JPH11175979A - Clock generating device, clock generating method and optical disk - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain fast and constant synchromization even when dust is stuck to an optical disk by forming embossed pits of a groove header even in address areas for every sector and generating a clock based on a detected wobbling signal. SOLUTION: The embossed pit string of a groove header GRH is formed in the address area ARI of an optical disk with the same cycle and the same phase as those of the wobbling of a groove GR. When a laser beam is irradiated, for example, on the position A of the groove of a user area AR2, synchronization information are obtained and, moerover, even when the beam is moved to the position B of the address area AR1, the same wobbling signal is obtained from the groove header GRH. Consequently, even when dust is stuck to the optical disk, detection pulses having a fast and constant cycle are obtained based on the wobbling signal obtained from the address areas to generate a correct clock and synchronization of respective circuits can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a clock generator for generating a synchronization signal from an optical disk, and the like.

[0002]

2. Description of the Related Art As a method of forming an address on an optical disk, it is known to form pits in advance by embossing when manufacturing an optical disk.

[0003] In an optical disk, for example, a sector is divided into sectors for every 2048 bytes of user data as a unit of recording and reproduction, and a sector address as a header is formed at the head of the sector.

The recording / reproducing apparatus for the optical disk reads the sector address, confirms that the address is a desired sector address, and then records / reproduces data in a recording / reproducing area following the header.

[0005]

By the way, today,
An optical disk having a very thin cover has been proposed. For example, if the cover of the optical disc has a thickness of 0.1 t
(= 0.1 [mm]), dust attached to the surface of the optical disk often causes some influence.

For example, data recorded in the user area may cause an error due to the attachment of dust. However, by increasing the redundancy to enhance the error correction capability, the occurrence of the error can be avoided.

On the other hand, in the address area, the area itself is small, and if the error correction capability is increased, the redundancy becomes redundant. Therefore, the error correction capability cannot be enhanced. Therefore, if the address area is covered by dust or the like, it becomes difficult to achieve synchronization. In particular, when synchronization is performed, there is a problem that it takes a long time to achieve synchronization.

The present invention has been proposed in view of such circumstances, and a clock generation device, a clock generation method, and an optical disk capable of achieving high-speed and stable synchronization even when dust adheres to the optical disk. The purpose is to provide.

[0009]

In order to solve the above-mentioned problems, in a clock generation apparatus according to the present invention, an address area and a user area are assigned to each sector, and a groove is formed in a meandering manner in the user area. At the same time, the land is also meandering, and in the address area, the embossed pits of the groove header are formed on the extension of the groove and meander with the same period and the same phase as the groove meandering. For optical discs,
An optical head that irradiates a laser beam and detects a reflected light thereof; a wobbling signal detecting unit that detects a wobbling signal corresponding to the meandering shape of the groove and the embossed pit of the groove header based on a detection output of the optical head; Clock generating means for generating a clock based on the wobbling signal having a predetermined period.

The clock generation device detects a wobbling signal corresponding to the meandering shape of the groove and the embossed pit of the groove header based on the detection output of the optical head, and generates a clock based on the detected wobbling signal having a constant period. Generate.

In the clock generation method according to the present invention, an address area and a user area are assigned to each sector,
In the user area, the groove is formed meandering, and the land is also formed correspondingly meandering.In the address area, the embossed pits of the groove header are on the extension of the groove and have the same period as the groove meandering. A laser beam is irradiated to an optical disk formed meandering in phase to detect reflected light,
A wobbling signal corresponding to the meandering shape of the groove and the embossed pit of the groove header is detected based on the detection output of the reflected light, and a clock is generated based on the detected wobbling signal having a constant period.

The clock generating method detects a wobbling signal corresponding to the meandering shape of the groove and the embossed pit of the groove header on the basis of the detection output of the optical head, and generates a clock based on the detected wobbling signal of a fixed period. Generate.

In the optical disc according to the present invention, a plurality of sectors are formed by dividing a data recording surface into radial areas, and each sector is assigned to an address area and a user area, and a groove is formed in a meandering manner in the user area. At the same time, the land is meandering accordingly,
In the address area, the embossed pits of the groove header are formed on the extension of the groove and meandering in the same cycle and in the same phase as the groove meandering.

[0014]

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

The optical disk according to the present invention can be applied to, for example, the optical disk 1 having the configuration shown in FIG.

In the optical disc 1, a data recording surface is divided into radial areas to form a sector structure, and the data recording surface is divided into concentric circles to form a plurality of zones Z0.
To Zn.

An address area AR1 to which an address is written is allocated at the head of each sector, and a user area A to which normal data is written is allocated to the remaining area.
R2 is assigned. In the user area AR2, the groove GR is formed to meander (wobble) so that synchronization information can be obtained. In the user area 2, the land is also formed by wobbling correspondingly. Therefore, the groove GR and the land are configured to be adjacent to each other in the radial direction of the optical disc 1.

In the track in the innermost zone Z0, the groove GR is formed so as to meander over a predetermined cycle, and the number of meanders of the groove GR is sequentially increased as moving to the outer zone. . This groove GR is a so-called zone CAV (Constant Liner Vel.)
ocity). Address area AR1
Are discretely arranged on an optical disk, and address information in sector units is recorded. In the address area AR1, a length corresponding to a certain period of the groove GR is assigned.

Here, in the optical disk of the groove recording system, in the address area AR1, as shown in FIG. 2, an embossed pit row of the groove header GRH is formed on the track center by the groove GR. The emboss pit row of the groove header GRH is the groove GR.
Are formed by wobbling with the same period and the same phase as the wobbling.

Thus, synchronization information (wobbling signal) is obtained when the laser beam irradiates a groove (for example, position A) in the user area AR2, and the irradiation position is changed from the user area AR2 to the address area AR.
Even when it changes to 1 (for example, position B), the same wobbling signal can be obtained from the groove header GRH.

In the land / groove recording type optical disk, as shown in FIG. 3, a groove header GRH is formed in the first half of the address area AR1, and a land header LH is formed in the second half. Groove header G
The pit row of RH is formed by wobbling on the extension of the groove GR and at the same period and the same phase as the wobbling, similarly to the above-described groove recording method. On the other hand, the pit row of the land header LH is on an extension of the wobbling land described above. The pit row of the land header LH has the same period as the wobbling of the groove GR, but is wobbled with the phase inverted. Here, land header L
The reason why the phase of the H pit train is inverted is that the groove G
This is because the phase of the wobbling signal obtained from the reflected light of R and the phase of the wobbling signal obtained from the reflected light of the land are different from each other by π.

Thus, similarly to the case of the groove recording method, the laser beam is applied to the groove G of the user area AR2.
A wobbling signal is obtained when irradiating R (for example, position C), and the irradiating position is set to the user area AR.
Even when the address changes from 2 to the address area AR1 (for example, position D), the same wobbling signal can be obtained from the groove header GRH. Further, even when the irradiation position of the laser beam moves between the pit rows of the land header LH (for example, position E) after passing through the pit row of the groove header GRH, the same wobbling signal is obtained. The optical disk 1 is manufactured by exposing the master disk to light by a mastering device 10 having the configuration shown in FIG. 4, for example.

The mastering device 10 combines a signal from the wobble signal generation circuit 11 and an address signal generation circuit 12 and outputs a drive signal SD;
A drive circuit 14 for driving the optical head 15 based on the drive signal SD, a spindle motor 17 for driving the master disk 16 to rotate, and a system control circuit (not shown) are provided.

The wobble signal generation circuit 11 outputs a sine wave signal of a predetermined frequency synchronized with the rotation of the master disc 16 as a wobble signal WB. Further, the wobble signal generation circuit 11 responds to the zoning by
The frequency of B is increased stepwise and output. Thereby, the wobble signal generation circuit 11 displaces the laser beam irradiation position by the wobble signal WB, and makes the groove GR meander over a predetermined period per sector.

The address signal generation circuit 12 generates an address signal SA whose value sequentially changes according to the displacement of the optical head 15 under the control of a system control circuit (not shown).

More specifically, the address signal generation circuit 12
Receives a timing signal such as an FG signal synchronized with the rotation of the disk master 16 from the spindle motor 17 or the like, counts the timing signal by a predetermined counter, and outputs address data I indicating the laser beam irradiation position.
Generate D. At this time, the address signal generation circuit 12
Indicates a sector mark SM, a synchronization timing data VFO, an address mark AM,
A postamble PA is added to generate a groove header GRH and a land header LH as required for the first half and the second half of the address area AR1, respectively. At this time, the groove header GRH is
The wobbling is performed in the same cycle and the same phase as the wobbling of R, and the land header LH is wobbled so that the phase thereof is inverted. Note that, as the synchronization timing data VFO, the same clock pattern as the clock pattern recorded / reproduced as the synchronization timing data VFO at the head of the user area AR2 is generated. The address signal generation circuit 12 converts the sector header thus generated into a serial data string, and modulates the serial data string in a predetermined format.

Then, the address signal generating circuit 12 supplies the modulated output to the synthesizing circuit 13 as an address signal SA. The address signal generation circuit 12 outputs the address signal SA at a timing corresponding to the scanning of the laser beam L.

The drive circuit 14 switches the driving conditions of the optical head 15 in accordance with the laser beam irradiation position at the timing synchronized with the rotation of the disk master 16, thereby zoning the disk master 16. Specifically, the drive circuit 14 divides the information recording surface of the disk master 16 into radial regions to form a sector structure,
The driving conditions of the optical head 15 are switched. Further, by changing the switching timing stepwise from the inner circumference to the outer circumference, the information recording surface is divided into concentric circles to form a plurality of zones Z0 to Zn.

The drive circuit 14 operates in the user area AR2 in accordance with the control of the system control circuit.
The laser beam irradiation position is displaced by the drive signal SD,
Thus, the groove GR is formed to meander in the user area AR2.

In the address area AR1, the displacement of the irradiation position of the laser beam is stopped in the first half of the address area AR1, and the light amount of the laser beam is intermittently started by the drive signal SD. A pit row is formed on the top. In the latter half of the address area AR1, the laser beam irradiation position is displaced to the track center by the inner land, and the light amount of the laser beam is intermittently raised by the drive signal SD, whereby the pit row is formed on the track center by the land. To form

At this time, the drive circuit 14 records the address data of the sector by the following groove GR on the track center in the first half of the address area AR1 in a pit row, and continues the second half of the address area AR1. The address data of the sector by the land on the inner peripheral side is recorded on the track center by a pit row.

The optical head 15 is configured such that the optical system is movable in the radial direction of the master disk 16. Further, when the optical head 15 prepares an optical disk from the disk master 16, the laser beam L is adjusted so that the width of the land formed between the groove GR formed by exposure to the laser beam L and the adjacent groove GR becomes substantially equal. Is set. Here, the spot shape of the laser beam L is set so that the effective exposure range by the laser beam L is expanded with respect to the width of the groove GR as the final target.
The light quantity is set. Therefore, the optical head 15 exposes the disk master 16 so that the optical disk created by the disk master 16 can be recorded between the land / groove GR.

The master disk 16 is formed, for example, by applying a resist to the surface of a glass substrate. Master disc 16
Is driven to rotate at a constant angular velocity by a spindle motor 17. Then, the optical head 15 irradiates the laser beam L onto the disk master 16 while being sequentially displaced from the inner circumference side to the outer circumference side of the disk master 16 by a predetermined thread mechanism in synchronization with the rotation of the disk master 16. . Thus, the optical head 15 forms a spiral track from the inner circumference to the outer circumference of the master disc 16.

Through the above processing, the mastering apparatus 10 can manufacture the above-described optical disk 1 by irradiating the disk base 16 with the laser beam L.

Next, referring to FIG.
A recording / reproducing apparatus 20 for recording data on the optical disc 1 or reproducing data from the optical disc 1 will be described.

The recording / reproducing apparatus 20 comprises: an optical head 21 for recording / reproducing data via a laser beam; a recording / reproducing circuit 22 for converting data into a predetermined format; , A servo circuit 24 for controlling tracking / focusing, an address detection circuit 25 for detecting an address of data read from the optical disk, and a spindle motor 26 for rotating the optical disk. Prepare.

The optical head 21 records data supplied via a system control circuit 32 and a recording / reproducing circuit 22, which will be described later, on the optical disk 1 via a laser beam. Here, the recording / reproducing circuit 22 converts the data supplied from the system control circuit 32 into a predetermined format and supplies the data to the optical head 21.

The recording / reproducing circuit 22 converts the data into, for example, sector units having a configuration as shown in FIG. 6 and records the data on the optical disk 1 via the optical head 21. The sector includes a header area formed from embossed pits,
It consists of a k-byte recording / reproducing area.

The header is composed of a sector mark (SM), synchronization timing data VFO1, VFO2, address marks (AM1, AM2), ID1, ID2, and postambles (PA1, PA2). A header 1 is formed in the groove, and a header 2 is formed in the land.
The gaps (Gap1, Gap2, Gap3) are used for switching time of a timing signal and the like. Guard
d1, Guard2) are guard areas for recording start and recording end. This guard area moves by j_ch the position of the recording data each time recording is performed, in addition to the fixed length.
As a result, the data at the recording start and recording end positions is not used, and the deterioration of the specific recording at the recording start and end positions due to overwriting is not affected by the data. Further, the number of overwrites is improved by moving the recording data position every time recording is performed. VF
O is a PLL pull-in area of the recording data. SYN
C indicates the start position of the data. Buffer is an area for absorbing the influence of jitter such as eccentricity. In one sector, the groove is formed to meander for 408 periods.

On the other hand, as shown in FIG. 7, the error correction block is composed of 64 kbytes. It can also be treated as a 2k data sector for recording and reproduction. At that time, the error correction block is recorded / reproduced in units of 64 kbytes, and desired 2 kbyte data is recorded / reproduced from the block. Specifically, for 172 bytes of data, 24
Byte parity is added. The interleave length is 384 bytes.

FIG. 8 shows the structure of a frame. The frame sync is at the beginning of each frame with dcc bits. The frame data is obtained by dividing one interleaved data of the error correction block into four pieces. Each frame is composed of 16 dcc blocks. d
The cc block includes data obtained by dividing frame data into 16 pieces, and dcc.

The optical head 21 described above outputs the detection output of the reflected light of the laser beam from the optical disk 1 to a recording / reproducing circuit 22, a servo circuit 24, an address detecting circuit 25,
It is supplied to the wobbling signal generation circuit 27.

The servo circuit 24 generates a focus error signal from the detection output of the optical head 21, and performs focusing control of the optical head 21 based on the focus error signal. Further, the servo circuit 24 includes the optical head 2
A push-pull signal is generated from the detection output of No. 1 and tracking control of the optical head 21 is performed based on the push-pull signal.

The address detection circuit 25 includes the optical head 21
After decoding the address data from the detection output of (1) and performing error detection and the like, the decoded address is supplied to the system control circuit 32.

As shown in FIG. 5, the recording / reproducing apparatus 20 includes a wobbling signal generating circuit 27 for generating a wobbling signal, a wobbling cycle detecting circuit 28 for detecting a cycle of the wobbling signal, and a PLL circuit. 29, a cluster counter 30 for counting the address position, and a ROM 3 for storing a predetermined control program.
1 and a system control circuit 32 for controlling each circuit.

The wobbling signal detection circuit 27 includes a band pass filter (BPF) 27a for removing noise components from the wobbling signal, and a comparator 27b for performing a binarization process. The BPF 27a outputs, via the optical head 21, a detection output (wobbling signal) of the wobbling of the groove recorded on the optical disc 1.
Is supplied. The BPF 27a removes the noise of the wobbling signal and supplies it to the comparator 27b. The comparator 27b performs a binarization process on the wobbling signal from the BPF 27a to obtain a wobbling detection pulse, and supplies the wobbling detection pulse to the wobbling cycle detection circuit.

The wobbling cycle detection circuit 28 determines the periodicity of the wobbling detection pulse, and supplies the same to the PLL circuit 29 if the wobbling detection pulse has a certain periodicity.

Conventionally, the wobbling cycle detection circuit 28
Cannot detect a wobbling detection pulse having a certain periodicity when synchronization is not established. However, the optical disk 1 has a groove header GRH and a land header LHG wobbled not only in the groove GR and the land but also in the address area AR1. Therefore, the wobbling cycle detection circuit 28 performs a wobbling cycle having a fixed cycle faster than before, based on the wobbling signal obtained from the address area as well as the groove and the land, even if dust adheres to the optical disc 1. A detection pulse can be obtained.

The PLL circuit 29 includes a phase comparator 29a,
A low-pass filter (LPF) 29b for removing high-frequency noise components, and a voltage-controlled oscillator (VCO) 29c
And a frequency divider 29d.

The phase comparator 29a receives the wobbling detection pulse from the wobbling cycle detection circuit 28 and the frequency divider 29
d, and compares a phase with a pulse from the VCO via the LPF 29b.
29c. The VCO 29c transmits a channel clock (hereinafter referred to as “R / W”) based on the phase comparison error signal.
Clock ". ) Is supplied to the frequency divider 29d and the cluster counter 30. The divider 29d is
The frequency division ratio is controlled by the system control circuit 32, and VC
The R / W clock from O29c is frequency-divided, a pulse having the same frequency as the frequency of the wobbling signal is generated, and supplied to the phase comparator 29a. With this processing, an R / W clock is generated based on the wobbling signal.

As described above, the PLL circuit 29 can generate an accurate R / W clock on the basis of the wobbling signal obtained from the optical disc 1, thereby enabling high-density data recording / reproduction without redundancy. Playback becomes possible. In particular, since the wobbling signal is also generated from the address area AR1, the recording / reproducing process can be performed earlier from the start of the synchronization pull-in operation than in the related art.

The cluster counter 30 performs synchronous signal processing in synchronization with the address cycle based on the address from the address detection circuit 25 and the R / W clock from the VCO 29c, and counts the position of the next address. Also,
When the position of the next address cannot be detected, the cluster counter 30 determines the position of the next address from this counter and counts up the address.

The system control circuit 32 controls the rotation of the sled motor 23 based on the address detected by the cluster counter 30 to access the optical head 21 to a predetermined position on the optical disk, and to control the cluster recording / reproducing timing. The recording and / or reproduction processing of data is performed in accordance with. The ROM 31 stores the data of the frequency division ratio of the frequency divider 29 d corresponding to the address, and the system control circuit 32 controls the frequency division ratio of the frequency divider 29 d based on the data of the ROM 31. Then, the system control circuit 32
Controls the recording / reproducing circuit 22, performs predetermined signal processing on data read from the optical head 21, and outputs the processed data to the outside. Optical disk 1 via head 21
To record.

As described above, the recording / reproducing apparatus 20 comprises:
Since the wobbling signal can be detected and synchronized based on the groove header GRH and the land header LH as well as the groove GR, it is possible to more quickly and stably specify the address position, that is, the position of the optical head 21. it can. Also, the spindle motor 26 can be controlled to rotate more quickly and stably.

For example, even if the influence of dust adhering to the optical disk 1 becomes so great that the information in the address area cannot be read out, the groove header GRH and the land header LH from the groove GR and the land, and further from the address area. , A correct clock can be obtained from the synchronization information of the wobbling signal, and the respective circuits can be synchronized.

In other words, the error correction capability of the address area may be low, so that an efficient format can be formed.

[0057]

As described above in detail, according to the clock generating apparatus and the clock generating method of the present invention, the wobbling signal corresponding to the meandering shape of the groove and the embossed pit of the groove header is detected and detected. By generating a clock based on a constant wobbling signal, a high-speed and stable clock can be generated and synchronized.

According to the optical disc of the present invention, in the address area, the embossed pits of the groove header are formed on the extension of the groove and meandering in the same cycle and in the same phase as the groove meandering. A high-speed and stable clock can be generated.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an optical disc to which the present invention is applied.

FIG. 2 is a configuration diagram of each sector of the optical disc.

FIG. 3 is a configuration diagram of each sector of a land / groove recording type optical disc.

FIG. 4 is a block diagram showing a configuration of a mastering device for manufacturing the optical disc.

FIG. 5 is a block diagram showing a configuration of the optical disk recording / reproducing apparatus.

FIG. 6 is a configuration diagram of a sector recorded on the optical disc.

FIG. 7 is a configuration diagram of an ECC block recorded on the optical disc.

FIG. 8 is a configuration diagram of a frame recorded on the optical disc.

[Explanation of symbols]

1 optical disc, 21 optical head, 27 wobbling signal generation circuit, 28 wobbling cycle detection circuit, 29
PLL circuit

Claims (7)

[Claims] 1. An address area and a user area are assigned to each sector. In the user area, a groove is formed meandering, and a land is formed correspondingly in a meandering manner. An optical disc which irradiates a laser beam to an optical disc in which the embossed pits of the header are formed on the extension of the groove and meander with the same period and the same phase as the meander of the groove, and detect the reflected light. A wobbling signal detecting means for detecting a wobbling signal corresponding to the meandering shape of the grooves and the embossed pits of the groove header based on a detection output of the optical head; and A clock generation device comprising: a clock generation unit that generates a clock. 2. The optical head according to claim 1, wherein an address area and a user area are assigned to each sector. In the user area, a groove is formed in a meandering manner, and a land is formed in a corresponding manner in a meandering manner. In the area, the embossed pits of the groove header are formed on the extension of the groove and meander in the same cycle and in the same phase as the meandering of the groove, and the embossed pits of the land header are formed on the extension of the land in the address area. A laser beam is applied to the optical disk formed with the same period as the meandering of the land and inverted in phase, and the reflected light is detected. The wobbling signal detection means outputs the detection output of the optical head. The meandering shape of the groove, the groove header and the land header based on Clock generating apparatus according to claim 1, wherein the detecting a wobbling signal corresponding to. 3. An address area and a user area are assigned to each sector. In the user area, a groove is formed in a meandering manner, and a land is formed in a corresponding manner in a meandering manner. Embossed pits of the header are on an extended line of the groove and formed on the optical disk formed to meander in the same cycle and in the same phase as the groove meandering, and irradiate a laser beam to detect the reflected light thereof, Detecting a wobbling signal corresponding to the meandering shape of the groove and the embossed pits of the groove header based on the detection output of the reflected light, and generating a clock based on the detected wobbling signal having a constant period. Clock generation method. 4. An address area and a user area are allocated for each sector. In the user area, a groove is formed in a meandering manner, and a land is formed in a corresponding manner in a meandering manner. The embossed pits are formed on the extension of the groove and meander in the same cycle and in the same phase as the meandering of the groove. In the address area, the embossed pits of the land header are on the extension of the land and are formed on the land. A laser beam is applied to an optical disc formed with the same cycle as the meandering and inverted in phase to detect a reflected light thereof, and the groove, the groove header and the groove header are detected based on a detection output of the reflected light. The wobbling signal corresponding to the meandering shape of the land header is detected, and the detected The clock generation method according to claim 3, characterized in that the generating a clock based on the wobbling signal. 5. A data recording surface is divided into radial areas to form a plurality of sectors. Each sector is assigned to an address area and a user area. In the user area, grooves are formed meandering. Correspondingly, the lands also meander, and in the address area, the embossed pits of the groove header are formed on the extension of the groove and meander with the same period and the same phase as the meander of the groove. An optical disc characterized by the above-mentioned. 6. The address area, wherein embossed pits of a land header are formed on an extension of the land and have the same period and inverted phase as the meandering of the land. An optical disc as described. 7. The optical disk according to claim 6, wherein data is recordable or data is recorded in the grooves and lands of the user area.