JPH06251380A - Optical recording medium - Google Patents

Abstract

PURPOSE:To make possible efficient recording and retrieval of data from the inner periphery to the outer periphery by splitting the surface of a substrate radially into a plurality of servo zones and setting the number of servo regions per one circle of the servo zone on the outer periphery higher than that on the inner periphery. CONSTITUTION:Surface of the substrate 101 of an optical recording medium 100 is split concentrically into two servo zones 110, 120. The servo zone 110 is further split into two data zones 0, 1 whereas the servo zone 120 is split into six data zones 2-7. The servo regions 102, 103 are provided with fan type clock marks 105 and wobble marks 106, 107 starting from the center 0 of the medium 100. Furthermore, the servo zone 120 is provided with an intermediate servo region 103a between regions 103 along with the clock marks and wobble marks. Consequently, the number of servo regions per one circle of the zone 120 is two times as much as the number of the zones 110 and thereby a substantially constant transfer rate can be sustained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical recording medium for recording information with a focused light beam or reproducing the recorded information, and more specifically, a recording method for the optical recording medium is a sample. Regarding the format.

[0002]

2. Description of the Related Art In recent years, an optical recording medium and a recording / reproducing apparatus for recording on or reproducing from this recording medium are capable of holding and reproducing a large amount of data on the recording medium, and therefore audio information data / video information. Data and various information devices are occupying an important position in the recording and reproduction of data, but there is a strong demand for a larger capacity per recording medium or a smaller recording medium. Improvement is essential.

A conventional physical format of the sample servo system will be described with reference to FIG. In FIG.
1001 is a substrate of the recording medium, for example, 1.2 mm thick
It is made of resin such as polycarbonate, and has a clock mark (also called clock pit) on one surface.
The first wobble mark 10 among the wobble marks 1005a to 1005e and tracking marks (also referred to as tracking pits or wobble marks)
06a to 1006e, second wobble mark 1007
a to 1007e are formed by a method such as injection. This clock mark 1005a to 10
05e and the first wobble marks 1006a to 106
06e, second wobble marks 1007a to 1007
The servo area 1002 formed by e is the recording medium substrate 100.
Radial straight lines emanating from the center O of 1 and alternate long and short dash line 1004
A clock mark 1005 for synchronization is arranged at the intersection with the center line of the spiral or concentric track shown by, and is slightly offset (for example, 1/4 track pitch) on both sides of the track center line before that. Wobble mark 1006a for tracking servo
To 1006e, and second wobble marks 1007a to 1007e. And each servo area 1
Between 002, information areas 1003 are also radially formed. And Te (tellurium) is on the surface.
Recording thin film 10 made of a phase-change recording material containing
09 is formed by a method such as sputtering. In addition, the recording medium includes clock marks 1005a to 1005a.
Zone 0, clock mark 100 up to the inner circumference of 5b
5b to 1005c are immediately divided into zone 1, zone 2 and zone 3 in the same manner, and the information recorded in the information area 1003 of the innermost track in each zone is the recording density or line. It is recorded so that the densities are almost the same.

[0004]

As described above, the conventional recording medium is recorded so that the information density of the innermost track in each zone is almost the same and rotates at a constant rotation speed. (Zone Constant Angular Velocit
The format was designed on the premise of the y, ZCAV method). In the ZCAV method, the information read speed or write speed is the same in the same zone, but the information read speed or write speed is higher in the outer peripheral zone than in the inner peripheral zone, and the so-called data transfer rate depends on the zone. It has the disadvantage that it changes significantly.

In order to solve this drawback, a method of changing the number of rotations of the recording medium according to the zone so that the data transfer rate becomes almost constant (Zone Linear Constant Veloc)
ity, ZCLV method) is known. However, the frequency of the clock mark signal and the wobble mark signal obtained when the recording medium is rotated needs to be a certain frequency or more in order to maintain accurate synchronization or perform highly accurate tracking control. The number of servo areas per round must be a certain number or more.
For example, when the number of revolutions of the recording medium is constant at 1800 rpm, in the conventional recording medium, the number of servo areas per revolution is set to about 1700, and a clock mark signal and a wobble mark signal having a frequency of about 51 kHz are obtained, By this, for example, tracking control in which the gain intersection is around 3 kHz was constructed.

However, the conventional recording medium is changed to ZCLV.
When used in a system, the following drawbacks occur.
For example, the diameter of the recording medium is 120 mm, the zone 0 is 40 to 59 mm in diameter, and the zone 1 is 59 to 78 m in diameter.
m, the zone 2 has a diameter of 78 to 97 mm, the zone 3 has a diameter of 97 to 116 mm, and the rotation speed of the recording medium in the outermost zone 3 is 900 rpm, the rotation speed in the innermost zone 0 is about 2183 rpm. Therefore, in order to obtain the clock mark signal and the wobble mark signal having the frequency of about 51 kHz in the zone 3, the number of servo areas per one round needs to be about 3,400, which is twice the conventional number. When a large number of servo areas are provided in this way, the area of the information area becomes small and the information capacity that can be stored becomes small.

Further, regarding the interval between the clock mark 1105a and the second wobble mark 1107a in the innermost zone 0, or the interval between the first wobble mark 1106a and the second wobble mark 1107a, desired information is obtained from each mark. Therefore, it requires a certain distance equal to or higher than the resolution of the light spot. If the mark intervals on the innermost track are the minimum distances required to obtain this resolution, the mark intervals on the tracks of the servo area 1102 radially extending from the center become wider in proportion to the radius of the recording medium. The perimeter is much wider than necessary. Further, as the information track is provided up to a smaller radius, the surface area of the recording medium used becomes larger, but the area occupied by the servo area also becomes relatively large.

As described above, when the conventional optical recording medium is used in the ZCLV system, it is necessary to increase the number of servo areas per one turn, and when a recording zone is provided up to the inner circumference, the servo area of the innermost circumference is required. Since there is a need to maintain the pit interval in, the area ratio occupied by the servo area becomes large and the storage capacity becomes small. The present invention solves such problems in the conventional optical recording medium,
(EN) An optical recording medium that can be used in the CLV system, reduces the area ratio occupied by a servo area, can efficiently record data from the inner circumference to the outer circumference, and is suitable for instantly searching for desired information. With the goal.

[0009]

In order to achieve this object, the optical recording medium of the present invention constitutes one servo area with a clock mark for synchronization, a first wobble mark and a second wobble mark. , A plurality of these servo areas are arranged on a spiral or concentric circular track intermittently and at equal intervals per revolution, and clock marks are arranged on the track center line and on a straight line radiating with respect to the disk center. The first and second wobble marks are equidistant from each other with respect to the track center line in the outer peripheral direction and the inner peripheral direction, are provided in front of or behind the clock mark in the track direction, and are radial with respect to the disc center. In an optical recording medium arranged so as to be located on a straight line, it is divided into at least two servo zones in the radial direction, and servos per revolution in the outer servo zones are performed. Those with more than the number of servo areas per round in the inner circumference of the servo zones and the number of frequency.

[0010]

The optical recording medium of the present invention has the above-mentioned structure.
Since the number of servo areas per revolution in the outer servo zone is larger than the number of servo areas per revolution in the inner servo zone, the rotation speed of the inner circumference is higher than that of the outer circumference of the optical recording medium, and It is possible to easily realize the recording and reproducing of the ZCLV method in which the transfer rate of 1 is almost constant without reducing the capacity.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An optical recording medium according to an embodiment of the present invention and an optical recording / reproducing apparatus suitable for using this optical recording medium will be described below with reference to the drawings. FIG. 1 shows a partial plan view of an optical recording medium according to a first embodiment of the present invention which is suitable for use in the ZCLV system. In FIG. 1, a substrate 101 of an optical recording medium 100 is formed of a resin such as polycarbonate having a thickness of 1.2 mm, and clock marks (also referred to as clock pits) 105a to 105i on one surface, and a first Wobble marks (also referred to as tracking marks or tracking pits) 106a to 106i, second wobble mark 10
7a to 107i are formed by a technique such as injection. The alternate long and short dash line 104 indicates the center of each concentric or spiral track, and the clock marks 105a to 105i for clock reading are arranged on the alternate long and short dash line 104, and the track centers are spaced before and after the clock marks 105a to 105i. The first wobble marks 106a to 106i and the second wobble marks 107a to 107i for tracking servo are provided on both sides of the line by slightly deviating from each other (for example, by 1/4 track pitch). On the surface of the substrate 101, a recording thin film 109 made of, for example, a phase change recording material containing Te (tellurium) as a main component is formed by a method such as sputtering.

The surface of the substrate 101 of the optical recording medium 100 is concentrically divided into two servo zones, a first servo zone and a second servo zone. Further, the first servo zone is divided into two data zones, zone 0 and zone 1, and the second servo zone is divided into six data zones, zone 2 to zone 7. Clock mark 10
5a to 105h, first wobble marks 106a to 106h, second wobble marks 107a to 107
The symbol h indicates that on the innermost track in zones 0 to 7, and the clock mark 105i, the first wobble mark 106i, and the second wobble mark 107i indicate those on the outermost track in zone 7. Therefore, the clock marks 105a and 105b, the first wobble marks 106a and 106b, and the second wobble mark 1
07a and 107b are within the range of the first servo zone 110, and the servo area 102 of the first servo zone 110 formed of these is formed so as to be radially fan-shaped from the center O of the optical recording medium 100. Also clock mark 1
05c to 105i, first wobble marks 106c to 106i, second wobble marks 107c to 10
7i is within the range of the second servo zone 120, and the servo area 103 of the second servo zone 120 formed of these is also formed so as to be radially fan-shaped from the center O of the optical recording medium 100.

In the second servo zone 120, the second
An intermediate servo area 103a is provided between the servo area 103 of the servo zone and the servo area 103 of the next second servo zone.
Is provided. In the intermediate servo area 103a, the clock mark, the first wobble mark, and the second wobble mark are arranged similarly to the servo area 103 of the second servo zone. That is, the servo area 1 of the second servo zone
Clock marks 105c to 105i similar to
First wobble marks 106c to 106i and second wobble marks 107c to 107i are provided.
Therefore, the number of servo areas per revolution in the second servo zone is twice that in the first servo zone.

In one fan-shaped servo area, the clock mark 10 in the servo area 102 of the first servo zone.
5a, 105b and the servo area 103 of the second servo zone
The clock marks 105c to 105i are formed on the same straight line passing through the center O of the optical recording medium 100. Similarly, the intermediate servo area 103 of the second servo zone
The clock marks 105c to 105i in a are also formed on the same straight line passing through the center O of the optical recording medium 100. Further, the clock marks 105 on one circumferential track are arranged at equal angles with respect to the center O of the optical recording medium 100. That is, the clock marks 105 on one circular track are arranged at equal intervals.

The first wobble mark 106c and the clock mark 105c, and the clock mark 105c and the second wobble mark 107c have the same interval and are equal to or higher than the resolution of the light spot and are the minimum suitable for obtaining desired information from each mark. It is formed to have a space. Also, the first
The straight line connecting the wobble marks 106a and 106b and the second line
The central angle formed by the straight line connecting the wobble marks 107a and 107b with respect to the center O of the optical recording medium 100 is the straight line connecting the first wobble marks 106c and 106i and the straight line connecting the second wobble marks 107c and 107i. The recording medium 100 is formed so as to have a center angle twice the center O of the recording medium 100.

Information such as address numbers or data is recorded between servo areas. Therefore, the information area 108a of the first servo zone and the information area 108b of the second servo zone are also fan-shaped radially from the center O of the optical recording medium 100, but since the servo areas are formed as described above, Servo zone or second
The central angle of the information area 108b of the servo zone is 1/2 of the central angle of the information zone 108a of the inner servo zone, that is, the first servo zone. As described above, the data zone is divided into eight zones, that is, zone 0 to zone 7, but the bit length of the data on the innermost track in each data zone is almost equal, and the radius within the same data zone is the same. It is recorded so that it becomes longer in proportion to. That is, assuming that the recording medium 100 is rotated at a constant number of revolutions, the reading speed of the data reproduced from the recording medium 100 is constant within the same data zone, but the outer peripheral data zone becomes faster. It is recorded.

FIG. 2 is an enlarged view of the boundary portion between the zones 1 and 2 on the surface of the optical recording medium 100 of FIG. 1, that is, the boundary portion between the first servo zone 110 and the second servo zone 120. The distance between each mark in zone 1 is twice as large as that in zone 2.
The number of servo areas is twice that in zone 1.

FIG. 3 conceptually shows the format on the optical recording medium 100 and is a drawing for explaining how data is arranged. As shown in FIG. 3A, a track on the optical recording medium 100 is formed by alternately arranging servo areas and information areas, and a pair of servo areas and information areas form one block. There is. Then, as shown in FIG. 3B, one sector is (n +
1) The information area of a block at the head of a sector is an address area in which an address (for example, a track number and a sector number) for identifying the position of the sector is recorded. And the following n
Data is recorded in the information area of each block. This address does not necessarily have to be provided at one location for each sector as shown in the figure. For example, one location can be provided for one circumferential track, that is, one track, and the target sector can be accessed by counting the number of blocks based on that location. Is. Next, as shown in FIG. 3C, one track in a certain zone is composed of m sectors, and when one track cannot be divided by one sector length, a surplus area is provided at the end of the track.

FIG. 4 shows an address area on the optical recording medium 100. One information area is assigned as the address area of the second servo zone, and the address is the optical recording medium 1.
It is pre-recorded in the form of concave and convex pits so as to form a fan shape from the center O of 00. That is, the information bit length (1 bit physical length) of the address signal is recorded so as to be long in proportion to the radius. In other words, the address recorded in the address area in the second servo zone is
When the optical recording medium 100 is rotated at a constant rotation speed, the data is recorded so that the data transfer rate of the address signal becomes constant. Also, one information area is assigned as the address area of the first servo zone, and the address is prerecorded in the form of concave and convex pits so as to form a fan shape from the center O of the optical recording medium 100, as in the second servo zone. However, the central angle formed by the address area of the first servo zone with respect to the center O of the optical recording medium 100 is twice the central angle formed by the address area of the second servo zone with respect to the center O of the optical recording medium 100. Is provided. In other words, if the optical recording medium 100 is rotated at a constant rotation speed, the data transfer rate of the address signal recorded in the address area in the first servo zone is recorded in the address area in the second servo zone. 1/2 of data transfer rate of address signal
It is recorded so that.

As described above, since the data area is formed radially, the same servo zone becomes wider toward the outer circumference of the recording medium, and the data amount is the same in the same data zone (not the servo zone). However, it is possible to record so that the data amount per one information area increases in the outer data zone. Further, as shown in FIG. 1, in the optical recording medium of the present invention, the central angle of the servo area can be made narrower in the outer servo zone. The inner servo zone has a wider servo area, but since the number of servo areas can be halved compared to the outer servo zone, the recording efficiency of the information area is improved.

For this reason, in the present embodiment, the servo zones are divided in the radial direction of the recording medium, and in the same servo zone, the outermost data zone has a larger amount of data recorded in one data area. To increase capacity. That is, the data is recorded so that the spatial frequencies of the data pits in the data area in the innermost track of each data zone are substantially equal.

The diameter of the optical recording medium is set to 120 mm, and the optical recording medium 100 is set so that the data transfer rates are almost equal.
Table 1 shows specific numerical examples of the data zone area, the number of rotations of the motor for rotating the optical recording medium 100, and the clock mark (CK mark) frequency when the disk is rotated.

[0023]

[Table 1]

As shown in Table 1, in the same servo zone, the CK mark frequency becomes lower in the outer data zone, and inevitably the wobble mark frequency also becomes lower.
A timing clock is generated by multiplying the CK mark, and the position detection of the wobble mark, address reading, or reading of data recorded in the data area is performed based on this timing clock. Therefore, in order to generate an accurate timing clock, the CK mark needs to have a predetermined frequency or higher. Further, as described above, the track shift signal is obtained from the pair of wobble marks, but the frequency of the wobble mark needs to be equal to or higher than a predetermined value in order to perform highly accurate tracking control based on the track shift signal. . In the optical recording medium 100 of FIG. 1, the CK mark frequency and the wobble mark frequency are equal, and when the optical recording medium 100 is rotated as shown in Table 1, both mark frequencies become 53.8 kHz or higher.

The data amount per sector is generally constant, for example, 1024 bytes. However, since the amount of data per rotation of the recording medium differs depending on the zone, the number of sectors per rotation also differs depending on the zone.
Therefore, the number of addresses inevitably differs depending on the zone. However, since an address mark that can identify the address position is also recorded at each address, it is possible to instantaneously read based on this address mark.
Further, since the addresses are provided radially in the same servo zone, they can be easily read by generating a timing clock corresponding to the rotational position of the optical recording medium 100 by multiplying it by the CK mark.

The method of providing the address information does not have to be limited to the above embodiment. For example, in order to improve the reliability of address reading, a plurality of address area blocks may be provided. For example, address 1 and address 2 having the same number may be recorded in one block, and two blocks may be used as the address area. Also, one address information may be provided over a plurality of blocks, or a plurality of address information may be provided for one block.

Next, an optical reproducing apparatus suitable for reproducing a signal by changing the number of rotations of the optical recording medium 100 according to the data zone, FIG. 5 which is a block diagram thereof, and signal waveforms of respective parts thereof are shown. A description will be given in combination with FIG. 7. Figure 5
In FIG. 1, the phase change type optical recording medium 100 shown in FIG. 1 is attached to the rotary shaft 502 of the motor 501. Then, the motor 501 is controlled by the motor control circuit 523 so as to rotate at a predetermined rotation speed corresponding to each zone.

Inside the transfer table 504, for example, a light source 505 such as a semiconductor laser, a coupling lens 506, a polarization beam splitter 507, a quarter wave plate 508, a total reflection mirror 509, a photodetector 511 and an actuator. The fixed part 512 (not shown) is attached to the transfer table 50.
4 is configured to move in the radial direction of the optical recording medium 100 by a transfer motor 503 such as a linear motor.

An optical beam generated by a light source 505 such as a semiconductor laser disposed in the transfer table 504 is collimated by a coupling lens 506, and then polarized beam splitters 507, 1/4. After passing through the wave plate 508, the total reflection mirror 5
And the optical recording medium 1 is reflected by the focusing lens 510.
The recording surface of No. 00 is focused and irradiated. Optical recording medium 10
The reflected light reflected by the recording surface of 0 is the focusing lens 51.
After passing through 0, it is reflected by the total reflection mirror 509, after passing through the ¼ wavelength plate 508, is reflected by the polarization beam splitter 507, and is irradiated onto the photodetector 511. Focusing lens 5
Reference numeral 10 is attached to a movable portion of the actuator 512. The actuator 512 is composed of a tracking coil 513 provided in the movable part and a permanent magnet (not shown) attached to the fixed part. Therefore, when a current is passed through the tracking coil 513, the focusing lens 510 is moved in the radial direction of the optical recording medium 100, that is, across the track on the optical recording medium 100 by the electromagnetic force received by the coil from the permanent magnet (FIG. Move to the left and right). Also, the actuator 512
A focusing coil (not shown) is also attached to the movable part of the focusing lens 510 of the optical recording medium 100 by an electromagnetic force received by the coil from a permanent magnet (not shown) when a current is passed through the coil. The focusing lens 510 is configured to be movable in a direction perpendicular to the plane, and the focusing lens 510 is focus-controlled so that the optical beam irradiated on the optical recording medium 100 is always in a predetermined focusing state.

FIG. 7A is a diagram schematically showing the arrangement of marks (pits) on the recording medium. The first and second wobble marks are located above and below the center line (dotted line). They are arranged offset. When a pit on the disc as shown in FIG. 7A is detected, the output of the photodetector 511 is input to an I / V converter 514 that converts a current into a voltage, and the output from the I / V converter 514 shown in FIG. ) Is output. One of the output signals is input to the tracking error detector 515, and the tracking error detector 515 detects the positional deviation between the light beam spot and the track based on the amplitude difference between the first and second wobble marks. That is, the tracking error detector 515 outputs the first signal from the output signal of the I / V converter 514.
Then, the peak value of the second tracking (wobble) mark signal is detected, and the signal indicating the positional deviation between the track on the optical recording medium 100 and the light beam, that is, the tracking error signal is obtained from the difference between the peak values. Then, this tracking error signal is applied to the actuator 512 via the control circuit 516 so that the light beam on the optical recording medium 100 is positioned between the first and second wobble marks, that is, on the center line 104 of the track. Tracking control. In addition, the transfer table 504 is applied from the control circuit 516 to the transfer motor 503, and the transfer table 504 is transferred and controlled so that the focusing lens 510 moves in the radial direction of the recording medium around the natural state.

The output signal of the I / V converter 514 is a clock (CK) mark detection circuit 517 and a binarization circuit 51.
It is entered in 8. The binarization circuit 518 binarizes the output signal of the I / V converter 514 as shown in FIG. C
The binarized signal of the binarization circuit 518 and the output signal of the I / V converter 514 are input to the K mark detection circuit 517. The CK mark detection circuit 517 detects the position of the clock mark and differentiates the clock mark signal to output the sync signal FIG. 7D corresponding to the clock mark. The timing clock generation circuit 519 is a circuit that generates various signals in synchronization with the synchronization signal of the CK mark detection circuit 517 as described later, and generates a period signal indicating each position of the wobble mark to generate the tracking error detector 515. To the address read circuit 520 for generating a timing clock for address reading.
Send to. Further, the timing clock generation circuit 519 generates a timing clock for reading data and sends it to the data reading circuit 522.

The address reading circuit 520 includes a binarized signal from the binarizing circuit 518 and the timing clock generating circuit 5.
A timing clock for address reading from 19 is input. The address reading circuit 520 determines whether the binarized signal is 1 or 0 based on this timing clock, reads the address on the recording medium, and sends the read address to the control circuit 521. The circuit that generates the timing clock for reading the data in the timing clock generation circuit 519 is the control circuit 5
The timing clock adapted to each zone of the recording medium is generated according to the instruction 21. The control circuit 521 controls the timing clock generation circuit 519 based on the address read by the address reading circuit 520 to generate the timing clock for data reading corresponding to the zone corresponding to the address position. The timing clock for reading this data is sent to the data reading circuit 522. The binarization signal from the binarization circuit 518 is also input to the data reading circuit 522, and the data reading circuit 523 determines the timing clock generating circuit 5
Based on the data reading clock signal from 19, the binary signal is judged and the information recorded on the optical recording medium 100 is read. Further, the motor control circuit 523 is configured so that the rotation speed of the motor 501 can be changed according to an instruction from the control circuit 521.

The timing clock generation circuit 519 of FIG.
Will be described with reference to FIG. 6, which is a block diagram of the main part thereof. The timing clock generation circuit 519 has two timing generation means, that is, a PLL (phase locked loo).
p) 610 and 620 are provided. A PLL 610, which is a first timing clock generating means, generates a timing clock for reading an address and detecting the positions of the first and second wobble marks, and includes a phase comparison circuit 611 and a VCO (voltage controlled ocsilator).
612, a 1/2 frequency divider 613 and a frequency divider 614. The PLL 620, which is the second timing clock generation means, generates a timing clock for reading the data recorded in the data area on the optical recording medium, and includes the phase comparison circuit 621 and the VCO 622.
And a frequency divider 623.

First, the operation of the PLL 610 will be described. The VCO 612 generates a signal having a frequency corresponding to the input signal, and the ½ frequency divider 613 serves as the VCO 61.
The frequency of the output signal of 2 is divided into 1/2, and the frequency divider 614
Selects the frequency of the output signal of the VCO 612 or the output signal of the 1/2 frequency divider 613 by switching the switch 615, divides it by an integer, and sends this divided signal to the phase comparison circuit 611. . The phase comparison circuit 611 compares the phase of the sync signal corresponding to the clock mark detected by the CK mark detection circuit 517 and the phase of the signal frequency-divided by the frequency divider 614, and outputs a phase difference signal corresponding to the phase difference between both signals. VCO6
Send to 12. Therefore, the VCO 612 synchronizes the synchronization signal from the CK mark detection circuit 617 with the signal divided by the frequency divider 614, or the synchronization signal from the CK mark detection circuit 617 and the 1/2 frequency divider 613. Frequency divider 6
The signals divided by both 14 are controlled so as to be synchronized with each other, for example, the phases of both signals are matched. For example, if the frequency division ratio of the frequency divider 614 is 1/200,
Assuming that the 12 signals are input to the frequency divider 614 via the switch 615, the oscillation frequency of the VCO 612 is a frequency diagram 7 (f) that is 200 times the clock mark frequency of the clock mark detector 517. (Here, for simplification, the frequency is shown as 17 times the clock mark frequency).

The counting circuit 616 is configured to count the output signal of the switch 615 and reset it with the output signal of the frequency divider 614 shown in FIG. 7 (e). Since the signal of the clock mark detector 517 and the signal of the frequency divider 614 are synchronized, the count value of the counting circuit 616 is the clock mark detector 5
17 shows the time corresponding to the time from the clock mark detected in 17, that is, the rotation angle of the recording medium. The decoder 617 includes two bit comparators, one bit comparator detects that the count value of the counting circuit 616 exceeds a predetermined value, and the other bit comparators detect that the count value of the counting circuit 616 is less than or equal to the predetermined value. Detect that there is. Then, it is detected from the logical product of both bit comparators that the count value of the counting circuit 616 is in a predetermined range, that is, a period corresponding to the information area, and a high level signal FIG. 7 (i) is sent to the AND circuit 619 during this period. . Therefore, from the AND circuit 619 to the address reading circuit 520
The clock signal sent to is a clock signal for reading the address of the area of the recording medium at that time. Decoders 618a and 618b detect the first and second wobble mark detection positions, and the period signal of each wobble mark is shown in FIG.
(G) and FIG. 7 (h) show the tracking error detector 5
Send to 15. The tracking error detector 515 detects the peak value of each wobble mark signal output during the period in which the period signal is output, and detects the track shift signal by obtaining the difference between the two peak values. The decoders 618a and 618b forming the period signal generating means are each composed of two bit comparators like the decoder 617. The respective comparison values of the two bit comparators are set to predetermined values. In addition, the wobble mark is configured to output a signal for a predetermined period.

As described above, in this embodiment, the number of servo areas in the second servo zone is twice the number of servo areas in the first servo zone, and the radiation angle of the servo area in the second servo zone (optical recording The central angle formed with the center O of the medium 100) is 1/2 of the radiation angle of the servo area in the first servo zone. Therefore, the second
It is necessary to double the frequency of the timing clock for address reading or wobble mark position detection in the servo zone to that in the first servo zone. Therefore, the control circuit 521 determines the servo zone based on the address, and switches the switch 615 so that the clock frequency of the output signal of the switch 615 is double in the second servo zone with respect to the first servo zone. Since the frequency of the CK mark signal from the CK mark detection circuit 517 in the second servo zone is twice that in the first servo zone, for example, assuming that the optical recording medium 100 is rotating at a constant rotation speed, Switch 6
VCO6 in the first servo zone by switching 15
The oscillation frequency of 12 and that in the second servo zone are the same. That is, if the servo zones are switched properly, the time required for pulling in the PLL 610 can be eliminated, and therefore, even if the servo zones are crossed, there is no problem in address reading or wobble mark position detection. .

Unlike the PLL 610, the PLL 620 does not switch the frequency divider, and the frequency divider 623 is constructed so that the frequency division ratio can be changed by the control circuit 521. Therefore, the CK from the CK mark detection circuit 517
In order to synchronize the mark signal and the signal of the frequency divider 623, VC
Although the O 622 is controlled, the frequency of the output signal of the VCO 622 corresponds to the frequency division ratio set by the control circuit 521. The counting circuit 626 counts the output signal of the VCO 622 and is reset by the output signal of the frequency divider 623. The decoder 627 is composed of two bit comparators whose comparison values can be set. The control circuit 521 determines the zone to which the track being reproduced belongs based on the address read by the address reading circuit 520 to determine the division ratio of the frequency divider 623 and the decoder 627.
Set the comparison value of the two bit comparators. Therefore, the VCO 622 outputs a timing clock having a frequency suitable for the data zone being reproduced, and the decoder 627 outputs a predetermined data reading period signal.

The operation of the optical reproducing apparatus shown in FIG. 5 for continuously reading data over a plurality of zones in the above structure will be described with reference to FIG. As shown in FIG.
While reproducing zone 0, the motor 501 is rotating at a predetermined speed adapted to zone 0, for example, 2396 rpm. Then, when the zone 0 is switched to the zone 1, the control circuit 521 identifies the track where the light beam is located based on the address read by the address reading circuit 520, detects the boundary of the zone, and conforms to the zone 1. The rotation speed command information is sent to the motor control circuit 523 so that the motor 501 rotates at a speed, and the motor 501 gradually decelerates to a rotation speed suitable for zone 1, for example, 1936 rpm. The switch 615 is in the state shown in FIG. 6 while reproducing zone 0 and zone 1 in the first servo zone. Depending on the rotation speed of the motor 501, the detection output of the CK mark detection circuit 517 changes from 66.6 kHz to 5
Although it decreases to 3.8 kHz, since the PLL 610 operates so that the phase of the output signal of the frequency divider 614 matches the phase of the output signal of the CK mark detection circuit 517, while the motor 501 is decelerating. Also in the decoder 618
a and 618b output a signal for a predetermined period, and the AND circuit 6
An address can be read at all times with a clock signal from 19. Further, when entering the zone 1, the control circuit 521 sets the frequency division ratio of the frequency divider 623 and the comparison value of the bit comparator in the decoder 627 so as to match the zone 1. Since the motor 501 gradually decelerates, the data transfer rate is higher than a predetermined value at the moment of switching from zone 0 to zone 1, for example, 12.4M.
bps, which decreases with deceleration of the motor 501 and reaches a predetermined data transfer rate, for example 10.0 Mbps. Therefore, the data read clock output from the AND circuit 629 becomes a data read clock suitable for the zone to which the track where the light beam is located belongs, and the data read circuit 522 outputs the data read clock of the binarization circuit 518 based on this clock. Data is read by determining whether the binary signal is 1 or 0.

Next, when switching from zone 1 of the first servo zone to zone 2 of the second servo zone, the control circuit 521 identifies the track on which the light beam is located based on the address read by the address reading circuit 520. Then, the boundary of the zone is detected, and the servo zone switching signal is changed from low to high as shown in FIG. 8D, and the switch 615 is connected to the opposite side of FIG. Further, the control circuit 521 sends the rotation speed command information to the motor control circuit 523 so that the motor 501 rotates at the speed adapted to the zone 2, and the motor 501 gradually decelerates to the rotation speed adapted to the zone 2, for example, 1625 rpm. It becomes the rotation of. When the switch 615 is switched, the frequency divider 61
The output signal of No. 4 instantly doubles in frequency, but the frequency of the CK mark signal from the CK mark detection circuit 517 is also shown in FIG.
As shown in (e), for example, from 53.8 kHz, it doubles to 107.6 kHz instantaneously, and it decreases to 90.3 kHz according to the speed of the motor, so that the PLL 610 operates without any problem. Therefore, even while the motor 501 is decelerating, the decoders 618a and 618b output signals for a predetermined period, and the clock signal from the AND circuit 619 can always read the address. Further, when entering the zone 2, the control circuit 521 sets the frequency division ratio of the frequency divider 623 and the comparison value of the bit comparator in the decoder 627 so as to match the zone 2. Since the speed of the motor 501 does not change instantaneously and gradually decreases, the data transfer rate is higher than a predetermined value at the moment of switching from zone 1 to zone 11.9M.
bps, and decreases as the motor 501 decelerates to 1
It will be 0.0 Mbps. Therefore, the AND circuit 629
The data read clock output by the data read circuit 522 is a data read clock adapted to the zone to which the track in which the light beam is located belongs.
Can read data.

As described above, the central angle of the servo area in the outer servo zone with respect to the disk center is set to 1/2 of the central angle with respect to the disk center in the inner servo zone, and the number of servo areas per revolution in the outer servo zone is calculated. Although the embodiment in which it is twice as large as that in the inner servo zone has been described, the ratio of the central angle to the disk center in the outer servo zone and the central angle to the disk center in the inner servo zone can be set arbitrarily. .

That is, in the embodiment of the optical recording medium of FIG. 1, the straight line connecting the first wobble marks 106a and 106b and the straight line connecting the second wobble marks 107a and 107b are to the center O of the optical recording medium 100. The central angle of the eggplant is
The straight line connecting the first wobble marks 106c and 106i and the straight line connecting the second wobble marks 107c and 107i are formed to be twice the central angle formed with respect to the center O of the optical recording medium 100. The ratio does not necessarily have to be 2.

For example, the radius of the innermost track in the inner servo zone is R0 and the radius of the innermost track in the outer servo zone is R1, and the first wobble of the innermost track in the inner servo zone is set. The distance between the mark and the clock mark, the distance between the clock mark and the second wobble mark, the distance between the innermost first wobble mark and the clock mark in the outer servo zone, and the distance between the clock mark and the second wobble mark are the same. If the distance is greater than the resolution of the light spot and is the minimum distance suitable for obtaining the desired information from each mark, the central angle of the servo area in the inner servo zone is the servo angle in the outer servo zone. R of the central angle of the area
It becomes 1 / R0 times.

As an example of an optical reproducing apparatus suitable for reproducing such an optical recording medium, FIG. 9 shows a block diagram of its main part.
FIG. 9 shows the timing clock generation circuit 519 in FIG.
Is partially changed to 519a, and parts having the same functions as those in FIG. 6 are denoted by the same reference numerals and detailed description thereof will be omitted. Figure 9
In the PLL 700, the phase comparison circuit 701, the VCO 7
02, a frequency divider 703, a PLL 710 including a phase comparison circuit 711, a VCO 712, and a frequency divider 713. The circuit 721 of the switch 720 selects the output of the VCO 702 or 712 and adds it to the counting circuit 616. The output of the frequency divider 713 or the frequency divider 703 is selected by the circuit 722 of 720 and is used as the reset input of the counting circuit 616. Then, for example, set the PLL 710 to a value adapted to the first servo zone on the inner circumference, and
If 700 is set to a value suitable for the second servo zone on the outer circumference, and the switch 720 is switched by the servo zone switching signal of the control circuit 521, the ratio between the center angles of the inner and outer servo zones can be freely set. It is possible.

Although the respective embodiments of the present invention have been described above, the present invention is not limited to the embodiments. Although the present invention has been illustrated by dividing the servo zone into two servo zones in the embodiment, the servo zone may be divided into a plurality of servo zones of three or more, and the outer peripheral servo zones may be increased in the number of servo areas per revolution. .

In the embodiment, the number of servo areas in the outer servo zone is 1: 2 with respect to the inner servo zone.
However, this ratio may be set appropriately. In that case, at least one servo area per one turn is configured to radiate from the center of the disk, and the address area is provided immediately after the servo area. It is convenient for soup stock. Further, when divided into a plurality of servo zones, if the central angle of the servo area with respect to the disk center is made smaller in the outer servo zone, the information area is increased, so that the recording capacity can be increased.

Generally, the clock mark and the first,
The interval between the second wobble marks is set to an integral multiple of the minimum address mark interval, and the second wobble marks are arranged so that the timing clock can also be used. However, the interval between the clock mark and the first and second wobble marks may be set so as not to cause intersymbol interference in the reproduction signal of the clock mark, and the minimum interval satisfying this condition may increase the density. However, it is not necessarily required to be an integral multiple of the shortest address mark interval. In this case, if the timing clock for address reading is also used, the frequency becomes high, and the circuit becomes complicated and expensive. Therefore, the timing clock for detecting the position of the wobble mark and the timing clock for reading the address may be separately provided.

The arrangement of the wobble mark and the clock mark is not limited to the example, and even if the front and rear are interchanged,
Of course, if the circuit is adapted to it, it can be used similarly.

Further, it is not always necessary to provide one address area for each sector. If at least one address area is provided for one track, the necessary sectors can be reached by counting the number of data areas. . Further, in the present invention, it goes without saying that the tracks are not limited to the spiral shape and may be concentric shapes.

Further, it is naturally used not only in a recordable / reproducible optical recording medium but also in a read-only optical recording medium having a reflective film such as aluminum, and in the recordable medium, a phase change type recording medium, It does not matter whether it is a magneto-optical recording medium or not.

[0050]

As described above, the optical recording medium of the present invention is divided into a plurality of servo zones in the radial direction, and the inner servo zone has a servo area per turn that is larger than that of the outer servo zone. Since the number is small, the ZCLV recording or reproducing in which the rotation speed of the optical recording medium at the outer circumference is made smaller than that at the inner circumference to make the data transfer speed substantially constant can be easily realized.

Further, if the central angle of the servo area in the outer servo zone with respect to the disk center is smaller than the central angle of the servo area in the inner servo zone with respect to the disk center, the information area can be increased, so that the optical recording can be performed. The data storage capacity of the entire medium can be increased.

[Brief description of drawings]

FIG. 1 is a plan view of an essential part of an optical recording medium according to an embodiment of the present invention.

FIG. 2 is a conceptual diagram of comparison of recording data arrays near the zone boundaries on the recording medium.

FIG. 3 is a conceptual diagram of a data array on the recording medium.

FIG. 4 is a plan view of an essential part showing an address area on the recording medium.

FIG. 5 is a block diagram of an optical reproducing device which is also suitable for reproducing the recording medium.

FIG. 6 is a block diagram of a timing clock generation circuit of the same main part.

FIG. 7 is a schematic diagram of data on the optical recording medium of the present invention and an operation waveform diagram of each circuit portion during reproduction.

FIG. 8 is a conceptual diagram of the operation of each part when straddling a plurality of servo zones on the optical recording medium.

FIG. 9 is a block diagram of another example of the timing clock generation circuit of the optical reproducing apparatus which also reproduces the optical recording medium.

FIG. 10 is a plan view of a main portion of a conventional optical recording medium.

[Explanation of symbols]

 100 Optical Recording Medium 101 Optical Recording Medium Substrate 102 First Servo Zone Servo Area 103 Second Servo Zone Servo Area 103a Second Servo Zone Intermediate Servo Area 104 Track Center Line 105a-i Clock Mark 106a-i First Wobble Mark 107a-i 2nd wobble mark 108a Information area of 1st servo zone 108b Information area of 2nd servo zone 109 Recording thin film 501 Motor 511 Photodetector 514 I / V converter 515 Tracking error detector 517 CK mark detection circuit 518 2 Value conversion circuit 519 Timing clock generation circuit 520 Address reading circuit 521 Control circuit 522 Data reading circuit 523 Motor control circuit 610,620 PLL 611,621 Phase comparison circuit 612,622 VC 613 1/2 frequency divider 614,623 divider 616,626 counting circuit 617,618a, 618b, 627 decoder 619,629 the AND circuit

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Shinichi Kadowaki 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (6)

[Claims] 1. A servo area is composed of a clock mark for synchronization, a first wobble mark, and a second wobble mark, and a plurality of servo areas are intermittently formed on a spiral or concentric track per revolution. And the clock marks are arranged at equal intervals on a track center line and on a straight line radiating with respect to the center of the disk, and the first and second wobble marks are equidistant from each other with respect to the track center line. Information is provided between the servo areas so as to be separated from the outer circumferential direction and the inner circumferential direction, provided in front of or behind the clock mark in the track direction, and located on a radial straight line with respect to the center of the disk. A disc-shaped optical recording medium configured to be recorded on, and divided into at least two servo zones in a radial direction,
An optical recording medium, wherein the number of the servo areas per one turn in the outer servo zone is larger than the number of the servo areas per one turn in the inner servo zone. 2. A servo area is composed of a clock mark for synchronization, a first wobble mark and a second wobble mark, and a plurality of the servo areas are intermittently provided on one track on a spiral or concentric circular track. And the clock marks are arranged at equal intervals on a track center line and on a straight line radiating with respect to the center of the disk, and the first and second wobble marks are equidistant from each other with respect to the track center line. Information is provided between the servo areas, which are separated from each other in the outer peripheral direction and the inner peripheral direction, are provided in front of or behind the clock mark in the track direction, and are located on a straight line radiating from the center of the disk. A disc-shaped optical recording medium configured to record information in an area, which is divided into at least two servo zones in a radial direction,
The number of the above-mentioned servo areas per one turn in the outer peripheral servo zone is larger than that per one turn in the inner servo zone, each servo zone is further divided into a plurality of data zones, and the innermost circumference in each data zone The data bit lengths recorded on the tracks are almost equal to each other, and the data bit lengths are increased in proportion to the radius of the disk in the same data zone, and at least one information area per one circumference is recorded. An optical recording medium in which an address is provided on the optical disk and the bit length of the address is increased in proportion to the radius in the same servo zone. 3. A servo area is composed of a clock mark for synchronization, a first wobble mark and a second wobble mark, and a plurality of the servo areas are intermittently provided on a spiral or concentric track per revolution. And the clock marks are arranged at equal intervals on a track center line and on a straight line radiating with respect to the center of the disk, and the first and second wobble marks are equidistant from each other with respect to the track center line. Information is provided between the servo areas so as to be separated from the outer circumferential direction and the inner circumferential direction, provided in front of or behind the clock mark in the track direction, and located on a radial straight line with respect to the center of the disk. A disc-shaped optical recording medium configured to be recorded on, and divided into at least two servo zones in a radial direction,
The number of the servo areas per one turn in the servo zone on the outer circumference is twice the number of the servo areas per one turn in the servo zone on the inner circumference, and the clock mark and the disk center in the servo zone on the inner circumference are set. An optical recording medium in which a central angle formed by a connecting straight line and a straight line connecting the first or second wobble mark and the disc center is twice as large as that in a servo zone on the outer periphery thereof. 4. The optical recording medium according to claim 2, wherein one sector has a predetermined amount of information, and an address for identifying a position is provided at the head of each sector. 5. The optical recording medium according to claim 1, wherein at least one servo area is arranged on a radial straight line from the disk center in all servo zones. 6. The optical recording medium according to claim 2, wherein at least one servo area is arranged on a radial straight line from the center of the disk in all servo zones, and an address area is provided in the information area immediately after that.