Abstract: A system includes a driver and a controller. The driver is configured to output a signal to a preamplifier of a heat source based on a thermal compensation value to cause the heat source to heat a spot on a storage medium. The controller is configured to adjust the thermal compensation value based on a duration for which the heat source is in an active or inactive operational state. The thermal compensation value is indicative of a history of durations that the heat source was in the active or inactive operational state.

Abstract: An apparatus comprises a write pole for writing data to a magnetic recording medium and a near-field transducer (NFT) optically coupled to a laser source and configured to produce a thermal spot on the medium. A laser driver applies laser operation power (Iop) to the laser source. A channel circuit generates symbols having a length of nT, where T is a channel clock rate and n is an integer. The laser driver applies Iop to the laser source and a write driver applies bi-directional write currents to the write pole to record the symbols at a location of the thermal spot on the medium, wherein a duration of applying Iop to the laser source by the laser driver is dependent on a length of the symbols and the effective thermal spot size.

Abstract: A mark corresponding to recording data is formed on an optical disk by: encoding the recording data in accordance with a modulation code and generating encoded data; classifying the encoded data by a combination of at least two of a mark length of a mark, a space length of a preceding space, the mark length of a preceding mark, and the space length of a succeeding space; setting a correction amount for adjusting the position of the start edge and the end edge of a recording pulse based on an evaluation index of a decoding result, which is a result of decoding a reproduction signal of the encoded data, for each of the classification; and generating the recording pulse corresponding to the encoded data by using the correction amount corresponding to the classification of the run length of the encoded data.

Abstract: A storage medium controller has been designed to maintain thermal stability of a heat source based on a history of heat source active/inactive durations so that a variation in spot size generated by the heat source is reduced during Heat Assisted Magnetic Recording (HAMR). The storage medium controller modulates power to the heat source based on these active/inactive durations. While the heat source is inactive, the storage medium controller increases a thermal compensation value and after the heat source is activated, the storage medium controller drives the heat source according to a current parameter proportional to the thermal compensation value. As the heat source continues being active, the storage medium controller decreases the thermal compensation value and proportional current parameter so that thermal stability of the heat source is maintained.

Abstract: A heat-assisted magnetic recording device includes a write pole positionable adjacent a magnetic recording medium and configured to write data to the medium. A near-field transducer is situated proximate the write pole and configured to produce a thermal spot on the medium. A channel circuit is configured to generate a sequence of symbols having a length of nT, where T is a channel clock rate and n is an integer over a predetermined range. A write driver is configured to apply bi-directional write currents to the write pole to record the sequence of symbols at a location of the thermal spot on the medium, wherein a duration of applying the write currents to the write pole by the write driver is dependent on a length of the sequence of symbols and the effective thermal spot size.

Abstract: An optical medium reproduction device includes: a detection unit configured to form detection signals of respective channels by dividing a cross-section of a beam returning from the optical medium into a plurality of regions and performing division into at least one channel corresponding to the region at an outer side in a radial direction, at least one channel corresponding to the region that is different in position in a tangential direction, and a channel corresponding to the other regions, and, in a case of forming the detection signals of the channels, form the detection signal of at least one of the channels by weighting and adding a signal in a predetermined region among the plurality of regions; a multi-input equalizer unit configured to include a plurality of equalizer units to which the respective detection signals of the plurality of channels are supplied, and configured to form an equalized signal on the basis of the detection signals of the plurality of channels; and a binarization unit configure

Abstract: An information recording and reproducing apparatus including: a reproducing unit which generates a digital signal from an analog signal; a recording compensation unit which generates an expectation signal from the digital signal, detects a signal difference between the digital signal and the expectation signal, and adjusts a recording condition for recording the information; and a recording unit configured to record the information based on the recording condition. First recording compensation is performed for adjusting the recording condition using first recording where lengths of a preceding space and a succeeding space of a first recording mark and lengths of a preceding space and a succeeding space of a second recording mark are not in intersymbol interference; and second recording compensation is performed for adjusting the recording condition for the first recording mark using second recording data for changing a length of the second recording mark.

Abstract: Disclosed is an optical disc with a first area to store data for playback and that is reflective or opaque to visible light, and a second area that is transparent to visible light and includes first and second concentric rings. In one embodiment, a method of printing information on the optical disc includes: printing an inverse first text pattern in the first ring during a first printing on a first side, where the first text pattern is formed in reverse as viewed from the first side; printing a second text pattern in the second ring during a second printing on the first side, where the second text pattern is correctly visible from the first side; and printing, during the second printing, a first solid pattern to overlay at least a portion of the first text pattern, where the first text pattern is correctly visible as viewed from a second side.

Abstract: The present application discloses an information device for performing optical information processes for a recording medium including a phase-change recording layer which becomes amorphous under irradiation with pulsed amorphization light that has prescribed amorphization energy Ew. The information device includes an irradiator configured to irradiate a prescribed region of the phase-change recording layer with pulsed light and an energy setting portion which sets crystallization energy Ee for the pulsed light to crystallize the prescribed region. The crystallization energy Ee per the pulsed light, which is set by the energy setting portion, is greater than the amorphization energy Ew per the pulsed amorphization light.

Abstract: A recording waveform is adjusted based on the fluctuation amount of the mark edge position, focused on that fluctuation of a mark edge position is increased in aged deterioration of a recording signal. Specifically, the recording waveform is adjusted such that a fluctuation amount becomes minimum or a threshold value or less. Then, information is recorded on the optical disc using the recording waveform. Further, provided is a recording medium or an information recording apparatus which stores parameters of the recording waveform.

Abstract: An information reproducing apparatus includes a photodetector (200A) divided by a dividing line parallel to a recording track scanning direction into a first light-receiving section (202, 203) that receives reflected light of a center section of a recording track and a second light-receiving section (201, 204) that receives reflected light of a portion adjacent, in a radial direction of an optical disc, with respect to the center section, a first adaptive equalization filter (107) that performs waveform equalization of an output signal from the first light-receiving section (202, 203), a second adaptive equalization filter (120) that performs waveform equalization of an output signal from the second light-receiving section (201, 204), and a data decoder (108) that decodes reproduction data based on an output waveform from the first adaptive equalization filter (107) and an output waveform from the second adaptive equalization filter (120).

Abstract: Provided is an optical disc apparatus and an optical disc recording method, in which it is decided whether or not an optical disc recording medium is one of DVD-RW and DVD+RW when data is recorded in the medium. If it is decided that the medium is one of DVD-RW and DVD+RW, maximum length information is read out from a storage portion. The maximum length information contains a previously set maximum data length of data recorded to the medium by an optical pick-up portion in one recording operation. Data to be recorded is split into split data having a data length of the maximum data length or smaller. Further, an electric power value of a base electric power for controlling the semiconductor laser element to emit a laser beam with a bottom power is reset every recording operation of the split data.

Abstract: Embodiments of optical disc drives are described that perform automatic forward sense calibration of write laser power using a sample and hold sampling strategy that is automatically determined based on an automatically selected write strategy. Embodiments of the described optical disc drive may be dynamically configured to support any optical disc media, any write mode, and any write strategy. The write strategies supported may include dynamically changing write speeds and/or write power levels across the respective optical media tracks. As the optical drive is automatically configured for a selected write media/write mode/write strategy, the sample and hold sampling delays used to control the sampling of a forward sense feedback signal are also automatically configured, thereby allowing each forward sense sampling point to be aligned with an area of the forward sense feedback signal that corresponds to a power level of interest and that avoids distortion in the feedback signal.

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: Provided is an optical recording medium, including a recording target track that is a track on which small record carriers are arranged and on which information recording is performed by modulating the small record carriers through light irradiation; and a wobbling track on which the small record carriers are arranged in a wobbling manner, wherein a single wobbling track is formed to run parallel to a set of a plurality of recording target tracks.

Abstract: A recording apparatus characterized in that comprising a firmware configured to execute the following operation: performing a recording operation onto a rewritable optical recording medium with a recording speed selected from one of a plurality of recording speeds for an one-time optical recording medium; wherein the recording layer of the rewritable optical recording medium comprises at least four elements from Ge, In, Sb, Te, and Sn, wherein the component proportion of Sb/Te is ranged from 3 to 8, and the thickness of the recording layer is ranged from 3 nm to 25 nm.

Abstract: A semiconductor device mounted in an optical disk apparatus controls writing and reading of data in and from an optical disk. The device performs first processing for adjusting a write strategy in such a manner that based on error information corresponding to a shift in the phase of a reproduction signal with respect to a channel clock signal for data reproduction, which is generated based on the reproduction signal read from the optical disk, the value of the error information related to a plurality of recording marks to be evaluated becomes minimum as a whole. The device also performs second processing for adjusting a write strategy in such a manner that the value of the error information related to a desired recording mark becomes small.

Abstract: In write power adjustment for an optical disc having a plurality of information storage layers, data of trial writing is varied by the influence of layers other than a target layer. It is difficult, therefore, to determine optimal write power. A modulation M[m] is obtained from a reproduction signal amplitude of a signal subjected to the trial writing performed with use of write powers Pw[m] (m being an integer) of a plurality of kinds. At least an optimum write power intercept Pint_opt is determined by fitting a relation between the Pw[m] and the M[m] by a modulation characteristic formula M=Masy×(1?(Pint?Pasy)/(Pw?Pasy)) having an asymptotic modulation Masy, a write power intercept Pint, and an asymptotic write power Pasy as parameters. Approximation accuracy by the fitting and/or quality of the trial writing signal are evaluated with use of at least the M[m], the modulation characteristic formula, and the Pint_opt.

Abstract: A recording apparatus, which records information in an optical recording medium, includes: a mode-lock laser unit including a saturable absorber section that applies a bias voltage, a gain section that feeds a gain current, a semiconductor laser that emits laser light used to record the information on the optical recording medium, and an external resonator; an optical modulation unit performing amplification modulation on the laser light emitted from the mode-lock laser unit; a reference signal generation unit generating a master clock signal and supplying a signal synchronized with the master clock signal to the gain section of the semiconductor laser; a recording signal generation unit generating a recoding signal based on the master clock signal; and a driving circuit generating a driving pulse used to drive the optical modulation unit based on the recording signal.

Abstract: Provided are a method of optical writing on a disc and a device adopting the method. The method of optical writing includes initially driving a laser diode (LD) at a preset reference value corresponding to a target output, detecting an actual output power by monitoring light output by the LD, and comparing the actual output power to the target output power. The method further includes compensating the reference value and writing data to the optical disc using the compensated reference value.

Abstract: A reproduction method for reproducing a rewritable and readable optical information storage medium in such a manner that an information recording layer is disclosed. The reproduction method comprising: reading setting information of reproduction laser power for each information recording layer of the rewritable and readable optical information storage medium, the setting information being stored in the rewritable and readable optical information storage medium; and setting, based on the setting information thus read, reproduction laser power for the information recording layer that is closest to a reproduction-laser-incident surface to be not less than 1.0 mW but less than 1.1 mW.

Abstract: A driver circuit configured to generate a drive signal for an optical source comprises an overshoot controller that provides an amount of overshoot for a given logic state of the drive signal as a function of a duration of at least one previous logic state of the drive signal. The drive signal may alternate between a first logic state associated with a first operating mode of the optical source and a second logic state associated with a second operating mode of the optical source. The overshoot controller may be configured to provide amounts of overshoot for respective instances of the first logic state that are proportional to the durations of their respective immediately preceding second logic states. The driver circuit may be implemented in a heat-assisted magnetic recording system in which the optical source alternates between on and off states associated with respective magnetic write and magnetic read modes.

Abstract: Recording mark forming method utilizing a device including a laser and a laser drive carried by a pickup having a movement drive wherein a control controls the drives to irradiate a recording medium with laser pulse sequences to form recording marks having recording mark lengths between a predetermined and maximum lengths, a top section, a last section including a cooling period, and an intermediate period. Heat of mark front edges is controlled by top section recording parameters classified according to recording mark lengths and recording parameters of first through maximum recording mark lengths are classified into a same group. Heat of mark rear edges is controlled by cooling start positions for cooling periods classified according to recording mark lengths. Cooling start positions for a second predetermined mark length through the maximum mark length are classified into a same group. The second mark length is longer than the first mark length.

Abstract: Circuitry for controlling mode selection of a CD/DVD reader is described. In one embodiment, the CD/DVD reader has a first device having at least one analog output, a second device having at least one digital input and at least one analog input, and an interface circuit coupling the analog output of the first device to the digital input and the analog input in the second device. The interface circuit includes a circuitry to use a single control signal from the analog output of the first device to control the digital input and the analog input in the second device. Other embodiments are also described.

Abstract: A master strategy adjustment method includes performing first recording on a master with a predetermined strategy, performing first measurement of an evaluation value of the master of the first recording, forming a first optical disc based on the master after the first recording, performing second measurement of an evaluation value of the optical disc formed as the first optical disc, calculating a target value of the evaluation value of the master based on a difference with the first measurement evaluation value and the second measurement evaluation value, and adjusting the strategy so that the evaluation value with regard to the master matches the target value, performing recording on the master with the adjusted writing strategy, performing measurement of the evaluation value of the master, and performing determination of whether the evaluation value is within a predetermined range with the target value as a reference until an affirmative result is obtained.

Abstract: An optical information recording medium includes a recording layer in which a track is formed, the track having recording marks linearly arranged thereon. Each recording mark has a dimension corresponding to a reference mark length, which serves as a reference, in a track direction along which the track extends, the dimension being smaller than dimensions of the recording mark in two directions perpendicular to the track direction.

Abstract: Provided is an optical disk recording device including: a recording pulse information generation unit that generates, from a recording signal, recording pulse information corresponding to a power level of laser light; a recording code generation unit that generates a recording code by encoding the recording pulse information; and a decoded code generation unit that decodes the recording code. The recording code generation unit generates the recording code based on a cyclic cede representing each transmission of the power level by using a Gray code. The decoded code generation unit decodes the recording code by using a recording code corresponding to a power level at a predetermined timing and a recording code corresponding to a power level immediately prior to the power level at the predetermined timing.

Abstract: A method for recording information in form of a hologram. The method can generate a displacement signal by detecting a displacement of a holographic recording medium. The method can perform an exposure control operation that, if the sampling value of the displacement signal falls within an allowable displacement range, records the information item in the holographic recording medium, and if the sampling value of the displacement signal falls outside the allowable displacement range, blocks or reduces at least one of the information light and the reference light to a light intensity with which the information item is not recorded in the holographic recording medium.

Abstract: According to an embodiment, a storage medium includes a transparent resin substrate having a concentric or spiral groove and a recording film formed on the groove on the transparent resin substrate, a recording mark being formed by irradiation of a laser beam, wherein a reproduction durability count in a case where reproduction is continuously carried out by a laser beam is 1,000,000 or more.

Abstract: An optical information reproducing apparatus includes: an irradiation section irradiating a light beam onto an optical information recording medium, in which holes are formed along a virtual track on a recording medium, along the virtual track; a light receiving section receiving a reflected light beam when the light beam is reflected by the optical information recording medium and sequentially generating a light receiving signal corresponding to the light intensity; a detection section detecting a variation pattern appearing when a signal level of the light receiving signal changes according to the hole; and a code string generating section, when generating a code string corresponding to the signal level, generating a code corresponding to the one hole from the variation pattern if the variation pattern falls within a range and generating a code string, which includes a plurality of codes, from the variation pattern if the variation pattern exceeds the range.

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 medium and apparatus enable the number of data units of recording pulse information to be reduced. The recording medium includes an information area for recording set values of a recording pulse for forming recording marks. The set values include preceding space-based set values having a first reference value as a set value of a recording pulse corresponding to a predetermined preceding space and a first difference set value of a recording pulse corresponding to a space other than the predetermined preceding space; and trailing space-based set values having a second reference value as a set value of a recording pulse corresponding to a predetermined trailing space and a second difference set value of a recording pulse corresponding to a space other than the predetermined trailing space and which is expressed as a difference from the second reference value.

Abstract: A controller for a laser driver includes a parameter generation module, a timing encoding module, and a pulse generation module. The parameter generation module is configured to, for each mark contained in a bit stream, generate a set of timing parameters based on defining characteristics of the bit stream. The defining characteristics include length of the mark and at least one of (i) a length of a leading space prior to the mark and (ii) a length of a following space subsequent to the mark. The timing encoding module is configured to determine a plurality of pulse defining parameters based on the set of timing parameters. The pulse generation module is configured to create a plurality of pulses based on the plurality of pulse defining parameters, combine the plurality of pulses into a plurality of enable signals, and output the plurality of enable signals to the laser driver.

Abstract: A recording parameter setting device setting parameters of pulse sequences forming recording marks on recording media. The device includes a storage section storing first and second look-up tables, and a recording parameter setting section for obtaining from the tables and setting parameters corresponding to recording information. The pulse sequences form at least marks equal to or longer than a first predetermined length but not longer than a maximum mark length, and include top and last sections. Also, the first lookup table stores parameters for top sections that control heat of front edges of marks classified into a same group. The second lookup table stores parameters for last sections for controlling heat of rear edges that are equal to or longer than a second predetermined recording mark length, that is longer than the first predetermined recording mark length, through the maximum recording mark length and classified into a same group.

Abstract: In write power adjustment for an optical disc having a plurality of information storage layers, data of trial writing is varied by the influence of layers other than a target layer. It is difficult, therefore, to determine optimal write power. A modulation M[m] is obtained from a reproduction signal amplitude of a signal subjected to the trial writing performed with use of write powers Pw[m] (m being an integer) of a plurality of kinds. At least an optimum write power intercept Pint_opt is determined by fitting a relation between the Pw[m] and the M[m] by a modulation characteristic formula M=Masy×(1?(Pint?Pasy)/(Pw?Pasy)) having an asymptotic modulation Masy, a write power intercept Pint, and an asymptotic write power Pasy as parameters. Approximation accuracy by the fitting and/or quality of the trial writing signal are evaluated with use of at least the M[m], the modulation characteristic formula, and the Pint_opt.

Abstract: The invention prevents mark distortion during high-speed recording on an optical disc, thereby improving recording performance. A write pulse signal includes mark periods during which marks 201 are formed and space periods during which no marks are formed. Particular mark periods include a top pulse 101 having first write power Pw; a bias pulse 102 that follows the top pulse 101 and has bias power Pm lower than the first write power Pw; and a last pulse 103 that follows the bias pulse 102 and has second write power Pl lower than the first write power Pw.

Abstract: A recording method includes: generating a laser driving pulse, of which the number depends on a length of a mark which is formed, and where a pulse level of a pulse column at least in an intermediate pulse besides the lead pulse and the last pulse is sequentially decreased; performing laser emission, based on the laser driving pulse; and performing mark formation using thermal recording by laser irradiation on a recording medium.

Abstract: A controller of an optical storage apparatus for generating a plurality of control signals is provided. The controller includes a code generator implemented for determining a plurality of control codes according to an input data associated with data recording, and generating the control signals to deliver the control codes. Each of the control codes represents one power level. Besides, regarding each of the control signals, a minimum transmission pulse length thereof corresponds to more than one power symbol period.

Abstract: Aspects of the disclosure can provide a method to optimize optical recording. The method can include recording a pre-defined pattern on an optical medium according to a first write strategy, measuring edge timings corresponding to the pre-defined pattern recorded on the optical medium, determining a second write strategy including at least timing modifications to the first write strategy, and recording data on the optical medium according to the second write strategy. The timing modifications can be determined based on the measured edge timings, edge timing targets for desired edge timings and edge timing sensitivities to the timing modifications.

Abstract: A method for 3D recording of data on a medium formed from a transparent photosensitive material including at least one dopant. The method includes a first step of calibrating and checking a pulsed light source including calibrating the number of pulses, the level of fluence of each pulse emitted and the rate of the pulses and a step of inscribing an area of the material. The fluence of each pulse emitted, the number of pulses and the rate of the pulses are suitable for irradiating the material in the area so as to form fluorescent clusters stabilized from the dopant while minimizing the modification of the refractive index and the absorption coefficient of the medium in a wavelength range from visible to near infrared.

Abstract: An information recording medium includes a track on which a data sequence is recordable, and at least one of a PIC area in which a recording condition for recording the data sequence on the track is recorded. The recording condition includes a parameter for adjusting a position of a trailing end of a cooling pulse in a recording pulse waveform for forming the recording mark. The parameter is classified using a combination of a length of the recording mark, a length of a first space located adjacently previous to the recording mark and a length of a second space located adjacently subsequent to the recording mark. A recording apparatus is provided for recording a data sequence on an information recording medium based on the recording condition recorded on the information recording medium. An evaluation apparatus is provided for evaluating an information recording medium having the recording parameter recorded thereon.

Abstract: An optical recording medium including a plurality of recording layers to record/reproduce information using light with a predetermined wavelength, the information being recorded on one of the recording layers using a mark and a space, wherein a channel clock period T is provided for recording the mark on one of the recording layers. A plurality of pulses, including a last pulse arranged at an end of the pulses, are used to record the mark with length 3T, the mark being recorded with a condition that a width of the last pulse is minimum OT and maximum 1.10T, in which a first subsequent level lower than a peak power level of the last pulse is arranged next to the last pulse, and a second subsequent level lower than the peak power level but higher than the first subsequent level is arranged next to the first subsequent level.

Abstract: In an optical information storage medium reproduction apparatus (10) for reproducing an optical information storage medium including a plurality of information recording layers each including a recording mark having a length shorter than an optical system resolution limit, reproduction laser power for reading an information recording layer closest to a reproduction-laser-incident surface of the optical information storage medium is set to be lower than reproduction laser power for reading an information recording layer farthest from the reproduction-laser-incident surface but not lower than minimum reproduction laser power that satisfies a reproduction signal characteristic that the optical information storage medium reproduction apparatus (10) requires.

Abstract: An optical recording medium including a plurality of recording layers to record/reproduce information using light with a predetermined wavelength, the information being recorded on one of the recording layers using a mark and a space, wherein a channel clock period T is provided for recording the mark on one of the recording layers. A plurality of pulses, including a last pulse arranged at an end of the pulses, are used to record the mark with length 3T, the mark being recorded with a condition that a width of the last pulse is minimum 0T and maximum 1.10T, in which a first subsequent level lower than a peak power level of the last pulse is arranged next to the last pulse, and a second subsequent level lower than the peak power level but higher than the first subsequent level is arranged next to the first subsequent level.

Abstract: In an optical information storage medium reproduction apparatus (10) for reproducing an optical information storage medium including a plurality of information recording layers each including a recording mark having a length shorter than an optical system resolution limit, reproduction laser power for reading an information recording layer closest to a reproduction-laser-incident surface of the optical information storage medium is set to be lower than reproduction laser power for reading an information recording layer farthest from the reproduction-laser-incident surface but not lower than minimum reproduction laser power that satisfies a reproduction signal characteristic that the optical information storage medium reproduction apparatus (10) requires.

Abstract: Provided is an optical write device and method. The optical recording method includes generating a first signal including a preset write pulse power Pm in response to information to be written, generating a second signal including an over drive pulse power Po that is synchronized with the preset write pulse power Pm and which is at a higher level than the preset write pulse power Pm, and writing the information to an optical disc using a driving signal that is obtained by synthesizing the first and second signals.

Abstract: A method of and apparatus for recording data on an optical recording medium form a mark or a space by using a recording waveform having an erase pattern containing a multi-pulse. The method and the apparatus prevent distortion of the mark or the space and improve a mark shape such that a recording/reproducing characteristic of the optical recording medium is improved.

Abstract: In an optical information storage medium reproduction apparatus (10) for reproducing an optical information storage medium including a plurality of information recording layers each including a recording mark having a length shorter than an optical system resolution limit, reproduction laser power for reading an information recording layer closest to a reproduction-laser-incident surface of the optical information storage medium is set to be lower than reproduction laser power for reading an information recording layer farthest from the reproduction-laser-incident surface but not lower than minimum reproduction laser power that satisfies a reproduction signal characteristic that the optical information storage medium reproduction apparatus (10) requires.

Abstract: Provided is a mark forming apparatus including a head unit that forms a mark on a recording medium through laser beam irradiation based on a laser driving pulse, a control signal generation unit that generates a control signal at a start timing of the laser driving pulse supplied to the head unit, a multiplier that multiples a synchronization reference signal used to synchronize with the process of forming the mark on the recording medium in the head unit to generate a multiple signal, and a laser driving pulse generation unit that generates the laser driving pulse by setting the start timing of the laser driving pulse at resolution based on the multiple signal in accordance with the control signal.

Abstract: An optical recording method for recording mark length-modulated information on a recording medium by using a plurality of recording mark lengths. The optical recording method comprises the steps of: when a time length of one recording mark is denoted nT (T is a reference clock period equal to or less than 25 ns, and n is a natural number equal to or more than 2), (i) dividing the time length of the recording mark nT into ?1T, ?1T, ?1T, ?2T, ?2T, . . . , ?iT, ?iT, . . .