JPS59188850A - Optical pickup device - Google Patents

Abstract

PURPOSE:To reduce the size of an optical pickup in the radius direction of a disk by using the magnets in common to each other which are set opposite to both focus and tracking driving coils. CONSTITUTION:A focus driving coil 15 is wound round a lens barrel 14 containing an objective lens 13, and then tracking driving coils 16a and 16b are formed on the coil 15. Driving magnet units 21a and 21b formed by attaching magnets 20a and 20b to yoke plates 19a and 19b respectively are set opposite to coils 15, 16a and 16b. In this case, the N poles of the magnets 20a and 20b are set opposite to each other. These parts are stored in a housing 17 and connected and held with vertical connections by means of elastic support members 18a and 18b. In such a constitution, just a single magnet unit suffices.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an optical recording and reproducing apparatus that records or reproduces information on a disk-shaped information recording medium (hereinafter referred to as a disk) using a laser or the like as a light source. The present invention relates to an optical pickup device that performs focusing control to correct focus deviation caused by shake, etc., and tracking control to correct tracking deviation caused by disk eccentricity, etc.

Conventional Structures and Problems In recent years, as optical recording and reproducing devices such as video disks, DADs, and optical disk files have come into practical use, there has been an increasing need for smaller optical pickups and higher performance.

First, an example of a conventional optical pickup device will be explained. FIG. 1 is a sectional view of a conventional optical pick amplifier device. In FIG. 1, 1 is a semiconductor laser, 3 is a reflecting mirror, 4 is an objective lens, 5 is a disk, 6 is a lens barrel, ya and yb are tracking drive coils, sa and sb are tracking drive magnetic circuits, and 9 is a focusing device. Drive coils, 10a, 10b, 10c are focusing drive magnetic circuits, 11.12 are elastic support parts, 2
indicates the optical axis. Xx is the radial direction of the disk 5, Y
Y indicates the thickness direction of the disk 5.

The operation of the conventional optical pink-up configured as described above will be explained below.

When a tracking correction current is applied to the tracking drive coils 7a and 7b from a tracking error detection circuit (not shown), an electromagnetic force based on Fleming's left hand rule is generated between the tracking drive magnetic circuits sa and sb, and the objective The lens 4 has an elastic support member 11 in the XX direction in the figure.
．． Tracking control is performed by moving in balance with the elastic force of 12. Similarly, focusing control is performed by electromagnetic force generated between the focusing drive coil 9 and the focusing drive magnetic circuits 10a to 10C.

However, in the device configured as above, the tracking drive coils 7a, 7b and the focus drive coil 9
are arranged separately at the top and bottom of the lens barrel 6, and the tracking and 7 focusing magnetic circuits form a completely closed magnetic path, so the focus and drive shown in FIG. Spaces a, b, b created for the movement of time
, d, which increases the height of the optical pickup. Therefore, it has the disadvantage that it is difficult to make the entire optical recording/reproducing device thin, and since the dimensions of the magnetic circuit 8° and the xx force direction of the magnetic circuit 1o, that is, the radial direction of the disk 5, are large, the disk 6 It has the disadvantage that the inner circumferential part cannot be used effectively. Furthermore, the configuration of the focus and tracking driving magnetic circuits is complicated, and it is necessary to position a coil in each magnetic gap, making the assembly work complicated.

OBJECTS OF THE INVENTION The present invention aims to eliminate the drawbacks of the above-mentioned conventional methods, such as not being able to effectively use the inner circumference of the disk, and the fact that the magnetic circuit becomes complicated. The object of the present invention is to reduce the directional dimension, effectively utilize the inner circumferential portion of the disk, and simplify the configuration of a magnetic circuit for focusing and tracking drive, thereby improving assembly efficiency.

Structure of the Invention The present invention provides a lens barrel housing an objective lens for converging light emitted from a light source onto a disc-shaped information recording medium, and a coil axis is disposed on the outer periphery of the lens barrel. A first coil is wound so that the coil axis coincides with the optical axis, and a second coil is wound so that the coil axis coincides with the radial direction of the recording trunk formed on the disk-shaped information medium. , having a magnetic pole in the radial direction of the recording trunk;
In the optical pickup device, magnets are arranged such that magnetic poles face the winding surfaces of the first coil and the second coil.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. As shown in FIGS. 2 and 3, a focus drive coil 16 is wound around a lens barrel 14 housing an objective lens 13. Therefore, the coil axis of this coil 15 coincides with the optical axis of the objective lens 130. Next, tracking drive coils 16a and 16b are formed overlapping this coil 15.

The coil axes of the coils 16a and 16b are connected to the objective lens 13.
This corresponds to the radial direction of the recording track of the disk, which is hit by the light that has passed through it. Magnets 20a on yoke plates 19a and 19b,
Driving magnet units 21a and 21b to which 20b is attached
are opposed to the coils 15, 16a, and j6b. At this time, the magnets 20a and 20b are constructed such that their north poles face each other. These items are stored in the housing 17,
The upper and lower parts are connected and held by elastic support members 18a and 1sb.

In FIGS. 2 and 3, XX indicates the radial direction of recording tracks formed on the disk, zZ indicates the thickness direction of the disk, and Y'Y indicates the tangential direction of the recording trunk on the disk.

Next, the operation of this device will be explained. When a focus drive current based on a focus error signal detected by a focus error detection circuit (not shown) flows to the focus drive coil 16, a current flows between the magnetic flux emitted by the magnet units 21a and 21b and the current flowing in the Xx force direction. A driving force based on Fleming's left hand rule is generated in 22 directions.

As the elastic support members 18a and 18b are displaced in the Zz force direction by this driving force, the objective lens 13 is moved and focus control is performed. In tracking control, similar to focus control, when a tracking drive current based on a tracking error signal flows through the coils 16a and 16b, an electric current flows between the magnetic flux emitted by the magnet units 21a and 21b and the current flowing in the ZZ direction. , a driving force based on Fleming's left-hand rule is generated in the XX direction. As the elastic support members 18a and 18b are displaced in the XX direction by this driving force, the objective lens 13 is moved in the XX direction and tracking control is performed.

In addition, in the above-mentioned example, the coils 16a and 16b.

Although the magnets 21a and 21b are provided, the number of coils may be one, and the number of unnecessary magnet units may also be one. In addition, although the coil 15 and the coils 16a and 16b are provided in an overlapping manner, the lens barrel 14 is lengthened and the coil 16 is
16a and 1eb may be arranged vertically. In this case, the magnets 21 a and 21 b are naturally made longer in the vertical direction.As described above, according to the present invention, the magnets provided facing the focus drive coil and the tracking drive coil can also be used. As a result, the movement of the optical pickup is no longer restricted by the extra magnet, so the dimension of the optical pickup in the disk radial direction can be reduced, and the inner circumference of the disk can be used effectively. This also simplifies the structure.

[Brief explanation of the drawing]

FIG. 1 is a sectional front view of a conventional optical pink-up device, FIG. 2 is a new front view of an optical pink-up device according to an embodiment of the present invention, and FIG. 3 is a plan view of the same device. 13--one objective lens, 14--lens barrel,
16...--Focus drive coil, 16a, 16b
・Tracking drive coil, 17...--Housing, 2
1 a. 21b...-Magnet unit, 18a, 18b--
・Elastic kidnapping. Fig. 1-26'L Fig. 2 S Fig. 3

Claims (1)

[Claims] A lens barrel housing an objective lens for converging light emitted from a light source onto a disc-shaped information recording medium is provided, and a coil axis is arranged around the outer periphery of the lens barrel so that the axis of the coil coincides with the optical axis of the objective lens. a first coil wound around the disk, and a second coil wound so that the coil axis coincides with the radial direction of the recording track formed on the disc-shaped information medium, A former pickup device having a magnetic pole in a direction, and a magnet arranged so that the magnetic pole faces the winding surfaces of the first coil and the second coil.