JPH09231699A - Optical disk and drive device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical disk capable of accurately performing sector management at the recording/reproducing time, capable of speedily performing seek operation with high accuracy, and moderate in redundancy. SOLUTION: A timing generator 63 is controlled by a synchronization detecting part 62 in obtaining rotational synchronization from rotationally synchronizing information based on a reproduced signal PPRF from an optical disk, and track address information is reproduced by a grey code detecting part 64. Error detection is performed by an error detecting part 66 whenever the track address information, the rotationally synchronizing information and error detecting information in an access code are supplied form a register part 65 as error detecting codes, and its detecting result is given to a control part 67. In accordance with the error detecting result by the error detecting part 66, the operation control for recording/reproducing the optical disk is performed by the control part 67.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sample servo type optical disc in which the entire track address is gray coded and recorded, and an optical disc drive device thereof.

[0002]

2. Description of the Related Art Optical discs known today are rotatably driven by a spindle motor at a constant linear velocity (CLV) or a constant angular velocity (CAV), and are recorded on a recording track spirally or concentrically provided on the disc. Data is to be recorded.

The so-called self-clock method and the external clock method are known as the clock synchronization methods at the time of recording and reproducing the data of such an optical disk.

In the external clock system, a segment consisting of a servo area in which a servo signal is recorded and a data area in which data is recorded is arranged in a track direction which is a recording / reproducing direction, and a clock signal is generated by a servo signal in the servo area. A sample servo method (discrete block method) for performing synchronization and tracking servo control is known.

In FIG. 9, the track of the sample servo type optical disk is composed of a plurality of sectors which are recording units of n data, and one sector is composed of m segments. In addition, the first segment (first segment) of the plurality of segments is
It is a header 104 in which address data and the like are recorded.

The header 104 has a servo area 102.
And a sector mark area 105 in which a sector mark indicating the beginning of a sector is recorded, and an address area 106 in which the track address, sector address and the like are recorded. The segments other than the header 104 are composed of a servo area 102 and a data area 107.

In the servo area 102, a clock pit 108 for synchronizing clocks, and a pair of wobbles deviated to the outer and inner circumferences with respect to the track center for obtaining a tracking error signal and the like. A synchronization pattern 110 composed of pits 109 and an access code 111 are recorded.

As the access code 111, the data of the lower 4 bits of the track address is recorded in two pits using a gray code. This access code is recorded in a 16-track cycle so that adjacent tracks satisfy the characteristics of the gray code in which only one pit position is different.

By thus gray-coding the access code 111 and recording the lower 4 bits of the track address, it is possible to obtain address data from the access code 111 for short distance access such as seek, and perform high-speed seek. be able to.

However, in such an optical disc, since only the lower 4-bit track address is recorded in the access code 111, the header in which the track address, the sector address, etc. are recorded in order to obtain accurate address data. Needed 104. Therefore, the recording capacity of the data is reduced because the header 104 has to be recorded.

Therefore, the applicant of the present application has filed Japanese Patent Application Laid-Open No.
As disclosed in Japanese Patent No. 929, an optical disc is proposed in which not only the lower part of the track address but all track addresses (including sector addresses) and sync patterns are recorded as access codes. In this optical disc, an access code including a track address and a synchronization pattern are sequentially recorded in the servo area.

That is, the track addresses are all 15
If it is a bit, each track address is a 3-bit least significant (LSB) word (0th bit to 2nd bit).
Bit), 4SB word (3rd to 5th bits),
It is divided into a total of 5 words, 3SB word (6th bit to 8th bit), 2SB word (9th bit to 11th bit), and most significant (MSB) word (12th bit to 14th bit). A word is recorded as the access code after being gray coded by pit position coding.

The access codes of these five words are distributed and recorded on the optical disc. For example, if one round of the optical disk is composed of 1024 segments, there are 1024 servo areas, and the LSB word of the access code is 1 in this servo area.
512 per cycle, 4 SB words 256 per cycle, 3 SB
128 words per cycle, 2 SB words 64 per cycle
32 MSB words are recorded in one round. That is, the above access code is recorded in a higher number in the lower word and a smaller number in the higher word. If you need more track addresses,
It is designed to allocate 16 more per lap. Also,
Of the remaining 32 access codes, 8 are recorded with unique codes for rotation synchronization, and the other 8 are recorded with information for specifying the segment number in which the unique code exists. The remaining 16 pieces are for recording other information.

In this recording medium, not only the lower part of the track address but also all track addresses are dispersed and recorded as the access code of each word as described above. Therefore, the track address is reproduced from the access code. Therefore, the recording of the header segment can be omitted and the data recording area can be increased.

Further, the applicant of the present application has filed Japanese Unexamined Patent Publication
Japanese Patent Publication No. 75 discloses an optical disc in which the entire track address is gray coded and recorded as the access code.

In this optical disc, by changing the coding rule of the lower word according to whether the upper word of the access code is odd or even,
The entire track address is gray coded.

That is, the value of the upper word of the access code is the original value (value before encoding). For this reason, when the upper word is an even number, the same value is taken, and when the upper word is an odd number, the complement is taken to be the conversion for the whole gray coding. The pit position coded according to the rule of 1 is recorded as an access code. The access code coded in the pit position is L
The SB word is recorded on the optical disc once every two segments, the 4SB word once every four segments, the 3SB word once every eight segments, and so on.

[0018]

By the way, in order to surely perform sector management based on the access code at the time of recording / reproducing, it is necessary to obtain accurate track address information from the access code in the optical disk drive device.

In the conventional optical disk, it takes a considerable amount of time to obtain accurate track address information in the optical disk drive device, and it takes a long time to start recording / reproducing and also a seek operation. There was a problem.

Therefore, an object of the present invention is to further accurately perform sector management at the time of recording / reproducing in the sample servo type optical disk as previously described by the applicant of the present invention. An object of the present invention is to provide an optical disk and an optical disk drive device for the optical disk, which are capable of high-speed seek, have high accuracy, and have little redundancy.

[0021]

An optical disk according to the present invention has a plurality of servo areas and a plurality of data areas that are repeatedly formed in each track, and has a track address that is entirely gray-coded by pit position encoding. As an access code that is divided into upper word and lower word and includes rotation synchronization information and error detection information depending on the pit position, the access code of the lower word is assigned to each servo area so that the frequency is higher than that of the upper word. It is characterized by being recorded in a dispersed manner.

In the optical disc according to the present invention, an access code including error detection information for address information is recorded in each servo area.

Further, in the optical disc according to the present invention, an access code including error detection information for address information and rotation synchronization information is recorded in each servo area.

Further, the optical disk drive device according to the present invention has a plurality of servo areas and a plurality of data areas which are repeatedly formed in each track, and the track address information, which is entirely gray-coded by pit position encoding, has a higher rank. As an access code that is divided into words and lower words and includes rotation synchronization information and error detection information depending on the pit position, it is distributed to each servo area so that the frequency of the access code of the lower word is higher than the frequency of the access code of the upper word. A drive unit for an optical disc that is recorded by performing a sector management based on the track code information included in the access code reproduced by the reproduction unit and the reproduction unit that reproduces the access code from the servo area. Access control means to access A timing control means for controlling the timing of the signal processing system based on the rotation synchronization information contained in the access code reproduced by the reproducing means, and based on the error detection information contained in the access code reproduced by the reproducing means. An error detecting means for detecting an error in the access code is provided, and when the error detecting means detects an error in the access code, the access control means prohibits access to the optical disk.

[0025]

Embodiments of the present invention will be described below with reference to the drawings.

The optical disk 10 according to the present invention is an optical disk of the sample servo system, and for example, as shown in FIG. 1, is composed of a plurality of sectors 1 which are recording units of n data, and one sector is It is composed of m segments. The first segment of the plurality of segments, that is, the first segment is a header 4 in which address data and the like are recorded.

The header 4 comprises a servo area 2, a sector mark area 5 in which a sector mark indicating the beginning of the sector 1 is recorded, and an address area 6 in which the track address, sector address, etc. are recorded. There is. The segments other than the header 4 are composed of a servo area 2 and a data area 3.

In the servo area 2, as shown in FIG. 2, an access code 21 that gives track address and rotation synchronization information and a servo pit 22 that gives tracking information are sequentially recorded.

Assuming that the track addresses are all 15 bits, the track addresses are 3 bits least significant (LSB) word (0th bit to 2nd bit) and 4SB words (3rd bit to 5th bit), respectively. Bit), 3
The SB word (6th to 8th bits), the 2SB word (9th to 11th bits), and the most significant (MSB) word (12th to 14th bits) are divided into a total of 5 words. With the word as the access code 21, by pit position coding as shown in FIG.
It is recorded in gray code.

Access code 21 of these five words
Are recorded dispersedly on the optical disc as shown in FIG. In FIG. 4, a plurality of straight lines shown in the radial direction of the optical disc indicate the servo areas 2, and the data areas 3 are between the servo areas 2. For example, if one round of the optical disc is composed of 1024 segments, the servo area 2 is also 1
In the servo area 2, 512 LSB words of the above access code 21, 512 4SB words per cycle, and 3SB words 128 per cycle exist in this servo area 2.
, 2 SB words are recorded in one round, 64 MSB words are recorded in 32 rounds, and so on. In other words, the access code 121 is recorded in a higher number in the lower word and a smaller number in the higher word. If more track addresses are needed, 16 more tracks may be allocated for each round.

In this example, since there are 5 words from LSB to MSB, the track address has 15 bits as information.

Of the remaining 32 access codes, 8 are unique codes for rotation synchronization and 8 are recorded with rotation synchronization information in which the unique code exists. The remaining 16 pieces are for recording error correction information and other information.

In the optical disc 10 having such a structure, not only the lower part of the track address but also all track addresses are dispersed and recorded as the access code 21 of each word as described above. It is possible to reproduce the track address from, and to omit the recording of the header segment to enlarge the data recording area.

Further, in the optical disc 10, the entire track address is gray coded by changing the coding rule of the lower word depending on whether the upper word of the access code is odd or even. That is, the value of the upper word of the access code is the original value (value before encoding). Therefore, when the upper word is an even number, the same value is taken, and when the upper word is an odd number, the complement (7's complement in FIG. 3, for example, 0 → 7, 1 → 6, etc.) is taken (first step). Processing), the conversion is performed for the entire gray coding, and the converted code is pit position coded by the rule shown in FIG. 3 and recorded as the access code (second step). processing).

As shown in FIG. 4, the pit position-coded access code has an LSB word once every two segments, a 4SB word once every four segments, and a 3SB word once every eight segments. Is recorded on the optical disc as follows. Although the access code is actually recorded in the embossed pits by the pit position coding (processing of the second step), the access code after the processing of the first step is shown in FIG. It is shown with a gray coded access code.

The pit pattern of each word of the access code is as shown in FIG. However, the access code (octal) shown in FIG. 5 does not indicate the actual arrangement on the disk, but indicates each word after the processing of the first stage. Note that the five-digit number in the upper right of FIG. 5 indicates the track address before the processing in the first stage, and each digit of this five-digit number is the value of each word of the access code.

Here, the track address is naturally different for each track, and moreover, it is necessary to emboss record with a gray code depending on the pit position so that the track address can be reproduced during high-speed seek. On the other hand, the unique code for rotation synchronization, that is, the rotation position information does not have to be a gray code because it is the same in the radial direction, but it does not need to be a gray code at the initial start-up, and even during seeking, rotation synchronization Therefore, it is necessary to emboss record with information based on the pit position so that Further, since tracking is applied at the time of recording / reproducing, it is sufficient that the error detection information for sector management at the time of recording / reproducing can be reproduced while the tracking is applied. Therefore, for example, if the recording method in the ROM disk in which the data in the data area is read-only is possible with NRZ or NRZI, the error detection information for sector management can also use NRZ or NRZI.

The access code can be used 16 times in one round in addition to the track address and the rotation synchronization information, and the error detection information for sector management is NRZ or NR.
When ZI is entered, one access code contains 8 bits of information. Therefore, if all the remaining access codes are used as error detection information and one error detection information is composed of 8 bits, error detection can be performed 16 times in one round.

When it is desired to increase the probability of one-time detection, the error detection information may be configured with 16 bits of two access codes. In this case, error detection can be performed eight times in one round.

The error detection information is added to the radius information, that is, the track address and the rotation synchronization information.

For example, when a CRC is used for error detection, for example, as shown in FIG. 6A, track address information and rotation synchronization information bits (that is, a relative position including CRCC, for example, 8 times / round CRCC). Check code = CRC for values 0 to 7)
Let C be the error detection information.

In the sample servo type optical disk drive device, the rotation synchronization is generally protected and the rotation synchronization cannot be lost. Therefore, it is not necessary to perform error detection on the rotation synchronization information. Therefore, the error detection information may correspond only to the radius information, that is, the track address, as shown in FIG.

The error detection information does not always have to correspond to the actually recorded access code. For example, as described above, 15 bits of track address information and 8 pieces of rotation synchronization information, that is, 3 bits are actually recorded in the access code, but error detection information for sector management at the time of recording / reproducing is recorded in 8-bit units. In such a case, error detection can be performed 16 times in one round. At this time, the rotation synchronization information to which the error detection information is added is not the actually recorded value of 3 bits but the information 4 indicating the position of 16 times.
Use bits. That is, as shown in FIG. 6C, track address information 15 bits and rotation synchronization information 4
An 8-bit CRCC for each bit is used as error detection information.

Here, in the case of CRC, error detection information CRC
The generation of C is represented by G (x) · Q (x) = xe + k · M (x) + R (x) in polynomial expression.

G (x) is a predetermined generator polynomial, M (x) is an information polynomial given by track address information (+ rotation synchronization information), and R (x) is error detection information. It is a remainder polynomial.

The optical disk 10 having such a structure is driven by an optical disk drive device 50 having a servo system having a structure as shown in FIG. 7, for example.

In this optical disk drive device 50, the optical disk 10 is rotated by a spindle motor 51 at a constant angular velocity (CAV), for example, and an optical head 53 is moved by a sled motor 52 in the disk radial direction. It is for optically scanning a track to record / reproduce data, and a signal processing unit 55 to which a detection signal from the optical head 52 is supplied via a matrix circuit 54 allows the spindle motor 51 and the thread to be slid. The drive control of the motor 52 is performed, and the focus servo and the tracking servo are applied to the optical head 53.

The optical head 53 is adapted to irradiate the optical disc 10 with a laser beam emitted by a laser diode (not shown) and receive return light by a split detector (not shown). Then, the matrix circuit 54 generates a focus error signal FE and a prepit reproduction signal PPRF by a predetermined calculation from each detection signal from the split detector of the optical head 53. The signal processing unit 55 also drives the drive circuits 55 and 56 based on the focus error signal FE and the prepit reproduction signal PPRF.
Thus, the optical head 53 is driven to apply focus servo and tracking servo.

In the optical disk drive device 50, the signal processing section 54 has the drive circuit 5 at the time of start-up.
The spindle motor 51 is driven by 8 to rotate the optical disk 10 by VAC, the rough focus servo is applied by the focus error signal FE, and the PLL is pulled in by the prepit reproduction signal PPRF to synchronize the rotation. Apply focus servo and tracking servo. The signal processing unit 54
Then, when the rotation synchronization is applied, the track address information can be obtained.

When recording / reproducing is actually performed, the drive circuit 59 drives the sled motor 52 to seek the optical head 52 to the target track, and the tracking servo is applied to the target track.

Here, the tracking servo is applied to the target track to complete the preparation for recording / reproducing. However, in consideration of the possibility that the access code of the address information of the target track is defective, this optical disk is considered. In the drive device 50, the signal processing unit 54 detects an error in an address to perform accurate sector management.

That is, the track address = radius information is reproduced when landing on the target track,
Further, since the rotation synchronization is obtained, the rotation synchronization information is also known. Therefore, the error detection information can be reproduced from the corresponding access code, and the error detection of the radius information and the rotation synchronization information can be performed based on the error detection information, and the recording / reproduction can be performed when there is no error. If there is an error, recording / reproduction can be prohibited.

The signal processing section 54 has a prepit reproduction signal PPRF as shown in FIG.
Is supplied via the input processing unit 61.
Gray code detecting section 64 and register section 65, timing generator 63 controlled by the synchronization detecting section 62, error detecting section 66 to which the output signal of the register section 65 is supplied, and detection result of the error detecting section 66. Is provided with a control unit 67 and the like.

In the input processing section 61, the reproduction signal PPRF of the prepit is A / D converted, and further binarized by digital processing.

Then, the synchronization detecting section 62 obtains the rotation synchronization from the rotation synchronization information in the access code based on the reproduction signal PPRF binarized by the input processing section 61, and controls the timing generator 63. To do.

The timing generator 63 generates timing information within one track. Then, the timing generator 63 outputs various timing information to the register unit 65, the error detection unit 66, and the control unit 67.
Give to.

In the gray code detecting section 64,
The reproduced signal PPR binarized by the input processing unit 61.
The radius information in the access code = track address is reproduced from F. Then, the Gray code detection unit 64 gives the radius information to the register unit 65 and the control unit 67.

Further, the register section 65 is a shift register which operates according to the timing information given by the timing generator 63, and is loaded with the radius information and the rotation synchronization information, and the error detection information in the access code is stored. When reproduced, this series of information is supplied to the error detection unit 66 as an error detection code.

Each time the error detection code is supplied from the register section 65, the error detection section 66 performs error detection on the error detection code and controls the detection result indicating the presence or absence of radius information or rotation synchronization information. It is supplied to the section 67.

When the control section 67 determines that there is no error in the radius information and the rotation synchronization information based on the result of the error detection by the error detection section 66, recording / reproducing is enabled. If it is determined that the radius information or the rotation synchronization information has an error, control for prohibiting recording / reproduction is performed. When the recording / playback is prohibited, the access code newly containing the distributed track address information is reached, the information is updated, the next error detection information is played back, the error detection operation is performed, and the access is performed. When it is determined that there is no error in the code, the recording / playback is enabled.

As described above, in the optical disc drive device 50, accurate signal management is performed by controlling the error detection of the access code in the signal processing unit 54 and controlling the recording / reproducing enabled state. You can

Here, in the control unit 67, if it is determined that the access code has an error as a result of the error detection by the error detection unit 66, the recording / reproducing is disabled immediately, and the error rate of the access code is high. Since it is easy to make it disable and the sector usage efficiency will decrease, if you do not disable it even if you judge that there is an error in the access code unless a servo error such as tracking occurs, the error rate of the access code will be. It is possible to prevent a decrease in sector usage efficiency when the value is high. This method can be adopted when the error detection probability based on the error detection information is high and the servo error signal is reliable.

Further, when the control section 67 determines that the access code has an error for a predetermined number of times as a result of the error detection by the error detection section 66, the recording / reproducing may be disabled. Good. Furthermore, when the error detection probability based on the error detection information is low, the number of times of protection is set even when recording / reproduction is enabled, and when it is determined that the access code has no error for a predetermined number of consecutive times. The recording / playback may be enabled.

Furthermore, when the error detection information is added only to the radius information, if it is determined that the radius information has an error, the access code newly containing the distributed track address information is reached. At the time when the information is updated, if the track is not updated, an error detection operation is immediately performed to enable recording / reproduction when it is determined that there is no error in the access code. Good. Further, even if the track is updated, if the error detection operation is performed on the one obtained by subtracting -1 from the reproduced address, the error detection operation can be performed immediately without obtaining the next error detection information.

[0065]

The optical disc according to the present invention is used as an access code in which a track address, which is entirely gray-coded by pit position encoding, is divided into an upper word and a lower word and includes rotation synchronization information and error detection information depending on the pit position. , The access code of the lower word is distributed and recorded in each servo area so that the frequency of the access code of the upper word is higher than the frequency of the access code of the upper word. Therefore, the reliability of the access code can be improved by the error detection information. . As a result, in the sample servo type optical disk, it is possible to provide an optical disk that can accurately perform sector management at the time of recording / reproducing, can perform high-speed seek, obtain the accuracy thereof, and have little redundancy. it can.

Further, in the optical disk drive apparatus according to the present invention, which is an optical disk drive apparatus, the access control means prohibits access to the optical disk when the error detection means detects an error in the access code.
The track address information, which has a plurality of servo areas and a plurality of data areas that are repeatedly formed on each track and is entirely gray-coded by pit position encoding, is divided into upper words and lower words, and rotation synchronization information according to pit positions. Sectors at the time of recording / reproducing to / from an optical disc in which the access code of the lower word is distributed and recorded in each servo area so that the frequency of the access code of the lower word is higher than that of the access code of the upper word. Can manage accurately.

[Brief description of drawings]

FIG. 1 is a diagram showing a recording format of an optical disc according to the present invention.

FIG. 2 is a diagram showing an access code and a servo pattern recorded in a servo area of an optical disc.

FIG. 3 is a diagram for explaining pit position coding for gray-coding the access code of the optical disc.

FIG. 4 is a diagram showing access codes (distributed address format) distributed on MSB words to LSB words and recorded on a disc.

FIG. 5 is an M of an access code recorded on an optical disc.
It is a figure which shows the pit pattern of SB word-LSB word.

FIG. 6 is a diagram showing various configurations of an access code to which error detection information is added.

FIG. 7 is a block diagram showing a basic configuration of an optical disc drive device for driving the optical disc.

FIG. 8 is a block diagram showing a main configuration of the optical disc drive device.

FIG. 9 is a diagram showing a recording format of a conventional optical disc in which a track address is gray coded and recorded.

[Explanation of symbols]

1 sector, 2 servo areas, 3 data areas, 10 optical disks, 21 access codes,
22 servo pits, 51 spindle motors, 5
2 thread motor, 53 optical head, 54 matrix circuit, 55 signal processing unit, 61 input processing unit, 62 synchronization detection unit, 63 timing generator, 64 Gray code detection unit, 65 register unit, 66 error detection unit, 67 control unit

Claims (4)

[Claims] 1. A track address, which has a plurality of servo areas and a plurality of data areas repeatedly formed on each track and is gray-coded as a whole by pit position encoding, is divided into an upper word and a lower word to form a pit position. An optical disc in which the access code including the rotation synchronization information and the error detection information is distributed and recorded in each servo area so that the frequency of the access code of the lower word is higher than that of the access code of the upper word. 2. The optical disc according to claim 1, wherein an access code including error detection information for address information is recorded in each servo area. 3. The optical disc according to claim 1, wherein an access code including error detection information for address information and rotation synchronization information is recorded in each servo area. 4. The track address information, which has a plurality of servo areas and a plurality of data areas repeatedly formed in each track and is entirely gray-coded by pit position encoding, is divided into an upper word and a lower word to form a pit. An optical disc drive in which the access code including rotation synchronization information and error detection information depending on the position is distributed and recorded in each servo area so that the frequency of the access code of the lower word is higher than that of the access code of the upper word. In the device, reproducing means for reproducing an access code from a servo area, and sector management based on track address information included in the access code reproduced by the reproducing means,
Access control means for accessing the optical disc; timing control means for controlling the timing of the signal processing system based on the rotation synchronization information contained in the access code reproduced by the reproducing means; and access code reproduced by the reproducing means. Error detecting means for detecting an error in the access code based on the included error detecting information, and when the error detecting means detects an error in the access code, the access control means prohibits access to the optical disc. Optical disk drive device.