Abstract: This disclosure is related to systems, devices, processes, and methods to optimize a laser power boost amplitude, a laser power boost duration, or both in a heat-assisted data recording device, such as in heat-assisted magnetic recording (HAMR). The amplitude and duration for the laser power boost may be determined for a specific portion of a write operation, such as a first sector of the write operation. During operation of a data storage device, the laser power boost may provide additional power to the laser for the specific portion. Once the laser power boost duration has elapsed, the data storage device may continue providing power to the laser at the normal power input range of the laser. The laser power boost settings may be determined on a per head per zone basis, per track basis, or another configuration.

Abstract: A recording head includes a near-field transducer configured to heat one or more portions of a magnetic storage layer to generate a thermal profile in the magnetic storage layer. The recording head includes a write pole configured to generate a magnetization pattern, in the magnetic storage layer, that overlaps with the thermal profile in the magnetic storage layer. The write pole includes a non-uniform surface that faces the magnetic storage layer, the non-uniform surface configured to cause a portion of the magnetization pattern to be approximately linear.

Abstract: A method comprises performing a write operation using a heat-assisted magnetic recording (HAMR) drive operating at a plurality of temperatures. The method involves measuring a metric of write performance subsequent to the write operation at each of the operating temperatures. The method also involves detecting one or more laser mode hops using the metrics, and determining a temperature at which each of the detected mode hops occurred. The method further involves storing the temperature for each detected mode hop in a non-volatile memory of the drive. The method may involve mitigating laser mode hopping, such as by the drive avoiding the stored temperature(s).

Abstract: A circuit may be configured to reduce the power consumption and extend the life of a near field transducer of a heat-assisted magnetic recording (HAMR) device by pulsing a laser. The current that drives the laser may be of a frequency and magnitude so as to approximate the value of a continuous current in a continuous, non-pulsed laser. A system on chip (SOC), which may include a HAMR channel, can generate a laser data signal that may be synchronous with, and offset from, a write signal by a certain period of time, and may calculate certain parameters such as peak current and pulse width that may be applied to the signals in a preamp. The preamp signals can be used to program data to a disc medium.

Abstract: A method for evaluating a reproduction performance which reproduces a specific pattern recording signal to measure a reproduced signal noise, and calculates an evaluated value of a reproduction performance on the basis of a frequency characteristic of the measured reproduced signal noise.

Abstract: A writing method for an optical disk drive includes receiving a command to write a disc; implementing an optimum power control (OPC) test for a predetermined data transfer rate to obtain a relation of a beta parameter to writing power; acquiring a writing power for the predetermined data transfer rate with a target beta parameter; calculating the energy area ratio of writing strategies for every data transfer rate; multiplying the energy area ratio by the writing power for the predetermined data transfer rate to produce the writing power for every data transfer rate; and compensating the writing power with automatic writing control.

Abstract: A recording power determination method for determining a recording power of an optical beam for recording data on an information storage medium includes the steps of recording test data on the information storage medium at a plurality of test recording powers; reading the test data recorded at each test recording power, generating a signal, and measuring a modulation factor of the signal corresponding to each test recording power; calculating a product of an n'th power of each test recording power and the corresponding modulation factor, thereby obtaining a plurality of products corresponding to the plurality of test recording powers, where n is a value of exponent and is a real number other than 1; calculating a first recording power based on the correlation between the plurality of test recording powers and the plurality of products; and calculating the recording power based on the first recording power.

Abstract: In an optical disk recording apparatus, a monitor monitors a recording power of a laser light. A laser control circuit enables a laser diode to perform test recording while using the monitor to monitor the recording power of the laser light and while controlling a laser drive voltage, so that the monitored recording power reaches a given reference value during the test recording. A voltage measurement section measures the laser drive voltage when the recording power of the laser light reaches the reference value. A calculation section calculates an initial laser drive voltage from the reference value of the recording power and the measured laser drive voltage corresponding to the reference value. A main controller allows the laser control circuit to set the calculated initial laser drive voltage and to start the recording while supplying the laser control circuit with the target value so that an actual recording power of the laser light promptly reaches the target value during the course of the recording.

Abstract: When a super resolution technology for optical disks is used in a situation where optical disk management information is formed with a signal that cannot be reproduced by a reproduction method based on a conventional optical disk technology, optical disk drives cannot make recording adjustments and/or reproduction adjustments. An optical disk drive uses an optical disk that forms a management information signal with pits not smaller in size than optical resolution and can be read by a reproduction method based on a conventional optical disk technology. When the optical disk drive records information onto or reproduces information from the optical disk having the super resolution region, it is possible to make proper recording adjustments or reproduction adjustments and perform a proper recording operation or reproducing operation in an optical disk's information region for user information recording or reproduction.

Abstract: Apparatus and method for light source power control during the writing of data to a storage medium. In accordance with various embodiments, a data recording head is provided having a magnetic transducer and a light source. The light source is driven at a first power level to irradiate an adjacent storage medium prior to the writing if data to the medium using the magnetic transducer. The first power level is insufficient to alter a magnetization state of the medium. The light source is subsequently transitioned to a higher, second power level to irradiate the storage medium during the writing of data to said medium using the magnetic transducer, the second power level being sufficient to alter said magnetization state of the medium.

Abstract: When recording is carried out in a DVD-RAM, if at least one address mark could have been detected at the header section, after a test light emission for a laser power control is carried out at a GAP section, normal recording is carried out from GUARD1. Herein, if the delay time in the reproduced data would have increased, and if the head of the GAP section has been passed by at the timing when the AM4 is detected in a period during judging whether the fourth AM has been detected or not, it would not be possible to carry out a test light emission normally at the GAP section. In an optical disc recording device of the present invention, when any of the first to third address marks could have been detected, a test light emission is carried out at the GAP section as conventional, and normal recording is carried out from GUARD1 with controlling the laser powers on the basis of that result.

Abstract: A method of compensating for output variations in laser power output over time in a system using a laser to record visible marks on an optical disc, the method comprising (a) applying a test light beam from the laser to the optical disc to determine a test value of an optical parameter, (b) determining a difference between the test value and a predetermined reference value for the optical parameter, and (c) adjusting the laser power output to compensate for the difference.

Abstract: Various systems, methods, and programs embodied on a computer-readable medium are provided for calibrating a laser power in an optical disc drive. In one embodiment, a range of reflectivity of an optical disc in the optical disc drive is established. A calibration pattern of marked segments is written to the optical disc and the reflectivity of the marked segments is measured. An average reflectivity is generated for each one of a plurality of laser power settings within the range of reflectivity, thereby obtaining a curve that depicts the average reflectivity with respect to the laser power settings. The laser power setting at a knee of the curve is identified and a slope of the curve at a position on the curve where the average reflectivity decreases as the laser power settings increase is determined. The laser power setting is calculated that results in a predefined darkness based upon the laser power setting at the knee and based upon the slope.

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

Abstract: Information recording equipment of the present invention includes a multiplexer to generate n pieces of synchronous high-speed pulses. Instead of a normal m:1 multiplexer configuration for parallel-serial conversion, an m:n multiplexer configuration is used which generates m pieces of output signals from n pieces of input signals. The recording equipment including the m:n multiplexer enables high-resolution and high-speed pulse generation and carries out multipulse and multilevel signal generation.

Abstract: Prior to a main record, a trial write of data in an optical disc is performed in accordance with the characteristics between a record velocity and an optimum record power (Steps S2 to S4). The quality of a signal reproduced from the trial-written data is measured (Step S5). It is judged from the measured quality of the reproduced signal whether the predetermined velocity is a recordable velocity satisfying the characteristics between the record velocity and the optimum record power (Step 5). The main record is executed in accordance with the judgment result.

Abstract: If data is recorded using a disc with deviating characteristics and a recorder with deviating characteristics, data will not be appropriately recorded, and errors will occur in the read signal. Standard recording pulse parameters specifying recording pulse positions for plural possible mark length and space length combinations are read from a writable optical disc, these standard recording pulse parameters are then used for test writing, the standard recording pulse parameters are changed uniformly or individually, a best recording pulse parameter is thus obtained, and jitter can be reduced.

Abstract: The present invention provides a magneto-optical recording method capable of securing a sufficient phase margin, even if a recording power or medium temperature fluctuates, and obtaining a reproduction signal having a preferable quality, wherein the time phases of a laser pulse and a modulation magnetic field are set to a time phase of maximizing in which a recording power margin.

Abstract: A power calibration apparatus identifies a calibration area divided by an EFM frame unit on an optical disc and controls writing by a writing means. According to read out information for test writing written in the optical disc, a first writing power is calculated. By setting the first recording power as an initial value and changing the first recording power by a dense degree through steps corresponding to the number of the calibration areas divided by the EFM frame unit, the apparatus urges writing by the writing means. According to the read out information for the test writing written in the optical disc, a second writing power is calculated.

Abstract: An optical disk is made of tracks that are magnetically separated from one another by scanning a focused light beam over lands between tracks at a predetermined power and annealing to lower the magnetic anisotropy of a magnetic layer on the lands, and is provided with a power testing region comprising one or more tracks for finding the predetermined annealing power at the location of at least one of the group consisting of a specific region within the data region, a region more to the inner side than the innermost track of the data region, and a region more to the outer side than the outermost track of the data region. Thus, an optical disk and a manufacturing method for the same can be provided that have a high recording density and with which annealing can be implemented in a short time and at the correct annealing width.

Abstract: A system and method are disclosed for recording information on a phase change medium is disclosed. The method includes irradiating a region of the phase change medium with a first dose of laser energy. A first portion of the region is irradiated with a second dose of laser energy in a manner that causes the first portion of the region irradiated with the second dose of laser energy to be in a different state than a second portion of the region that is not irradiated by the second dose of laser energy.

Abstract: It is an object of the present invention to provide an inspection method for judging whether or not a phase change type medium can be used as a write-once type medium.

Abstract: A storage unit having functions of controlling a write power, a read power and a reproducing magnetic field with respect to an optical recording medium, is provided with a first section for storing test write data on the optical recording medium for each write temperature information during a write, and a second section for controlling at least the reproducing magnetic field depending on optimum reproducing conditions which are obtained by reproducing the test write data corresponding to a write temperature of data which is to be actually reproduced from the optical recording medium during a read.

Abstract: A magneto-optical recording/reproducing method is disclosed which causes a laser beam to be emitted to a disc recording medium having information recorded thereon earlier by magnetic field modulation, the laser beam causing the disc recording medium to develop a temperature distribution such as to generate a driving force for moving a domain wall of a magnetic domain in the medium so that the magnetic domain smaller in diameter than a spot of the laser beam is expanded sufficiently to let information recorded in the domain be detected. The method comprises the steps of: recording information to the disc recording medium while rotating the medium in a first rotating direction; and reproducing the information that was recorded to the disc recording medium in the recording step while rotating the medium in a second rotating direction reverse to the first rotating direction.

Abstract: A reproducing apparatus reproduces a signal recorded in a magneto-optical disk. The magneto-optical disk includes a layered structure having a recording layer, an intermediate layer and a reproducing layer. Laser light is illuminated from an optical head to the magneto-optical disk in such an intensity that no magnetic domain is transferred from the recording layer to the reproducing layer only by the laser light. In this state, alternating magnetic field is applied through a magnetic head to the magneto-optical disk, thereby concurrently causing transfer and expansion of a magnetic domain to the reproducing layer. As a result, transfer of the magnetic domain is effected with expansion.

Abstract: The present invention provides a magneto-optical recording method capable of securing a sufficient phase margin, even if a recording power or medium temperature fluctuates, and obtaining a reproduction signal having a preferable quality, wherein the time phases of a laser pulse and a modulation magnetic field are set to a time phase of maximizing in which a recording power margin.

Abstract: External magnetic fields H(x) or reproducing light beams L(x) having different intensity patterns are applied to an identical recording position on a magneto-optical recording medium so that different pieces of information corresponding to the patterns are reproduced from the identical recording position. A function H(x) or L(x) is a password for obtaining the information. Only a person, who knows the function, can access specified information recorded on the magneto-optical recording medium. The function H(x) or L(x) is a function in which the magnetic field intensity or the light intensity is modulated with respect to the recording position x so that magnetic domains may be thinned out to perform reproduction at a specified cycle from continuous magnetic domains in a recording area.

Abstract: A reproducing laser output can be adjusted to an optimal level. To this end, a magneto-optical disk device includes a differential amplifier and a shortest recording mark identifier that detects a shortest recording mark reproducing signal corresponding to a component of a shortest recording mark in a reproducing signal obtained by reproducing a magneto-optical disk. In addition, an envelope detector detects an amplitude level of the shortest recording mark reproducing signal, a comparator compares the amplitude level with a reference voltage outputted from the reference voltage source, and a drive control section adjusts the reproducing laser beam to an output level at which the amplitude level is equal to or higher than the reference voltage, based on a comparison result from the comparator.

Abstract: A high-speed large capacity file system is built in which the track density is improved by applying a highly precise magnetic domain width control technique to a light pulse-irradiated magnetic field modulation magnetooptical disk device which can be overwritten and is suitable for the improvement of the bit density. For the purpose, bipolar magnetic domains having edges of positive and negative polarities with respect to the direction of movement of a light spot are formed and the recording condition is optimized. Normal recording is carried out on the basis of the result of the optimization of the recording condition.

Abstract: The present invention provides a magnetic signal reproducing device including heating means for locally heating a reproducing region of a magnetic recording medium, first reproducing means for reading magnetic information in the reproducing region in a first temperature state to obtain a first reproduced signal, second reproducing means for reading magnetic information in almost the same region as the reproducing region in a second temperature state which is different from the first temperature state to obtain a second reproduced signal, and correcting means for correcting the first reproduced signal based on the second reproduced signal to obtain an information reproducing signal representing information recorded in the reproducing region. According to this, even if a medium temperature in a non-heated region of the magnetic recording medium is shifted from a magnetization compensation point, a signal from the region is prevented from mixing into a reproducing signal.

Abstract: An optical disk is made of tracks that are magnetically separated from one another by scanning a focused light beam over lands between tracks at a predetermined power and annealing to lower the magnetic anisotropy of a magnetic layer on the lands, and is provided with a power testing region comprising one or more tracks for finding the predetermined annealing power at the location of at least one of the group consisting of a specific region within the data region, a region more to the inner side than the innermost track of the data region, and a region more to the outer side than the outermost track of the data region. Thus, an optical disk and a manufacturing method for the same can be provided that have a high recording density and with which annealing can be implemented in a short time and at the correct annealing width.

Abstract: In an information storage apparatus for recording information in a recording medium by applying an external magnetic field to a position illuminated by the light beam, an external magnetic field control part controls an external magnetic field strength based on the illuminated position on the recording medium.

Abstract: A high-speed large capacity file system is built in which the track density is improved by applying a highly precise magnetic domain width control technique to a light pulse-irradiated magnetic field modulation magnetooptical disk device which can be overwritten and is suitable for the improvement of the bit density. For the purpose, bipolar magnetic domains having edges of positive and negative polarities with respect to the direction of movement of a light spot are formed and the recording condition is optimized. Normal recording is carried out on the basis of the result of the optimization of the recording condition.

Abstract: A high-speed large capacity file system is built in which the track density is improved by applying a highly precise magnetic domain width control technique to a light pulse-irradiated magnetic field modulation magnetooptical disk device which can be overwritten and is suitable for the improvement of the bit density. For the purpose, bipolar magnetic domains having edges of positive and negative polarities with respect to the direction of movement of a light spot are formed and the recording condition is optimized. Normal recording is carried out on the basis of the result of the optimization of the recording condition.