JPS62219240A - Lens driving device - Google Patents

Abstract

PURPOSE:To make a lens driving device small in size, light in weight and heighten efficiency by constituting a focus coil and a tracking coil by a printed coil formed by rolling an insulator sheet having a spiral conductor formed on the surface. CONSTITUTION:A focus coil 2 and a tracking coil 3 are constituted of a movable part constituted of the printed coil formed by rolling the insulator sheets 4, 5 having the spiral conductors 2a, 3a formed on the surface and fixed part, and supporting part that fits the movable part oscillatably to the fixed part. By using printed coil for the focus coil 2 and the tracking coil 3 they can be made small in size and light in weight. Further, as movable part including a lens 1 and the focus coil and tracking coil 2, 3 can be made light in weight, efficiency can be heightened. As winding work becomes unnecessary, productivity can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a lens driving all device in a pickup section of an optical information signal reproducing device such as a so-called CD (compact disc) player. It is designed so that it can be converted into pumice and pumice.

(Prior Art) In general, in an optical information signal reproducing device, various information signals are recorded on the surface of a disk in the form of bits by irradiating a laser beam focused by an information reading lens. It is designed to play the signal.

- In this type of playback device, in order to accurately reproduce the information signal, it is necessary to focus the laser beam on the surface of the disk, and also to accurately focus the track formed by the pit row. need to be traced.

Therefore, in this type of playback device, focusing control is performed to adjust the distance between the lens and the disk surface by driving the lens in the direction of the optical axis of the lens, that is, in the focusing direction, and in the radial direction of the lens, that is, in the tracking direction. Tracking control is performed to accurately on-track the laser beam by driving the laser beam.

In order to perform such control, the lens is placed in a magnetic circuit, and control signals are supplied to the magnetic circuit in accordance with the distance difference between the lens and the disk surface and the track deviation. By doing so, this lens is driven in the focusing direction and the tracking direction.

(Problem to be solved by R Ming) By the way, since the above magnetic circuit is composed of a coil and a magnet etc. wound around the bobbin to which the above lens is attached, the work of winding the coil around the above bobbin is difficult. The problem is that it is complicated.

Also, since the coil takes up a lot of space and is heavy, this type of device can be miniaturized! This is not preferable in terms of achieving a length of 1 m, and there is also the problem that a relatively large hole is required to drive the lens, resulting in poor efficiency.

(Means for Solving the Problems) The present invention has been made in view of the above-mentioned circumstances, and provides a lens drive that can be made smaller, lighter, and more efficient, and can also improve productivity. The purpose is to provide equipment.

In order to achieve this object, the present invention uses a lens driving device, as shown in FIG. A focus coil 2 for driving the lens 1 in the optical axis direction (in the six directions of arrows), and a tracking coil 3 for driving the lens 1 in the radial direction of the disk (in the direction of arrow B). 2 and tracking coil 3 on an insulator sheet 4 having spiral conductors 2a and 3a formed on its surface.
．． 5, a fixed part, and a support part to which the movable part is swingably attached to the fixed part.

(Function) Lens drive with the above-mentioned configuration! According to the PII device, by using printed coils for the focus coil 2 and tracking coil 3, it is possible to reduce the size and weight.

Furthermore, since the weight of the movable parts including the lens 1, focus coils, and tracking coils 2 and 3 can be reduced, efficiency can also be improved.

Furthermore, since the conventional winding work is not required, productivity can be improved.

(Embodiments) Hereinafter, preferred embodiments of the present invention will be described in detail with reference to FIGS. 1 to 8.

FIG. 1 is an exploded perspective view of a lens driving device according to this embodiment. A movable part consisting of a focus coil unit 7 formed with a movable part, a fixed part consisting of a yoke 9 and a magnet 10 forming a magnetic circuit for driving this movable part, and a focusing part for focusing the movable part with respect to the fixed part. and a support part that is swingably supported in the tracking direction and the tracking direction.

That is, the movable section is constructed by sequentially fitting a substantially quadrangular prism-shaped focusing coil unit 7 and a tracking coil unit 8 to the outside of the bobbin 6 to which the lens 1 is attached, and this movable section is configured to move in the focusing direction and the tracking direction. driven by.

Further, the support section includes a base 11 and a mounting section 13 that is swingably attached to the base 11 via a pair of spring members 12 made of copper alloy. A protrusion 13a formed on the bobbin 6 or the like is fixed to a locking portion 6a formed on the bobbin 6 or the like, and the base 11 is screwed to the yoke 9 of the fixing portion with a screw 14.

Thereby, the movable part is swingably attached to the fixed part.

Further, the yoke 9 of the fixed portion is composed of a pair of cores 9a and an outer yoke 9b, and the magnet 10 is attached to the inside of each outer yoke 9b.

As shown in the figure, the polarity of the upper and lower halves of this magnet 10 is reversed, so that a magnetic field in the direction of arrow C or in the direction of the arrow is formed between this magnet 10 and the core 9a as shown in the figure. be done.

As shown in FIG. 2, the movable portion and the fixed portion as described above are such that each surface of the focus coil unit 7 and tracking coil unit 8 is interposed between the core 9a and the magnet 10.

Further, as shown in FIG. 1, the tracking coil unit 8 has two stages of coil parts each forming the tracking coil 3 at the four corners of a substantially rectangular cylindrical shape. The direction of the spiral is determined so that the current flows in that direction.

That is, this tracking coil unit 3
As shown in the figure, a spiral conductor 3a is formed on one side 5a and the other side 5b of the insulating sheet 5 by an additive method such as plating,
3b is formed, and the conductors 3a and 3b formed on each surface 5a and 5b are connected at their outer peripheral ends, and the conductors 3a and 3 that face each other with the insulating sheet 5 interposed therebetween are connected to each other at their outer peripheral ends.
The conductors 3a and 3b are connected in series through a through hole at each inner peripheral end.

Then, the insulating sheet 5 on which the conductors 3a and 3b connected as described above are formed is bent at the bending part 15 with an insulating paper interposed therebetween.
The conductors 3a and 3b are laminated in a state where they are wound around the J gap and fixed with adhesive to increase rigidity. As a result, a tracking coil unit 8 as shown in FIG. 1 is formed in which the tracking coil 3 is formed on the cylindrical surface.

A tracking control signal (coil current) is supplied to the tracking coil 3 via the spring member 12, thereby generating a magnetic field in a predetermined direction. This magnetic field acts with the magnetic field generated between the core 9a of the fixed part and the magnet 10, and a force is exerted on the tracking coil unit 8 in the tracking direction (direction of arrow B).
The strength and direction of this force are variable depending on the current level and direction of the tracking control signal, so that the movable part is moved so that the laser beam focused by the lens 1 is on-track. is now driven.

On the other hand, the focus coil unit 7 is constructed by forming spiral conductors 2a and 2b on each surface 4a and 4b of an insulating sheet 4 by an additive method or the like, as shown in FIG.
A focus coil unit 7 as shown in FIG. 1 is formed by wrapping the coil around the insulating paper at intervals.

That is, the conductors 2 facing each other with the insulating sheet 4 interposed therebetween
The conductors 2a and 2b are connected to each other at each inner peripheral end via a through hole, and the conductors 2a and 2b on each surface 4a and 4b are connected to each other at each outer peripheral end. As a result, the conductors 2a and 2b are connected in series. Note that the spiral direction of each conductor 2a, 2b is determined so that current flows in the same direction in all of the conductors 2a, 2b, as shown by the arrows in FIG.

When a focusing control signal (coil current) is supplied to the focus coil unit 7 configured as described above via the spring member 12, each of the conductors 2a, 2
A magnetic field in a predetermined direction is generated in the focus coil 2 constituted by b. This magnetic field interacts with the magnetic field generated between the core 9a and the magnet 10 to exert a force on the focus coil unit 7 in the focusing direction (in the direction of the arrow). This allows the distance of the lens 1 to the disk surface to be optimized.

As described above, according to the lens driving device according to this embodiment, the position of the lens 1 with respect to the disk surface is brought into the FIL'S state by supplying control signals to the focus coil unit 7 and the tracking coil unit 8, respectively. can be controlled. Note that the above control signal is
It is obtained by a generally known method and is not particularly limited.

Further, by using a multilayer printed coil as described above to drive the lens 1, it is possible to achieve a reduction in size and weight.

By the way, by using a coil unit 20 in which a coil 21 as shown in FIG. 5 is formed, the movable portion can be rotationally driven in the direction of arrow E in FIG.

That is, in this coil unit 20, as shown by the arrow in FIG.
and connection relationships have been determined.

In this case, as shown in FIG. 6, each conductor 21a, 2
1b all have the same spiral direction, and each surface 22a,
Adjacent conductors 22b are connected at their respective outer peripheral ends. Therefore, currents in opposite directions flow in adjacent conductors.

Note that the pair of conductors 21a and 21b facing each other with the insulating sheet 22 interposed therebetween are connected at each inner peripheral end via a through hole.

When a control signal is supplied via the spring member 12 to the coil unit 20 in which the conductors 21a and 21b are formed in this way, a magnetic field in a predetermined direction is generated in each of the coil parts, and this magnetic field is It interacts with the magnetic field generated between magnet 10 and core 98. As a result, for example, a force in the direction of arrow F acts on one coil portion in FIG. 5, and a force in the direction of arrow G acts on the other coil portion, so that a rotational force is generated as a whole.

Therefore, by using this coil unit 20, the inclination of the laser beam with respect to the disk surface can be corrected,
In addition to being able to prevent the occurrence of crosstalk,
Changes in the transfer function (MTF) of information signal reading can be prevented.

Furthermore, even if the above-described coil unit 20@ is provided in addition to the above-described tracking coil unit 8 and focus coil unit 7, increasing the size can be prevented by configuring these with printed coils.

In addition, when using the above-mentioned coil unit 20, the seventh
By supporting this coil unit 20 with a support member 23 made of an elastic material such as rubber as shown in the figure, it is possible to support driving in any direction by each of the coil units 7, 8, and 20. can.

In addition, in the focus coil unit 7, by reversing the direction of the current in the first layer 7a of this coil unit 7 and the current in the other surface 7b facing this layer 7a, the focus coil unit 7 can be A force acts in the direction of arrow H in Figure 5.

Next, another embodiment according to the present invention will be described using FIG. 8.

The lens driving device according to this embodiment is as shown in FIG.
The lens driving device shown in FIG. 1 is further miniaturized by eliminating the core 9a of the yoke 9, and includes a bobbin 30 to which the lens 1 is attached, a tracking coil unit 31, and a focus coil unit 32. A movable part consisting of a yoke 33 and a fixed part consisting of a magnet 34 is attached to a supporting part as shown in FIG. installed and configured.

Further, since the focus coil unit 32 and the tracking coil unit 31 are provided in close contact with the outer periphery of the substantially prismatic bobbin 30 as shown in the figure, the distance between the pair of outer yokes 33a of the yoke 33 can be made extremely small. I can do it.

In this embodiment, the upper and lower half surfaces of the magnet 34 provided inside the outer yoke 33a are arranged as indicated by the arrow 1. A closed magnetic path in the J direction is formed respectively.

Therefore, the direction of the coil current at the negative side 32A of the focus coil unit 32 and the negative side 32A
The directions of the filter coil currents on the other surface 32B facing the surface 32B are opposite to each other.

In the lens driving device according to this embodiment, the movable part is small and lightweight, and each coil unit 31, 32 is in close contact with the bobbin 30, so that the movable part changes from a low frequency to a high frequency range. Follows well.

Further, it is possible to further reduce the size and weight of this type of device.

(Effects of the Invention) As is clear from the above description, according to the present invention, the lens driving device can be made smaller, lighter, and more efficient, and productivity can also be improved. .

Furthermore, the focus coil and tracking coil can be made at any position and in any winding direction, increasing the degree of freedom in design and production.

[Brief explanation of drawings]

FIG. 1 is an exploded perspective view showing an embodiment of the lens driving device according to the present invention, FIG. 2 is a sectional view taken along the line ■-■ in the assembled state of the lens driving device shown in FIG. A developed view of the tracking coil unit according to the example, FIG. 4 is a developed view of the focus coil unit, FIG. 5 is a perspective view of the coil unit shown in FIG. 6, and FIG. 6 is a developed view of the coil unit shown in FIG. FIG. 7 is a perspective view showing another support member, and FIG. 8 is an exploded perspective view showing another embodiment of the lens driver according to the present invention. 1... Lens, 2... Focus coil, 3...
Tracking coil, 7.32... Focus coil unit, 8.31... Tracking coil unit, 9.33... Yoke, 10.34... Magnet, 11
...Base, 12...Spring member, 13...Mounting part. fl illustrator 3rd

Claims (1)

[Claims] A focusing coil for driving a lens that focuses an information signal collecting laser beam irradiated onto a disk surface on which an information signal is recorded in the optical axis direction of the lens;
a movable part including a tracking coil for driving the lens in the radial direction of the disk; a fixed part forming a magnetic circuit for driving the movable part; In a lens driving device equipped with a supporting part that is swingably attached in an axial direction and a radial direction, a print formed by wrapping the focusing coil and tracking coil with an insulating sheet having a spiral conductor formed on the surface thereof. A lens driving device characterized by comprising a coil.