JP2002298389A - Vibration detector and optical disk device having the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vibration detector capable of detecting vibration of an optical disk device without using other sensor such as a vibration sensor and not to inhibit cost reduction and miniaturization of the device and the optical disk having the vibration detector. SOLUTION: When the optical disk device 1 is vibrated in accordance with rotation of a disk 2, the vibration of the optical disk 1 is detected by detecting induced electromotive force to be generated from coils of an actuator and a motor provided inside the optical disk drive such as a coil 24 for focusing servo provided in an optical pickup 20. The cost reduction and the miniaturization of the device are enabled since necessity of elements such as the vibration sensor used for the conventional optical disk device is eliminated by using such structure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk device for writing and / or reading data from and to an optical disk and a vibration detecting device used for the optical disk device.

[0002]

2. Description of the Related Art An optical disk may vibrate greatly when a defective optical disk having eccentricity or deformation is driven to rotate, or when an optical disk is clamped abnormally.

When the degree of such vibration exceeds the range of vibration that can be corrected by the optical pickup of the optical disk device, writing and reading on the optical disk become impossible. Further, when the vibration further increases, the rotating optical disk separates from the clamper and becomes jammed in the optical disk device, or a failure occurs in a drive device such as a motor provided in the optical disk drive device. .

For this reason, conventionally, a vibration detecting device 30 as shown in FIG. 4 is provided inside an optical disk device.

The vibration detecting device 30 includes a vibration sensor 31 using a solid sensor such as a strain sensor and an impact sensor, a detection circuit 32 for detecting an induced electromotive force from the vibration sensor 31, and a detection circuit 32. The microcomputer 33 controls a drive device of the optical disk based on the detected signal.

When the vibration sensor 31 detects a vibration larger than a normal minute vibration, the rotation of the optical disk is stopped by the control of the microcomputer 33 so that the above-described trouble does not occur. Is configured.

[0007]

However, since the above-described conventional vibration detecting device 30 uses the vibration sensor 31 for detecting vibration, the cost of the vibration sensor 31 is increased, and the vibration in the optical disk device 3 is increased. A space for installing the sensor 31 is required, which hinders cost reduction and reduction in size and size of the optical disk device.

SUMMARY OF THE INVENTION In view of the above problems, the present invention can detect the vibration of an optical disk device without using another sensor such as a vibration sensor. It is an object of the present invention to provide a vibration detecting device having no vibration detecting device and an optical disk device having the vibration detecting device.

[0009]

This and other objects are achieved by the present invention which is defined below as (1) to (9).

(1) A vibration detecting device used in an optical disk device comprising an optical disk driving means for driving an optical disk to rotate and an optical pickup for writing and / or reading data from and to the optical disk, wherein the vibration detecting device is Detecting means for detecting an induced electromotive force generated from at least one drive means inside the optical disk apparatus except for the optical disk drive means by vibration of the optical disk apparatus, based on the induced electromotive force detected by the detection means A vibration detecting device for detecting vibration by using a vibration detecting device.

(2) The detecting means detects the induced electromotive force when the optical disk is rotationally driven and the driving means for detecting the induced electromotive force is not driven. Vibration detection device.

(3) The vibration detecting device according to (1) or (2), wherein the detecting means detects an induced electromotive force generated from a coil of an actuator for driving an objective lens of the optical pickup.

(4) The detecting means comprises a motor coil serving as a driving means for displacing a pickup base on which an objective lens of the optical pickup and an actuator for driving the objective lens are mounted in a radial direction of the optical disk. The vibration detecting device according to the above (1) or (2), wherein the induced electromotive force is detected.

(5) The vibration detecting device according to any one of (1) to (4), wherein the detecting means includes a frequency detecting circuit for detecting a frequency of the induced electromotive force from the coil.

(6) The vibration detecting device according to the above (5), wherein the frequency to be detected is a frequency corresponding to the rotation speed of the optical disk.

(7) The vibration detecting device according to the above (5) or (6), wherein the frequency detecting circuit is a band pass filter.

(8) The detecting means detects the vibration of the optical disk device during a period from the start of the rotation driving of the optical disk to the start of the writing or reading of the optical disk by the pickup. The vibration detecting device according to any one of the above.

(9) An optical disk device comprising the vibration detecting device according to any one of (1) to (8).

Other objects, functions and effects of the present invention will become more apparent from the following description of embodiments with reference to the drawings.

[0020]

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

First, an optical disk device according to the present invention will be described. FIG. 1 is a block diagram showing the overall configuration of the optical disk device of the present invention.

The optical disk device 1 of the present invention is a
An optical disk device for writing and reading data to and from an optical disk (optical recording medium) represented by D, MO (magneto-optical disk), DVD, etc., as shown in FIG. It has a motor 11, a control unit 12 for controlling rotation of the motor 11 and movement of an optical pickup 20, which will be described later, and an optical pickup 20 for writing (recording) and reading (reproducing) information on the optical disk 2. are doing.

The motor 11 is provided with a turntable 18 and the like for mounting the optical disk 2 as in the conventional optical disk device. The motor 1
1 is connected to a power supply (not shown) and a control unit 12 for controlling the rotation of the motor 11.

FIG. 2 is a perspective view of a main part of the optical pickup 20 according to the optical disc apparatus 1 of the present invention.

As shown in FIG. 2, the optical pickup 20 directs a beam from a laser diode (not shown) to a predetermined position on the recording surface of the optical disk 2 as in the optical pickup used in the conventional optical disk apparatus. An objective lens 21 for condensing light, a lens holder 22 for supporting the objective lens 21, and a damper base 23 for swingably supporting the lens holder 22 are provided.

The lens holder 22 has a servo 24 for moving the lens holder 22 in the thickness direction of the optical disk 2 (the optical axis direction of the objective lens 21), that is, a focusing servo coil 24 for performing a focusing servo.
And a servo for moving the lens holder 22 in a direction parallel to the recording surface of the optical disc 2 (radial direction of the optical disc 2), that is, a tracking servo coil 25 for performing tracking servo, and at predetermined intervals from these coils. A magnet (not shown) provided on the damper base 23 is provided.

As shown in FIG. 2, the lens holder 22 records the optical disk 2 in the thickness direction (focusing direction) and the optical disk 2 via two suspension springs 26 provided vertically. It is supported by the damper base 23 so as to swing in a direction (tracking direction) parallel to the surface.

Hereinafter, a vibration detecting device according to the optical disk device of the present embodiment will be described. As shown in FIG. 1, the vibration detecting device 10 of the present embodiment includes the focusing servo coil 24, a vibration detecting circuit 13 for detecting an induced electromotive force generated in the focusing servo coil 24, And a control unit 12 for controlling the motor 11 based on a detection result from the detection circuit 13.

The Focusing Servo Coil 24
Is connected to a drive circuit (not shown) used for driving the focusing servo coil 24 and a vibration detection circuit 13 for detecting vibration of the optical disk device 1 when the optical disk 2 rotates. And constitutes a part of the vibration detection device 10 of the optical disk device 1.

Here, the vibration detecting device 10 uses the induced electromotive force generated in the focusing servo coil 24 by a change in magnetic flux from the magnet (not shown) penetrating the focusing servo coil 24. The vibration is detected based on the vibration. That is, the vibration is detected by measuring the value of the potential difference between two poles (between both terminals) of the focusing servo coil 24 by the vibration detection circuit 13 connected to the focusing servo coil 24. You.

The change in the magnetic flux changes the relative positional relationship between the damper base 23 and the lens holder 22 swingably supported by the damper base 23 due to the vibration of the optical disk device 1. This is caused by a change in the relative positional relationship between the magnet provided on the damper base 23 and the focusing servo coil 24 provided on the lens holder 22.

As shown in FIG. 1, the vibration detecting circuit 13 includes an amplifier 14 for amplifying an induced electromotive force from the focusing servo coil 24, and a signal of a frequency from the amplifier 14 having a predetermined value or a predetermined range. And a comparator circuit 16 for binarizing the signal output from the band-pass filter 15 at a predetermined threshold value. And a latch circuit 17 that holds the peak value of the signal from the comparator circuit 16 and sends it to the control unit 12.

The band-pass filter 15 detects the frequency of the induced electromotive force from the amplifier 14, and sends the signal to a comparator circuit 16 described later only when the frequency of the induced electromotive force is a predetermined value or a value within a predetermined range. It is provided to output a signal to prevent noise at the time of vibration detection and to improve detection accuracy.

That is, the frequency of the vibration of the optical disk device 1 generated by rotating the optical disk 2 in which eccentricity or deformation has occurred becomes a substantially constant value corresponding to the rotation speed of the optical disk 2. Therefore, the frequency of the induced electromotive force from the focusing servo coil 24 generated by this vibration also becomes a constant value depending on the rotation speed of the optical disc 2, and only the signal of the frequency within the predetermined range is defined. By performing detection using the bandpass filter 15, noise during vibration detection can be prevented, and erroneous detection of vibration can be prevented.

The operation of the vibration detecting circuit 13 will be described below. When an induced electromotive force is generated in the focusing servo coil 24 due to the vibration of the optical disc apparatus 1, the electromotive force is amplified by the amplifier 14 to a value detectable by the bandpass filter 15 and transmitted to the bandpass filter 15. You.

When the induced electromotive force from the amplifier 14 is input to the bandpass filter 15, the bandpass filter 15 detects the frequency of the induced electromotive force, and the frequency is used as the rotation speed of the optical disk device 1. And outputs a signal to the comparator circuit 16 only when the value is a predetermined value or a value within a predetermined range.

When a signal from the band pass filter 15 is input to the comparator circuit 16, the comparator circuit 16 binarizes the signal at a predetermined threshold and sends it to the latch circuit 17. I do.

When a signal from the comparator circuit 16 is input to the latch circuit 17, the latch circuit 17
Holds the peak value of the signal from the comparator circuit 16 and sends it to, for example, a port of a CPU of the control unit 12.

The amplifier 14 need not be provided if the induced electromotive force from the focusing servo coil 24 is sufficiently large to be detected by the vibration detection circuit 13. Also, it is possible to select whether or not to install the latch circuit 17 as needed.

Hereinafter, the operation of the vibration detecting device 10 according to the present embodiment will be described. Vibration detection device 10 of the present embodiment
Detects the vibration of the optical disc apparatus 1 when the optical disc 2 is rotating and the focusing servo coil 24 is not driven, that is, when the focusing servo coil 24 is not energized, 11 is controlled.

FIG. 3 is a flowchart showing the control operation of the control unit when the vibration detecting device 10 detects a vibration.

Hereinafter, description will be made based on the flowchart. First, an instruction for recording or reproduction of the optical disk 2 is issued, and when the rotation driving of the optical disk 2 is started, the control unit 1
2 is a first motor having a first rotation speed higher than a second rotation speed, which will be described later.
(S101). At this time, the control of the optical pickup 20 is not performed, and the focusing servo coil 24 of the actuator for driving the objective lens 21 of the optical pickup 20 is not energized.

Next, the controller 12 reads the port of the CPU provided therein (S102).

The value read into the control unit 12 at this time is an induced electromotive force generated by the focusing servo coil 24, that is, an output signal from the vibration detection circuit 13, and the control unit 12 Control of the number of rotations of the motor 11 according to the value of (S10)
3).

That is, when the output signal is low in S103, the control unit 12 determines that no vibration has been detected from the optical disc device 1 (S103).
104), the rotation of the motor 11 at the first rotation speed is continued (S105).

On the other hand, when the output signal is at the high level in S103, the control unit 12 determines that vibration has been detected from the optical disc device 1 (S106).
The motor 11 is rotated at a second rotation speed lower than the first rotation speed (S107).

Further, the control unit 12 controls the vibration detecting circuit 1 after rotating the optical disc 2 at the second rotation speed.
By detecting the output signal from the optical disc 3, the vibration of the optical disc apparatus 1 is detected, and the rotation speed of the optical disc 2 is controlled.

That is, after S107, the control unit 12 reads the port of the CPU again (S108), and when the output signal from the vibration detection circuit 13 is at the low level in S109, the control unit 12 returns to the optical disk device. 1
It is determined that the vibration from is not detected (S11
0), the rotation of the motor 11 at the second rotation speed is continued (S111).

On the other hand, if the output signal from the vibration detection circuit 13 is at a high level in S106, the control unit 12 determines that the vibration from the optical disk device 1 has been detected (S112), and Is rotated at a third rotation speed lower than the second rotation speed (S113).

Although not described in the present embodiment, after the vibration detecting operation described in the flowchart of FIG.
And so on.

In this case, the vibration of the optical disk device 1 is detected during the period from the start of the rotation drive of the optical disk 2 to the start of the writing and reading of the optical disk 2. However, the present invention is not limited to this. 2 can be performed when the writing or reading of the lens 2 is interrupted, or when the driving of the lens holder 22 by the focusing servo coil 24 is stopped.

In this embodiment, the optical disk 2 is rotated at a high rotation speed at first, and when the vibration is detected, the vibration is reduced by gradually reducing the rotation speed. However, the present invention is not limited to this embodiment, and the rotational speed is gradually increased from a low rotational speed first, and the increase in the rotational speed is stopped when vibration is detected. It is also possible to adopt a configuration in which the optical disc 2 is rotated at a rotation speed one step lower.
Further, the reduction in the number of rotations includes stopping the rotation of the optical disc 2.

The vibration detecting apparatus 10 of the present invention is not limited to the focusing servo coil 24 used in the present embodiment, and can detect vibration using other driving means. is there.

That is, the vibration detecting device 10 of the present invention
Driven during rotation of the optical disc 2, such as a tracking servo coil 25 of the optical pickup 20, a pickup base driving motor used in the pickup base driving mechanism, or a disc tray driving motor for transporting the optical disc 2. Any vibration means can be detected by using any driving means as long as the driving means is stopped for a predetermined time or more. Of course, it is also possible to detect vibration by using two or more of these driving means.

As described above, the vibration detecting device 10 of the present invention
Is different from the conventional optical disk device 30 described above in that a vibration sensor 31 or the like is provided as another element for detecting vibration, but a focusing servo coil 24 and a tracking servo coil 25 of the optical pickup 20 are used. Since the vibration detecting function is added to the existing elements, the use of the vibration detecting device 10 makes it possible to reduce the cost of the optical disc device 1 and to simplify the circuit configuration by reducing the number of components. .

Further, since the vibration detecting device 10 does not require a space for newly installing the vibration sensor 31 inside the device as in the above-described conventional optical disk device 30, it is possible to reduce the size and size of the device. Become.

Finally, it is needless to say that the present invention is not limited to the above-described embodiment, and various changes and improvements can be made within the scope described in the claims. For example, by using the vibration detecting device of the present embodiment together with a conventionally used vibration sensor or the like, it is possible to improve the vibration detection accuracy of the optical disk device. Further, the optical disk device of the present embodiment can be applied to not only the optical disk device described in the present embodiment but also disk devices of other configurations.

[0058]

As described above, the vibration detecting device according to the present invention does not include a vibration sensor or the like as another element for detecting vibration as in the conventional optical disk device, but rather uses a fork of an optical pickup. Since the vibration detection function is added to the existing elements such as the coil for the caching servo and the coil for the tracking servo, the use of the vibration detection device reduces the number of components and the cost of the optical disk device. Becomes possible.

Further, this vibration detecting device does not require a space for installing a new vibration sensor inside the optical disk device unlike the conventional optical disk device, so that the device can be made lighter and smaller.

[Brief description of the drawings]

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

FIG. 2 is a perspective view of a main part of an optical pickup according to the optical disc device of the present invention.

FIG. 3 is a flowchart illustrating a control operation of a control unit when vibration is detected by the vibration detection device according to the optical disc device of the present invention.

FIG. 4 is a block diagram showing a configuration of a conventionally used vibration detecting device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Optical disk apparatus 2 Disk 10 Vibration detection apparatus 11 Motor 12 Control unit 13 Vibration detection circuit 14 Amplifier 15 Bandpass filter 16 Comparator circuit 17 Latch circuit 18 Turntable 20 Optical pickup 21 Objective lens 22 Lens holder 23 Damper base 24 For focusing servo Coil 25 Tracking servo coil 26 Suspension spring 30 Conventional vibration detection device 31 Vibration sensor 32 Detection circuit 33 Microcomputer

Continued on the front page F term (reference) 5D090 AA01 CC09 CC18 DD03 JJ01 JJ09 5D117 AA02 BB06 CC07 FF02 5D118 AA02 BA04 BF05 EA02

Claims (9)

[Claims] 1. A vibration detecting device used in an optical disk device comprising: an optical disk driving means for rotatingly driving an optical disk; and an optical pickup for writing and / or reading data from and to the optical disk, wherein the vibration detecting device comprises: Detecting means for detecting an induced electromotive force generated from at least one drive means inside the optical disk apparatus except for the optical disk drive means by vibration of the optical disk apparatus, based on the induced electromotive force detected by the detection means; A vibration detecting device for detecting vibration. 2. The vibration according to claim 1, wherein the detecting means detects the induced electromotive force when the optical disk is rotationally driven and the driving means for detecting the induced electromotive force is not driven. Detection device. 3. The vibration detecting device according to claim 1, wherein said detecting means detects an induced electromotive force generated from a coil of an actuator for driving an objective lens of the optical pickup. 4. The detecting means is generated from a coil of a motor serving as a driving means for displacing a pickup base on which an objective lens of the optical pickup and an actuator for driving the objective lens are mounted in a radial direction of the optical disc. The vibration detecting apparatus according to claim 1, wherein the induced electromotive force is detected. 5. The vibration detecting device according to claim 1, wherein said detecting means includes a frequency detecting circuit for detecting a frequency of an induced electromotive force from said coil. 6. The vibration detecting apparatus according to claim 5, wherein the frequency to be detected is a frequency corresponding to a rotation speed of the optical disk. 7. The vibration detecting device according to claim 5, wherein the frequency detecting circuit is a band-pass filter. 8. The optical disk apparatus according to claim 1, wherein said detecting means detects a vibration of said optical disk device during a period from a start of rotation driving of said optical disk to a start of writing or reading of said optical disk by said pickup. The vibration detecting device as described in the above. 9. An optical disk device comprising the vibration detecting device according to claim 1. Description: