JPH05266595A - Recording/reproducing method and optical disk device using same method - Google Patents

Abstract

PURPOSE:To enable many information recordings and to reduce a burden on a recording/reproducing system by dividing tracks on a medium into plural zones and changing the revolving speed of the medium at every zone. CONSTITUTION:A disk where a servo area and a data area on the tracks are arranged in a radial direction linearly is divided into zones at every plural tracks. A zone number from a track address to be accessed is identified by a zone identification circuit 118 and by this, signals are generated for changing the revolving speed of a spindle motor 102 and the divisive number of a data clock generation circuit 10. First, the revolving speed of the motor 102 is changed at every zones by the former signal and controlled by a motor control circuit 116 so that a constant speed is maintained on a whole surface. Also, the divisive number of the circuit 110 is changed by the latter signal and the recording/reproducing clock is maintained at a constant frequency. That is, even though a clock mark emerging interval is changed as well by the changed of the rotative number, the original oscillation frequency of a PLL is maintained constant by changing the divisive number of the PLL of the circuit 110.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is a so-called sample in which a clock signal generating means, for example, a clock mark is intermittently provided on a track of an optical disk, and the clock mark is detected to perform recording / reproducing and tracking control of the signal. The present invention relates to a servo type optical disc device and a recording / reproducing method of the device, and more particularly to a format configuration and a device suitable for increasing a storage capacity.

[0002]

2. Description of the Related Art An optical disk device has been developed as an information storage device capable of recording, reproducing or erasing data on a high recording density rotary recording medium.

An optical disc, which is a rotary recording medium, is provided with a large number of tracks concentrically or spirally at a constant pitch, and data is recorded on these tracks. When reproducing, erasing or recording data, focus control for keeping the focus of the light spot on the recording surface of the optical disc, tracking control for making the light spot follow the track, or access control for selecting the track from which data is to be recorded is necessary.

A so-called "sample servo" has been proposed as a method for obtaining servo signals such as a focus shift signal, a track shift signal for controlling these, or a light spot movement signal for accessing. In the sample servo system, for example, 5 inches of Japanese Industrial Standard (JIS
-X6271), the B format has a servo area for detecting a servo signal for each constant angle of the optical disc, and a data area for recording data is provided between the servo areas. .. A clock mark for generating a clock signal is provided in the servo area, and a focus shift signal, a track shift signal, or an optical spot movement signal for access is detected based on the clock signal obtained by the clock mark. , Focus control, tracking control, and access control. Also,
The same clock is also used for recording and reproducing data.

The track shift signal is generated from the difference in the amount of reflected light when a light spot passes through two wobble marks facing each other with the track center interposed therebetween. Therefore, there is an advantage that the detection optical system can be simplified. In addition, the servo area and data area are separated, and signal detection is performed in a time-division manner so that they do not interfere with each other.Using a single clock that synchronizes servo signal detection and data recording / reproduction with clock marks There is a feature that can be done.

A set of a servo area and a data area is called a segment. Some of this segment gathered,
Make up a sector. The address of the track is recorded at the beginning of the sector, and this portion is called the header.
The heads of servo areas, data areas, or segments and sectors where these areas are gathered are linearly aligned in the radial direction. The clock marks in the servo area are also linearly arranged in the radial direction. Since the optical disk rotates at a constant angular velocity, clock marks appear at equal time intervals. From the point of rotating at a constant angular velocity, CA
It is called a V (constant angular velocity) method.

In contrast to the CAV system, there is a system called CLV (constant linear velocity) system in which the rotational speed of the disk is changed depending on the track position so that the linear velocity is always constant. For example, this is used in DAD (Digital Audio Disc) and the like. In the CLV method, for example, data can be continuously written from the inner circumference at the same pitch, and the storage capacity can be increased. Further, since the linear velocity is constant, the load on the recording / reproducing system can be reduced, and a medium having a small recording power margin can be used.

[0008]

In the CAV type sample servo, the length of the circumference becomes longer toward the outer side of the disk. Therefore, both the servo area and the data area become longer toward the outer circumference in proportion to the radius. .. Therefore, the physical interval between the data pits in the servo area and the data area is the shortest at the inner circumference and becomes wider toward the outer circumference.

Further, since the CAV system rotates at a constant angular velocity, the linear velocity is different between the inner circumference and the outer circumference. Therefore, since the setting of the recording condition when recording the data is different between the inner and outer circumferences, the setting must be finely changed depending on the track position. In addition, there is a problem that a wide margin is required to obtain an optimum recording state, and demand for the medium becomes severe.

In order to avoid these problems, the CLV system may be used instead of the CAV system. However,
Problems arise when the CLV method is used for sample servo.
For example, if the packing is continuously performed from the innermost circumference, the length of the circumference becomes longer as it goes to the outer circumference. Therefore, the positions of the servo area and the data area are not aligned linearly in the radial direction with respect to the disk, and the positions of the clock marks in the servo area are also shifted between adjacent tracks. If this happens, when an access operation is performed in which the light spot crosses the tracks, the time intervals at which the clock marks appear will be scattered, and the clock synchronization will be lost. In the sample servo, a servo signal such as a focus shift signal, a track shift signal, or an optical spot movement signal for access is detected using a clock synchronized with the clock mark, so the access operation itself becomes impossible. I will end up.

An object of the present invention is to provide an optical disc apparatus using a sample servo which has a format structure capable of recording more information and reducing the load on a recording / reproducing system or a recording medium. To provide.

[0012]

In order to solve the above problems, in a disk in which servo areas and data areas on tracks are linearly aligned in the radial direction, a plurality of tracks are divided into zones. A circuit for identifying the zone to which the track belongs from a track address signal or an access destination address number is provided, and a circuit for controlling the rotation speed of the spindle motor is provided to change the rotation speed of the disk for each zone. Further, the servo clock generating means and the data clock generating means are separately provided, and the servo signal detection and the data recording / reproducing are performed by different clocks and timing signals. The data clock generation means can change the internal division ratio for each identified zone and change the amount of data recorded in the data area for each zone.

[0013]

The zone number is identified from the track address of the present or the access destination, and a signal for changing the rotation number of the spindle motor and the division number of the data clock generating circuit is generated from the zone number. First, based on the former signal, the rotation speed of the spindle motor is changed for each zone, and the rotation speed is changed so that the disk has a substantially constant linear velocity. That is, the inner peripheral zone has a high rotational speed, and the outer peripheral zone has a slow rotational speed. Further, by changing the number of divisions of the data clock generation circuit based on the latter signal, the recording / reproducing clock has a constant frequency. That is, since the disk rotation speed changes depending on the zone, the interval at which the clock mark appears also changes. However, by changing the number of divisions of the PLL in the data clock generation circuit, even if the interval at which the clock mark appears changes, the original PLL Make sure that the oscillation frequency does not change.

Since the linear velocity on the disk is almost constant and the frequency of the recording / reproducing clock is also constant, the bit pitch of the data is almost constant. On the other hand, since the servo area and the data area are linearly aligned in the radial direction, the physical interval of the data area becomes longer toward the outer zone. Therefore, the amount of data in one data area increases in the outer zone.

The servo area also becomes longer toward the outer peripheral zone, and the pitch of the servo data in the servo area also becomes longer. Further, since the rotation speed of the disk becomes slower in the outer peripheral zone, the frequency of the clock for reproducing servo data also needs to be lowered. Since the number of divisions of the PLL in the servo clock generation circuit is fixed, the original oscillation frequency of the PLL changes according to the change in the appearance interval of the clock mark, and the clock for reproducing servo data also changes. That is, in the zone on the outer peripheral side, the rotation speed of the disk decreases and the appearance interval of the clock mark also increases, so that the frequency of the clock for reproducing servo data also decreases accordingly. If this clock is used, servo data can be reproduced.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in more detail based on the embodiments shown in the drawings. Although a phase change medium is used as a medium for recording / reproducing in this embodiment, the present invention is not limited to this.

FIG. 1 is a block diagram of an embodiment of the optical disk device of the present invention.

The optical disc 100 includes a spindle motor 1
Driven by 02. Further, on the optical disc 100, a means for generating a clock at a constant angle, for example, a clock mark, a means for obtaining a track deviation signal using timing from the clock, for example, a wobble mark, and an optical signal using timing from the clock are used. Means for obtaining information on the position or movement amount of the spot, such as an access code, is provided. The laser beam from the optical head 104 is focused on the optical disc 100,
Connect the light spots. The reflected light from the optical disc 100 is again guided into the optical head 104 and converted into an electric signal by the detector. This electric signal is the signal detection circuit 106.
Then, a signal Sa representing the total amount of reflected light and a signal Sd representing the amount of defocus are generated.

When the light spot passes over the clock mark, the reflected light total light amount signal Sa changes. The total light amount signal Sa is guided to the servo clock generation circuit 108. The PLL in the servo clock generation circuit 108 generates a clock and timing signal Ts for servo signal detection and a clock fcms for controlling the rotation of the spindle motor in synchronization with the clock mark. The total light amount signal Sa is also led to the data clock generation circuit 110. The PLL in the data clock generation circuit 110 is also synchronized with the clock mark, and the clock and timing signal T for data recording / reproduction is used.
d, a clock fcmd for controlling the rotation of the spindle motor is generated.

To the servo signal detection circuit 112, the total light amount signal Sa generated by the signal detection circuit 106 and the signal Sd representing the amount of defocus, the clock for servo signal detection generated by the servo clock generation circuit 108, and The timing signal Ts is input. In the servo detection circuit 112, Ts
Based on Sa and Sd, a track shift signal, a focus shift signal, and an address signal A representing the position of the light spot are obtained.
d, a signal indicating the movement amount of the light spot, a signal indicating the movement speed of the light spot, and the like are generated. These signals are sent to the servo control circuit 114. Servo control circuit 11
In 4, a drive signal for performing focusing, tracking, and accessing is generated by using a signal from the servo signal detection circuit 112 based on a command from the host control circuit, and a mechanism such as a focus actuator, a tracking actuator, and an accessor is driven. .. Further, based on a command from the host control circuit, a command Sm is sent to the motor control circuit 116 to start and stop the spindle motor 102.

The zone identification circuit 118 identifies the zone in which the optical spot is currently located from the address signal Ad from the servo signal detection circuit 112, generates the zone number Nz corresponding to the zone, and outputs the data clock generation circuit 1
10 and the motor control circuit 116. The motor control circuit 116 changes the reference clock division number according to the division number Nz, and the synchronization clock fcms from the servo clock generation circuit 108 or the data clock generation circuit 1 is changed.
The synchronous clock fcmd from 10 is used to change the rotational speed of the motor. In the data clock generation circuit 110, the frequency division ratio of the PLL is changed based on the division number Nz so that the data recording / reproducing clock and the timing signal Td having a substantially constant frequency can be obtained even if the rotation speed changes.

The data reproducing circuit 120 receives the total light amount signal Sa from the signal detecting circuit 106. In the present embodiment, since the phase change medium is used, the data signal can be reproduced from the reflected light quantity total light quantity Sa. However, for example, when the magneto-optical medium is used, the data reproduction circuit 120 has the total light quantity signal S.
A magneto-optical signal enters instead of a. Data reproduction circuit 120
Then, data is extracted from the total light amount signal using the data recording / reproducing clock and the timing signal Td from the data clock generating circuit 110, and demodulation is performed based on the modulation / demodulation rule. The demodulated data is sent to the error correction circuit 122, and the data is error-corrected by using, for example, an ECC (error correction code). The error-corrected data is sent to the host device through the input / output interface. On the contrary, when the data to be recorded is sent from the host device through the input / output interface, the error correction circuit 122 adds an ECC for error correction to the data,
It is sent to the data recording circuit 124. Data recording circuit 124
Then, the data is modulated based on the modulation and demodulation rule, and is recorded on the optical disc 100 through the optical head 104 based on the data recording / reproducing clock from the data clock generating circuit 110 and the timing signal Td.

FIG. 2A shows a conventional CAV (constant angular velocity).
2B is a schematic diagram showing the state of the optical disk in the case where the CLV (constant linear velocity) method is directly adopted as the sample servo optical disk, by enlarging the segment structure. .. The segment, which is the minimum unit for recording and reproducing data, is a servo area in which servo information such as clock marks, wobble marks, and access codes is preformatted,
It is composed of a data area in which data can be recorded, reproduced, or erased. Actual segment length is tens
The length is μm, but it is enlarged for easy understanding.

In the CAV type sample servo shown in FIG. 2A, the circumference becomes longer toward the outer side of the disk. Therefore, both the servo area and the data area become longer in proportion to the radius toward the outer circumference. .. Further, the servo area and the data area are linearly aligned in the radial direction with respect to the disk. Since this disk is rotated and used at a constant angular velocity, the time interval at which the servo area appears, more strictly speaking, the cycle at which the clock mark appears is constant,
The cycle is the same regardless of which track the disk is on. The sample servo synchronizes the PLL with the clock mark appearing in this fixed cycle, and creates various clocks or timing signals from the PLL to record / reproduce data. Hereinafter, the physical length becomes longer in proportion to the radius, and a clock having a constant frequency is obtained when the disc is rotated at a constant angular velocity, and the recording / reproducing timing is taken by the clock is called CAV mode. I will.

However, in this method, the physical interval of the data pits is the shortest at the inner circumference and widens toward the outer circumference. If the outer pit spacing can be reduced, more information can be recorded on the same disc. Further, in the CAV method, since the linear velocities are different between the inner circumference and the outer circumference, the setting of recording conditions when recording data is different between the inner circumference and the outer circumference, and therefore the setting must be finely changed depending on the track position. Also,
There is a problem that a wide margin is required to obtain an optimum recording state, and demand for the medium becomes severe.

On the other hand, there is a so-called CLV (constant linear velocity) system in which the rotational speed of the disk is changed depending on the track position so that the linear velocity is always constant. For example, this is a DAD (Digital Audio Disc)
It is used in etc. FIG. 2B shows an example in which the CLV method is used for sample servo. The servo area and the data area are physically the same length regardless of the position.
This is a method of continuously packing these from the innermost circumference or the outermost circumference of the disk. Since this disk is rotated and used at a constant linear velocity, the time interval at which the servo area appears, more strictly speaking, the cycle at which the clock mark appears is constant. Instead, in order to keep the linear velocity constant, the rotational speed of the disk must be changed depending on the radial position of the head. In the sample servo, synchronizes the PLL with the clock mark that appears in this constant cycle,
Data is recorded and reproduced by generating various clock or timing signals from L. In the following description, a CLV mode is one in which the physical lengths are the same regardless of the radii, and a clock having a constant frequency is obtained when the disc is rotated at a constant linear velocity, and the recording / reproducing timing is determined by the clock. To do. If this method is used, the physical length of the servo area and data area, and more specifically, the data pits in them, can be made constant on any track and made as short as possible, thus increasing the storage capacity. You can

However, a problem arises when the CLV method is used for sample servo. For example, if the packing is continuously performed from the innermost circumference, the length of the circumference becomes longer as it goes to the outer circumference. Therefore, as shown in FIG. 2B, the positions of the servo area and the data area are not aligned linearly in the radial direction with respect to the disk. Further, the position of the clock mark in the servo area also shifts between adjacent tracks. When recording and reproducing are sequentially performed from the inner circumference to the outer circumference or vice versa along the track, there is no problem because the clock marks appear at equal intervals in time.
However, when the light spot performs the access operation across the tracks, the time intervals at which the clock marks appear are scattered, and the PLL is out of synchronization. In the case of the sample servo, since the movement amount, the movement speed, or the track address is detected in the light spot using the clock or timing signal generated by the PLL, the access operation itself becomes impossible.

FIG. 3 shows a segment structure of an embodiment of the optical disc according to the present invention. Similar to FIG. 2, the actual segment length is several tens of μm, but it is enlarged for easy understanding. For servo areas in which servo information such as clock marks, wobble marks, and access codes are preformatted, refer to FIG.
The same arrangement as the sample servo of the CAV method shown in (a) is set and the CAV mode is set. That is, the servo areas are linearly aligned with the disk in the radial direction. Further, the physical length of the servo area is proportional to the radius, and becomes shorter on the inner circumference side of the disk and conversely becomes longer on the outer circumference side. On the other hand, the data area for recording / reproducing data is set to the CLV mode so that the number of data written in the inner circumference is small and the number of data written in the outer circumference is large. The number of data in the data area is increased from 1 byte to several bytes. However, since the increase in circumference is not so large as increasing by 1 byte for each adjacent track, some tracks are set as a group of zones, and the number of data is increased when the zones change. This zone division will be described later. The number of revolutions of the disc shall also be changed for each zone,
In order to keep the linear velocity almost constant, the outer zone is fast and the inner zone is slow. That is, not the complete CLV mode, but the CLV by zone division.
Mode.

Since the servo areas are linearly aligned in the radial direction with respect to the disk, when the access operation is performed in the same zone, the time interval at which the clock marks appear does not change, and as shown in FIG. The problem shown does not occur. When an access operation across zones is performed, the disk rotation speed changes. However, this rotation speed change is due to the spindle motor and the disk having large inertia, and the change in the interval at which the clock marks appear is well within the range of the PLL following ability. That is, when viewed from the PLL, the intervals at which the clock marks appear change substantially continuously. Therefore, there is no problem even if the access operation across zones is performed.

Since the number of rotations becomes slower as it goes to the zone on the outer peripheral side, the time interval in which the servo area appears, that is, the cycle in which the clock mark appears becomes longer. The physical length of the servo area also becomes longer, and the frequency of the servo clock for reading the servo information also decreases accordingly.
On the other hand, the physical length of the data area becomes longer toward the outer circumference side, but the number of data in the data area increases by that amount, and the rotation speed also changes so that the linear velocity is almost constant. The data clock frequency for reading is constant. On the contrary, the data clock is generated with reference to the clock mark in the servo area, but the data clock must have a constant frequency even though the frequency of the clock mark changes depending on the zone. The servo clock and the data clock described here are generated by the servo clock generation circuit 108 and the data clock generation circuit 110 of FIG. 1, respectively. The details of these clock generation circuits will be described later.

FIG. 4 shows an example of the structure of servo data in the servo area of the optical disc of the present invention shown in FIG. As shown previously, the servo area is CAV
It is written in mode, and the physical length becomes longer toward the outer circumference in proportion to the radius. The unique pattern indicates that the clock mark will come next. In the sample servo, detection of a servo signal or recording / reproduction of data is controlled by a clock and timing signal generated by a PLL synchronized with this clock mark. A unique pattern is the first mark for activating the PLL, and it must be detected even if the PLL is not locked. As its name implies, the unique pattern must be a unique one that does not appear anywhere else, and is actually determined by the modulation and demodulation rules. The wobble mark is for obtaining a track shift signal, and is usually composed of a set of two marks which are shifted from the track center in opposite directions. The AF mirror section has no mark or pit because it detects the defocus signal at this portion. The access code is for detecting the moving amount or moving speed of the light spot during the access operation, and a Gray code or the like is used.

FIG. 5 shows an embodiment of the physical sector structure of the optical disk according to the present invention. The physical sector is composed of a header segment in which address information and control information of the physical sector are written and a plurality of data segments in which data can be recorded, reproduced or erased. The data segment is the one shown in FIG. 3, and includes a servo area and a data area. The header segment is
It consists of a servo area, an address area, and a control information area. The servo area is the same as the data segment. In the address area, the track address and sector number where the sector is located are written. Further, in the control information area, the usage status of the sector or the preceding sector, the presence or absence of a defect, the result of verification or the position of a replacement sector in the case of being unusable are written together with the data at the time of recording.

The servo area, address area and control information area in the header segment, and the servo area in the data segment are all written in CAV mode. The information therein is read by the clock and timing signals produced by the servo clock generator circuit 108 of FIG. Servo clock generation circuit 10
As described above, No. 8 is operating at the time of access as well, which enables the access operation. Further, as described above, the data area in the data segment is written in the CLV mode, and the data clock generation circuit 110 in FIG.
Are read out by the clock and timing signals produced by. The servo area in the header segment, the address area, and the servo area in the data segment are pre-formatted at the time of disk creation.

FIG. 6 is a diagram showing the relationship between the physical sectors of the disk shown in FIG. 5 and the logical sectors of data. A logical sector is a minimum unit of a data block when handling data.

FIG. 6A shows a physical sector and a logical sector.
It is an example of correspondence. D is the data to be recorded,
They are arranged in a matrix. C1 is the one in which error correction codes are calculated in the column direction of D, that is, in the horizontal direction, and are arranged in the column direction. C2 is a line in which the error correction codes are calculated in the row direction of D, that is, the vertical direction, and are arranged in the row direction. C2 'is a row in which the error correction code is calculated with respect to C1 and arranged in the row direction. A logical sector is a block of data D to be recorded. A block including the error correction codes C1, C2 and C2 'is assigned to one logical sector in this logical sector, for example, sequentially allocated from the upper left to the lower right of the logical sector to the data area of the data segment in the physical sector. Go

However, since the data amount of the data area in the data segment changes for each zone as described above, it is desirable to change the data amount of the physical sector for each zone in order to effectively utilize it. Then,
Problems arise, such as that the generation rule of the error correction code must be changed for each zone, and that the upper OS and the like must cope with the change in the length of the logical sector.

FIG. 6B shows a physical sector and a logical sector.
It is another example of correspondence. For example, a block of a logical sector n including an error correction code is cut out into one or several bytes, and segments m, m + 1, m + 2
And allocate and distribute to separate data segments. Similarly, the block of the logical sector n + 1 is also cut into 1 byte or several bytes, and segments m, m + 1, m +
Disperse into 2. Even if an integer number of logical sectors are distributed over one track, and the number of bytes to be cut out is combined with the unit of change in the data amount of the data segment when the zone changes, even if the zone changes, one track Only the number of logical sectors of is changed, which is a very simple process.

For example, 16 physical sectors / track, 8
There are 4 data segments / sector and 10 bytes / data segment in a certain zone. In addition, 51 logical sectors
2 bytes and 672 bytes including error correction code.
If the blocks of the logical sector are cut out byte by byte and assigned to the data segment, the data will be distributed over 8 physical sectors, which is exactly half the circumference. In addition, data for 20 logical sectors can be written in one track. The amount of data in the data segment increases by 1 byte in the adjacent zone,
Assuming 11 bytes / data segment, one logical sector is added in the half circumference of the track, and data of 22 logical sectors can be written in one track. By the way, in this state, there are 16 headers in one track, and the number of clock marks in one round is 1360.

FIG. 7 shows an embodiment of zone division, in which a physical sector is cut out in the radial direction.

FIG. 7A shows that the amount of data increase in the data segment for each zone is constant. Since the amount of increase in the circumference is proportional to the amount of increase in the radius, the zones also switch in proportion to the radius, and the number of tracks in the zone becomes constant.

FIG. 7 (b) shows that the linear velocity change range within the zone is constant. The smaller the radius, the greater the change in linear velocity due to the change in radius. Therefore, the smaller the radius, the narrower the zone width.

FIG. 7C shows a case where the amount of data in the zone is constant. Since the data amount of one track increases toward the outer circumference, the zone width becomes narrow.

Oscillation frequencies of the servo clock generation circuit 108 and the data clock generation circuit 110 shown in FIG. 1 will be described with reference to FIG. FIG. 8 shows a segment of an embodiment of the present invention, and is a rewrite of the header segment shown in FIG. 5 or the data segment shown in FIGS. 3 and 5. The lengths of the servo area and the data area are ls and ld, and the number of data bytes in these areas is ns and nd.

The PLL in the clock generation circuit moves in synchronization with the clock mark in the servo area. First, consider the servo clock relationship. The frequency of the byte clock fbs for each byte and the synchronization clock fcms synchronized with the clock mark are expressed as follows.

[0045]

## EQU1 ## fbs = v.ns / ls

[0046]

## EQU2 ## fcms = v / (ls + ld) where v is the linear velocity in the track. Eliminating v from these equations,

[0047]

## EQU00003 ## fcms.multidot. (Ls + ld) .ns = fbs.ls. Since the servo area is written in CAV mode, it has the following relationship.

[0048]

Ls + ld: ls = n: ns The number of bytes when data is written in the entire segment at the byte pitch of the servo area, that is, the total number of data in the segment when the CAV mode is set, and n is an integer. I shall. If we rewrite Equation 3 using this,

[0049]

## EQU00005 ## fbs = fcms.n. The frequency of the recording / reproducing clock, which is the basis for reproducing or recording data, depends on the modulation / demodulation rule. In this embodiment, in order to have a DC-free property,
The 8-10 modulation and demodulation rule is used. This is 1 byte or 8
Add 2 bits to the bit data and set 10 bits to D
Although it has a C-free property, this means that 1-byte data is recorded and reproduced in 10 clocks. When 1 byte of data is recorded / reproduced with the c clock, the reproduction clock frs for servo is given by

[0050]

## EQU6 ## It can be expressed as frs = fbs.c = fcms.n.c. This oscillates frs in the PLL, divides it by c to obtain the byte clock fbs, and further divides the byte clock fbs into n to obtain the synchronous clock fcm.
It shows that s can be made.

Next, the data clock relationship will be considered. The frequency of the clock fbd for each byte and the clock fcmd synchronized with the clock mark are expressed as follows.

[0052]

[Formula 7] fbd = v · nd / ld

[0053]

Fcmd = v / (ls + ld) where v is the linear velocity in the track. Eliminating v from these equations,

[0054]

## EQU9 ## fcmd. (Ls + ld) .nd = fbd.ld. The data area is written in CLV mode, and nd changes for each zone. The ratio of the length of the segment to the length of the data area is defined as follows.

[0055]

Ls + ld: ld = x: y where a and b are mutually prime integers. Using this, if you rewrite equation 9,

[0056]

## EQU11 ## fbd.y = fcmd.x.nd = fosc. However, fosc is the oscillation frequency of the PLL,
It is divided by y to divide the byte clock fbd and fos again.
It is shown that the synchronous clock fcmd can be generated by dividing c by x · nd. However, 1 byte of data is c
When recording / reproducing with a clock, the recording / reproducing clock frwd for data must have the following relationship.

[0057]

[Equation 12] frwd = fbd · c From Equations 11 and 12, y and c are the same, or y is c
It turns out that it is desirable to be a divisor of. If so, fosc = frwd can be set and all necessary clocks can be created from frwd. Otherwise, for example, if y and c are prime, fosc '= fbd
・ Cy must be set, and if fosc 'has a considerably high frequency, the circuit scale of the frequency divider and the like will increase.

Details of the servo clock generation circuit 108 and the data clock generation circuit 110 shown in FIG. 1 will be described based on the above-described frequency relationship.

FIG. 9 shows the servo clock generation circuit 1 of FIG.
08 shows the details of 08. The phase comparator 900 is
A clock mark signal included in the total light amount signal Sa, and a VC
The phase difference with the synchronous clock signal fcms obtained by dividing the frequency of the O (voltage controlled oscillator) 904 is compared, and a voltage proportional to that is generated. The phase difference voltage is phase-compensated by the filter 902 and becomes the drive voltage of the VCO 904. VCO904
Oscillates a reproduction clock frs for servo. Further, the reproduction clock frs is divided into 1 / c by the frequency divider 906 and becomes the byte clock fbs. Further, the byte clock fbs is divided into 1 / n by the frequency divider 908,
It becomes the synchronous clock fcms. In FIG. 9, the portion indicated by the dotted line is the portion which was called the servo PLL before.
This PLL is a feedback loop and works to match the phases of the clock mark signal included in the total light amount signal Sa and the synchronous clock signal fcms. The timing signal generation circuit 910 generates various clocks and timing signals Ts necessary for reproducing the servo signal from the reproduction clock frs, the byte clock fbs, and the synchronous clock fcms. The synchronous clock signal fcms is also sent to the motor control circuit 116.

FIG. 10 shows details of the data clock generation circuit 110 and the zone identification circuit 118 of FIG. However, for c and y described in FIG. 8, c = y
There is. The phase comparator 1000 compares the phase difference between the clock mark signal included in the total light amount signal Sa and the synchronous clock signal fcmd obtained by dividing the VCO (voltage controlled oscillator) 1004, and generates a voltage proportional thereto. The phase difference voltage is phase-compensated by the filter 1002, and VC
It becomes the drive voltage of O1004. The VCO 1004 oscillates a recording / reproducing clock frwd for data. The recording / reproducing clock frwd is 1 / c by the frequency divider 1006.
And becomes the byte clock fbd. The recording / reproducing clock frwd is divided by the frequency divider 1008 into y / (x
The frequency is divided into c) and further divided into 1 / nd by the variable frequency divider 1010 to become the synchronous clock fcmd. The zone identification table 1012 shows the track address Ad.
Identifies the zone number Nz of the track and sends it to the frequency division ratio table 1014. The frequency division ratio table 1014 determines the frequency division ratio nd from the zone number Nz, and the variable frequency divider 10
Send to 10. The zone number Nz is also sent to the motor control circuit. In FIG. 10, the part indicated by the dotted line is the part that was called the data PLL. This PLL is a feedback loop and works to match the phases of the clock mark signal included in the total light amount signal Sa and the synchronous clock signal fcmd. Timing signal generation circuit 10
16 is a reproduction clock frwd and a byte clock fbd
And various clocks and timing signals Td necessary for recording and reproducing the data signal are generated from the synchronization clock fcmd. The synchronous clock signal fcmd is used in the motor control circuit 1
It is also sent to 16.

FIG. 11 shows details of the motor control circuit 116 shown in FIG. The input switch 1100 is
The rotation speed signal Tr from the spindle motor 102 in FIG. 1, the synchronization clock signal fcms from the servo clock generation circuit 108, and the synchronization signal clock signal fcmd from the data clock generation circuit 110 are input and switched. The division ratio table 1102 shows the zone number Nz.
The frequency division ratio nm is determined from and is sent to the variable frequency divider 1104.
The variable frequency divider 1104 divides the signal from the reference frequency oscillator 1106 into 1 / nm and sends it to the phase comparator 1108. The phase comparator 1108 receives this signal and the input selector 11
The phase difference with the signal selected at 00 is compared, and a voltage proportional to that is generated. This phase difference voltage is applied to the filter 11
The phase is compensated at 10, and the spindle motor 102 is driven through the motor drive circuit 1112. Motor drive circuit 1
Reference numeral 112 starts and stops the spindle motor 102 based on a command Sm from the servo control circuit 114.

The motor control circuit of FIG. 11 works so that the frequency obtained by dividing the reference frequency and the rotation speed signal Tr or the synchronous clock signal fcmd or fcmd match.
By changing the frequency division ratio mn of the variable frequency divider 1104 depending on the zone, it is possible to achieve a predetermined rotation speed for each zone.

In the operation of the input switch 1100, first, at the time of start-up, the spindle motor 102 is rotated with reference to the rotation speed signal Tr from the spindle motor 102. When the servo PLL in the servo clock generation circuit 108 is activated, the synchronization clock signal fcms from the PLL is switched to the reference, and thereafter the data clock generation circuit 110 is switched.
When the data PLL therein is activated, it is switched so that the synchronous clock signal fcmd from the PLL is used as a reference. As a result, accurate rotation based on the data PLL can be obtained during recording and reproduction. When accessing another zone, the frequency division ratio in the data PLL changes, so that the synchronization clock fcmd from that point is interrupted or becomes unstable. Therefore, during access, the synchronization clock fcms from the servo PLL is used as a reference, and the mode is restored after the access is completed. Further, when accessing another zone, the frequency division ratio of the frequency divider 1104 changes, and the rotation speed of the spindle motor also changes.

FIG. 12 shows an embodiment related to frequency such as clock or timing signal in the present invention.

Disk diameter is 2.5 inches, diameter is 32 mm
To 62.5 mm, recording and reproduction are performed. 8-10 modulation / demodulation rules, 16 sectors / track,
85 segments / sector including header segment, 1
The amount of data in a segment is 10 bytes in the innermost zone and increases by 2 bytes each time the zone changes. According to the symbols used in this example, x is 6, y is 5, c is 10, n is 12, and nd and nm are 10 to 2.
Increase rapidly.

When the innermost zone is rotated at 4800 rpm, the sampling interval fcm of the synchronous clock, that is, the clock mark is about 108.8 M depending on the zone.
It varies between Hz and 60.4 MHz. However, fc
The sum of ms and fcmd is written as fcm. The original oscillation frequency fr of the servo PLL as the zone changes
Although s changes, the oscillation frequency of the data PLL becomes constant because the division ratio nd changes. Further, the spindle motor control system controls the disk rotation speed for each zone by keeping the reference frequency fm constant and changing the frequency division ratio nm so that the linear velocity becomes substantially constant.

[0067]

According to the optical disk device of the present invention, in the optical disk device using the sample servo, more information can be recorded and the load on the recording / reproducing system can be reduced as compared with the CAV system. In addition, a medium having a small recording power margin can be used.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an embodiment of an optical disk device according to the present invention.

FIG. 2 is an enlarged view of a segment structure of an optical disc.

FIG. 3 is an example of a segment structure of an optical disc according to the present invention.

FIG. 4 is a diagram showing an example of a servo data structure in a servo area according to the present invention.

FIG. 5 is a diagram showing an embodiment of a physical sector configuration of an optical disc according to the present invention.

FIG. 6 is a diagram showing a relationship between a physical sector and a logical sector of an optical disc according to the present invention.

FIG. 7 is a diagram showing an embodiment of zone division of an optical disc according to the present invention.

FIG. 8 is a diagram showing a segment of an optical disc according to the present invention.

FIG. 9 is a diagram showing details of a servo clock generation circuit according to the present invention.

FIG. 10 is a diagram showing details of a data clock generation circuit in the present invention.

FIG. 11 is a diagram showing details of a motor control circuit in the present invention.

FIG. 12 is a diagram showing a relationship between PLL frequencies and the like in the present invention.

[Explanation of symbols]

100 ... Optical disc, 102 ... Spindle motor, 10
4 ... Optical head, 106 ... Signal detection circuit, 108 ... Servo clock generation circuit, 110 ... Data lock generation circuit, 1
12 ... Servo signal detection circuit, 114 ... Servo control circuit,
116 ... Motor control circuit, 118 ... Zone identification circuit, 1
20 ... Data reproduction circuit, 122 ... Error correction circuit, 124
... data recording circuit, 900 ... phase comparator, 902 ... filter, 904 ... VCO, 906 ... frequency divider, 908 ... frequency divider, 910 ... timing signal generation circuit, 1000 ... phase comparator, 1002 ... filter, 1004 ... VCO, 10
06 ... Frequency divider, 1008 ... Frequency divider, 1010 ... Variable frequency divider, 1012 ... Zone identification table, 1014 ... Frequency division ratio table, 1016 ... Timing signal generation circuit, 110
0 ... Input selector, 1102 ... Dividing ratio table, 1104
... Variable frequency divider, 1106 ... Reference frequency oscillator, 1108
... phase comparator, 1110 ... filter, 1112 ... motor drive circuit.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Atsushi Saito Atsushi Saito 1-280, Higashi Koigokubo, Kokubunji, Tokyo Inside the Central Research Laboratory, Hitachi, Ltd. Hitachi Research Laboratory (72) Inventor Tetsuya Fushimi 4026 Kuji Town, Hitachi City, Ibaraki Prefecture Hitachi Research Laboratory, Hitachi, Ltd.

Claims (17)

[Claims] 1. An optical information recording / reproducing system and apparatus having a clock mark for generating a clock at a constant rotation angle on a track on a medium and recording / reproducing information in synchronization with the clock mark. An optical information recording / reproducing method characterized in that a track on a medium is divided into a plurality of zones, and the number of rotations of the medium is changed for each zone. 2. The optical information recording / reproducing method according to claim 1, wherein the number of rotations of the medium is changed based on an interval at which the clock mark appears. 3. The optical information recording / reproducing method according to claim 1, wherein the rotation speed is changed so that the linear velocity of the medium is substantially constant for each zone. 4. A servo clock generating circuit and a data clock generating circuit synchronized with a clock mark on the medium, and reproducing servo information based on a clock and a timing signal from the servo clock generating circuit to generate a data clock. 4. The optical information recording / reproducing method according to claim 1, wherein information recording / reproducing is performed based on a clock and a timing signal from the circuit. 5. The optical information recording according to claim 4, wherein the clock from the servo clock generating circuit generates a clock obtained by dividing a time interval in which the clock mark appears in all zones by a constant number. How to play. 6. The servo clock generating circuit comprises a PLL having a fixed frequency division ratio, and a timing generating circuit for generating a timing for reproducing servo information from a signal of the PLL. Item 5. The optical information recording / reproducing method according to Item 5. 7. A moving amount and a moving speed of the light spot are detected based on a clock and a timing signal from the servo clock generating circuit during an access operation for positioning the light spot on a target track. 5. The optical information recording / reproducing method according to claim 4. 8. The light spot is focused based on a clock and a timing signal from the servo clock generation circuit during an access operation for positioning the light spot on a target track. The optical information recording and reproducing method described. 9. The optical information recording / reproducing method according to claim 4, wherein the clock from said data clock generating circuit has a constant frequency in all zones. 10. The data clock generation circuit comprises a PLL capable of changing a frequency division ratio, and a timing generation circuit for generating a timing for recording / reproducing information from a signal of the PLL, and the PLL according to a zone. 10. The optical information recording / reproducing method according to claim 4, wherein the frequency division ratio is changed. 11. A track on the medium has a servo area containing clock pits and servo information and a data area for recording / reproducing information alternately arranged, and the servo area and the data area are linear in the radial direction of each medium. The optical information recording / reproducing method according to claim 1, wherein the optical information recording / reproducing methods are arranged in a line. 12. The optical information recording / reproducing method according to claim 11, wherein the amount of information in the data area is constant in the zone. 13. The optical information recording / reproducing according to claim 11, wherein the zone is divided so that the length of the data area in the innermost track in the zone increases by a constant length. Method and equipment. 14. A minimum integer ratio of a sum length of the servo area and the data area and a length of the data area is x.
12. The optical information recording / reproducing method according to claim 11, wherein when the number of clocks required for recording or reproducing 1-byte information is c, x is a divisor of c. . 15. The optical information recording / reproducing method according to claim 1, wherein the zone is divided so that the amount of information that can be recorded / reproduced in the zone is constant. 16. The optical information recording / reproducing method according to claim 3, wherein the zone is divided so that the change of the linear velocity in the zone becomes constant. 17. The optical information recording / reproducing method according to claim 1, wherein a phase change medium is used as the medium.