JP2006277876A - Optical disk device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accurately extract wobbles and auxiliary information recorded by the wobbles. <P>SOLUTION: This optical disk device comprises a photodetection part for outputting first and second detection signals, respectively corresponding to first reflected light from an area including a boundary on the outer periphery side of a track and second reflected light from an area, including a boundary on the inner periphery side of the track; first and second gain adjusters for respectively normalizing and outputting the amplitudes of the first and second detection signals; a balance adjustment part for adjusting the output signals of the first and second gain adjusters so that the ratio of the amplitudes of both becomes the ratio, corresponding to balance adjustment signals and outputting the respective signals after adjustment as the first and second detection signals after balance adjustment; a subtractor for obtaining and outputting the difference between the first and second detection signals after the balance adjustment; an auxiliary information extractor for obtaining the accessory information, on the basis of the output of the subtractor; and a control part for generating and outputting the balance adjustment signals so as to be able to accurately obtain the auxiliary information. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an optical disc apparatus for recording data on an optical disc on which incidental information is recorded by wobble.

  In general, a recordable optical disc is provided with a guide groove (groove) for guiding a light spot during data recording as shown in FIG. 1, and data is recorded along the groove. The groove is wobbled in a predetermined shape in order to generate a reference clock for controlling the rotation of the disk.

  In particular, in optical disks such as DVD + R and DVD + RW, ADIP (Address In Pre-groove) is obtained by wobbling the groove into a shape in which a sine wave and a sine wave whose phase is shifted by 180 degrees are connected to each other. Called address information is recorded as incidental information.

  When extracting the incidental information recorded by the wobble, the first reflected light from the region including one boundary of the track (groove) and the second reflected light from the region including the other boundary of the track are used. A method is widely employed in which, after amplification, wobble signals are obtained from the difference between the amplified signals (referred to as signals TE + and TE−, respectively) and incidental information is extracted.

  When generating the difference signal, the RF residual component increases due to variations in the amplitude and phase of the signal output from the optical pickup, and variations in the gain of the amplifier, resulting in deterioration of the wobble signal and incidental information detection rate. Decrease. In order to avoid this, the signal TE + and the signal TE− are normalized by an AGC (Auto Gain Controller) so that the amplitudes are substantially equal, and then a difference signal is generated, and the obtained difference signal is converted into an LPF (Low There is a method of removing noise through a Pass Filter.

A method for extracting the supplementary information recorded by wobble is disclosed in, for example, Patent Document 1.
Japanese Patent Laid-Open No. 11-161982

  However, the amplitude of the normalized signal varies due to variations in the characteristics of the AGC generated at the time of manufacture, and the RF (radio frequency) residual component cannot be completely removed. Further, attenuation of the RF residual component can be expected by lowering the cutoff frequency Fc of the LPF, but the frequency of the wobble signal of DVD + R and DVD + RW is 817 kHz (for example, other recording optical disks DVD-R and DVD-RAM). Since the frequency band of the RF component is close to the frequency band of the RF component, it is difficult to remove only the RF residual component by setting the cutoff frequency Fc. As a result, the wobble signal is deteriorated and the incidental information detection rate is lowered.

  Further, at the time of data recording, writing is performed with a high-speed pulse according to the laser emission pattern, so that the high frequency residual component is increased as compared with the time of reproduction, which causes further deterioration of the wobble signal and reduction of the incidental information detection rate. As a result, the address information given as the accompanying information cannot be accurately detected. When data is written to an erroneously detected address, data overwrite or blank occurs.

  Therefore, it is necessary to adjust the system for extracting the wobble and the incidental information recorded by the wobble in the optical disk apparatus for each apparatus and each optical disk. In particular, in an optical disk apparatus that performs higher-speed recording, it is necessary to extract wobbles and accompanying information recorded by wobbles more accurately.

  An object of the present invention is to provide an optical disc apparatus capable of more accurately extracting wobbles and incidental information recorded by wobbles.

  In order to solve the above problem, the means of the invention of claim 1 is an optical disc apparatus for extracting incidental information recorded by wobble on a track on the optical disc, and irradiating the track with a light beam. A first reflected light from an element and a region including a boundary on an outer peripheral side of the track and a second reflected light from a region including a boundary on an inner peripheral side of the track are detected, and the first and second A light detection unit that outputs first and second detection signals corresponding to the reflected light, a first gain adjuster that normalizes and outputs the amplitude of the first detection signal, and the second detection signal; The second gain adjuster that normalizes and outputs the output signal of the first gain adjuster and the output signal of the first and second gain adjusters are adjusted so that the ratio of the amplitudes of both is the ratio according to the balance adjustment signal. To adjust each of the adjusted signals. A balance adjustment unit that outputs the first and second detection signals after lance adjustment, and a subtraction that obtains and outputs the difference between the first detection signal after balance adjustment and the second detection signal after balance adjustment A supplementary information extractor for obtaining the supplementary information based on the output of the subtractor, and a controller for generating and outputting the balance adjustment signal so that the supplementary information is accurately obtained. is there.

  According to the first aspect of the invention, the ratio of the amplitudes of the normalized first and second detection signals is set to an appropriate value, and the in-phase signal included in both the first and second detection signals is removed. Therefore, it is possible to accurately detect wobbles and accurately determine incidental information.

  According to a second aspect of the present invention, in the optical disc apparatus according to the first aspect, there is further provided an auxiliary information detection / determination unit that determines whether or not the auxiliary information is correctly obtained by the auxiliary information extractor and outputs the determination result. It is to be prepared.

  According to a third aspect of the present invention, in the optical disc apparatus according to the second aspect, the rate at which the supplementary information is obtained is measured based on the determination result and the measurement result is output as a supplementary information detection rate. A rate measuring device is further provided.

  According to a fourth aspect of the present invention, in the optical disc apparatus according to the third aspect, the control unit obtains the balance adjustment signal so that the incidental information detection rate is increased during reproduction of the recorded disc, and the obtained balance. The adjustment signal is output at the time of data recording.

  According to a fifth aspect of the present invention, in the optical disc apparatus according to the fourth aspect, after the control unit outputs the obtained balance adjustment signal, the balance is adjusted so that the incidental information detection rate is increased during data recording. An adjustment signal is obtained and output.

  According to a sixth aspect of the present invention, in the optical disc apparatus according to the fourth aspect, during data recording, an amplitude difference between the output of the first gain adjuster and the output of the second gain adjuster is detected, An amplitude difference detector for controlling the balance adjustment unit is further provided so that the difference in amplitude is reduced.

  According to a seventh aspect of the present invention, in the optical disc device according to the fourth aspect, a phase difference between the output of the first gain adjuster and the output of the second gain adjuster is detected during data recording, A phase difference detector for controlling the balance adjusting unit is further provided so that the phase difference is reduced.

  According to an eighth aspect of the present invention, in the optical disc apparatus according to the third aspect, the control unit obtains the balance adjustment signal so as to increase the incidental information detection rate during recording in the laser power learning area, and obtains the obtained amount. The obtained balance adjustment signal is output at the time of data recording.

  According to a ninth aspect of the present invention, in the optical disc apparatus according to the eighth aspect, after the control unit outputs the obtained balance adjustment signal, the balance information detection rate is increased during data recording. An adjustment signal is obtained and output.

  According to a tenth aspect of the present invention, in the optical disc device according to the eighth aspect, during data recording, a difference in amplitude between the output of the first gain adjuster and the output of the second gain adjuster is detected, An amplitude difference detector for controlling the balance adjustment unit is further provided so that the difference in amplitude is reduced.

  According to an eleventh aspect of the present invention, in the optical disc device according to the eighth aspect, during data recording, a phase difference between the output of the first gain adjuster and the output of the second gain adjuster is detected, A phase difference detector for controlling the balance adjusting unit is further provided so that the phase difference is reduced.

  According to a twelfth aspect of the present invention, in the optical disc apparatus according to the third aspect, the control unit outputs the balance adjustment signal so that the incidental information detection rate is increased during reproduction of the laser power learning area after laser power learning. The obtained balance adjustment signal is output at the time of data recording.

  According to a thirteenth aspect of the present invention, in the optical disc apparatus according to the twelfth aspect, after the control unit outputs the obtained balance adjustment signal, the balance is set so that the incidental information detection rate is increased during data recording. An adjustment signal is obtained and output.

  According to a fourteenth aspect of the present invention, in the optical disc device according to the twelfth aspect, at the time of data recording, a difference in amplitude between the output of the first gain adjuster and the output of the second gain adjuster is detected, An amplitude difference detector for controlling the balance adjustment unit is further provided so that the difference in amplitude is reduced.

  According to a fifteenth aspect of the present invention, in the optical disc device according to the twelfth aspect, the phase difference between the output of the first gain adjuster and the output of the second gain adjuster is detected during data recording, A phase difference detector for controlling the balance adjusting unit is further provided so that the phase difference is reduced.

  According to the present invention, it is possible to accurately detect incidental information such as address information recorded by wobble and wobble of a track on an optical disc. For this reason, it becomes possible to record on the optical disc at a higher speed.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is an explanatory diagram showing an example of the structure of the recording surface of an optical disc. Data is recorded on information tracks (hereinafter simply referred to as tracks) which are linear regions formed concentrically or spirally on the optical disc. A track is typically a groove or a land. Here, since the optical disk is described as a DVD + R disk or a DVD + RW disk, the track is a groove.

  As shown in FIG. 1, the groove is wobbling (meandering) into a shape in which a sine wave having a predetermined wavelength and a sine wave whose phase is shifted from this sine wave by 180 degrees are connected. In the groove, address information (referred to as ADIP (Address In Pre-groove)) is recorded as incidental information by such wobble.

  FIG. 2 is a block diagram of the optical disc apparatus according to the embodiment of the present invention. The optical disk apparatus of FIG. 1 includes an optical pickup 10, a semiconductor laser control block 22, a servo processing block 24, a central control block 26 as a control unit, and a reproduction signal processing block 30.

  The optical pickup 10 includes a semiconductor laser 11 as a light irradiating element, a semiconductor laser driving block 12, and a light detection unit 14. The optical pickup 10 writes data to the optical disc 2 and reads data from the optical disc 2. The optical disk 2 is rotated by a motor 4. The reproduction signal processing block 30 has an accompanying information extraction block 32 and a data detection block 34.

  The central control block 26 controls the semiconductor laser control block 22, the servo processing block 24, the incidental information extraction block 32, the data detection block 34, and the like. The central control block 26 can also be controlled from outside the optical disk apparatus of FIG.

  The semiconductor laser control block 22 sets the output power of the semiconductor laser 11 in the semiconductor laser drive block 12. The semiconductor laser drive block 12 determines the drive current of the semiconductor laser 11 based on the set output power, and drives the semiconductor laser 11. The servo processing block 24 controls the movement of the optical pickup 10. The reproduction signal processing block 30 processes the signal output from the light detection unit 14.

  FIG. 3A is a plan view of the optical disk of FIG. FIG. 3B is a block diagram illustrating a configuration of the light detection unit 14 of FIG. The groove has an outer peripheral side boundary S1 and an inner peripheral side boundary S2. The light detection unit 14 includes a light detection element 15, amplifiers 16A, 16B, 16C, and 16D, and addition circuits 17A, 17B, 17C, and 17D.

  The semiconductor laser 11 irradiates the optical disc 2 with a light beam with a predetermined power, and forms a light spot on a track (here, a groove) of the optical disc 2 as shown in FIG. 1 or FIG. The irradiated light beam is reflected by the optical disc 2. This reflected light is detected by the light detection element 15 of the light detection unit 14 (see FIG. 3B).

  The light detection element 15 has at least two light receiving portions arranged so as to be aligned in a direction (that is, a radial direction of the disk) perpendicular to the groove direction (track direction) when detecting reflected light. More specifically, as shown in FIG. 3B, the photodetecting element 15 has four light receiving portions A to D. The light receiving portions A and D are arranged so as to be on the outer peripheral side of the disk with respect to the center G0 of the groove. On the other hand, the light receiving portions B and C are arranged so as to be on the inner peripheral side of the disk with respect to the groove center G0.

  The amplifiers 16A to 16D amplify the outputs of the light receiving units A to D of the light detection element 15 and output the amplified outputs to the addition circuits 17A to 17D, respectively. The adder circuit 17A adds the outputs of the amplifiers 16A and 16D and outputs the obtained tracking detection signal TKA, and the adder circuit 17B adds the outputs of the amplifiers 16B and 16C. A tracking detection signal TKB is output. That is, the reflected light from the region including the outer boundary S1 of the groove as shown in FIG. 3A is converted into the tracking detection signal TKA, and the reflected light from the region including the inner boundary S2 of the groove is converted to the reflected light. It is converted into a tracking detection signal TKB.

  The adder circuit 17C adds the outputs of the amplifiers 16A and 16C and outputs the obtained focus detection signal FCC. The adder circuit 17D adds the outputs of the amplifiers 16B and 16D to obtain The obtained focus detection signal FCD is output.

  The servo processing block 24 generates a focus control signal FCS based on the focus detection signals FCC and FCD, generates a tracking control signal TRK based on the tracking detection signals TKA and TKB, and outputs the generated signal to the optical pickup 10. . Thereby, the optical pickup 10 is controlled so that the laser beam is accurately focused and tracked on the optical disc 2. Note that such focus control and tracking control are realized by a known method.

  The incidental information extraction block 32 extracts incidental information recorded on the optical disc 2 based on the tracking detection signals TKA and TKB. The data detection block 34 reproduces data recorded on the optical disc 2 based on the tracking detection signals TKA and TKB and the focus detection signals FCC and FCD.

  FIG. 4 is a block diagram showing an example of the configuration of the incidental information extraction block 32 of FIG. The incidental information extraction block 32 includes an AGC 42A, 42B, a balance adjustment unit 44, a subtraction circuit 46, an LPF 48, a gain amplifier 52, an incidental information extractor 54, an incidental information detection determination unit 56, and an incidental information detection rate. And a measuring device 58. The balance adjustment unit 44 includes balance adjusters 44A and 44B.

  The AGCs 42A and 42B normalize the amplitudes of the tracking detection signals TKA and TKB, respectively, and output them to the balance adjusters 44A and 44B, respectively. The balance adjusters 44A and 44B adjust the amplitudes of the output signals of the AGCs 42A and 42B based on the balance adjustment signal BAL, respectively, and output them to the subtraction circuit 46 as tracking detection signals BTA and BTB after balance adjustment. For example, when the balance adjustment signal BAL increases, the balance adjuster 44A increases the amplitude of the output signal of the AGC 42A, and the balance adjuster 44B decreases the amplitude of the output signal of the AGC 42B. In other words, the balance adjusters 44A and 44B adjust the output signal of the AGC 42A and the output signal of the AGC 42B so that the ratio of the amplitudes of both is the ratio corresponding to the balance adjustment signal BAL.

  The subtraction circuit 46 obtains the difference between the tracking detection signals BTA and BTB after balance adjustment, and outputs the obtained differential signal to the LPF 48. The LPF 48 outputs the low frequency component of the differential signal output from the subtraction circuit 46 to the gain amplifier 52. The gain is set in the gain amplifier 52 according to the gain amplifier control signal AMC. The gain amplifier 52 amplifies the output of the LPF 48 according to the set gain and outputs the amplified output to the incidental information extractor 54. The incidental information extractor 54 extracts incidental information based on the output of the gain amplifier 52 and outputs the extracted incidental information to the incidental information detection determination unit 56.

  The incidental information detection determination unit 56 determines whether or not the incidental information is correctly obtained based on the timing at which the incidental information is obtained, and outputs the determination result to the incidental information detection rate measuring unit 58. The incidental information detection rate measuring unit 58 measures the rate at which the incidental information is obtained based on the determination result by the incidental information detection determining unit 56 and outputs the measurement result to the central control block 26 as the incidental information detection rate. The incidental information detection rate is a ratio of the amount of incidental information detected when reproduction or recording is performed with respect to a data area of a certain size to the amount of incidental information that can exist in the data area. The central control block 26 generates a balance adjustment signal BAL and outputs it to the balance adjusters 44A and 44B so that the incidental information can be accurately obtained.

  FIG. 5 is a graph showing the relationship between the balance adjustment signal BAL and the incidental information detection rate. The recording marks and spaces formed in the groove of the optical disc 2 appear as in-phase data signals in the tracking detection signals TKA and TKB. In the differential signal output from the subtracting circuit 46, the in-phase data signals included in the tracking detection signals TKA and TKB are canceled out, so that the influence on the extracted incidental information is small. However, when the amplitudes of the normalized signals output from the AGCs 42A and 42B are different, the in-phase data signals are not sufficiently canceled out and the incidental information detection rate is lowered.

  Since the balance adjusters 44A and 44B change the amplitude ratio between the output signal of the AGC 42A and the output signal of the AGC 42B according to the balance adjustment signal BAL, FIG. 5 shows the change in the incidental information detection rate according to the amplitude ratio. It can be said that it shows.

  The value and amplitude ratio of the balance adjustment signal BAL at which the incidental information detection rate becomes the highest are substantially the same when the recorded disc is reproduced and when the data is recorded. However, as shown in FIG. 5, at the time of recording, the change of the incidental information detection rate with respect to the change of the value of the balance adjustment signal BAL and the amplitude ratio is larger than at the time of reproduction.

  FIG. 6A is a graph showing the waveform of the differential signal output from the subtraction circuit 46 of FIG. 4 in an ideal case. FIG. 6B is a graph showing the waveform of the differential signal when the amplitude balance of the signals input to the subtracting circuit 46 in FIG. 4 is not appropriate.

  In the case of FIG. 6B, the magnitude of the data signal leaked into the differential signal is large, and the accompanying information may not be obtained. For this reason, it is desirable to reduce leakage of the data signal into the differential signal by appropriately adjusting the amplitude ratio of the output signals of the balance adjusters 44A and 44B. For example, the central control block 26 outputs the balance adjustment signal BAL so that the incidental information detection rate output from the incidental information detection rate measuring device 58 becomes the highest, whereby the amplitude of the output signal of the balance adjusters 44A and 44B. Set the ratio.

  As shown in FIG. 5, since the optimum value of the balance adjustment signal BAL is substantially the same at the time of reproducing the recorded disc and at the time of recording the data, it may be as follows. That is, the central control block 26 obtains the balance adjustment signal BAL so that the incidental information detection rate becomes the highest as described above during the reproduction of the recorded disc. In other words, balance adjustment is performed in which the amplitude ratio of the output signals of the balance adjusters 44A and 44B is set. Thereafter, at the time of data recording, the central control block 26 outputs the obtained balance adjustment signal BAL.

  As described above, according to the optical disk apparatus of FIG. 2, the groove wobble on the optical disk can be accurately detected during data recording, and the incidental information such as ADIP recorded by the wobble can be accurately detected. Can do.

  The central control block 26 outputs the balance adjustment signal BAL obtained at the time of reproducing the recorded disc in this way at the time of data recording, and based on the incidental information detection rate acquired at the time of data recording, at all times. Balance adjustment may be performed by obtaining an optimal balance adjustment signal BAL.

  As a result, without increasing the circuit scale, the incidental information detection rate can be maximized at all times during data recording, regardless of variations in laser power or optical disc.

(First modification)
FIG. 7 is a block diagram showing an example of the configuration of the incidental information extraction block 232 in the optical disc apparatus according to the first modification of the embodiment of the present invention. In this modified example, in the optical disc apparatus of FIG. 2, an incidental information extraction block 232 is used instead of the incidental information extraction block 32. The supplementary information extraction block 232 in FIG. 7 includes a balance adjustment unit 244 instead of the balance adjustment unit 44 in the supplementary information extraction block 32 in FIG. 4, and further includes an amplitude difference detector 262. The balance adjustment unit 244 includes balance adjusters 244A and 244B.

  During reproduction of a recorded disc, the balance adjustment is performed by adjusting the amplitude ratio of the output signals of the balance adjusters 244A and 244B in the same manner as described with reference to FIGS. Thereafter, during data recording, the amplitude difference detector 262 detects the difference in amplitude of the signals output from the AGCs 42A and 42B, and constantly reduces the amplitude difference based on the detected amplitude difference. The amplitude ratio of the output signals of the balance adjusters 244A and 244B is adjusted. The amplitude difference detector 262 includes, for example, a detector and an integrator.

  According to the incidental information extraction block 232 of FIG. 7, it is possible to maximize the incidental information detection rate at the time of data recording regardless of variations in laser power and optical disc.

(Second modification)
FIG. 8 is a block diagram showing an example of the configuration of the incidental information extraction block 332 in the optical disc apparatus according to the second modification of the embodiment of the present invention. In this modified example, in the optical disc apparatus of FIG. 2, an incidental information extraction block 332 is used instead of the incidental information extraction block 32. The incidental information extraction block 332 in FIG. 8 includes a balance adjustment unit 344 instead of the balance adjustment unit 44 in the incidental information extraction block 32 in FIG. 4, and further includes a phase difference detector 364. The balance adjustment unit 344 includes balance adjusters 344A and 344B.

  When reproducing the recorded disc, the amplitude ratio of the output signals of the balance adjusters 344A and 344B is adjusted in the same manner as described with reference to FIGS. Thereafter, at the time of data recording, the phase difference detector 364 detects the phase difference between the signals output from the AGC 42A and 42B, and constantly reduces the phase difference based on the detected phase difference. The amplitude ratio of the output signals of the balance adjusters 344A and 344B is adjusted.

  Here, the phase difference refers to a phase difference caused by a difference in frequency characteristics of the tracking detection signals TKA and TKB. The main factor is the output from the four light receiving portions A to D of the light detection element 15. There are variations in frequency characteristics of signals. Due to this phase difference, the data signal is not canceled out, and leakage into the differential signal output from the subtraction circuit 46 occurs. In particular, when data is recorded, the frequency characteristic variation of the output signal of the light detection element 15 becomes more remarkable.

  According to the incidental information extraction block 332 of FIG. 8, it is possible to always maximize the incidental information detection rate at the time of data recording regardless of the frequency characteristics of the output signal of the light detection element 15, laser power, or variations in the optical disk. .

  In the above embodiment, instead of performing the balance adjustment by obtaining the balance adjustment signal BAL during reproduction of the recorded disc, the balance adjustment signal BAL may be obtained during recording in the laser power learning area. That is, the central control block 26 records in a PCA (Power Caribration Area) area, which is a laser power learning area, and obtains a balance adjustment signal based on the incidental information detection rate at that time so as to increase the incidental information detection rate. . Thereafter, at the time of data recording, the central control block 26 outputs the obtained balance adjustment signal.

  The PCA area is an area prepared on the inner periphery of the optical disk for laser power adjustment. In addition to the PCA area, the outermost peripheral area of the optical disk may be used to perform test writing for balance adjustment.

  When the optimum balance adjustment signal BAL value is different between the outer circumference and the inner circumference, balance adjustment is performed so that the incidental information detection rate is maximized at each of the outer circumference and the inner circumference. The signals given to the balance adjusters 44A and 44B may be obtained by linear interpolation based on the cases of the outer circumference and the inner circumference.

  As described above, if the balance adjustment is performed before the start of data recording on the optical disc, it is not necessary to reproduce the recorded disc and perform the balance adjustment.

  Even in this case, the central control block 26 outputs the obtained balance adjustment signal BAL, and then always obtains the optimum balance adjustment signal BAL based on the incidental information detection rate acquired at the time of data recording. May be performed. Further, instead of the incidental information extraction block 32, an incidental information extraction block 232 or an incidental information extraction block 332 may be used.

  Further, in the above embodiment, instead of performing the balance adjustment by obtaining the balance adjustment signal BAL during reproduction of the recorded disc, the balance adjustment signal BAL is obtained during reproduction of the PCA area (laser power learning area) after laser power learning. You may do it. That is, the central control block 26 performs recording on the PCA area and learns the laser power, then reproduces the PCA area, and adjusts the balance so that the incidental information detection rate becomes higher based on the incidental information detection rate at that time. Find the signal. Thereafter, at the time of data recording, the central control block 26 outputs the obtained balance adjustment signal.

  Then, since balance adjustment can be performed without newly using a PCA area, it is not necessary to consider the shortage of the PCA area and the increase in the laser power learning time.

  Even in this case, the central control block 26 outputs the obtained balance adjustment signal BAL, and then always obtains the optimum balance adjustment signal BAL based on the incidental information detection rate acquired at the time of data recording. May be performed. Further, instead of the incidental information extraction block 32, an incidental information extraction block 232 or an incidental information extraction block 332 may be used.

  As described above, the present invention makes it possible to more accurately extract wobbles and accompanying information recorded by wobbles, so that it is useful for optical disk devices and the like that perform high-speed recording.

It is explanatory drawing which shows the example of the structure of the recording surface of an optical disk. 1 is a block diagram of an optical disc apparatus according to an embodiment of the present invention. (A) is a top view of the optical disk of FIG. FIG. 3B is a block diagram illustrating a configuration of the light detection unit 14 in FIG. 2. It is a block diagram which shows the example of a structure of the incidental information extraction block of FIG. It is a graph which shows the relationship between a balance adjustment signal and incidental information detection rate. (A) is a graph which shows the waveform of the differential signal output from the subtraction circuit of FIG. 4 in an ideal case. (B) is a graph which shows the waveform of a differential signal in case the balance of the amplitude of the signal input into the subtraction circuit of FIG. 4 is not appropriate. It is a block diagram which shows the example of a structure of the incidental information extraction block in the optical disk apparatus which concerns on the 1st modification of embodiment of this invention. It is a block diagram which shows the example of a structure of the incidental information extraction block in the optical disk apparatus which concerns on the 2nd modification of embodiment of this invention.

Explanation of symbols

10 Optical Pickup 11 Semiconductor Laser (Light Irradiation Element)
12 Semiconductor Laser Drive Block 14 Photodetector 22 Semiconductor Laser Control Block 24 Servo Processing Block 26 Central Control Block (Control Unit)
30 Reproduction signal processing block 32, 232, 332 Attached information extraction block 34 Data detection block 42A, 42B AGC
44, 244, 344 Balance adjustment unit 46 Subtraction circuit 48 LPF
52 Gain Amplifier 54 Attached Information Extractor 56 Attached Information Detection Determinator 58 Attached Information Detection Rate Measuring Unit 262 Amplitude Difference Detector 364 Phase Difference Detector

Claims (15)

An optical disk device for extracting auxiliary information recorded by wobble on a track on an optical disk,
A light irradiation element for irradiating the track with a light beam;
The first reflected light from the region including the boundary on the outer peripheral side of the track and the second reflected light from the region including the boundary on the inner peripheral side of the track are detected, and the first and second reflected light are detected. A photodetection unit that outputs first and second detection signals corresponding to each;
A first gain adjuster that normalizes and outputs the amplitude of the first detection signal;
A second gain adjuster that normalizes and outputs the amplitude of the second detection signal;
The output signals of the first and second gain adjusters are adjusted so that the ratio between the amplitudes of the first and second gain adjusters is a ratio corresponding to the balance adjustment signal. A balance adjustment unit that outputs the second detection signal;
A subtractor for obtaining and outputting a difference between the first detection signal after balance adjustment and the second detection signal after balance adjustment;
An auxiliary information extractor for obtaining the auxiliary information based on the output of the subtractor;
An optical disc apparatus comprising: a control unit that generates and outputs the balance adjustment signal so that the supplementary information is accurately obtained. The optical disc apparatus according to claim 1,
An optical disc apparatus, further comprising: an incidental information detection / determination unit that determines whether the incidental information is correctly obtained by the incidental information extractor and outputs the determination result. The optical disk apparatus according to claim 2, wherein
An optical disc apparatus, further comprising: an incidental information detection rate measuring device that measures a rate at which the incidental information is obtained based on the determination result and outputs the measurement result as an incidental information detection rate. The optical disk apparatus according to claim 3,
The controller is
An optical disc apparatus characterized in that, when a recorded disc is reproduced, the balance adjustment signal is obtained so that the incidental information detection rate is increased, and the obtained balance adjustment signal is output during data recording. The optical disk apparatus according to claim 4, wherein
The controller is
An optical disc apparatus characterized in that, after outputting the obtained balance adjustment signal, the balance adjustment signal is obtained and outputted so that the incidental information detection rate is increased during data recording. The optical disk apparatus according to claim 4, wherein
During data recording, an amplitude difference between the output of the first gain adjuster and the output of the second gain adjuster is detected, and the balance adjustment unit is controlled so that the difference in amplitude is reduced. An optical disc apparatus further comprising an amplitude difference detector. The optical disk apparatus according to claim 4, wherein
During data recording, a phase difference between the output of the first gain adjuster and the output of the second gain adjuster is detected, and the balance adjustment unit is controlled so that the phase difference is reduced. An optical disc apparatus further comprising a phase difference detector. The optical disk apparatus according to claim 3,
The controller is
An optical disc apparatus characterized by obtaining the balance adjustment signal so as to increase the incidental information detection rate during recording in a laser power learning area, and outputting the obtained balance adjustment signal during data recording. . The optical disc apparatus according to claim 8, wherein
The controller is
An optical disc apparatus characterized in that, after outputting the obtained balance adjustment signal, the balance adjustment signal is obtained and outputted so that the incidental information detection rate is increased during data recording. The optical disc apparatus according to claim 8, wherein
During data recording, an amplitude difference between the output of the first gain adjuster and the output of the second gain adjuster is detected, and the balance adjustment unit is controlled so that the difference in amplitude is reduced. An optical disc apparatus further comprising an amplitude difference detector. The optical disc apparatus according to claim 8, wherein
During data recording, a phase difference between the output of the first gain adjuster and the output of the second gain adjuster is detected, and the balance adjustment unit is controlled so that the phase difference is reduced. An optical disc apparatus further comprising a phase difference detector. The optical disk apparatus according to claim 3,
The controller is
The balance adjustment signal is obtained so that the incidental information detection rate is increased during reproduction of the laser power learning area after laser power learning, and the obtained balance adjustment signal is output during data recording. An optical disk device. The optical disk device according to claim 12, wherein
The controller is
An optical disc apparatus characterized in that, after outputting the obtained balance adjustment signal, the balance adjustment signal is obtained and outputted so that the incidental information detection rate is increased during data recording. The optical disk device according to claim 12, wherein
During data recording, an amplitude difference between the output of the first gain adjuster and the output of the second gain adjuster is detected, and the balance adjustment unit is controlled so that the difference in amplitude is reduced. An optical disc apparatus further comprising an amplitude difference detector. The optical disk device according to claim 12, wherein
During data recording, a phase difference between the output of the first gain adjuster and the output of the second gain adjuster is detected, and the balance adjustment unit is controlled so that the phase difference is reduced. An optical disc apparatus further comprising a phase difference detector.

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