JP3191867B2 - Optical head transport mechanism - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an optical head transport mechanism for transporting an optical head mounted on an optical disk device.

[0002]

2. Description of the Related Art In an optical disk apparatus, a tracking actuator (transport mechanism) for moving an optical head in a radial direction of an optical disk for tracking is used. In order to stably control the position of the optical head in the track direction, it is desirable that the mechanical load fluctuation in the transport mechanism be as small as possible. In particular, as the storage capacity of the optical disk increases, the track pitch of the disk decreases, and the mechanical load fluctuation in the transport mechanism must be reduced.

FIG. 4 is a front view showing an example of a conventional optical head transport mechanism for moving an optical head in a track direction. FIG. 5 is a right side view of the optical head transport mechanism shown in FIG. 4 as viewed from the right side. As shown in FIG. 4, the optical head 1 is held by two guides 2. Further, the optical head 1 is connected to the guide roller 4 at the connecting portion 3. The guide roller 4 is fitted on the feed screw 51. The feed screw 51 is connected to the gear 6. And
The gear 6 is connected to a rotation shaft of a motor 8 via a gear 7. The feed screw 51 is held by the base 10.

In the optical head transport mechanism configured as described above, the optical head moves in the track direction (direction B in FIG. 5) as the motor 8 rotates. Here, the feed screw 51 bends due to the pressurization of the roller that presses the optical head. In particular, the guide roller 4 has a feed screw 5
When it comes to the center of the roller 1, the deflection increases, and the friction between the guide roller 4 and the feed screw 51 increases. Then, when control is performed to rotate the motor 8 by an amount corresponding to the distance in order to move the optical head 1 by a certain distance, the optical head 1 may not move the intended distance.

[0005]

That is, in the conventional optical head transport mechanism, when the optical head 1 is transported in the track direction, a mechanical load fluctuation occurs in the transport mechanism, and the mechanical load fluctuation leads to a tracking error. There is a problem that.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and an optical head capable of stably controlling the position of an optical head by reducing a mechanical load variation occurring in a transport mechanism. An object is to provide a head transport mechanism.

[0007]

An optical head transport mechanism according to the present invention is an optical head transport mechanism having a transport member on which an optical head is suspended and configured to move the optical head by the movement of the transport member. , The transfer member is a magnetized magnetic material
In it is formed, on the side where the transport member will flex, be excited
That the provided installation electromagnets to produce a repulsive force in a direction to eliminate the deflection caused to the conveying member, the conveying unit
The material is rod-shaped, the electromagnet is vertically long, and the long axis direction is the transport part.
It is a configuration that is installed so as to be parallel to the long axis direction of the material .

[0008]

[0009]

The optical head transport mechanism may have a configuration in which the transport member is driven by a motor and includes an electromagnet current control means for controlling the electromagnet drive current in accordance with the motor drive current.

Here, the electromagnet current control means is configured to increase the electromagnet drive current when the motor drive current increases.

In the optical head transport mechanism, the transport member is, for example, a feed screw rotated by a motor.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a front view showing an example of the optical head transport mechanism according to the present invention. FIG. 2 is similar to FIG.
5 is a right side view of the optical head transport mechanism shown in FIG. The optical head 1 is held by two guides 2. Further, the optical head 1 is connected to the guide roller 4 at the connecting portion 3. The guide roller 4 is fitted on the feed screw 5. Here, the feed screw 5 is formed of, for example, a magnetic material magnetized so as to bisect the N / S pole in the length direction. The feed screw 5 is connected to the gear 6. And
The gear 6 is connected to a rotation shaft of a motor 8 via a gear 7. The feed screw 5 is held by a base 10.

Further, as shown in FIG. 2, a vertically long electromagnet 9 is provided below the feed screw 5 so that the long axis direction is parallel to the long axis direction of the feed screw 5. In addition,
The lower part of the feed screw 5 is a side on which the feed screw 5 is bent with respect to the feed screw 5. The electromagnet 9 is installed so as to generate a repulsive force on the feed screw 5 when excited.

FIG. 3 is a block diagram showing one configuration example of a control system for controlling the electromagnet 9. The motor 8 is controlled by a tracking control system 20,
1 detects a current flowing through the motor 8. Then, the drive current setting unit 22 drives the electromagnet 9 according to the detection result of the current detector 21.

Next, the operation will be described. The tracking control system 20 controls the rotation direction and the rotation amount of the motor 8 so that light from an optical system mounted on the optical head 1 irradiates a desired track. The gear 7 is provided on the rotating shaft of the motor 8.
, The gear 7 rotates. Also,
Since the gear 7 is engaged with the gear 6 attached to the feed screw 5, the feed screw 5 rotates in a direction corresponding to the rotation direction of the motor 8 by an amount corresponding to the rotation amount of the motor 8.

Since the feed screw 5 is engaged with the guide roller 4 connected to the optical head 1 via the connecting portion 3, the optical head 1 moves according to the rotation of the feed screw 5. That is, the motor 8 moves in a direction corresponding to the rotation direction of the motor 8 by a distance corresponding to the rotation amount.

The feed screw 5 bends in the direction A shown in FIG. 2 by the pressure of a roller acting to press the optical head 1. Although the bent portion differs depending on the position of the optical head 1, the friction between the guide roller 4 and the feed screw 5 increases due to the bending. As a result, the current flowing through the motor 8 increases.

The driving current of the motor 8 is detected by a current detector 21. Then, the detection result is input to the drive current setting unit 22. The drive current setting unit 22 controls the current flowing through the electromagnet 9 according to the detection result of the current detector 21. When a drive current flows through the electromagnet 9, the magnetized feed screw 5
A repulsive force (a force directed in a direction opposite to the direction A in FIG. 2) is generated between the electromagnetic force and the electromagnet 9. That is, a force is generated in a direction in which the deflection of the feed screw 5 is eliminated.

The motor drive current when the feed screw 5 has no deflection is measured in advance. Further, the relationship between the degree of deflection of the feed screw 5 and the motor drive current can be measured in advance. Further, the relationship between the amount of deflection of the feed screw 5 and the electromagnet drive current for eliminating the deflection can be measured in advance. These relationships are set in the drive current setting unit 22 in advance. Therefore, if the motor drive current can be recognized via the current detector 21, an appropriate electromagnet drive current amount for eliminating the deflection of the feed screw 5 can be determined.

Electromagnet 9 controlled by drive current setting unit 22
As a result, the deflection of the feed screw 5 is reduced, so that the frictional force generated between the feed screw 5 and the guide roller 4 is always kept within a certain range. As a result, the amount of movement of the optical head 1 in the track direction has a smaller error than the amount controlled by the tracking control system 20.

In the above embodiment, the feed screw 5
Is a magnetized magnetic material and a repulsive force is generated by the electromagnet 9. However, if the electromagnet 9 can be installed on the opposite side to the position of the electromagnet 9 shown in FIG. May be. In that case, a material that has magnetism but is not magnetized can be used as the feed screw 5.

In the above embodiment, the electromagnet driving current is set in accordance with the motor driving current. However, if another detection amount serving as an index of the deflection of the feed screw 5 can be used, the detection is performed. The electromagnet drive current amount may be set based on the amount.

Here, the optical head transport mechanism having the structure shown in FIGS. 1 and 2 has been described as an example. However, the optical head transport mechanism has a rod-shaped transport member on which the optical head is suspended, and the movement of the transport member causes the optical head to move. The present invention is not limited to the configurations shown in FIGS. 1 and 2, but may be applied to any transport mechanism having a configuration in which the optical head moves.

[0025]

As described above, according to the present invention, the optical head transport mechanism has a transport member on which the optical head is suspended, and the optical head is moved by the movement of the transport member. The conveying member is formed of a magnetized magnetic material, and generates a repulsive force on the side where the conveying member bends in a direction to eliminate the deflection generated in the conveying member when excited .
With the configuration including the electromagnets installed as described above, there is an effect that the mechanical load fluctuation occurring in the transport mechanism is reduced and the position control of the optical head can be stably performed.

[Brief description of the drawings]

FIG. 1 is a front view showing an example of an optical head transport mechanism according to the present invention.

FIG. 2 is a right side view of the optical head transport mechanism shown in FIG. 1 as viewed from the right side.

FIG. 3 is a block diagram showing one configuration example of a control system for controlling an electromagnet.

FIG. 4 is a front view showing an example of a conventional optical head transport mechanism for moving an optical head in a track direction.

FIG. 5 is a right side view of the optical head transport mechanism shown in FIG. 4 as viewed from the right side.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Optical head 2 Guide 3 Coupling part 4 Guide roller 5 Feed screw 6, 7 Gear 8 Motor 9 Electromagnet 20 Tracking control system 21 Current detector 22 Drive current setting part

Claims (4)

(57) [Claims] 1. An optical head(1)Material for suspension
(5)Conveying member(5)Light head by motion
(1)In the optical head transport mechanism for moving theThe transfer member (5) is formed of a bar-shaped magnetized magnetic material.
And On the side where the conveying member (5) is bent ,Excited
And conveying member (5)Direction to eliminate deflection occurring inAnti
PowerCauseVertically long and the long axis direction is the conveying member
(5) An electrode installed parallel to the long axis directionmagnet
An optical head transport mechanism comprising (9). (2)The transport member (5) is driven by the motor (8)
And Electromagnetic that controls the electromagnet drive current according to the motor drive current
With stone current control means (22) The optical head according to claim 1.
Transport mechanism. 3. An electromagnet current control means (22) comprising:
Claims: When the drive current increases, the electromagnet drive current increases.
3. The optical head transport mechanism according to 2. The transport member (5) is driven by a motor (8).
2. A feed screw which is rotated according to claim 2.
Item 4. The optical head transport mechanism according to Item 3 .