JPH11353685A - Optical disk device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance a recording density by allowing a device to have a sufficient reproducing ability even in the case of reproducing the outer peripheral side of an optical disk and improving the durability at the time of repeatedly reproducing in an inner peripheral side of the disk when the device adopts a one CAV(constant angular velocity) system. SOLUTION: This optical disk device uses a CAV system in which the rotation of an optical disk 15 is controlled at a constant angular velocity and also the recording area of the optical disk is divided into plural zones and average densities in every zone are made roughly constant by changing recording frequencies in every zone. In this case, the device has an MPU(microprocessor unit) 30 performing a laser power control raising the power of a reproducing laser as the reproduction position of the optical disk 15 is moved from the inner peripheral side to the outer peripheral side and lowering the power of the reproducing laser as the reproduction position of the disk is moved from the outer peripheral side to the inner peripheral side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling the rotation of an optical disk at a constant rotational angular velocity, dividing the recording area of the optical disk into a plurality of zones, changing the recording frequency for each zone, and averaging each zone. The present invention relates to an optical disk device that employs a so-called zone CAV method that makes recording density substantially constant.

[0002]

2. Description of the Related Art Conventionally, the rotation control method of an optical disc has been a constant linear velocity (CLV) method or a constant angular velocity (CAV).
There are various types such as methods. As shown in FIG. 5, some of the optical disk rotation control systems include a recording area of an optical disk whose rotation is controlled at a constant rotation angular velocity by a plurality of zones Z.
.., ZX, the recording frequency (recording band) is changed for each of the zones Z0 to ZX, and the average recording density of each zone is substantially constant. There is also a method called CAV method. According to the zone CAV, compared to a general CAV method (a CAV method in which an optical disc recording area is not zoned),
It is characterized in that the overall recording capacity of the optical disk can be increased, and that the rotation control is easier than in the CLV method.

[0003]

In the above-described zone CAV system, CAV control is basically performed.
As the scanning position on the optical disk by the laser spot shifts from the inner circumference to the outer circumference, the linear velocity at the scanning position increases (the linear velocity increases in proportion to the value of the disk radius R). Conversely, as the scanning position by the laser spot moves from the outer peripheral side to the inner peripheral side, the linear velocity on the scanning position becomes slower. As described above, when the linear velocity on the inner peripheral side is lower than that on the outer peripheral side, even if, for example, the laser emission power is the same, the amount of temperature rise at the position on the optical disc where the laser spot is formed becomes smaller. The circumference side is larger than the outer circumference side.

Here, in the case of an optical disk (for example, a phase-change disk or a magneto-optical disk) in which data is recorded by raising the temperature of a recording area on the disk to a predetermined value or more by the heat of a laser beam, reproduction is performed. Although the laser emission power at the time of recording is weaker than that at the time of recording, even if the laser emission power at the time of reproduction is concerned, for example, if the laser light irradiation time for a position on the optical disk is long, the temperature at that position rises, and as a result The temperature may reach the recordable temperature. As described above, if the temperature on the optical disk rises to the recordable temperature at the time of reproduction, the already recorded data will be erased by mistake.

[0005] For this reason, the laser light emission power at the time of reproduction is set to a value that does not cause erroneous erasure of already recorded data even at the time of reproduction on the inner peripheral side.

On the other hand, in the case of the zone CAV system, the recording frequency (recording band) is increased as the zone moves from the inner zone to the outer zone (the recording frequency is increased in proportion to the value of the disc radius R of each zone). By doing so, the overall recording capacity of the optical disk is increased as compared with the general CAV method, and the average recording density of each zone is made substantially constant. In other words, in the zone CAV method, the recording frequency in the outer zone is increased in order to increase the recording capacity and to make the average recording density of each zone substantially constant.

However, as the frequency of the recording data increases, it becomes more difficult to read the data during reproduction. That is, the RF amplifier generally used in the optical disk device has a characteristic that when the frequency of the reproduction signal from the optical disk increases, the band is limited, and the amplitude of the reproduction signal deteriorates. Also, in general,
As the signal frequency increases, the noise component also increases, and substantial S /
It is known that N (signal to noise ratio) deteriorates. Further, on the outer peripheral side of the optical disk, the influence of defocus due to the surface deflection of the optical disk becomes large, and other factors such as servo performance and variations in manufacturing the disk are disadvantageous for reading data during reproduction. Become.

If the laser emission power at the time of reproduction is increased, the C / N (carrier to noise ratio) is increased, and even if the recording frequency is high as in the above-mentioned outer peripheral zone, the deterioration of the S / N is reduced. In addition, it is more resistant to defocus such as surface runout, variation in performance, and the like, but increasing the laser emission power causes the above-described problem of data erasure on the inner peripheral side of the disk.

As described above, in the conventional zone CAV type optical disk, the outer peripheral side has a higher reproduction capability than the inner peripheral side due to the limitation of the signal band and the reduction of the servo capability due to the disk structure. Disadvantaged. Also,
Since the laser emission power at the time of reproduction is constant, the durability at the time of repeated reproduction at the inner peripheral side is lower than that at the outer peripheral side. For this reason, the laser emission power at the time of reproduction has to be set to a value (low value) at which there is no problem in repetitive reproduction on the inner peripheral side, although higher power is more advantageous. As a result, the reading ability on the outer peripheral side has been reduced, and therefore, the recording density on the optical disk must be suppressed to a value that satisfies the outer peripheral reading ability.

Therefore, the present invention has been made in view of such a situation, and when the zone CAV method is adopted, the present invention has a sufficient reproducing ability even when reproducing the outer peripheral side of an optical disk. It is another object of the present invention to provide an optical disc device that can improve the durability at the time of repeated reproduction on the inner peripheral side and can further increase the recording density.

[0011]

An optical disk apparatus according to the present invention is an optical disk apparatus using a zone angular velocity constant control method, and increases the reproduction laser power as the reproduction position of the optical disk is shifted from the inner side to the outer side. By having the power control means, the above-mentioned problem is solved.

Further, the optical disk device of the present invention is an optical disk device using a zone angular velocity constant control method,
The above-mentioned problem is solved by providing a laser power control means for lowering the reproduction laser power as the reproduction position of the optical disc is shifted from the outer side to the inner side.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows a schematic configuration of an optical disk recording / reproducing apparatus which is an embodiment of the optical disk apparatus of the present invention.

In FIG. 1, a laser diode 10
The laser light emitted from the laser beam enters the beam splitter 12. The beam splitter 12 transmits the laser light from the laser diode 10 and guides the laser light to the reflection mirror 13, and reflects a part of the laser light and guides the laser light to the light-emitting power monitoring photodetector (MPD) 11.

The light emission power monitoring photodetector 11 photoelectrically converts the laser light reflected by the beam splitter 12 to generate a monitor current Im, and converts the monitor signal Im to APC (Automatic Power Control). It is sent to the error amplifier 7 operating as a circuit.
The error amplifier 7 is also supplied with the laser power and the signal Iout from the pulse control circuit 1. That is, the laser power and pulse control circuit 1 at this time generates a reference current as a reference for laser emission in the laser diode 10 as the signal Iout, and sends the signal Iout as the reference current to the error amplifier 7. In the error amplifier 7, the monitor current Im
An adjustment current for adjusting the current flowing through the laser diode 10 is generated based on the reference current signal Iout and the reference current signal Iout so that APC always becomes Im = Iout. The adjustment current is supplied to the base terminal of the NPN transistor 8, and the transistor 8 is driven by the adjustment current. Thus, the laser emission power from the laser diode 10 is always controlled to a constant value.

Here, the signal Iout output from the laser power and co-pulse control circuit 1 is MPU
(Micro processing unit)
It is controlled by. That is, the registers 5 and 6 inside the laser power and pulse control circuit 1
Power command value (power set data) from MPU 30
The values of the registers 5 and 6 are sent to the D / A (digital / analog) converters 3 and 4, respectively. The outputs of these D / A converters 3 and 4 are connected to a switch SW
Sent to The switch SW is switched by a signal modulated by a write pulse modulator 2 based on write data to be described later. As a result, the laser power and pulse control circuit 1 outputs various light emission instructions (that is, a signal Iout). And the respective laser emission powers at the time of erasure, recording, and reproduction can be controlled. In FIG. 1, two types of registers 5, 6 are shown.
And D / A converters 3 and 4 are described.

On the other hand, the laser beam transmitted through the beam splitter 12 and reflected by the reflection mirror 13 is focused on the surface of the optical disk 15 by the objective lens 14. The optical disk 15 is driven to rotate by a spindle motor 16, and the light reflected on the surface of the optical disk 15 passes through an objective lens 14 and further passes through a reflection mirror 13.
And is guided to the beam splitter 12. At this time, the beam splitter 12
The reflected light from the light is further reflected and guided to a photodetector (PD) 17 for signal reproduction. The photo detector 17 is
The incident light is subjected to photoelectric conversion to generate a reproduction RF signal, and the reproduction RF signal is sent to current-voltage converters (IV) 18 and 22. The current-to-voltage converter 18 extracts various servo signals as voltage signals from the reproduced RF signal, which is a current signal, and the current-to-voltage converter 22 converts data (addresses and data recorded on the optical disc 15). ) Is extracted from the reproduced RF signal.

The current-voltage converter 18 generates a focus signal, a tracking signal, a total light amount signal (SUM) on the disk, and the like as the servo signals. The focus signal is sent to an AGC (Automatic Gain Control) amplifier 19, and the tracking signal is sent to an AGC amplifier 20. These AGC amplifiers 1
Reference numerals 9 and 20 perform gain adjustment of the focus signal and the tracking signal based on the total light amount signal (SUM). That is, in order to avoid that the focus signal and the tracking signal change in value due to the light emission power of the laser diode 10, the total light amount signal (SU
M). The output signal from the AGC amplifier 19 becomes a focus error signal FE, and the output signal from the AGC amplifier 20 becomes the tracking error signal TE.
Becomes The focus error signal FE and the tracking error signal TE are sent to the MPU 30.

The MPU 30 has a focus servo unit for performing focus servo based on the focus error signal FE, and a tracking servo unit for performing tracking servo based on the tracking error signal TE. In the focus servo section of the MPU 30, the focus error signal FE is converted into data by an A / D (analog / digital) converter 34 and taken in, and the difference calculation section 33 outputs a focus command value from a focus command value generation section 37. After passing the difference through a compensation filter 32, the D / A (digital / analog) converter 31
To generate a focus drive control signal.

The focus drive control signal is sent to a driver 29 for driving a two-axis actuator 28, and the driver 29 drives a focus coil of the two-axis actuator based on the focus drive control signal. As a result, the objective lens 14 provided on the biaxial actuator 28 is driven and controlled in the focus direction, and the focus is always focused on the surface of the optical disk 15.

Although not shown, the MPU
The 30 tracking servo units basically have the same configuration as the focus servo unit. That is, in the tracking servo section, the tracking error signal T
E is converted into data by an A / D converter, taken in, and compared with a tracking command value by a difference calculator, and the difference is passed through a compensation filter, and then sent to a D / A converter to perform tracking drive control. Generate a signal.

The tracking drive control signal is sent to a driver 29, and the driver 29 drives the tracking coil of the biaxial actuator based on the tracking drive control signal. As a result, the objective lens 14 provided on the biaxial actuator 28 is driven and controlled in the tracking direction, so that the laser spot is always focused on the track of the optical disk 15.

On the other hand, the reproduction R
The reproduced signal extracted from the F signal is sent to the VGA and the EQ amplifier 23. The VGA and EQ amplifier 23
Is composed of a VGA (variable gain amplifier) and an EQ (equalizer: equalizer). The VGA and the EQ amplifier 23 optimize the signal amplitude and perform equalization filtering.

The reproduced signal that has been subjected to amplitude optimization and equalization filtering by the VGA and EQ amplifier 23 is converted into a digital signal by a slicer 24, and further converted to a digital signal.
LL (Phase-Locked Loop) circuit 26
Sent to The PLL circuit 26 includes the slicer 24
A read clock is taken out from the digital reproduction signal from the CPU and the read clock is sent to the data decoder 45 and the address detector 44 of the optical disk control (ODC) block together with the read data.

The optical disk control block 38
Then, data reproduced from the optical disk 15 while performing address management is transferred to the SCSI (Small Computer System In
terface) to the host. That is, the data decoder 45 of the optical disk control block 38 decodes the read data based on the read clock, and the address detector 44 detects the address data from the read data based on the read clock. The address data is sent to a table 36 of the MPU 30 described later. The decoded read data is stored in the read buffer 42.
After a predetermined amount of data is stored, the data is sent to the host (not shown) via the SCSI controller 40 and the terminal 39.

On the other hand, when data is recorded on the optical disk 15, data to be recorded on the optical disk 15 and address information are supplied from the host via the terminal 30. The data to be recorded and the address information supplied from the host side are stored in the optical disk control block 3.
After a predetermined amount is accumulated in the write buffer 43 via the SCSI controller 40 of No. 8, the data is sent to the data encoder 46. The data encoder 46 encodes the data to be recorded and the address information to generate write data, and generates a write clock. The write clock and the write clock are used for the write pulse modulation of the laser power and pulse control circuit 1. Send to Part 2. Further, a write gate signal is generated from the gate generator 41 of the optical disk control block 38, and this write gate signal is also sent to the write pulse modulation section 2 of the laser power and pulse control circuit 1.

The write pulse modulator 2 of the laser power and pulse control circuit 1 converts the write data into a signal Iout at the timing of the write gate signal, whereby the laser emission of the laser diode 10 is modulated by the write data. Will be. The laser light from the laser diode 10 is condensed on the surface of the optical disk 15 via the beam splitter 12, the reflection mirror 13, and the objective lens 14, as described above, whereby pits are formed on the optical disk 15. .

When the optical disk 15 is a so-called phase-change type optical disk, recording is performed by modulating the laser emission power. However, when the optical disk 15 is a so-called magneto-optical disk, an external magnetic field is applied by an external magnet. It is necessary to generate it at the same time.

Here, the optical disk recording / reproducing apparatus of this embodiment employs the zone CAV method as shown in FIG.

The optical disk recording / reproducing apparatus according to the present embodiment has, in addition to the structure for performing the above-described basic operation at the time of recording / reproducing, furthermore, the inside of the MPU 30 for each zone (the position of each zone is calculated from address information). The table 36 has a correspondence table of appropriate read power (laser emission power at the time of reproduction) and the start address of the zone, and controls the laser emission power based on the read power and the start address of each zone, so that the optical disk is controlled. Has a sufficient reproduction capability even in the case of reproducing the outer peripheral side, can improve the durability at the time of repeated reproduction on the inner peripheral side, and can further increase the recording density.

As described above, in the zone CAV system,
Basically, since CAV control is performed, the linear velocity at the scanning position becomes slower as the scanning position by the laser spot moves from the outer peripheral side to the inner peripheral side. However, even if the values are the same, the temperature on the inner peripheral side is likely to rise, and as a result, the recording data on the inner peripheral side may be erased. Therefore,
The laser emission power at the time of the reproduction is set to a limit value so that the recorded data is not erroneously erased even during the reproduction on the inner peripheral side. The limit value of the laser emission power on the inner peripheral side during this reproduction (light intensity that does not cause erroneous erasure of the recorded data) is smaller than that on the outer peripheral side.

The curve A in FIG. 2 shows the relationship between the radial position of the optical disk and the limit value of the laser emission power at each position. The horizontal axis in FIG. 2 shows the radial position (unit: mm) of the optical disc, and the right vertical axis shows the limit value (unit: mW) of the laser emission power. The following are examples. From the curve A in FIG. 2, it can be seen that the limit value of the laser emission power at the time of reproduction is up to 2 mW on the outer circumference side, whereas the limit value is 1.2 mW on the inner circumference side. That is, from the curve A in FIG. 2, the limit value is lower on the inner circumference side than on the outer circumference side,
Therefore, it can be seen that the durability of repeated reproduction (repeated read) is lower on the inner peripheral side than on the outer peripheral side.

As described above, in the case of the zone CAV system, as the zone moves from the inner zone to the outer zone,
By increasing the recording frequency, the overall recording capacity is increased, and the average recording density for each zone is made substantially constant. Therefore, data reading on the outer peripheral side is more than that on the inner peripheral side. Is at a disadvantage.

The curve B in FIG. 2 shows the position of the optical disk in the radial direction, the current-voltage converter 22 and the VGA at each position.
And the relationship with the amplitude of an RF amplifier such as the EQ amplifier 23. The left vertical axis of FIG. 2 shows the amplitude (unit: dB) of the RF amplifier. From the curve B in FIG.
In the F-amplifier, it can be seen that when the frequency rises like the reproduced signal on the outer peripheral side, the band is restricted and the amplitude deteriorates, the noise component also increases and the S / N substantially deteriorates. On the outer peripheral side, the influence of defocus due to the surface deflection of the disk is large, and it is disadvantageous for reading due to various factors such as other servo and disk manufacturing.

On the other hand, the laser emission power at the time of reproduction greatly affects the reading ability at the time of reproduction. For example, as shown by a curve C in FIG.
(Carrier-to-noise ratio) increases and the S / N does not deteriorate much even when the recording frequency is high as in the outer peripheral zone described above.
In addition, it is known that it is also strong against defocus such as surface deviation, variation in performance, and the like. The horizontal axis of FIG. 3 represents the laser emission power (unit: mW) during reproduction, and the vertical axis represents C
/ N (unit: dB), and an optical disc having a recording area with a radius of 30 mm to 60 mm is taken as an example.

As described above, in the present embodiment, the limit value of the laser emission power is maintained at the time of reproduction on the inner peripheral side, while, on the outer peripheral side, which is disadvantageous in readability at the time of reproduction, at the time of reproduction. By increasing the laser emission power (read power), the S / N is improved and the read / read capability is enhanced.

That is, in the present embodiment, at the time of reproduction, as shown by the curve D in FIG. 4, as the scanning position by the laser spot shifts from the inner peripheral side to the outer peripheral side, the read power is increased. As shown by curve E in FIG. 4, the read / read capability on the outer peripheral side is increased while preventing data destruction on the side (FIG. 4 means that the read / read capability is less deteriorated than in FIG. 2). doing). 4 shows the relationship between the radial position of the optical disk and the read power (right vertical axis, unit: mW) at each position, and the curve E shows the radial position of the optical disk and the signal quality at each position. C / N (left vertical axis, unit dB)
As an optical disc, the recording area has a radius of 30 mm to 60 m.
For example, an example in which the number is set to m is given.

In the case of the outer peripheral side, since the limit value of the read power is higher than that of the inner peripheral side, even if the outer peripheral side read power is higher than that of the inner peripheral side, data will not be destroyed. Further, in the present embodiment, an example in which the read power is changed for each zone is given, but this is one means, and it is possible to change the power more roughly or vice versa. Which of these is adopted may be determined according to the capability of the system. When the read power is changed more broadly than each zone, for example, it is conceivable that the read power is changed for each zone group in which a plurality of adjacent zones are put together. When the read power is changed more finely than each zone, for example, it is conceivable that the read power is changed for each portion obtained by subdividing each zone.

The optical disk recording / reproducing apparatus of this embodiment is provided with the following configuration in order to realize read power control accompanying the movement of the reproducing position from the inner peripheral side to the outer peripheral side described above.

That is, the MPU 30 stores addresses A1 to AX corresponding to areas (for example, each zone) on the optical disk.
And a read power setting parameter P1 to PX indicating the value of the read power.

Then, for example, the optical disk 1
When receiving a read command instructing to read data at a certain position on the optical disk 5, the optical disk recording / reproducing apparatus seeks the read position to a position on the optical disk 15 corresponding to the address specified by the command. At this time, an address based on the read command or address data detected by the address detector 44 of the optical disc control block 38 from the read data (corresponding to the addresses A1 to AX) is given to the MPU 30. Table 36
, The read power setting parameter corresponding to the address is read.

The read power setting parameter read from the table 36 is sent to the power command value generator 35. The power command value generator 35 generates power set data (power command value) based on the read power setting parameter, and sends the power set data to the registers 5 and 6 of the laser power and pulse control circuit 1. . Thereby, the signal Iout sent from the laser power and pulse control circuit 1 to the error amplifier 7 becomes a signal for optimizing the read power.

As described above, according to the optical disk recording / reproducing apparatus of the present embodiment, when the zone CAV method is adopted, sufficient reproducing capability is obtained even when reproducing the outer peripheral side of the optical disk 15. You can get
Further, the durability at the time of repeated reproduction on the inner peripheral side can be improved, and the recording density can be further increased.

[0045]

As is apparent from the above description, in the present invention, when the zone angular velocity constant control method is used, the reproduction laser power is increased as the reproduction position of the optical disk is shifted from the inner side to the outer side. Alternatively, by lowering the reproducing laser power as the reproducing position of the optical disk is shifted from the outer peripheral side to the inner peripheral side, even when reproducing the outer peripheral side of the optical disk, it has a sufficient reproducing capability. The durability at the time of repeated reproduction on the side can be improved, and the recording density can be further increased.

[Brief description of the drawings]

FIG. 1 is a block circuit diagram showing a schematic configuration of an optical disk recording / reproducing apparatus according to an embodiment of the present invention.

FIG. 2 is a characteristic diagram illustrating a relationship between a radial position of an optical disc and a limit value of laser emission power at each position, and a relationship between a radial position of the optical disc and an amplitude of an RF amplifier at each position.

FIG. 3 shows C / N of laser emission power and signal quality during reproduction.
It is a characteristic view showing the relationship with.

FIG. 4 is a characteristic diagram showing a relationship between a radial position of the optical disc and read power at each position, and a relationship between a radial position of the optical disc and C / N of signal quality.

FIG. 5 is a diagram used for explaining a zone CAV method.

[Explanation of symbols]

1 laser power and pulse control circuit, 2
Light pulse modulator, 3,4 D / A converter, 5,6
Register, 7 error amplifier, 8 transistor,
Reference Signs List 10 laser diode, 11 photodetector for light emission power monitor, 12 beam splitter, 1
3 reflection mirror, 14 objective lens, 15 optical disk, 16 spindle motor, 17 photodetector, 18, 22 current-voltage converter, 19, 20
AGC amplifier, 23 VGA and EQ amplifier, 2
4 slicer, 26 PLL circuit, 29 driver, 28 2-axis actuator, 30 MPU,
31 D / A converter, 32 compensation filter, 33
Difference calculator, 34 A / D converter, 35 power command value generator, 36 table, 37 focus command value generator, 38 optical disc control block,
40 SCSI controller, 41 gate generator, 42 read buffer, 43 write buffer, 44 address detector, 45 data decoder, 46 data encoder

Claims (10)

[Claims] An optical disk is controlled to rotate at a constant rotational angular velocity, a recording area of the optical disk is divided into a plurality of zones, a recording frequency is changed for each zone, and an average recording density for each zone is substantially constant. An optical disk device using a constant zone angular velocity control method, comprising: a laser power control means for increasing a reproduction laser power as a reproduction position of the optical disk is shifted from an inner peripheral side to an outer peripheral side. 2. The laser power control means includes a correspondence table between a plurality of reproduction position addresses on an optical disk and reproduction laser power, and reproduces the reproduction laser power extracted from the correspondence table based on the reproduction position address of the optical disk. The optical disk device according to claim 1, wherein the setting is performed. 3. The optical disk device according to claim 2, wherein each reproduction position address in the correspondence table corresponds to each address indicating each zone. 4. The optical disk apparatus according to claim 2, wherein each reproduction position address in the correspondence table corresponds to each address obtained by subdividing each zone. 5. The optical disk device according to claim 2, wherein each reproduction position address in the correspondence table corresponds to each address in which the plurality of zones are put together. 6. An optical disk is controlled to rotate at a constant rotational angular velocity, a recording area of the optical disk is divided into a plurality of zones, a recording frequency is changed for each zone, and an average recording density for each zone is substantially constant. An optical disk apparatus using a constant zone angular velocity control method, comprising: a laser power control means for lowering a reproduction laser power as a reproduction position of the optical disk is shifted from an outer peripheral side to an inner peripheral side. 7. The laser power control means includes a correspondence table between a plurality of reproduction position addresses on the optical disc and reproduction laser power, and reproduces the reproduction laser power extracted from the correspondence table based on the reproduction position address of the optical disc. 7. The optical disk device according to claim 6, wherein the setting is performed. 8. The optical disk device according to claim 7, wherein each reproduction position address in the correspondence table corresponds to each address indicating each zone. 9. The optical disk device according to claim 7, wherein each reproduction position address in the correspondence table corresponds to each address obtained by subdividing each zone. 10. Each reproduction position address in the correspondence table is:
8. The optical disk device according to claim 7, wherein each of the plurality of zones corresponds to each address.