WO1993010527A1 - Appareil a disque magneto-optique et support d'enregistrement - Google Patents

Appareil a disque magneto-optique et support d'enregistrement Download PDF

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Publication number
WO1993010527A1
WO1993010527A1 PCT/JP1992/001460 JP9201460W WO9310527A1 WO 1993010527 A1 WO1993010527 A1 WO 1993010527A1 JP 9201460 W JP9201460 W JP 9201460W WO 9310527 A1 WO9310527 A1 WO 9310527A1
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WO
WIPO (PCT)
Prior art keywords
recording
pulse
optical
signal
mark
Prior art date
Application number
PCT/JP1992/001460
Other languages
English (en)
Japanese (ja)
Inventor
Tsuyoshi Toda
Kazuo Shigematsu
Seiichi Mita
Toshimitsu Kaku
Takeshi Maeda
Fumiyoshi Kirino
Hiroshi Ide
Atsushi Saito
Original Assignee
Hitachi, Ltd.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from JP3294145A external-priority patent/JP3063314B2/ja
Priority claimed from JP4100897A external-priority patent/JPH05298737A/ja
Application filed by Hitachi, Ltd. filed Critical Hitachi, Ltd.
Priority to DE4293957T priority Critical patent/DE4293957T1/de
Priority to US08/087,777 priority patent/US5642343A/en
Priority to DE4293957A priority patent/DE4293957C2/de
Publication of WO1993010527A1 publication Critical patent/WO1993010527A1/fr

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Classifications

    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
    • G11B7/12—Heads, e.g. forming of the optical beam spot or modulation of the optical beam
    • G11B7/125—Optical beam sources therefor, e.g. laser control circuitry specially adapted for optical storage devices; Modulators, e.g. means for controlling the size or intensity of optical spots or optical traces
    • G11B7/126—Circuits, methods or arrangements for laser control or stabilisation
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B11/00—Recording on or reproducing from the same record carrier wherein for these two operations the methods are covered by different main groups of groups G11B3/00 - G11B7/00 or by different subgroups of group G11B9/00; Record carriers therefor
    • G11B11/10—Recording on or reproducing from the same record carrier wherein for these two operations the methods are covered by different main groups of groups G11B3/00 - G11B7/00 or by different subgroups of group G11B9/00; Record carriers therefor using recording by magnetic means or other means for magnetisation or demagnetisation of a record carrier, e.g. light induced spin magnetisation; Demagnetisation by thermal or stress means in the presence or not of an orienting magnetic field
    • G11B11/105—Recording on or reproducing from the same record carrier wherein for these two operations the methods are covered by different main groups of groups G11B3/00 - G11B7/00 or by different subgroups of group G11B9/00; Record carriers therefor using recording by magnetic means or other means for magnetisation or demagnetisation of a record carrier, e.g. light induced spin magnetisation; Demagnetisation by thermal or stress means in the presence or not of an orienting magnetic field using a beam of light or a magnetic field for recording by change of magnetisation and a beam of light for reproducing, i.e. magneto-optical, e.g. light-induced thermomagnetic recording, spin magnetisation recording, Kerr or Faraday effect reproducing
    • G11B11/10502—Recording on or reproducing from the same record carrier wherein for these two operations the methods are covered by different main groups of groups G11B3/00 - G11B7/00 or by different subgroups of group G11B9/00; Record carriers therefor using recording by magnetic means or other means for magnetisation or demagnetisation of a record carrier, e.g. light induced spin magnetisation; Demagnetisation by thermal or stress means in the presence or not of an orienting magnetic field using a beam of light or a magnetic field for recording by change of magnetisation and a beam of light for reproducing, i.e. magneto-optical, e.g. light-induced thermomagnetic recording, spin magnetisation recording, Kerr or Faraday effect reproducing characterised by the transducing operation to be executed
    • G11B11/10504—Recording
    • G11B11/10508—Recording by modulating only the magnetic field at the transducer
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B11/00—Recording on or reproducing from the same record carrier wherein for these two operations the methods are covered by different main groups of groups G11B3/00 - G11B7/00 or by different subgroups of group G11B9/00; Record carriers therefor
    • G11B11/10—Recording on or reproducing from the same record carrier wherein for these two operations the methods are covered by different main groups of groups G11B3/00 - G11B7/00 or by different subgroups of group G11B9/00; Record carriers therefor using recording by magnetic means or other means for magnetisation or demagnetisation of a record carrier, e.g. light induced spin magnetisation; Demagnetisation by thermal or stress means in the presence or not of an orienting magnetic field
    • G11B11/105—Recording on or reproducing from the same record carrier wherein for these two operations the methods are covered by different main groups of groups G11B3/00 - G11B7/00 or by different subgroups of group G11B9/00; Record carriers therefor using recording by magnetic means or other means for magnetisation or demagnetisation of a record carrier, e.g. light induced spin magnetisation; Demagnetisation by thermal or stress means in the presence or not of an orienting magnetic field using a beam of light or a magnetic field for recording by change of magnetisation and a beam of light for reproducing, i.e. magneto-optical, e.g. light-induced thermomagnetic recording, spin magnetisation recording, Kerr or Faraday effect reproducing
    • G11B11/10502—Recording on or reproducing from the same record carrier wherein for these two operations the methods are covered by different main groups of groups G11B3/00 - G11B7/00 or by different subgroups of group G11B9/00; Record carriers therefor using recording by magnetic means or other means for magnetisation or demagnetisation of a record carrier, e.g. light induced spin magnetisation; Demagnetisation by thermal or stress means in the presence or not of an orienting magnetic field using a beam of light or a magnetic field for recording by change of magnetisation and a beam of light for reproducing, i.e. magneto-optical, e.g. light-induced thermomagnetic recording, spin magnetisation recording, Kerr or Faraday effect reproducing characterised by the transducing operation to be executed
    • G11B11/1053—Recording on or reproducing from the same record carrier wherein for these two operations the methods are covered by different main groups of groups G11B3/00 - G11B7/00 or by different subgroups of group G11B9/00; Record carriers therefor using recording by magnetic means or other means for magnetisation or demagnetisation of a record carrier, e.g. light induced spin magnetisation; Demagnetisation by thermal or stress means in the presence or not of an orienting magnetic field using a beam of light or a magnetic field for recording by change of magnetisation and a beam of light for reproducing, i.e. magneto-optical, e.g. light-induced thermomagnetic recording, spin magnetisation recording, Kerr or Faraday effect reproducing characterised by the transducing operation to be executed to compensate for the magnetic domain drift or time shift
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B11/00—Recording on or reproducing from the same record carrier wherein for these two operations the methods are covered by different main groups of groups G11B3/00 - G11B7/00 or by different subgroups of group G11B9/00; Record carriers therefor
    • G11B11/10—Recording on or reproducing from the same record carrier wherein for these two operations the methods are covered by different main groups of groups G11B3/00 - G11B7/00 or by different subgroups of group G11B9/00; Record carriers therefor using recording by magnetic means or other means for magnetisation or demagnetisation of a record carrier, e.g. light induced spin magnetisation; Demagnetisation by thermal or stress means in the presence or not of an orienting magnetic field
    • G11B11/105—Recording on or reproducing from the same record carrier wherein for these two operations the methods are covered by different main groups of groups G11B3/00 - G11B7/00 or by different subgroups of group G11B9/00; Record carriers therefor using recording by magnetic means or other means for magnetisation or demagnetisation of a record carrier, e.g. light induced spin magnetisation; Demagnetisation by thermal or stress means in the presence or not of an orienting magnetic field using a beam of light or a magnetic field for recording by change of magnetisation and a beam of light for reproducing, i.e. magneto-optical, e.g. light-induced thermomagnetic recording, spin magnetisation recording, Kerr or Faraday effect reproducing
    • G11B11/10595—Control of operating function
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B20/00—Signal processing not specific to the method of recording or reproducing; Circuits therefor
    • G11B20/10—Digital recording or reproducing
    • G11B20/10009—Improvement or modification of read or write signals
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B20/00—Signal processing not specific to the method of recording or reproducing; Circuits therefor
    • G11B20/10—Digital recording or reproducing
    • G11B20/10009—Improvement or modification of read or write signals
    • G11B20/10046—Improvement or modification of read or write signals filtering or equalising, e.g. setting the tap weights of an FIR filter
    • G11B20/10212—Improvement or modification of read or write signals filtering or equalising, e.g. setting the tap weights of an FIR filter compensation for data shift, e.g. pulse-crowding effects
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B20/00—Signal processing not specific to the method of recording or reproducing; Circuits therefor
    • G11B20/10—Digital recording or reproducing
    • G11B20/18—Error detection or correction; Testing, e.g. of drop-outs
    • G11B20/1816—Testing
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
    • G11B7/004—Recording, reproducing or erasing methods; Read, write or erase circuits therefor
    • G11B7/0045—Recording
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B20/00—Signal processing not specific to the method of recording or reproducing; Circuits therefor
    • G11B20/10—Digital recording or reproducing
    • G11B20/12—Formatting, e.g. arrangement of data block or words on the record carriers
    • G11B20/1217—Formatting, e.g. arrangement of data block or words on the record carriers on discs
    • G11B20/1258—Formatting, e.g. arrangement of data block or words on the record carriers on discs where blocks are arranged within multiple radial zones, e.g. Zone Bit Recording or Constant Density Recording discs, MCAV discs, MCLV discs
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
    • G11B7/24—Record carriers characterised by shape, structure or physical properties, or by the selection of the material
    • G11B7/2407—Tracks or pits; Shape, structure or physical properties thereof
    • G11B7/24085—Pits

Definitions

  • the present invention relates to a magneto-optical recording control method and an apparatus for enabling high-density optical recording.
  • One of the means for recording digital i on a recording medium is an optical disk device.
  • the optical disk focuses laser light on a recording surface by a lens, changes its intensity in accordance with the information to be recorded, and adjusts the reflectance and reflectance of the recording film in the area where the laser light is irradiated.
  • information is recorded by changing the magnetization direction by external magnetization or the like.
  • a laser beam with a lower intensity than that at the time of recording is irradiated, and changes in the amount of light from the reflected light from the recording film or rotation of the polarization plane due to a difference in the magnetization direction are detected. This is done.
  • the recording density is mainly determined by the size of the spot of the laser beam focused on the recording surface, and its size is as small as about 1 ⁇ m at present, so it is about 10 times the size of a magnetic disk High-density recording can be realized.
  • the mark length recording method in which information is recorded at positions before and after a recording mark recorded by modulating the irradiation light power, uses two or more data points per recording mark. This is an effective means for realizing high density.
  • the recorded mark shape is likely to be unstable. Also, if the recording linear velocity is different, the amount of heat applied per unit area and the distribution of heat are different, so that the recording mark shape is different. Therefore, in order to actually form a stable recording mark shape and perform recording / reproducing, “application of pit edge recording to PbTbSe film” (70th anniversary of IEICE) In the Commemorative National Convention Lecture Papers, p 4 — 1 7 6), the recording irradiation light pulse was set to be large, and the mark length was recorded so that it did not become longer than the target value according to the linear velocity. Adjustments are sometimes made to shorten the laser pulse length or to reduce the pulse length of the binarized signal during playback.
  • the shape of a recorded mark mainly depends on the recording sensitivity and thermal conductivity of the recording medium, the intensity distribution of the focused laser beam used for recording, the wavefront aberration, and the like.
  • the characteristics change when the combination of and the recording medium changes.
  • the level of the irradiation light power at the time of recording on the device side changes with time. This phenomenon is unavoidable even in the case where the laser power automatic control mechanism (APC) is provided, and fluctuations in the recording / reproducing characteristics also occur due to this factor. This fluctuation leads to fluctuations in the recording mark length during recording and fluctuations in the pulse interval of the reproduced signal during reproduction.
  • APC laser power automatic control mechanism
  • the recording correction amount and recording light power are set to constant values before shipment from the device, these setting specifications will be used for recording and playback with many combinations of recording media and recording devices. Determined after measuring characteristics. At that time, the combination In order to guarantee the reliability at the time of detection in all cases, taking into account the variation range of the recording / reproducing characteristics, a large margin is given to the recording density, and the recording density is sacrificed.
  • a test pattern is recorded in advance, and the reproduction signal is used to adjust recording conditions.
  • Methods for obtaining information have been proposed. For example, in the device described in Japanese Patent Application Laid-Open No. 6-11,394, the irradiation light power level, which is a constant value during recording, is set, and in the device described in Japanese Patent Application Laid-Open No. In the apparatus described in Japanese Patent Application Laid-Open No. 63-304427, both of them and the automatic equalization coefficient during reproduction are simultaneously adjusted.
  • optical discs are basically a recording method that uses thermal diffusion
  • the phenomenon in which the shape of a recording mark changes due to the diffusion of heat distribution due to a plurality of recording pulses before and after the recording mark (hereinafter referred to as “the recording mark”).
  • the recording mark the phenomenon in which the shape of a recording mark changes due to the diffusion of heat distribution due to a plurality of recording pulses before and after the recording mark.
  • Called thermal interference This phenomenon also leads to variations in the pulse interval of the reproduced signal during reproduction. Therefore, it is necessary to consider the effect of this thermal interference in order to perform the optimal correction during recording. As a countermeasure against this,
  • each recording pulse width is changed according to the interval to the immediately preceding recording pulse.
  • the conventional recording method is described in Japanese Patent Application Laid-Open No. 3-222223.
  • the recording code sequence of the recording mark is pulsed to form a series of pulse trains corresponding to the length of the recording code sequence, and the pulse sequence is recorded immediately before the recording code sequence of the pulse sequence length and amplitude.
  • control is performed according to the length of the reverse phase of a certain recording code string, the pulse string is divided into three parts 5, and recording is performed by changing the pulse width of each pulse.
  • the track on the disk is divided into a plurality of zones consisting of trackers, and the recording is performed so that the recording linear density is the same in the zone.
  • the optical disk device has already been described in detail in Japanese Patent Application No. 2-1333819.
  • the line density in each zone on the disk cannot be kept constant due to the recording / reproducing characteristics of the write-once film. It is higher than the recording linear density in the zone.
  • the above conventional technology does not take into account the fact that the recording sensitivity of the recording medium fluctuates due to fluctuations in the film thickness of the recording medium or fluctuations in the environmental temperature, and it is not possible to control the recording mark with high accuracy. There was a problem that caused the capacity to drop.
  • the length of the interval between multiple recording pulses of the recording irradiation light pulse has an effect due to the diffusion of heat, and as a result, the recording of the same length Even if a pulse is applied, the edge position will change depending on the combination of the recording patterns located earlier in time.
  • the thermal conductivity is generally large, and the range affected by the thermal interference is large.
  • this recording pulse width adjustment method uses a preset value irrespective of the recording condition at that time regarding the adjustment amount, so that the variation in the recording characteristics is affected.
  • the adjustment amount cannot be changed, and as much as the recording characteristic deviates from the setting, it appears as an error in the adjustment, making accurate adjustment impossible.
  • the recording irradiation light power or the single amount of the recording pulse width is adjusted, and the fluctuation of the recording mark length due to thermal interference is not reduced. .
  • a linear equalizer such as a transversal filter has been generally used in the field of communication and magnetic recording as a measure against intersymbol interference components on the reproducing side. This is to reduce the linear intersymbol interference generated by superimposing on the nearby waveform, because the frequency band of the signal reproduction system is narrow and the tail of the reproduction signal pulse is widened.
  • the effect of the thermal diffusion described above mainly appears as a waveform shift in the time direction during reproduction. This is a nonlinear intersymbol interference component that cannot be simply expressed as a linear superposition of the basic waveforms according to the recorded information. Therefore, the edge position fluctuation component cannot be handled by the linear equalizer, and it is actually very difficult for the reproducing side to deal with the interference component in real time.
  • the first object of the present invention is to provide a recording control method for precisely controlling the size of a recording magnetic domain, in particular, a magnetic domain length and a magnetic domain width, thereby providing a magneto-optical recording suitable for ultra-high density optical recording. It is to provide a recording control method of the recording.
  • a second object of the present invention is to propose a recording / reproducing apparatus for recording information at a high density using a magneto-optical recording medium. In particular, it proposes an effective method for recording on a disc.
  • a third object of the present invention is to suppress recording mark fluctuation due to the recording sensitivity fluctuation as much as possible and to perform highly accurate recording mark control.
  • a fourth object of the present invention is to improve compatibility between a recording / reproducing device and a recording medium and to suppress fluctuation in recording sensitivity due to the recording / reproducing device.
  • a fifth object of the present invention is to improve the reliability, storage capacity, and information transfer rate of a recording / reproducing apparatus.
  • factors that affect the size of the magnetic domain to be formed include environmental temperature, variations between recording media, and variations in laser power. When recording or erasing, these fluctuation factors are detected, and appropriate feedback is applied for recording or erasing, so that the formed magnetic domains do not interfere with each other. Density can be increased.
  • the data recording area on one disk is divided into a plurality of zones in the radial and track directions to obtain information necessary for performing recording control.
  • a recording condition can be found by providing an area for each zone and performing at least recording and reproduction in this area.
  • At least one type of information selected from the magnetic domain width, the magnetic domain length, and the interval between magnetic domains of the formed magnetic domains must be collected. I just need.
  • the user's data is recorded by controlling the laser at the time of recording, the control of the recording pulse width, or the waveform of the recording pulse.
  • the control is coarser than the previous case.
  • Information should be collected. This is because the information obtained here is mainly information on environmental temperature changes. Among them, the information obtained when a disc is inserted also includes variations in the sensitivity of the disc. This makes it possible to ensure compatibility of the medium.
  • a test track shall be provided to collect various data for recording control of at least one track in one sector or the entire circumference of one track. Is in the disk In order to eliminate the effects on these recordings due to variations in the recording or erasing when the recording or erasing is performed under a constant rotation speed, the heat flow differs for each zone and the recording conditions differ. It is.
  • This test track can be placed at any position within one zone, as long as it is representative of the characteristics of each zone.However, considering the usability, the first zone of each zone is considered. The part or end or the center of the zone is particularly preferred.
  • the data recording area on one disk is divided into multiple zones in the radial and track directions, and each zone has at least one track in one sector.
  • the entire circumference of one track was provided as a test track for collecting various data for recording control.
  • test Z erasure By performing test Z erasure on this track, it is possible to detect changes in the recording magnetic domain shape due to changes in environmental conditions and variations between recording media. Therefore, when recording is performed based on this information, a recorded magnetic domain having the same shape and the same size is always obtained.
  • a minute recording magnetic domain can be formed without being affected by disturbance, so that stable recording and Z reproduction can be performed. As a result, ultra-high density magneto-optical recording was realized.
  • a trial writing is performed in advance at a predetermined position on the recording medium, and the reproduction signal obtained by the trial writing and the trial are used. Written and compared with the night, after obtaining good results, regular information Start recording.
  • test writing data and the input data bit sequence of the legitimate information are used as the code sequence of the recording device, and the data sequence for recording the code sequence on the recording medium is generated.
  • the test writing is performed in advance at a predetermined position on the recording medium in order to improve the compatibility between the recording medium and the device that performs the recording.
  • fluctuations in the recording media such as fluctuations in the recording temperature due to fluctuations in the environmental temperature and changes in the characteristics of the recording device, etc. Performs an operation of writing on a recording medium before recording.
  • the reproduced signal obtained from the recorded test writing data is compared with the test writing data, and the light intensity or energy of the recording waveform for recording is changed so as to obtain a good result. Operates to match the recording medium with the recording device. As a result, the optimum recording conditions for the recording medium can be always obtained, so that the above-described information recording malfunction due to the fluctuation of the recording sensitivity is eliminated and the reliable recording / reproducing is performed. Can be done.
  • recording / reproducing is performed immediately after recording of regular information or at a certain period, the input data bit string is compared with the output data bit string, and if a malfunction occurs, the above-mentioned test writing is performed to improve reliability.
  • Recording and playback with in order to minimize trial writing performed immediately after recording of regular information or by recording / reproducing at a certain period, a recording pulse train and a recording auxiliary pulse corresponding to the recording mark are used. The length and width of the recording mark were controlled by keeping the temperature of the recording medium almost constant using two light intensities or two energy levels for the recording pulse train and the recording auxiliary pulse.
  • the quality of the recording conditions is determined without improving the amplitude and frequency characteristics of the reproduced signal. It is.
  • a recording pulse train and a recording auxiliary pulse corresponding to the recording mark of the trial data and the input data bit train of regular information are generated, and the recording pulse train and Recording assistance, It was recorded on a recording medium using two light intensities or two energy levels for the virus.
  • the recording power and the erasing power are reduced by modulating the light intensity of the recording pulse train and the recording auxiliary pulse in a recording medium on which information can be overwritten. It has been applied.
  • reproduction is performed immediately after recording the input data bit sequence of regular information, and the input data bit sequence and the output data bit sequence are compared.
  • the bit sequence is converted into a code sequence of a recording device, and a data sequence for recording the code sequence on a recording medium is generated, and a laser light source is driven to form a recording area on the recording medium. It controls the light intensity and energy level of the recording pulse train and recording assist pulse corresponding to the recording mark in the recording waveform to be recorded.
  • a device for recording and reproducing information concentrically on a disk-shaped recording medium in an optically identifiable form The track on the disk is divided into a plurality of tracks.
  • the recording is performed so that the recording linear density is the same in the zone, and in the inner circumference of the circle, the recording linear density in the zone is lower than the linear density in the outer zone. Lower.
  • the line density can be reduced on the inner circumference side, so that information can be read accurately even if there is thermal interference.
  • the contribution to the storage capacity that can fit on the entire disc of the inner track is not large, even if the linear density is loosened on the inner track, almost all It is possible to efficiently increase the density without reducing the capacity.
  • the fluctuation of the edge position of a recording mark due to thermal interference is temporally forward or rearward for each edge in accordance with a combination of a plurality of recording pulses positioned before the recording pulse.
  • Side adjustment, and adjust In addition to recording by the laser with the recorded recording pulse signal, a predetermined recording signal is recorded and reproduced at predetermined time intervals, and the light beam intensity and environmental temperature fluctuation at the time of recording are determined based on the result.
  • the recording mark length does not fluctuate under all recording conditions. Accurate information recording is performed, and more accurate recording mark edge position control for high-density recording by mark length recording can be realized.
  • Adjustment to shift the edge position of the recording mark due to thermal interference temporally forward or backward for each edge according to the combination of the immediately preceding plural recording pulses By performing recording with the laser using the adjusted recording pulse signal, it is possible to absorb the variation of the recording mark length when the recording pattern sequence differs due to the influence of thermal interference. it can.
  • the recording pulse can be accurately adjusted at any position on the recording medium.
  • the recording medium when the recording medium is replaced, and at predetermined time intervals, recording and reproduction are performed using a predetermined recording signal, and a recording mark section of the reproduction signal is performed.
  • the pulse length that hits the The duty with the gap length is detected, and the light beam intensity during recording and the deviation from the set value of the recording medium temperature are extracted from the information, and the light beam intensity during recording is set according to the result. If the value deviates from the set value, change the light beam intensity at the time of recording.If the temperature of the recording medium deviates from the set value, check the contents of the adjustment table or the light beam at the time of recording. If the intensity can be adjusted by changing the intensity, the light beam intensity during recording can be changed, and the recording pulse can be adjusted accurately even if the recording conditions fluctuate over time.
  • the present invention proposes a method for stably forming (recording) minute magnetic domains without thermal interference or the like, as the density of magneto-optical recording increases.
  • 1) a method using a recording pulse waveform, 2) a method using a recording method on a disk, and 3) a method in which test recording is performed and recording control information is obtained using the results. was suggested.
  • the recording capacity can be increased.
  • higher-density recording becomes possible.
  • the present invention typically includes, as shown in FIG. 1, a light source 8 for irradiating an optical disk 1 with a light beam, an encoder 4 for converting an information signal to be recorded into a code sequence, Modulates the light beam according to the train and converts it into a light pulse train.
  • An optical disc device comprising: a discriminator 15 for detecting a code string recorded on an optical disc from a pulse signal; and a decoder 17 for decoding a code string from the discriminator into an information signal.
  • An optical disc device characterized by controlling at least one of the power level of the nores, the width of the nores, and at least one of the pulse intervals.
  • the power level control includes a control means for controlling the modulation of the optical beam by selecting a pulse width or a pulse interval from predetermined values. This can be achieved.
  • the comparison results reflect at least one factor selected from the width, length, or mark spacing of the recorded marks.
  • Testo from trial writing means 3. It is desirable that the turn is encoded by the encoder 4 in the same manner as the data before recording.
  • Pulses electrical signal waveforms without passing through waveform processing means 1 1 It is more desirable to have a switching switch 12 for input to the means 13 and to evaluate the reproduced signal of the test pattern without passing through the waveform processing means.
  • One unit of the optical pulse train that forms one of the recording marks includes, for example, a leading pulse and a trailing pulse train having a different time width from the leading pulse.
  • the subsequent pulse train is easy to control if at least one of the pulse widths or pulse intervals is equal.
  • one unit of the optical pulse train forming one of the recording marks has a pulse having a power level equal to or higher than P w, and the optical pulse train not forming the recording mark has a power level equal to or lower than P as At least one of the front and rear sides of the optical pulse train that forms the recording mark has a power level region of Pr or less.
  • a train of optical pulses forming one of the recording marks may be configured to have two or more power level pulses.
  • the power level of the first pulse may be different from the power level of the subsequent pulse.
  • the control means controls the number of pulses of one unit of the optical pulse train forming one of the recording marks, or changes at least one of the Pw, Pas, or Pr.
  • the control means may control the optical pulse based on at least one of a combination of an optical disk temperature, a recording linear velocity on the optical disk, and a recording mark based on an information signal to be recorded.
  • the edge position of the pulse constituting the train may be controlled. It may be configured to have a table for storing information for controlling the edge position.
  • the optical disk is preferably divided into a plurality of zones having different recording conditions in the radial direction, for example, and it is preferable that each zone has an area for recording the test pattern.
  • the optical disk is divided into multiple zones in the radial direction, and the linear recording densities are equal in the same zone, and the bun on the innermost circumference of the optical disk has the lowest linear recording density. It is also desirable to configure it.
  • an optical pulse with at least one of the pulse width and pulse interval changed according to the zone or the radial position of the disk It is advisable to record using a data train.
  • the recording clock is used to control at least one of the pulse width and / or the pulse interval of the pulses constituting the optical pulse train, and the detection formed by the recording clock is used. It is preferable to set the window width to a fraction of an integer or an integral multiple.
  • the light source driving means 7 includes a plurality of unit driving circuits each including a switch means and a current source in series with the switching means, and one constant current source is disposed in series with each unit driving circuit.
  • the light source 8 is connected in series with the current source and in parallel with the unit drive circuit, and the current sources of the plurality of unit drive circuits supply different values of current.
  • a current value for driving the light source 8 is controlled by operating the switch means with a control signal based on the code string. At least one of the current sources of the unit drive circuit is variable in current, and light pulse control can be performed.
  • the switching means is preferably an npn-type switching element.
  • the information recording / reproducing method of the present invention converts an information signal to be recorded into a code sequence, modulates a light beam into an optical pulse according to the code sequence, irradiates the optical pulse sequence to a recording medium, and A code sequence is recorded as a recording mark by heat action or heat interference, and light from a recording medium is photoelectrically converted to obtain an electric signal waveform.
  • Optical signal recording that converts a signal from the waveform processing means into a pulse signal, detects a code string recorded on a recording medium from the pulse signal, and decodes the detected code string into an information signal.
  • a light beam is modulated by a specific test signal to form a test pattern on a recording medium, and the test pattern is reproduced and compared with the test signal, and the optical signal is generated based on the comparison result.
  • the power of the pulses that make up the pulse train Bell, pulse width, Wakashi Ku is an optical information recording and reproducing method according to Toku ⁇ that you controlling one also least for the pulse interval.
  • test pattern includes the longest code and the shortest code.
  • FIG. 1 is a device block diagram for explaining an embodiment of the present invention.
  • FIG. 2 is a flowchart illustrating the operation of one embodiment.
  • FIGS. 3 (a), 3 (b) and 3 (c) are conceptual diagrams illustrating the relationship between the recording method and recorded marks according to an embodiment of the present invention.
  • FIGS. 4 (a) and 4 (b) FIG. 4 (c) is a conceptual diagram illustrating the relationship between a recording method according to another embodiment of the present invention and a recorded mark
  • FIG. 5 is an explanatory diagram of a test writing recording pattern according to the present invention.
  • Figure 7 is an explanatory diagram showing the relationship between the thermal time constant and the temperature error after thermal shutdown.
  • FIG. 8 is a diagram illustrating one embodiment of a recording waveform.
  • FIG. 9 is a diagram illustrating another embodiment of a recording waveform.
  • FIG. 10 is a diagram illustrating a recording signal waveform.
  • FIG. 11 shows the recording signal waveform
  • Fig. 12 is a schematic diagram showing the reproduction signal waveform and the recording magnetic domain shape.
  • Fig. 13 is a diagram showing the pattern dependence of the edge shift.
  • Fig. 14 is a diagram showing the recording signal waveform.
  • Figure 15 shows the recording signal waveform.
  • Fig. 16 is a schematic diagram showing the reproduction signal waveform and the recording magnetic domain shape.
  • Fig. 17 is a diagram showing the pattern dependence of the edge shift.
  • Fig. 18 (a) shows the recording signal waveform.
  • Fig. 19 (a), Fig. 19 (b), Fig. 19 (c), Fig. 19 (d) are diagrams illustrating an embodiment of the laser drive circuit.
  • Figure 20 is a flowchart of the test writing procedure.
  • Fig. 21 is a schematic diagram showing the cross-sectional structure of a magneto-optical disc.
  • Fig. 22 is a diagram showing the shape of the recording pulse waveform.
  • Figure 23 is a block diagram showing the configuration of the embodiment.
  • Figure 24 is a schematic diagram showing how the edge position shifts due to mature interference.
  • Figure 25 is a diagram for explaining how to use the edge shift amount information to adjust the position of each edge of the recording signal to suppress the effects of edge shift.
  • Figure 26 shows an example of the recording signal pattern for recording condition measurement.
  • Fig. 27 shows the means for separating and detecting the light beam intensity change during recording and the temperature change of the recording medium from the measurement results.
  • Fig. 28 shows the flow of the recording condition judgment mode.
  • Figure 29 shows an example of the configuration of the edge interval measurement circuit.
  • Figure 30 is a diagram for explaining the operation of the edge interval measurement circuit.
  • Fig. 31 shows a configuration example of the recording condition determination circuit.
  • Fig. 32 shows a configuration example of the edge position adjustment circuit and the edge position adjustment table.
  • Figure 33 shows an example of the configuration of the edge position adjustment table switching circuit.
  • Fig. 34 is a graph showing the relationship between the recording radius position and the linear density.
  • Fig. 35 is a graph showing the relationship between the recording radius and the capacity contribution.
  • Figure 36 is a graph showing the relationship between the recording radius and the shortest domain length.
  • Figure 37 shows the waveform of the test pattern.
  • Figure 38 is a schematic diagram showing the recording domain shape.
  • Figure 39 is a plan view of the optical disk of the present invention.
  • Figure 40 is a waveform diagram showing the minimum change length.
  • FIG. 1 shows an optical disk device according to an embodiment of the device configuration of the present invention. It comprises a recording medium 1 for storing information, an optical head 2 for realizing recording and reproduction, and a processing system for converting a reproduction signal obtained from the optical head 2 into information.
  • the recording medium 1 rotates at a speed of 109, and comprises a recording film 101 and a substrate 102 holding the recording film.
  • the optical head 2 has a built-in optical system for focusing the light emitted from the laser 8 onto the recording medium 1.
  • the input data bit sequence (information) is input to the encoder 4, the recording code sequence output from the encoder 4 is guided to the recording waveform generator 5, and the recording waveform generator 5
  • the recording waveform obtained as described above is input to the APC 6, and light having an intensity corresponding to the recording code string is output from the laser 8.
  • the light reflected from the recording medium 1 is guided to the light receiver 9 by an optical system and converted into an electric signal.
  • the signal is input to a reproduction amplifier 10 and output to a waveform processing circuit 11 such as a waveform equalizer and an input switch 12. Input off
  • the transformer 12 outputs either the reproduction amplifier 10 or the reproduction signal from the waveform equalizer 11 to the shaper i 3, and outputs a pulse signal representing the presence or absence of the signal. Is converted.
  • the pulse signal is guided to the discriminator 15 and the PLL 14.
  • the synchronization signal (signal synchronized with the basic period of the pulse signal) output from the PLL 14 is input to the discriminator 15.
  • the discriminator 15 generates a detection code string from the pulse signal and the synchronization signal, and the decoder 17 outputs a data bit string (information).
  • the detection code string of the discriminator 15 is output to the comparison discriminator 16.
  • the test writing data from the test writing device 3 operated by the test writing instruction signal is input to the encoder 4 and converted into a recording code string.
  • the recording code string of the test writing data is recorded on the recording medium 1 via the same path as the recording information.
  • the input switch i 2 operated by the test writing command signal switches the output of the reproduction amplifier 10 to output to the shaper 13.
  • the laser driver that drives the laser 8 so as to compare the recording code string from the encoder 4 with the reproduction code string from the discriminator 15 and cancel the difference between the reproduction code string and the recording code string. Outputs a control signal to control APC 6 to control 7.
  • the difference between the reproduced code string and the recorded code string is reduced to some extent, and after reaching an allowable range, a test write end signal is output and the test write is completed.
  • the input switcher 12 switches the output of the waveform equalizer 11 to output to the shaper 13 and starts the normal recording / reproducing operation.
  • the discriminator 16 is used to confirm that the difference between the reproduced code string and the recorded code string is within an acceptable range. Start the write operation, and when the trial write end signal is output, continue the normal recording operation again.
  • the output of the input switch ⁇ 2 was operated so as to output the signal of the reproduced amplifier 0. Is more accurate. In the above operation, the same operation can be realized without using the input switch 12. However, in order to accurately detect the difference between the reproduced code string and the recorded code string in the comparison discriminator 16, it is better to use a signal that does not pass through the waveform equalizer 11.
  • the equipment is operated by turning on the power of the equipment (2021).
  • a test write operation is performed to confirm the compatibility between the inserted recording medium and the device (20025). , 20 23).
  • the test writing is performed so as to minimize the fluctuation of the recording mark caused by the fluctuation of the recording sensitivity to the recording medium due to the fluctuation of the film thickness of the recording medium or the fluctuation of the environmental temperature. And control the recording pulse, etc., and reduce the fluctuation of the recording device.
  • FIG. 3 illustrates the relationship between an embodiment of a recording method for recording on a recording medium of the present invention and recorded marks.
  • Figure 3 (a) shows the recording pulse for controlling the laser power.
  • the recording code sequence 20 corresponds to the recording mark recorded on the medium, and the recording waveform generator 5 generates a recording pulse sequence 21 in the pulse portion of the recording code sequence 20.
  • the recording pulse train 21 has the first pulse and the second and subsequent pulses having different lengths, and the pulse length of the second and subsequent pulse trains has the minimum change length of the recording mark (multiple types).
  • At least one pulse corresponds to the minimum change in the length of the light pulse when forming a mark of length.
  • a recording pulse train in which the influence of heat from other pulses near the final falling position of the pulse of the recording mark is almost negligible, or a recording in which a constant heat inflow occurs. It consists of a 'pulse train'.
  • a recording auxiliary pulse 22a is generated in the gap part (pause period part other than the pulse part) of the recording code string 20.
  • the recording auxiliary pulse 22a has a final fall of the recording pulse train by providing a gear portion in which the laser power is reduced for a certain period from near the falling position of the recording code train 20. So that the heat from the position does not affect the temperature at the leading edge of the next recording pulse train.
  • Figure 3 (b) shows the recording of the laser power when the laser 1 is driven using the recording pulse train 21 and the recording auxiliary pulse 22a.
  • the horizontal axis' is the time on the horizontal axis, and the laser power is the vertical axis. It was expressed as-.
  • the minimum level of the laser power is playback ⁇ —pr during playback.
  • the highest level of laser power is recorded.
  • the middle level is the recording assist pulse 22 a of the recording assist pulse ⁇ -P as.
  • the length and width of the recording mark 23 on the recording medium are controlled with high accuracy using such a laser power waveform.
  • the width of the recording mark 23 is controlled within a certain range, so that the amplitude of the reproduction signal 24 becomes constant.
  • a reproduced code string 25 is generated.
  • the length of the pulse portion, the rising position or the rising edge of the pulse in the recording code string 20 in FIG. 3A and the reproduction code string 25 in FIG. 3C are shown. Evaluate by comparing the intervals such as the descent position. For example, when the recording power is too large, the pulse length of the reproduction code string 25 becomes longer than the pulse length of the recording code string 20. On the other hand, the pulse length of the reproduction code string 25 is shorter than the pulse length of the recording code string 20.
  • the detection method has already been described in detail in “Digital Signal Recording / Reproducing Apparatus” filed by the inventors of the present invention in Japanese Patent Application Laid-Open No. Hei 4-61028.
  • a new method that does not increase the size of the detection circuit.
  • a recording pattern used as a test pattern for example, a shortest recording mark and a longest recording mark determined from a recording modulation code as shown in FIG. 5 are alternately recorded. If 117 modulation is used as the modulation method, the length corresponding to 1.33T, 5.33 ⁇ where T is the bit period is good.
  • the reproduced waveform will be a fundamental wave without harmonic components. Generally, this playback waveform is affected by both the length and width of the mark because the shortest mark is smaller than the diameter of the playback spot.
  • the signal amplitude of the reproduced waveform of the longest mark is determined only by the effect of the width, and the signal rise and fall intervals are the mark length. It corresponds to.
  • the width of the longest recording mark and the shortest recording mark can be made almost equal, so the difference between the reproduction waveforms of the shortest mark and the longest mark is obtained. Can be regarded as a difference in length.
  • the so-called mark length recording in which information is given to both edges of the mark, is performed, and a direct slicing method is adopted as a binarization method for converting this into a data pulse.
  • Level must be determined accurately. This level has the same mark width, and if the shortest mark length is longer than half the optical spot diameter, it should be set to half the amplitude level of the longest mark length. I know it. In other words, if the mark length is longer than half of the optical spot diameter and there is an optical spot on the mark edge, the playback signal from this mark edge will be the edge of the adjacent mark.
  • the point of intersection with the reproduced waveform when slicing at the half value of the amplitude determined by the longest mark length corresponds to the edge of the mark because it is not affected by the mark.
  • the binarization circuit 610 binarizes the signal at the slice level where the playback waveform can be varied, and forms pulses.
  • the integration circuit is started at the rising edge of the pulse, charged, and discharged at the falling edge.
  • Sample hold comparator 603 samples and holds the value of the integrator at the next rising pulse, and slice controller 604 sets the slice level so that the sample hold value becomes zero.
  • a feed knock is applied to the binarization circuit 601 so that it changes, and when the slice level is determined, this slice level is analog-to-digital converted by the AZD converter 605. And stored in the memory circuit 606. This operation is determined in the same way for the shortest mark and the longest mark, and if the respective values are VI and V2, the recording conditions are changed so that the difference becomes zero.o
  • FIG. 4 shows another embodiment of a recording method for recording on a recording medium according to the present invention.
  • the recording code string 20 is converted into a pulse portion of the recording code string 20 by the recording waveform generator 5.
  • a recording pulse train 21 is generated.
  • the recording pulse train 21 has a different length from the first pulse and the second and subsequent pulses, and the pulse length of the second and subsequent pulse trains corresponds to at least one pulse within the minimum change length of the recording mark.
  • a recording pulse train in which the influence of heat from other pulse trains in the vicinity of the final falling position of the recording mark pulse can be almost neglected, or a recording pulse train in which a constant heat flow occurs. It is composed of
  • a recording auxiliary pulse 22b is generated in the gap of the recording code string 20 (corresponding to the interval between recording marks in the rest period other than the pulse).
  • the recording auxiliary pulse 22b is generated by providing a portion where the laser power is lowered for a predetermined period before the rising position of the recording code string 20 and from the falling position of the recording code string 20 for a predetermined period. The heat from the last falling position of the pulse train hardly changes the temperature at the first rising position of the next recording pulse train.
  • the horizontal axis indicates the time and the vertical axis indicates the change according to the recording code string of the laser power.
  • the minimum level of laser power is the playback level during playback. ⁇ — pr
  • the high level during recording is the recording power P w of the recording pulse train 21
  • the low level during recording is the recording power of the recording auxiliary pulse 22 a.
  • P-P as. Using a recording waveform like a graph, the length and width of the recording mark 23 on the recording medium are controlled with high precision.
  • the temperature on the recording Since the change in the width of the recording mark 23 is controlled within a certain range, the amplitude of the recording portion of the reproduction signal 24 becomes substantially constant. A discrimination at the center of the reproduction signal 24 or at a certain level generates a reproduction code string 25.
  • Tmax The maximum temperature reached by the recording pulse
  • K Pr the temperature rise due to the reproduction laser power
  • K ′ The environmental temperature of the apparatus
  • K ′ the temperature rise due to the recording laser power
  • f (t) be the function for time t, which represents the rate of temperature decrease after the recording pulse irradiation
  • g (t) the function, which represents the rate at which the temperature rises after the auxiliary pulse is irradiated.
  • the first term on the right side is the effect of the recording pulse of the previous mark
  • the second term is the effect of the recording auxiliary pulse.
  • To cut off the recording auxiliary pulse means to control the coefficient of the second term. If the recording auxiliary pulse is not cut off, this term will be constantly zero, and the recording will be performed in principle. The effect of the pulse cannot be eliminated. From Equation 6, it can be seen that to eliminate the effect of the recording pulse of the previous mark, E (2Tw) should not be in a temperature error where the shift of the mark edge has almost no effect. must not.
  • Equation 3 shows the relationship between the recording auxiliary pulse, the recording pulse, and the ambient temperature
  • Tmax Tr + KPr + KPas '+ K'P'
  • Equation 7 Equation 7 is obtained.
  • TmaX determines the mark width when the spot shape, linear velocity, and thermal conductivity of the medium are determined, and also determines the mark length when the above-mentioned recording pulse waveform is determined.
  • T max In order to keep the width and length constant, T max must be kept constant. The right side of 7 must be constant. Then, once the environmental temperature and regeneration level are determined, the sum of pw 'and Pas' must be constant.
  • the factors that determine K here are the spot shape, the linear velocity, and the heat transfer characteristics of the medium, and K 'is these and the recording pulse waveform.
  • Equation 6 in order to reduce the error, the function of f (t) and (t) is a function that expresses the rate of decrease and increase in temperature, so that only a value between 1 and 0 can be obtained.
  • KP as' and K 'P' to be almost equal because the tolerances for f (t) and g (t) become wider.
  • ⁇ (t) and g (t) are determined by the heat conduction characteristics of the medium, and as described above, f (t) can be related to the linear velocity and the heat conduction velocity.
  • G (t) is determined by the heat capacity and linear velocity of the film.
  • Equation 9 As described later, it is very convenient for the circuit realization that the recording waveform is synchronized with the recording clock. Then, the time t is expressed in the unit of the detection window width Tw of 17 modulation.KP as 'is 80 degrees, K'Pw' is 100 degrees, and the cutoff time. Assuming that the temperature error of Tw and T (2Tw) is within ⁇ 10 degrees, the combination of tau 1 and ta ⁇ 2 that satisfies this condition is as shown in Figure 7. This value is obtained by using a magneto-optical recording film and the medium described in JP-A-6-19004, and when the linear velocity is 9.4 m / s and Tw is 40 ns, the edge shift is Tw.
  • the square region indicates the region where the steady state is reached immediately because the rate of attenuation increase is fast.
  • the area where the heat is balanced by the cutoff is the shaded area, which is determined by the four combinations of Pw ', Pas', f (2Tw) and g (2T) described above. Area. Even if each element of the four combinations fluctuates, it is desirable to select a square region as the region in order to reduce the temperature error. In particular, if taul is set to 0.4 or less, the effect of K'Pw 'is greatly suppressed, and the allowable range for cutoff time and tau2 is expanded.
  • the absolute time of Tw changes depending on the radial position, but all the results so far can be satisfied if the cutoff time and time constant are standardized by Tw I do.
  • the recording pulse in order to record the shortest mark of 1 to 7 modulation in FIGS. 3 and 4, a combination of the first pulse of the time width Tw and one subsequent recording clock pulse is used.
  • the recording clock generally oscillates with a Tw period, and it is convenient to use this for the convenience of the circuit.
  • the shortest mark is recorded by a pulse with a recording power change W1 of length a.
  • the shortest mark having a desired width and a length of 1.33T can be recorded by a combination of the recording auxiliary pulse of the P as level and this recording pulse.
  • the recording power is recorded as the recording power variation W2 using the above-described recording clock.
  • the maximum temperature reached for each recording clock is made constant. In Fig. 8, the temperature at each point from timing t2 to t6 is determined.
  • the pulse width of a is created from a pulse width of 2 Tw using a delay line or the like.
  • the maximum attained temperature of each pulse can be made equal.
  • the drawback of this method is that, as is clear from Equation 10, even if one medium is determined, there are fluctuations in the recording pulse width a and d, and fluctuations in the recording device such as changes in the rise characteristics of the laser drive circuit. Since Q and R change, the temperature at each timing is different and cannot be corrected.
  • the recording clock is used as it is, and the power for recording the shortest mark and the power of the succeeding pulse are changed to W1 and W2, respectively, and the recording assistance pulse at the Ps level is used.
  • the power W 1 that forms the shortest mark with a length of 1.33 T with the two recording clocks is determined. Based on the timing t1 force, the temperature reached at t5, and the temperature at t2 and t3, W2 is calculated from
  • Equation 11 Equation 11 is obtained.
  • the effects of fluctuations in the recording device such as fluctuations in the recording pulse width and changes in the rise characteristics of the laser drive circuit, are caused by a uniform change in temperature at each timing.
  • the effect of this can be eliminated by the writing for the present invention because it is changed. That is, since the temperature change is constant regardless of the mark length, it can be corrected by changing the recording auxiliary pulse.
  • a You can set it to Tw.
  • Equation 7 explains the relationship between the test writing operation and various variables.
  • the change of the auxiliary light P as ′ is changed to keep T max constant.
  • the temperature of recording changes when the film thickness of the recording medium changes or the recording sensitivity changes, but it can be considered that the Tma force, the 'Tmax1 force', and the like change to Tmax2 effectively. Therefore, the variation of the auxiliary light, P as', is controlled to compensate for this variation.
  • the fluctuation of the recording power results in the change of PrP as' P w ', but also in this case, the change of the auxiliary light, P as', can keep T max constant. For this reason, KP as' must be about the same as K 'P w'. Variations in the recording characteristics due to the recording / reproducing device are variations in K and K ′, which can also be kept constant by changing the variation P as ′ of the auxiliary light.
  • FIG. 10 is a schematic diagram showing the shape of the recording pulse used.
  • the recording power is 6.5 mW at the innermost position of the disk where the rotation of the disk medium is 300 rpm, and the difference between the first and second lures of the recording area is 6.5 mW.
  • the noise of the third and subsequent pulses was 6 mW.
  • the power of the preheat is a few mW, and the pulse width and the gap interval are all 20 ns. This interval is set from the recording clock.
  • the disk medium of this embodiment is Although the case where the head pulse is increased is shown, this may be reduced depending on the structure of the recording medium. Recording was performed on the disk using the optical pulse in Fig. 10.
  • a low-power portion between the recording pulses was provided immediately after the recording pulse, and the period was set to 40 ns.
  • Fig. I 2 shows a schematic diagram of the reproduced signal waveform and recorded magnetic domain when the shortest 1.33T mark is recorded after the longest 5.33T mark using the RLL modulation method. Shown in Here, the formed magnetic domain width is 0.7 / m, and the magnetic domain length is 0.75 m at the shortest and 3.0 m at the longest. From this figure, neither the shortest domain nor the longest domain is affected by each other, the domain width is constant independent of the pattern length, and the shortest 1.33 T Is recorded after 5.33 T, all 1.33 T magnetic domains have the same length, indicating that the previous magnetic domain is not affected by heat. .
  • Figure 13 shows the difference between the pulse width of the recording signal and the width of the reproduction signal when recording various patterns based on (1,7) modulation. According to this figure, the edge shift at that time was 5% or less of the detection window width without depending on the formed magnetic domain length.
  • Toko furnace returns slow the record Z playback / erase, 5 X 1 0 even after the seventh surface repetition of Canon Li ⁇ level and changes in the Roh I Zureberu is has failed seen. Similar effects were obtained by using any of the pulse shapes shown in FIGS. 11 and 14 other than those shown in FIG. Here, the pulse and the gap interval were both set to 2 O ns.
  • the first pulse width is. For Turn I, 7.5 mW is appropriate and. For Turn ⁇ I, 6.7 mW was optimal. However, these values are selected depending on the thermal structure of the medium used.
  • the power of the first pulse is as low as 5.5 mW, and the power of the second and subsequent layers is low.
  • the shift could be suppressed to 2 nm or less.
  • FIG. 1 A schematic diagram showing the shape of the recording pulse used is shown in FIG.
  • the recording power was 6.7 mW at the innermost position at the rotation of the disk medium at 300 rpm, and the subsequent power was 6 mW.
  • the preheat power is 2.3 mW, the leading pulse width is 55 ns, and the subsequent pulse width and gap interval are both 20 ns.
  • the pulse was recorded on the disk using this pulse.
  • Figure 16 shows a schematic diagram of the reproduced signal waveform and the recorded magnetic domains when the shortest 1.33T is recorded after the longest 5.33T using the (1,7) RLL modulation method.
  • the formed magnetic domain width Is 0, the minimum domain length is 0.75 ⁇ m and the maximum is 3.0 ⁇ 1.
  • the domain width is constant independent of the pattern length, and the shortest is 1.33 mm. Even when three pieces of data are recorded after 5.33 ⁇ ⁇ , all the 1.33 1. magnetic domains have the same length, indicating that the previous magnetic domain has not been affected by heat.
  • Figure 17 shows the difference between the pulse width of the recording signal and the width of the reproduction signal when recording various patterns based on (1, 7) modulation. According to this figure, the edge shift at that time was 5% or less of the detection window width without depending on the formed magnetic domain length.
  • the magneto-optical recording medium has a structure that is easy to warm and easy to write, it is necessary to make the first pulse longer at the same time as the pre-heat at the same time as the pre-heat, so that the pulse width is longer than the subsequent pulse. is there.
  • the pulse width be an integral multiple of the recording clock or a fraction thereof.
  • FIG. 19 shows a specific configuration of a laser drive circuit for realizing test writing according to the present invention.
  • the driving circuit shown in FIG. I w 2, las, and Ir are set so that the laser light has a predetermined power in consideration of the current-to-light conversion efficiency of the laser and the efficiency of the light head. Since only Ias is controlled by trial writing, it should be variable.
  • this current switch circuit does not use the P np type to increase the response with + drive, but switches using the npn type. Therefore, it has a special drive circuit configuration.
  • the current source I shown in Fig. 19 (d) constantly supplies the maximum current, and the current source I on the current switch side is set by the current switch CS.
  • the configuration is such that the current flowing to the laser is reduced only by the current values of r, Iw1, Iw2, and Ias. Therefore, the pulses PrPw1 and Pw2Pas that control the current switch must have polarities inverted from those of the optical recording waveform.
  • the above-described recording pattern is recorded in one track by changing the size of the recording auxiliary pulse for each sector indicating a data break. If the number of sectors is 5.25 inches in diameter and the line density is about 0.56 micron / bit, there are 32 in the MCAV recording system even on the inner circumference.
  • the amount of change of the auxiliary light is changed in five steps. At first, it is changed by 5 steps. This is done the first time the disk is loaded and when the disk is replaced. Next, it is determined which change amount has changed greatly. Then, the interval is further divided and changed in 5 steps.
  • Figure 20 shows the test writing procedure.
  • the most severe condition for the frequency of trial writing is from when the device is turned on to when the temperature reaches a temperature at which the heat can be balanced. Although it depends on the heat generation conditions of the circuit, the temperature rises by about 10 ° C in 5 minutes at the maximum. If set at the beginning, it can be controlled well every 5 minutes.
  • a test write operation is performed when the optical disk is replaced, when the device is turned on, or at an appropriate time during the operation of the device (2001).
  • an area for trial writing on the medium is selected (2002).
  • a dedicated area (test writing track area) is set for the outer, inner, or middle track of the optical disc.
  • test writing test pattern is recorded on this track.
  • the test pattern is shown in, for example, FIG. 5, FIG. 25, and FIG. 3, FIG. 4, FIG. 8, FIG. 10, FIG. 11, FIG. 11, FIG. 14, FIG. What is recorded in the recording pulse train is used.
  • recording of one round of the track was performed by changing the power Pas of the recording assist pulse for each sector by using the pattern of FIG. 5 (2005-200). ).
  • the recorded test pattern is reproduced (210, 210) and evaluated. Evaluation is based on the test pattern This was performed by taking the difference ⁇ V between the center level V 1 of the reproduced waveform of the turn and the center level V 2 of the reproduced waveform of the least sparse pattern (201 2). The value of is taken in for each sector (20
  • the recorded test and turn are deleted (201-16).
  • the value of P as at the sector where ⁇ V was the minimum was determined as the optimum power of the recording auxiliary pulse (201). In this embodiment, this operation is performed on each of the outer circumference, inner circumference, and middle circumference of the optical disk (210-18). After the end, the normal data recording operation is started (201).
  • FIG. 21 is a schematic diagram showing the cross-sectional structure of the disk used in this example.
  • the recording medium was formed on a plastic or glass substrate having uneven guide grooves by a sputtering method.
  • continuous lamination was performed.
  • the reason why the continuous lamination is performed is to suppress formation of an impurity layer such as oxygen at a layer interface.
  • this laminated structure is only one example, and the effect of the present invention is not provided by the laminated structure.
  • minute magnetic domains can be stably formed, so that ultra-high density optical recording can be realized.
  • the magneto-optical disk having a four-layer structure is shown here, the effect of the present invention is not related to the number of the layer structures.
  • This disk has the pulse shape shown in Fig. 21. Recording was performed using the following waveforms.
  • the pulse width of the recording waveform is synchronized with the write clock of the disc device. This is advantageous not only in the ease of making a clock signal and in reducing the cost of the device, but also in that the accuracy of the clock is high.
  • the shortest 1.33 T bit in this modulation method was formed with a pulse width of 6 O ns and a laser power of P w 1. Thereafter, after passing through the 20 ns P ass level, a 2 T bit is formed at 20 ns P w 2, and by repeating this operation, 2.66 T to 5.33 T Pulse was formed.
  • the ratio of the laser width to the laser power varies depending on the structure of the disk and the material used, and is determined in consideration of the compatibility between the device and the disk. That is,
  • P 1 P w 2 P w l> P w 2 in some cases.
  • the magnetic domains recorded by the above method were reproduced (using the front and rear edge independent reproduction method).
  • the wind margin was 30% and the shift was less than ⁇ 2 ns.
  • the pattern used for the measurement is random.
  • SiNx is used as a material, but optical absorption is not required.
  • the dielectric material is an inorganic compound, at least one compound selected from the group consisting of silicon nitride, aluminum nitride, and silicon oxide should be used. Can be done.
  • Al 96 Ti 4 was used as a metal layer for controlling light reflection and heat flow, but a smaller number of metals selected from Au, Ag, Cu, Al, Pd, and Pt was used. At least one element is used, and in order to control thermal conductivity, in addition to the elements other than the above-mentioned parent elements, a small number of elements selected from Nb, Ti, Ta, and Cr are used. In each case, a film in which one element is added in an amount of 0.5 at% or more and 3 O at% or less can be used.
  • Figure 23 schematically shows how the edge position shifts due to thermal interference.
  • the horizontal direction represents the passage of time or the spatial coordinates on the recording medium where the optical spot moves.
  • the recording signal 201 modulates the recording information and shows the temporal transition of the intensity of the light spot irradiated on the recording medium
  • the recording mark 23 shows the recording signal 201 on the recording medium according to the recording signal 201. It shows the shape of the recording mark formed on the surface.
  • the reproduction signal 24 is read from the recording mark 23 and scanned by an optical spot having a light intensity of a level, and the reflected light from the recording medium at that time is received by a photodetector and photoelectric conversion is performed. And obtained.
  • Binary reproduction signal 2 Numeral 5 is obtained as a result of binarizing the reproduced signal 24 reflecting the recording mark shape according to whether the signal level is above or below a predetermined signal level.
  • FIG. 23 shows the first rising edge of the recording signal 201, the leftmost front edge position of the recording mark 23, and the first rising edge position of the binarized reproduction signal 25. They are displayed together.
  • L [i] and B [i] are the pulse intervals (from the rising edge to the falling edge) of the recording signal 201 and the gap interval (from the falling edge to the rising edge).
  • I) represents the serial number (0 initially) from the first recording pulse (binary reproduction pulse).
  • the heat given by the optical spot is generated during the cooling process.
  • the temperature around the optical slot rises. Therefore, in order to perform high-density recording, when the size of the recording mark and the interval between them are reduced, the pulse shape of the recording signal not only determines the corresponding recording mark shape, but also determines the surrounding recording mark shape. It also affects the recording mark shape. Conversely, the shape of each recording mark is not determined only by the corresponding recording pulse shape, but is affected by the temporally adjacent recording pulse shapes.
  • the recording mark is a temporally adjacent recording pulse
  • a deviation occurs between the pulse interval of the recording signal 201 and the edge position of the recording mark 23.
  • relative deviations e [i] and f [i] between each edge position of the recording signal and each edge position of the binarized reproduction signal 25 are generated.
  • e [i] is the amount of deviation between the falling edge of the recording signal 201 and the falling edge of the binarized reproduction signal 25
  • f [i] is the recording signal 20
  • the difference between the rising edge of 1 and the rising edge of the binarized reproduction signal 25 is shown.
  • i is a serial number (0 at the beginning) from the rising edge and the falling edge of the first recording pulse (binary reproduction pulse), and f [0] is zero.
  • the edge shift amounts e [i] and f [i] vary depending on the heat conduction characteristics and the recording density of the recording medium.
  • the most common as a magneto-optical recording medium is For a recording medium with a structure consisting of a TbFeCo magnetic film, a dielectric film, a protective film, and a reflective film, the recording linear velocity is about 10 to 20 m / s, and the shortest recording mark length as recording density is light.
  • the spot diameter is about half of the spot diameter, it can be expressed by the following equation using the pulse length L [i] of the recording signal and the gap length B [i].
  • S e () and S f () represent functions. That is, e [i] is the immediately preceding pulse interval L [i] Determined by the previous gap interval B [i-11], f [i] is determined by the immediately preceding gap interval B [i1-1] and the preceding pulse interval L [i1-1]. It will be decided.
  • the horizontal direction represents the passage of time or the spatial coordinates on the recording medium where the optical spot moves
  • the recording signal 301 is an electric signal that modulates the recording information
  • the signal 302 represents the temporal transition of the electric signal level in which the rising and falling edge positions of the recording signal 301 are shifted according to the recording pattern. Modulating spot intensity.
  • the recording mark 23 indicates the shape of the recording mark formed on the recording medium by the adjusted signal 302.
  • the reproduction signal 24 is obtained by reading the recording mark 23 and operating it with the light spot having the light intensity of the level, receiving the reflected light from the recording medium at that time with the photodetector, and performing photoelectric conversion. It is.
  • the binarized reproduction signal 25 is an electric signal reflecting the recording mark shape, which is above or below a predetermined signal level. The electrical signal obtained as a result of the binarization depending on the side.
  • the first rising edge of the recording signal 301, the leftmost front edge of the recording mark '23, and the first rising edge of the binarized reproduction signal 25 are defined as follows. It is written together.
  • L [i] and B [i] are the pulse intervals (from the rising edge to the falling edge) of the recording signal 301 and the gap interval (from the falling edge).
  • E [i] and F [i] are the recording signals 3101 related to the falling edge and rising edge of the adjusted signal 302, respectively. The deviation amount from each edge position is shown.
  • i represents the serial number (0 initially) from the first recording pulse (binary reproduction pulse).
  • the principle of adjusting the recording pulse edge position is as follows.
  • the edge of the recording mark 23 always deviates from the edge of the recording signal 301.
  • each of the binarized reproduction signals 25 is obtained.
  • the edge position deviates from the edge position of the recording signal 302, but coincides with the edge position of the original recording signal 301.
  • the amount of deviation of the edge position of the recording mark 23 from the edge position of the recording signal 301 is determined by referring to the recording pattern using the relational expression described above by referring to the recording pattern. Required. Therefore, the inverse function of this relational expression
  • the amount of shift of the edge position and the amount of shift of the binarized reproduction signal with respect to the recording signal can be determined so that the sign is reversed and the magnitude is the same. That is,
  • Equation 18 the functions C e () and C f () include the edge position shift amount. However, the shift amounts are E [0], F [1], E [1], F [2],
  • each edge position of this recording mark differs for each recording mark formed. Therefore, when the light beam intensity during recording changes, the deviation of the edge position of the recording mark that occurs is reduced by changing the edge adjustment amount for each recording pattern as described above.
  • it is necessary to change the edge adjustment function for each light beam intensity at the time of recording which requires a large-scale circuit system. Therefore, in order to prevent edge misalignment with a simpler system, if it is detected that the light beam intensity during recording has changed, the light beam intensity during recording is returned to the original value. Make the necessary adjustments.
  • the recording mark becomes smaller as a whole.
  • the position of the front edge of the recording mark is on the rear side and the position of the rear edge of the recording mark is on the rear side.
  • the position of the edge is shifted to the front.
  • This temperature fluctuation is Unless a temperature control mechanism is provided inside, it is not possible to directly control the temperature directly.
  • the edge position fluctuation characteristic of the recording mark due to the temperature fluctuation shows a tendency that is close to the case where the light beam intensity at the time of recording changes in a range where the fluctuation amount from the assumed temperature is small. Therefore, in this range, the change is made by changing the light beam intensity at the time of recording, and the function for adjusting the edge position at the time of recording is switched when the value greatly fluctuates from the set value.
  • a predetermined recording signal is recorded in a dedicated area on the recording medium at predetermined time intervals. Immediately after that, the signal is reproduced to detect the deviation amount of each edge position, and from the result, the change of the optical beam intensity during recording and the temperature change of the recording medium must not be separately detected.
  • FIG 25 shows an example of the recording signal pattern used at that time.
  • the recording signal 401 has a plurality of edge intervals within the range of the recording mark length that can be obtained during normal information recording, and a pulse width and a pulse interval immediately after the pulse width from the shorter or longer one. Arrange them so that they are equal, and use one that is repeated several times. The reason for using the repetition is to reduce the influence of noise components included in the detection result and improve the accuracy of the measurement result by the averaging process.
  • the recording signal is configured to be code-modulated by 2 to 7 RLLC (Run Length Limited Code) with respect to the recording information, and P w [1 ), P w [2],. Represents the edge interval of the recording signal pulse, Gw [1], Gw [2], and... Represent the edge interval of the recording signal gap.
  • T in the other edge interval of the recording signal 401 is the time length per bit of information.
  • the reproduction signal 402 represents the reproduction signal waveform after binarization when the recording mark written by this recording signal is read.
  • P r [1], P r [2], ... are the edge intervals of the playback signal pulse
  • G r [1], G r [2], ... are the playback signal pulses. Indicates the edge interval of the tip.
  • FIG. 26 shows a means for separating and detecting a change in the light beam intensity during recording and a change in the temperature of the recording medium from the relationship between the recording signal 401 and the reproduction signal 402.
  • the pulse interval Pw [i] of the recording signal 401 was subtracted, and on the vertical axis, the immediately following gap interval Gr [i] was subtracted from the pulse interval Pri of the reproduced signal 402.
  • the measurement points for each recording situation are plotted. If the entire measurement point is above the 0 level in this measurement result, the light beam intensity during recording has changed in a direction larger than the set value, or the temperature of the recording medium has exceeded the expected value. This is the case when it changes in a higher direction. Conversely, if the entire measurement point is below the 0 level, the light beam intensity during recording has changed in a direction larger than the set value, or the temperature of the recording medium has changed. This indicates that the value has changed in a direction higher than the expected value.
  • FIG. 27 is a block diagram showing the configuration of the embodiment.
  • the optical disk 1 is rotated at a constant angular velocity by the spindle motor 109, and the laser light for recording / reproducing by the optical pick-up 2 The light is focused on the recording film surface on step 1.
  • the optical pickup 2 can be moved in the disk radial direction in accordance with the information recording position.
  • the signal detected by the detector in the optical pickup 2 is amplified to a desired level by the amplifier 10 and then equalized by the equalizing circuit 11. Therefore, the resolution of the reproduced signal is secured. After that, this signal is converted to a reproduced binary signal 277 which is a digital signal by the binarization circuit 13, and is converted by the PLL (Phase 'Lock' Zolpe) circuit 14. The signal is separated into a clock signal and a data signal, and is reproduced by the demodulation circuit 17.
  • the reproduction signal processing system of the present invention detects changes in the optical beam intensity during recording and the temperature on the recording medium, and calculates and updates the pulse interval adjustment amount during recording and the recording power. It has a circuit system.
  • This circuit system includes an edge interval measuring circuit 270 and a recording condition judging circuit 271.
  • the reproduced binary signal 277 passes through the edge interval measuring circuit 270, and the pulse interval and the gap interval are measured.
  • the measurement result is input to the recording condition determination circuit 11, where the change in the light beam intensity during recording and the temperature change on the recording medium are separated and detected, and the result is used as the controller 27 2 Sent to.
  • This recording condition judging circuit operates in a recording condition judging mode instructed by the controller at predetermined time intervals other than during normal information recording / reproducing.
  • Figure 28 shows the flow of this recording condition judgment mode.
  • a predetermined time interval is monitored by the controller 272 in the system, and this mode is started at each time interval (2031) .
  • the system is set to a busy state at the beginning of this mode so that normal recording / reproducing operation is not accepted (2032), and if the work (recording, If there is (playback), wait for the processing to end (2033) o
  • the optical spot is moved to a dedicated area for recording and reproducing a predetermined recording signal for examining recording conditions (2034).
  • This area should be set at a plurality of locations with different turning radii per recording medium.
  • the light beam intensity at the time of recording changes to a value larger than the set value and that the amount of change exceeds the allowable amount
  • the light beam intensity at the time of recording is reduced by the increment ⁇ P Decrease.
  • the judgment result indicates that the light beam intensity at the time of recording changes to a value smaller than the set value and that the amount of change exceeds the allowable amount
  • the light beam intensity at the time of recording is reduced by the increment ⁇ ⁇ increase.
  • the light beam intensity during recording will be increased. Change in If it is within the range that can be handled, the light beam intensity during recording is reduced by the increment ⁇ ⁇ . If the light beam intensity during recording exceeds the range that can be handled, the The pulse interval adjustment amount at the time of recording is changed together with the decreasing operation of the step amount ⁇ P of the light beam intensity (20339).
  • the light beam intensity during recording If the change is within the range that can be dealt with, the light beam intensity during recording is increased by the increment ⁇ P. If the change in the light beam intensity during recording exceeds the range that can be handled, The pulse interval adjustment amount during recording is changed together with the increasing operation of the light beam intensity step size ⁇ P during recording (20339).
  • the time interval for generating the recording condition determination mode is determined by the change in the light beam intensity during recording and the time required for the temperature change on the recording medium to change. For example, in terms of the light beam intensity during recording, set the time within a time interval that does not change more than ⁇ P, which is the maximum change width. Must be kept.
  • the recording information is code-modulated by a modulation circuit 273 so as to match the characteristics of the optical information recording system.
  • the edge-position adjustment circuit 274 and the edge-position adjustment tables 275 and 276 adjust the respective edge positions of the code-modulated recording signal according to the edge interval information immediately before. Is done. Then, the recording signal after the adjustment is input to the laser driver circuit 7, and the laser intensity in the optical pickup 2 is modulated in accordance with the signal i, and information is recorded on the disk 1.
  • the edge position adjustment tables 275 and 276 are used when the recording condition determination mode determines that it is necessary to change the edge adjustment amount, and when the recording linear velocity changes. The contents are changed by the edge position adjustment table switching circuit 278.
  • the modulation circuit 273 and the laser driver circuit 7 may have the same configuration and function as those used in the conventional optical disk device, and detailed descriptions thereof will be omitted.
  • FIG. 29 is a diagram showing a configuration example of the edge interval measurement circuit 270 in FIG.
  • Regeneration binarization i-number 2 7 7 which is the output of binarization circuit 13 Is also input to the impulse signal generation circuit 70 1.
  • This impulse signal generation circuit 70 1 outputs an impulse-like signal waveform at each timing when the polarity of the input signal changes, and this output signal is a signal representing the polarity inversion timing. Then, it is inputted to the recording condition judgment circuit 271, and the AZD converter 72.
  • the reproduced binary signal 277 is also input to an integration circuit 703 composed of an amplifier.
  • this integration circuit 703 has an integration (VH + VL) Z2 level when the "H" level and the "L” level of the reproduced binary signal 7 are VH and VL, respectively.
  • the reference signal 704 is also input.
  • the integration circuit 703 outputs a signal representing the difference between the reproduced binary signal 277 and the integration reference signal, and inputs the signal to the A / D converter 702.
  • the signal power from the controller power is input to the flip-flop 709.
  • a signal indicating the polarity inversion timing is also input to the flip-flop 709 as a clock signal.
  • the output of the flip-flop 709 detects the rising edge of the first reproduced binary signal 277 from the start of the edge interval measurement, and the interval measurement period and analog switch 7 Switch 10 to operate the integration circuit 703.
  • the A / D converter 702 uses the signal representing the timing of the polarity inversion as the timing clock for performing the digital conversion operation, and uses the signal of the integration circuit 703 as a clock. Converts output signal to digital signal. The conversion result is output as a polarity inversion interval signal. And input to the recording condition judgment circuit 27 1.
  • the conversion accuracy of the AZD converter 702 ⁇ has sufficient accuracy as an output value of the pulse interval adjustment amount, and quantization accuracy and the number of bits so that overflow does not occur.
  • the reproduction binarization signal 2777 is an output signal of the binarization circuit 13 and takes "H” or level depending on the presence or absence of the recording mark at the irradiation light spot position on the recording film surface.
  • the reproduced binary signal 277 passes through an impulse signal generation circuit 701, and becomes a signal indicating a polarity inversion timing that generates an impulse waveform at a timing when its polarity changes. Used for trigger signal at 720.
  • the pulse interval of the reproduced binary signal 277 is calculated and output.
  • the integrator circuit 703 is used as the output signal Y (t).
  • Equation 20 is obtained. That is, the output signal Y (t) has its initial value (the output signal level at the time when the edge interval measurement circuit starts operating) Y (0) is 0 according to the operation of the analog switch 710 Therefore, the pulse intervals Pr [1] and Pr [2] of the reproduced signal 402 of FIG. 25 and the gap intervals Gr [1], Gr [2],... Using the integrating circuit The output signal level Vo of 703 is at the time when the polarity of the reproduced binary signal 7 is inverted from "L” to "H".
  • Vo A (-Pr [l] + Gr [l] -Pr [2] + Gr [2] + ...-Pr [i] + Gr [i])
  • Equation 21 shows that the polarity of the reproduced binary signal
  • Vo A (-Pr [1] + Gr [1] -Pr [2] + Gr [2] + ... -Pr [i])
  • a in the above equation is a constant determined by the amplification factor of the integrating circuit 703.
  • the output signal level at this time is obtained by integrating the pulse intervals when the "H" level is represented by a negative value and the "L" level is represented by a positive value for the pulse interval of the reproduced binary signal 277 The results are shown.
  • the AZD converter 702 converts the integrated signal level at that time into a digital value, and inputs the conversion result to the recording condition determination circuit 27 1. That is, the output is given by Eq. 21 and Eq.
  • FIG. 31 shows the recording condition determination circuit 7 11 1 in FIG. It is a structural example.
  • the latch circuits 90 1 and 90 2 and the subtraction circuit 90 3 use the edge interval data expressed by Equation 23 and Equation 24 sent from the edge interval measurement circuit 10 to calculate each B (Pr [i]-Gr [i]).
  • the latch surface 901 is input as a reproduction binary signal 277 7-triggering timing signal, and the edge interval data is sampled and held at the rising edge. ing. That is, at the time of the rise of the reproduced binary signal 277, the data represented by the expression 23 is held and output. In the latch circuit 902, the data is delayed by one trigger.
  • the subtraction circuit 903 subtracts the output of the latch circuit 901 from the output of the latch circuit 903 of the edge interval data, and outputs the result. Since the output of the latch circuit 902 and the output of the latch circuit are the result represented by the equation 23 shifted by one trigger timing, the output of the subtraction circuit 903
  • the addition circuit 904 and the shift register 905 calculate the sum of each B (Pr [i] -Gr [i]) in the repeated data.
  • Shift register 9 0 5 The number of stages is designed to be equal to the number of pulses in one cycle of the recording signal shown in Fig. 25, and an output line is output for each stage and sent to the controller.
  • the reproduction signal 402 is read to the end, the output result at each stage of the shift register is repeated for each i, and B (Pr [i]-G r [i])), the result is used to determine whether the light beam intensity during recording and the temperature of the recording medium have changed based on the criterion shown in Fig. 26. Is examining the power.
  • FIG. 32 is a configuration example of the edge position adjustment circuit 274 and the edge position adjustment table 275 in FIG.
  • the functions C f () and C e () in Equations 18 and 19 are referred to the contents of the edge position adjustment tables 15 and 16 composed of storage elements such as RAM. It is required in the form to do. That is, when obtaining F [i], the first and second parameters in the function C f () are obtained by the address signal line input to the edge position adjustment table 275. Edge which is the conversion result immediately before obtaining the pulse Z gap interval L [i-11], B [i-11], and F [i] of the recording signal 301, which are the elements of the evening. By inputting the amounts representing the position adjustment amounts F [i-l] and E [i-11], the data signal lines output them as their function values.
  • the first and second parameters in the function C e () are determined by the address signal line input to the edge position adjustment table 16.
  • the pulse of the recording signal 301, the Z-gap interval B [i 1), L [ ⁇ ], and an amount representing the edge position adjustment amounts E [i_l], F [i], which are the conversion results immediately before obtaining E [i] are input to the data signal line. Is output as the function value from.
  • the counter surfaces 1001 and 1002 are based on the modulation circuit 273, and the pulse / gear interval of the signal transmitted from the modulation circuit 273 depends on the number of basic clock intervals of the modulated signal. It is detected whether it is hit or not, and it is the address line of the edge position adjustment table.
  • the latch circuits 1003, 1004, 1005, and 1006 are the edge position adjustment table 275 and the timing of the input address signal lines.
  • the shift register circuits 107 and 108 are used to adjust the timing between the modulation signal and the edge position adjustment amount.
  • the selector circuit 100 '09 is a circuit that alternately switches the edge position adjustment amount between the rising side and the falling side, and the programmable delay line circuit 1009 is the edge position. This circuit delays the edge position by the amount of adjustment and adjusts the edge position. Therefore, this output signal is input to the laser driver circuit 7 as the adjusted signal 302.
  • FIG. 33 shows an example of the configuration of the edge position adjusting tape child switching circuit 18 in FIG.
  • This circuit switches the content of the edge position adjustment table according to the change in the recording linear velocity and the temperature of the recording medium, and changes the recording linear velocity and the temperature of the recording medium within the range of use. It is composed of a conversion table data buffer 1102 in which edge position adjustment data for each degree is stored, and a circuit for controlling the switching operation.
  • the table change instruction signal is input from the controller 27 to the counter circuit 1101, and the change of the contents of the edge position adjustment tables 275 and 276 is started.
  • the conversion table data buffer 1102. Is input to determine which edge position adjustment table in the conversion table data buffer 1102 is to be selected. Each edge adjustment amount is transmitted from the conversion table data buffer 1102 for each address number input from the counter circuit 111, and each conversion table is sent.
  • Is stored in the One of the output signals of the counter circuit is used as a table switching signal for selecting one of the edge adjustment amount tables 275 and 276.
  • the remaining signals are used as the conversion table data buffer 1102 and the address signals of the edge position adjustment circuits 275 and 276.
  • the dedicated area used for the recording condition measurement a plurality of locations including the inner circumference side, the outer circumference side, and a space therebetween are used, and the area may be specially provided or a general data recording area. In the latter case, if recorded data already exists in that area, use another free area or temporarily write the information written in that area to use that area. Evacuate to another location such as internal memory.
  • the present invention is a rewritable recording method using heat, the principle of which is any information recording method, and a method of controlling recording conditions such as a recording power and a recording pulse interval applicable to a recording medium.
  • the thermal diffusion effect is high, and it is sensitive to recording conditions, that is, a slight change in recording power, environmental temperature, recording medium configuration, and recording device characteristics, etc., appears as a difference in recording characteristics.
  • this is an indispensable technology for ensuring the reliability of recorded data.
  • this technology is needed to ensure practicality in magneto-optical discs, magneto-optical discs that can be overwritten using exchange coupling force, and optical discs that can use overwrites that can be overwritten. is important.
  • a signal for performing test recording, arithmetically processing the result, and controlling recording is provided.
  • the signal can be controlled to the desired position by the edge position adjustment circuit.
  • this signal recording / reproducing method it is possible to eliminate the variation in the edge position of the reproduced signal due to thermal interference. Also, in order to cope with changes in the light beam intensity during recording and the temperature of the recording medium, optimal recording conditions are always realized, and higher-density recording using mark-length recording. This can be easily achieved without strict adjustments during production, and greatly improves the reliability of recorded data.
  • the present embodiment is a method for realizing high-density recording by changing the recording density depending on the disk position and performing recording.
  • the phase jitter is a phase fluctuation caused by random noise such as noise, laser noise, and amplifier noise of the disk medium in the edge recording described above. And the difference due to the pattern of the recording domain length.
  • the edge shift can be broadly divided into two types: edge shift, where the edge position of the domain changes due to thermal interference during the evening. Due to the good thermal conductivity of a magneto-optical disk medium, it is necessary to use Due to the influence of the recorded pulse, a shift occurs in which the position of the information domain to be recorded next shifts, which is larger than the phase shift. This makes it impossible to reproduce information accurately.
  • the linear density of the magneto-optical disc when it is divided into multiple concentric tracks, ie, zones 1401, 1442, and 1403, is shown.
  • the linear recording density in each zone is the same.
  • Rmin is the radial position of the innermost zone of the magneto-optical disc
  • Ln is the linear density of the nth zone from the inside
  • Ni is the number of sectors at the innermost zone
  • B is the number of data bytes per section.
  • the track pitch is p
  • the number of tracks in the zone is M
  • the data utilization efficiency is 77
  • the capacity of the innermost zone is
  • Equation 27 the linear density can be controlled by the magnitude relationship between B and 27r xM xpx L n X 7 ?. That is, in the present invention Is to improve the line density on the outer circumference rather than on the inner circumference where phase shift occurs.
  • the number of tracks M and the track pitch p are selected so that Ln ⁇ B / (2 ⁇ xMxpX7?) (Equation 28).
  • each sector is increased by one sector / track, the track pitch is set to 1.6 micron, and the recording radius If the circumference is 67.9 mm and the number of innermost sectors is 52, it changes as shown in Fig. 36 depending on the value of M.
  • the shortest pit length of 2-7 modulation is used on the vertical axis. The smaller this is, the higher the line density.
  • the linear density at the recording radius position is increased such that the linear density increases at the outer circumference and decreases at the inner circumference.
  • the contribution of the storage capacity is as shown by the solid line 2100 in FIG. Figure 35 shows the capacity per track obtained by multiplying the linear length by the length of the circumference with respect to the radial position. Integrating this from the radius R i to R 0 gives the total storage capacity.
  • the dotted lines 1 2 0 0 and 2 2 0 0 indicate the case where the linear density is constant, and in comparison with this, as can be seen from FIG. Even if the linear density is reduced, the effect on the total storage capacity is small since the capacity contribution on the inner peripheral side is small.
  • the line density is changed for each of the zones 1401, 1402, and 1403 shown in Fig. 40. There is method power.
  • the amount of phase fluctuation representing the reliability of the data is substantially changed between the inner and outer circumferences. It is possible to reduce the storage capacity.
  • FIG. 1 a schematic diagram showing the cross-sectional structure of the manufactured disk is the same as in FIG.
  • the fabricated disk is made of polycarbonate substrate 5
  • the disks were prepared by the sputter method. Sputtering evening conditions at that time, 1 0 - After evacuated to below 7 Torr, firstly, on the disk substrate 5 0 poly Kabonei bets to form a nitrided Li co down film 5 1. Using pure Si as the target and Ar / N 2 mixed gas as the discharge gas, the input RF power density was 6.6 mWZ cm 2 and the discharge gas pressure was 10 raTorr.
  • a film having a thickness of 75 nm was formed. Subsequently, a TbFeCoNb magneto-optical recording film 52 was formed. RF power input using TbFeCoNb alloy as target and high-purity Ar gas as discharge gas Density: 4.4 mWZcm 2 , Discharge gas pressure: 5 mTorr. The film was formed to a thickness of 30 nm. Again, a silicon nitride film 53 was formed.
  • the input RF power density was 6.6 mW / cm 2 and the discharge gas pressure was 10 mTorr.
  • a film having a thickness of 0 nm was formed.
  • Ni was used in the evening, high-purity Ar gas was used as the discharge gas, and the input RF power density was 3.3 mW / cm 2 and the discharge gas pressure was 15 mTorr. The film was formed to a thickness of 30 nm. Finally, the A1 film 55 is formed. A1 was used as the target, and high-purity Ar gas was used as the discharge gas. The RF power density was 3.3 mW / cm 2 , and the discharge gas pressure was 15 mTorr. Was formed.
  • the film surface of the magneto-optical disk produced in this way is coated with an ultraviolet-curable resin, and two disks are bonded together with an adhesive to form a magneto-optical disk.
  • the structure of the disk used is an example, and the effect of the present invention does not depend on the structure of the disk.
  • this disc has a single-layered recording film, it is also effective for optical discs that can be overwritten using exchange coupling. Needless to say, the method is also effective for optical disk recording control using a phase change.
  • Figure 39 shows a plan view of the disc fabricated in this way.
  • the test pattern 21 shown in FIG. 37 is used to record data in the test track for recording control 1400 shown in FIG. Played the starter.
  • the user data was recorded in the recording area by controlling at least the laser power during recording, the pulse width of recording, or the shape of the recording pulse.
  • Figure 38 shows a schematic diagram of the shape of the recording domain obtained at that time. If recording is performed without control, a tear-shaped magnetic domain is formed, the width is increased because the magnetic domain width is not controlled, or the magnetic domain length is increased or shortened because the magnetic domain length is not controlled. Attempting to do so could result in an error. A major cause of these changes is fluctuations in the operating environment temperature. Therefore, when the disk drive is started or when the disk is inserted, the test pattern is used to record on the recording control test track 1400 and the information is reproduced. The problem was solved by detecting the operating environment temperature and feeding back the results to the setting of the recording conditions, and recording in consideration of the environmental conditions. As a result, the size of the domain recorded on Disk 1 was always constant even when the environmental temperature changed.
  • test drive and the turn stored in the disk drive to the test track provided in the present invention are recorded in advance. By replaying the recorded data overnight and measuring the resulting signal amplitude, we were able to absorb the effects of environmental temperature changes, including variations between disks.
  • control information was collected in detail using the test pattern when the disk drive was started and when the disk was inserted.
  • the recording area of the disk 1 is divided into a plurality of zones 1401, 1402, and 1403 in advance, and the recording is performed for each zone.
  • An area for collecting information for control is set up, and the recording pattern is played back using a test pattern, which results in environmental temperature and variations between media.
  • the recording pattern is played back using a test pattern, which results in environmental temperature and variations between media.
  • test recording has already been performed to prevent deterioration of the test track media, which allows more precise correction. Make sure that test recording is not duplicated in the same location as the previous one, or that test recording is not performed consecutively. However, it is effective to prevent bias in the number of test track rewrites.
  • the force, the first time, and the zones 1404, 1404 can be stored in the storage means, and the recording / reproducing characteristics of the disc in the zone where test recording is not performed can be excluded.

Landscapes

  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Optical Recording Or Reproduction (AREA)
  • Optical Head (AREA)

Abstract

L'invention se rapporte à un appareil à disque optique qui sert à effectuer les opérations d'enregistrement/reproduction/effacement des signaux numériques d'un système d'enregistrement de longueur de repère sur un support d'enregistrement optique tel qu'un disque optique, et qui utilise des moyens pour éliminer les fluctuations d'une position de bord dues aux interférences thermiques entre les creux, ainsi que des moyens pour réduire les fluctuations de la position du bord qui résultent d'un changement des conditions environnantes extérieures. A cet effet, la présente invention propose des moyens notamment: (1) pour régler le profil d'une forme d'onde des impulsions d'enregistrement; (2) pour faire varier la densité d'enregistrement du disque en fonction de la position du disque; et (3) pour effectuer un enregistrement test avant d'enregistrer les données d'utilisateur. Ainsi, on peut obtenir un enregistrement optique de très grande densité.
PCT/JP1992/001460 1990-06-29 1992-11-10 Appareil a disque magneto-optique et support d'enregistrement WO1993010527A1 (fr)

Priority Applications (3)

Application Number Priority Date Filing Date Title
DE4293957T DE4293957T1 (de) 1991-11-11 1992-11-10 Magnetooptischer Plattenspeicher und magnetooptisches Aufzeichnungsmedium
US08/087,777 US5642343A (en) 1990-06-29 1992-11-10 Magnetooptic disc apparatus and recording medium
DE4293957A DE4293957C2 (de) 1991-11-11 1992-11-10 Optische Plattenspeichereinrichtung und Verfahren für die Aufzeichnung und Wiedergabe von optischer Information

Applications Claiming Priority (11)

Application Number Priority Date Filing Date Title
US72070691A 1991-06-25 1991-06-25
JP3294145A JP3063314B2 (ja) 1991-11-11 1991-11-11 ディジタル信号記録再生方法及び装置
JP3/294145 1991-11-11
JP4/26511 1992-02-13
JP2650992 1992-02-13
JP2650892 1992-02-13
JP4/26509 1992-02-13
JP2651192 1992-02-13
JP4/26508 1992-02-13
JP4/100897 1992-04-21
JP4100897A JPH05298737A (ja) 1992-04-21 1992-04-21 情報の記録再生制御方法

Publications (1)

Publication Number Publication Date
WO1993010527A1 true WO1993010527A1 (fr) 1993-05-27

Family

ID=27549295

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP1992/001460 WO1993010527A1 (fr) 1990-06-29 1992-11-10 Appareil a disque magneto-optique et support d'enregistrement

Country Status (1)

Country Link
WO (1) WO1993010527A1 (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1997006530A1 (fr) 1995-08-09 1997-02-20 Hitachi, Ltd. Dispositif de disque optique
WO2000028535A1 (fr) * 1998-11-06 2000-05-18 Matsushita Electric Industrial Co., Ltd. Procede et dispositif de recherche de conditions sur une impulsion d'enregistrement de disque optique
EP1058240A3 (fr) * 1999-06-03 2002-01-23 Samsung Electronics Co., Ltd. Procédé de génération de signaux de commande pour impulsions d'écriture pour supports d'enregistrement optique et appareil d'enregistrement utilisant ce procédé
CN110864711A (zh) * 2018-08-27 2020-03-06 台达电子工业股份有限公司 编码器及其位置检测方法

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JPS59223955A (ja) * 1983-05-20 1984-12-15 トムソン−セエスエフ 光学基板に照射される集束ビームの較正方法及び装置
JPS6040570A (ja) * 1983-08-12 1985-03-02 Hitachi Ltd デ−タ記録再生装置
JPS63244330A (ja) * 1987-03-30 1988-10-11 Nikon Corp 光デイスク装置
JPH027232A (ja) * 1987-12-01 1990-01-11 Matsushita Electric Ind Co Ltd 光学的情報記録再生装置
JPH0261834A (ja) * 1988-08-25 1990-03-01 Fujitsu Ltd 光ディスク装置
JPH02252141A (ja) * 1989-03-27 1990-10-09 Canon Inc 光学的情報記録再生装置
JPH03102656A (ja) * 1989-09-14 1991-04-30 Asaka Co Ltd マルチビーム光ディスク装置

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS59223955A (ja) * 1983-05-20 1984-12-15 トムソン−セエスエフ 光学基板に照射される集束ビームの較正方法及び装置
JPS6040570A (ja) * 1983-08-12 1985-03-02 Hitachi Ltd デ−タ記録再生装置
JPS63244330A (ja) * 1987-03-30 1988-10-11 Nikon Corp 光デイスク装置
JPH027232A (ja) * 1987-12-01 1990-01-11 Matsushita Electric Ind Co Ltd 光学的情報記録再生装置
JPH0261834A (ja) * 1988-08-25 1990-03-01 Fujitsu Ltd 光ディスク装置
JPH02252141A (ja) * 1989-03-27 1990-10-09 Canon Inc 光学的情報記録再生装置
JPH03102656A (ja) * 1989-09-14 1991-04-30 Asaka Co Ltd マルチビーム光ディスク装置

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1997006530A1 (fr) 1995-08-09 1997-02-20 Hitachi, Ltd. Dispositif de disque optique
EP0844609A1 (fr) * 1995-08-09 1998-05-27 Hitachi, Ltd. Dispositif de disque optique
EP0844609A4 (fr) * 1995-08-09 2007-10-17 Hitachi Ltd Dispositif de disque optique
WO2000028535A1 (fr) * 1998-11-06 2000-05-18 Matsushita Electric Industrial Co., Ltd. Procede et dispositif de recherche de conditions sur une impulsion d'enregistrement de disque optique
US6791926B1 (en) 1998-11-06 2004-09-14 Matsushita Electric Industrial Co., Ltd. Method and device for finding conditions on recording pulse of optical disk
US7236438B2 (en) 1998-11-06 2007-06-26 Matsushita Electric Industrial Co., Ltd. Method and apparatus for determining recording pulse parameters for an optical disc
US7248552B2 (en) 1998-11-06 2007-07-24 Matsushita Electric Industrial Co., Ltd. Method and apparatus for determining recording pulse parameters for an optical disc
EP1058240A3 (fr) * 1999-06-03 2002-01-23 Samsung Electronics Co., Ltd. Procédé de génération de signaux de commande pour impulsions d'écriture pour supports d'enregistrement optique et appareil d'enregistrement utilisant ce procédé
US6762986B1 (en) 1999-06-03 2004-07-13 Samsung Electronics Co., Ltd. Method of generating write pulse control signals for various types of optical recording media and recording apparatus adopting the same
CN110864711A (zh) * 2018-08-27 2020-03-06 台达电子工业股份有限公司 编码器及其位置检测方法
CN110864711B (zh) * 2018-08-27 2022-03-11 台达电子工业股份有限公司 编码器及其位置检测方法

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