JP2009009662A - Optical disk device and its control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical disk device capable of reading BCA data with higher reliability. <P>SOLUTION: The optical disk device is provided with a BCA playback part for reading BCA data recorded in the burst cutting area of an optical disk to output a BCA playback signal, a data detection part for generating BCA data from the BCA playback signal, and a rotational direction control unit for rotating the optical disk in a forward direction and a backward direction. The data detection part composes first BCA data obtained from the BCA playback signal when the optical disk is rotated in the forward direction and second BCA data obtained from the BCA playback signal when the optical disk is rotated in the backward direction to generate BCA data. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an optical disc apparatus and a control method thereof, and more particularly to an optical disc apparatus that reads BCA data recorded in a burst cutting area and a control method thereof.

  In a conventional DVD, an area called BCA (burst cutting area) is provided on the inner circumference side of an area where normal data is recorded, and BCA data is recorded in this area. The BCA data includes basic information necessary for reproducing a DVD. For this reason, in BCA, the bit length and the like are set sufficiently larger than those in a normal data recording area, so that reliable reproduction with few errors can be performed.

Patent Document 1 discloses one of BCA data reproduction technologies, and in particular, discloses a BCA data reproduction technology for an optical disc of the HD DVD standard.
JP 2007-35170 A

  In an HD DVD standard optical disc, copyright protection information called AACS (Advanced Access Content System) is recorded as BCA data. For this reason, in the HD DVD standard optical disc on which AACS is recorded, the reproduction of the optical disc itself cannot be performed unless the BCA data can be read, and it is very important to read the BCA data with high reliability.

  The technique disclosed in Patent Document 1 is one of the techniques for improving the reliability of reading BCA data on an optical disc of the HD DVD standard. However, considering the importance of reading BCA data, there is a strong demand for further improvement in reliability. It is where it is done.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide an optical disc apparatus capable of reading BCA data with higher reliability and a control method therefor.

  In order to solve the above problems, an optical disc apparatus according to the present invention reads a BCA data recorded in a burst cutting area of an optical disc and outputs a BCA reproduction signal as described in claim 1. And a data detection unit that generates the BCA data from the BCA reproduction signal, and a rotation direction control unit that rotates the optical disc in a direction opposite to the normal direction, and the data detection unit moves the optical disc in the forward direction. Generated by synthesizing the BCA data from the first BCA data obtained from the BCA reproduction signal when rotated and the second BCA data obtained from the BCA reproduction signal when the optical disk is rotated in the reverse direction. It is characterized by.

  In order to solve the above-mentioned problem, the control method of the optical disc apparatus according to the present invention includes (a) reading BCA data recorded in a burst cutting area of an optical disc, (B) generating the BCA data from the BCA playback signal, and (c) rotating the optical disc in the direction opposite to the normal direction. In step (b), the optical disc is The BCA data is synthesized from the first BCA data obtained from the BCA reproduction signal when rotated in the direction and the second BCA data obtained from the BCA reproduction signal when the optical disk is rotated in the reverse direction. It is characterized by generating.

  According to the optical disc apparatus and the control method thereof according to the present invention, BCA data can be read with higher reliability.

  Embodiments of an optical disc apparatus and a control method thereof according to the present invention will be described with reference to the accompanying drawings.

(1) First Embodiment FIG. 1 is a diagram showing a burst cutting area (hereinafter referred to as BCA) of an optical disc 100 reproduced by an optical disc apparatus 1 according to this embodiment. The BCA is an area provided on the inner peripheral side of the optical disc 100. BCA data is recorded by removing the recording layer in a stripe shape with a laser beam. In the HD DVD standard, the same BCA data is recorded in the A area and the B area to provide redundancy and improve reading reliability. A mirror area m, which is an unrecorded area, is provided between the A area and the B area. Data recorded in the A area is called A data, and data recorded in the B area is called B data.

  In the present embodiment, as indicated by arrows in FIG. 1, the optical disc 100 is rotated in the forward direction and the reverse direction, and the first BCA data and the second BCA data obtained from the respective rotation directions are acquired. This further increases the redundancy and further improves the reliability of reading the BCA data. This operation will be described later.

  FIG. 2 shows the structure of the A data and B data. The A data and the B data each have a preamble, information data, an error detection code (sometimes referred to as EDC), and an error correction code. In addition, nine kinds of synchronization codes of synchronization code 0 to synchronization code 5 and synchronization code 13 to synchronization code 15 are provided at the head of each row direction data. The information data itself is composed of 19 columns of 4 bytes of row data, and the data is 76 bytes in total.

  It is possible to detect the presence / absence of errors in the entire information data and the presence / absence and number of errors in columns by EDC and error correction code syndrome calculation. Further, if the number of errors is within a predetermined range, it is possible to correct the error by using an error correction code.

  Patent Document 1 discloses a technique for detecting the presence or absence of an error in each column of A data and B data, and obtaining error-free BCA data as the entire information data by combining columns without error. Also, a technique is disclosed in which when there is an error in both of the same column, the column with the least error is selected, the total number of errors is reduced, and then the error is corrected. In this way, by complementing or replacing the A data and the B data with each other, errors can be reduced to the extent that there is no error as a whole or error correction is possible.

  However, even if such processing is performed, an error that cannot be corrected may remain.

  In the optical disc apparatus 1 according to the first embodiment, in order to deal with such a case, the above complement or replacement process is performed on the first BCA data obtained by the forward rotation, and an error still remains. In this case, the optical disc 100 is rotated in the reverse direction to obtain the second BCA data, and the same processing as the complement or replacement processing performed on the A data and the B data is performed in the first and It is assumed that it is performed on the second BCA data.

  FIG. 3 is a diagram illustrating a waveform of a BCA reproduction signal obtained when the optical disc 100 is rotated in the forward direction and a reading flag indicating whether or not reading is possible. A black area in FIG. 3 represents a defect due to dirt or scratches attached to the BCA. When reading BCA data, a clock signal is extracted from the BCA reproduction signal, and the data is read in synchronization with the clock signal. For this reason, not only BCA data cannot be read in the defect area due to signal attenuation due to the defect, but also a predetermined period until synchronization is recovered even in the area behind the defect area (the area on the right side of the defect in FIG. 3) due to loss of synchronization due to the defect. BCA data cannot be read. Further, the BCA reproduction signal has a fluctuation in waveform due to fluctuations in gain and the like in the area after the defect area due to amplitude fluctuations in the defect area. This is also one of the causes that the area after the defect area cannot be read.

  On the other hand, FIG. 4 is a diagram illustrating a waveform of a BCA reproduction signal obtained when the optical disc 100 is rotated in the reverse direction and a reading flag indicating whether or not reading is possible. In this case, the front side of the defect area (the area on the left side of the defect in FIG. 4) becomes a period of synchronization recovery and cannot be read.

  As can be seen from a comparison between FIG. 3 and FIG. 4, the unreadable area before and after the defect area is reversed by the reversal of the rotation direction. This suggests that the reading rate can be improved by complementing or replacing the first BCA data obtained by forward rotation and the second BCA data obtained by backward rotation. ing.

  FIG. 5 is a block diagram illustrating a configuration example of the optical disc apparatus 1 according to the first embodiment.

  The BCA reproduction signal read from the optical disk 100 by the optical pickup 3 is adjusted in gain and offset by the preamplifier 4, converted into a digital signal by the AD converter 5, and becomes a digital amount of BCA reproduction signal. The optical pickup 3, the preamplifier 4, and the AD converter 5 constitute a BCA reproducing unit.

  The BCA reproduction signal is binarized by the BCA waveform shaping unit 6 and input to the BCA data detection unit 7. The BCA data detection unit 7 includes an A and B data processing unit 20, first and second BCA data processing units 21, a syndrome calculation unit 22, a data storage unit 23 composed of SRAM and flip-flops, an error correction unit 24, and the like. It is configured with. Each component block of the BCA data detection unit 7 performs BCA data detection processing (to be described later) while exchanging data with the memory 10 via the memory control unit 8 to generate BCA data with no errors or reduced errors. ing. The generated BCA data is output to the decoding unit 9 and decoded.

  On the other hand, the rotation direction control unit 12 controls the rotation direction of the optical disc 100 so as to be changeable between a forward direction and a reverse direction. The rotation direction control signal is sent to the servo control circuit 13, rotation servo control corresponding to the forward direction and the reverse direction is performed, and a drive signal is output to the spindle motor 2 via the spindle drive control circuit 14.

  The servo control circuit 13 also performs tracking servo control and focus servo control for the optical pickup 3, and these servo control signals are output to the optical pickup 3 via the focus / tracking drive control circuit 15.

  The BCA data detection process of the optical disc apparatus 1 configured as described above will be described. FIG. 6 is a flowchart showing an example of the BCA data detection process of the optical disc apparatus 1 according to the first embodiment.

  First, in step ST1, the optical disc 100 is rotated in the forward direction to acquire first BCA data, and then stored in the memory 10 (step ST2). Next, the stored data is read from the memory 10, and error detection / correction processing is performed (step ST3).

  The error detection / correction processing is processing for performing error detection processing on the A data and B data recorded on the optical disc 100, and complementing or replacing if there is an error. Also included is a process of correcting errors by combining columns with few errors. These processes are performed by the processing of each component block of the A and B data processing unit 20, the syndrome calculation unit 22, the error correction unit 24, and the data storage unit 23.

  After the error detection / correction process, it is determined in step ST4 whether or not an error remains in the first BCA data. If no error remains, the process ends.

  On the other hand, if an error still remains after the error detection / correction process, the process proceeds to step ST5 and subsequent steps.

  In step ST5, the optical disc 100 is rotated in the reverse direction. Then, the second BCA data obtained by the reverse rotation is stored in the memory 10. Since the second BCA data at this stage is arranged in the reverse order to the first BCA data, the arrangement is changed to align with the first BCA data (step ST7).

  Thereafter, the first BCA data and the second BCA data are compared, and the column data having no error are combined. Alternatively, BCA data is synthesized by complementing or replacing column data with few errors, and if an error remains in the synthesized BCA data, error correction processing is performed (step ST8). This method is the same as the process of step ST3, and is performed by the processing of each constituent block of the first and second BCA data processing unit 21, syndrome calculation unit 22, error correction unit 24, and data storage unit 23. .

  The BCA data detection process is completed by the process of step ST8, and the BCA data is output from the BCA data detection unit 7 to the decode 9.

  In the optical disc apparatus 1 according to the first embodiment, in addition to the complementing or replacement process with A data and B data, the first BCA data obtained by forward rotation and the second BCA data obtained by reverse rotation are used. However, complementation or replacement processing is performed, and BCA data with fewer errors can be obtained.

  Further, since the first BCA data and the second BCA data are different in the area that is adversely affected before and after the defect area as shown in FIGS. 3 and 4, the reading area can be made by mutual complementation or replacement processing. The error is further reduced as a result.

(2) Other Embodiments FIG. 7 is a block diagram showing a configuration example of an optical disc apparatus 1a according to the second embodiment. The difference from the optical disc apparatus 1 according to the first embodiment is that an average processing unit 30 and a signal position determination unit 31 are added.

  The signal position determination unit 31 performs processing for determining the start point and end point of the BCA reproduction signal. The average processing unit 30 averages the first BCA reproduction signal obtained when rotating in the forward direction and the second BCA reproduction signal obtained when rotating in the reverse direction, and outputs the result to the BCA waveform shaping unit 6.

  The first BCA reproduction signal and the second BCA reproduction signal are averaged by being matched in the time axis direction based on the respective start points and end points determined by the signal position determination unit 31.

  FIG. 8 is a flowchart showing an example of BCA data detection processing in the optical disc apparatus 1a according to the second embodiment.

  The processing from step ST11 to step ST14 is processing at the time of forward rotation, and is basically the same processing as in the first embodiment, and thus the description thereof is omitted. However, the data stored in the memory 10 in step ST12 is different in that, in addition to the binarized first BCA data, the first BCA reproduction signal before binarization is also stored.

  If it is determined in step ST14 that an error remains in the first BCA data, the process proceeds to step ST15, and the optical disc 100 is rotated in the reverse direction.

  Next, in step ST16, the second BCA reproduction signal before binarization is stored in the memory 10. Then, the first BCA reproduction signal during forward rotation stored in step ST12 and the second BCA reproduction signal during reverse rotation stored in step ST16 are read from the memory 10, and both are averaged ( Step ST17).

  Next, the averaged BCA reproduction signal is binarized and stored in the memory (step ST18). The binarization process is performed by the BCA waveform shaping unit 6.

  Finally, the binarized BCA data is read and error detection is performed. If an error is detected, error correction processing is performed and the process is terminated (step ST19).

  In the optical disc device 1a according to the second embodiment, the first and second BCA reproduction signals are averaged, and the adverse effect of the waveform received before and after the defect area is reduced. As a result, BCA data with few errors can be generated.

  FIG. 9 is a block diagram illustrating a configuration example of an optical disc device 1b according to the third embodiment. The difference from the optical disk device 1 a according to the second embodiment is that a defect detection / signal replacement unit 40 is provided instead of the average processing unit 30.

  The defect detection / signal replacement unit 40 detects the defect area from the BCA reproduction signal, and converts the signals in the areas before and after the defect area into the first BCA reproduction signal rotated in the forward direction and the second BCA reproduction signal rotated in the reverse direction. Perform the replacement with. The signal position determination unit 31 determines the start point and the end point of the first and first BCA reproduction signals, respectively, in order to ensure the replacement alignment.

  FIG. 10 is a flowchart showing an example of BCA data detection processing in the optical disc apparatus 1b according to the third embodiment.

  Since the processing from step ST21 to step ST26 is the same as that of the second embodiment, the description thereof is omitted.

  In step ST27, the first BCA reproduction signal during forward rotation and the second BCA reproduction signal during reverse rotation stored in the memory 10 are read, and the areas before and after the defect are replaced. Specifically, a predetermined range area before and after the defect area detected by the defect detection / signal replacement unit 40 is selected, and a predetermined range area after the defect area is selected. The signal in the second area is replaced with the signal in the second area in the second BCA reproduction signal. Or, conversely, for the second BCA reproduction signal, the signal in the area before the defect area and the signal in the area before the first BCA reproduction signal are replaced.

  As described above, in the first BCA reproduction signal obtained when rotating in the forward direction, the signal in the area behind the defect area is adversely affected by the defect, while in the reverse direction, the area behind this defect is Not affected. Therefore, a signal with a cleaner waveform can be generated by replacing a signal that is adversely affected by the defect with a signal that is not affected by the defect.

  The same applies to the area on the front side of the defect of the second BCA reproduction signal during reverse rotation.

  The BCA reproduction signal in which the influence of the defect is reduced by the above replacement processing is synthesized, and then binarization processing is performed and stored in the memory 10 (step ST28).

  Finally, binarized BCA data is read and error detection is performed. If an error is detected, error correction processing is performed and the process is terminated (step ST29).

  In the optical disc device 1b according to the third embodiment, the adverse effect of the waveform received before and after the defect area is reduced by replacing the area waveform before and after the defect. As a result, generation of BCA data with few errors can be expected.

  As described above, according to the optical disc apparatuses 1, 1a, 1b and the control method thereof according to the above embodiments, BCA data can be read with higher reliability.

  Note that the present invention is not limited to the above-described embodiments as they are, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, the constituent elements over different embodiments may be appropriately combined.

The figure which illustrates BCA of the optical disk which the optical disk device concerning embodiment of this invention makes object. The figure which shows the data structural example of BCA data. The figure which illustrates the BCA reproduction signal when the optical disk with the defect is rotated in the forward direction, and the reading flag at that time. The figure which illustrates the BCA reproduction signal when the optical disk with the defect is rotated in the reverse direction and the reading flag at that time. 1 is a block diagram illustrating a configuration example of an optical disc device according to a first embodiment. 5 is a flowchart showing an example of BCA data detection processing in the optical disc apparatus according to the first embodiment. FIG. 6 is a block diagram showing a configuration example of an optical disc device according to a second embodiment. 9 is a flowchart showing an example of BCA data detection processing in the optical disc apparatus according to the second embodiment. FIG. 6 is a block diagram showing a configuration example of an optical disc device according to a second embodiment. 9 is a flowchart showing an example of BCA data detection processing in the optical disc apparatus according to the second embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical disk apparatus 2 Spindle motor 6 BCA waveform shaping part 7 BCA data detection part (data detection part)
12 Rotation direction control unit 21 First and second BCA data processing unit 30 Average processing unit 40 Defect detection / signal replacement unit

Claims (10)

A BCA reproduction unit that reads BCA data recorded in a burst cutting area of the optical disc and outputs a BCA reproduction signal;
A data detector for generating BCA data from the BCA reproduction signal;
A rotation direction control unit for rotating the optical disc in the forward direction and the reverse direction;
With
The data detection unit
From the first BCA data obtained from the BCA reproduction signal when the optical disk is rotated in the forward direction and the second BCA data obtained from the BCA reproduction signal when the optical disk is rotated in the reverse direction, the BCA Synthesize and generate data,
An optical disc device characterized by the above. The data detection unit
The presence or absence of an error in each of the data string that constitutes the first BCA data and the data string that constitutes the second BCA data is detected, and there is no error in the first BCA data; The BCA data is generated by combining the BCA data without error in the BCA data of 2;
The optical disc apparatus according to claim 1, wherein: The data detection unit
The presence or absence of an error in each of the data string constituting the first BCA data and the data string constituting the second BCA data is detected, and the data string of the first BCA data and the second BCA data Are combined so that the error is minimized, and error correction is performed after the combining to generate the BCA data.
The optical disc apparatus according to claim 1, wherein: A BCA reproduction unit that reads BCA data recorded in a burst cutting area of the optical disc and outputs a BCA reproduction signal;
A data detector for generating BCA data from the BCA reproduction signal;
A rotation direction control unit for rotating the optical disc in the forward direction and the reverse direction;
With
The data detection unit
The BCA reproduction signal when the optical disk is rotated in the forward direction and the BCA reproduction signal when the optical disk is rotated in the reverse direction are averaged, and the BCA data is generated from the averaged BCA reproduction signal. ,
An optical disc device characterized by the above. A BCA reproduction unit that reads BCA data recorded in a burst cutting area of the optical disc and outputs a BCA reproduction signal;
A data detector for generating BCA data from the BCA reproduction signal;
A rotation direction control unit for rotating the optical disc in the forward direction and the reverse direction;
A defect detector for detecting a defect area of the burst cutting area;
With
The data detection unit
Of the BCA playback signal when the optical disk is rotated in the forward direction, the defect area obtained from the playback signal for a predetermined period after the defect area and the BCA playback signal when the optical disk is rotated in the reverse direction Replacing the reproduced signal of a predetermined period after and generating the BCA data from the replaced BCA reproduced signal,
An optical disc device characterized by the above. (A) Read BCA data recorded in the burst cutting area of the optical disc, and output a BCA playback signal;
(B) generating BCA data from the BCA reproduction signal;
(C) rotating the optical disc in the forward direction and the reverse direction;
With steps,
In step (b)
From the first BCA data obtained from the BCA reproduction signal when the optical disk is rotated in the forward direction and the second BCA data obtained from the BCA reproduction signal when the optical disk is rotated in the reverse direction, the BCA Synthesize and generate data,
A method of controlling an optical disk device, comprising: In step (b)
The presence or absence of an error in each of the data string that constitutes the first BCA data and the data string that constitutes the second BCA data is detected, and there is no error in the first BCA data; The BCA data is generated by combining the BCA data without error in the BCA data of 2;
The method of controlling an optical disk device according to claim 6. In step (b)
The presence or absence of an error in each of the data string constituting the first BCA data and the data string constituting the second BCA data is detected, and the data string of the first BCA data and the second BCA data Are combined so that the error is minimized, and error correction is performed after the combining to generate the BCA data.
The method of controlling an optical disk device according to claim 6. (A) Read BCA data recorded in the burst cutting area of the optical disc, and output a BCA playback signal;
(B) generating BCA data from the BCA reproduction signal;
(C) rotating the optical disc in the forward direction and the reverse direction;
With steps,
In step (b)
The BCA reproduction signal when the optical disk is rotated in the forward direction and the BCA reproduction signal when the optical disk is rotated in the reverse direction are averaged, and the BCA data is generated from the averaged BCA reproduction signal. ,
A method of controlling an optical disk device, comprising: (A) Read BCA data recorded in the burst cutting area of the optical disc, and output a BCA playback signal;
(B) generating BCA data from the BCA reproduction signal;
(C) rotating the optical disc in the forward direction and the reverse direction;
(D) detecting a defect area of the burst cutting area;
With steps,
In step (b)
Of the BCA playback signal when the optical disk is rotated in the forward direction, the defect area obtained from the playback signal for a predetermined period after the defect area and the BCA playback signal when the optical disk is rotated in the reverse direction Replacing the reproduced signal of a predetermined period after and generating the BCA data from the replaced BCA reproduced signal,
A method of controlling an optical disk device, comprising:

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