JP3775431B1 - CLOCK GENERATION DEVICE, CLOCK GENERATION METHOD, AND OPTICAL DISC - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve high speed and stable synchronization even if dust adheres to an optical disk.
A groove header GRH is formed in the first half of an address area AR1, and a land header LH is formed in the second half thereof. The pit row of the groove header GRH is formed by wobbling on the extension line of the groove GR and in the same cycle and the same phase as the wobbling. The pit row of the land header LH is formed on the extension line of the wobbling land and has the same period as the wobbling of the groove GR, but is inverted and wobbled.
[Selection] Figure 3

Description

  The present invention relates to a clock generation device and the like for generating a synchronization signal from an optical disc.

  As a method for forming an address on an optical disc, it is known to form pits in advance when embossing an optical disc.

  In an optical disc, for example, each user data 2048 bytes, which is a recording / reproduction unit, is divided into blocks as sectors, and a sector address as a header is formed at the head of the sector.

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

JP-A-8-321076

  Nowadays, an optical disc cover with a very thin thickness has been proposed. For example, when the thickness of the cover of the optical disk is about 0.1 t (= 0.1 [mm]), some influence is often caused by dust adhering to the surface of the optical disk.

  For example, data recorded in the user area may cause an error due to adhesion of dust. However, it is possible to avoid the occurrence of the error by increasing the redundancy and enhancing the error correction capability.

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

  The present invention has been proposed in view of such circumstances, and provides a clock generation device, a clock generation method, and an optical disc that can achieve high speed and stable synchronization even if dust adheres to the optical disc. For the purpose.

  In order to solve the above-described problems, the clock generation device according to the present invention has an address area and a user area assigned to each sector, and the user area is formed with meandering grooves, and correspondingly the land. In the address area, the emboss pits of the groove header are formed by meandering on the extension line of the groove and in the same period and in the same phase as the groove meander, and the embossing of the land header The pits are formed on the extended line of the land and have the same period and phase as those of the meandering of the land, and the embossed pits of the groove header and the embossed pits of the land header generate wobbling signals having opposite phases to each other. Irradiate a laser beam to an optical disk that is formed to give An optical head for detecting the reflected light of the optical head, and a wobbling signal detecting means for detecting a wobbling signal corresponding to the meandering shape of the embossed pits of the groove, the groove header and the land header, based on the detection output of the optical head, And a clock generation means for generating a clock based on the detected wobbling signal having a constant period.

  Further, in the clock generation method according to the present invention, an address area and a user area are assigned to each sector, and in the user area, a groove is meandered and a land is meandering correspondingly, In the address area, the emboss pit of the groove header is formed by meandering on the extension line of the groove and in the same period and in the same phase as the meander of the groove, and the emboss pit of the land header is an extension of the land. The groove is formed with the same period and phase reversed as the meandering of the land, and the embossed pits of the groove header and the embossed pits of the land header are formed so as to give wobbling signals having opposite phases to each other. The optical disk is irradiated with a laser beam and the reflected light is detected. Based on the detection output of the reflected light, a wobbling signal corresponding to the meandering shape of the emboss pits of the groove, the groove header, and the land header is detected, and a clock is generated based on the detected wobbling signal having a constant period. It is characterized by.

  Furthermore, the optical disc according to the present invention is formed by dividing the data recording surface into radial areas to form a plurality of sectors, each sector being assigned to an address area and a user area, and a groove meandering in the user area. Correspondingly, the land is also meandered, and in the address area, the embossed pits of the groove header meander on the extension line of the groove with the same period and the same phase as the meandering of the groove. The emboss pit of the land header is formed on the extended line of the land and with the same period and phase as the meander of the land, and the emboss pit of the groove header and the emboss of the land header are formed. That the pits are shaped to give wobble signals that are out of phase with each other. And butterflies.

  As described above in detail, according to the clock generation device and the clock generation method according to the present invention, the groove and the emboss pits of the land header and the land header formed so as to give the wobbling signals in opposite phases to each other. By detecting a wobbling signal corresponding to the meandering shape and generating a clock based on the detected wobbling signal having a constant period, it is possible to generate a high-speed and stable clock and achieve synchronization.

  According to the optical disc of the present invention, in the address area, the emboss pits of the groove header are formed by meandering with the same period and the same phase as the meandering of the groove on the extension line of the groove, and the embossing of the land header. The pits are formed on the extended line of the land and have the same period and phase as those of the meandering of the land, and the embossed pits of the groove header and the embossed pits of the land header generate wobbling signals having opposite phases to each other. By being formed so as to give, a high-speed and stable clock can be generated.

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

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

  In the optical disc 1, the data recording surface is divided into radial regions 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 AR2 to which normal data is written is allocated to the remaining area. 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, lands are 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 period, and the number of meanders of the groove GR is sequentially increased as it moves to the outer zone. The groove GR is formed in a so-called zone CAV (Constant Liner Velocity) shape. The address area AR1 is discretely arranged on the optical disc, and sector unit address information is recorded. In the address area AR1, a length corresponding to a certain period of the groove GR is assigned.

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

  Thereby, synchronization information (a wobbling signal) is obtained when the laser beam irradiates a groove (for example, position A) of the user area AR2, and the irradiation position is changed from the user area AR2 to the address area AR1 (for example, position B). ), The same wobbling signal can be obtained from the groove header GRH.

  In the land / groove recording type optical disc, 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 thereof. The pit row of the groove header GRH is formed by wobbling with the same period and the same phase as the wobbling on the extension line of the groove GR, similarly to the above-described groove recording method. On the other hand, the pit row of the land header LH is on the extension line of the wobbling land described above. In addition, the pit row of the land header LH is formed by wobbling with the phase being reversed but having the same period as the wobbling of the groove GR. Here, the phase of the pit row of the land header LH is inverted because the wobbling signal obtained from the reflected light of the groove GR and the wobbling signal obtained from the reflected light of the land are different from each other by π. is there.

  Thus, as in the case of the groove recording method, a wobbling signal is obtained when the laser beam is irradiating the groove GR (for example, position C) of the user area AR2, and the irradiation position is addressed from the user area AR2. Even when the area AR1 (for example, position D) is changed, the same wobbling signal can be obtained from the groove header GRH. Further, the same wobbling signal can be obtained even when the irradiation position of the laser beam passes through the pit row of the groove header GRH and moves between the pit rows of the land header LH (for example, position E). The optical disc 1 is manufactured by exposing a master disc by a mastering device 10 having a configuration shown in FIG. 4, for example.

  The mastering device 10 combines a signal from the wobble signal generation circuit 11 and the address signal generation circuit 12 and outputs a drive signal SD, and a drive circuit that drives the optical head 15 based on the drive signal SD. 14, a spindle motor 17 that rotationally drives the disk master 16, and a system control circuit (not shown).

  The wobble signal generation circuit 11 outputs a sine wave signal having a predetermined frequency synchronized with the rotation of the disk master 16 as a wobble signal WB. Further, the wobble signal generation circuit 11 increases the frequency of the wobble signal WB in a stepwise manner and outputs it in response to zoning. Thus, the wobble signal generation circuit 11 displaces the laser beam irradiation position by the wobble signal WB and causes the groove GR to 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).

  Specifically, the address signal generation circuit 12 receives a timing signal composed of an FG signal or the like synchronized with the rotation of the disk master 16 from the spindle motor 17 or the like, counts this timing signal with a predetermined counter, and performs laser beam irradiation. An address data ID indicating the position is generated. At this time, the address signal generation circuit 12 adds the sector mark SM, the timing data VFO for synchronization, the address mark AM, and the postamble PA to the address data ID, and respectively in the first half and the second half of the address area AR1. A groove header GRH to be allocated and a land header LH as necessary are generated. At this time, the groove header GRH is wobbled with the same period and the same phase as the wobbling of the groove GR, and the land header LH is wobbled so that the phase thereof is inverted. As the synchronization timing data VFO, the same clock pattern as the clock pattern recorded / reproduced as the synchronization timing data VFO is generated at the head portion of the user area AR2. The address signal generation circuit 12 converts the sector header generated in this way into a serial data string, and modulates this serial data string with a predetermined format.

  Then, the address signal generation circuit 12 supplies this modulation output to the synthesis circuit 13 as the 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 zoning the disc master 16 by switching the driving condition of the optical head 15 according to the laser beam irradiation position at the timing synchronized with the rotation of the disc master 16. Specifically, the drive circuit 14 switches the drive conditions of the optical head 15 so that the information recording surface of the disk master 16 is divided into radial areas to form a sector structure. Further, by changing the switching timing stepwise from the inner circumference side to the outer circumference side, the information recording surface is divided into concentric circles to form a plurality of zones Z0 to Zn.

  Further, the drive circuit 14 is formed by displacing the laser beam irradiation position by the drive signal SD in the user area AR2 according to the control of the system control circuit, thereby causing the groove GR to meander in the user area AR2.

  In the address area AR1, the displacement of the laser beam irradiation position is stopped in the first half of the address area AR1, and the light amount of the laser beam is intermittently raised by the drive signal SD, whereby a pit is formed on the track center by the groove GR. Form a row. Further, in the latter half of the address area AR1, the laser beam irradiation position is displaced onto the track center by the inner land, and the light quantity 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. Form.

  At this time, the driving circuit 14 records the address data of the sector by the following groove GR on the track center in the first half side of the address area AR1, and records the address data on the track center in the second half side of the address area AR1. The address data of the sector by the land 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 disk master 16. Further, when the optical head 15 creates an optical disk from the disk master 16, the laser beam L so that the width of the land between the groove GR formed by the exposure of the laser beam L and the adjacent groove GR becomes substantially equal. The spot diameter is set. Here, the spot shape and the light amount of the laser beam L are set so that the effective exposure range by the laser beam L is expanded with respect to the width of the groove GR which is the final target. Therefore, the optical head 15 exposes the disc master 16 so that the optical disc created by the disc master 16 can be recorded between the land / groove GR.

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

  Through the processing as described above, the mastering apparatus 10 can produce the optical disc 1 described above by irradiating the disc substrate 16 with the laser beam L.

  Next, a recording / reproducing apparatus 20 that records data on the optical disc 1 or reproduces data on the optical disc 1 will be described with reference to FIG.

  The recording / reproducing apparatus 20 includes an optical head 21 that records / reproduces data via a laser beam, a recording / reproducing circuit 22 that converts data into a predetermined format, and moves the optical head 21 in the radial direction of the optical disk. A sled motor 23 for controlling the tracking / focusing, an address detecting circuit 25 for detecting an address of data read from the optical disc, and a spindle motor 26 for rotating the optical disc.

  The optical head 21 records data supplied via a system control circuit 32 and a recording / reproducing circuit 22 described later on the optical disc 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 then supplies the data to the optical head 21.

  The recording / reproducing circuit 22 converts the data into sector units configured as shown in FIG. 6, for example, and records the data on the optical disc 1 via the optical head 21. The sector is composed of a header area formed from embossed pits and an 8 kbyte 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, and Gap3) are used for timing signal switching time and the like. The guard (Guard1, Guard2) is a guard area at the start and end of recording. In addition to a certain length, this guard area moves the position of the recording data j_ch every time recording is performed. As a result, data at the recording start and recording end positions is not used, and the recording start and end position specific recording deterioration due to overwrite is not affected by the data. Further, the number of overwriting is improved by moving the recording data position for each recording. VFO is a PLL pull-in area for recording data. SYNC indicates the start position of data. Buffer is an area that absorbs the influence of jitter such as eccentricity. In one sector, the groove is formed to meander for 408 periods.

  On the other hand, the error correction block is configured in units of 64 kbytes as shown in FIG. It can also be handled as a recording / reproducing 2k data sector. At that time, the error correction block is recorded and reproduced in units of 64 kbytes, and desired 2 kbyte data is recorded and reproduced. Specifically, 24-byte parity is added to 172-byte data. The interleave length is 384 bytes.

  FIG. 8 shows a frame configuration. The frame sync is at the beginning of each frame along with the dcc bit. The frame data is obtained by dividing one interleave data of an error correction block into four pieces. Each frame is composed of 16 dcc blocks. The dcc block is composed of data obtained by dividing frame data into 16 pieces and dcc.

  Further, the optical head 21 described above supplies the detection output of the reflected light of the laser beam from the optical disk 1 to the recording / reproducing circuit 22, servo circuit 24, address detection circuit 25, and 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. The servo circuit 24 generates a push-pull signal from the detection output of the optical head 21, and performs tracking control of the optical head 21 based on the push-pull signal.

  The address detection circuit 25 decodes the address data from the detection output of the optical head 21, detects an error, etc., and then supplies the decoded address to the system control circuit 32.

  Further, as shown in FIG. 5, the recording / reproducing apparatus 20 includes a wobbling signal generation circuit 27 that generates a wobbling signal, a wobbling period detection circuit 28 that detects a period of the wobbling signal, a PLL circuit 29, A cluster counter 30 that counts address positions, a ROM 31 that stores a predetermined control program, and a system control circuit 32 that controls each circuit are provided.

  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 binarization processing. The BPF 27 a is supplied with the detection output (wobbling signal) of the groove wobbling recorded on the optical disc 1 through the optical head 21. The BPF 27a removes noise from the wobbling signal and supplies it to the comparator 27b. The comparator 27 b performs binarization processing on the wobbling signal from the BPF 27 a to obtain a wobbling detection pulse, and supplies the wobbling detection pulse to the wobbling period detection circuit 28.

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

  Conventionally, the wobbling period detection circuit 28 cannot detect a wobbling detection pulse having a certain periodicity when synchronization is not established. However, the optical disc 1 is formed with a groove header GRH and a land header LHG that are wobbled not only in the groove GR and land but also in the address area AR1. Therefore, the wobbling period detection circuit 28 is based on the wobbling signal obtained from the address area as well as the groove and land, and even if dust is attached to the optical disc 1, the wobbling period detecting circuit 28 has a constant period faster than the prior art. A detection pulse can be obtained.

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

  The phase comparator 29a compares the phases of the wobbling detection pulse from the wobbling period detection circuit 28 and the pulse from the frequency divider 29d, and supplies a phase comparison error signal indicating the phase error to the VCO 29c via the LPF 29b. To do. The VCO 29c generates a channel clock (hereinafter referred to as “R / W clock”) based on the phase comparison error signal, and supplies it to the frequency divider 29d and the cluster counter 30. The frequency divider 29d has a frequency division ratio controlled by the system control circuit 32, divides the R / W clock from the VCO 29c, generates a pulse having the same frequency as the frequency of the wobbling signal, and supplies the pulse 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 based on the wobbling signal obtained from the optical disc 1, thereby enabling recording / reproduction of data with high density without redundancy. become. In particular, since the wobbling signal is also generated from the address area AR1, the recording / reproducing process can be performed earlier than the start of the synchronous pull-in operation as compared with the conventional case.

  Based on the address from the address detection circuit 25 and the R / W clock from the VCO 29c, the cluster counter 30 performs synchronization signal processing synchronized with the address cycle and counts the position of the next address. Further, when the cluster counter 30 cannot detect the position of the next address, 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, accesses the optical head 21 to a predetermined position on the optical disk, and matches the cluster recording / reproduction timing. Data recording and / or reproduction processing is performed. Further, the ROM 31 stores data of the frequency division ratio of the frequency divider 29d corresponding to the address, and the system control circuit 32 controls the frequency division ratio of the frequency divider 29d based on the data of the ROM 31. Then, the system control circuit 32 controls the recording / reproducing circuit 22 to perform predetermined signal processing on the data read from the optical head 21 and output the data to the outside. The data is converted into a format and recorded on the optical disk 1 via the optical head 21.

  As described above, the recording / reproducing apparatus 20 can detect and synchronize the wobbling signal based not only on the groove GR but also on the groove header GRH and the land header LH. That is, the position of the optical head 21 can be specified. 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 disc 1 becomes large and information of the address area cannot be read as a result, the wobbling signal is sent from the groove GR or land, and further from the groove header GRH or land header LH in the address area. Therefore, an accurate clock can be obtained from the synchronization information of the wobbling signal, and each circuit 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.

It is a block diagram of the optical disk to which this invention is applied. It is a block diagram of each sector of the optical disc. It is a block diagram of each sector of the land / groove recording type optical disc. It is a block diagram which shows the structure of the mastering apparatus which produces the said optical disk. It is a block diagram which shows the structure of the recording / reproducing apparatus of the said optical disk. It is a block diagram of the sector currently recorded on the said optical disk. It is a block diagram of the ECC block currently recorded on the said optical disk. It is a block diagram of the flame | frame currently recorded on the said optical disk.

Explanation of symbols

  1 optical disk, 21 optical head, 27 wobbling signal generation circuit, 28 wobbling period detection circuit, 29 PLL circuit

Claims (4)

An address area and a user area are assigned to each sector. In the user area, grooves are meandered, and lands are meandered correspondingly. In the address area, emboss pits in the groove header are formed. The land header embossed pits are on the land extension line and have the same period as the land meander. In addition, a laser beam is applied to an optical disc formed so that the phase is inverted and the emboss pits of the groove header and the emboss pits of the land header give wobbling signals having opposite phases to each other. An optical head for detecting the reflected light;
Wobbling signal detection means for detecting a wobbling signal corresponding to the meandering shape of the emboss pits of the groove, the groove header, and the land header based on the detection output of the optical head;
A clock generation device comprising: clock generation means for generating a clock based on a detected wobbling signal having a constant period. An address area and a user area are assigned to each sector. In the user area, grooves are meandered, and lands are meandered correspondingly. In the address area, emboss pits in the groove header are formed. The land header embossed pits are on the land extension line and have the same period as the land meander. In addition, a laser beam is applied to an optical disc formed so that the phase is inverted and the emboss pits of the groove header and the emboss pits of the land header give wobbling signals having opposite phases to each other. Detect the reflected light,
Based on the detection output of the reflected light, a wobbling signal corresponding to the meandering shape of the emboss pits of the groove, the groove header, and the land header is detected,
A clock generation method comprising: generating a clock based on a detected wobbling signal having a constant period. A plurality of sectors are formed by dividing the data recording surface into radial areas,
Each sector is assigned to an address area and a user area,
In the above user area, the groove is meandering and the land is meandering correspondingly,
In the address area, the emboss pit of the groove header is formed by meandering on the extension line of the groove and in the same period and in the same phase as the meander of the groove, and the emboss pit of the land header is an extension of the land. The groove is formed with the same period and phase reversed as the meandering of the land, and the embossed pits of the groove header and the embossed pits of the land header are formed so as to give wobbling signals having opposite phases to each other. An optical disc characterized by the above.   4. The optical disk according to claim 3, wherein the grooves and lands in the user area can record data or data is recorded.

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