JPH11110904A - Optical disk device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a constant linear velocity(CLV) system optical disk device in which the power consumption is low, vibration is reduced and a high speed access is made possible. SOLUTION: In the CLV system optical disk device, the target linear velocity value, which is normally constant, is controlled to a prescribed value in accordance with the situation. In the case of a random access, at the time just after seeking, the revolving speed of a disk is measured, an actual line velocity corresponding to the revolving speed is set as a temporary target value. Then, the value is gradually increased or decreased until the value reaches to the normal reference value corresponding to a desired address depending on whether a seek direction is the inner peripheral side or the outer peripheral side of the disk.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a CLV (Con
The present invention relates to an optical disk device of a constant linear velocity (constant linear velocity) type.

[0002]

2. Description of the Related Art In a CLV type optical disk apparatus, the relative linear velocity of a light spot on a track for recording and reproduction is kept constant over the entire area of the disk, and the CAV (CoV)
The recording capacity of the disc can be increased as compared with the nstant angular velocity (constant angular velocity) method.

Normally, in the CLV system, a target linear velocity value is set to a constant reference value, and the rotation speed of a spindle motor for driving a disk is inversely proportional to the radius of a track.
Control is performed so that the speed is faster on the inner circumference side of the disc and slower on the outer circumference side.

In this case, as shown in FIG. 8, the number of rotations of the disk becomes Nmax at the innermost circumference Pin of the disk, and decreases monotonically in the outer circumferential direction of the disk.
It becomes the smallest Nmin at t. For example, in the case of a compact disk having a diameter of 12 cm, the ratio between the maximum and minimum rotation speeds (Nmax / Nmin) is about 2.5 times. In this specification, "rotation speed" is used in the same meaning as "rotation speed".

[0005]

The conventional CL
In the V-type optical disk device, when the access near the innermost circumference and the vicinity of the outermost circumference are alternately repeated using the target linear velocity value as a reference value, as shown in FIG. 9, each period ts to ta;
Tc; td to te; tf to tg}, the rotation number of the disk repeats a change accompanied by rapid deceleration and acceleration between No near the innermost circumference and Ni near the outermost circumference. For example, in the case of the compact disk described above, the rotational speed of the disk is reduced to 40% (1 / 2.5) and then accelerated 2.5 times.

However, when such rapid acceleration / deceleration control is repeated, a large load is applied to the motor and the active element (driver IC) of the drive circuit due to the inertia (moment of inertia) of the spindle motor and the like, and large electric power is generated. There is a problem that it consumes and generates considerable heat. Also, there is a problem that sudden acceleration / deceleration easily induces unnecessary vibration and noise.

In order to solve such a problem, when the time during which data is not read from the disk continues for a predetermined time or more, the reference value of the CLV is switched to reduce the rotation speed of the disk to about half. -Low-vibration optical disk devices are known.

However, in the case where the rotation speed of the disk is reduced to about half, it is necessary to return the rotation speed of the disk to the rotation speed corresponding to the original reference value at the time of the next access, and then the access is not sufficiently performed. The problem arises that a high performance cannot be obtained.

It should be noted that it takes a certain amount of time to return the rotation speed of the disk to the rotation speed corresponding to the original reference value, so that there is a problem that the access time becomes longer.

On the other hand, most of the vibration and noise generated by the optical disk device depend on the rotation speed of the disk. Therefore, irrespective of the slow data transfer rate to the external computer, when data is read at a constant linear speed, the disk rotation speed is higher than necessary, causing unnecessary vibration and noise. There are cases.

In view of the foregoing, it is an object of the present invention to provide a CLV type optical disk device which is power-saving, has low vibration, and allows high-speed access.

[0012]

According to a first aspect of the present invention, there is provided an optical disk apparatus comprising: an optical head capable of moving in a radial direction of the optical disk so as to face the optical disk; A rotation control means for controlling the rotation speed of the motor so as to be a set target linear velocity value, and the target linear velocity value is reduced according to a situation with respect to a reference value. It is characterized in that target value control means for controlling so as to set to a predetermined value is provided.

In the optical disk apparatus according to the first aspect of the present invention, the target linear velocity value for controlling the rotation speed of the motor is set by the target value control means from an ordinary reference value.
The value is set to a predetermined value that is reduced according to the situation, and a rapid change in the rotation speed of the motor is avoided.

According to a second aspect of the present invention, in the optical disk apparatus according to the first aspect, when the optical head moves, the target value control means controls the rotational speed of the motor immediately after the movement. The linear velocity value at that time is set as a provisional target linear velocity value, and the provisional target linear velocity value is gradually increased or decreased to a reference value of the moving position.

In the optical disk device according to the second aspect of the present invention, at the time of random access, the linear velocity value at the rotation speed of the motor immediately after the movement of the optical head is set to the provisional target linear velocity value. Later, the rotational speed is gradually increased or decreased to a normal reference value, so that a sudden change in the rotational speed of the motor is avoided, and the acceleration amount when the rotational speed is increased next time is reduced.

According to a third aspect of the present invention, in the optical disk device of the first aspect, when the optical head is not reproducing recorded data, the target value control means may control an inner circumference of the optical disk. The target linear velocity value is set by multiplying the reference value by a larger reduction rate toward the side.

In the optical disk device according to the third aspect of the present invention, the target linear velocity value is changed in accordance with the position of the optical head, and when seeking to an arbitrary position on the disk, an extremely large change in the number of rotations is caused. Does not occur.

According to a fourth aspect of the present invention, in the optical disk device according to the first aspect, a buffer memory for temporarily storing reproduction data when the optical head reproduces recorded data; Data amount discriminating means for discriminating the amount of data to be transferred in the memory, wherein the target value control means sets the data amount in the buffer memory to a predetermined value based on the discrimination output of the data amount discriminating means. If not, the reference value is set to the target linear velocity value, and if the amount of data in the buffer memory is equal to or more than a predetermined value, the target linear velocity value is set by gradually decreasing from the reference value to a predetermined minimum value. It is characterized by doing so.

In the optical disk apparatus according to the present invention having the above construction, the target linear velocity value is maintained at a normal reference value or up to a predetermined minimum value according to the amount of data to be transferred in the buffer memory. It can be gradually reduced to correspond to the level of the data transfer rate to the outside.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an optical disk device according to the present invention will be described below with reference to FIGS.

[Structure of Embodiment] FIG. 1 shows the entire structure of an embodiment of the present invention, and FIG. 2 shows the structure of a main part thereof.

In FIG. 1, an optical disk 1 is provided so as to face an optical head 11 and is driven by a spindle motor 12, and the optical head 11 is moved in a radial direction of the disk 1 by a feed motor 13. You.

In order to know the rotational speed of the disk 1 and the approximate position of the optical head 11, frequency generators (FG) 14, 15 are mechanically connected to the spindle motor 12 and the feed motor 13, respectively.

The drive signal from the spindle servo circuit 20sp of the servo control circuit 20 is supplied to the motor drive circuit 16 for driving the spindle motor 12, and the drive motor 13 from the servo control circuit 20 is supplied to the feed motor 13. A signal is provided. Note that the spindle servo circuit 2
0sp will be described later in detail.

The reproduced RF signal from the optical head 11 is passed through the preamplifier circuit 31 of the data reproducing system 30 to be reproduced RF signal.
The signal is supplied to a signal processing circuit 32, and the output of the signal processing circuit 32 is used as a synchronous data generation / clock recovery circuit (PLL) 3
3, the synchronous data is generated, the clock is reproduced, and the reproduced clock PLCK is supplied to the spindle servo circuit 20sp.

On the other hand, the synchronous data is supplied to a data demodulation / error correction circuit 34, subjected to predetermined processing, and temporarily stored in a buffer memory 37 via a memory controller 35. Then, the reproduction data stored in the buffer memory 37 is appropriately read out by the memory controller 35 and passed through the interface circuit (I / F) 36.
It is derived outside and taken into a computer (not shown).

The system control circuit (CPU) 41 is connected to the reproduction RF signal processing circuit 32, the synchronous data generation / clock reproduction circuit 33, the data demodulation / error correction circuit 34, the memory controller 35, and the interface circuit 36, respectively. And performs system control of the entire apparatus.

A read command from the computer is supplied to the system control circuit 41 through the interface 42. The system control circuit 41 receives a command from the computer and executes control such as seeking and data reproduction (reading).

In this embodiment, the outputs of the frequency generators (FG) 14 and 15 are supplied to a system control circuit 41.
, Servo processing is performed in a time-division (interrupt) manner. Then, a frequency division ratio setting signal Sdv generated with reference to the frequency division ratio table 43 connected to the system control circuit 41 is supplied from the system control circuit 41 to the spindle servo circuit 20sp.

In FIG. 2, the spindle servo circuit 20
The reproduction clock PLCK supplied to the input terminal Tin of the sp
The signal is supplied to a second frequency dividing circuit 22 having a variable frequency dividing ratio through the first frequency dividing circuit 21. The second frequency dividing circuit 22 receives a frequency dividing ratio setting signal S from the system control circuit 41 (see FIG. 1).
dv is supplied to control the frequency division ratio.

The output signal of the second frequency dividing circuit 22 is supplied to a frequency detecting circuit 23 and converted into a voltage corresponding to the frequency. The voltage corresponding to the frequency is output through an adding circuit 28 and a low-pass filter 29. The signal is supplied to a terminal Tout and supplied to a drive circuit of the spindle motor 12, so that the spindle motor 12 is controlled (speed servo control) so as to have a rotation speed corresponding to the supplied voltage.

The output signal of the second frequency dividing circuit 22 is
The signal is supplied to the third frequency dividing circuit 24. And the frequency dividing circuit 2
4 is supplied to the phase comparison circuit 25, and the output of the reference clock generation circuit 26 is supplied to the phase comparison circuit 25 through the fourth frequency dividing circuit 27. The output of the phase comparison circuit 25 is combined with the output of the frequency detection circuit 23 in the addition circuit 28,
It is led to the output terminal Tout and is supplied to the drive circuit of the spindle motor 12, whereby the spindle motor 12 is phase-controlled.

By controlling the frequency dividing ratio of the second frequency dividing circuit 22 in this way, the spindle motor 12 can rotate at a rotational speed corresponding to the frequency dividing ratio and generate the reference clock from the reference clock generating circuit 26. It is controlled to rotate in phase synchronization. Here, the linear velocity of the disk is controlled by setting the frequency division ratio to a value such that the spindle motor 12 rotates at a rotational speed corresponding to the reference linear velocity according to the scanning position of the optical disk in the radial direction. .

For example, when the optical disk is a DVD, the frequency division ratio of the first, third and fourth frequency dividing circuits 21, 24, 27 is 1 / Na = 1/12 1 / Nb = 1/4 1 / Nr = 1/4608, and the repetition frequency fr of the reference clock of the generation circuit 26 is fr = 33.8688 MHz.

When the frequency dividing ratio of the variable frequency dividing circuit 22 is, for example, 1 / Nv = 1/75, the repetition frequency fp of the reproduction clock PLCK is
Is fp = 26.46 MHz.

[Rotation Control of the Embodiment] Next, the rotation control of the embodiment of the present invention will be described with reference to FIGS.

In general, in the CLV type optical disk apparatus, in the case of random access, immediately after a seek, the actual rotational speed of the disk and the reference rotational speed corresponding to a desired address on the disk are described above. There is a considerable difference due to the inertia of the spindle motor 12 and the like.

When seeking to the inner peripheral side of the disk, the rotational speed (and linear velocity) of the disk immediately after the seek becomes considerably smaller than the reference rotational number (and linear velocity), and conversely, to the outer peripheral side of the disk. When seeking, the rotation speed (and linear speed) of the disk immediately after the seek becomes considerably higher than the reference rotation speed (and linear speed).

In this embodiment, in the case of random access, a linear velocity control routine 100 as shown in FIG. 3 is executed.

In this routine 100, first, in steps 101 and 102, the end of the seek
If it is checked that the LL has been pulled, step 1
In step 03, the disk rotation speed immediately after the seek is measured, and in the next step 104, the ratio K between the measured value and the reference rotation speed corresponding to the desired address is calculated.

Then, the process proceeds to a step 105, wherein the calculation result K in the step 104 is multiplied by a reference linear velocity corresponding to a desired address (corresponding to a radial position of the optical disk), and the CLV immediately after the seek is performed. Is set. That is, the linear velocity corresponding to the disk rotation speed immediately after the seek is provisionally set as the target linear velocity value.

For example, when seeking to the inner circumferential side of the disk, if the actual rotation speed immediately after the seek is 0.7 times the rotation speed at that position corresponding to the reference linear velocity value,
The provisional target linear velocity value is also set to 0.7 times the reference linear velocity value.

Conversely, when seeking to the outer peripheral side of the disk, if the actual rotation speed immediately after the seek is 1.3 times the rotation speed at that position corresponding to the reference linear velocity value,
The provisional target linear velocity value is also set to 1.3 times the reference linear velocity value.

In the next step 106, the frequency division ratio corresponding to the provisional target linear velocity value is selected with reference to the frequency division ratio table 43.

The selected dividing ratio is gradually increased or decreased until the reference dividing ratio corresponding to the reference linear velocity value is reached (steps 107 and 108). , Is gradually accelerated or decelerated to 1.0 times the reference value.

The measurement of the number of revolutions of the disk is executed by the system control circuit (CPU) 41 based on the output of the frequency generator 14 coupled to the spindle motor 12. The outline and fine position information of the optical head 11 is transmitted to a frequency generator 15 coupled to the feed motor 13.
And the reproduced RF signal processing circuit 32.

In this embodiment, when the access near the innermost circumference and the vicinity of the outermost circumference of the disk are alternately repeated, FIG.
As shown in A and B, each period ts to t1; t2 to t3;
From t4 to t5; from t6 to t7}, the rotation speed of the disk repeats a change accompanied by slower deceleration and acceleration than in the conventional example.

In particular, in the first period ts to t1, the deceleration is slower than in the first period ts to ta shown in FIG. 9 described in the conventional example, and accordingly, the period t in FIG.
The time is longer than s to ta.

FIG. 4A shows the case where the pull-in range of the PLL is not so large, and when the pull-in range of the PLL is wide, the change in the rotation speed can be made smaller as shown in FIG. 4B. .

As described above, in this embodiment,
The actual linear velocity immediately after the seek is set to the target linear velocity value, and thereafter, the set target linear velocity value is changed so as to approach the reference linear velocity value, thereby avoiding a rapid change in the rotational speed. In the event that it is necessary to increase the linear velocity, the amount of acceleration can be reduced,
The load on the motor and drive circuit can be reduced,
Vibration and noise can also be reduced.

By the way, as set above,
When the target linear velocity value immediately after the seek is close to the reference value, the amount of the change is affected by the state of data transfer to the outside and the like, and therefore should not necessarily be constant. Therefore, in this embodiment, the linear velocity setting routine 2 shown in FIG.
00 sets the target linear velocity corresponding to the data transfer status and the like.

That is, when the linear velocity setting routine 200 shown in FIG. 5 starts, in the first step 201, it is determined whether or not data is being read. If the data has not been read, the process proceeds to step 202, in which a target linear velocity value for the next access is set by multiplying the reference linear velocity value by a predetermined reduction rate that increases toward the inner circumference side.

That is, since the rotation speed corresponding to the reference linear velocity value is low on the outer circumference side and high on the inner circumference side, if the reduction rate is the same, the rotation speed becomes too low on the outer circumference side and the next access becomes slow. To prevent them from

In the next step 203, the frequency division ratio corresponding to the reduced target linear velocity is selected with reference to the frequency division ratio table 43. Then, the process returns to step 201.

When data is not read out by the above-described target linear velocity setting processing, the chain line L shown in FIG.
The target rotation speed is set by multiplying the reference rotation speed indicated by rr by a larger reduction rate toward the inner circumferential side, as indicated by a polygonal line Lrc in FIG.

As is clear from FIG. 6, the target rotation speed Na on the innermost circumference is set to be considerably smaller than the reference rotation speed Nmax, while the target rotation speed Nb on the outer circumference is smaller than the reference rotation speed at the position Pb. Set close.

In this way, by changing the set value of the target linear velocity according to the position of the optical head, when seeking to an arbitrary position on the disk, the rotation speed does not change so much.

For example, when the optical head is on the inner peripheral side, by setting a target linear velocity which is considerably slower, when seeking to the outer peripheral side, it is not necessary to reduce the speed so much.
The load on the motor and the drive circuit can be reduced.

On the other hand, when the optical head is located on the outer peripheral side, by setting a target linear velocity value that is not so different from the reference value, the rotational speed of the disk becomes too low, and the next access becomes slow. Can be avoided.

On the other hand, if the data is read out in step 201, the process proceeds to step 211, where the amount of data in the buffer memory 37 is measured, and the next step 212
Then, it is determined whether the data amount in the buffer memory 37 is less than a predetermined amount.

If the data transfer rate to the outside is high and the amount of data in the buffer memory 37 is less than the predetermined amount, the process proceeds to step 213, where the target linear velocity value is set so as to hold the reference linear velocity value. You. In the next step 214, the frequency division ratio corresponding to the reference linear velocity value is selected with reference to the frequency division ratio table 43.

If the data transfer rate to the outside is not so fast and the data amount in the buffer memory 37 exceeds a predetermined amount in step 212, step 2
The program proceeds to 15 where the target linear velocity value is set so as to gradually decrease. In the next step 216, the frequency division ratio corresponding to the gradually reduced target linear velocity value is selected with reference to the frequency division ratio table 43, and the process returns to step 201.

In step 217, it is determined whether or not the gradually decreased target linear velocity value has decreased to a predetermined minimum linear velocity depending on the data transfer rate and the capacity of the buffer memory.

If the target linear velocity value has not decreased to the minimum linear velocity, the process returns to step 212, and the processing of steps 215 to 217 is repeated until the target linear velocity value reaches the minimum linear velocity. When the target linear velocity value reaches the minimum linear velocity, the process returns to step 201.

If the amount of data in the buffer memory 35 becomes smaller than the predetermined amount during the process of gradually reducing the target linear velocity value, the process proceeds from step 212 to step 213, where the target linear velocity value is set to the reference value. Set to the linear velocity value.

If the data amount in the buffer memory 35 is less than the predetermined amount by the above-described target linear velocity value setting processing, as shown by a chain line Lvr in FIG.
nm is retained.

As shown by the broken line Lvc in FIG.
From time tma when the amount of data in the buffer memory 35 reaches a predetermined amount, the target linear velocity value is reduced, and at time tmb,
After decreasing to the predetermined minimum linear velocity Vrd, this linear velocity Vrd is maintained.

As described above, by controlling the target linear velocity value according to the amount of data in the buffer memory, the performance of the optical disk device is not reduced when the data transfer rate to the outside is high. Conversely, even when the data transfer rate to the outside is low, it is possible to prevent the memory from overflowing and to avoid the generation of unnecessary vibration and noise due to higher-speed rotation than necessary.

[0069]

As described above, according to the first aspect of the present invention, it is possible to avoid a sudden change in the rotation speed of the motor in accordance with the operation state of the apparatus, and reduce the load on the motor and the drive circuit. In addition, vibration and noise can be reduced.

According to the second aspect of the present invention, it is possible to avoid an abrupt change in the number of revolutions at the time of random access, and to reduce the acceleration amount even when it becomes necessary to increase the linear velocity next time. The load on the motor and the drive circuit can be reduced, and the vibration and noise can be reduced.

According to the third aspect of the present invention, when seeking to an arbitrary position on the disk, the rotation speed does not change much. It is also possible to avoid a delay in the next access.

Further, according to the invention of claim 4, when the data transfer rate to the outside is high, the performance of the optical disk device is not degraded, and when the data transfer rate to the outside is low, In addition, it is possible to prevent the memory from overflowing, and to avoid the occurrence of unnecessary vibration and noise due to excessively high speed rotation.

[Brief description of the drawings]

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

FIG. 2 is a block diagram showing a configuration of a main part of the embodiment of the optical disk device according to the present invention.

FIG. 3 is a flowchart for explaining rotation speed control according to the embodiment of the present invention;

FIG. 4 is a time chart illustrating rotation speed control according to the embodiment of the present invention.

FIG. 5 is a flowchart for explaining rotation speed control according to the embodiment of the present invention.

FIG. 6 is a conceptual diagram illustrating rotation speed control according to the embodiment of the present invention.

FIG. 7 is a conceptual diagram illustrating rotation speed control according to the embodiment of the present invention.

FIG. 8 is a conceptual diagram for explaining the present invention.

FIG. 9 is a time chart for explaining rotation speed control of a conventional example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Optical disk, 11 ... Optical head, 12 ... Spindle motor, 13 ... Feed motor, 14, 15 ... Frequency generator (FG), 16 ... Spindle motor drive circuit, 20 ... Servo control circuit, 20sp ... Spindle servo circuit, 21
... frequency divider circuit, 22 ... variable frequency divider circuit, 23 ... frequency detection circuit, 24 ... frequency divider circuit, 25 ... phase comparator circuit, 26 ... reference clock generation circuit, 27 ... frequency divider circuit, 30 ... data reproduction system, 32 ... Reproduction RF signal processing circuit, 33 ... Synchronous data generation / clock reproduction circuit (PLL), 34 ... Data demodulation
Error correction circuit, 35: memory controller, 36: interface circuit (I / F), 37: buffer memory,
41: system control circuit (CPU), 42: bus, 43
... frequency division ratio table, 100 ... linear velocity control routine, 20
0: linear velocity setting routine, PLCK: reproduction clock, Sdv ...
Division ratio setting signal

Claims (4)

[Claims] An optical head capable of moving in a radial direction of the optical disk so as to face the optical disk; a motor for rotating the optical disk; and rotating the motor to achieve a set target linear velocity value. Rotation control means for controlling a speed; and target value control means for controlling the target linear velocity value to be set to a predetermined value reduced according to a situation with respect to a reference value. Optical disk device. 2. The optical disk device according to claim 1, wherein said target value control means calculates a linear target value at a rotational speed of said motor immediately after said optical head is moved. An optical disk device, wherein the provisional target linear velocity value is gradually increased or decreased to a reference value of a movement position while being set to a value. 3. The optical disk device according to claim 1, wherein the target value control means sets a larger reduction rate toward the inner circumference of the optical disk as the reference value when the optical head is not reproducing recorded data. An optical disk device wherein the target linear velocity value is set by multiplying the target linear velocity value. 4. The optical disk device according to claim 1, wherein a buffer memory for temporarily storing reproduction data when the optical head reproduces the recording data; and a data amount to be transferred in the buffer memory. Data amount determining means for determining whether the data amount in the buffer memory is less than a predetermined value based on the determination output of the data amount determining means. An optical disc device, wherein the target linear velocity value is set by setting the linear velocity value, and when the data amount in the buffer memory is equal to or more than a predetermined value, the target linear velocity value is gradually reduced from the reference value to a predetermined minimum value. .