JPH05334708A - Optical pickup and optical disk device - Google Patents

Abstract

PURPOSE:To prevent the degradation in a recording and reproducing characteristic by providing a means eliminating dust and a stain on an optical disk surface in an optical pickup. CONSTITUTION:While rotating a spindle motor 3 at a low speed rotation in a prescribed time except recording and reproducing, a cleaning member 30 is abutted on the optical disk surface by driving an actuator 40 and the optical pickup 25 is transferred in the radial direction of the optical disk by a transfer means. Thus, dust and a stain on the optical disk surface are eliminated without bringing the optical disk 10 to contact with an objective lens 6 and without damaging the optical disk surface. Further, even when external impact is applied to an optical disk device, since the cleaning member is abutted on the optical disk previously, collision between the objective lens and the optical disk is prevented. Further, since the cleaning member is made of soft material, the impact at a collision time is reduced and the actuator is protected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to optical disc devices such as a digital audio disc (so-called compact disc) player and an optical recording / reproducing device which is an external recording device.

[0002]

2. Description of the Related Art Conventionally, devices using these optical disks as media have no means for removing dust and dirt from the surface of the optical disks.

[0003]

However, in the conventional case, when dust or dirt adheres to the surface of the optical disc, the laser light flux from the objective lens receives a light quantity loss and wavefront aberration (wavefront aberration) on the surface of the optical disc, and the reproduction signal quality is also deteriorated. Since it deteriorates, it is necessary to regularly clean the surface of the optical disc using a separate cleaning device, which is a burden on the user side.

[0004]

The structure of the present invention for solving the above-mentioned problems is as follows: (1) An objective lens for forming a spot on an optical disc, an actuator for controlling the position of the objective lens, and an optical disc closer to the optical disc side than the objective lens. (2) The cleaning member is made of felt or non-woven fabric and is softer than the surface material of the optical disk, and (3) above (1) The optical pickup, the spindle motor for rotating the optical disk by switching to either the first rotation speed at the time of recording / reproducing or the second rotation speed slower than that, and a transfer means for transferring the optical pickup in the radial direction of the optical disk. It is composed of and.

[0005]

According to the above construction, while the spindle motor is rotating at a low speed at a predetermined time other than recording and reproduction, the actuator is driven to bring the cleaning member into contact with the surface of the optical disk, and at the same time, the optical pickup is moved to the optical disk by the transfer means. Can be transferred in the radial direction. Therefore, it is possible to remove dust and dirt on the surface of the optical disk without contacting the optical disk with the objective lens and without damaging the surface of the optical disk.

[0006]

【Example】

(Embodiment 1) FIG. 1 is a plan view showing an optical disk device including an optical pickup according to an embodiment of the present invention. 2 is a side sectional view of the optical disk device, and FIG. 3 is a front sectional view.

A spindle motor 3 is mounted on the frame 1 and rotates in the R direction in FIG. A hub 4 is fixed to the shaft tip of the spindle motor 3, and the hub 4 and the clamper 11 rotate integrally by sandwiching the optical disk 10 as shown in FIG. The spindle motor 3 rotates at a relatively high rotational speed of several 100 rpm (in the case of a digital audio disk) to several 1000 rpm (in the case of an external storage device) during normal recording / reproduction, but is controlled by a control circuit (not shown) in the order of several 10 rpm. It is configured so that it can be switched to a mode in which it rotates at the rotation speed of. This can be achieved, for example, by switching the reference clock of the PLL (Phase Lock Loop) in the control circuit. The spindle motor 3 is assumed to be a DC motor, and a general DC
As a characteristic of the motor, a large amount of output torque can be obtained at low speed rotation.

One end of the carriage 5 is inserted into the guide shaft 2 whose both ends are fixed to the frame 1, and the other end thereof is inserted into the lead screw 9. A female screw that engages with the ridge of the lead screw 9 is formed inside the hole of the carriage 5 that is inserted into the lead screw 9, and when the lead screw 9 rotates, the carriage 5 is transported in the α direction in FIG. 1. In addition,
The lead screw 9, the reduction gear train 8 and the motor 7 form a transfer means 15 for the carriage 5, and access control is performed by controlling the rotation of the motor 7.

As shown in FIG. 3, the optical pickup 25 comprises an actuator 40 for controlling the position of the objective lens 6, a semiconductor laser 51, an optical component 52, a flip-up mirror 53, etc., and is mounted on the carriage 5. The actuator 40 includes a bobbin 41 and a bobbin 4 as shown in FIG.
The coil 42 is fixed to the outer periphery of the coil No. 1, a yoke 45 forming a magnetic circuit, and a permanent magnet 46, and constitutes a so-called voice coil type actuator. Bobbin 41
Is inserted into a slide shaft 21 fixed to the carriage 5 and held so that it can slide and rotate by a predetermined amount. The coil 42 is an assembly of a plurality of coils.
The focus direction (β in Fig. 3
Position) and the track direction (rotating around the sliding shaft 21 to move the objective lens 6 in the α direction in FIG. 1). This position control is performed based on the error signal separated by the optical component 52. The laser light flux 50 emitted from the semiconductor laser 51 is condensed by the objective lens 6,
A spot is formed on the recording layer of the optical disc 10. The reflected light from the recording layer is separated by the optical component 52 and then detected to reproduce the signal (details not shown).

A cleaning member 30 is mounted on the bobbin 41 on the opposite side of the objective lens 6 with the sliding shaft 21 interposed therebetween. This cleaning member 30
Optical disk 10 made of felt or non-woven material
In addition to being softer than the surface member, it is considered that the fibers inside do not entangle with each other to generate dust. In the present embodiment, the shape is formed to have a diameter of about 7 mm and a thickness of about 2 mm, but this is because the mass of the objective lens 6 is set to be substantially the same. That is, when the actuator 40 is driven, if the mass balance is deviated between the left and right sides of the sliding shaft 21, the center of gravity is displaced from the sliding shaft 21 and harmful resonance is induced. The weight of the cleaning member 30 is set as the weight. Further, as shown in FIG. 4A, the surface of the cleaning member 30 is attached higher than the curved surface apex of the objective lens 6 by δ. In this embodiment, this step difference δ is about 0.
It is set to 5 mm.

The cleaning member 30 and the actuator 40 are covered with a cover 20 attached to the carriage 5, and holes are formed only in the objective lens 6 and the cleaning member 30. In this embodiment, as shown in FIG. 4A, the objective lens 6 is slightly lower than the surface of the cover 20 in the normal position, and the user carelessly takes the objective lens 6
It prevents you from touching.

Next, the process of cleaning the optical disk 10 in the optical disk device configured as described above will be described. Generally, optical disk devices have been said to be resistant to dust,
According to the experiments conducted by the inventors and the situation of use in the market, it is assumed that the same optical disk 10 is used for a long time (about one month) in an environment of a class 10 million level, which is a dust level at home. It has become clear that static electricity is charged on the surface of the rotating optical disk 10 and a considerable amount of dust adheres thereto. Further, in a digital audio disc (so-called compact disc) or the like, since there is no cartridge for protecting the optical disc 10, oil stains or the like on fingers may adhere to the surface of the optical disc 10. When such dust or dirt adheres to the surface of the optical disc 10, the laser light flux 50 from the objective lens 6
Suffers a loss of light quantity and disturbance of the wavefront (wavefront aberration) on the surface of the optical disc 10, and the quality of the reproduced signal also deteriorates. In this embodiment, the operation mode of the optical disk device is switched to the cleaning mode at a predetermined time to remove dust and dirt adhering to the surface of the optical disk 10. Specifically, the rotation speed of the spindle motor 3 is switched as described above and set to several tens of rpm, and then the transfer means 15 is driven to transfer the optical pickup 25 to the outermost circumference of the optical disc 10. Then, the actuator 40 is driven in the focus direction, and
The cleaning member 30 is brought into contact with the optical disc 10 as shown in FIG. At this time, the semiconductor laser 51 does not emit light, and therefore the servo control of the actuator 40 is not performed. This is the distance (γ in FIG. 4A) for moving the actuator 40 from the normal position to the position in FIG. 4B.
Is as large as about 1 mm, and it is located at a position where the laser beam 50 cannot be focused on the recording layer of the optical disc 10 even if it is condensed by the objective lens 6. Therefore, the actuator 40
The coil 42 is energized with a predetermined constant current, and the cleaning member 30 contacts the surface of the optical disk 10 to mechanically determine the position. In the case of the present embodiment, when a direct current of about 50 mA is applied to the coil 42, the cleaning member 30 presses against the optical disk 10 with a force of about 20 gf. If this level of DC current is
The coil 42 will not be abnormally heated even when continuously energized for a second (a cleaning process time). In this state, since the optical disc 10 is rotating in the R direction of FIG. 4, the cleaning member 30 slides on the circumference of the optical disc 10.
Next, when the transfer means 15 of FIG. 1 is operated to slowly transfer the optical pickup 25 in the inner peripheral direction of the optical disk 10, the cleaning member 30 slides on the optical disk 10 in a spiral shape as shown in FIG. When the optical pickup 25 reaches the innermost circumference of the optical disc 10, the optical disc 1
The entire use area of 0 is completely slid. And in the process,
Most of the dust and dirt on the surface of the optical disc 10 is absorbed by the cleaning member 30, and the cleaning process is completed. In the cleaning process, the spindle motor 3 is driven at low speed because the cleaning member 30 is slid on the optical disk 10 at high speed.
This is because there is a risk of causing minute scratches on the surface, and according to experiments by the present inventor, it is necessary to rotate at 100 rpm or less at most. It has also been confirmed that low-speed rotation improves the efficiency of removing dust and dirt. Further, during the cleaning process, the cleaning member 30 comes into contact with the optical disk 10 to generate a friction load torque. At this time, since the spindle motor 3 (DC motor) is rotating at a low speed, a sufficient drive torque can be generated. The optical disk 10 can be rotated without any problem.

In the above description, the optical pickup 25 is moved from the outer peripheral side to the inner peripheral side of the optical disc 10 in the cleaning process, but it may be moved in the opposite direction. The user may give an instruction to switch the operation mode of the optical disk device to the above-mentioned cleaning mode, or the reproduction signal level may be below a predetermined value depending on the configuration (not shown) of the control circuit attached to the optical disk device. In this case, any method such as a method of switching to the cleaning step, a method of monitoring the operating time and switching to the cleaning step after a predetermined accumulated time has elapsed, or a method of forcibly switching to the cleaning step when the optical disk device is started up are available. It goes without saying that these are all applications of the present invention and are within the scope of the technical idea.

(Embodiment 2) FIG. 6 shows another embodiment.
The second embodiment is different from the above-described first embodiment in the shape of the cleaning member and the like.

In FIG. 6, 141h is a through hole provided in the bobbin 141, and a crescent-shaped cleaning member 130 is attached so as to partially cover the hole 141h. The height difference between the cleaning member 130 and the objective lens 6 in the height direction is the same as that in the first embodiment, and the material is also the same. Therefore, when the cleaning process as described above is performed, dust and dirt on the surface of the optical disc 10 are removed. In the second embodiment, a portion of the removed dust or oil that cannot be completely absorbed by the cleaning member 130 (10 in FIG. 6B).
(Indicated by 0) falls due to gravity, passes through the hole 141h, and is discarded below. Therefore, as compared with the first embodiment,
Has the ability to remove large amounts of dust.

(Embodiment 3) FIG. 7 shows still another embodiment. The third embodiment differs from the first embodiment in the structure of the actuator, the shape of the cleaning member, and the mounting method.

In the first embodiment, the bobbin 41 slides along the impulse shaft 21, but the actuator used in recent optical pickups is of a type supported by a plurality of wires or parallel leaf springs. There are many things. The third embodiment assumes a type in which the bobbin 241 is supported by four wires 221 arranged substantially in parallel. In FIG. 7, one end of the wire 221 is the wall 20 of the carriage 205.
Since the multi-ends are fixed to both side surfaces of the central portion of the bobbin 241, and four wires 221 are stretched substantially parallel to each other at 5a, the bobbin 241 is held movably in a direction substantially orthogonal to the optical disc 10. The objective lens 6 is fixed near the fixed end of the wire 221 on the bobbin 241 side, that is, substantially at the center of the bobbin 241, and is mounted substantially on the center of gravity of the bobbin 241. An annular cleaning member 230 is concentrically attached so as to surround the objective lens 6. The height difference between the cleaning member 230 and the objective lens 6 in the height direction is the same as in the first embodiment, and the material is also the same. Therefore, when the cleaning process as described above is performed, dust and dirt on the surface of the optical disc 10 are removed. In the third embodiment, the cleaning member 230 is attached concentrically with the objective lens 6 so that the center of gravity of the bobbin 241 does not deviate from the optical axis of the objective lens 6 even if the cleaning member 230 is attached. Is.

Lastly, the cleaning members 30, 130, 230 are fixed to the surface of the bobbin 41 in each of the above-mentioned embodiments. However, when the cleaning process is repeated, dirt is accumulated on these cleaning members themselves. If the mounting structure is such that the cleaning member can be replaced, the convenience is improved. It is also possible to appropriately impregnate these cleaning members with a volatile solution such as alcohol. Furthermore, since each cleaning member is closer to the optical disc side than the curved vertex of the objective lens 6 (step δ in FIG. 4A), when an external impact is applied to the optical disc device, each cleaning member first comes to the optical disc. It is possible to prevent the objective lens 6 from colliding with the optical disc 10 when the optical disc 10 hits 10. Therefore, the optical disc 10 and the objective lens 6 are not damaged by an external impact, and since each cleaning member is a soft member, the impact at the time of collision is also mitigated. Therefore, the impact resistance of the actuator 40 is also improved, which is useful for ensuring the reliability of the optical disk device and protecting the optical disk 10.

[0019]

As described above, according to the present invention, the actuator is driven to bring the cleaning member into contact with the surface of the optical disk while rotating the spindle motor at a low speed at a predetermined time other than recording and reproduction, and at the same time. By moving the optical pickup in the radial direction of the optical disk by the transfer means, dust and dirt on the optical disk surface can be removed without contacting the optical disk with the objective lens and without damaging the optical disk surface. Further, the attachment of the cleaning member does not disturb the mass balance of the movable portion in the actuator, and does not affect the control characteristics. Further, even when an external impact is applied to the optical disc device, the cleaning member comes into contact with the optical disc first to prevent the collision between the objective lens and the optical disc. In addition, since the cleaning member is a soft member, the effect of mitigating the impact in the event of a collision is produced. Therefore, it is possible to prevent deterioration of the recording / reproducing characteristics due to adhesion of dust or dirt to the optical disc, and at the same time, to secure reliability of the optical disc device and to protect the optical disc, which is of great technical significance.

[Brief description of drawings]

FIG. 1 is a plan view showing an optical disc device including an optical pickup according to a first embodiment of the present invention.

FIG. 2 is a side sectional view of an optical disc device including an optical pickup according to the first embodiment of the present invention.

FIG. 3 is a front sectional view of an optical disc device including an optical pickup according to a first embodiment of the present invention.

FIG. 4 is a cross-sectional view of an optical pickup unit according to the first embodiment of the present invention.

FIG. 5 is an explanatory diagram showing a cleaning process according to the first embodiment of the present invention.

6A and 6B are a plan view and a cross-sectional view of an optical pickup unit according to a second embodiment of the present invention.

7A and 7B are a plan view and a cross-sectional view of an optical pickup unit according to a third embodiment of the present invention.

[Explanation of Codes] 3 Spindle Motor 5 Carriage 6 Objective Lens 10 Optical Disc 15 Transfer Means 25 Optical Pickup 40 Actuator 30, 130, 230 Cleaning Member

Claims (3)

[Claims] 1. An objective lens for forming a spot on an optical disc, an actuator for controlling the position of the objective lens, and a cleaning member mounted on the actuator at a position closer to the optical disc than the objective lens. An optical pickup that features things. 2. The optical pickup according to claim 1, wherein the cleaning member is made of felt or non-woven fabric and is made of a material softer than the surface material of the optical disk. 3. The optical pickup according to claim 1, a spindle motor for rotating the optical disk by switching to either a first rotation speed during recording / reproduction or a second rotation speed slower than the rotation speed. An optical disk apparatus comprising: a transfer unit that transfers an optical pickup in a substantially radial direction of the optical disk.