JPH0950635A - Optical pickup drive - Google Patents

Abstract

(57) [Abstract] [Purpose] A compact and low-cost optical pickup driven in the focusing and tracking directions,
It can be driven at high speed. [Structure] A holder 2 for holding an objective lens 1 is supported by double-wound coils 9 and 10 formed by folding an electric wire in two. When a current is applied to the double-wound coils 9 and 10, a current flows between the adjacent electric wires in the opposite direction, a repulsive force is generated, and the coils are expanded. The double winding coil 9 is used for focusing servo, and the pair of double winding coils 10 arranged to face each other is used for tracking servo.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disc apparatus for projecting a light spot on a disc and reading information optically, so that an optical pickup is arranged in a tracking direction and a focus direction so as to focus the light spot on a pit of the disc. The present invention relates to an optical pickup driving device that drives the optical pickup.

[0002]

2. Description of the Related Art In recent years, as optical disc devices have become smaller, have higher performance, and are less expensive, the demands on optical pickup drive devices have also increased. A conventional optical pickup driving device will be described below.

FIG. 5 is an exploded perspective view of a conventional optical pickup driving device. The objective lens 1 is held by a holder 2, and the holder 2 is movably supported by four holding wires 3. . A focus coil 4 and a tracking coil 5 are wound around the holder 2 in directions perpendicular to each other. The yoke 6 and the permanent magnet 7 are the casing 8
It is mounted on and forms a magnetic circuit. In this magnetic circuit, the holder 2 having the focus coil 4 and the tracking coil 5 wound therein is incorporated.

In the above structure, by driving the objective lens 1 in the focus direction and the tracking direction,
The light spot is focused on the pit of the disc at high speed and with high accuracy. That is, when driving in the focus direction, by applying a current to the focus coil 4,
As a voice coil motor, a driving force is applied in the focus direction indicated by arrow A. Further, when driving in the tracking direction, a current is applied to the tracking coil 5 to obtain a driving force in the tracking direction indicated by arrow B as a voice coil motor.

[0005]

However, in the above-mentioned conventional configuration, the voice coil motor is used as the actuator, and the magnetic circuit including the focusing coil, the tracking coil, the yoke and the permanent magnet 7 is required, and the moving part The number of parts is large, the weight is heavy, and there are problems in terms of downsizing, cost reduction, and speedup.

Therefore, the present invention provides a small-sized and high-speed optical pickup driving device by constructing a completely new actuator that does not use a voice coil motor or a holding wire.

[0007]

In order to solve the above-mentioned problems, an optical pickup driving device of the present invention holds an objective lens by a coil that allows currents to flow in opposite directions between adjacent electric wires. The holder is supported so as to be movable in the focusing direction and the tracking direction of the objective lens with respect to the disc.

[0008]

According to the above structure, when a current is applied to the coil, a current flows in the opposite direction between the adjacent electric wires. Under the influence of the magnetic field generated by this current, the adjacent wires are repulsed so that they are separated from each other, and the coil is expanded. Therefore, drive control of the optical pickup can be performed by selectively applying a current to the coil according to the focusing direction or the tracking direction.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An optical pickup driving device of the present invention will be described below with reference to the drawings. In the optical pickup driving device shown in FIG. 1, a holder 2 for holding an objective lens 1 includes two double-winding coils 9 for tracking servo and a double-winding coil 10 for focusing servo that face each other with the holder 2 interposed therebetween. By holder 2
Is movably supported.

The other end of each of the double-wound coils 9 and 10 whose one end is fixed to the holder 2 is fixed to the casing 8, and its concrete structure is shown in FIG. That is, each double coil has one
This electric wire is folded in two, and the bent end 11 is fixed to the holder 2 and the other end 12 side is fixed to the casing 8.

The operation principle of moving the holder by each of these double coils will be described with reference to FIGS.
FIG. 4 shows a sectional view of the coil of FIG.
When current is applied from the 2 side, current flows in the opposite direction between adjacent electric wires. Due to the influence of the magnetic field indicated by the arrow 14 between the adjacent electric wires 13 of the double winding coil due to this current,
Repulsive force (repulsive force) 15 works. Due to this repulsive force, the double-wound coil operates in the extending direction.

In this embodiment, the above action is utilized as an actuator for driving the objective lens 1 and the holder 2. That is, for tracking servo, a current is selectively applied to one of the two double-wound coils 9 in accordance with the direction in which the objective lens 1 and the holder 2 are moved, whereby the coil is expanded and the tracking is performed. Servo. When driving in the focus direction, 2
By applying an electric current to the double-wound coil 10, the double-wound coil 10
To extend the focus servo.

Another embodiment of the present invention shown in FIG. 2 is configured such that the objective lens 1 and the holder 2 are driven in parallel to the disk, and is characterized in that a support plate 16 is provided. . The support plate 16 has one end rotatably supported by the holder 2 and the other end engaged with a groove 17 provided in the casing 8 so that the parallelism between the holder 2 and the disk is maintained. There is.

[0014]

As described above, the optical pickup driving device of the present invention is constructed such that the objective lens is supported by the coil which allows the electric current to flow in the opposite direction between the adjacent electric wires.
Magnetic circuits such as permanent magnets and yokes, tracking coils and focusing coils are not used. Therefore, the number of parts is small, the size is small, the cost is low, and the driving can be performed at high speed.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of an optical pickup driving device of the present invention.

FIG. 2 is a perspective view showing another embodiment of the optical pickup driving device of the present invention.

FIG. 3 is a perspective view of a double-winding coil used in the device.

FIG. 4 is a sectional view for explaining the operating principle of the double-winding coil.

FIG. 5 is an exploded perspective view showing a conventional optical pickup driving device.

[Explanation of symbols]

 1 Objective Lens 2 Holder 3 Holding Wire 4 Focusing Coil 5 Tracking Coil 6 Yoke 7 Permanent Magnet 8 Casing 9,10 Double Coil

Claims (1)

[Claims] 1. A holder for holding an objective lens is movably supported in a focusing direction and a tracking direction of the objective lens with respect to a disk by a coil in which electric currents flow in mutually opposite directions between adjacent electric wires. Optical pickup drive device.