WO2007148669A1 - 光記録再生方法およびシステム、ならびにプログラム - Google Patents
光記録再生方法およびシステム、ならびにプログラム Download PDFInfo
- Publication number
- WO2007148669A1 WO2007148669A1 PCT/JP2007/062269 JP2007062269W WO2007148669A1 WO 2007148669 A1 WO2007148669 A1 WO 2007148669A1 JP 2007062269 W JP2007062269 W JP 2007062269W WO 2007148669 A1 WO2007148669 A1 WO 2007148669A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- light
- recording
- unit
- signal
- reproduction
- Prior art date
Links
- 230000003287 optical effect Effects 0.000 title claims description 75
- 238000000034 method Methods 0.000 title claims description 74
- 230000008569 process Effects 0.000 claims description 63
- 238000002834 transmittance Methods 0.000 claims description 36
- 230000008859 change Effects 0.000 claims description 32
- 230000010287 polarization Effects 0.000 claims description 9
- 238000012544 monitoring process Methods 0.000 claims description 3
- 238000012545 processing Methods 0.000 description 65
- 230000006870 function Effects 0.000 description 27
- 230000009467 reduction Effects 0.000 description 23
- 238000012937 correction Methods 0.000 description 18
- 230000004048 modification Effects 0.000 description 11
- 238000012986 modification Methods 0.000 description 11
- 238000010586 diagram Methods 0.000 description 9
- 230000000630 rising effect Effects 0.000 description 8
- 239000010410 layer Substances 0.000 description 7
- 239000011241 protective layer Substances 0.000 description 5
- 230000006866 deterioration Effects 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 238000001514 detection method Methods 0.000 description 3
- 239000004973 liquid crystal related substance Substances 0.000 description 3
- 238000012546 transfer Methods 0.000 description 3
- 230000005855 radiation Effects 0.000 description 2
- 230000004044 response Effects 0.000 description 2
- 102220040592 rs587778386 Human genes 0.000 description 2
- 238000005070 sampling Methods 0.000 description 2
- 238000013459 approach Methods 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 230000001427 coherent effect Effects 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 238000011157 data evaluation Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000004193 electrokinetic chromatography Methods 0.000 description 1
- 230000001678 irradiating effect Effects 0.000 description 1
- 230000007935 neutral effect Effects 0.000 description 1
- 230000010355 oscillation Effects 0.000 description 1
- 230000008929 regeneration Effects 0.000 description 1
- 238000011069 regeneration method Methods 0.000 description 1
- 239000002356 single layer Substances 0.000 description 1
- 230000007480 spreading Effects 0.000 description 1
- 230000001360 synchronised effect Effects 0.000 description 1
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
- G11B7/135—Means for guiding the beam from the source to the record carrier or from the record carrier to the detector
- G11B7/1365—Separate or integrated refractive elements, e.g. wave plates
- G11B7/1369—Active plates, e.g. liquid crystal panels or electrostrictive elements
-
- 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
- G11B7/005—Reproducing
-
- 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
- G11B7/1263—Power control during transducing, e.g. by monitoring
Definitions
- the present invention relates to an optical recording / reproducing method and system for reproducing data optically recorded on a recording medium such as a CD, a DVD, a Blu-ray DISC, and an HD (High Definition) DVD, and a program.
- a recording medium such as a CD, a DVD, a Blu-ray DISC, and an HD (High Definition) DVD
- Recording media such as CDs, DVDs, and next-generation DVDs (Blu-ray DISCs, HD DVDs) are irradiated with laser light, and the state of the media recording layer changes based on the heat caused by the irradiated laser light
- a plurality of recording marks also called recording pits
- the linear velocity (speed of the laser beam traveling on the medium 3 during recording and Z or reproduction) is increased (for example, changing from 1 ⁇ to 2 ⁇ , 32 ⁇ speed, etc.) This makes it possible to shorten playback and Z or recording speed and time.
- a single mode laser (laser having a single longitudinal mode) having a relatively small operating current is used as a light source.
- the laser light emitted from this single mode laser is very coherent, so noise that causes fluctuations in the laser light power of the laser light emitted from the light source (single mode laser) when reproducing data.
- the noise that causes the laser light power fluctuation includes noise (return light noise) caused by interference with the return light from the recording medium, optical components, and the like, and laser noise caused by temperature fluctuation and the like.
- Patent Documents 1 and 2 describe the optical coupling efficiency, which is the ratio of the amount of laser light focused on the recording medium to the total amount of laser light emitted from the light source, in its mode (recording). (Mode Z playback mode), by changing according to the type of recording medium and Z or its recording layer (multilayer Z single layer), it is possible to maintain a high CNR while suppressing the irradiation laser light power,
- the optical coupling efficiency which is the ratio of the amount of laser light focused on the recording medium to the total amount of laser light emitted from the light source, in its mode (recording).
- Mode Z playback mode by changing according to the type of recording medium and Z or its recording layer (multilayer Z single layer), it is possible to maintain a high CNR while suppressing the irradiation laser light power.
- Patent Document 1 JP 2002-260272 A
- Patent Document 2 Japanese Patent Laid-Open No. 2003-196880
- Patent Document 3 Japanese Patent Laid-Open No. 2005-346823
- FIG. 1 is a diagram showing an example of a relationship between a recording signal written on a part of a recording track and a laser beam output waveform obtained by high-frequency superposition.
- the run length (mark length) along the recording track of the recording signal is a modulated force.
- the recording signal having the shortest run length is recorded on the recording track. It is assumed that it is written in part. Also, show a state where a part of the recording track is unfolded in a straight line along the track direction! / Speak.
- an intermittent high-frequency current having a positive duty (on-duty) in a sine wave of less than 50% is used as the high-frequency current.
- the present invention has been made in view of the above-described circumstances. Even when the reproduction linear velocity is increased, the recorded signal recorded on the recording medium is surely read and the corresponding data is read. Its purpose is to make it possible to play
- a recording signal written on a recording track of a recording medium is modulated by a drive signal on which a frequency signal is superimposed, and is recorded on the recording track at a predetermined scanning speed.
- This is an optical recording / reproducing system that reads and reproduces data by light scanned along.
- the optical recording / reproducing system includes a superposition amount control unit that controls the superposition amount of the frequency signal with respect to the drive signal in accordance with the scanning speed.
- a recording signal periodically written on a recording track of a recording medium is modulated by a drive signal on which a frequency signal is superimposed, and the recording track is scanned at a predetermined scanning speed.
- a program readable by a computer provided in an optical recording / reproducing system that reads and reproduces data as light scanned along the line. This program causes the computer to execute a process of controlling a superposition amount of the frequency signal with respect to the drive signal in accordance with the scanning speed.
- a recording signal periodically written on a recording track of a recording medium is modulated by a drive signal on which a frequency signal is superimposed, and the recording track is scanned at a predetermined scanning speed.
- This optical recording / reproducing method in which data is read by light scanned along the line and reproduced as data.
- This optical recording / reproducing method includes a step of controlling a superposition amount of the frequency signal with respect to the drive signal in accordance with the scanning speed.
- FIG. 1 is a diagram showing an example of the relationship between a plurality of recording marks written on a part of a recording track and a laser beam output waveform obtained by high-frequency superposition.
- FIG. 2 is a block diagram showing a schematic configuration of the data recording / reproducing system according to the first embodiment of the present invention.
- FIG. 3 is a flowchart schematically showing an example of processing executed by the computer of the data recording / reproducing system according to the first embodiment of the present invention.
- FIG. 4 The two intermittent high-frequency currents superimposed on the drive current from the APC circuit shown in FIG. 2 by the processing from step SI to step S4 in FIG. Figure showing the relationship with the laser beam output from the LD unit shown in
- FIG. 5 is a flowchart schematically showing an example of processing executed by the computer of the data recording / reproducing system according to the second embodiment of the present invention.
- FIG. 6 The Blu-ray DISC is used as the recording medium shown in FIG. 2, and the data recorded on the Blu-ray DISC using the processing of steps S10 to S16 shown in FIG. A graph showing an example of a relationship between a change in playback speed and a change in error rate when playback is performed while changing.
- FIG. 7 is a flowchart schematically showing an example of processing executed by a computer of the data recording / reproducing system according to the third embodiment of the present invention.
- FIG. 8 is a flowchart schematically showing an example of processing executed by the computer of the data recording / reproducing system according to the fourth embodiment of the present invention.
- FIG. 10 is a flowchart schematically showing an example of processing executed by the computer of the data recording / reproducing system according to the fifth embodiment of the present invention.
- FIG. 11 A diagram corresponding to the two intermittent high-frequency currents superimposed on the drive current from the APC circuit shown in FIG. 9 and the respective intermittent high-frequency currents by the processing of step S40 to step S42 in FIG.
- FIG. 9 is a diagram showing the relationship with the laser beam output from the LD unit shown in FIG.
- FIG. 12 is a flowchart schematically showing an example of processing executed by the computer of the data recording / reproducing system according to the sixth embodiment of the present invention.
- FIG. 13 The Blu-ray DISC is used as the recording medium shown in FIG. 9 and the data recorded on the Blu-ray DISC using the processing of steps S50 to S53 shown in FIG. A graph showing an example of the relationship between a change in playback speed and a change in error rate when playback is performed while changing the speed.
- FIG. 14 is a flowchart schematically showing an example of processing executed by a computer of the data recording / reproducing system according to the seventh embodiment of the present invention.
- FIG. 15 is a flowchart schematically showing an example of processing executed by the computer of the data recording / reproducing system according to the eighth embodiment of the present invention.
- FIG. 2 is a block diagram showing a schematic configuration of the data recording / reproducing system 1 according to the first embodiment of the present invention.
- reference numeral 3 denotes a recording medium having, for example, a disk-shaped protective layer and a disk-shaped recording layer that includes a recording track formed in a snoral shape or a concentric shape and is laminated on the protective layer. It is.
- the recording medium 3 can be a CD, DVD, Blu-ray Disc, HD DVD or the like.
- the data recording / reproducing system 1 includes a function for recording information on a recording track of the recording medium 3 that rotates at a desired speed, and a recording on the recording track of the recording medium 3.
- the apparatus has a function of reproducing the recorded information.
- the recording track has at least one of lands and groups alternately arranged along the radial direction as one configuration example. At least one of them is meandered at a predetermined frequency, and a part thereof is phase-modulated, for example, so that information such as address information of the recording track is included in the modulation portion.
- the data recording / reproducing system 1 includes an optical pickup unit (optical head unit) 5 for recording and / or reproducing information by spot-irradiating light onto a recording track of a rotating recording medium 3. And a power adjusting unit 7 for adjusting the uniformity of the light irradiated on the recording medium 3 on the recording medium 3.
- optical pickup unit optical head unit
- power adjusting unit 7 for adjusting the uniformity of the light irradiated on the recording medium 3 on the recording medium 3.
- the data recording / reproducing system 1 includes a rotational speed control of the recording medium 3 and an optical pickup unit.
- Servo driver 9 as a servo control system for controlling the focus position of the spot light irradiated onto the recording track of the recording medium 3 and tracking control (tracking control) of the spot light with respect to the recording track.
- the data recording / reproducing system 1 includes a function for generating data corresponding to information to be recorded on the recording medium 3 (hereinafter referred to as recording data), and a recording medium obtained by the optical pickup unit 5.
- a recording / playback data processing unit 11 having a function of generating data corresponding to the information recorded in 3 (hereinafter referred to as playback data) is provided.
- the data recording / reproducing system 1 includes an optical pickup unit 5, a power adjusting unit 7, a servo driver 9, and a computer 13 for controlling the recording / reproducing data processing unit 11.
- the computer 13 is a first memory 13a such as an HDD (Hard Disk Drive), FLASH MEMORY or the like for storing data representing processing results and the like, and a main memory of the computer 13, such as a first memory. And a second memory 13b holding a plurality of programs P loaded from 13a.
- the plurality of programs P are programs that cause the computer 13 to execute the control operation.
- the optical pickup unit 5 drives a laser diode (LD) unit 15 that emits laser light as information recording and Z or reproduction light, and drives and controls the LD unit 15.
- the LD driver 17 that controls the output waveform of the laser light output from the LD unit 15 and the LC (Light Control) described later as an element for adjusting the amount of laser light output from the LD unit 15
- It has a light control element 19 that is also configured with a liquid crystal element force in which the light transmittance is changed by a change in applied voltage from the driver.
- the LD unit 15 and the light amount adjusting element 19 in the optical pickup unit 5 are such that the optical axis of the laser light guided through both elements is substantially parallel to the protective layer surface of the recording medium 3. It is arranged to become.
- the light amount adjusting element 19 has a light transmittance of about 100% (attenuation rate is about 0%) in the initial state (non-voltage application state).
- the optical pickup unit 5 is output from the LD unit 15 via a light amount adjusting element 19.
- a beam splitter 21 is provided on the optical path of the traveling laser beam.
- the beam splitter 21 has a function of transmitting the laser beam traveling through the light amount adjusting element 19 and reflecting the light transmitted through a rising mirror described later.
- the optical pickup unit 5 includes a rising mirror 23 disposed on the optical path of the laser light that has passed through the beam splitter 21.
- the rising mirror 23 is configured to reflect the laser light transmitted through the beam splitter 21 in a direction orthogonal to the optical axis and directed to the recording medium 3.
- the optical pickup unit 5 supports the recording medium 3 so as to face the rising mirror 23 and so that the optical axis of the laser beam reflected by the rising mirror 23 is orthogonal to the surface of the protective layer. At the same time, a spindle motor 25 for rotating the recording medium 3 is provided.
- the optical pickup unit 5 includes an objective lens 27 interposed between the rising mirror 23 and the protective layer surface of the recording medium 3.
- This objective lens 27 has a function of focusing the laser beam reflected by the rising mirror 23 onto the recording track of the recording medium 3 and irradiating it as spot light.
- the optical pickup unit 5 is configured to be able to move the objective lens 27 along at least the radial direction of the recording medium 3 and the direction away from the recording medium 3, and is electrically connected to the servo driver 9. And an actuator 29 connected to the.
- the actuator 29 is configured to adjust the focus position and tracking position of the optical spot by moving the objective lens 27 based on control from the servo driver 9.
- the objective lens 27 has a function of receiving light (reflected light) reflected from the recording track of the recording medium 3 and outputting it as parallel light having a predetermined beam diameter during reproduction.
- the rising mirror 23 has a function of reflecting the reflected light sent through the objective lens 27 and sending it to the beam splitter 21.
- the beam splitter 21 has a function of reflecting the reflected light transmitted through the raising mirror 23.
- the optical pickup unit 5 is disposed on the optical path of the reflected light reflected by the beam splitter 21, and receives the reflected light and converts it into an electrical signal (hereinafter referred to as an RF signal). It has a light receiving unit 30.
- the power adjusting unit 7 is a laser beam emitted from a surface opposite to the LD unit output end in the package of the LD unit 15 (back-side laser beam: laser beam and power emitted from a normal output end) Are placed on the optical path of the same laser beam), the power (intensity) of the back side laser beam is constantly monitored, and the monitoring result is output as a monitor signal (electrical signal for monitoring, for example, monitor current)
- a photodiode (hereinafter simply referred to as a monitor diode) 31 and an amplifier 33 which is electrically connected to the monitor diode 31 and amplifies the monitor signal output from the monitor diode 31 are provided.
- the amplifier 33 is electrically connected to the computer 13, and the computer 13 records the recording medium based on the monitor signal amplified by the amplifier 33 and the currently set light transmittance of the light amount adjusting element 19. It is possible to monitor the power of irradiation laser light on 3.
- the power adjustment unit 7 includes a sample hold circuit (SZH) 35 that is electrically connected to the amplifier 33 and the computer 13.
- the sample hold circuit 35 has a function of sampling and holding the value of the monitor signal output from the amplifier 33 when APC (Automatic Power Control) of the computer 13 is executed (when on).
- the power adjustment unit 7 has an APC circuit 37 that is electrically connected to the sample hold circuit 35 and the LD driver 17.
- the APC circuit 37 uses the monitor signal value sampled and held by the sample and hold circuit 35 during APC execution, so that the monitor signal value is a predetermined power value of the irradiation laser beam on the recording medium 3 (
- the output waveform of the laser beam (output power level) output from the LD unit 15 is controlled (feedback control).
- the power adjustment unit 7 includes a light amount adjustment element driver (LC driver) 38.
- the LC driver 38 has a function of controlling the transmittance of the light amount adjusting element 19 by controlling the voltage applied to the light amount adjusting element 13 under the control of the computer 13.
- the recording / reproduction data processing unit 11 is connected to the interface 41 for receiving recording data (bit string data) input from the connected device and electrically connected to the interface 41 during recording.
- a buffer 43 that holds the recorded data, and a modem 45 that is electrically connected to the buffer 43.
- the interface 41, the noffer 43, and the modem unit 45 are electrically connected to the computer 13, and each operation is configured to be controlled by the computer 13, for example.
- the modulation / demodulation unit 45 performs recording on the recording data held in the buffer 43 for each predetermined unit based on the control of the computer 13 (in this embodiment, an ECC (Error Correlation Code) block) It has a function of adding an error correction code ⁇ for example, a PI (Parity Inner) correction code and a Z or PO (Parity Outer) correction code ⁇ to each unit ⁇ .
- ECC Error Correlation Code
- ECC block represents a unit of data recorded on the recording medium 3.
- the ECC block has 182 bytes (172 2-byte data + 10-byte PI correction code) X 208 rows (192 rows + 16 rows PO correction code) ).
- 172 bytes x 12 rows form one data frame
- 16 ECCs are collected to form one ECC block.
- the recording data of each frame of each ECC block after the error correction code is added is extracted from the wobble signal power obtained by the meandering recording track scan by the computer 13.
- the signal level is converted from a noise level to a low level or a signal that changes from a low level to a high level in the case of the value of the bit.
- the converted data ⁇ NRZI (Non Return to Zero Inverted) data ⁇ is data corresponding to the recording signal (record mark, pit) written to the recording track of the recording medium 3.
- bit length (run length; recording signal length) until the edge of the NRZI data changes varies depending on the modulation method or the like.
- NT ⁇ N is the type of recording medium 3
- recording medium 3 is a DVD, an integer greater than or equal to 3
- the power level on the recording medium 3 is automatically feedback-controlled to the recording power level, and the output waveform is deformed (for example, multi-track). Pulsed laser light is irradiated, and a recording signal corresponding to the run length of each NRZI data is written on the recording track of the recording medium 3.
- This laser beam output waveform control (multi-pulse control) is called a write strategy, and the width of the multi-pulse is set appropriately according to the power level of the laser beam on the recording medium 3. Further, it is possible to prevent the deterioration of the recording signal due to the continuous irradiation of the laser beam having a constant power level.
- the LD driver 17 controls the drive current (DC) based on the power control command sent from the APC circuit 37, and based on the superposition amount control command sent from the computer 13. For example, set the amplitude corresponding to the superposition amount control command with a high frequency of about several hundred MHz, and the current with the set amplitude (high frequency current) is, for example, the positive duty (on duty) in the sine wave
- It has a function F1 that drives the LD unit 15 by superimposing an intermittent high-frequency current with less than 50% on the drive current and applying it to the LD unit 15. This function F1 causes the LD unit 15 to output laser light modulated by high-frequency superposition with an on-duty of less than 50%.
- the LD driver 17 gives the controlled drive current to the LD unit 15 to drive the LD unit 15.
- the laser light whose output power level is controlled is output from the LD unit 15.
- the reflected light reflected from the corresponding recording signal is detected as an RF signal through the light receiving unit 30 by the operation of the optical pickup unit 5.
- the modulation / demodulation unit 45 amplifies the RF signal obtained by the light receiving unit 30, and from the amplified RF signal, a wobble modulation signal, a tracking error signal indicating an error (error) of tracking control, And focus error signal indicating focus control error.
- Each of these functions has a function of generating and a function of demodulating (decoding) the reproduction data (bit string data).
- the demodulated playback data is sent to the computer 13, and this computer 13 performs error detection processing, judgment processing for determining whether or not the detected error is correctable, and correction for performing error correction when correction is possible. Processing is performed.
- the reproduction data after the correction processing is held in the buffer 43 by the processing of the computer 13.
- the interface 41 has a function of outputting reproduction data held in the buffer 43 to the information output device according to the control of the information output device connected to the interface 41! / RU
- the computer 13 has setting information on the linear velocity of the recording medium 3 (speed of laser light traveling on the medium 3 during recording and Z or reproduction; for example, 1 ⁇ speed, 2 ⁇ speed,..., 32 ⁇ speed, etc.)
- An input unit 47 for inputting various information and instructions such as an ECC block defect judgment registration processing execution instruction and a trial writing execution instruction to the computer 13 by a user operation is connected. Also, based on the linear velocity setting information set by the input unit 47 and passed through the computer 13, the computer 13 and the servo driver 9 are given a linear velocity command corresponding to the linear velocity setting information.
- a digital signal processor (DSP) for sending to 9 is connected.
- DSP digital signal processor
- the servo driver 9 drives and controls the spindle motor 25 according to the linear velocity command from the DSP 49, and rotates the recording medium 3 while keeping the linear velocity set and input by the input unit 47 constant. It has a function (CLV: Constant Linear Velocity) or a function to rotate while keeping the angular velocity constant (CAV: Constant Angular Velocity) based on the set linear velocity.
- CLV Constant Linear Velocity
- CAV Constant Angular Velocity
- the servo driver 9 controls the actuator 29 based on the tracking error signal and the focus error signal obtained by the modem unit 45, thereby focusing the spot light irradiated on the recording track of the recording medium 3. It has a function to perform position control and tracking control respectively!
- a liquid crystal element whose light transmittance is changed by control information applied from the computer 13 via the LC driver 38 is used as the light amount adjusting element 19.
- the invention is not limited to this configuration.
- variable optical attenuator ⁇ variable ND (Neutral Density) in which the amount of light attenuation (in other words, the amount of transmitted light) changes due to a change in voltage applied from the computer 13 via a driver.
- Filters, etc. ⁇ , polarizing elements (wavelength plates, liquid crystal elements, etc.) and beamsplitters It is also possible to use elements.
- a light quantity adjusting unit according to the present invention by arranging a polarizing element instead of the light quantity adjusting element 19 in Fig. 2 and combining the beam splitter 21.
- the optical axis direction (polarization direction) of the polarization element is changed by a predetermined angle from the polarization direction of the incident laser light by the control information applied from the computer 13 via the driver, and passes through the polarization element.
- the light transmittance of the incident laser light after passing through the polarizing element and the beam splitter 21 is changed by separating the predetermined amount of light in the subsequent laser light and the remaining amount of light by the beam splitter 21. Can do.
- the computer 13 performs the control process of the LD driver 17 and the light amount adjustment element 19 in the optical pickup unit 5, the control process of the power adjustment unit 7, and the control process of the servo driver 9. And the process relating to error detection and / or correction in the recording / reproduction data processing unit 11 is executed according to the corresponding program P loaded in the second memory 13b.
- the power adjusting unit 7 of the computer 13 in the case of reproducing the recording data recorded on the recording track of the recording medium 3,
- the control process for the LD driver 17 and the light amount adjusting element 19 will be mainly described.
- the computer 13 when reproducing the recording data recorded on the recording track of the recording medium 3, stores data in the second memory 13b.
- the processing shown in Fig. 3 is executed according to at least one program P that is loaded.
- step S1 the computer 13 executes a recording medium playback (PLAY) process in a state where the light transmittance of the light amount adjusting element 19 is set to 100% which is an initial ratio.
- PLAY recording medium playback
- the light transmittance of the light amount adjusting element 19 is 100% when the light amount is not applied. This means the light transmittance of the adjusting element 19.
- the computer 13 controls the spindle motor 25 via the DSP 49 and the servo driver 9 and moves the recording medium 3 to, for example, CLV at the linear velocity set and input by the input unit 47.
- the power level of the irradiation laser beam on the recording medium 3 is set to a predetermined level for reproduction (hereinafter referred to as a reproduction power level), and the sample hold circuit 35 is set based on the set reproduction power level.
- APC ON control is performed, and a superimposition amount control command is sent to the LD driver 17 with a predetermined current level as superimposition amount (assuming superimposition amplitude A1).
- the sample hold circuit 35 samples and outputs the value of the monitor signal detected by the monitor diode 31 and output from the amplifier 33 to the APC circuit 37.
- the APC circuit 37 sends a power control command (monitor power level) corresponding to the sampled and held monitor signal value to the LD driver 17 so as to substantially match the reproduction power level. .
- the LD driver 17 drives the drive current based on the power control command sent from the APC circuit 37.
- DC is controlled, and based on the superposition amount control command sent from the computer 13, for example, a current (high frequency) having a high frequency of about several hundred MHz and a superposition amplitude A1 corresponding to the superposition amount control command.
- a current high frequency
- the intermittent high frequency current Ioutl in which the positive duty (on duty) in the sine wave is less than 50% is superimposed on the drive current and applied to the LD unit 15 to drive the LD unit 15.
- the laser power of high frequency superposition with less than 50% on-duty is output with 15 units of LD unit.
- the operation of the optical pickup unit 5 irradiates the recording signal written on the recording track of the recording medium 3 with the laser beam superimposed at a high frequency.
- the power of the irradiation laser beam on the recording medium 3 is maintained substantially constant at the reproduction power level by the APC control described above.
- the reflected light reflected from the corresponding recording signal is detected as an RF signal through the light receiving unit 30 by the operation of the optical pickup unit 5.
- the detected RF signal passes through the modulation / demodulation unit 45 and the reproduction data (bit string data) of the ECC block. After being decoded, it is transmitted to the computer 13, and after error correction processing, it is output to an information output device or the like via the notch 43 and the interface 41.
- step S1 the computer 13 monitors the linear velocity of the recording medium 3 via the servo driver 9, and determines whether the linear velocity is equal to or higher than a predetermined velocity (step S1). S 2).
- This predetermined speed is the speed at which the time required to pass the shortest run length (3T for DVD, 2T for Blu-ray D ISC) at the predetermined speed is close to the period of the intermittent high-frequency current loutl. Is set as Hereinafter, this predetermined speed is referred to as a threshold speed.
- step S2 determines whether the result of determination in step S2 is NO (N), that is, if the monitor linear velocity is less than the threshold velocity corresponding to the shortest run length, the computer 13 at the current reproduction linear velocity, It is determined that the recording signal does not pass the laser beam scanning position during the laser beam OFF period, in other words, the recording signal can be read by the laser beam, and the process is terminated.
- step S2 determines whether the result of determination in step S2 is YES (Y) or higher than the threshold velocity. If the result of determination in step S2 is YES (Y), that is, if the monitor linear velocity is equal to or higher than the threshold velocity, the computer 13 indicates that the recording signal is at the laser beam off period at the current reproduction linear velocity. In other words, it is determined that there is a possibility that the recording signal may not be read by the laser beam, and the process proceeds to step S3.
- step S3 the computer 13 performs the APC control (sampling on control), that is, maintains the power of the irradiation laser light on the recording medium 3 through the LC driver 38 while maintaining the power of the irradiation laser light substantially constant.
- the voltage applied to the light amount adjusting element 19 is controlled to reduce the light transmittance of the light amount adjusting element 19 to a predetermined value (for example, 50%).
- the light transmittance of the light amount adjusting element 19 is 50%.
- the ratio between the monitor power level when no voltage is applied to the light amount adjusting element 19 (transmittance 100%) and the monitor power level when controlling the applied voltage. Means approximately 50%.
- the emission power of the laser light output from the LD unit 15 is increased by reducing the light transmittance of the light amount adjusting element 19 and by APC control (constant control of the irradiation laser light power).
- step S4 In parallel with step S3 or before and after the processing, the computer 13 As a control command, a superimposition amount reduction command with a superposition amplitude A2 that is lower than the superposition amplitude A1 is transmitted to the LD driver 17 (step S4).
- the LD driver 17 controls the drive current based on the power control command sent from the APC circuit 37, and superimposes it on the drive current based on the superimposed amount reduction command sent from the computer 13.
- the amplitude A1 of the intermittent high-frequency current lout 1 is reduced to the amplitude A2 corresponding to the superposition amount reduction command.
- the level of the high-frequency superimposed laser beam output from the LD unit 15 can be set to always on (beyond the off level) (see Fig. 1; superimposed amount setting function F1).
- FIG. 4 shows the intermittent high-frequency currents Ioutl and Iout2 that are superimposed on the drive current Id from the APC circuit 37 and the respective intermittent high-frequency currents Ioutl by the processes in steps S1 to S4.
- FIG. 5 is a diagram showing a relationship between laser light outputs Pol and Po2 output from the LD unit 15 corresponding to Iout2.
- Ith in FIG. 4 is a threshold level that defines the laser light output (oscillation) in the LD unit 15.
- the LD unit 15 Configured to start output.
- step S2 if the monitor linear velocity is less than the threshold velocity corresponding to the shortest run length (step S2 ⁇ NO), the high-frequency current Io utl having the amplitude A1 continues to be APC. Since it is superimposed on the drive current from the circuit 37, the output waveform of the laser beam Po output from the LD unit 15 is turned on intermittently with reference to the laser beam off level as shown in FIG.
- the output waveform Pol, ie, multimode can be set. As a result, it is possible to reduce return light noise during reproduction.
- step S2 determines whether the monitor linear velocity is equal to or higher than the threshold velocity corresponding to the shortest run length. If the result of determination in step S2 is that the monitor linear velocity is equal to or higher than the threshold velocity corresponding to the shortest run length (step S2 ⁇ YES), the comparison between the laser light output waveform Pol and the recording signal is performed. As a result, the recording signal may pass during the laser beam off period.
- the amplitude A1 of the high-frequency current Ioutl is reduced to the amplitude A2 in a state where the power of the irradiation laser light on the recording medium 3 is maintained substantially constant at the reproduction power level by the APC control. Is superimposed on the drive current as a high-frequency current Iout2.
- the output waveform of the laser beam Po output from the LD unit 15 has a constant level higher than the laser beam off level, and its average value (average level: (Corresponding to the drive current value from the APC circuit 37) can be set to the output waveform Po2 that is the same as the laser light output waveform Pol.
- the recording signal always passes the laser beam scanning position in the laser light output ON state, and the recording signal, that is, the edge of each recording mark can be reliably read. Can do.
- the reproduction linear velocity of the recording medium 3 is set to a velocity at which the recording signal may pass through the laser beam scanning position during the laser beam off period.
- the recording signal can be reliably read by reducing the amount of superposition of the intermittent high-frequency current to the drive current of the LD unit 15 according to the speed change.
- the laser beam can be intermittently turned on and off via the LD unit 15 while maintaining the power of the irradiation laser beam on the recording medium 3 substantially constant. Deterioration of the recording layer of the recording medium 3 can be prevented.
- the amount of superposition of the intermittent high-frequency current with respect to the drive current of the LD unit 15 is reduced according to the change in the reproduction linear velocity of the recording medium 3, so that the high-frequency current is reduced. Unwanted radiation caused can also be suppressed.
- step S4 of FIG. 3 in the present embodiment the computer 13 instructs the LD driver 17 as a superposition amount control command so that the superposition amplitude A2 is an amplitude lower than the superposition amplitude A1.
- the LD driver 17 sets the amplitude A1 of the intermittent high-frequency current Ioutl superimposed on the drive current to the amplitude corresponding to the superposition amount reduction command.
- the present invention is not limited to this configuration.
- step S4 in FIG. 3 the computer 13 sends a superimposition amplitude (superimposition amount) zero, that is, an intermittent high-frequency current to the LD driver 17 as a superposition amount control command.
- the superimposition amount reduction command for superimposing (superimposition off) is transmitted, and the LD driver 17 is based on the power control command sent from the APC circuit 37 based on the superposition amount reduction command sent from the converter 13. It is also possible to drive the LD unit 15 by applying the controlled drive current to the LD unit 15 as it is (without superimposing the intermittent high-frequency current).
- the reproduction linear velocity of the recording medium 3 is set to a velocity at which the recording signal may pass through the laser beam scanning position during the laser beam off period.
- the recording signal can be read reliably by setting the superposition amount of the intermittent high-frequency current to the drive current of the LD unit 15 to zero (that is, superposition off) according to the speed change.
- a data recording / reproducing system 1 that is resistant to return light noise and does not skip recorded signals while maintaining the effect of improving the reproduction efficiency due to an increase in the reproduction linear velocity. be able to.
- a data recording / reproducing system according to a second embodiment of the present invention will be described with reference to the drawings.
- the hardware components of the data recording / reproducing system according to the second embodiment are substantially the same as the hardware configuration of the data recording / reproducing system 1 according to the first embodiment. A description thereof will be omitted or simplified.
- the computer 13 when reproducing the recorded data recorded on the recording track of the recording medium 3, the computer 13 is at least loaded to the second memory 13b. According to one program P, the process shown in FIG. 5 is executed instead of the process shown in FIG.
- the computer 13 executes the light transmittance initial ratio setting process, the recording medium reproduction process, and the linear velocity determination process of the light amount adjusting element 19 (Fig. 3). 5; see steps S 10 and 11).
- the LD driver 17 controls the drive current based on the power control command sent from the APC circuit 37, and based on the superposition amount control command sent from the computer 13. , Intermittent high frequency current I with superposition amplitude A1 corresponding to superposition amount control command I The outl is superimposed on the drive current and applied to the LD unit 15 to drive the LD unit 15.
- laser light that is multi-mode modulated with an on-duty of less than 50% is output from the LD unit 15 force.
- the operation of the optical pickup unit 5 irradiates the recording signal written on the recording track of the recording medium 3 and corresponding to the ECC block to be reproduced with high-frequency superimposed laser light.
- the power of the irradiation laser beam on the recording medium 3 is maintained substantially constant at the reproduction power level by the APC on control described above.
- the reflected light reflected from the corresponding recording signal based on the irradiated laser light is detected as an RF signal via the light receiving unit 30 by the operation of the optical pickup unit 5.
- the detected RF signal is decoded as reproduction data (bit string data) of the ECC block via the modem unit 45 and then transmitted to the computer 13.
- step S11 determines whether the result of determination in step S11 is YES, that is, if the monitor linear velocity is equal to or higher than the threshold velocity. It is determined that there is a possibility of passing through the optical scanning position, in other words, there is a possibility that the recording signal may become unreadable by the laser beam, and the process proceeds to step S12.
- step S12 the computer 13 obtains an error rate as a reproduction characteristic based on the transmitted reproduction data of the ECC block, and the obtained error rate is difficult to reproduce the corresponding ECC block. It is determined whether or not the threshold is equal to or higher than a predetermined threshold value that is a criterion for determining whether or not the force is acceptable.
- the reproduction characteristics in the present embodiment serve as an index for evaluating reproduction data obtained by the recording / reproduction data processing unit 11 and the computer 13.
- an error rate indicating the ratio of the PI error (number of error bytes in each ECC block Z number of normal bytes) indicating the number of error noises for all rows in each ECC block is used as a reproduction characteristic.
- step S12 If the result of determination in step S12 is NO, that is, if the error rate is less than the predetermined threshold, the computer 13 determines that the corresponding ECC block is in a reproducible state, and step S12 Move to 15 processing. As a result, the playback data of the corresponding ECC block Is output to an information output device or the like via the buffer 43 and the interface 41.
- step S12 determines whether the result of determination in step S12 is YES, that is, if the error rate is equal to or higher than a predetermined threshold.
- the computer 13 outputs a recording signal due to the monitor linear velocity being equal to or higher than the threshold velocity.
- the error rate exceeds a predetermined threshold value, and it is determined that the corresponding ECC block has become difficult to reproduce, and the process proceeds to step S13.
- step S13 as in step S3 shown in FIG. 3, the computer 13 performs the above APC on control, that is, maintains the uniformity of the irradiation laser light on the recording medium 3 substantially constant.
- the voltage applied to the light amount adjusting element 19 is controlled via the LC driver 38 to reduce the light transmittance of the light amount adjusting element 19 to a predetermined value (for example, 50%).
- a predetermined value for example, 50%.
- step S14 the computer 13 transmits, to the LD driver 17, a superposition amount reduction command that sets a superposition amplitude A2 that is lower than the superposition amplitude A1 as a superposition amount control command.
- the LD driver 17 controls the drive current based on the power control command sent from the APC circuit 37, and superimposes it on the drive current based on the superposition amount reduction command sent from the computer 13.
- the amplitude A1 of the intermittent high-frequency current lout 1 is reduced to the amplitude A2 corresponding to the superposition amount reduction command.
- the level of the high-frequency superimposed laser beam output from the LD unit 15 can always be set to on (see FIG. 4).
- step S14 After the process of step S14 is completed or if the result of determination in step S12 is NO (when the ECC block can be reproduced), the computer 13 proceeds to step S15.
- step S15 the computer 13 superimposes the monitor signal value sent from the monitor diode 31 via the amplifier 33 and / or the intermittent harmonic current lout 1 given from the LD driver 17 to the LD unit 15. Based on the drive current value, the output power of the laser beam output from the LD unit 15 is obtained, and a margin of a predetermined percentage (for example, 10%) is obtained from the calculated rated power of the LD power unit 15. Whether threshold power has been reached Judge whether or not.
- a margin of a predetermined percentage for example, 10%
- step SI5 determines whether the output power of the laser beam output from the LD unit 15 is less than the threshold power of the LD unit 15. If the determination result of step SI5 is NO, that is, if the output power of the laser beam output from the LD unit 15 is less than the threshold power of the LD unit 15, the computer 13 proceeds to step S12. Return.
- the reflected light reflected from the corresponding recording signal is detected again as an RF signal via the light receiving unit 30 by the operation of the optical pickup unit 5, and the detected RF signal is detected. Is decoded as reproduction data (bit string data) of the ECC block via the modulation / demodulation unit 45 and then transmitted to the computer 13.
- the computer 13 obtains an error rate as a reproduction characteristic based on the ECC block reproduction data transmitted again, and determines whether or not the obtained error rate is equal to or greater than a predetermined threshold (step S 12 reference).
- the computer 13 performs the processing of steps S12 to S15 (comparison determination processing for the error rate threshold, light transmittance reduction processing of the light amount adjustment element 19, superimposition amount reduction processing via the LD driver 17, laser (Comparison and judgment processing for threshold power of light output power), the power at which determination of step S12 is NO (error rate is less than the predetermined threshold) or YES at step S15 (laser light output power reaches threshold power) Repeat until it becomes.
- step S12 If the determination in step S12 is NO (the error rate is less than the predetermined threshold), the level of the multimode-modulated laser beam output from the LD unit 15 is always set to ON, and It is determined that the error rate of the corresponding ECC block has been improved to a reproducible state by increasing the laser beam emission power while the laser beam irradiation power on the recording medium 3 is maintained substantially constant. As a result, the reproduction data of the corresponding ECC block is output to the information output device or the like via the buffer 43, the interface 41, and the like.
- step S12 determines whether the C block is a block is a block. If the determination in step S15 is NO, the computer 13 returns to step S12 and returns to the next playback target EC. The above-described processing of step S12 to step S15 is repeatedly executed for the C block.
- step S 14 the process proceeds to the process of step S 15.
- YES that is, the emission power of the laser beam output from the LD unit 15 is
- the computer 13 the processing of Steps S12 to S15 (ECC block regeneration processing) is repeatedly executed (Step S16).
- the reproduction linear velocity of the recording medium 3 is set to a velocity at which the recording signal may pass the laser beam scanning position during the laser beam off period. Even when the error rate exceeds a predetermined threshold value indicating that reproduction is difficult, the laser beam is reduced by reducing the light transmittance of the light quantity adjusting element 19 while maintaining the laser beam irradiation power on the recording medium 3 substantially constant. While increasing the output power, the amount of superposition of the intermittent high-frequency current to the drive current of the LD unit 15 can be reduced according to the speed change.
- the recorded signal can be read reliably.
- the reproduction linear velocity it is possible to provide a data recording / reproducing system that is resistant to return light noise and has no skipping of the recording signal while improving the reproduction efficiency due to the increase in the recording rate.
- the amount of superposition of the intermittent high-frequency current with respect to the drive current of the LD unit 15 is reduced according to the change in the reproduction linear velocity of the recording medium 3, so that the high-frequency current is reduced. Unwanted radiation caused can also be suppressed.
- FIG. 6 uses a Blu-ray Disc as the recording medium 3 and reproduces data recorded on the Blu-ray Disc using the processing of steps S10 to S16 shown in FIG. 6 is a graph (symbol G1) showing an example of a relationship between a change in reproduction speed and a change in error rate when reproduction is performed while changing the linear velocity.
- the horizontal axis represents a change in multiple of the reproduction linear velocity (1 is 1 ⁇ , 2 is 2 ⁇ ), and the vertical axis represents the error rate change.
- reference numeral G2 represents a case where data recorded on a B1 u-ray Disc is reproduced while changing the reproduction linear velocity using the simple high-frequency superposition described in the background art. It is a graph showing an example of the relationship between a reproduction speed change and an error rate change. Furthermore, in FIG. 6, reference numeral G3 represents the relationship between the change in playback speed and the change in error rate when data recorded on a Blu-ray Disc without high-frequency superposition is played while changing the playback linear speed. It is a graph showing an example.
- step S 14 in FIG. 5 the computer 13 performs superimposition as a superposition amount control command to the LD driver 17. It is also possible to transmit a superposition amount reduction command for setting the amplitude to zero (intermittent high-frequency current superposition off), and the same effect as that of the modification of the first embodiment can be obtained.
- a data recording / reproducing system according to a third embodiment of the present invention will be described with reference to the drawings.
- the hardware components of the data recording / reproducing system according to the third embodiment are substantially the same as the hardware configuration of the data recording / reproducing system 1 according to the first embodiment. A description thereof will be omitted or simplified.
- the computer 13 when reproducing the recording data recorded on the recording track of the recording medium 3, the computer 13 is at least imported to the second memory 13b. According to one program P, the process shown in FIG. 7 is executed instead of the process shown in FIG.
- the computer 13 sets the light transmittance of the light amount adjusting element 19 to an arbitrary ratio (for example, With the initial ratio set to 100%, the recording medium playback process shown in step S1 of FIG. 3 is executed (step S20), and then the linear velocity determination process shown in step S2 of FIG. 3 is executed. (Step S21).
- step S21 If the result of determination in step S21 is YES, that is, if the monitor linear velocity is equal to or higher than the threshold velocity, the computer 13 scans the laser beam during the laser beam OFF period at the current reproduction linear velocity. It is determined that there is a possibility of passing through the position, in other words, there is a possibility that the edge portion of the recording signal may become unreadable by the laser beam, and the process proceeds to step S 22.
- step S22 the computer 13 transmits to the LD driver 17 a superimposition amount reduction command that sets the amplitude lower than the superposition amplitude A1 as the superposition amplitude A2 as the superposition amount control command.
- the LD driver 17 controls the drive current based on the power control command sent from the APC circuit 37, and superimposes it on the drive current based on the superimposed amount reduction command sent from the computer 13.
- the amplitude A1 of the intermittent high-frequency current lout 1 is reduced to the amplitude A2 corresponding to the superposition amount reduction command.
- the level of the high-frequency superimposed laser beam output from the LD unit 15 can be always set to on (beyond the off level) (see FIG. 4).
- the reproduction linear velocity of the recording medium 3 is determined so that the recording signal passes through the laser beam scanning position during the laser beam off period. Even when the speed is set to a fear, the recording signal can be reliably read by reducing the amount of intermittent high-frequency current superimposed on the drive current of the LD unit 15 according to the speed change.
- step S23 in Fig. 7 the computer 13 performs superimposition as a superposition amount control command to the LD driver 17. It is also possible to transmit a superposition amount reduction command for setting the amplitude to zero (intermittent high-frequency current superposition off), and the same effect as that of the modification of the first embodiment can be obtained.
- the computer 13 when reproducing the recording data recorded on the recording track of the recording medium 3, the computer 13 is at least imported to the second memory 13b.
- the process shown in FIG. 8 is executed instead of the process shown in FIG.
- the process shown in FIG. 8 is executed for each ECC block of recording data to be reproduced.
- step S30 the computer 13 is equivalent to step S10 shown in FIG. 5 with the light transmittance of the light amount adjusting element 19 set to an arbitrary ratio (for example, an initial ratio of 100%).
- a recording medium reproduction process is executed.
- step S31 the computer 13 executes a linear velocity determination process equivalent to step S11 shown in FIG.
- step S31 If the result of determination in step S31 is YES, that is, if the monitor linear velocity is greater than or equal to the threshold velocity, the computer 13 proceeds to processing in step S32, and in step S32, the same as step S12 is performed. Judgment processing for a predetermined threshold of error rate is executed.
- step S32 determines that the corresponding ECC block has become difficult to reproduce and proceeds to step S33. .
- step S33 the computer 13 executes a superimposition amount reduction command transmission process equivalent to that in step S14.
- the reproduction linear velocity of the recording medium 3 is set to a velocity at which the recording signal may pass through the laser beam scanning position during the laser beam off period. Even when the error rate is equal to or higher than a predetermined threshold value indicating difficulty in reproduction, the amount of intermittent high-frequency current superimposed on the drive current of the LD unit 15 can be reduced according to the speed change. [0150] By reducing the amount of intermittent high-frequency current superimposed on the drive current of the LD unit 15, the recorded signal can be read reliably. As a result, as in the first embodiment, the reproduction linear velocity Thus, it is possible to provide a data recording / reproducing system without skipping reading of the recorded signal, while improving the reproduction efficiency by increasing the number of recordings.
- step S34 in Fig. 8 the computer 13 performs superimposition as a superposition amount control command to the LD driver 17. It is also possible to transmit a superposition amount reduction command for setting the amplitude to zero (intermittent high-frequency current superposition off), and the same effect as that of the modification of the first embodiment can be obtained.
- FIG. 9 is a block diagram showing a schematic configuration of a data recording / reproducing system 1A according to the fifth embodiment of the present invention.
- the LD driver 17A of the data recording / reproducing system 1A uses the superposition frequency sent from the computer 13 instead of the superposition amount setting function F1 described in the first to fourth embodiments. Based on the control command, for example, a superposition frequency of the order of several hundred MHz is set. The function F2 is superimposed on
- the hardware components other than the LD driver 17A are substantially the same as the hardware configuration of the data recording / reproducing system 1 according to the first embodiment. Omit or simplify.
- the computer 13 when reproducing the recording data recorded on the recording track of the recording medium 3, the computer 13 is at least imported to the second memory 13b. According to one program P, the process shown in FIG. 10 is executed instead of the process shown in FIG.
- step S40 the computer 13 reproduces the recording medium with the light transmittance of the light amount adjusting element 19 set to the initial ratio of 100% (a state in which no voltage is applied). Execute the process.
- the computer 13 controls the spindle motor 25 via the DSP 49 and the servo driver 9 and moves the recording medium 3 to, for example, CLV at the linear velocity set and input by the input unit 47. Rotate and set the power level of the irradiation laser light on the recording medium 3 to the playback power level. Based on this playback power level, the sample hold circuit 35 is APC-on controlled, and a predetermined frequency is superimposed. A superposition frequency control command with a frequency (for example, superposition frequency fl on the order of several hundred MHz) is sent to the LD driver 17A.
- a frequency for example, superposition frequency fl on the order of several hundred MHz
- the sample hold circuit 35 samples the value of the monitor signal detected by the monitor diode 31 and output from the amplifier 33, and outputs it to the APC circuit 37.
- the APC circuit 37 issues a power control command for causing the monitor power level corresponding to the value of the sampled and held monitor signal to substantially match the reproduction power level.
- the LD driver 17A controls the drive current based on the power control command sent from the APC circuit 37, and on the basis of the superimposed frequency control command sent from the computer 13, the LD driver 17A has a predetermined frequency having the superimposed frequency fl.
- an amplitude high-frequency current for example, an intermittent high-frequency current IoutlO in which the on-duty in a sine wave is less than 50% is superimposed on the drive current and applied to the LD unit 15 to drive the LD unit 15.
- IoutlO an intermittent high-frequency current IoutlO in which the on-duty in a sine wave is less than 50%
- the operation of the optical pickup unit 5 irradiates the recording data recorded on the recording track of the recording medium 3 with the laser beam superimposed at a high frequency.
- the power of the irradiation laser beam on the recording medium 3 is maintained substantially constant at the reproduction power level by the APC control described above.
- the reflected light reflected from the corresponding recording signal is detected as an RF signal through the light receiving unit 30 by the operation of the optical pickup unit 5.
- the detected RF signal is decoded as reproduction data (bit string data) of the ECC block via the modulation / demodulation unit 45, and then transmitted to the computer 13. After error correction processing, And output to an information output device via the interface 41.
- the computer 13 monitors the linear velocity of the recording medium 3 via the servo driver 9, and determines whether the linear velocity is equal to or greater than the threshold velocity (Ste S41).
- step S41 If the result of determination in step S41 is NO, that is, if the monitor linear velocity is less than the threshold velocity, the computer 13 performs laser recording during the laser light off period at the current reproduction linear velocity. It is determined that the optical signal does not pass through the optical scanning position, in other words, the recording signal can be read out by the laser beam, and the process is terminated.
- step S41 determines whether the result of determination in step S41 is YES, that is, if the monitor linear velocity is equal to or higher than the threshold velocity. It is determined that there is a possibility of passing the position, in other words, there is a possibility that the recording signal may become unreadable by the laser beam, and the process proceeds to step S42.
- step S42 the computer 13 transmits to the LD driver 17A, as a superposition frequency control command, a superposition frequency increase command having a superposition frequency of the frequency f2 higher than the superposition frequency fl.
- the LD driver 17A superimposes on the drive current based on the superimposed frequency increase command sent from the computer 13 while controlling the drive current based on the power control command sent from the APC circuit 37.
- the frequency fl of the intermittent high-frequency current IoutlO is increased to the frequency f2 corresponding to the superposition frequency increase command.
- the level of the high-frequency superimposed laser beam output from the LD unit 15 can be set to always on (beyond the off level) (see FIG. 9; superimposed frequency setting function F2).
- FIG. 11 shows the intermittent high-frequency currents Ioutl0 and Ioutll superimposed on the drive current Id from the APC circuit 37 by the processing of step S40 to step S42, and the missing high-frequency currents Ioutl0, It is a figure which shows the relationship with laser beam output Pol0 and Poll output from LD unit 15 corresponding to Ioutll.
- step S41 if the monitor linear velocity is less than the threshold velocity corresponding to the shortest run length of the recording signal (step S41 ⁇ NO), the superposition frequency fl is set. Since the high-frequency current IoutlO is continuously superimposed on the drive current from the APC circuit 37, the output waveform of the laser light Po output from the LD unit 15 is synchronized with the high-frequency current IoutlO as shown in FIG.
- the output waveform PolO can be multimode. As a result, it is possible to reduce return light noise during reproduction.
- step S42 determines whether the monitor linear velocity is equal to or higher than the threshold velocity. If the result of determination in step S42 is that the monitor linear velocity is equal to or higher than the threshold velocity (step S42 ⁇ YES), recording is performed so that the comparison force between the laser light output waveform PolO and the recording signal is also divided. There is a possibility that the signal passes during the laser beam off period.
- the superposed frequency fl of the high-frequency current IoutlO is superposed while the power of the irradiation laser light on the recording medium 3 is maintained substantially constant at the reproduction power level by the APC on control.
- the frequency rises to f2 and is superimposed on the drive current as the high-frequency current Ioutll.
- the superposition frequency f2 is set so that the period corresponding to the superposition frequency f2 is shorter than the time length corresponding to the shortest run length of the recording signal.
- the output waveform of the laser beam Po output from the LD unit 15 is longer than the time required for the period to pass the minimum signal length of the recording signal at the threshold speed. Shortened output waveform Po2 can be set.
- the recording signal always passes the laser beam scanning position in the laser beam output on state, and the recording signal can be read reliably.
- the reproduction linear velocity of the recording medium 3 is set to a velocity at which the recording signal may pass the laser beam scanning position during the laser beam off period.
- the recording signal can be read reliably by increasing the superposition frequency of the intermittent high-frequency current to the drive current of the LD unit 15 according to the speed change.
- a data recording / reproducing system will be described with reference to the drawings.
- the hardware of the data recording / reproducing system according to the sixth embodiment Since the components are substantially the same as the hardware configuration of the data recording / reproducing system 1A according to the fifth embodiment, the same reference numerals are given and the description thereof is omitted or simplified.
- the computer 13 when reproducing the recorded data recorded on the recording track of the recording medium 3, the computer 13 is loaded with at least one loaded into the second memory 13b.
- the process shown in FIG. 12 is executed instead of the process shown in FIG. In this embodiment, the process shown in FIG. 12 is executed for each ECC block of recording data to be reproduced.
- the computer 13 performs the light transmittance initial ratio setting process, the recording medium reproduction process, and the linear velocity determination process of the light quantity adjusting element 19 respectively. Run (see Figure 12; steps S50 and 51).
- the LD driver 17A controls the drive current based on the power control command sent from the APC circuit 37, and superimposes based on the superposition frequency control command sent from the computer 13.
- the intermittent high frequency current IoutlO having the superimposed frequency fl corresponding to the frequency control command is superimposed on the drive current and applied to the LD unit 15 to drive the LD unit 15.
- the laser light superposed at a high frequency with an on-duty of less than 50% is output from the LD unit 15 force.
- the operation of the optical pickup unit 5 irradiates a plurality of recording marks corresponding to the reproduction target ECC block written on the recording track of the recording medium 3 with high-frequency superimposed laser light. .
- the power of the irradiation laser light on the recording medium 3 is maintained substantially constant at the reproduction power level by the APC control described above.
- the reflected light reflected from the corresponding recording signal is detected as an RF signal through the light receiving unit 30 by the operation of the optical pickup unit 5.
- the detected RF signal is decoded as reproduction data of the ECC block via the modulation / demodulation unit 45 and then transmitted to the computer 13.
- step S51 determines whether the result of determination in step S51 is YES, that is, if the monitor linear velocity is greater than or equal to the threshold velocity.
- the computer 13 uses the current reproduction linear velocity to record the recording signal during the laser beam off period. It is determined that there is a possibility of passing the optical scanning position, in other words, there is a possibility that the edge portion of the recording signal may become unreadable by the laser beam, and the step The processing shifts to S52.
- step S52 the computer 13 obtains an error rate as reproduction characteristics based on the transmitted reproduction data of the ECC block, and determines whether or not the obtained error rate is equal to or greater than a predetermined threshold value.
- step S52 determines that the error rate is greater than or equal to a predetermined threshold
- the computer 13 determines that the corresponding ECC block has become difficult to reproduce and proceeds to step S53. move on.
- step S53 the computer 13 sends, as the superposition frequency control command, a superposition frequency increase command having the superposition frequency f2 higher than the superposition frequency fl as the LD driver 17.
- the LD driver 17A controls the drive current based on the power control command sent from the APC circuit 37, and superimposes it on the drive current based on the superimposed frequency increase command sent from the computer 13.
- the superposition frequency fl of the intermittent high-frequency current IoutlO is increased to the superposition frequency f2 corresponding to the superposition frequency increase command.
- the reproduction linear velocity of the recording medium 3 is set to a velocity at which the recording signal may pass through the laser beam scanning position during the laser beam off period. Even when the error rate is equal to or higher than a predetermined threshold value indicating that reproduction is difficult, the superimposed frequency of the intermittent high-frequency current with respect to the drive current of the LD unit 15 can be increased according to the speed change.
- FIG. 13 shows a case where a Blu-ray DISC is used as the recording medium 3 and the data recorded on the Blu-ray DISC using the processing of steps S50 to S53 shown in FIG. Changes in playback speed and error rate when playing at different speeds It is a graph (code
- the horizontal axis represents a change in multiple of the reproduction linear velocity (1 represents 1 ⁇ speed, 2 represents 2 ⁇ speed,..., And the vertical axis represents the error rate change.
- reference numeral G12 represents a change in reproduction speed when data recorded on a Blu-ray DISC is reproduced while changing the reproduction linear velocity using the simple high-frequency superposition described in the background art.
- 5 is a graph showing an example of the relationship between the error rate change and the error rate.
- a data recording / reproducing system according to a seventh embodiment of the present invention will be described with reference to the drawings.
- the hardware components of the data recording / reproducing system according to the seventh embodiment are substantially the same as the hardware configuration of the data recording / reproducing system 1A according to the fifth embodiment, and therefore the same reference numerals are used. Therefore, the explanation is omitted or simplified.
- the computer 13 when reproducing the recording data recorded on the recording track of the recording medium 3, the computer 13 is loaded with at least one loaded into the second memory 13b. Instead of the process shown in FIG. 10, the process shown in FIG.
- the computer 13 executes processing equivalent to steps S40 and S41 shown in FIG.
- the computer 13 executes the recording medium reproduction process with the light transmittance of the light amount adjusting element 19 set to the initial ratio of 100% (step S40), and then executes the linear velocity determination process. (Step S41).
- step S41 If the result of determination in step S41 is YES, that is, if the monitor linear velocity is equal to or higher than the threshold velocity, the computer 13 scans the laser beam during the laser beam OFF period at the current reproduction linear velocity. It is determined that there is a possibility that the recording signal may pass through the position. To do.
- step S60 the computer 13 performs the APC control as in step S3 shown in FIG. 3, that is, the LC driver while maintaining the power of the irradiation laser light on the recording medium 3 substantially constant.
- the voltage applied to the light amount adjusting element 19 is controlled via 38 to reduce the light transmittance of the light amount adjusting element 19 to a predetermined value (for example, 50%).
- the emission power of the laser light output from the LD unit 15 is increased by reducing the light transmittance of the light quantity adjusting element 19 and by APC control (constant control of the irradiated laser light).
- the computer 13 sends a superposition frequency increase command having a superposition frequency fl higher than the superposition frequency fl and a superposition frequency f2 as the superposition frequency control command to the LD driver 17A. (Step S42).
- the LD driver 17A superimposes on the drive current based on the superposition frequency increase command sent from the computer 13 while controlling the drive current based on the power control command sent from the APC circuit 37.
- the superposition frequency fl of the intermittent high-frequency current IoutlO is increased to the superposition frequency f2 corresponding to the superposition frequency increase command.
- the level of the laser beam output from the LD unit 15 and superimposed on the high frequency can be always set to ON (see FIG. 11).
- the reproduction linear velocity of the recording medium 3 is set to a velocity at which the recording signal may pass through the laser beam scanning position during the laser beam off period.
- the recording signal can be read reliably by increasing the superposition frequency of the intermittent high-frequency current to the drive current of the LD unit 15 according to the speed change.
- the laser light can be intermittently turned on and off via the LD unit 15 while maintaining the power of the irradiation laser light on the recording medium 3 substantially constant. Deterioration of the recording layer of the recording medium 3 can be prevented.
- a data recording / reproducing system according to an eighth embodiment of the present invention will be described with reference to the drawings.
- the hardware components of the data recording / reproducing system according to the eighth embodiment are substantially the same as the hardware configuration of the data recording / reproducing system 1A according to the fifth embodiment, and therefore the same reference numerals are used. Therefore, the explanation is omitted or simplified.
- the computer 13 when reproducing the recorded data recorded on the recording track of the recording medium 3, the computer 13 is loaded with at least one loaded into the second memory 13b.
- the process shown in FIG. 15 is executed instead of the process shown in FIG. In this embodiment, the process shown in FIG. 15 is executed for each ECC block of recording data to be reproduced.
- the computer 13 executes a process equivalent to steps S50 and S51 shown in FIG.
- the computer 13 executes the recording medium reproduction process with the light transmittance of the light quantity adjustment element 19 set to the initial ratio of 100% (step S50), and then executes the linear velocity determination process. (Step S51).
- step S51 If the result of determination in step S51 is YES, that is, if the monitor linear velocity is greater than or equal to the threshold velocity, the computer 13 determines that the recording signal may be unreadable by the laser beam, and step In S52, an error rate is obtained as a reproduction characteristic based on the transmitted reproduction data of the ECC block, and it is determined whether or not the obtained error rate is equal to or greater than a predetermined threshold value.
- step S52 determines that the corresponding ECC block has become difficult to reproduce and proceeds to step S60. .
- step S60 the computer 13 performs the APC control as in step S3 shown in FIG. 3, that is, the LC driver while maintaining the power of the irradiation laser light on the recording medium 3 substantially constant.
- the voltage applied to the light amount adjusting element 19 is controlled via 38 to reduce the light transmittance of the light amount adjusting element 19 to a predetermined value (for example, 50%).
- the emission power of the laser light output from the LD unit 15 is increased by reducing the light transmittance of the light quantity adjusting element 19 and by APC control (constant control of the irradiated laser light).
- step S53 the computer 13 sends, as the superposed frequency control command, a superposed frequency increase command having the superposed frequency fl higher than the superposed frequency fl and the frequency f2 as the superposed frequency.
- the LD driver 17A superimposes on the drive current based on the superposition frequency increase command sent from the computer 13 while controlling the drive current based on the power control command sent from the APC circuit 37.
- the superposition frequency fl of the intermittent high-frequency current IoutlO is increased to the superposition frequency f2 corresponding to the superposition frequency increase command.
- the level of the laser beam output from the LD unit 15 and superimposed on the high frequency can be always set to ON (see FIG. 11).
- the reproduction linear velocity of the recording medium 3 is set to a velocity at which the edge of the recording signal may pass through the laser beam scanning position during the laser beam off period.
- the light transmittance of the light amount adjusting element 19 can be reduced while the laser beam irradiation power on the recording medium 3 is maintained substantially constant even when the error rate is equal to or higher than a predetermined threshold value indicating that reproduction is difficult.
- the superposition frequency of the intermittent high-frequency current with respect to the drive current of the LD unit 15 can be increased according to the speed change while increasing the laser beam emission power.
- the laser beam emission power is increased only when the error rate of the data to be reproduced (ECC block) is equal to or higher than a predetermined value. An increase and an increase in current consumption can be suppressed.
- the LD driver 17A uses the superposition frequency of the intermittent high frequency current superimposed on the drive current of the LD unit 15.
- the present invention is not limited to this configuration.
- the computer 13 includes an LD driver 17A and an LD.
- Data representing the current attenuation frequency characteristic (for example, the current attenuation frequency characteristic of the wiring between the LD driver 17A and the LD unit 15) related to current transfer between the units 15 is stored in the memory 13a in advance.
- step S42A corresponding to step S42 of FIG. 10
- the computer 13 also applies the LD driver 17 A force to the LD based on the superimposed frequency rise (fl ⁇ f2) as shown in FIG.
- the amount of current attenuation during current transfer to unit 15 is obtained from the current attenuation frequency characteristic data stored in memory 13a.
- step S4 2B the computer 13 performs a correction current for canceling the calculated attenuation of the current in addition to the superposition frequency increase command having the superposition frequency fl higher than the superposition frequency fl! Send a correction command indicating the amount to the LD driver 17A.
- the LD driver 17A superimposes on the drive current based on the superimposed frequency increase command sent from the computer 13 while controlling the drive current based on the power control command sent from the APC circuit 37.
- the superposition frequency fl of the intermittent high-frequency current IoutlO is increased to f2 corresponding to the superposition frequency increase command, and the amplitude of the intermittent high-frequency current IoutlO is increased by the amount of correction current in the correction command.
- steps S42A and S42B can also be performed in processing equivalent to step S42 in other embodiments.
- the PI in each ECC block is used as a reproduction characteristic serving as an index for evaluating the reproduction data obtained by the recording / reproduction data processing unit 11 and the computer 13.
- the error rate is used, the present invention is not limited to this configuration, and various data can be used as long as it serves as the reproduction data evaluation index. For example, jitter representing the rate of change between the reproduced data and the clock from which the reproduced data power is also extracted can be used as the reproduction characteristic.
- the control processing of the light amount adjusting element 19 in the optical pickup unit 5, the control processing of the power adjusting unit 7, the control processing of the servo driver 9 are performed.
- the present invention is not limited to the above configuration. For example, it can be performed by using two or more computers.
- the superimposition amount setting function F1 and the superposition frequency setting function F2 in the LD driver are based on, for example, a program loaded from the outside (computer or the like). It is also possible to execute the superimposition amount setting process and the superimposition frequency setting process by a computer circuit such as a microcomputer built in the driver.
- the computer 13 when the monitored linear velocity is less than the threshold velocity corresponding to the shortest mark length, the computer 13 can read the recording signal with the laser beam.
- the power determined to be The present invention is not limited to this configuration.
- the computer 13 can always monitor the current playback linear velocity via the servo driver 9 during playback.
- the playback linear velocity increases toward the outer periphery of the recording medium 3 and reaches a threshold speed (for example, 4 ⁇ ) corresponding to 3T, which is the shortest run length.
- the computer 13 detects the increase of the reproduction linear velocity above the threshold speed and performs the above-described processes (light transmittance reduction and superposition amount reduction processing, superposition amount reduction processing, light transmittance reduction and superposition frequency increase).
- a threshold speed for example, 4 ⁇
- the computer 13 detects the increase of the reproduction linear velocity above the threshold speed and performs the above-described processes (light transmittance reduction and superposition amount reduction processing, superposition amount reduction processing, light transmittance reduction and superposition frequency increase).
- the monitor diode is arranged on the optical path of the knock side laser beam emitted from the surface opposite to the LD unit output end in the LD unit package, and the back side laser is provided.
- the present invention is not limited to this configuration.
- it may be configured to constantly monitor the power of a part of the laser beam that has passed through the beam splitter 21 shown in FIG. 2 and has passed through the start-up mirror 23.
- the light amount adjusting element 19 and the objective lens It is also possible to arrange it so that it is arranged on the optical path between the optical system 27 and the optical path branched from the optical system between them, and the reflected light on the corresponding optical path is monitored.
- the present invention is not limited to the above-described embodiments and modifications, and can be implemented with various modifications within the scope belonging to the present invention.
Abstract
Description
Claims
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2008522461A JP4717925B2 (ja) | 2006-06-20 | 2007-06-19 | 光記録再生方法およびシステム、ならびにプログラム |
US12/305,828 US8068391B2 (en) | 2006-06-20 | 2007-06-19 | Optical recording/reproducing method, system, and program |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2006170661 | 2006-06-20 | ||
JP2006-170661 | 2006-06-20 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2007148669A1 true WO2007148669A1 (ja) | 2007-12-27 |
Family
ID=38833411
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/JP2007/062269 WO2007148669A1 (ja) | 2006-06-20 | 2007-06-19 | 光記録再生方法およびシステム、ならびにプログラム |
Country Status (3)
Country | Link |
---|---|
US (1) | US8068391B2 (ja) |
JP (1) | JP4717925B2 (ja) |
WO (1) | WO2007148669A1 (ja) |
Families Citing this family (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2011134407A (ja) * | 2009-12-25 | 2011-07-07 | Hitachi-Lg Data Storage Inc | 光ディスク装置及びディスク判別方法 |
JP2011134409A (ja) * | 2009-12-25 | 2011-07-07 | Hitachi-Lg Data Storage Inc | 光ディスク装置及び光ディスク再生方法 |
JP2011134414A (ja) * | 2009-12-25 | 2011-07-07 | Hitachi-Lg Data Storage Inc | 光ディスク装置及び光ディスク装置におけるデータ再生方法 |
JP2014086107A (ja) * | 2012-10-23 | 2014-05-12 | Funai Electric Co Ltd | 光ディスク装置、及び光ディスクの再生方法 |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS62119743A (ja) * | 1985-11-20 | 1987-06-01 | Hitachi Ltd | 光情報処理装置 |
WO2007043406A1 (ja) * | 2005-10-04 | 2007-04-19 | Matsushita Electric Industrial Co., Ltd. | 光ディスクドライブ装置、及びそれを用いた光ディスクの再生方法 |
JP2007134003A (ja) * | 2005-11-14 | 2007-05-31 | Matsushita Electric Ind Co Ltd | 光ディスク装置 |
JP2007149234A (ja) * | 2005-11-29 | 2007-06-14 | Hitachi Ltd | 光ディスク装置及び光ディスク再生方法 |
Family Cites Families (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH0817065A (ja) | 1994-06-30 | 1996-01-19 | Sony Corp | 光ピックアップ装置 |
JP2001056953A (ja) * | 1999-08-10 | 2001-02-27 | Fujitsu Ltd | 情報記憶装置 |
JP2002260272A (ja) | 2001-02-28 | 2002-09-13 | Sony Corp | 光ヘッド、記録再生装置、及び光結合効率可変素子 |
JP4240883B2 (ja) * | 2001-12-27 | 2009-03-18 | ソニー株式会社 | 光ヘッド及び光記録媒体駆動装置 |
CN1326132C (zh) | 2002-10-28 | 2007-07-11 | 松下电器产业株式会社 | 半导体激光驱动装置、光学头装置以及光信息处理装置 |
JP2005346823A (ja) | 2004-06-02 | 2005-12-15 | Sharp Corp | 光ピックアップおよびその駆動方法 |
JP2006155698A (ja) * | 2004-11-26 | 2006-06-15 | Hitachi Ltd | 光記録再生装置 |
-
2007
- 2007-06-19 WO PCT/JP2007/062269 patent/WO2007148669A1/ja active Application Filing
- 2007-06-19 JP JP2008522461A patent/JP4717925B2/ja not_active Expired - Fee Related
- 2007-06-19 US US12/305,828 patent/US8068391B2/en not_active Expired - Fee Related
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS62119743A (ja) * | 1985-11-20 | 1987-06-01 | Hitachi Ltd | 光情報処理装置 |
WO2007043406A1 (ja) * | 2005-10-04 | 2007-04-19 | Matsushita Electric Industrial Co., Ltd. | 光ディスクドライブ装置、及びそれを用いた光ディスクの再生方法 |
JP2007134003A (ja) * | 2005-11-14 | 2007-05-31 | Matsushita Electric Ind Co Ltd | 光ディスク装置 |
JP2007149234A (ja) * | 2005-11-29 | 2007-06-14 | Hitachi Ltd | 光ディスク装置及び光ディスク再生方法 |
Also Published As
Publication number | Publication date |
---|---|
US20100232271A1 (en) | 2010-09-16 |
JP4717925B2 (ja) | 2011-07-06 |
US8068391B2 (en) | 2011-11-29 |
JPWO2007148669A1 (ja) | 2009-11-19 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
JP4420920B2 (ja) | 光記録媒体駆動装置、フォーカスオン方法 | |
JP4717925B2 (ja) | 光記録再生方法およびシステム、ならびにプログラム | |
JP2006099928A (ja) | 光ディスク装置、フォーカスバイアス及び球面収差補正値調整方法 | |
JP2010055678A (ja) | 光ディスク装置 | |
JP2008299957A (ja) | 光ディスク装置、及び光ディスク装置の制御方法 | |
JP2007172770A (ja) | 光ディスク装置 | |
JP4493716B2 (ja) | 光記録再生方法およびシステム、ならびにプログラム | |
JP4264653B2 (ja) | 光ディスク装置、フォーカスバイアス及び球面収差補正値調整方法 | |
JP4938085B2 (ja) | 記録装置及び方法、並びにコンピュータプログラム | |
JP4493722B2 (ja) | 光記録再生方法およびシステム、ならびにプログラム | |
JP4493051B2 (ja) | 情報記録媒体、情報記録装置及び情報記録方法、並びにコンピュータプログラム | |
JP2006185498A (ja) | 光ピックアップ | |
WO2007148387A1 (ja) | 光記録再生方法およびシステム、ならびにプログラム | |
WO2007148386A1 (ja) | 光記録再生方法およびシステム、ならびにプログラム | |
JP2006294158A (ja) | 情報記録/再生方法及び光ディスク装置 | |
JP2004288251A (ja) | 光ディスク記録再生装置 | |
WO2007148668A1 (ja) | 光記録情報再生方法および装置、ならびに光記録情報再生用プログラム | |
WO2007148670A1 (ja) | 光記録情報再生方法および装置、ならびに光記録情報再生用プログラム | |
JP2005310329A (ja) | 光記録媒体、再生装置、トラッキングサーボ方法 | |
JP2013033574A (ja) | 光ディスク装置、及び光ディスク装置における記録パワーの制御方法 | |
JP2005310231A (ja) | 信号処理装置及び光ディスク装置 | |
JP2011065696A (ja) | 光ディスク並びに光ディスク装置及び記録方法 | |
JP2008204550A (ja) | 記録装置、光ピックアップ装置 | |
JPWO2005122151A1 (ja) | 情報記録装置及び方法、並びにコンピュータプログラム | |
JP2009037659A (ja) | 光ディスク装置及び光ディスクの再生方法 |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
121 | Ep: the epo has been informed by wipo that ep was designated in this application |
Ref document number: 07745491 Country of ref document: EP Kind code of ref document: A1 |
|
WWE | Wipo information: entry into national phase |
Ref document number: 2008522461 Country of ref document: JP |
|
WWE | Wipo information: entry into national phase |
Ref document number: 12305828 Country of ref document: US |
|
NENP | Non-entry into the national phase |
Ref country code: DE |
|
122 | Ep: pct application non-entry in european phase |
Ref document number: 07745491 Country of ref document: EP Kind code of ref document: A1 |