensation and optical device using the same. The power compensation apparatus is used to compensate a write power of the optical device. The power compensation apparatus has a signal extraction circuit, a gain setting unit, and an adder. The signal extraction circuit is used to extract a absolute value of a portion of a servo error signal over a threshold voltage. The gain setting unit is used to generate a compensation signal using a gain thereof to adjust the absolute value of the portion of the servo error signal over the threshold voltage. The adder is used to add the compensation signal into the write power.

Abstract: The present invention provides a method and system for calibration of writing to an optical medium. The method includes: sampling marks in a calibration area of the optical medium; and converting the sampled marks into a digital format utilizing an ADC, the ADC also utilized by a servo control. The present invention provides a controller with an integrated servo and recording processor which allows a single ADC to be used for converting sample marks used in calibrating the writing to an optical media. No separate subsystem for converting sample marks is thus necessary. Less components are required, reducing the cost of manufacturing the controller. With less components, the risk of component failure is reduced as well.

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: A crosstalk amount of a rewritable optical disk at an optimum recording power is stored, then the data recorded on the rewritable optical disk are reproduced upon overwriting the data on the rewritable optical disk, then a crosstalk amount in a reproduced signal is detected, and then this crosstalk amount is compared with a reference crosstalk amount. Since the crosstalk amount has such a characteristic that such crosstalk amount is increased larger as a width of a pit is thickened, i.e., a recording power is increased higher, it is possible to detect a recording power value by comparing the crosstalk amounts. As a result, the crosstalk amounts of both data are compared with each other by utilizing this characteristic, and then the recording conditions such as an erasing power, the recording power, etc. are changed in response to the compared result to overwrite the data.

Abstract: An information-recording method and an information-recording medium which make it possible to improve overwrite characteristics in the high speed recording, especially archival overwrite characteristics for overwriting information after retaining the medium in a high temperature environment for a certain period of time, and an information-recording apparatus based on the use of the same are provided.

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

Abstract: A storage apparatus, capable of record or reproduce of an optical information recording medium in which ROM information is recorded with phase pits and RAM information is recorded on top of a recording region of the phase pits, has a main controller that, when the output of the recording information detection system—a system for detecting reflected light of a laser beam from the optical information recording medium and generating signals corresponding to ROM and RAM information—simultaneously contains ROM and RAM signals corresponding to ROM and RAM information, performs negative feedback control of a semiconductor laser emission using ROM signal in the output of the recording information detection system and performs control so as to obtain read-out and played-back ROM signal from the output of an optical intensity detection system for detecting the intensity of the laser light.

Abstract: A reproduction method for a multi-level optical recording medium according to the present invention rotates an optical recording medium, on which recording data has been recorded according to a multi-level recording method which sets several levels for light reflectivity of virtual recording cells, emits a reproduction laser beam towards the optical recording medium, and reproduces the recording data based on an electric signal generated in accordance with a received level of reflected light, the method setting the emission power of the reproduction laser beam in a range of 1.0 mW to 2.5 mW inclusive when the optical recording medium is rotated at a linear velocity in a range of 9 m/s to 25 m/s inclusive. By doing so, it is possible to improve the read accuracy for recording data while suppressing the reproduction deterioration of the optical recording medium to a level where deterioration effectively does not occur.

Abstract: A method and apparatus to record data on an optical recording medium include generating a recording waveform having an erase pattern comprising a predetermined pulse having a high level which is higher than an erase power level and having a low level which is lower than the erase power level.

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: Optical pick-up units and laser drivers are disclosed, which can be used in various types of information recording/reproducing apparatuses, such as, but not limited to, DVD and CD drives, DVD camcorders, and DVD video recorders. A laser driver integrated circuit (LDIC) includes an automatic power controller, a running optical power controller, and a write strategy generator. The LDIC can be part of a chip-set, to be located on an optical pick-up unit (OPU). The chip-set can also include a power monitor integrated circuit (PMIC) to monitor the laser diode, and a photo-detector integrated circuit (PDIC) to detect light produced by the laser diode. The PMIC and the PDIC each include their own offset, gain and sample-and-hold circuitry.

Abstract: An optical recording method is designed for recording data on a recordable optical disk by use of a laser beam of a present recording apparatus under a desired recording condition. The method detects identification information which is reserved in the optical disk and which is indicative of a type of a previous recording apparatus. The detected identification information is compared with a plurality of identification information which are previously stored in correspondence to various types of recording apparatuses. As results of the comparison, the method determines whether the detected identification information matches with one of the stored identification information which does not correspond to the type of the present recording apparatus. Upon the determining of matching, the method retrieves a recording condition which is previously stored in association with the matching identification information.

Abstract: A device for recording information on an optical disc so as to improve the recording quality of the information when a recording operation has just started. The recording device includes a luminous element radiating a light for recording information on the optical disc; a radiation intensity controller constantly controlling an intensity of radiation of the light radiated by the luminous element; a constant outputting unit providing a constant energy to the luminous element; a selector selectively selecting one of the outputs of the intensity of radiation controller and the constant outputting unit; wherein, the selector selects the output from the constant outputting unit during a predetermined duration from a starting time of recording the information on the optical disc, and selects the output from the intensity of radiation controller afterward.

Abstract: An automatic power control (APC) apparatus reducing time necessary for stabilizing an APC circuit at the initial stage of automatic power control of a disc drive is provided. The APC circuit is designed such that a voltage of a predetermined percent of an expected output voltage is previously added to an APC output voltage of the APC circuit of a laser diode, thereby greatly reducing a stabilizing time necessary for stabilizing an APC output voltage at an initial stage in a write or read mode. Therefore, the loss of data in a high speed write or read mode can be reduced. Particularly, the loss of data in a high speed write mode can be greatly reduced.

Abstract: A reproduction power control device includes: an adapter/equalizer for adapt and equalizing a digital reproduction signal to a predetermined frequency characteristic so a post-equalization reproduction signal; and a reproduction power control unit for, based on an equalization amount in the adaptation and equalization by the adapter/equalizer, detecting an error between a current reproduction power and an optimal reproduction power and controlling a reproduction power of laser light so as to bring the error closer to 0. In this manner, it becomes possible to offer a reproduction power control method, a reproduction power control device, and a record reproducing device incorporating the same, capable of reproduction power control without reducing the user area on a recording medium.

Abstract: An optical reproduction apparatus in accordance with the present invention has a gain control circuit for controlling a gain of an amplifier circuit which amplifies a reproduction signal in accordance with amplitudes of the reproduction signal from an optical recording medium. The amplitude is sent to a power control calculation circuit which controls the reproduction power of a light beam in accordance with the amplitude. The gain control circuit has a slower response speed than that of the power control circuit at least during a period when the power control circuit controls the reproduction power. This allows to provide an optical reproduction apparatus that can realize the stable reproduction power and automatic gain control even to the unevenness of the amplitudes of the reproduction signal.

Abstract: An information recording method records information on an optical disk by a recording pulse signal of an optical beam that is emitted from an optical source. A recording channel clock period T is changed depending on a change of a recording linear velocity so that a recording linear density is maintained approximately constant. In addition, a shape of a pulse waveform of a top heating portion of the recording pulse signal which includes a rear heating portion, is changed at predetermined intervals depending on a desired recording linear velocity, so that a width of the top heating portion and a recording power thereof are changed.

Abstract: A storage apparatus uses a light beam to reproduce information from a recording medium having an information region with a recording format which includes a header including position information and a recording field including a data field for recording data. The storage apparatus is provided with a light source for emitting the light beam, and a control section for controlling a power L2 of the light beam in a vicinity of a start of the recording field to become higher than a power L3 at the data field of the recording field.