JPH0765392A - Support spring and optical element drive using the same - Google Patents

Abstract

(57) [Abstract] [Purpose] The metal spring is not deformed by the molding pressure when molding the damping rubber, and it is stable by using this support spring and high-order resonance. A controllable optical element driving device is provided. An objective lens holder 100 to which an objective lens 105 is fixed is mounted on an actuator base 91 by four support springs 50 formed by coating a metal wire spring with a cylindrical damping rubber so that a part of the spring is exposed. It is movably supported. Focusing coil 1
06 and the electromagnetic force generated by the tracking coil 107 and the electromagnetic action of the permanent magnets 95 and 96, the outer yokes 92 and 93, the inner yokes 97 and 98, the upper yokes 120 and 121, and the magnetic circuit formed by the actuator base 91. The objective lens holder 100 is driven in the focusing direction and the tracking direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a support spring and an optical element driving device using the support spring, for example, a support spring for movably supporting an optical head or the like in an optical disk device,
The present invention relates to an optical element driving device that moves an optical head or the like supported by this support spring.

[0002]

2. Description of the Related Art For example, an optical disk device is provided with an optical element driving device for moving an optical head provided with an objective lens in a focusing direction and a tracking direction with respect to a disk surface. In this optical element driving device, the optical head is movably supported by the support spring. The support spring is a metal spring covered with a viscoelastic body (damping rubber) for damping the vibration of the metal spring generated during movement. That is, it is formed by pouring liquid rubber into a mold in which a metal spring is fitted, curing the rubber, and then removing the mold. However, in such coating molding, since the metal spring is bent by the flow pressure of the rubber, the metal spring is retained in the hardened rubber (damping rubber) while being deformed. Therefore, in order to prevent such deformation of the metal spring, a support spring disclosed in Japanese Patent Laid-Open No. 4-251443 has been conventionally proposed. In this support spring, the metal spring has a plurality of protrusions that project perpendicularly to the extending direction, and the damping rubber is coated so that the tips of the protrusions are exposed. This support spring prevents the metal spring from being deformed by the molding pressure by pressing the tip of the protrusion with a molding die during molding of the damping rubber.

[0003]

However, in the conventional support spring having the protrusion, higher-order resonance of the spring having the protrusion A as a node as shown in FIG. 13 is likely to occur. Therefore, when trying to control the driven body (optical head) supported by such a support spring, the control becomes unstable due to the occurrence of the resonance as described above. On the other hand, in the biaxial objective lens actuator that supports the objective lens of the optical disc by using such a support spring, focusing control and tracking control are likely to become unstable due to the resonance, which causes servo misalignment.

Therefore, a first object of the present invention is to provide a support spring in which the metal spring is not deformed by the molding pressure at the time of molding the damping rubber and the higher resonance is less likely to occur. . A second object of the present invention is to provide an optical element driving device in which higher-order resonance is less likely to occur and stable control is possible.

[0005]

According to a first aspect of the present invention, a supporting spring includes an elongated metal spring and a damping rubber that covers the periphery of the metal spring and is provided with a plurality of recesses for exposing the metal spring. In order to achieve the first object. According to a second aspect of the present invention, there is provided a holder for fixing the optical element, an elongated metal spring, and a damping rubber which covers a periphery of the metal spring and has a plurality of recesses for exposing the metal spring. The second objective is achieved by providing the optical element driving device with a plurality of displaceable support springs and a drive means for moving the holder supported by the support springs in the displaceable direction.

According to the third aspect of the invention, the first object is achieved by providing the support spring with an elongated metal spring and a damping rubber that covers only both ends of the metal spring in the longitudinal direction. According to a fourth aspect of the present invention, a holder to which the optical element is fixed, a plurality of support springs formed by coating damping rubber only on both ends of the elongated metal spring in the longitudinal direction, and displaceably supporting the holder, are provided. By providing the optical element drive device with a drive means for moving the holder supported by the support spring in the displaceable direction,
Achieve the purpose of.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the support spring according to the present invention will be described in detail below with reference to FIGS. FIG. 1 shows the shape of the support spring 10 according to the first embodiment. The support spring 10 is composed of a metal leaf spring 11 and a damping rubber 12 covered with the metal leaf spring 11. The metal leaf spring 11 is composed of an elongated deforming portion 15 and fixing portions 13 and 14 formed in a flat plate shape at both ends thereof.
The metal leaf spring 11 is configured so that the fixing portions 13 and 14 are fixed at predetermined positions of the driving device, and the deforming portion 15 elastically deforms to function as a spring. The damping rubber 12 is molded so as to cover the deformed portion 15 and a part of the fixed portions 13 and 14, and a plurality of recesses 16 and 17 exposing a part of the deformed portion 15 form a pair vertically. Is formed.

FIG. 2 shows a molding die for molding the damping rubber 12, and FIG. 3 shows a shape of a dug formed in the molding die. As shown in FIG. 2, the forming die is composed of an upper die 18 and a lower die 19, and a dug 20 is formed in each of these. As shown in FIG. 3, the dug 20 includes spring holding portions 23 and 24 formed to hold the fixing portions 13 and 14 of the metal leaf spring 11, and 3 formed therebetween.
It is composed of one concave portion 25, 26, 27 and two convex portions 28, 29 corresponding to the concave portions 16, 17 of the damping rubber 12.

FIG. 4 shows a sectional shape in a state where the upper mold 18 and the lower mold 19 are combined. To cover the metal leaf spring 11 with the damping rubber 12, the upper mold 18
The metal leaf spring 11 is vertically sandwiched between the lower mold 19 and the lower mold 19, and a liquid rubber 21 is poured from a rubber injection port 30 formed in the upper mold 18, as shown in FIG. Then, when the rubber 21 is cured, the upper mold 18 and the lower mold 19 are removed. Metal leaf spring 11
Are fixed parts 13 and 1 in the state of being sandwiched vertically.
The deformable portion 15 is supported by the two convex portions 28 and 29 by the spring holding portions 23 and 24 of the dug portion 20.
By the support by the convex portions 28 and 29, the deformation portion 15 is prevented from being deformed by the flow pressure of the rubber 21.

FIG. 5 shows a support spring 40 according to the second embodiment.
Is represented. The same components as those in the first embodiment are designated by the same reference numerals, and detailed description thereof will be appropriately omitted. The same applies to the following embodiments. The support spring 40 according to the present embodiment includes the damping rubber 4
Two concave portions 43, 44 and 45 are alternately provided on the upper surface side and the lower surface side. As in the case of the first embodiment, when the recesses are aligned on the upper surface (the surface corresponding to the upper mold 18 of the molding die) and the lower surface (the surface corresponding to the lower mold 19), the upper mold 18 and the lower mold 19 are matched. Since the metal leaf spring 11 can be sandwiched between the convex portions 28 and 29, the reliability of holding is good. However, since the damping rubber 12 has a shape divided in the longitudinal direction, the recessed portion 2 is formed during rubber molding.
Since the constricted portions (convex portions 28 and 29) formed due to Nos. 5 and 26 have poor fluidity, it is necessary to provide a plurality of rubber inlets 30 as shown in FIG.

In this embodiment, since the recesses 43, 44 and 45 of the damping rubber 42 are not aligned on the upper surface and the lower surface,
The cross-sectional area in which rubber flows is wide enough, and the injection port may be one place. FIG. 6 shows a support spring 50 according to the third embodiment. The support spring 50 is formed by coating a metal wire spring 51 with three cylindrical damping rubbers 52, 53 and 54. FIG. 7 shows the shape of the dug 55 in the molding die for molding the damping rubber 52. Semi-cylindrical recesses 56, 57 and 58 for molding the damping rubbers 52, 53 and 54, respectively, are formed in the molding die of this embodiment, and at the time of molding, metal wires are formed in the grooves 59 formed between them. The spring 51 is supported.

FIG. 8 shows a support spring 60 according to the fourth embodiment.
Is represented. The support spring 60 is formed by alternately arranging the metal wire spring 51 on the recesses 62, 63, 63, as in the second embodiment.
A cylindrical damping rubber 61 having 64 formed thereon is covered. The method of molding the damping rubber 61 is the same as that of the above-mentioned embodiment. FIG. 9 shows a support spring 70 according to the fifth embodiment. This support spring 70
Is obtained by covering only the end of the deformable portion 15 of the metal leaf spring 11 with damping rubbers 72 and 73.

FIG. 10 shows a change in shape when the metal leaf spring 11 is bent by vertically shifting both ends. As shown in the figure, the metal leaf spring 11 has the largest bending stress at both end portions 74 and 75 covered with the damping rubbers 72 and 73, that is, the largest curvature, and the central portion 7
At 6, the curvature is zero. For example, even when the entire deforming portion 15 of the metal leaf spring 11 is covered with the damping rubber, the damping rubber is largely deformed at both ends thereof and is not so deformed at the center. Therefore, the support spring 70 according to the present embodiment.
Then, only the both ends of the metal leaf spring 11 should have the damping rubber 7
Sufficient damping effect can be obtained by coating with 2, 73. Further, when the damping rubbers 72, 73 are molded, the deforming portion 15 of the metal spring 11 is held by the molding die, so that it is prevented from being deformed by the flow pressure of the rubber. FIG. 11 shows
The support spring 80 according to the sixth embodiment is shown.
The support spring 80 according to the present embodiment is formed by covering both ends of the metal wire spring 51 with cylindrical damping rubbers 81 and 82 for the same reason as in the fifth embodiment.

Next, an embodiment of the objective lens actuator of the optical disk device using the support spring formed as described above will be described. FIG. 12 shows an external configuration of the objective lens actuator 90 according to the present embodiment. The objective lens actuator 90 includes an upright wall portion 91a.
And an L-shaped actuator base 91 including a bottom surface portion 91b. The bottom surface 91b of the actuator base 91 has two outer yokes 92, 9
3 is fixed, and permanent magnets 95 and 96 are adhered to the inner surfaces of the outer yokes 92 and 93 so as to face each other.

Inside the permanent magnets 95, 96, inner yokes 97, 98 having a smaller width than the outer yokes 92, 93 are provided.
It is arranged. The lower ends of the inner yokes 97 and 98 are fixed to the actuator base 91. An objective lens holder 100 as a driven body is arranged between the permanent magnets 95 and 96. This objective lens holder 10
As shown in FIG. 0, through holes 101 and 102 through which the inner yokes 97 and 98 are inserted in a non-contact manner are formed.
Although not shown, a cylindrical through hole is also formed between them so as to vertically penetrate therethrough, and the objective lens 105 is held so as to close the upper end opening of the through hole.

A focusing coil 106 for driving the objective lens holder 100 in the focusing direction is wound around the outer circumference of the objective lens holder 100.
Two tracking coils 107 for driving the objective lens holder 100 in the tracking direction are attached to the front and rear surfaces facing the permanent magnets 95 and 96, respectively. In addition, the objective lens holder 100 is formed with fixing portions 110, 111, 112, and 113 that project to the left and right. This fixed portion 110, 111, 112,
Between the 113 and the upright wall portion 91a of the actuator base 91, the end portions of the metal wire springs 51 are fixed in fixing holes formed in the fixing portions 110, 111, 112, 113 and the upright wall portion 91a, respectively. Two support springs 50 are provided. The objective lens holder 100 uses the support springs 50 to allow the bottom surface portion 91 of the actuator base 91 to be supported.
It is supported so as not to contact b and to be movable in the focusing direction and the tracking direction.

Although not shown, the bottom surface portion 91b includes
A circular hole is formed at a position facing a lower end opening of a cylindrical through hole (not shown) formed in the objective lens holder 100, and a luminous flux of laser light incident from above the objective lens 105 is transmitted to the actuator base 91. It is designed to be transmitted downward. The laser light transmitted downward is applied to the surface of the optical disc by an optical system (not shown) such as a triangular prism. Also, upper yokes 120 and 121 are attached between the upper ends of the outer yoke 92 and the inner yoke 97 and between the upper ends of the outer yoke 93 and the inner yoke 98, respectively, as indicated by arrows. It has become. By the permanent magnet 95, the outer yoke 92, the upper yoke 120, the inner yoke 97 and a part of the bottom surface portion 91b, and the permanent magnet 96, the outer yoke 93, the upper yoke 121, the inner yoke 98 and a part of the bottom surface portion 91b, Front and rear focusing coil 1
Two magnetic circuits are formed so as to surround 06 and the tracking coil 107.

The objective lens holder 100 controls the current flowing through the focusing coil 106 and the tracking coil 107 to generate electromagnetic force and the constant magnetic field generated by the permanent magnets 95 and 96 to cause a focusing direction. Alternatively, the driving is controlled in the tracking direction. In this embodiment, the objective lens holder 100
Although the support spring 50 according to the third embodiment is used as the support spring for supporting the, the support spring according to another embodiment may be used.

[0019]

According to the first aspect of the present invention, the metal spring is not provided with a projection, and the damping rubber is provided with a recess for exposing the metal spring so that the metal spring is held by the molding die when the damping rubber is molded. Therefore, it is possible to prevent the metal spring from being deformed by the pressure during molding. Further, higher-order resonance of the spring having the protrusion as a node is less likely to occur.
According to the invention as set forth in claim 3, in addition to the above effect, it is possible to obtain the effect that the material of the damping rubber can be reduced. According to the second and fourth aspects of the invention, since the optical element driving device is configured by using the support spring in which higher-order resonance is hard to occur, stable drive control is possible.

[Brief description of drawings]

FIG. 1 is a perspective view showing a support spring according to a first embodiment of the present invention.

FIG. 2 is a perspective view showing a molding die for molding the damping rubber of the support spring.

FIG. 3 is a perspective view showing a shape of a dug formed in the molding die.

FIG. 4 is a sectional view of the same molding die.

FIG. 5 is a perspective view showing a support spring according to a second embodiment of the present invention.

FIG. 6 is a perspective view showing a support spring according to a third embodiment of the present invention.

FIG. 7 is a perspective view showing a molding die for molding the damping rubber of the support spring.

FIG. 8 is a perspective view showing a support spring according to a fourth embodiment of the present invention.

FIG. 9 is a perspective view showing a support spring according to a fifth embodiment of the present invention.

FIG. 10 is an explanatory view showing a shape change when the metal leaf spring in the support spring of the present invention is bent by vertically shifting both ends thereof.

FIG. 11 is a perspective view showing a support spring according to a sixth embodiment of the present invention.

FIG. 12 is a perspective view showing an external configuration of an objective lens actuator according to an embodiment of the present invention.

FIG. 13 is an explanatory diagram showing a state in which a conventional support spring causes high-order resonance.

[Explanation of symbols]

10, 40, 50, 60, 70, 80 Support spring 11 Metal plate spring 12, 42, 52, 53, 54, 61, 72, 73, 8
1, 82 Damping rubber 13, 14 Fixed part 15 Deformed part 16, 17, 43, 44, 45, 62, 63, 64 Recessed part 90 Objective lens actuator 91 Actuator base 92, 93 Outer yoke 95, 96 Permanent magnet 97, 98 Inside Yoke 100 Objective lens holder 101, 102 Through hole 105 Objective lens 106 Focusing coil 107 Tracking coil 120, 121 Upper yoke

Claims (4)

[Claims] 1. A support spring, comprising: an elongated metal spring; and a damping rubber which covers the periphery of the metal spring and has a plurality of recesses for exposing the metal spring. 2. A holder for fixing an optical element, an elongated metal spring, and a damping rubber which covers the periphery of the metal spring and is provided with a plurality of recesses for exposing the metal spring, and the holder is displaced. An optical element driving device comprising: a plurality of support springs that are supported so that the holder is supported by the support springs; and a driving unit that moves the holder in a displaceable direction. 3. A support spring comprising an elongated metal spring and a damping rubber that covers only both ends of the metal spring in the longitudinal direction. 4. A holder to which an optical element is fixed, a plurality of support springs formed by coating damping rubber only on both ends of an elongated metal spring in the longitudinal direction, and a plurality of support springs for displaceably supporting the holder, and the support springs. An optical element driving device comprising: a driving unit that moves the holder supported by the holder in a direction in which the holder can be displaced.