JPH0750527B2 - Objective lens drive - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention is used for an optical disc device that optically records or reproduces information by projecting a light spot on a disc-shaped recording medium through an objective lens. The present invention relates to an objective lens driving device.

(Prior Art) In the above-mentioned optical disc device, it is necessary to control so that the light spot information track is correctly followed in order to record and reproduce information accurately. For this reason, conventionally, it is known that an objective lens is movably supported in a focusing direction parallel to the optical axis thereof and a tracking direction orthogonal thereto, and is displaced in both directions by an electromagnetic driving means.

For example, Japanese Patent Laid-Open No. 59-221839 discloses a movable member for holding an objective lens, which is composed of four linear elastic supporting members parallel to each other
For example, there is disclosed an objective lens driving device which is connected to a fixed member via a metal wire and is configured to displace a movable member, that is, an objective lens in a focusing direction and a tracking direction by electromagnetic driving means. In an objective lens driving device that displaceably supports a movable member that supports an objective lens using such a metal wire, the metal wire is passed through a rubber tube to serve as a damper in order to reduce the influence of resonance of the metal wire. I try to use it together.

(Problem to be Solved by the Invention) In the above-described conventional objective lens driving device having the linear elastic support member, the thickness of the rubber tube which is the damper member is increased in order to enhance the effect of the linear elastic support member as a damper. It is better to increase the diameter to make the diameter larger. However, if the linear elastic support member is made to have a large diameter, the attachment portion of the movable member and the fixed member becomes large when the end portion is attached to the movable member and the fixed member. Such a large mounting portion of the movable member and the fixed member leads to a large objective lens driving device, and it is desirable to avoid such a situation as much as possible.

An object of the present invention is to solve the above-mentioned contradictory problems and to provide an objective lens driving device capable of enhancing the damper effect of the linear elastic supporting member and downsizing the same.

(Means for Solving the Problems) According to the present invention, a movable member holding an objective lens is connected to a fixed member via a plurality of linear elastic supporting members, and at least the optical axis of the objective lens is provided by a driving unit. In the objective lens driving device configured to be driven in a direction and a direction orthogonal thereto, the linear elastic support member includes a large diameter portion of the central member and a small diameter portion of the connecting portion, and It is characterized in that the movable member and the fixed member are connected to each other.

(Operation) In such an objective lens driving device of the present invention, the damper effect can be enhanced by forming the central portion of the linear elastic support member with the large diameter portion, and both ends are formed with the small diameter portion. Thus, the connecting portion between the movable portion and the fixed portion for attaching the linear elastic support member can be made small, and therefore the entire objective lens driving device can be made compact.

Further, even if the linear elastic support member bends by separating the step portion at the boundary between the large-diameter portion and the small-diameter portion of the linear elastic support member from the connecting portion of the movable member and the fixed member, the step portion is connected to the connecting portion. Since the linear elastic support member is not subjected to an undesired force, the optical axis of the objective lens is not undesirably tilted.

(Embodiment) FIGS. 1 to 3 are perspective views showing the configuration of an embodiment of the objective lens driving device of the present invention. The objective lens 1 is fixed to a lens holder 2A of a movable member 2 made of an integrally molded plastic body. In this example, the objective lens 1 is composed of a plano-convex SELFOC lens. The movable member 2 has a frame 2B having a rectangular cross section so as to surround the lens holder 2A, and the lens holder 2A stands up from a bottom wall 2C of this frame. Supporting portions 2D to 2G for supporting the linear elastic supporting members 3A to 3D are formed on side walls of the frame 2B facing each other. One supporting portion 2G is not visible in FIGS. The print coil 4 is fixed to the outer peripheral surface of the frame 2B by adhesion. In the development view of FIG. 3, the print coil 4 is shown in a state of being extended in one plane. The print coil 4 includes a flexible insulating sheet and four tracking coil portions.
4A to 4D are provided, and each coil has 2
The coils of layers are stacked with an insulating film interposed. These coils are electrically connected to each other, and both terminals are connected to the lands 4E and 4F. Frame the print coil 4
In order to perform positioning when mounting on the outer peripheral surface of 2B, a projection 2H is formed on the lower part of one side surface of the frame 2B, and a recess 4G formed in the print coil 4 is fitted therein. A focusing coil 5 is further wound around the print coil 4. The terminal lead wires of the focusing coil 5 are connected to the lands 4H and 4I provided on the print coil 4.
The movable member 2 is configured in this manner, and the elastic support members 3A to
It connects to the fixing member via 3D.

The fixing member 16 includes a base 11 made of an integrally molded body of magnetic material. The base 11 has a bottom portion 11A, and four yoke portions 11B to 11E, which stand vertically upward from the bottom portion, are integrally formed. Permanent magnets 12A and 12B are fixed to the inner surfaces of the yoke portions 11B and 11C. In this example, these yoke parts
Grooves 11F and 11G are formed on the inner surfaces of 11B and 11C, and the permanent magnets 12A and 12B are magnetically applied to the yoke portions 11B and 11C.
After being adsorbed at a predetermined position, an adhesive is poured into the grooves 11F and 11G to fix the permanent magnet to the yoke portion. With such a configuration, the permanent magnet can be accurately positioned and fixed to the yoke portion, and the assembly becomes easy, which is particularly suitable for automatic assembly by a machine.

The insulating plate 13 and the printed board 14 are fixed to the outer surface of the yoke portion 11C of the base 11 of the fixing member 16 with screws 15. A pair of protrusions 13A and 13B are provided on the inner surface of the insulating plate 13, and a yoke portion 11C is fitted between them to position them. Further, grooves 13C to 13F into which the ends of the elastic support members 3A to 3D are fitted are formed on both side surfaces of the insulating plate 13, and grooves 14A to 14D having the same shape and dimensions are formed at positions corresponding to the side surfaces of the printed board 14. Form. As shown clearly in FIG. 2, a substantially ring-shaped protrusion 11H is formed on the lower surface of the bottom 11A of the base 11, the tip end surface of which is a curved surface, and the objective lens driving device is supported to support a disk-shaped recording medium. The carriage that can be driven in the radial direction is rotatably mounted. A part of this ridge 11H is cut out together with the base bottom 11A to form an optical path. In this way, the fixing member 16 is configured.

As described above, the movable member 2 and the fixed member 16 are connected via the linear elastic support members 3A to 3D. The connection state and the structure of the elastic support member are shown in FIGS. Although the elastic support member 3A is shown in these drawings, the configuration and connection state of the other elastic support members are the same. Elastic support member 3A
Is a metal wire 3a made of phosphor bronze with a diameter of 0.1 to 0.2 mm.
And a damper member 3b made of butyl rubber integrally formed on the outer periphery thereof. Metal wire like this
When the elastic support member 3A in which the 3a and the damper member 3b are integrated is used, the vibration energy of the metal wire is transmitted to the damper member and is absorbed there, so that undesired resonance can be prevented.
The damping action can be effectively performed. In this example, the damper member 3b has a large diameter portion 3b-1 at the center and a small diameter portion 3b-at both ends.
2, 3b-3, and the diameter of the large diameter portion is 1.3 mm and the diameter of the small diameter portion is 0.6 mm. Both ends of the metal wire 3a project outward from the small diameter portions 3b-2 and 3b-3, respectively. The groove 2D-is formed in the support portion 2D formed on the side surface of the frame 2B of the movable member 2.
1 is formed. As shown in FIG. 4B, this groove 2D-1 is
It has an introduction part 2D-2 and a storage part 2D-3 having a substantially circular cross section, and the height of the introduction part 2D-2 is the small diameter part 3b-2 of the damper.
The diameter of the storage portion 2D-3 is set to 0.5 mm, which is slightly smaller than the diameter of the storage portion 2D-3, and is set to 0.6 mm, which is equal to the diameter of the small diameter portion 3b-2. Also,
The entrance of the introduction section 2D-2 is tapered. Therefore, when fitting the small-diameter portion 3b-2 into the groove 2D-1, the small-diameter portion is pushed into the introduction portion 2D-2 and crushed slightly,
Up to the storage section 2D-3 will be inserted. The tip of the metal wire 3a projects from the supporting portion 2D and is connected to the land 4H of the print coil 4 by the solder 17, and the conducting wire 5a at one end of the focusing coil 5 is also connected thereto. In this way, the land 4H in which the metal wires of the elastic supporting members 3A and 3B are formed in the margin of the insulating sheet of the print coil 4 is formed.
And 4I to fix the elastic member by soldering and to electrically connect the focusing coil 5 to a predetermined conductor portion of the printed board through the metal wire.

The other end of the elastic support member 3A is inserted into the grooves 13C and 14A formed on the side edges of the insulating plate 13 and the printed circuit board 14, and this groove is continuous with the introduction portions 13C-1 and 14A-1. It has storage parts 13C-2 and 14A-2. Introductory part 13C
-1,14A-1 has a height of 0.5 mm, and the small diameter part 3b of the elastic support member
-3 is slightly smaller than the diameter of 0.6 mm, but the storage part 13C
The diameter of −2, 14A-2 is 0.8 mm, which is larger than the diameter of the small diameter portion 3b-3. Therefore, there is a gap between the small diameter portion and the accommodating portion when the small diameter portion 3b-3 of the elastic support member is inserted into the accommodating portions 13C-2 and 14A-2 of the grooves 13C and 14A. Is filled with an adhesive 18 having viscoelastic properties. The end of the metal wire 3a protruding from the surface of the printed board 14 is soldered to the conductor portion 14A-3 formed on the printed board.
Bind by.

As shown in FIG. 4, in this example, the step portion 3b-4 between the large diameter portion 3b-1 of the damper member 3b of the elastic support member 3A and the one small diameter portion 3b-2 is separated from the support portion 2D. I am letting you. With this configuration, even when the elastic support member 3A is bent during operation, the step portion 3b-4 does not contact the support portion 2D, so an undesired force is applied to the metal wire 3a via the damper member 3b. There is no fear, and there is no fear that the optical axis of the objective lens is undesirably tilted. This is particularly effective when the length of the damper member 3b varies. Moreover, since the step portion 3b-5 between the large diameter portion 3b-1 and the other small diameter portion 3b-3 and the insulating plate 13 are connected by the adhesive 18 as described above, a damping action is obtained. Will be improved. For this purpose, it is preferable to use a soft adhesive as the adhesive 18, for example, a silicon-based ultraviolet curable adhesive.

Next, an assembly procedure for connecting the movable member 2 and the fixed member 16 described above via the linear elastic support members 3A to 3D will be described. First, using a suitable jig, the movable member 2 and the fixed member 16
After arranging and in a predetermined positional relationship, the small diameter portion of the elastic supporting member is pushed into the grooves of the supporting portions 2D to 2G of the movable member 2 and the grooves formed on the side edges of the insulating plate 13 of the fixed member 16 and the printed circuit board 14 are formed. Push it into 13C-13F and 14A-14D. Also at this time, the elastic supporting member is held at a predetermined position by using an appropriate jig. Next, it is soldered to the lands 4E, 4F, 4H, 4I formed on the insulating sheet of the printed coil 4 at one end of the metal wire 3a. Further, after the other end of the metal wire 3a is soldered to the conductor portion of the printed board 14, between the storage portion of the groove formed in the side edge of the insulating plate 13 and the printed board 14 and the small diameter portion of the damper member. Pour the adhesive into the gap and bond. At this time, the stepped portion between the large diameter portion and the small diameter portion of the damper member is also connected to the insulating plate 13 by the adhesive. In this way, the movable member 2 and the fixed member 16 can be connected easily and accurately via the linear elastic support members 3A to 3D.

The present invention is not limited to the above-mentioned embodiments, but various modifications can be applied. For example, in the above-mentioned embodiment, the groove for supporting the elastic supporting member has the introducing portion and the accommodating portion having a size larger than this, but as shown in FIG. 5, the metal wire 31a of the elastic supporting member 31 is removed. Introducing part slightly smaller than the diameter of the small diameter part 31b-1 of the surrounding damper member 31b.
It is also possible to have a storage portion 32b having the same size as 32a. Further, as shown in FIG. 6, a V-shaped groove 42 having a dimension corresponding to the diameter of the metal wire 41a of the elastic support member 41 may be used. The elastic support member can also be positioned by such a V-shaped groove 42, and after positioning,
The elastic support member can be fixed to the movable member or the fixed member by solder or an adhesive.

Further, in the above-described embodiment, the linear elastic support member is composed of the metal wire and the damper member integrally connected to the periphery thereof, but the elastic support member or the metal wire in which the metal wire is inserted into the rubber tube is used. It is also possible to use an elastic support member which is wound in a coil shape and whose inside is integrally filled with a damper member.

(Effect of the Invention) According to the above-described objective lens driving device of the present invention, the central portion has a large diameter (for example, 31b in FIG. 5 and the damper member in FIG. 6), and the connecting portion has a small diameter (for example, the fifth diameter). 31b-1 and 6 in the figure
By using the linear elastic support member which is 41a) in the figure,
It is possible to provide an objective lens driving device which can enhance the damper effect of the linear elastic support member and has a small connecting portion between the movable member and the fixed member.

Further, since the stepped portion formed at the boundary between the large diameter portion and the small diameter portion is separated from the end surface of the connecting portion of the movable member and the fixed member, the step portion does not contact the end surface of the connecting portion even if the linear elastic support member bends. Since there is no contact and no undesired force is applied to the linear elastic support member, the optical axis of the objective lens does not undesirably tilt.

[Brief description of drawings]

1 to 3 are perspective views showing the construction of an embodiment of the objective lens driving device of the present invention, and FIGS. 4A to 4C are sectional views showing the elastic support member and its combined state, and FIG. And FIG. 6 is a perspective view showing another shape of the groove for positioning the elastic supporting member of the objective lens driving device of the present invention. 1 ... Objective lens, 2 ... Movable member 2A ... Lens holder, 2B ... Frame 2D-2G ... Supporting part, 3A-3D ... Elastic support member 4 ... Print coil 5 ... Focusing coil 11 ... Base, 11B to 11E ...... Yoke part 13 ...... Insulation plate, 14 ...... Printed circuit board 16 ...... Fixing member 2D-1,13C to 13F, 14A to 14D ...... Groove 3a ...... Metal wire, 3b ...... Damper member 17,19 ... Solder, 18 ... Adhesive

Claims (2)

[Claims] 1. A movable member holding an objective lens is connected to a fixed member via a plurality of linear elastic support members, and the objective lens is driven at least in the optical axis direction and in a direction orthogonal thereto by a driving means. In the objective lens driving device configured as described above, the linear elastic support member includes a central portion having a large diameter portion and a connecting portion having a small diameter portion, and the small diameter portion connects the movable member and the fixed member. An objective lens driving device, characterized in that it is connected to a section. 2. The objective lens driving device according to claim 1, wherein the stepped portion formed by the large diameter portion and the small diameter portion of the linear elastic support member is an end surface of the connecting portion. An objective lens driving device characterized in that it is separated from the.