CN116917990A - Information recording/reproducing apparatus and information recording/reproducing method - Google Patents
Information recording/reproducing apparatus and information recording/reproducing method Download PDFInfo
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- CN116917990A CN116917990A CN202180094598.3A CN202180094598A CN116917990A CN 116917990 A CN116917990 A CN 116917990A CN 202180094598 A CN202180094598 A CN 202180094598A CN 116917990 A CN116917990 A CN 116917990A
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- information recording
- track
- recording
- reproduction
- reproducing
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- 238000000034 method Methods 0.000 title claims description 24
- 230000003287 optical effect Effects 0.000 claims abstract description 28
- 230000001678 irradiating effect Effects 0.000 claims 1
- 238000001514 detection method Methods 0.000 description 16
- 230000004044 response Effects 0.000 description 16
- 238000010586 diagram Methods 0.000 description 11
- 238000005070 sampling Methods 0.000 description 6
- 239000004065 semiconductor Substances 0.000 description 3
- 230000005540 biological transmission Effects 0.000 description 2
- 238000007476 Maximum Likelihood Methods 0.000 description 1
- 230000003044 adaptive effect Effects 0.000 description 1
- 230000010485 coping Effects 0.000 description 1
- 238000000280 densification Methods 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 238000010606 normalization Methods 0.000 description 1
- 230000011218 segmentation Effects 0.000 description 1
Classifications
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B20/00—Signal processing not specific to the method of recording or reproducing; Circuits therefor
- G11B20/10—Digital recording or reproducing
-
- 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
-
- 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
- G11B7/08—Disposition or mounting of heads or light sources relatively to record carriers
-
- 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
- G11B7/13—Optical detectors therefor
- G11B7/131—Arrangement of detectors in a multiple array
Abstract
By determining whether a track is recorded or not by using the correlation coefficient between channels of the divided reproduction optical detector, even in a narrow track state, the recorded or not state can be accurately determined.
Description
Technical Field
The present disclosure relates to an information recording/reproducing apparatus and an information recording/reproducing method capable of accurately discriminating a recorded state/unrecorded state for more stably realizing high-density recording with respect to an information recording medium having an information recording surface capable of optically recording information.
Background
Conventionally, as information recording media for storing video, data, and the like, DVD, blu-ray (registered trademark) Disc (hereinafter BD), and the like have been used. Recently, BD is also used for data archiving for long-term storage of important data by a highly reliable system. Data archiving is a commodity that is mainly sold for business use, and further densification is required to enable more data to be saved.
As a technique for improving the recording capacity, there are a technique for improving the track density and a technique for improving the linear density.
As a technique for increasing the track density, there is a land (inter-groove) -groove (groove) recording/reproducing technique. This technique has been used for DVD-RAM to increase track density by recording existing data recorded only in grooves or lands in both grooves and lands. Further, a crosstalk cancellation technique for reducing crosstalk components from adjacent tracks is disclosed (see patent document 1). In this technique, reflected light from an optical disk is divided into a plurality of areas and detected, and a plurality of detected reproduction signals are synthesized into a reproduction signal having a predetermined frequency characteristic using a waveform equalizer, and crosstalk components are reduced. By this technique, the track density can be further improved.
As a technique for increasing the linear density, a PRML (Partial Response Maximum Likelihood) signal processing technique is generally used. In addition, PLL (Phase Locked Loop) technology capable of coping with high linear density is also used in order to stably exhibit reproduction performance by the PRML signal processing technology (see patent document 2).
By these techniques, the recording capacity of the optical disc is improved.
In order to store data in an optical disc, it is necessary to distinguish between a recorded track and an unrecorded track, and for example, in patent document 3, the recorded track and the unrecorded track are distinguished by comparing the amplitude of a total light quantity signal proportional to the intensity of reflected light from the optical disc with a threshold value.
However, in this technique, in the case of an optical disc in which the track density is increased, there is a problem in that crosstalk components from adjacent tracks are large, and even if a discrimination target track is in an unrecorded state, since crosstalk from the adjacent tracks can see a large reproduction signal amplitude, the unrecorded track is discriminated as recorded.
Prior art literature
Patent literature
Patent document 1: international publication No. 2014/057674
Patent document 2: international publication No. 2015/107573
Patent document 3: japanese patent application laid-open No. 2013-143175
Disclosure of Invention
The present disclosure provides an information recording/reproducing apparatus and an information recording/reproducing method capable of discriminating between a recorded track and an unrecorded track with respect to an optical disk having an increased track density.
An information recording/reproducing apparatus capable of recording/reproducing information on/from a track of an information recording medium, the information recording/reproducing apparatus comprising: an optical head that irradiates the track with a light beam and outputs a reproduction signal based on the detected reflected light; and a recording/non-recording discriminating circuit for discriminating whether the track is in a recorded state or in a non-recorded state based on the reproduction signal.
An information recording/reproducing apparatus of the present disclosure is capable of recording/reproducing information on/from a track of an information recording medium, and includes: an optical head that irradiates the track with a light beam and outputs a reproduction signal based on the detected reflected light; a decoding circuit decoding the recorded information from the reproduction signal; and a recording/non-recording discriminating circuit for discriminating whether the track is in a recorded state or in a non-recorded state.
The information recording/reproducing apparatus of the present disclosure is effective in accurately discriminating whether a track is in a recorded state or an unrecorded state even for an optical disk having an increased track density.
Drawings
Fig. 1 is a diagram showing an information recording/reproducing apparatus according to embodiment 1.
Fig. 2 is a diagram showing a structure of an optical head in embodiment 1.
Fig. 3 is a block diagram showing the configuration of a playback signal decoding circuit and a recording/non-recording determiner in embodiment 1.
Fig. 4 is a diagram showing an impulse response waveform of recorded data of a track to be discriminated from a reproduction waveform.
Fig. 5 is a diagram showing an impulse response waveform of recorded data with an outer track in a reproduction waveform.
Fig. 6 is a diagram showing an impulse response waveform of recorded data with an inner track in a reproduction waveform.
Fig. 7 is a diagram showing the correlation coefficient detection values for each of the recorded and unrecorded states.
Detailed Description
Hereinafter, embodiments will be described in detail with reference to the drawings as appropriate. In this case, unnecessary detailed description may be omitted. For example, detailed descriptions of known matters and repeated descriptions of substantially the same structure may be omitted. This is to avoid the following description becoming redundant unnecessarily, as will be readily appreciated by those skilled in the art.
In addition, the drawings and the following description are provided for a full understanding of the present disclosure by those skilled in the art, and are not intended to limit the subject matter recited in the claims.
(embodiment 1)
Fig. 1 is a block diagram showing the structure of an information recording/reproducing apparatus 100 according to the present embodiment. The information recording/reproducing apparatus 100 includes: an information recording medium 101 (e.g., an optical disk), an optical head 102, a laser driving circuit 107, a data modulating circuit 108, an error correction encoding circuit 109, a reproduction signal decoding circuit 103, a data demodulating circuit 104, an error correction decoding circuit 105, a system controller 110, and a recording/non-recording discriminating circuit 106.
The information recording/reproducing device 100 records data on the information recording medium 101 in response to a recording request from the host 111. The information recording medium 101 is formed with a track in a spiral shape from the inner circumference to the outer circumference. The tracks include groove tracks formed of grooves (grooves), land tracks formed between adjacent groove tracks. Data is recorded on any one of the groove tracks and the land tracks.
The error correction encoding circuit 109 adds a parity for error correction to the recorded data received from the host 111.
The data modulation circuit 108 generates a modulation signal for modulating the recorded data including the parity added by the error correction coding circuit 109 according to a predetermined modulation rule.
The laser driving circuit 107 converts the modulation signal generated by the data modulation circuit into an optical pulse, drives the optical head 102, and irradiates a light beam based on the optical pulse. A mark is formed on the information recording medium 101 by heat of the irradiated light beam. In this way, data is recorded in the information recording medium 101.
On the other hand, the information recording/reproducing apparatus 100 reproduces data recorded on the information recording medium 101 in response to a reproduction request from the host 111.
The optical head 102 irradiates a track of the information recording medium 101 with a light beam, and detects reflected light from the information recording medium 101. The optical head 102 outputs an electric signal generated based on the detected reflected light as a reproduction signal.
The reproduction signal decoding circuit 103 decodes the reproduction signal output from the optical head 102 and generates a decoded signal. Specifically, the reproduction signal decoding circuit 103 generates a decoded signal by PRML signal processing. That is, the playback signal decoding circuit 103 compares the playback signal with the expected value waveform, selects the expected value waveform closest to the playback signal, and outputs data based on the expected value waveform as a decoded signal.
The data demodulation circuit 104 demodulates the recorded data from the decoded signal generated by the reproduced signal decoding circuit 103 according to a predetermined modulation rule.
The error correction decoding circuit 105 corrects errors of the recorded data demodulated by the data demodulation circuit 104, and restores the correct recorded data.
The record/non-record discriminating circuit 106 discriminates whether the track on the information recording medium 101 is in a recorded state or in a non-recorded state.
Fig. 2 is a diagram showing the structure of the optical head 102. As shown in fig. 2, the optical head 102 includes: an objective lens 201, a laser lens 202, a dividing element 203, a photodetector 205 for reproduction, and a blue semiconductor laser 206.
The blue semiconductor laser 206 emits a light beam having a wavelength of 405 nm. The light beam is reflected by the laser lens 202, condensed by the objective lens 201, and irradiated onto the track of the information recording medium 101.
The reflected light reflected and diffracted on the track of the information recording medium 101 is transmitted in the order of the objective lens 201 and the laser lens 202. The dividing element 203 splits the input light into a plurality of directions. The reproduction photodetectors 205 each receive the light split by the splitting element 203.
The dividing element 203 functions as a diffraction grating by forming fine grooves on the surface. The dividing element 203 has a dividing pattern 204 that divides an area into which reflected light from the information recording medium 101 enters into 6 areas Ch1 to Ch6. The reflected light transmitted through each region is split into different directions by the diffraction grating. The reproduction photodetector 205 has 6 light receiving areas for receiving the 6 reflected lights divided by the respective areas of the transmission dividing element 203. The reproduction photodetector 205 generates 6 reproduction signals based on the amounts of light received by the respective light receiving areas. Both ends in the recording line direction (track direction) of the division pattern 204 are divided into an area Ch5 and an area Ch6, respectively. The divided pattern 204 is divided into a region Ch1 and a region Ch2 at the center in the radial direction, which is the direction perpendicular to the recording line direction, and into a region Ch3 and a region Ch4 at both ends. The region Ch1 and the region Ch2 are disposed on both sides of the center of the dividing element 203 in the radial direction. In other words, the areas Ch1 and Ch2 are one area and the other area that divide the central portion of the dividing element 203 to the left and right with respect to the recording line direction. The region Ch3 is disposed adjacent to the region Ch1 on the outer side of the region Ch1 in the radial direction. The region Ch4 is disposed adjacent to the region Ch2 on the outer side of the region Ch2 in the radial direction. In the following description, a reproduction signal outputted by receiving light transmitted through the region Ch1 in the light receiving region of the reproduction light detector 205 is referred to as a reproduction signal of the region Ch 1. The same applies to reproduction signals of other areas.
The 6 reproduction signals generated by the reproduction photodetector 205 are synthesized by performing a predetermined operation on each of the reproduction signals in the reproduction signal decoding circuit 103, thereby reducing crosstalk components included in the reproduction signals, and decoding modulated signals recorded on the track of the target to generate decoded signals.
Fig. 3 is a block diagram showing the configuration of the playback signal decoding circuit 103 and the record/non-record determination circuit 106. As shown in fig. 3, the playback signal decoding circuit 103 includes: AGC (Auto Gain Control, automatic gain control) 301, a/D converter 302, fir (Finite Impulse Response ) filter circuit 303, addition circuit 304, LMS (Least Mean Square ) circuit 306, viterbi decoding circuit 305, phase error detection circuit 307, loop filter circuit 308, and VCO (Voltage Controlled oscillator ) circuit 309. The AGC301, the a/D converter 302, and the FIR filter circuit 303 are each composed of 6 pieces according to the number of reproduction signals output from the reproduction photodetector 205.
The AGC301 adjusts the amplitudes of the 6 reproduction signals so as to be the target amplitudes of the reproduction signals outputted from the a/D converter 302, respectively.
The a/D converter 302 converts each of the 6 reproduction signals generated by the reproduction photodetector 205 into a digital signal.
The FIR filter circuits 303 perform waveform equalization on the 6 digital signals output from the a/D converters 302, respectively.
The adder circuit 304 adds up the 6 digital signals output from the FIR filter circuit 303 and synthesizes one digital signal.
The viterbi decoding circuit 305 decodes the recorded modulated signal from the synthesized digital signal by viterbi decoding, and outputs a decoded signal.
The LMS circuit 306 controls the respective tap coefficients of the FIR filter circuit 303. The LMS circuit 306 controls the tap coefficients of the respective FIR filter circuits 303 so that the error between the expected value waveform obtained from the decoded signal by the viterbi decoding circuit 305 and the digital signal synthesized by the adder circuit 304 becomes small.
The FIR filter circuit 303 operates as an adaptive equalization filter. Thus, the reproduced signal decoding circuit 103 synthesizes waveform equalization from 6 digital signals into a digital signal that reduces crosstalk components and has frequency characteristics equal to the expected value waveform.
The phase error detection circuit 307 detects a phase error value with respect to the sampling phase of the ideal digital signal in the viterbi decoding circuit 305 from the digital signal and the decoded signal synthesized by the adder circuit 304. Loop filter circuit 308 converts the detected phase error value into a control signal that controls the frequency of the sampling clock.
The VCO circuit 309 generates a sampling clock having a frequency corresponding to the control signal output from the loop filter circuit 308. The generated sampling clock is used as a clock indicating the sampling timing of the a/D converter 302 and the operation timing of the subsequent circuits.
With the above configuration, the playback signal decoding circuit 103 performs reduction of noise components including crosstalk components from the digital signal, correction of frequency characteristics of waveforms, and correction of sampling phases so as to be the conditions most suitable for the decoding process of the viterbi decoding circuit 305.
The recording/non-recording determination circuit 106 includes correlation coefficient detection circuits 310, 311, 312, 313 and a determination circuit 314.
The correlation coefficient detection circuit 310 detects the correlation coefficient between the reproduction signal of the region Ch1 and the reproduction signal of the region Ch2 in the division pattern 204 of the division element 203.
The correlation coefficient detection circuit 311 detects the correlation coefficient between the reproduction signal of the region Ch3 and the reproduction signal of the region Ch4 in the division pattern 204 of the division element 203.
The correlation coefficient detection circuit 312 detects the correlation coefficient between the reproduction signal of the region Ch1 and the reproduction signal of the region Ch4 in the division pattern 204 of the division element 203.
The correlation coefficient detection circuit 313 detects the mutual correlation coefficient of the reproduction signal of the region Ch2 and the reproduction signal of the region Ch3 in the division pattern 204 of the division element 203.
The determination circuit 314 compares the correlation coefficients detected by the correlation coefficient detection circuits 310, 311, 312, 313 with a threshold value to determine whether the track to be determined is recorded or unrecorded.
Fig. 4 is a diagram showing an impulse response waveform of recorded data of a discrimination target track included in a reproduction waveform of a discrimination target track recorded or unrecorded. Fig. 5 is an impulse response waveform of recorded data for an outer track included in a reproduction waveform of a discrimination target track recorded and unrecorded as a crosstalk component. Fig. 6 is an impulse response waveform of recorded data for an inner track included in a reproduction waveform of a discrimination target track recorded and unrecorded as a crosstalk component.
The impulse response waveform can be obtained by performing fourier transform on the recorded data and the reproduced waveform, dividing the result of the fourier transform by the result of the fourier transform, thereby obtaining the transmission characteristics from the recorded data to the reproduced waveform, and further performing inverse fourier transform on the division result.
As is clear from fig. 4 to 6, the reproduction signals of the areas Ch1 to Ch6 are in-phase relation with respect to the recorded data in the impulse response of the recorded data of the discrimination target track, the reproduction signals of the areas Ch1 and Ch4 are in anti-phase relation with respect to the recorded data of the outer track as the crosstalk component, and the reproduction signals of the areas Ch2 and Ch3 are in anti-phase relation with respect to the impulse response of the recorded data of the inner track as the crosstalk component.
Fig. 7 shows detection values of the correlation coefficient detection circuits 310, 311, 312, 313 in a state where the discrimination target track, the outer track, and the inner track are actually recorded (indicated by a symbol "Σ") or unrecorded (indicated by a symbol "-").
When the track to be discriminated is recorded, the amplitude of the impulse response shown in fig. 4 is larger than the amplitude of the impulse response of the crosstalk components shown in fig. 5 and 6, and the components of the impulse response shown in fig. 4 in-phase relation are dominant, so that the reproduced signals have a positive correlation. When the track to be discriminated is not recorded, one or both of the inner track and the outer track are recorded, the reproduction signals between Ch are mainly in the inverse relationship, and therefore it can be confirmed that the reproduction signals obtain both of the correlation on the negative side only, the correlation on the positive side, and the correlation on the negative side. In addition, when all of the discrimination target track, the inner track, and the outer track are unrecorded, the reproduction signal does not include a noise component, and therefore it is possible to confirm that the reproduction signal obtains both the positive-side correlation and the negative-side correlation.
Further, since the correlation coefficient is an index of normalization, it becomes an index that is hardly affected by the AGC301 in the reproduced signal decoding circuit 103.
According to fig. 7, the detection values of the correlation coefficient detection circuits 310, 311, 312, 313 are subjected to threshold value determination by the determination circuit 314, so that the recorded and unrecorded states of the determination target track can be distinguished. Specifically, even if there is a negative correlation, it is determined that the determination target track is unrecorded. When all of the 4 correlations are positive, it is determined that the determination target track is recorded when the correlation has a specific value (for example, 0.25) or more in order to avoid erroneous detection.
An information recording/reproducing apparatus and an information recording/reproducing method can be provided, which can perform stable discrimination between recorded tracks and unrecorded tracks on an optical disk having an increased track density by using a track record/unrecorded discrimination signal obtained from a discrimination circuit 314.
Industrial applicability
The present disclosure can be applied to an information recording/reproducing apparatus that performs recording/reproducing of data on/from an optical disc.
Symbol description-
100 information recording/reproducing apparatus
101 information recording medium
102 optical head
103 reproduction signal decoding circuit
104 data demodulation circuit
105 error correction decoding circuit
106 record/non-record discriminating circuit
107 laser driving circuit
108 data modulation circuit
109 error correction coding circuit
110 system controller
111 host
201 objective lens
202 laser lens
203 dividing element
204 segmentation pattern
205 photodetector for reproduction
206 blue semiconductor laser
301AGC
302A/D converter
303FIR filter circuit
304 adder circuit
305 viterbi decoding circuit
306LMS circuit
307 phase error detection circuit
308 loop filter circuit
309VCO circuit
310. 311, 312, 313 correlation coefficient detection circuit
314 discrimination circuitry.
Claims (6)
1. An information recording/reproducing apparatus capable of recording/reproducing information on/from a track of an information recording medium, the information recording/reproducing apparatus comprising:
an optical head that irradiates the track with a light beam and outputs a reproduction signal based on the detected reflected light; and
and a recording/non-recording discriminating circuit for discriminating whether the track is in a recorded state or in a non-recorded state based on the reproduction signal.
2. The information recording and reproducing apparatus of claim 1, wherein,
the optical head is provided with:
a dividing element for receiving the reflected light and generating a plurality of diffracted lights through a plurality of diffraction regions; and
a photodetector that receives the plurality of diffracted lights of the dividing element, outputs a plurality of reproduction signals based on the respective light amounts of the received plurality of diffracted lights,
the recording/non-recording discriminating circuit calculates a correlation coefficient between the plurality of reproduction signals, and discriminates whether the track is in a recorded state or in a non-recorded state based on the correlation coefficient.
3. The information recording and reproducing apparatus of claim 2, wherein,
the recording/non-recording discriminating circuit discriminates that the track is in a recorded state when all of the calculated correlation coefficients are positive.
4. An information recording/reproducing method capable of recording/reproducing information on/from a track of an information recording medium by an information recording/reproducing apparatus,
the information recording/reproducing device is provided with:
an optical head for irradiating a track of the information recording medium with a light beam and outputting a reproduction signal based on the detected reflected light,
in the information recording and reproducing method of the present invention,
and judging whether the track is in a recorded state or an unrecorded state according to the reproduction signal.
5. The information recording/reproducing method of claim 4, wherein,
the optical head is provided with:
a dividing element for receiving the reflected light and generating a plurality of diffracted lights through a plurality of diffraction regions; and
a photodetector that receives the plurality of diffracted lights of the dividing element, outputs a plurality of reproduction signals based on the respective light amounts of the received plurality of diffracted lights,
in the information recording and reproducing method of the present invention,
calculating a correlation coefficient between the plurality of reproduction signals,
and judging whether the track is in a recorded state or an unrecorded state according to the correlation coefficient.
6. The information recording/reproducing method of claim 5, wherein,
when all of the calculated correlation coefficients are positive, it is determined that the track is in a recorded state.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2021-041964 | 2021-03-16 | ||
| JP2021041964 | 2021-03-16 | ||
| PCT/JP2021/030296 WO2022195912A1 (en) | 2021-03-16 | 2021-08-19 | Information recording/reproducing device, and information recording/reproducing method |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN116917990A true CN116917990A (en) | 2023-10-20 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202180094598.3A Pending CN116917990A (en) | 2021-03-16 | 2021-08-19 | Information recording/reproducing apparatus and information recording/reproducing method |
Country Status (3)
| Country | Link |
|---|---|
| JP (1) | JPWO2022195912A1 (en) |
| CN (1) | CN116917990A (en) |
| WO (1) | WO2022195912A1 (en) |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2009295247A (en) * | 2008-06-06 | 2009-12-17 | Sony Corp | Optical disk drive and signal correction method |
| JP5055411B2 (en) * | 2010-08-23 | 2012-10-24 | 株式会社日立製作所 | Optical disk apparatus and optical disk apparatus adjustment method |
| JP2012128893A (en) * | 2010-12-13 | 2012-07-05 | Hitachi-Lg Data Storage Inc | Optical disk device and control method for reproduction power |
| JP2013218759A (en) * | 2012-04-06 | 2013-10-24 | Funai Electric Co Ltd | Optical disk device and optical disk record presence determination method |
| JP2014035780A (en) * | 2012-08-10 | 2014-02-24 | Hitachi Consumer Electronics Co Ltd | Optical disk device |
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2021
- 2021-08-19 WO PCT/JP2021/030296 patent/WO2022195912A1/en active Application Filing
- 2021-08-19 JP JP2023506713A patent/JPWO2022195912A1/ja active Pending
- 2021-08-19 CN CN202180094598.3A patent/CN116917990A/en active Pending
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| Publication number | Publication date |
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| JPWO2022195912A1 (en) | 2022-09-22 |
| WO2022195912A1 (en) | 2022-09-22 |
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