Abstract: In an optical disk system using a PRML identification system, a method for deriving an optimum recording wave in a short period of time is provided. Parameters of the recording wave are adjusted by using an evaluation value obtained by a signal evaluation method which is suitable for the PRML identification system as an index. In this case, as a parameter adjusting method, a plurality of adjusting methods are utilized.

Abstract: An information recording method enables the precise formation of a recording mark on a recording layer having a high light transmittance such as an L1 layer of a double-layered optical recording medium. The information recording method uses the following recording strategy. A laser beam is pulse-modulated so as to create a pulse series including a write pulse of a recording power and a cooling pulse of a base power. Data to be recorded is modulated to have a length of a recording mark along a track of the recording layer. At the same time, the length of the recording mark is made to correspond to an integral multiple nT of T where T is one clock cycle. An nT recording mark corresponding to nT is recorded by using the same number of write pulses and cooling pulses when n is 4 or larger. Moreover, an average width AveTc for a single cooling pulse width Tc is set to satisfy: 1.0<AveTc/T<1.6 and a total pulse width SumTc of the used cooling pulses is set to satisfy: 0.5?SumTc/nT?0.8.

Abstract: An optical disk recording method includes the steps of: providing a multi-pulse chain from a recording wave; independently changing the pulse rise timing and pulse fall timing (pulse width) of the first pulse in the multi-pulse chain in accordance with a preceding space length and a recording mark length; changing the pulse rise timing and pulse fall timing (pulse width) in accordance with a following space length and the recording mark length in a predetermined timing or in independence; and in relation to the smallest mark recorded by irradiation with mono pulse, changing the rise timing in accordance with the preceding space length and the recording mark length and the fall timing (pulse width) in accordance with the following space length and recording mark length, compensating various optical disks different in recording material without change of the fundamental waveform.

Abstract: A writing strategy parameters indexing method and a recording apparatus therefor. The writing strategy parameters indexing method includes operations of receiving an NRZ sequence; moving the NRZ sequence by as much as a bit with respect to a channel block using a slide-window having a length of N bits; determining whether a bit pattern of the NRZ sequence in the window-slide has a predetermined bit pattern; extracting writing strategy parameters corresponding to the predetermined bit pattern when the bit pattern of the NRZ sequence in the window-slide has the predetermined pattern; and generating recording pulses using the writing strategy parameters.

Abstract: A control signal generator of a light emitting device includes a driving unit to drive the light emitting device and a voltage divider to divide voltages, outputting a power control signal, wherein the power control signal is provided as an auxiliary power control signal to the driving unit so as to increase a number of power control signals to automatically provide automatic power control of the light emitting device.

Abstract: The present invention provides highly reliable PLL without influence of variations in amplitude of a reproduced signal or variations in inclination of an edge. An information-reproducing apparatus according to the present invention includes a unit for detecting a phase difference between a reproduced signal and a reproducing clock signal, a PLL circuit for regulating a frequency of the reproducing clock signal to compensate for the detected phase difference, a unit for detecting a state of the PLL circuit, and a unit for regulating a loop gain of the PLL circuit corresponding to the detected state.

Abstract: An optical disk recording method includes the steps of: providing a multi-pulse chain from a recording wave; independently changing the pulse rise timing and pulse fall timing (pulse width) of the first pulse in the multi-pulse chain in accordance with a preceding space length and a recording mark length; changing the pulse rise timing and pulse fall timing (pulse width) in accordance with a following space length and the recording mark length in a predetermined timing or in independence; and in relation to the smallest mark recorded by irradiation with mono pulse, changing the rise timing in accordance with the preceding space length and the recording mark length and the fall timing (pulse width) in accordance with the following space length and recording mark length, compensating various optical disks different in recording material without change of the fundamental waveform.

Abstract: A recording and reproducing method, wherein, on recording and reproduction of a recordable DVD medium, which has a recording layer containing an organic dye on a substrate having a guide groove with wobble, wherein linear velocity conditions for CLV recording is recorded on the substrate, recording starts at a linear velocity less than a highest linear velocity at the innermost circumference; when the linear velocity is switched over to the highest linear velocity on the way, a comparison is made between an optimum recording power of Po at the highest recording velocity that is temporarily optimized by test-writing in a power measurement area at the outermost circumference and an optimum recording power of Pi at the highest linear velocity that is recorded in the substrate; in the case of Po>Pi, a value given by the formula of “(Po+Pi)/2+(Po?Pi)2Pi” is employed as a recording power with which recording starts at the highest linear velocity; and in the case of Po?Pi, Pi is employed.

Abstract: An information recording technique for forming a recording mark with a multi-pulse sequence, which is increased by one pulse with an irradiation power Pw for every increase of 2T in a temporal length nT of the recording mark is provided. Particularly, this technique realizes a recording strategy that is simple in its configuration but is capable of improving the consistency of mark shapes in forming the recording marks when the value n of the temporal length nT is an odd number. More specifically, when n is an odd number and n?7, a period from the fall of a first pulse to the fall of a second pulse is set to 2.5 T and a period corresponding to a last pulse is set to (2+?1o)T where the value of ?1o is optimized within a range of 0<?1o?1. In this way, the multi-pulse sequence can be adjusted from the front pulse side and the rear pulse side so that an overall consistency can be realized in the mark shape upon recording the mark.

Abstract: It is an object of the present invention to provide a method for recording data in an optical recording medium which can form a recording mark having desired length and width in a write-once type optical recording medium. The method for recording data in an optical recording medium according to the present invention is constituted so as to project a laser beam whose power is modulated by a pulse train pattern onto an optical recording medium including a substrate, a first recording layer, a second recording layer and a light transmission layer 16 wherein a recording pulse of the pulse train pattern is divided into (n?1) divided pulses and the power of the laser beam is set to a recording power Pw at the peak of each of the divided pulses, set to a second bottom power Pb2 at a portion immediately after a last divided pulse and set to a first bottom power Pb1 at other intervals where Pb1 is higher than Pb2.

Abstract: In an optical recording method used when information is recorded in a phase-change recording layer of a large-capacity rewritable optical recording medium such as a DVD-RW, one block pulse is used as a recording pulse for forming one recording mark when a recording velocity is higher than a recording linear velocity at which the rewritable optical recording medium can be rewritten, whereas a pulse train comprised of a plurality of short pulses is used as the recording pulse for forming one recording pulse when the recording velocity is within recording linear velocities at which the rewritable optical recording medium can be rewritten, whereby high-velocity recording is realized.

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: A data recording method according to the present invention is a method for recording data as edge position information, including marks and spaces of multiple different lengths, on a storage medium by irradiating the storage medium with a pulsed energy beam. The method includes the steps of: (A) generating a write code sequence based on the data to be recorded; (B) determining a write pulse waveform, defining the power modulation of the energy beam, according to the code lengths of respective codes included in the write code sequence; and (C) modulating the power of the energy beam based on the write pulse waveform.

Abstract: A recording method and drive for optical storage media. The method inserts or replaces a special pattern in a recording EFM signal before the recording process is interrupted. Therefore, the special pattern is recorded either before or on the interrupted position. The starting position of the succeeding recording process is located by searching for the special pattern.

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

Abstract: 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: The objective of this invention is to provide a type of data processing device and a type of data recording/reproduction device that can restart data write processing correctly from an interruption position after data write processing on a recording medium is interrupted. When write is interrupted, prescribed information that indicates the tail of the data written before said interruption is obtained from the written data. When write is restarted, first, data read processing is started. From the read data, the tail of the write data before said interruption is determined based on said obtained information. Then, data write processing is restarted and connected to said determined tail of the write data. In write clock signal generating part (45), write clock signal CK3 locked to the phase of read clock signal CK2 is generated. Consequently, it is possible to suppress discontinuity in the connection of write in company with switching from read processing to write processing.

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

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

Abstract: It is an object of the present invention to provide an information recording method for recording information in a data rewritable type optical recording medium having a plurality of information recording layers, which can form recording marks having good shapes. In the information recording method according to the present invention, a plurality of recording marks selected from a group consisting of several types of recording marks with different lengths are formed in an optical recording medium 10 having at least a stacked L0 layer 20 and L1 layer 30 by projecting a laser beam via a light incidence plane. In the case of forming at least one recording mark among the several types of recording marks in L0 layer 20, the recording powers of a top pulse Ttop and a last pulse Tlp of the laser beam are set to Pw0? lower than the recording power Pw0 of a multi-pulse Tmp thereof.

Abstract: To form recording waveforms optimal to all optical discs including unknown discs and inferior quality discs. In an optical disc apparatus according to the present invention, a CPU changes a previously set pulse width at a predetermined code length by a predetermined value and controls an optical pickup, an RF amplifier, an evaluation index measurement circuit, and the like. With use of the changed pulse width, an asymmetry of a reproduction signal at the time of recording and reproducing test data on the optical disc is measured. On the basis of the measured asymmetry of the reproduction signal, a correction value for correcting the previously set pulse width at the predetermined code length is calculated. On the basis of the calculated correction value, the pulse width at the predetermined code length is corrected.

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

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

Abstract: The present invention relates to a method of writing data on a master substrate (10) for optical recording, the master substrate comprising a recording layer (12) and a substrate layer (14), and the recording layer comprising a phase-change material the phase of which can be transferred from crystalline to amorphous by projecting light on the recording 5 layer, the method comprising the steps of: writing a first amorphous mark (32) from a plurality of amorphous marks on the master substrate by at least one write pulse, and providing a cooling gap before the next amorphous mark (32) will be written.

Abstract: The object of the present invention is to provide an optical recording and reproducing method for a dye-based recordable optical recording medium includes recording shortest marks on an organic dye recording layer formed on a substrate having a guide groove with a wobble formed thereon using one pulse which is more highly energized than pulses of each of marks other than the shortest marks; recording each of the third shortest marks and still longer marks using one pulse beam of which the rear edge is energized for a given length of time, and the energized pulse power is equal to the pulse power of each of the second shortest marks, and irradiating cooling pulses onto the backwards of the respective pulse beams of all the marks during recording at an optical energy of 0.1 mW or less for a given length of time, and provide an apparatus for the same.

Abstract: A write-once high density optical recording medium capable of a high speed recording that effectively forms space between recording marks. A recording layer 18 of a high speed write-once optical recording medium 10 is formed by laminating a first sub recording layer 18A and a second sub recording layer 18B each containing a metal as its main component. When the recording layer (laminated recording layer) 18 is irradiated with a laser beam, the main component metals contained in the first and second sub recording layers 18A, 18B diffuse and are mixed together by means of the irradiation, thereby forming recording marks whose reflectance have been irreversibly changed due to such mixing. At this time, after an irradiation using a laser beam for forming recording marks, a power level P1 lower than a read power is maintained for a predetermined time Ti.

Abstract: A method of compensating for tilt and/or defocus and an apparatus therefor. The apparatus has a tilt and/or defocus detector detecting the tilt and/or defocus of an optical recording medium, and a recording compensator compensating a write pulse having a predetermined recording pattern using a predetermined system with respect to the detected tilt and/or defocus. The apparatus both adjusts write power with respect to the detected defocus, shifts the recording pattern with respect to the detected tilt, adjusts a power level and/or write time required for recording, and records a recording mark having a desired size (length and width). The apparatus is useful in compensating for tilt and/or defocus in a high-density optical system.

Abstract: A recording method is provided, which comprises the steps of (a) generating a plurality of pulse sequences corresponding to a plurality of linear velocities, (b) while rotating a recording medium with a linear velocity selected from the plurality of linear velocities, forming at least one of a recording mark and a space by irradiating the recording medium with a pulse sequence selected from the plurality of pulse sequences, the pulse corresponding to the linear velocity. The step (a) comprises the steps of (a-1) measuring at least one first recording parameter corresponding to at least one linear velocity selected from the plurality of linear velocities, (a-2) determining a second recording parameter corresponding to the plurality of linear velocities based on the at least one first recording parameter measured, and (a-3) generating the plurality of pulse sequences corresponding to the plurality of linear velocities based on the second recording parameter measured.

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: An optical recording method of recording information to a phase change optical recording medium with alternate application of peak power and bias power in a pulse manner and with changing a pulse application interval continuously from an inner part through an outer part of the recording medium with an interval proportional to a window width Tw and a fixed interval, comprising the step of starting a top peak power application interval with a delay from a data input pulse signal starting time for a target mark length nTw, where n denotes an integer in a range between 3 and 14, with changing the delay in proportion to the window width Tw with changing a proportionality factor discretely with respect each linear velocity.

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

Abstract: In a method of recording information by varying the front- and rear-edge positions of a mark by integer multiples of a specific interval, the recording density is increased without narrowing the intervals of edge position variation and without being influenced by the detection dynamic range. A data cell is divided at specific intervals ?, and the front- and rear-edge positions of the mark are disposed at any desired positions at specific intervals ?. Thus the mark length and the number of positions the mark can take can be increased, so that the recording density can be increased with the same margin as that of the prior art.

Abstract: An information recording method including irradiating an optical information recording medium containing a phase change recording layer on a substrate having a guide groove with continuous light of a laser beam having an erase power level Pe to determine a transition linear velocity Vo defined as a minimum linear velocity above which the following relationship is satisfied: Rr=Ra/Rb<1, wherein Rr represents a reflection light intensity ratio, and Ra and Rb represent a reflection light intensity measured after and before the irradiation of the optical information recording medium with the continuous light, respectively, prior to recording information in the optical information recording medium.

Abstract: In order that it is realized to put 16× speed DVD-RAM in practice, a recording method coping with CAV (constant angular velocity) and a method for improving S/N ratio are provided and an optical disk device using them is provided. In order that a cutoff phenomenon of pulse in a laser driving circuit may not occur, the shortest pulse width is set at 1 Tw or more where Tw indicates a window width, and a recording pulse in which a 4T mark is recorded with a mono pulse where T indicates a detection window width and the parameter setting range are prescribed. Simultaneously, a reproduction power for 6× speed or more is set at 1.5-2.0 mW, different from a conventional value, and a setup sequence with which deterioration of data in reproducing does not occur is provided. Thereby it becomes possible to put 16× speed DVD-RAM in practice.

Abstract: The information recording apparatus irradiates a laser beam on a recording medium such as an optical disk and forms a recording mark corresponding to a recording signal to record information. A recording pulse signal includes a mark period irradiating the laser beam for forming the recording mark and a space period in which the recording mark is not formed. The mark period has a top pulse period and an intermediate bias period following the top pulse period. The mark period constituted by the top pulse period and the intermediate bias period does not have a continuous part of a plurality of pulses having a small pulse width unlike a pulse train, so that the correct recording mark can be stably formed on the recording medium without an inadequate deformation of a recording pulse shape, even in the case of a high speed recording.

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

Abstract: A method for recording data in an optical recording medium which can record data in information recording layers other than an information recording layer farthest from a light incidence plane of an optical recording medium including a plurality of information recording layers in a desired manner and reproduce data from information recording layers other than the information recording layer farthest from the light incidence plane in a desired manner.

Abstract: An optical disc system includes a disc recording unit for recording an information signal on an optical disc by switching irradiation power of laser light to be applied to the optical disc in accordance with the information signal. The disc recording unit includes a semiconductor laser; a laser-power controlling circuit for outputting a laser-driving-current instruction signal; a recording-pulse generating circuit for outputting a laser-modulation timing pulse; a laser driving circuit for generating a laser driving current in accordance with the laser-driving-current instruction signal and the laser-modulation timing pulse; and a correction-data storage for storing as correction data the shift between the laser-modulation timing pulse and the pulse position of the laser driving current.

Abstract: In an optical record carrier recording method for forming marks and lands by irradiating a radiation beam onto a recording surface of an optical record carrier, the radiation beam for each mark to be recorded is set to at least one write power level (Pw) capable of forming a mark during a mark period (31) and, for each land between the marks, to at least one bottom power level (P0) incapable of forming a mark during a land period (32). When recording a wobble signal on the record carrier, in order to achieve a better wobble signal-to-noise ratio during writing, the bottom power level (P0) is temporarily raised to an intermediate power level (Pi) during an intermediate period (34). Preferably, the intermediate power level (Pi) is set within a range of from 1.5 to 6, in particular, from 2 to 4, times the bottom power level (P0).

Abstract: A recording method suitable for high-density recording is provided to increase the reproduction quality. An optical information recording method is for recording information on an optical recording medium by irradiation of a write pulse of a laser beam to perform reproduction in a production system using a PRML detection scheme. The method includes recording a recording mark by a single write pulse, when the total length of the recording mark to be recorded and a space adjacent to the recording mark is less than a diameter of an effective reproduction spot, being 0.82×(?/NA), where ? is a wavelength of a reproduction laser beam and NA is a numerical aperture.

Abstract: A recording method suitable for high-density recording is provided. When information is recorded on an optical recording medium with irradiation of a write pulse of a laser beam, a length corresponding to 7 T is set to be equal to or less than the spot diameter ?/NA of the laser beam where T is one recording clock cycle, ? is a wavelength of the laser beam, and NA is a numerical aperture of the objective lens, and a specified mark with a length corresponding to 3 T or more is recorded by a single write pulse.

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: The present invention provides CD-RW which makes high velocity recording at a level of at least 24-times velocity possible, rewritable DVD which makes high velocity recording at a level of at least 6-times velocity possible, and a recording method therefor, while maintaining interchangeability with conventional CD-RW standards and rewritable DVD standards. A rewritable optical recording medium comprising a substrate and a phase-change type recording layer, wherein a portion in a crystalline state corresponds to an unrecorded or erased state, and a portion in an amorphous state correspond to a recorded state, to record EFM modulated information by forming amorphous marks by irradiating the recording layer with a recording laser beam, and wherein recording is carried out by irradiating a recording laser beam having a wavelength of about 780 nm through an optical system having a numerical aperture NA of 0.5 or 0.

Abstract: Method for controlling a laser power used in recording on an optical disk includes: causing the laser to emit a test light emission pattern including a multipulse light emission interval and an at-bottom value continuous light emission interval; receiving the test light emission pattern of the laser to convert the pattern to an electric signal and to thereby obtain a light detection signal; calculating a detection value of a multipulse average value from the average value of the light detection signal, and calculating a bottom detection value from the light detection signal to obtain a light emission power characteristic of the laser on a supplied current based on the detection value of the multipulse average value and the bottom detection value; and controlling the current supplied to the laser based on the light emission power characteristic on the current supplied to the laser.

Abstract: Pulses modulated between the erase power and the bottom power are used instead of cooling pulses for an optical disk medium that needs a write strategy with 4-valued power levels. Consequently, pulse instruction lines for the cooling pulses, power level instruction lines, and corresponding current source within the laser driver can be omitted. Decrease in size and lower power consumption can be accomplished.

Abstract: An optimum performance is achieved relative to write-once type optical recording mediums on which information is recorded by means of a blue-violet semiconductor laser. An optical disc recording/reproduction apparatus 10 comprises an LD control section 17 adapted to control the irradiation power of a laser when writing data. If the cycle of the channel clock is T, when forming a recording mark having a length of n×T (n being an integer not smaller than 2), a pulse beam is irradiated onto the write-once type information recording medium for n/2 times (decimals, if any, being to be rounded down). When forming a recording mark having a length of not smaller than 6T and even number times of T, a pulse beam is irradiated for n/2 times with all the intermediate pulse beams synchronized with the phase of the channel clock except the leading pulse beam and the tail end pulse beam.

Abstract: A method of writing a mark to an optical disc includes receiving data to be written and generating a control signal for a laser pulse having a melt period that transitions to a growth period wherein the melt period is characterized by a melt power and the growth period is characterized by a growth power.

Abstract: It is an object of the present invention to provide an information recording method for recording information in a data rewritable type optical recording medium having a plurality of information recording layers, which can form recording marks having good shapes. In the information recording method according to the present invention, information is recorded in an optical recording medium 10 having at least a stacked L0 layer 20 and L1 layer 30 by projecting a laser beam whose power is modulated thereonto via a light incidence plane 13a. When information is recorded, ?/NA is set to be equal to or shorter than 700 nm, where ? is the wavelength of the laser beam and NA is the numerical aperture of an objective lens for converging the laser beam, and a pulse width Ttop0 of a top pulse of the laser beam when information is to be recorded in the L0 layer 20 is set to be shorter than a pulse width Ttop1 of a top pulse of the laser beam when information is to be recorded in the L1 layer 30.

Abstract: When a bias power level of a recording pulse waveform is varied entirely or partially, a shape of the recording pulse wave form is varied according to the variation. For example, when the bias power level is increased, a width or an edge position of a top pulse or a multi-pulse of the recording pulse waveform is varied correspondingly. Thereby, a total heat quantity of a recording laser light is not increased, and a preferable recording characteristic is maintained.

Abstract: The optical data recording method comprising the steps of: modulating data to be recorded, to generate a plurality of recording modulation codes; and emitting a pulse-like light beam to an optical disc, so that a plurality of recording marks and spaces which have lengths corresponding to the plurality of recording modulation codes are formed on the optical disc. In the optical data recording method, at least two of the plurality of recording marks comprises: a first pulse which is disposed at a front and forms a leading edge of the recording mark, a last pulse which is disposed at a backend and forms a trailing edge of the recording mark, and a multi-pulse train which is disposed between the first pulse and the last pulse and forms a center of the recording mark. The multi-pulse train has a pulse period longer than T which represents a reference period of the recording modulation code.