JPH11203684A - Optical disk device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent it that the operation of a two-dimensional actuator becomes insperative because foreign matters are stucked and adhered in the gap between a shaft guiding a lens holder freely in a focusing direction and a tracking direction by moving the lens holder while driving the two-dimensional actuator with a prescribed time interval whilst a power source is supplied to this optical disk device. SOLUTION: A lens holder 102 holding the objective lens 101 of a two- diementional actuator has coils 103,104 for drives of a focusing direction and a tracking direction and is engaged with a shaft 106 with a pipe 105 fixed to the holder. When foreign matters are stuck in the gap between the shaft 106 and the pipe 105 and the foreign matters are closely adhered to them in the gap while the shaft 106 and the pipe 105 are not operated for a longtime, the foreign matters generate adhesion and the two-dimensional actuator becomes inoperative. Then, when the device is in an electric conduction state, the obstacle of adhesion is avoided by driving the lens holder 102 while making driving currents to flow through the coils 13, 14 with a prescribed time interval.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a CD, C
The present invention relates to an optical disk device such as a D-ROM, MO, and DVD.

[0002]

2. Description of the Related Art In an optical disk device, it is necessary to position a light spot narrowed down by an objective lens on an optical disk recording film in order to read information on the optical disk recording film or write information on the optical disk recording film.
In addition, it is necessary that the light spot is positioned substantially at the center of the track on which information is written. A two-dimensional actuator is a mechanism for moving the objective lens in accordance with surface deviation and eccentricity of the optical disk in order to position the light spot on the recording film of the optical disk or at the center of the track.

A two-dimensional actuator can move the objective lens in a direction substantially perpendicular to the optical disk surface (focus direction) and in a direction substantially parallel to the radial direction of the optical disk (tracking direction) in order to position the objective lens on the optical disk recording film. The structure of the two-dimensional actuator is described in, for example, Yoshito Tsunoda, "Basics and Application of Optical Disk Storage", IEICE, pp.128-131. Among them, the object of the present invention is a two-dimensional shaft sliding type actuator.

[0004] A two-dimensional shaft-sliding type actuator will be described below with reference to FIG. FIG. 1 (a),
(B) is a cross section of a two-dimensional shaft sliding type actuator. FIG. 1A is a sectional view taken along a plane perpendicular to the radial direction of the optical disk and passing through the center of the shaft. FIG. 1B is a cross-sectional view of a plane parallel to the radial direction of the optical disk and passing through the center of the shaft. The lens holder 102 for holding the objective lens 101 has a coil 10 for driving in the focus direction.
3 and the tracking direction driving coil 104 are fixed. A pipe 105 is inserted and fixed so as to penetrate the lens holder 102 in the focus direction.

A pipe 105 is fitted to an optical head body (not shown) or a body of a movable portion which is a part of the optical head, directly or through some members to a shaft 106 fixed substantially perpendicular to the optical disk surface. ing. Similarly, a coil 103 for driving in the focus direction and a coil 104 for driving in the tracking direction are sandwiched directly or through some members between the optical head main body (not shown) or the body of the movable part which is a part of the optical head. The magnet 107 is fixed in such a manner as to be inserted.

A magnetic circuit is formed by the magnet 107 and two types of coils. The shaft 106 is coated with a resin having a low coefficient of friction, and the gap between the shaft 106 and the pipe 105 is several μm to 20 μm.
There is a gap of about μm. Therefore, the lens holder 102
The pipe 105 can move freely in the focus direction and the tracking direction while being guided by the shaft 106.

The optical head has a detection system for detecting the amount of deviation of the position of the light spot using the reflected light from the optical disk recording film. The two-dimensional actuator drives the lens holder 102 by the magnetic circuit in accordance with the signal from the detection system, and operates so that the light spot follows the surface deviation or eccentricity of the optical disk due to the rotation of the optical disk.

The two-dimensional actuator is incorporated in an optical disk drive mechanism as shown in FIG. FIG.
FIG. 3 is an explanatory diagram illustrating an example of a mechanical unit of the optical disc device.
A spindle motor 202 is fixed to a base 201. An optical disk 203 is detachably attached to a spindle motor 202 and rotates at a predetermined rotation speed. In this example, the optical head is separated into an optical head fixing section 204 and an optical head movable section 205. The optical head fixing unit 204 is fixed to the base 201 and has a light source and a function of detecting a servo signal and an information signal. The optical head movable section 205 is mounted on the base 201 so as to be movable in the radial direction of the optical disk 203, and is driven by a voice coil motor (not shown). The light emitted from the optical head fixing unit 204 is reflected toward the optical disk 203 by the rising mirror 207 and forms a light spot on the optical disk recording film of the optical disk 203 by the objective lens 209 in the two-dimensional actuator 208.

The movable range of the optical head movable section 205 is limited by a stopper 206 mounted on the base 201. Normally, the stopper 206 is designed so as to reduce the impact to such an extent that the optical head does not break even if the optical head movable section runs away due to an abnormality such that the control in the tracking direction is lost and the optical head is runaway. .

At the time of starting the optical disk apparatus, since the light spot is not on the optical disk recording film and the signal for focus control is not in an effective range, the two-dimensional actuator is largely moved in the focus direction to search for the position of the optical disk recording film. Servo pull-in is performed when the target point of the focus servo signal is reached near the optical disc recording film position,
The focus servo is set to a state where information can be recorded and reproduced.

[0011]

In the above-described optical disk apparatus, there is a case where a foreign substance adheres to a gap between the shaft 106 and the pipe 105 and the two-dimensional actuator cannot be operated.

The problem to be solved by the present invention is that if the foreign matter is, for example, a small amount of an organic substance, the shaft 106 and the pipe 105 will stick if the shaft 106 and the pipe 105 do not operate for a long time (hereinafter simply referred to as sticky). ) To solve the phenomenon in which the two-dimensional actuator does not operate.

Such a phenomenon occurs in an optical disk device having a structure in which a preload is applied to a lens holder 102 of a two-dimensional actuator in a direction perpendicular to the axis of a shaft 106, or an optical disk device in which the shaft 106 is horizontal. This is likely to occur when surface pressure is applied to the pipe 105 and the shaft 106 by the weight of the member installed and incorporated in the lens holder 102.

As a cause of the adhesion of the foreign matter which causes such a phenomenon, for example, an operator accidentally touches the shaft 106 during an assembling operation, or tweezers or the like holding the shaft 106 at the time of assembling become dirty. It is difficult to completely eliminate work management, thoroughness, and improvement of the work environment.

Such a small amount of foreign matter does not hinder normal operation other than malfunction due to a phenomenon such as adhesion. Also, once the adhesive has been peeled off, it will not be reproduced unless it does not operate again for a long time and adheres.

[0016]

In order to solve such a problem, if power is supplied to an optical disk device, a two-dimensional actuator is driven at predetermined time intervals to prevent the occurrence of sticking. Things. In addition, if sticking occurs due to being left without being energized, it is detected that the operation of the two-dimensional actuator is abnormal from the focus servo signal or the like, or that the focus servo is not normally applied, The optical head is driven in the radial direction of the optical disk and collides with the stopper 206 at a predetermined acceleration to remove the adhesive and to operate normally. These means may be used in combination.

[0017]

Embodiments of the present invention will be described with reference to FIG. FIG. 3 is an explanatory diagram showing the configuration of the optical disk device. In the present invention, the configuration of the two-dimensional actuator and the configuration of the mechanism of the optical disk device are the same as those described in the related art.

Normally, the optical disk device 301 is operated by a controller 302 for controlling the operation inside the optical disk device. This controller 302
Has a function of converting a command from a higher-level device 303 such as a personal computer into an actual operation of the device and operating the device, and a function of performing a necessary operation by the device itself. The controller 302
An optical head, a mechanism 30 such as an optical disk loading mechanism, etc., via an operation / detection circuit 304 of the optical disk apparatus.
5 is operated. Further, the controller 302 includes various sensors (not shown) installed in the mechanism unit 305.
Or, it receives a signal from the operation circuit and gives support for the next operation, and when an abnormality occurs, instructs to redo the operation.

The first embodiment will be described below. The controller 302 functions as long as the optical disk device is energized, and usually has a timer function. Therefore, if the current is in the energized state, a two-dimensional actuator driving current is caused to flow through the operation / detection circuit 304 at predetermined time intervals to drive the two-dimensional actuator. The driving direction may be either the focus direction or the tracking direction, or both. The amount of driving is preferably an amount by which the entire stroke of the two-dimensional actuator is moved, but may be smaller. The time interval is preferably about 30 min to 2 h.

FIG. 4 shows an example of the relationship between time and drive current. In the example of this figure, the controller 302
The time is monitored by a timer which is a function of the device, and a drive current is supplied to the two-dimensional actuator when 30 minutes have elapsed. In this example, the drive current for one reciprocation is to flow, but it may flow for several reciprocations. After a further 30 minutes, this operation is repeated. This operation is repeated until the power supply to the optical disk device 301 ends or a medium is inserted and a normal operation is performed.

When the medium is ejected while the power is turned on, or in a so-called standby mode (a mode in which the semiconductor laser is not lit to protect the semiconductor laser as a light source of the optical disk apparatus, in which both the semiconductor laser and the spindle are stopped). Mode, etc.), this operation is repeated even when the focus servo is not applied. In this case, the time monitoring may be performed by measuring the time point at which the focus servo is disengaged as t = 0, or may be performed every 30 minutes from the time when the power is turned on at t = 0. By operating the two-dimensional actuator at predetermined time intervals in this manner, no malfunction due to adhesion occurs.

Next, a second embodiment will be described with reference to FIGS. The function of claim 1 is a very effective means for preventing the malfunction of the two-dimensional actuator from occurring, but cannot function when power is not supplied to the optical disk device. If the power supply is left for a long time without being turned on, the two-dimensional actuator may malfunction.

When a malfunction of the two-dimensional actuator to be solved by the present invention occurs, the two-dimensional actuator applies focus servo, so that the two-dimensional actuator cannot operate when trying to operate in the focus direction. . In this case, the optical head fixing unit 20
The focus servo signal detected by the photodetector provided in No. 4 does not have a predetermined waveform.

The operation / detection circuit 304 detects that the focus servo signal does not have a predetermined waveform, and reports it to the controller 302. The controller 302 operates
The detection circuit 304 is instructed to supply a drive current for driving the optical head movable section 205.

The optical disk device is provided with the stopper 206 for limiting the operation range of the optical head movable section 205 as described in the related art. The stopper 206 is provided at a position where the light spot can move within an effective recording / reproducing range from the inner circumference to the outer circumference of the optical disk. The stopper 206 is made of rubber, a leaf spring, or the like, and is usually designed to reduce the impact to a collision acceleration at which the optical head movable unit 205 is not broken even if the optical head movable unit runs away for some reason. .

The current for driving the optical head movable section 205 is:
The optical head movable part 205 is once moved to the outer peripheral part of the optical disk, and then moved so as to collide with the stopper 206 on the inner peripheral side. The magnitude of the impact at the time of the collision is set to be in the range of several G to several tens G.

In this way, when the optical head movable section 205 receives an impact, the two-dimensional actuator mounted on the optical head movable section 205 is released from the adhesion by the foreign matter and can be operated. Thereafter, the operation of applying the focus servo again is performed. In this case, since the malfunction of the two-dimensional actuator has been corrected, the focus servo can be normally applied.

[0028]

As described above, it is possible to avoid the problem of sticking due to the long-time pressing of the foreign matter that has entered the sliding portion of the two-dimensional actuator.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a two-dimensional actuator according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing an example of a mechanical unit of the optical disk device.

FIG. 3 is an explanatory diagram illustrating an example of a configuration of an optical disk device.

FIG. 4 is a characteristic diagram showing an example of a relationship between time and a drive waveform.

[Explanation of symbols]

101: Objective lens, 102: Lens holder, 103 ...
Focus direction driving coil, 104: Tracking direction driving coil, 105: Pipe, 106: Shaft, 107: Magnet, 201: Base, 202: Spindle motor, 203: Optical disk, 204: Optical head fixing unit, 205: Optical head movable portion, 206: stopper, 207: rising mirror, 208: two-dimensional actuator, 209: objective lens, 301: optical disk device, 302: controller, 303: host device, 304
... operation / detection circuit, 305 ... mechanical unit.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Shigeki Yamazaki 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture

Claims (4)

[Claims] A lens holder for holding the objective lens; a lens holder for holding the objective lens; forming a light spot by condensing light emitted from the light source on a recording film of the optical disk; and substantially parallel to an optical axis of the objective lens. Pipe that passes through the lens holder,
It consists of a shaft through which the inside diameter of the pipe is guided, and the axial direction of the shaft while the objective lens is held in the lens holder,
And an optical head having a structure rotatable in the direction of rotation with respect to the axis of the shaft, wherein power is supplied to the optical disk device in an optical disk device having a structure in which a part or the whole of the optical head is movable in the optical disk radial direction. An optical disk device wherein the lens holder is moved at predetermined time intervals during the operation. 2. A light source, a lens holder for holding the objective lens having an objective lens for condensing light emitted from the light source on a recording film of an optical disc to form a light spot, and substantially parallel to an optical axis of the objective lens. Pipe that passes through the lens holder,
It consists of a shaft through which the inside diameter of the pipe is guided, and the axial direction of the shaft while the objective lens is held in the lens holder,
An optical head having a structure rotatable in the direction of rotation with respect to the axis of the shaft. In an optical disc apparatus having a structure in which a part or the whole of the optical head is movable in the radial direction of the optical disc, the objective lens is connected to the axis of the shaft. In the direction of the optical disk, the optical spot is positioned on the recording film of the optical disk, and when servo operation is performed, if this fails, the head movable in the radial direction of the optical disk collides with a stopper that limits the movable range, and the optical spot is again emitted. An optical disc device which performs an operation of positioning the optical disc on a recording film of an optical disc. 3. A lens holder for holding a light source, an objective lens for condensing light emitted from the light source on an optical disc recording film to form a light spot, and substantially parallel to an optical axis of the objective lens. Pipe that passes through the lens holder,
It consists of a shaft through which the inside diameter of the pipe is guided, and the axial direction of the shaft while the objective lens is held in the lens holder,
An optical head having a structure rotatable in the direction of rotation with respect to the axis of the shaft. In an optical disc apparatus having a structure in which a part or the whole of the optical head is movable in the radial direction of the optical disc, the objective lens is connected to the axis of the shaft. When the operation is failed by moving the light spot on the optical disk recording film by moving the optical spot in the direction, and rotating the lens holder about the axis of the shaft if this fails, the operation of positioning the light spot on the optical disk recording film again An optical disk device characterized by performing: 4. An optical disk device comprising an optical head combining any two or more of claim 1 to 3.