JPH03216820A - Optical pickup - Google Patents

Abstract

PURPOSE:To lessen the influence on focusing servo and tracking servo by executing the supply of an electric current to coils via an FPC and extending the shape of the FPC from both sides of a fixing part in the direction approximate to the tracking direction. CONSTITUTION:A focusing control circuit supplies the current to the focusing coils 17a, 18a via the FPC 31. The supply of the large-capacity current is, therefore, possible and the high-speed access is possible. The 1st and 2nd base parts 31b, 31c of the FPC 31 deflect at the time of tracking, thereby obviating the exertion of the adverse influence of the rigidity of the FPC 31 on the movement of a lens holder 16. Further, the front end part 31d of the FPC 31 deflects at the time of focusing. The influence on the focusing servo and tracking servo is lessened in this way.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention provides a fixed part provided with a magnetic circuit, an elastic body flexible in the focusing direction with respect to the fixed part, and an elastic body flexible in the tracking direction with respect to the fixed part. a movable part provided via an elastic pair and on which an objective lens is disposed, and a movable part provided in the movable part,
The present invention relates to an optical pickup having a coil disposed in a magnetic gap of the magnetic circuit, and in which the movable part is driven in a tracking direction and a focusing direction by passing a current through the coil.

(Background of the Invention) Conventionally, in a tip pickup, when a coil is provided in a movable part, a flexible Litz wire with a small wire diameter is often used to supply current to the coil.

(Problem to be Solved by the Invention) However, in recent years, there has been a growing demand for high-altitude access for optical backups. In order to achieve this high-altitude access, it is conceivable to strengthen the magnetic field of the magnetic circuit and increase the current flowing through the coil2. but,
Conventional litz wires with a thin wire diameter have been unable to pass large amounts of current.

Therefore, it is possible to use FPC, but there is a problem that FPC has high rigidity and affects the focusing servo and tracking servo of the movable part.

The present invention has been made in view of the above problems, and its purpose is to provide an FP that can supply a large amount of current to the coil.
The purpose of the present invention is to provide a Qi pickup that uses C and has less influence on the four-force shisig servo and tracking servo.

(Means for Solving the Problems) The present invention for solving the above problems includes a fixed part provided with a magnetic circuit, an elastic body flexible in the focusing direction with respect to the fixed part, and an elastic body flexible in the tracking direction with respect to the fixed part. a movable part provided via an elastic pair and provided with an objective lens; and a coil provided in the movable part and disposed in a magnetic gap of the magnetic circuit, and a current is caused to flow through the coil. Accordingly, in an optical pickup in which the movable part is driven in the tracking direction and the focusing direction, current is supplied to the coil through the FPC, and the shape of the FPC is changed from both sides of the fixed part to each other in the tracking direction. It has a bilaterally symmetrical approximately T-shape consisting of first and second bases extending in the approaching direction and merging, and a tip extending from the confluence of the first and second bases and reaching the movable part. It is something.

(Function) In the optical pickup of the present invention, the movable part provided with the objective lens and the coil is provided on the fixed part with an elastic body flexible in the focusing direction and an elastic body flexible in the tracking direction. There is. Since the coil is disposed in the magnetic gap of the magnetic circuit provided in the fixed part, by passing current through the coil, the movable part is driven in the focusing direction and the tracking direction.

The current is supplied to the coil from the first and second bases that extend toward each other in the tracking direction from both sides of the fixed part and join together, and from the junction of the first and second bases. This is carried out via a left-right symmetrical substantially T-shaped FPC consisting of a tip end that reaches the movable part.

(Example) Next, one embodiment of the present invention will be described using the drawings.

FIG. 1 is a plan configuration diagram of an optical pickup according to the present invention, and FIG. 2 is a cross-sectional configuration diagram of FIG. 1.

In these figures, 1 has guide bars 2.3 on both sides.
This is the base (fixed part) of the optical pickup that is slidably engaged with the optical pickup. A linear motor (not shown) is provided on the base 1, and a guide bar 2. 3 will guide you to move. A hole 1a is formed approximately in the center of the base 1. 4 is a sub-base in which a hole 4a opposite to the hole 1a is bored. On this sub-base 4, approximately Y-shaped yokes 5 and 6 are attached. Magnets 7 and 8 are attached to the yoke 5, and magnets 9 and 10 are attached to the yoke 6, respectively, forming magnetic circuits I and II, respectively.

Reference numerals 11 and 12 designate leaf springs whose base ends are attached to the yokes 5 and 6, whose distal ends are connected to the relay member 13, and are flexible in the tracking direction (direction of arrow T in FIG. 1).

Reference numeral 14.15 is a leaf spring whose base end is attached to the relay member 13, whose distal end is connected to the lens holder 16 (movable part), and which is flexible in the focusing direction (direction of arrow F in FIG. 2). . An objective lens 23 is attached to the lens holder 16.

Attached to the side surface of the lens holder 16 are coils 17 and 18 arranged in the magnetic gap between the magnetic circuits I and II. Furthermore, the coil 17 is the focusing coil 1
7a and tracking coils 17b and 117c. Similarly, the coil 18 is the focusing coil 1
8a and tracking coils 18b and 18c.

25 is a mirror holder attached to the lower surface of the base 1. A flange portion 25a is provided on the side surface of this mirror holder 25.
A hole 25b is formed in the flange portion 25a.
are drilled in three locations.

On the other hand, a perforated hole 1c is formed in the lower surface of the base 1, and is opposed to a hole 25b formed in the flange portion 25a.

The mirror holder 25 is attached to the lower surface of the base 1 using a screw 24 that loosely fits into the hole 25b of the flange portion 25a and screws into the screw hole 1c of the base 1.

Inside the mirror holder 25, a pair of pentamirras 19 and 20 are disposed that provide a 90° deflection angle between the input optical axis and the output optical axis. A laser beam from a semiconductor laser (not shown) travels toward the objective lens 23 via a pair of pentamirrors 1, 9, and 20. Further, 21 is a recording medium.

31 is an FPC that supplies drive current to the forcing coil 18a and the tracking coil 18b, respectively. This FPC 31 includes a base attachment part 31a that is attached to the sub-base 4, and a base attachment part 31a that is attached to the sub-base 4.
first and second base portions 31b and 31c that rise from both sides of a and then extend toward each other in the tracking direction and join together, and these first and second base portions 31
focusing coils 17a, 18a, tracking coils 17b, 17c, 18b . 18c and a distal end portion 31d connected to the tip portion 31d, which has a symmetrical T-shape.

Next, the operation of the above configuration will be explained. The base 1 moves in the track direction of the recording medium 21 while being guided by guide bars 2 and 3 by a linear motor (not shown). After moving to the target track, data is written/written to the recording medium 21.

At this time, focusing is performed by a focusing control circuit (not shown) via the focusing coil 17 via the FPC 31.
A and 18a are supplied with current. Then, coil 17.1
A thrust force in the focusing direction is generated at 8, and the lens holder 16 moves in the focusing direction against the elastic force of the leaf springs 14 and 15. Then, when the supply of this current is canceled, the lens holder 16 returns to its original position.

Next, tracking is performed by a tracking control circuit (not shown) or tracking coils 17b, 17c, 18b, 18c.
A current is supplied to the FPC 31 through the FPC 31. Then, a thrust force in the tracking direction is generated in the coils 17 and 18, and the lens holder 16 moves in the tracking direction against the elastic force of the leaf springs 11 and 12. Then, when the supply of this current is canceled, the lens holder 16 returns to its original position.

The laser beam emitted from the semiconductor laser is bent in its traveling direction by 90 degrees by pentamirrors 19 and 20, and is projected onto the recording medium 21 via the objective lens 23.

According to the above configuration of the optical pickup that uses an FPC that can supply a large amount of current to the coil and has little effect on the forcing servo and tracking servo,
Focusing coil 18a and tracking coil 1
Since the current is supplied to 8b via the FPC 31, a large amount of current can be supplied. Therefore,
High-speed access is possible.

Also, during tracking, the first and second bases 31b and 31c of the FPC 31 are bent, so that the lens holder 1
The rigidity of the FPC 31 does not adversely affect the movement of the FPC 31.

Furthermore, during focusing, the tip 31 of the FPc 31
By bending d, the FPC can move the lens holder 16.
The stiffness of 31 has no adverse effect.

(Effects of the Invention) As described above, according to the present invention, current is supplied to the coil through the FPC, and the shape of the FPC is extended so that both sides of the fixed part approach each other in the tracking direction. By creating a bilaterally symmetrical approximately T-shape consisting of first and second base portions that extend and merge, and a tip portion that extends from the merged portion of the first and second base portions and reaches the coil of the movable portion, Using an FPC that can supply a large amount of current to the coil, it is possible to realize an optical pickup that has less influence on forcing servo and tracking servo.

[Brief explanation of drawings]

FIG. 1 is a plan configuration diagram of an optical pickup according to the present invention, and FIG. 2 is a cross-sectional configuration diagram of FIG. 1. In these figures, 1, II... Magnetic circuit 1... Fixed part (base) 11, 12, 14. 15... Elastic body (plate spring) 16
...Movable part (lens holder) 17.18...Coil 31...FPC 3lb...First base 31C...Second base 31d...Tip part

Claims (1)

[Claims] A fixed part (1) provided with a magnetic circuit (I, II), an elastic body (14, 15) flexible in the focusing direction with respect to the fixed part (1), and a flexible body (14, 15) in the tracking direction. A movable part (16) provided via a flexible elastic pair (11, 12) and on which an objective lens (23) is disposed;
6) and coils (17, 18) disposed in the magnetic gap of the magnetic circuit (I, II), and by passing a current through the coil (17, 18), the movable part ( In the optical pickup in which the coil (16) is driven in the tracking direction and the focusing direction, the coil (17) is driven in the tracking direction and the focusing direction.
. first and second bases (31b, 31c);
The coils (17, 18) of the movable part (16) extend from the confluence of the first and second bases (31b, 31c).
) An optical pickup characterized in that it has a left-right symmetrical approximately T-shape consisting of a tip portion (31d) extending to a point (31d).