JPH03113732A - Optical system drive device - Google Patents

Abstract

PURPOSE:To reduce cost by forming an inner yoke and an outer yoke into one body together with a fixed member through a connection member. CONSTITUTION:The inner yoke 7 and the outer yoke 6 are connected to both ends of a base 5 as being integrated into one body with it. The inner yoke 7 and the outer yoke 6 are connected through a connection part 8. Since the connection part 8 exists between the inner yoke 7 and the outer yoke 6 in this way, the leakage magnetic field of a recording/reproducing medium side is small, and therefore, an adverse influence is not exerted at the time of the recording and the reproduction of a magneto-optical recording medium. Since the outer yoke 6 and the inner yoke 7 and formed integrally, the precision of an interval between both is easy to produce, and the variance of the magnetic flux density of a magnetic gap becomes small as well. The base of the optical system drive device and plural yokes can be made of sheet steel integrally, and the number of parts becomes small, and the cost can be made inexpensive.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an optical system drive device in an apparatus for optically recording or reproducing information.

[Conventional technology]

As a method for molding the base and yoke of an optical system drive device in a device that optically records or reproduces information, for example, Japanese Utility Model Application Publication No. 187025/1983 discloses a magnet support mechanism for an optical pickup.

As shown in FIG. 4, the magnet support mechanism of the optical pickup described in this publication movably supports an objective lens 21 held by a holding member 20 above a base 23 via a leaf spring 22. is integrally formed from a sheet metal, and includes a coil 24 that operates together with the objective lens 21, and yokes 26a and 26b of a magnet 25 that is disposed opposite the base 2.
It is bent from 3 and formed into one piece.

In the figure, 27 indicates a medium, 28 a light source, and 29 a prism.

However, when the magnet support mechanism of the optical pickup is applied to an optical system drive device having a configuration in which two magnetic circuits are arranged symmetrically, if the distance between the inner yokes in the two magnetic circuits is small, It is impossible to bend the inner yoke from the base and form it in one piece,
Or the work becomes complicated or difficult.

Therefore, as a means to solve this problem, in configuring an optical system drive device in which the two magnetic circuits are arranged symmetrically, magnets 33 and 34 are attached to the base 30 as shown in FIG. Pair of outer yokes 31.3
A pair of inner yokes 36 and 37 are separately set up to face the base 35, and the base 35 of the inner yokes 36 and 37 is connected to the outer yoke 3.
A technique for constructing a base 30 by incorporating it into a base 30 of 1.32 mm is described in Japanese Patent Laid-Open No. 63-211133.

[Problem to be solved by the invention]

However, the optical system driving device of the prior art has a structure in which two magnetic circuits are arranged symmetrically (the optical system driving device shown in FIG. 5), but the optical system driving device of the prior art has a structure in which the yoke is bent from the base of the former. Although the problem with the optical system drive device if (the optical system drive device shown in FIG. 4) can be solved, it requires forming the outer yoke and inner yoke separately and assembling both, which increases the manufacturing cost and the assembly time. had disadvantages such as high cost.

Therefore, the present invention was developed in view of the structural disadvantages of optical system drive devices in the conventional technology, and is an optical system such as an objective lens that can reduce the number of parts and reduce assembly cost. The purpose is to provide a drive device.

[Means and effects for solving the problems] The optical system drive device of the present invention includes a movable member that holds an optical member that is displaceable with respect to a fixed member, a drive coil disposed on the movable member, and a drive coil disposed on the movable member. An optical system drive device comprising first and second yokes constituting a magnetic circuit that generates a magnetic field that cooperates with a coil, wherein the fixing member and the first and second yokes are integrally formed, and the first and second yokes are integrally formed. The first yoke has one end connected to the fixed member and the other end connected to the second yoke via a connecting member.
The structure is constructed by being connected to the yoke of the yoke, which can reduce the number of parts and the cost of assembly.

〔Example〕

Embodiments of the optical system driving device of the present invention will be described below with reference to the drawings.

(First Embodiment) FIGS. 1 and 2 show a first embodiment of the optical system drive device of the present invention. FIG. 1 is a perspective view of the optical system drive device, and FIG. 2 is a front view of the inner and outer yoke parts. It is.

Thus, in FIG. 1, the objective lens 1 is fixed to a movable member 4 around which a focusing coil 2 is wound and a tracking coil 3 is bonded.

The base 5 is provided with an outer yoke 6 and an inner yoke 7, and a magnet 9 is bonded to the inside of the outer yoke 6.
! ! It forms a magnetic circuit.

A fixed member 10 is fixed to one of the outer yokes 6, and the fixed member 10 and the movable member 4 are arranged so as to correspond to each other.
Round holes 12 and 13 are formed, and the ends of four metal wires 11 are inserted into the holes 12 and 13 and fixed with adhesive.

The movable member 4 is supported by four metal wires 11 with respect to the fixed member 10 so as to be movable in the focusing direction and the tracking direction, so when a current is passed through the focusing coil 2 or the tracking coil 3, electromagnetic interaction with the magnet 9 occurs. As a result, a driving force is generated and the movable member 4 moves in each direction.

As shown in FIG. 2, the yoke portion in the configuration of such an optical system drive device has a base 5 made of iron sheet metal, and an outer yoke 6 which is bent and connected to both ends of the base 5. At the other end of the outer yoke 6, an inner yoke 7 is bent into a U-shape and integrally connected to the other end of the outer yoke 6 via a connecting portion 8.

That is, the pair of inner and outer yokes 6.7 are integrally formed with the base 5.

The movable member 4 is assembled to the base 5 from below.

Therefore, according to the optical system drive device having the above configuration, the following effects can be obtained.

(2) Since the position of the movable member 4 when it moves upward in the focus direction is determined by the movable member 4 and the connecting portion 8, the positional accuracy of the movable member 4 relative to the base 5 can be easily achieved.

(2) Since there is a connecting portion 8 between the inner yoke 7 and the outer yoke 6, the leakage magnetic field on the recording/reproducing medium side is small, so that it does not have an adverse effect on recording and reproducing the magneto-optical recording medium.

(2) Since the outer yoke 6 and the inner yoke 7 are integrally formed, it is easy to achieve accurate spacing between them, and variations in magnetic flux density in the magnetic gap are also reduced.

(Second Embodiment) FIG. 3 is a perspective view of a yoke portion showing a second embodiment of the present invention.

As for the yoke portion in this embodiment, similarly to the first embodiment, the outer yoke 6 and the inner yoke 7 are bent into a U-shape and connected to one end of the outer yoke 6 via the connecting portion 8. The base 5 is integrally formed from the other end of the outer yoke 6, and the pair of inner and outer yokes 6.7 are integrally processed with the base 5 from an iron sheet metal. .

Therefore, in this embodiment, the base 5 and the outer yoke 6 are connected to each other at the lower end of the outer yoke 6, whereas in the first embodiment, the base 5 and the outer yoke 6 are connected to each other at the lower end of the outer yoke 6. The base 5 is integrally formed by twisting and bending the vicinity of the connecting portions 5a and 5b from the sides, and connecting the base 5 horizontally in a plane parallel to a plane perpendicular to the upright surface of the outer yoke 6.

Therefore, as shown in FIG. 3, the first
The base 5 in this embodiment extends to one side of the inner and outer yokes 6 and 7, which are arranged in symmetrical positions, but the base 5 in this embodiment extends to one side of the inner and outer yokes 6 and 7, which are arranged in symmetrical positions.
．． It extends to both sides of 7.

The rest of the structure is the same as that of the first embodiment, and specific illustrations and explanations thereof are omitted, but as mentioned above, the bases 5 on both sides are connected to the outer yoke 6 at It is a side part of the outer yoke 6, and the continuous parts 5a and 5b
The position is not limited to the illustrated position, and any position in the height direction of the outer yoke 6 can be selected.
Structurally, the metal wire 11 supporting the movable member 4 with respect to the fixed member 10 is disposed across the base 5 between the upper and lower sides thereof.

That is, according to the configuration of this embodiment, the height dimension of the entire optical system driving device can be reduced by setting the position where the base 5 is connected to the outer yoke 6 at any position in the height direction of the outer yoke 6. It has the advantage of being configurable.

Regarding other effects, it is possible to obtain the same effects as in the first embodiment.

〔Effect of the invention〕

According to the present invention, the base of the optical system drive device and the plurality of yokes can be integrally molded from a sheet metal, and the number of parts can be reduced (and the cost can be reduced).

[Brief explanation of drawings]

1 and 2 show a first embodiment of the optical system driving device of the present invention, FIG. 1 is a perspective view of the optical system driving device, FIG. 2 is a front view of the inner and outer yoke parts, and FIG. 3 is a main body. A perspective view of a yoke portion showing a second embodiment of the invention, and FIGS. 4 and 5 are explanatory diagrams showing the configuration of a conventional optical system driving device. 1... Objective lens 2... Focus coil 3... Tracking coil 4... Movable member 5... Base 6... Outer yoke 7... Inner yoke 8... Connecting portion 9...・Magnet 10...Fixing member 11...Metal wire

Claims (1)

[Claims] (1) A movable member that holds an optical member that is displaceable with respect to a fixed member, a drive coil disposed on the movable member, and a first and second and a second yoke, wherein the fixing member and the first and second yokes are integrally formed, and the first yoke has one end connected to the fixing member, and the other An optical system driving device characterized in that the end thereof is connected to the second yoke via a connecting member.