JPH09306091A - Optical recording/reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce difference in the rotational number of a disk due to the access position of a pickup and allow a change in the rotational number of the disk within a short time when changing the rotational number. SOLUTION: The device is provided with a disk 1 having an information recording region for information recording, a pickup 4 placed close to the disk 1, a constant linear velocity rotation driving section for the disk 1, a constant angular velocity rotation driving section for the disk 1, and a switching control section which switches the connection of the disk 1 to the side of constant linear velocity rotation driving section or the side of constant angular velocity rotation driving section. In this case, the information recording region is halved to an inner peripheral zone and an outer peripheral zone in the radial direction. When the pickup 4 accesses the outer peripheral zone, the disk 1 is switched and connected to the side of constant linear velocity rotation driving section and when the pickup 4 accesses the inner peripheral zone, the disk 1 is switched to the side of constant angular velocity rotation driving section.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical recording / reproducing apparatus and, more particularly, to a disc with a constant angular velocity depending on whether a pickup accesses an inner zone or an outer zone of the disc when the disc is rotationally driven. The present invention relates to an optical recording / reproducing apparatus that switches between rotational driving and constant linear velocity rotational driving.

[0002]

2. Description of the Related Art Generally, when recording information on a disc-shaped recording medium (hereinafter referred to as a disc), an optical recording / reproducing apparatus is used to increase the storage capacity of the disc as much as possible so that the disc has a constant linear velocity (CLV). ) Rotational driving is performed so that information is written in the information recording area and information is read from the information recording area. Also,
In a known optical recording / reproducing apparatus, index information is recorded in advance in a lead-in area provided on the inner peripheral side of the information recording area of the disc in order to facilitate retrieval of recorded information on the disc. Things are also known.

When the disk is driven to rotate at a constant linear velocity, the rotational speed of the disk increases according to the disk access position of the pickup, that is, the closer the access position of the pickup is to the center of the disk. Must. When reading the index information recorded in the lead-in area on the inner circumference of the disc, the index information may be erroneously read unless the high rotation speed of the disc is accurately controlled. If you misread the information,
Unwanted information may be recorded in the information recording area, or some of the information recorded in the information recording area may be erased.

In order to avoid the occurrence of such an undesired situation, when the pickup accesses the information recording area of the disc, the disc is driven to rotate at a constant linear velocity (CLV) to record information on the disc or from the disc. Information is read out, and when the pickup accesses the lead-in area on the inner circumference of the disc, the disc is driven to rotate at a constant angular velocity (CAV), and the rotation speed of the disc is higher than that at the time of constant linear velocity (CLV) rotation. A recording / reproducing apparatus for reading index information recorded in the lead-in area of the disc so as to be slower has already been developed. One example thereof is disclosed in Japanese Utility Model Laid-Open No. 62-22763. .

[0005]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
The recording / reproducing apparatus disclosed in Japanese Patent No. 763, for the time being, rotates the disk by a constant linear velocity (CLV) rotation drive and a constant angular velocity (CA).
V) The drive is switched to rotational drive. However, when the disc is driven at a constant angular velocity (CAV), the pickup is limited to the time when the index information recorded in the lead-in area of the disc is read. When accessing the inner peripheral part of the information recording area, the number of rotations of the disk must be increased considerably compared to when accessing the outer peripheral part of the information recording area, and the disk is rotated at a constant linear velocity (CLV). It is necessary to select a motor having a high rotation speed as a motor to be driven. On the other hand, a motor with a high rotational speed has a low motor torque constant, and when such a motor is used, the acceleration / deceleration torque of the motor decreases, making it impossible to perform high-speed access to the disk. , In particular, when the pickup seeks from the inner circumference side where the disc rotation speed is high to the outer circumference side where the disc rotation speed is low, it takes time to reduce the disc rotation speed, and the disc is set to a predetermined rotation speed. Therefore, there is a problem that a relatively long time is required.

The present invention solves such a problem, and an object thereof is to reduce the disc rotational speed difference based on the disc access position of the pickup and to change the disc rotational speed within a short time when the disc rotational speed is changed. An object of the present invention is to provide an optical recording / reproducing device that can be changed.

[0007]

In order to achieve the above object, an optical recording / reproducing apparatus according to the present invention divides an information recording area of a disc into an inner peripheral zone and an outer peripheral zone in a radial direction, and a pickup is provided. When accessing the outer zone,
It is provided with a means for rotating the disk at a constant linear velocity (CLV) so as to rotate the disk at a constant angular velocity (CAV) when the pickup accesses the inner circumferential zone.

According to such means, when the pickup accesses the inner peripheral zone of the disc, the disc is rotationally driven at a constant angular velocity (CAV). Therefore, when accessing the entire information recording area, a constant line is used. Speed (CLV)
It is not necessary to raise the maximum value of the disk rotation speed so much as compared with a known recording / reproducing apparatus that is rotationally driven by, and it becomes possible to use a high torque motor as a motor for rotating the disk. By using the motor, it is possible to shorten the time required to change (acceleration / deceleration) the disk rotation speed to a target rotation speed.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION In an embodiment of the present invention, an optical recording / reproducing apparatus has a disc having an information recording area in which information is recorded, a pickup arranged in proximity to the disc, and a constant linear velocity of the disc. A constant linear velocity rotation drive unit that is rotationally driven by CLV, and a constant angular velocity (CA
V) is provided with a constant angular velocity rotary drive unit and a switching control unit for selectively switching the connection of the disk to the constant linear velocity rotary drive unit side or the constant angular velocity rotary drive unit side. When the pickup divides the inner and outer zones into two in the radial direction of the disc and the pickup accesses the outer zone, the disc is switched and connected to the constant linear velocity rotary drive unit to rotate at a constant linear velocity (CLV). Then, when the pickup accesses the inner circumferential zone, the disc is switched and connected to the constant angular velocity rotary drive unit side so that the constant angular velocity (CA
V) is used to drive the rotation.

In a preferred example of the embodiment of the present invention, the rotational speed of the disk when driven to rotate at a constant angular velocity is set to be lower than the rotational speed when driven to rotate at a constant linear velocity in the inner peripheral zone. .

Further, in a preferred example of the embodiment of the present invention, the number of rotations of the disk at the boundary between the inner peripheral zone and the outer peripheral zone depends on whether the disk is driven to rotate at a constant angular velocity or the constant linear velocity drive section. Are chosen to be equal.

Further, in a preferred example of the embodiment of the present invention, the constant angular velocity rotary drive unit and the constant linear velocity rotary drive unit are:
Both have a wide capture range.

According to the embodiment of the present invention, when the pickup accesses the outer peripheral zone of the disc, the disc is rotationally driven at a constant linear velocity (CLV) as in a known recording / reproducing apparatus. On the other hand, when the pickup accesses the inner zone of the disc, the disc is driven to rotate at a constant angular velocity (CAV).
The maximum value does not become so high. Therefore, it becomes possible to use a high torque motor as a motor for rotating the disk, and by using the high torque motor, it is possible to shorten the time until the disk rotation is changed to the target rotation speed (acceleration / deceleration). You can

[0014]

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

FIG. 1 is a block diagram showing a schematic structure of an embodiment of an optical recording / reproducing apparatus according to the present invention, and FIG. 2 is a structure of a disk used in the optical recording / reproducing apparatus shown in FIG. It is a top view which shows an example.

As shown in FIG. 1, the optical recording / reproducing apparatus includes a disk-shaped recording medium (disk) 1 and a motor 2.
, A motor driver 3, a pickup (PU) 4,
A constant linear velocity (CLV) control block 5, a frequency deviation detection unit 6, a reference signal generation unit 7, a control unit (CPU) 8,
It includes a switching unit 9 and a rotation speed detection unit 10.

As shown in FIG. 2, the disc 1 is provided with an information recording area 11 and a lead-in area 12. The information recording area 11 includes the outermost peripheral portion and the innermost peripheral portion of the disc 1. Is a part having a large number of tracks (not shown) and is divided into an inner peripheral zone 11 (1) and an outer peripheral zone 11 (2). , Which is formed inside the information recording area 11 in the inner peripheral portion of the disc 1 and also has a plurality of tracks. The motor 2 has a rotating shaft coupled to a disk mounting portion (not shown), and rotates the disk 1 mounted on the mounting portion during rotation. Motor driver 3
Is electrically coupled to the motor 2 and drives the motor 2 to rotate at a predetermined rotation speed. Pickup 4 is disk 1
And is configured to be movable in the radial direction of the disc 1 for recording information on the disc 1 and reading recorded information from the disc 1. The constant linear velocity (CLV) control block 5 incorporates a frequency deviation detector 6 and a reference signal generator 7, receives the EFM signal detected by the pickup 4, and sends the constant linear velocity (CLV) control signal to the switching unit 9. Then, the deviation data is supplied to the control unit 8. The control unit 8 controls the operation of the entire optical recording / reproducing apparatus, receives the deviation data and the rotation speed detection signal, and supplies a constant angular velocity (CAV) control signal and a control switching signal to the switching unit 9, respectively. The switching unit 9 drives the motor 1 to rotate the disk 1 at a constant linear velocity (CLV).
The drive signal is switched to rotary drive or constant angular velocity (CAV) rotary drive, and the motor 2 is driven to rotate at constant linear velocity (CLV) or constant angular velocity (CAV) through the motor driver 3. Supply to the driver 3. The rotation speed detection unit 10 detects the rotation speed of the motor 2 and supplies a rotation speed detection signal to the control unit 8.

Next, FIG. 3 is a flow chart showing the operation history when the motor 2 is rotationally driven in the optical recording / reproducing apparatus shown in FIG.

The operation of the optical recording / reproducing apparatus of this embodiment will be described with reference to the flow chart shown in FIG.

First, in step S1, when the user gives an instruction to write information to the disc 1 or read information from the disc 1, the control section 8
Set the target time when a seek is performed.

Next, in step S2, the control unit 8
Calculates the target track position when a seek is performed.

Then, in step S3, the controller 8
Is based on the current rotation speed of the disc, and the step S2
The target track position calculated in step 3 is corrected, and the corrected target track position is calculated.

In the next step S4, the control unit 8
Determines whether the corrected target track position is the outer peripheral zone 11 (2) of the disk 1. Then, when it is determined that the corrected target track position is the outer peripheral zone 11 (2) (Y), the process proceeds to the next step S5, while
It is determined that the corrected target track position is not the outer zone 11 (2), that is, the inner zone 11 (1) (N).
If so, the process proceeds to another step S5 '.

Then, in step S5, the control unit 8
Calculates the target rotation speed of the motor 2 based on the corrected target track position.

Next, in step S6, the control unit 8
Accelerating or decelerating the current rotation speed of the motor 2 through the motor driver 3 to bring the rotation speed of the motor 2 close to the target rotation speed.

Then, in step S7, the controller 8
Adjusts a pickup position adjusting mechanism (not shown) to move the pickup 4 to the corrected target track position of the disc 1.

Then, in step S8, the controller 8
Causes the rotation speed detection unit 10 to detect the rotation speed of the motor 2, and receives a rotation speed detection signal obtained at that time.

Then, in step S9, the control unit 8
Determines whether or not the rotation speed of the motor 2 has reached the target rotation speed based on the received rotation speed detection signal. When it is determined that the number of revolutions of the motor 2 has reached the target number of revolutions (Y), the process proceeds to the next step S10, while the number of revolutions of the motor 2 has not yet reached the target number of revolutions. When the determination is (N), the process returns to the previous step S8, and the processes after step S8 are executed again.

Next, in step S10, the controller 8
Switches through the switching unit 9 so that the target steady rotation process of the motor 2 is performed.

Next, in step S11, the control unit 8 monitors the movement of the disc 1 in the pickup 4 to the corrected target track position.

Then, in step S12, the controller 8
Determines whether the pickup 4 has completed moving the disc 1 to the corrected target track position. And
When it is determined that the pickup 4 has completed the movement of the disc 1 to the corrected target track position (Y), the process proceeds to the next step S13, while the pickup 4 still moves to the corrected target track position of the disc 1. When it is determined that the process has not been completed (N), the process returns to the previous step S11, and the processes after step S11 are executed again.

Subsequently, in step S13, the control unit 8 switches the rotation control of the disk 1 to the constant linear velocity (CLV) control.

On the other hand, in step S5 ', the controller 8
Is the target number of rotations of the motor 2 at a constant angular velocity (CAV)
Set to a constant value of.

Next step S6 'to step S12'
The processing operations up to step S6 are the same as those in step S6 already described.
Since it is the same as the processing operation from step S12 to step S12,
The description of the processing operation from step S6 'to step S12' is omitted.

Finally, in step S14, the control unit 8 writes information to the disc 1 or reads recorded information from the disc 1 via the pickup 4, and when the information writing or the information reading is completed, This series of operations ends.

Here, in the optical recording / reproducing apparatus of the present embodiment, the case where the pickup 4 moves from the inner zone 11 (1) to the outer zone 11 (2) while reading the recorded information of the disc 1. Control switching is performed as follows.

In the constant linear velocity (CLV) control block 5, the frequency deviation detector 6 compares the reproduction frequency of the EFM signal continuously detected by the pickup 4 with the reference frequency generated by the reference signal generator 7. Then, deviation data (speed deviation) representing the comparison result is supplied to the control unit 8. This deviation data (velocity deviation) represents the current linear velocity information of the disc 1. When the disc 1 is rotated by a constant angular velocity (CAV), the disc 1 is moved by the pickup 4.
When the recorded information is read from the innermost zone 11 (1) of the innermost zone toward the outermost zone, the reproduction frequency gradually approaches the reference frequency from a state where the reproduction frequency is lower than the reference frequency. When the pickup 4 reaches the outermost peripheral portion of the inner peripheral zone 11 (1), the reproduction frequency matches the reference frequency. At this time, the control unit 8 controls the motor 2
The rotary drive of is switched from the constant angular velocity (CAV) rotary drive to the constant linear velocity (CLV) rotary drive. At the time of this switching, a transient speed fluctuation of about 10 Hz occurs in the rotation speed of the motor 2, but since the information reading follow-up frequency of the servo chip (not shown) used to drive the motor 2 is about 10 KHz, the speed fluctuation is No accompanying information read error occurs.

Instead of performing the above-described switching control, a target constant angular velocity (CA) is provided in the vicinity of a constant angular velocity (CAV) rotary drive and constant linear velocity (CLV) rotary drive switching region.
V) The rotational speed may be adjusted to match the current constant linear velocity (CLV) rotational speed, and then switched to the constant linear velocity (CLV) rotational drive.

Next, FIG. 4 is a characteristic diagram showing an example of the relationship between the radial access position of the disk and the disk rotation speed (motor rotation speed) in this embodiment.

As shown in the characteristic diagram of FIG. 4, the disc 1 has an information recording area 11 within a range of 25 mm to 58 mm from the center of the disc in the radial direction, and the information is recorded at a position of 37 mm from the center. The recording area 11 is divided into an inner zone 11 (1) and an outer zone 11 (2). The disc 1 is rotationally driven at a constant angular velocity (CAV) when the pickup 4 accesses the inner peripheral zone 11 (1), while the disc 1 is rotated when the pickup 4 accesses the outer peripheral zone 11 (2). It is driven to rotate at a linear velocity (CLV).

In this case, as shown by the solid line in FIG.
When the disc 1 is rotated at a constant linear velocity (CLV), the disc 1 is moved according to the disc access position of the pickup 4.
The rotation speed of (motor 2) is about 4000 (maximum value) to 25
While fluctuating within the range of 00 (minimum value),
When the disc 1 is rotated at a constant angular velocity (CAV), the disc 1 does not depend on the disc access position of the pickup 4.
The rotation speed of (motor 2) is approximately 4000 (constant value) and is substantially constant.

Incidentally, like a known recording / reproducing apparatus,
When the entire information recording area is rotationally driven at a constant linear velocity (CLV), as shown by the alternate long and short dash line in FIG. The number of rotations increases sequentially,
When the disc access position is at a position 25 mm from the center of the disc (the innermost peripheral portion of the information recording area), the rotation speed of the disc (motor) increases to about 6000.

The two dotted lines shown in FIG. 4 are recorded on the upper and lower lines of the data capture range in the servo chip (not shown) used to drive the motor 2, that is, the disk 1. FIG. 4 shows an example of the rotation speed allowable range (upper and lower limit range) of the motor 2 capable of reading the stored information. In the present embodiment, as shown in FIG. A wide capture range (± 50%) is used.

Next, FIG. 5 is a characteristic diagram showing an example of the relationship between the rotation speed of the motor 2 used in this embodiment and the acceleration / deceleration time. FIG. 5A shows the relationship between the rotation speed and the acceleration time. ,
(B) shows the relationship between the rotation speed and the deceleration time.

Now, a design procedure for designing the optical recording / reproducing apparatus of this embodiment when the motor 2 having the characteristics shown in FIGS. 4 and 5 is used will be described.

This design procedure is performed through the following 1 to 6.

1. Playback speed setting 2. Target access time setting 3. Setting of servo chip used 4. 4. Setting of acceleration / deceleration allowable value of motor 2 Motor characteristics and constant angular velocity (CAV) rotation speed setting 6. Indexing of the boundary between the inner peripheral zone 11 (1) and the outer peripheral zone 11 (2) of the disk 1, that is, the boundary between the constant angular velocity (CAV) rotary drive area and the constant linear velocity (CLV) rotary drive area.

First, 1. In setting the reproduction speed, the reproduction speed of the disc 1 is set to 12 times.

Next, 2. In setting the target access time, the time for the pickup 4 to move from the innermost circumference to the outermost circumference of the disc 1 (target access time) is set to 200 ms.

Then, 3. In the setting of the servo chip to be used, in the ideal case, if the motor 2 is accelerated or decelerated when the pickup 4 starts to move, the disk is not recorded when the pickup 4 reaches the corrected target track position. It is desirable that the constant linear velocity (CLV) of 1 is within an allowable range (data capture range) where the information on the disk 1 can be read. In this case, the permissible range (data capture range) from which information can be read depends on the circuit performance of the servo chip, and the target constant linear velocity (C
LV) can be handled within a range of about ± 1%, but recently, due to the progress of circuit manufacturing technology, it can also be supported within a range of a target constant linear velocity (CLV) of ± 10 to 50%. In this embodiment, the servo chip has a data capture range of ±
Use 50%.

Next, 4. Regarding the setting of the acceleration / deceleration allowable value of the motor 2, when the pickup 4 is accessed from the outermost circumference of the disk 1 to the innermost circumference, 6000− (60
(00 × 50%) = 3000 rpm, the rotation number at the outermost circumference of the disk 1 is from 2500 rpm to 30 rpm.
A motor having an acceleration time of 200 ms or less before reaching 00 rpm may be used. Similarly, when the pickup 4 accesses the disc from the innermost circumference to the outermost circumference, 2500+ (2500 × 50%) = 3750 rpm
Therefore, the rotation speed at the innermost circumference of the disk 1 is 6
A motor having a deceleration time from 200 rpm to 3750 rpm within 200 ms may be used.

Then, 5. Motor characteristics and constant angular velocity (CA
V) Regarding the setting of the rotation speed, the maximum value of the rotation speed of the motor 2 is Nmax, the torque constant is Kt, and the back electromotive force constant is K.
e, power supply voltage is V, electric resistance is R, frictional force is Td, and running resistance is Dw, Nmax = (Kt · VR−Td) / (Kt · Ke + D
w · R).

In the above equation, the counter electromotive voltage constant Ke and the torque constant Kt are in a proportional relationship, and the maximum value Nmax of the rotation speed is obtained.
In order to increase the rotation speed, for example, to obtain a rotation speed of 6000 rpm or more, a low torque motor having a small torque constant Kt, for example, a motor having a torque constant Kt of about 85 g · cm / A may be used.

Here, the curve l in FIGS. 5 (a) and 5 (b)
₁ is the acceleration / deceleration characteristic in the low torque motor with the torque constant Kt of 85 g · cm / A. As can be seen from this characteristic, when the low torque motor with the torque constant Kt of 85 g · cm / A is used, the motor acceleration The deceleration allowable value of 200 ms is greatly exceeded, which affects the access time.

Further, the curve l ₂ in FIGS. 5 (a) and 5 (b) is
The acceleration / deceleration characteristics when the motor acceleration / deceleration allowable value is within 200 ms, and the motor torque constant Kt at this time is 1
60g · cm / A, maximum speed Nmax is 5
It will be about 200 rpm.

From the above points, in the present embodiment, the rotational speed in the inner peripheral zone 11 (1) when driven to rotate at a constant angular velocity (CAV) is selected to be 4000 rpm.

Finally, 6. Regarding the determination of the boundary between the inner peripheral zone 11 (1) and the outer peripheral zone 11 (2) of the disk 1, that is, the boundary between the constant angular velocity (CAV) rotary drive area and the constant linear velocity (CLV) rotary drive area, , The radial position of the disk 1 where the constant linear velocity (CLV) rotation speed and the constant angular velocity (CAV) rotation speed are equal, that is, the boundary between the inner circumferential zone 11 (1) and the outer circumferential zone 11 (2) is r, the disc 1 Where v is the reproduction linear velocity and N is the constant angular velocity (CAV) rotation speed, r = (60v) / (2πN). In this case, the playback linear velocity v of the disc 1
Is 15.6 m / s when reading information from the 1.3 m / s disc 1 at 12 times speed, and the constant angular velocity (C
AV) Since the rotation speed during rotation drive is 4000 rpm, r = 37, and the position where the distance from the center of the disk 1 is 37 mm is the boundary between the inner peripheral zone 11 (1) and the outer peripheral zone 11 (2). Become.

As described above, according to this embodiment, the information recording area 11 of the disc 1 is radially arranged in the inner circumferential zone 11 (1).
And the outer zone 11 (2), and the pickup 4 is driven to rotate at a constant angular velocity (CAV) when the disc in the inner zone 11 (1) is accessed to suppress the upper limit of the number of revolutions of the disc 1. Therefore, the high torque motor 2 can be used to drive the disk 1, the target acceleration / deceleration characteristics can be easily obtained, and the disk access time can be shortened.

Further, according to this embodiment, since the upper limit of the rotation speed of the motor 2 is limited, the power consumption of the motor 2 and the motor driver 3 can be reduced.

[0060]

As described above, according to the present invention, when the pickup accesses the outer peripheral zone of the disc, the disc is rotatably driven at a constant linear velocity (CLV), whereas the pickup does not move inside the disc. When accessing the circumferential zone, the disk is driven to rotate at a constant angular velocity (CAV), and the maximum value of the disk rotation speed is suppressed. Therefore, a high torque motor can be used as a motor for rotating the disk. Thus, there is an effect that it is possible to shorten the time until the disk rotation is changed to the target rotation speed (acceleration / deceleration).

[Brief description of drawings]

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

FIG. 2 is a top view showing an example of the configuration of a disc used in the optical recording / reproducing apparatus shown in FIG.

FIG. 3 is a flowchart showing an operation history when the motor 2 is rotationally driven in the optical recording / reproducing apparatus shown in FIG.

FIG. 4 is a characteristic diagram showing an example of a relationship between a disk radial access position and a disk rotation speed (motor rotation speed) in the present embodiment.

FIG. 5 is a characteristic diagram showing an example of the relationship between the rotation speed of the motor used in this embodiment and the acceleration / deceleration time.

[Explanation of symbols]

 1 Disc-shaped recording medium (disk) 2 Motor 3 Motor driver 4 Pickup (PU) 5 Constant linear velocity (CLV) control block 6 Frequency deviation detection unit 7 Reference signal generation unit 8 Control unit (CPU) 9 Switching unit 10 Rotation speed detection 11 Information recording area 11 (1) Inner zone 11 (2) Outer zone 12 Lead-in section

Claims (4)

[Claims] 1. A disc having an information recording area in which information is recorded, a pickup arranged in proximity to the disc, a constant linear velocity rotary drive unit for rotationally driving the disc at a constant linear velocity, and a constant disc. A constant angular velocity rotary drive unit that is rotationally driven at an angular velocity, and a switching control unit that switches the connection of the disk to the constant linear velocity rotary drive unit side or the constant angular velocity rotary drive unit side, and the information recording area in the radial direction. When the pickup is divided into an inner peripheral zone and an outer peripheral zone and the pickup accesses the outer peripheral zone, the disc is switched and connected to the constant linear velocity rotary drive unit side, and when the pickup accesses the inner peripheral zone, An optical recording / reproducing apparatus, wherein the disk is switched and connected to a side of the constant angular velocity rotation drive section. 2. The rotational speed of the disk when driven to rotate at the constant angular velocity is set to be lower than the rotational speed when driven to rotate at the constant linear velocity in the inner peripheral zone. The optical recording / reproducing apparatus according to claim 1. 3. The number of rotations of the disk at the boundary between the inner peripheral zone and the outer peripheral zone is made equal between when the rotational drive is performed at the constant angular velocity and when the constant linear velocity drive unit is driven. The optical recording / reproducing apparatus according to claim 2, wherein the optical recording / reproducing apparatus is selected. 4. The optical recording according to claim 1, wherein the constant angular velocity rotary drive unit and the constant linear velocity rotary drive unit each have a wide capture range. Playback device.