JP2002133672A - Disc device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To conduct a stable seek action regardless of the change of the amount of load. SOLUTION: A magnetic optical disc 44 in which a track is formed on a recording side, is attached to a spindle 46 and TE signal detecting circuit 26 detects a tracking error signal based on laser light reflected from the recording side when an optical pickup 12 irradiates the recording side with the laser light. The controlling electric pressure of a sled motor 42 is increased by DSP 36 when the optical pickup 12 is moved in the radial direction of the magnetic optical disc 44 by the sled motor 42 and the cycle of the tracking error signal is longer than a threshold, while the controlling electric pressure of the thread motor 42 is set to an initial value by DSP 36 when the cycle of the tracking error signal is equal to or shorter than the threshold.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disk drive, and more particularly to a disk drive for moving an optical pickup in a radial direction of a disk recording medium for a seek operation.

[0002]

2. Description of the Related Art In a disk drive, in order to move an optical pickup in a radial direction of a disk recording medium for a seek operation, it is necessary to rotate a thread motor. For this reason, in the related art, a sled control voltage is output at the time of seek and the sled motor is rotated in a predetermined direction.

[0003]

However, in the prior art, since the sled control voltage is always set to a predetermined value, the sled motor may not be able to rotate properly when the load changes. For example, at low temperatures, the viscosity of the lubricating oil increases, and an excessive load is applied to the thread motor. At this time, if it is attempted to drive the sled motor at the same voltage as at normal temperature, there is a possibility that the rotation speed of the sled motor is reduced or, in the worst case, the rotation is stopped. Here, if the sled control voltage is always set higher, the sled motor rotates even when overloaded, but the noise during the seek operation increases.

Therefore, a main object of the present invention is to provide a disk drive capable of performing a stable seek operation irrespective of a change in a load amount.

[0005]

According to a first aspect of the present invention, there is provided a mounting means for mounting a disk recording medium having tracks formed on a recording surface, an optical pickup for irradiating a recording surface with a laser beam, and an optical pickup having a diameter of the recording surface. Motor for moving in the direction, detecting means for detecting a tracking error signal based on the laser light reflected from the recording surface, raising means for raising the control voltage of the motor when the period of the tracking error signal is longer than a threshold value, and tracking error A disk device comprising a setting means for setting a control voltage of a motor to a predetermined value when a period of a signal is equal to or shorter than a threshold value.

According to a second aspect of the present invention, there is provided an optical pickup for irradiating a recording surface of a disk recording medium with laser light, a motor for moving the optical pickup in a radial direction of the recording surface, a detecting means for detecting a peripheral temperature of the motor, First determining means for determining the first voltage as the control voltage of the motor when the temperature is higher than the threshold value, and second determining means for determining the second voltage higher than the first voltage as the control voltage of the motor when the ambient temperature is lower than the threshold value A disk device comprising:

[0007]

In the first invention, when a disk recording medium having tracks formed on a recording surface is mounted by mounting means and the optical pickup irradiates the recording surface with laser light,
A tracking error signal is detected by the first detection means based on the laser light reflected from the recording surface. When the optical pickup is moved in the radial direction of the recording surface by the motor, if the period of the tracking error signal is longer than the threshold, the control voltage of the motor is increased by the increasing means. On the other hand, if the period of the tracking error signal is equal to or shorter than the threshold, the control voltage of the motor is set to a predetermined value by the setting means.

Therefore, when the period of the tracking error signal is longer than the threshold value because the rotation speed of the motor is low, the control voltage of the motor increases and the rotation speed is accelerated. When the period of the tracking error signal becomes equal to or shorter than the threshold value by increasing the rotation speed, the control voltage of the motor is set to a predetermined value. By setting the predetermined value, the rotation speed of the motor decreases, and when the period of the tracking error signal becomes longer than the threshold value, the rotation speed of the motor is accelerated again.

Preferably, the increasing means increases the control voltage by adding a voltage value related to an error between the cycle of the tracking error signal and the threshold to a predetermined value.

The peripheral temperature of the motor may be detected by the second detecting means, and the predetermined value may be changed according to the detected peripheral temperature.

In the second invention, an optical pickup for irradiating a recording surface of a disk recording medium with laser light is moved in a radial direction of the recording surface by a motor. The surrounding temperature of the motor is detected by the detecting means, and if the detected surrounding temperature is higher than the threshold value, the first determining means determines the first voltage as the control voltage of the motor. On the other hand, if the detected ambient temperature is equal to or lower than the threshold, the second determining means determines a second voltage higher than the first voltage as the control voltage of the motor.
That is, when the ambient temperature is low and the motor is overloaded, the motor is driven by the second voltage higher than the first voltage.

[0012]

According to the first aspect, when the rotation speed of the motor is low, the control voltage of the motor is increased to increase the rotation speed, and the period of the tracking error signal becomes equal to the threshold value due to the increase in the rotation speed. Alternatively, when the value is shorter than the threshold value, the control voltage of the motor is set to a predetermined value, so that a stable seek operation can be performed irrespective of a change in the load amount.

According to the second aspect, when the ambient temperature is low and the motor is overloaded, the second voltage higher than the first voltage is used as the motor control voltage.
A stable seek operation can be performed regardless of a change in the load amount.

The above objects, other objects, features and advantages of the present invention will become more apparent from the following detailed description of embodiments with reference to the drawings.

[0015]

Referring to FIG. 1, an optical disk device 10 of this embodiment includes an optical pickup 12 provided with an optical lens 14. The optical lens 14 is supported by the tracking actuator 16 and the focus actuator 18, and the laser light emitted from the laser diode 20 is converged by such an optical lens 14 and is
The light is irradiated onto the recording surface of a magneto-optical disk 44 such as O (Advanced Storage Magneto Optical disc). As a result, a desired signal is recorded on or reproduced from the magneto-optical disk 44.

The magneto-optical disk 44 is mounted on a spindle 46 and is rotated by a spindle motor 48.
The magneto-optical disk 44 is a ZCLV (Zone Constant Linear).
This is a Velocity type disc, and the number of rotations decreases as the optical pickup 12 moves from the inner circumference to the outer circumference.

Light reflected from the recording surface passes through the same optical lens and irradiates the photodetector 22. The output of the photodetector 22 is supplied to the FE signal detection circuit 24 and the TE signal detection circuit 2.
6 and the FE (Focus Error) signal and TE (T
racking Error) signals are detected separately. The detected FE signal and TE signal are sent to the DSP (Digital Signal Process) via A / D converters 34a and 34b.
or) 36 respectively.

The DSP 42 executes focus servo processing based on the FE signal, and executes tracking servo processing and thread servo processing based on the TE signal.
A focus actuator control voltage is generated by the focus servo processing, and the focus actuator control voltage is output to the focus actuator 18 via the D / A converter 44b. A tracking actuator control voltage is generated by the tracking servo process, and the tracking actuator control voltage is output from the D / A converter 44a to the tracking actuator 16. The position of the optical lens 14 in the optical axis direction is controlled by a focus actuator control voltage, and the position of the optical lens 14 in the radial direction is controlled by a tracking actuator control voltage. The DSP 42 further generates a thread control voltage by a thread servo process,
The pulse width of the PWM signal output from the M signal generation circuit 46 changes according to the thread control voltage. The rotation speed and the rotation direction of the thread motor 42 are such PW
Controlled by the M signal.

The TE signal is also compared with a predetermined threshold value by a comparator 28, and the TZC (Track
ng Zero Cross) signal is output. Optical pickup 1
2 moves in the radial direction of the magneto-optical disk 44 for seeking, the TE signal changes as shown in FIG.
The TZC signal changes as shown in FIG. That is, the TZC signal rises at the zero level in the course of the TE signal changing from the negative level to the positive level,
The signal E falls at the zero level in the course of changing from the plus level to the minus level. Such a TZC signal output from the comparator 28 is provided to the ZC counter 30 and the cycle measuring circuit 32. ZC counter 30
Counts the rise of the TZC signal, and the cycle measuring circuit 32 measures the cycle of the TZC signal. ZC counter 30
And the measurement period by the period measurement circuit 32 are directly supplied to the DSP 36.

During a seek operation, the DSP 36 drives the thread motor 42 to move the optical pickup 12 in the radial direction of the magneto-optical disk 44. The sled control voltage at this time is determined based on the output of the temperature sensor 50 installed around the optical pickup 12 and the measurement cycle of the cycle measurement circuit 32. The temperature detected by the temperature sensor 50 corresponds to the temperature of the thread motor 42. The DSP 36 sets the initial value of the thread control voltage to a standard seek voltage (normal temperature seek voltage) if the detected temperature is higher than a predetermined threshold, and sets the initial value of the thread control voltage to the standard seek voltage if the detected temperature is lower than the predetermined threshold. Low temperature seek voltage (> Standard seek voltage)
Set to. The DSP 36 also performs the TZC during the seek operation.
If the cycle of the signal is equal to or less than the predetermined threshold, the thread control voltage is maintained at the initial value. If the cycle is longer than the predetermined threshold, the set thread control voltage is set higher than the initial value.

At low temperatures, the viscosity of the lubricating oil increases and the load on the sled motor 42 increases, so that the sled motor 42 may not rotate at an appropriate speed with the sled control voltage at normal temperature. On the other hand, if the thread control voltage at normal temperature is set higher, the noise during the seek operation increases. Therefore, in this embodiment, if the temperature detected by the temperature sensor 50 is equal to or lower than a predetermined threshold, a low-temperature seek control voltage higher than the standard seek voltage is set as the initial value, and the rotation of the thread motor 42 during the seek is further performed. When the speed is low, the seek control voltage is increased from the initial value. This allows the sled motor 42 to rotate at an appropriate speed even when performing a seek at a low temperature. Further, the standard seek control voltage can be set lower, and noise during a seek operation at room temperature can be suppressed.

The photodetector 22, the FE signal detection circuit 24 and the TE signal detection circuit 26 are configured as shown in FIG. The photodetector 22 includes four detection elements 22a to 22d. Outputs of the detection elements 22a to 22d are subjected to different calculations in an FE signal detection circuit 24 and a TE signal detection circuit 26. Specifically, the FE signal detection circuit 24
, And the TE signal detection circuit 26 calculates Equation 2.

[0023]

FE = (A + C)-(B + D)

[0024]

## EQU2 ## TE = (A + D)-(B + C) where "A" to "D" in Equations 1 to 3 are respectively
It corresponds to the output of the detection elements 22a to 22d. The detection elements 22a and 22d detect the left half light component of the laser light in the trace direction, and the detection elements 22b and 22c detect the right half light component of the laser light in the trace direction.

The DSP 36 controls the seek operation according to the flowchart shown in FIG. Note that the DSP 36 is actually formed by a logic circuit, but for convenience of description, a flowchart is used.

First, in step S1, the tracking servo is stopped, and in step S3, the peripheral temperature data of the sled motor 42 detected by the temperature sensor 50 is fetched.
In step S5, the acquired ambient temperature data is compared with a predetermined threshold. If ambient temperature> threshold, a standard seek voltage is set as an initial value in step S7. If ambient temperature ≦ threshold, a low temperature is set in step S9. Set the seek voltage as the initial value. When the processing in step S7 or S9 is completed, the ZC counter 30 is reset in step S11, and a thread control voltage having the initial value set in step S7 or S9 is output. The thread motor 42 is
The ZC counter 30 rotates in response to the PWM signal based on the sled control voltage, and is incremented in response to the rise of the TZC signal output from the comparator 28.

In step S15, it is determined whether or not the count value of the ZC counter 30 has reached "target value-1".
If NO, the cycle of the TZC signal (Z
C cycle). That is, the measurement cycle by the cycle measurement circuit 32 is taken. In step S19, the detected Z
The C cycle is compared with a predetermined threshold, and the thread control voltage is updated in step S21 or S23 according to the comparison result. That is, if ZC cycle> predetermined threshold, the thread control voltage is corrected according to Equation 3, and if ZC cycle ≦ predetermined threshold, the thread control voltage is set to the initial value in step S23.

[0028]

## EQU3 ## When the processing in step S21 or S23 is completed, the updated thread control voltage is output in step S25, and the process returns to step S15.

Therefore, if the rotation speed of the sled motor 42 is lower than the predetermined speed, the sled control voltage increases, and the sled motor 4
When the rotation speed of No. 2 becomes equal to or higher than the predetermined speed, the sled control voltage is returned to the initial value (standard seek voltage or low-temperature seek voltage).

When the count value of the ZC counter 30 reaches "target value-1", steps S15 to S27 are performed.
To apply a brake to the sled motor 42. Specifically, it outputs a thread control voltage of the opposite polarity. When the rotation of the thread motor 42 stops, the tracking servo is executed in step S29, and the process returns.

As can be understood from the above description, the ambient temperature of the sled motor 42 is detected by the temperature sensor 50. If the detected ambient temperature is higher than the threshold, the standard seek voltage is set to the initial value of the control voltage of the sled motor 42. Determined as a value. On the other hand, if the detected ambient temperature is equal to or lower than the threshold, a low-temperature seek voltage higher than the standard seek voltage is determined as the initial value of the control voltage of the sled motor 42. Therefore, when the ambient temperature is low and the sled motor 42 is overloaded, the sled motor 42 is driven by the seek voltage.

When the optical pickup 12 is moved in the radial direction of the magneto-optical disk 44 by the thread motor 42, if the period of the tracking error signal is longer than a threshold value, the control voltage of the thread motor 42 is increased. On the other hand, if the cycle of the tracking error signal is equal to or shorter than the threshold, the control voltage of the sled motor 42 is set to the initial value.

Therefore, when the period of the tracking error signal is longer than the threshold value because the rotation speed of the sled motor 42 is low, the control voltage of the sled motor 42 increases and the rotation speed is accelerated. When the cycle of the tracking error signal becomes equal to or shorter than the threshold value due to an increase in the rotation speed, the control voltage of the thread motor 42 is returned to the initial value. When the rotation speed of the sled motor 42 is reduced by returning to the initial value, and the period of the tracking error signal becomes longer than the threshold value, the rotation speed of the sled motor 42 is increased again. By adjusting the control voltage of the sled motor 42 in this manner, a stable seek operation can be performed regardless of a change in the load amount.

In this embodiment, each time the period of the TE signal is detected once, the period is compared with a threshold value to adjust the thread control voltage. Alternatively, the thread control voltage may be adjusted by comparing the detected average value of a plurality of cycles with a threshold value.

In this embodiment, a magneto-optical disk such as an ASMO is used as a disk recording medium. However, it goes without saying that the present invention can be applied to a disk device for recording / reproducing a CD-ROM or a DVD. .

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention.

FIG. 2A is a waveform chart showing a tracking error signal, and FIG. 2B is a waveform chart showing a TZC signal.

FIG. 3 is a circuit diagram showing a photodetector, a TE signal detection circuit, and an FE signal detection circuit.

FIG. 4 is a flowchart showing a part of a DSP process during a seek operation;

FIG. 5 is a flowchart showing another part of the processing of the DSP during the seek operation.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Optical disk apparatus 12 ... Optical pick-up 26 ... TE signal detection circuit 30 ... ZC counter 32 ... Period measurement circuit 36 ... DSP 42 ... Thread motor 50 ... Temperature sensor

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Hiroshi Nakajima 2-5-5 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. F-term (reference) 5D088 MM08 5D117 AA02 BB00 CC06 EE07 EE22 FF12 FF27

Claims (4)

[Claims] 1. A mounting means for mounting a disk recording medium having tracks formed on a recording surface, an optical pickup for irradiating the recording surface with laser light, a motor for moving the optical pickup in a radial direction of the recording surface, First detecting means for detecting a tracking error signal based on the laser light reflected from a recording surface; increasing means for increasing a control voltage of the motor when a period of the tracking error signal is longer than a threshold value; A disk device, comprising: setting means for setting the control voltage of the motor to a predetermined value when the period of the signal is equal to or shorter than the threshold. 2. The apparatus according to claim 1, wherein said increasing means adds a voltage value related to an error between said period and said threshold value to said predetermined value.
The disk device as described above. 3. The disk device according to claim 1, further comprising a second detection unit configured to detect an ambient temperature of the motor, wherein the predetermined value differs according to the ambient temperature. An optical pickup for irradiating the recording surface of the disk recording medium with a laser beam; a motor for moving the optical pickup in a radial direction of the recording surface; a detecting means for detecting an ambient temperature of the motor; First determining means for determining a first voltage as a control voltage of the motor when the temperature is higher than a threshold, and a second voltage higher than the first voltage as the control voltage of the motor when the ambient temperature is equal to or lower than the threshold. A disk device comprising a second determining means for determining.