WO2004012186A1 - ディスク再生装置 - Google Patents
ディスク再生装置 Download PDFInfo
- Publication number
- WO2004012186A1 WO2004012186A1 PCT/JP2003/009507 JP0309507W WO2004012186A1 WO 2004012186 A1 WO2004012186 A1 WO 2004012186A1 JP 0309507 W JP0309507 W JP 0309507W WO 2004012186 A1 WO2004012186 A1 WO 2004012186A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- power
- value
- reproduction
- signal
- disk
- Prior art date
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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
- G11B7/1267—Power calibration
Definitions
- the present invention relates to a disk reproducing apparatus that irradiates a disk with laser light from an optical head and reproduces a signal from the disk.
- the meandering (opple) is performed as shown in the figure.
- the meandering frequency is FM-modulated at a predetermined center frequency.
- the signal is detected by the signal reproduction, and the signal is always detected.
- the linear velocity constant control is realized by adjusting the rotation of the magneto-optical disk so as to have the center frequency.
- the pop signal is FM-modulated as described above, and contains various information such as address information (wobble information). At the time of signal reproduction, various control operations are carried out based on the wobble information. Will be revealed.
- a disk recording / reproducing apparatus of a laser pulse magnetic field modulation type when reproducing a signal, the magneto-optical disk is irradiated with laser light, and when recording a signal, the magneto-optical disk is irradiated with laser light.
- the disk is locally heated.
- the laser power at the time of signal reproduction is reduced.
- the signal reading starts when the temperature of the beam spot area reaches a predetermined value.
- the laser power (reproduction power) during signal reproduction is the laser power (recording power) during signal recording. ), So that there is no danger that the recorded signal will be damaged during signal reproduction.
- the laser power at the time of signal reproduction is set between two boundary values at which the error rate is a specified value or a value close to the specified value, that is, between the lower boundary reproduction power Prmin and the upper boundary reproduction power Prmax, It is necessary to set the laser power at the time of signal recording to two boundary values at which the error rate is at or near a specified value, that is, between the lower boundary recording power and the upper boundary recording power.
- the optimum reproducing power and recording power that minimize the error rate are searched.
- the optimum reproduction power P is obtained by changing the lower boundary value Prmin to the following value, and then adding a predetermined value N (power for a predetermined step) to the reproduction power.
- FIG. 10 shows a reproducing power adjustment procedure executed when the disk recording / reproducing apparatus is started.
- an initial value P is set as the current reproduction power Pr. Is set, and in step S52, the test track is played back.
- step S53 the process proceeds to step S55, in which the reproduction power Pr is increased by one step, and then the test track is reproduced in step S56. And measure the error rate ⁇ 'at that time.
- step S57 the measured error rate E ′ is equal to the specified value ⁇ . It is determined whether or not the following conditions are satisfied. If the determination is no, the process returns to step S55 to repeat the same procedure.
- step S 5 7 If the error rate E 'is determined YES at step S 5 7 becomes a specified value E 0 below, the process proceeds to step S 5 8, the reproduction power Pr at that time the lower boundary value [rho rmin, Further, in step S59, the procedure is terminated with the value obtained by adding the power for four steps to the lower boundary reproduction power Prmin as the optimum reproduction power Prcent. As a result, signal reproduction is started with the optimum laser power.
- the optimization of the laser power is executed every time the temperature of the disk changes more than a predetermined temperature.
- the reproduction power Pr is set to the current set value, and in step S62, the test track is reproduced, and the error rate E at that time is measured.
- step S63 the process proceeds to step S65, in which the reproduction power Pr is increased by one step, and then the test track is reproduced in step S66. And measure the error rate at that time.
- step S67 the measured error rate E 'is the specified value ⁇ . It is determined whether the following conditions are satisfied. If the determination is no, the process returns to step S65 and the same procedure is repeated.
- Error rate E ' is the specified value ⁇ . If the answer is YES in step S67, the process proceeds to step S68, in which the reproduction power Pr at that time is set to the lower boundary value ⁇ rmin, and in step S69, the lower power is set to the lower boundary value.
- the value obtained by adding the power for four steps to the reproduction power Prmin is set as the optimum reproduction power Prcent, and the procedure ends. As a result, the reproduction and recording of the signal are continued with the optimum laser power according to the temperature of the magneto-optical disk.
- the reproducing power used as a reference when searching for the lower boundary value Prmin in optimizing the reproducing power during normal operation that is, the reproducing power set at that time and the reproducing power ⁇ is, because it is far value from the new lower boundary value Prtnin 2, a long time is required to search for a new lower boundary value Prmin 2, it takes time to find the optimum reproduction power, Original playback behavior There was a problem that hindered writing and recording operations.
- An object of the present invention is to provide a disk reproducing apparatus capable of finding an optimum laser power in a short time during a normal operation. Disclosure of the invention
- a disc reproducing apparatus includes a laser drive circuit capable of supplying a drive signal to an optical head and adjusting the power of laser light emitted from the optical head, and an operation of the laser drive circuit. And a control circuit for controlling the control circuit.
- the control circuit includes a reproduction power optimizing means for repeating a process of optimizing the power of the laser light at the time of signal reproduction.
- the reproducing power optimizing means includes:
- Evaluation data detection means for detecting evaluation data indicating the quality of the signal reproduction state; and search means for searching one of the two boundary values of the reproduction path at which the evaluation data has a specified value or a value in the vicinity thereof.
- Optimum reproduction power calculation means for calculating the optimum reproduction power based on one of the searched boundary values
- the search means searches for a new boundary value based on the boundary value obtained in the previous optimization process.
- the frequency of occurrence of bit errors (bit error rate) included in the reproduced signal can be adopted.
- a new boundary value is searched based on the boundary value searched in the previous optimization processing.
- the boundary value searched in the previous optimization process is a value closer to the new boundary value than the reproduction power set at that time. Therefore, the time required for searching for the boundary value is reduced, and the time required for calculating the optimum reproduction power is reduced.
- the search means searches a lower boundary value of the smaller one of the two boundary values, and the optimum reproduction power calculation means adds a predetermined value to the lower boundary value.
- the optimum reproduction power is determined.
- the relationship between the reproduction power and the error rate can be represented by a quadratic curve as described above, and the laser power corresponding to the apex of the quadratic curve is the optimum reproduction power for minimizing the error rate.
- the optimum value of the reproducing power changes, the lower boundary value also changes, and the difference between the optimum value and the lower boundary value becomes a substantially constant value. Therefore, if the lower boundary value is obtained, the optimum reproduction power can be obtained by adding this difference to the lower boundary value.
- a temperature detecting means for detecting the temperature of the disk is provided, and the reproducing power optimizing step executes optimization of the reproducing power every time the temperature of the disk changes by a predetermined temperature.
- the optimum reproducing power corresponding to the temperature of the disk is obtained, and the power of the laser light emitted from the optical head becomes the optimum value. Adjusted. As a result, the bit error rate at the time of signal reproduction is minimized, and there is no possibility that the recorded signal is damaged by the signal reproduction.
- the optimum laser power can be obtained in a short time during normal operation.
- FIG. 1 is a block diagram showing a configuration of a disk recording / reproducing apparatus according to the present invention.
- FIG. 2 is a flowchart showing a procedure executed when the disk recording / reproducing apparatus is started.
- FIG. 3 is a flowchart showing a specific procedure of the reproduction power adjustment processing executed at the time of startup.
- FIG. 4 is a flowchart showing a procedure executed during the normal operation of the disc recording / reproducing apparatus.
- FIG. 5 shows the specific procedure of the reproduction power adjustment processing executed during normal operation. It is a flow chart.
- FIG. 6 is a graph illustrating a procedure of a reproduction power adjustment process executed when the disk recording / reproduction device is started.
- FIG. 7 is a graph illustrating a procedure of a reproduction power adjustment process performed during a normal operation of the disk recording / reproduction device.
- FIG. 8 is an enlarged perspective view showing lands and groups formed on the magneto-optical disk.
- FIG. 9 is a graph showing the relationship between the reproduction power and the error rate.
- FIG. 10 is a flowchart showing a specific procedure of a reproduction power adjustment process executed at startup in a conventional disk recording / reproduction device.
- FIG. 11 is a flowchart showing a specific procedure of a reproduction power adjustment process executed during normal operation in the disk recording / reproducing apparatus.
- FIG. 12 is a flowchart illustrating a procedure of a reproduction power adjustment process executed when the disk recording / reproduction device is started.
- FIG. 13 is a graph illustrating a procedure of a reproduction power adjustment process performed during a normal operation of the disc recording / reproducing apparatus.
- a magnetic head (3) and an optical head are vertically arranged with a magneto-optical disk (1) rotated by a spindle motor (2) therebetween.
- a magnetic head drive circuit (4) is connected to the magnetic head (3), and a laser drive circuit (6) is connected to the optical head (5).
- a control circuit (7) is connected to the magnetic head drive circuit (4) and the laser drive circuit (6), and the control circuit (7) controls the signal recording / reproducing operation.
- optics The output signal of the head (5) is supplied to a control circuit (7), where it is subjected to processing such as amplification, detection of a reproduction signal, and error correction, and then output to a subsequent circuit as reproduction data.
- a servo circuit (9) is connected to the spindle motor (2) and the optical head (5).
- the focus error (FE) signal and the tracking error (TE) signal obtained from the output signal of the optical head (5) are supplied from the control circuit (7) to the servo circuit (9), and the FE signal and the TE signal Based on the above, focus servo and tracking servo for an actuator (not shown) mounted on the optical head (5) are executed.
- An external synchronization signal is supplied from the control circuit (7) to the servo circuit (9), and the rotation of the spindle motor (2) is controlled based on the signal.
- a temperature sensor (8) for measuring the temperature of the magneto-optical disk (1) is installed opposite to the magneto-optical disk (1), and an output terminal of the temperature sensor (8) is connected to a control circuit (7). It is connected to the.
- a laser power control signal is created based on the temperature data obtained from the temperature sensor (8), and the created signal is supplied to the laser drive circuit (6).
- the power of the laser light emitted from the optical head (5) during signal reproduction and signal recording is adjusted according to the laser power control signal as described later.
- FIG. 2 shows a procedure executed by the control circuit (7) when the disk recording / playback apparatus is started.
- step S1 various gains of the servo circuit (9) are set to initial values, and in step S2, the focus offset value is adjusted based on the TE signal. Do.
- step S3 the tracking offset value is adjusted based on the TE signal, and then in step S4, the recording power and the reproduction power are set to initial values, respectively.
- step S6 the focus offset value is adjusted based on the RF signal.
- the reproducing power is adjusted in step S7.
- step S8 the address gain and the FCM gain are adjusted in step S9.
- the series of adjustment processes in steps S6 to S9 are executed for each of the lands and groups of the test tracks provided in advance on the magneto-optical disk.
- step S10 the recording power is adjusted for each of the lands and groups of the test track, and in step S11, the current values of the parameters adjusted as described above are checked. After storing the current values of those parameters in the internal memory in step S12, the current disk temperature T. is stored in the internal memory in step S13, and the procedure is terminated.
- the reproduction power is set to an initial value P.
- FIG. 3 shows a specific procedure of the reproduction power adjustment processing executed in step S7.
- an initial value P is set as the current reproduction power Pr. Is set, and in step S22, the test track is reproduced, and the error rate E at that time is measured.
- the process proceeds to Step S 2 4 After lowering the reproduction power Pr by 4 steps, return to step S22 and repeat the same procedure.
- step S23 the error value is the specified value E. If the answer is yes in step S23, the process proceeds to step S25, and the reproduction power Pr is increased by one step. After that, in step S26, the test track is reproduced, and the error rate at that time is measured. Next, in step S27, the measured error rate E 'is the specified value ⁇ . It is determined whether or not the following conditions are satisfied. If the determination is no, the process returns to step S25 and the same procedure is repeated.
- step S27 the process proceeds to step S28, where the reproduction power Pr at that time is set to the lower boundary value ⁇ rmin, and in step S29, the lower boundary value Prmin is set to After storing the data in the internal memory, in step S30, the value obtained by adding the power for the four steps to the lower boundary reproduction power Prmin is set as the optimum reproduction power Prcent, and the procedure is terminated. As a result, reproduction and recording of the signal are started with the optimum laser power.
- FIG. 4 shows a procedure executed by the control circuit (7) in the normal operation for signal reproduction and signal recording after the system is started.
- the normal operation is started, first, in step S31, the past disk temperature T is set. ld is the temperature T stored in the built-in memory when the device itself is started as described above.
- the current disk temperature Tn is set . Measure w .
- step S33 the current disk temperature T n is set .
- w is the past disk temperature T. ld to determine whether a predetermined temperature T thr adding to the resulting temperature (T. ld + T thr) above, the process returns to step S 32 if the answer is negative, Ri Repetitive the same procedure return.
- the predetermined temperature T thr is set to, for example, 5 ° C.
- step S34 the apparatus main body changes various parameters according to the disc temperature change. It is determined whether or not the adjustment is possible. If the determination is no, the process returns to step S32, while if the determination is yes, the process proceeds to step S35 to adjust the reproduction power. After the adjustment, the recording power is adjusted in step S36.
- step S37 the focus offset value is adjusted based on the RF signal.
- step S38 the focus offset value is adjusted based on the TE signal.
- step S39 the current value of the parameter adjusted as described above is stored in the built-in memory, and in step S40, the past disk temperature T is obtained. ld the current disk temperature T n . Set to w and return to step S32.
- the reproduction power adjustment processing in step S35 as shown in FIG. 7, first, the reproduction power is reduced from the lower boundary value Prmin obtained in the previous adjustment processing, so that the reproduction power is adjusted to the error rate at that time.
- FIG. 5 shows a specific procedure of the reproduction power adjustment processing executed in step S35.
- step S41 the lower boundary value Prmin stored in the internal memory is set as the reproduction power Pr, and in step S42, the test track is reproduced, and the error rate at that time is set. Measure E.
- Step S 4 7 If the error rate E 'is determined YES at Step S 4 7 becomes a specified value E 0 less, the process proceeds to Step S 4 8, and the reproduction power Pr at that time the lower boundary value [rho Rrain, Finally, in step S49, the lower boundary value Prmin is stored in the built-in memory, and in step S50, the lower boundary reproduction power Prmin is converted to the power for four steps. The procedure is terminated with the value obtained by adding 1 as the optimum reproduction power Prcent. As a result, reproduction and recording of signals are continued with the optimum laser power according to the temperature of the magneto-optical disk.
- the lower boundary value Prmin obtained in the previous adjustment processing is used as a reference.
- a new lower boundary value Prrain 2 is retrieved.
- the previous value Pr mini closer to the new lower boundary value P rmin 2 than the playback power P i set at that time is used as a reference. Therefore, the time required to search for the lower boundary value is reduced. As a result, the time required to calculate the optimum reproduction power is reduced, and there is no possibility that the original reproduction operation and recording operation will be affected.
- a configuration is employed in which the reproduction power at which the error rate is equal to or less than the specified value is searched for as the lower boundary reproduction power Prrain. It is also possible to adopt a configuration for searching as a part.
Abstract
Description
Claims
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US10/520,280 US20060007824A1 (en) | 2002-07-30 | 2003-07-25 | Disc reproduction device |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2002-220865 | 2002-07-30 | ||
JP2002220865A JP2004063011A (ja) | 2002-07-30 | 2002-07-30 | ディスク再生装置 |
Publications (1)
Publication Number | Publication Date |
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WO2004012186A1 true WO2004012186A1 (ja) | 2004-02-05 |
Family
ID=31184824
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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PCT/JP2003/009507 WO2004012186A1 (ja) | 2002-07-30 | 2003-07-25 | ディスク再生装置 |
Country Status (3)
Country | Link |
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US (1) | US20060007824A1 (ja) |
JP (1) | JP2004063011A (ja) |
WO (1) | WO2004012186A1 (ja) |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
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FR2950727B1 (fr) * | 2009-09-29 | 2012-02-17 | Commissariat Energie Atomique | Lecteur de disque optique en super-resolution et procede de lecture optimisee par mesure de reflectivite |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH08221760A (ja) * | 1995-02-17 | 1996-08-30 | Fujitsu Ltd | 光ディスク装置及び光記録媒体の記録再生方法 |
JPH1153781A (ja) * | 1997-08-04 | 1999-02-26 | Sharp Corp | 光記憶装置における再生光量制御装置および光記録媒体 |
Family Cites Families (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6392970B1 (en) * | 1997-08-04 | 2002-05-21 | Sharp Kabushiki Kaisha | Reproducing light quantity control method for optical memory device, and reproducing light quantity control device, and optical recording medium |
JP2001202666A (ja) * | 2000-01-18 | 2001-07-27 | Canon Inc | 再生パワーテスト方法及び光学的情報再生装置 |
JP3787316B2 (ja) * | 2002-04-26 | 2006-06-21 | キヤノン株式会社 | 光磁気記録再生装置 |
-
2002
- 2002-07-30 JP JP2002220865A patent/JP2004063011A/ja active Pending
-
2003
- 2003-07-25 US US10/520,280 patent/US20060007824A1/en not_active Abandoned
- 2003-07-25 WO PCT/JP2003/009507 patent/WO2004012186A1/ja active Application Filing
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH08221760A (ja) * | 1995-02-17 | 1996-08-30 | Fujitsu Ltd | 光ディスク装置及び光記録媒体の記録再生方法 |
JPH1153781A (ja) * | 1997-08-04 | 1999-02-26 | Sharp Corp | 光記憶装置における再生光量制御装置および光記録媒体 |
Also Published As
Publication number | Publication date |
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JP2004063011A (ja) | 2004-02-26 |
US20060007824A1 (en) | 2006-01-12 |
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