JP3102280B2 - Objective lens actuator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an objective lens actuator for recording on or reproducing from an optical disk-shaped recording / reproducing medium.

[0002]

2. Description of the Related Art In recent years, a device for recording and reproducing information (hereinafter, referred to as an optical disk device) using a disk-shaped optical recording / reproducing medium (hereinafter, referred to as a disk) has advantages of large capacity and high speed. Recognized and widely used for voice, image and data recording. Among the components incorporated in the optical disk device, the objective lens actuator is positioned as an important mechanical component that affects recording / reproducing performance.

Hereinafter, a conventional objective lens actuator will be described with reference to the drawings. FIG. 7 is an external perspective view of a conventional objective lens actuator. This example shows an objective lens actuator using four suspension wires for holding a lens holder, and is widely used at present.

In FIG. 7, an objective lens 1 is adhered and fixed to an upper surface of the lens holder 32 and a balance weight (not shown) is adhered and fixed to a lower surface of the lens holder 32, and a distal end of a suspension wire 39 which is a linear spring member is fixed to both sides by soldering. The soldering board 35 for the N-S
Two magnets 3 magnetized in the directions are adhesively fixed.
A support holder 37 is fixed to one end of the base 40, and a soldering board 38 for soldering and fixing the other end of the suspension wire 39 is bonded and fixed to the support holder 37. The suspension wire 39 is obtained by cutting a linear spring material into a predetermined length, and includes a small hole 33 of a soldering board 38 made of a printed board, a small hole 34 of a support holder 37 and a small hole 35 of a lens holder 32. Through
Four are arranged in parallel, and both ends of the lens holder 32
Board 35 and support holder 37 fixed to
The soldering portion 4 in the figure is attached to the soldering board 38 fixed to
Soldered at 1 and 42.

An electromagnetic coil 36 which is opposed to and separates from the magnet 3 and electromagnetically drives the magnet 3 is also fixed at a predetermined position on the base 40, and has an axis indicated by arrows X1-X2 and an axis indicated by arrows Y1-Y2. And two types of windings.

Next, referring to FIG. 8, the support holder 37 shown in FIG.
The root structure holding the four suspension wires 39 will be described. Peripheral parts that are not relevant to the description are not shown. 8, when the support holder 37 is viewed from the lens holder 32 side, four holes 37d are provided at the root holding the suspension wire 39.
A viscoelastic body, for example, a silicon-based gel is injected into each of the dampers 7d as the damping member 37e.

The operation of the conventional objective lens actuator configured as described above will be described below.
Both ends of the suspension wire 39 are fixed, the lens holder 32 side is cantilevered with respect to the support holder 37, and the lens holder 32 is connected to the arrow X1-X2 and the arrow Y1.
It is possible to translate in the −Y2 direction.
When a current was applied to two types of windings of the electromagnetic coil 36 centering on the arrows X1-X2 and the arrow Y1-Y2, they were opposed to and separated from the windings and magnetized in the NS direction. Magnet 3
Arrow X on the magnet 3 due to the electromagnetic force generated between
1-X2, Y1-Y2 driving force is generated to move the lens holder 32 and therefore the objective lens 1 fixed thereto.
Are driven in the directions of arrows X1-X2, Y1-Y2.

As a result, it is possible to move the focal position of the laser beam condensed on the disk (not shown) above the objective lens through the objective lens 1, so that the disk can oscillate in the surface direction and eccentricity in the radial direction. Recording or reproducing operation of the information signal.

[0009]

However, in the above-described conventional configuration, the signal current applied to the two types of windings of the electromagnetic coil 36 is not affected by the electromagnetic force generated between the magnet 3 and the magnet 3 opposed to and separated from the signal current. Arrow X1-
A driving force in the X2, Y1-Y2 directions is generated to drive the lens holder 32, and thus the objective lens 1 fixed thereto.
Is driven in the directions of arrows X1-X2 and Y1-Y2. The lens holder 32 supported by the suspension wire 39 in a cantilever manner has a well-known primary resonance point. If it is large, it becomes difficult to control the driving of the objective lens actuator. As one method of suppressing this primary resonance phenomenon, control is performed using a viscoelastic damping material as shown in FIG. 8, but as can be seen from FIG. 8, four thin holes 37d are separately machined. And the suspension wire 39 with four holes 37d
It is troublesome to uniformly inject the viscoelastic body as the braking material 37e around each of the members, and there is a problem that productivity is low.

The present invention solves the above-mentioned conventional problems, and provides an objective lens actuator which is easy to process parts, requires a small number of viscoelastic material injections, is easy to assemble, and is excellent in primary resonance suppression. The purpose is to do.

[0011]

According to the present invention, there is provided an objective lens system comprising:
The tutor includes a lens holding member that holds an objective lens, a plurality of first linear spring members implanted on a first surface of the lens holding member, and a plurality of first linear spring members, respectively. And a plurality of second linear spring members implanted on a second surface of the lens holding member that faces the first surface. A plurality of second linear spring members and a contact portion separated by a small space from each other, and the other end is implanted on the opposite surface of the fixed member facing the first surface via a lens holding member. A plurality of third linear spring members, and a viscoelastic material formed to include a contact portion between the second linear spring member and the third linear spring member. In this configuration, the first and second linear spring members may be integrated.

[0012]

The objective lens actuator of the present invention has a second
And a contact portion between the linear spring member and the third linear spring member.
Elastic material by the configuration comprising the viscoelastic material formed by
This serves to facilitate formation of a damping material that suppresses primary resonance due to damping .

[0013]

Embodiments of the present invention will be described below with reference to the drawings. Figure 1 is an external perspective view of the objective lens actuator of Kazumi施例of the present invention, FIG 2 is an exploded perspective view of the objective lens actuator, FIG 4 is a fragmentary plan view of a portion of braking the linear spring member . The lens holder 2 is a lens holding member made of a synthetic resin 1 and Figure 2 the objective lens 1 on the upper surface of the figure, the optical plate 4 is bonded and fixed to the lower surface, a line to the protrusion 2a of the both side surfaces The tip of the suspension wire 8 which is a spring member is molded and fixed by molding. As shown in the figure, two magnets 3 magnetized in the NS direction are fixed to the protrusion 2a and the other two side surfaces at the positions of 90 degrees by bonding or molding. The other end of the suspension wire 8 is molded and fixed at one of four fixing points 8a to 8d on one side wall 10a of the frame-shaped housing 10 which is a fixing member formed of a synthetic resin. A hole 11 for attachment is provided as appropriate.

The coil frame 5 made of synthetic resin has a winding portion 5a at the center, a covering portion 5b having a protruding portion 5c at one end at both ends thereof, and two coating portions 5b on both outer sides thereof. There are wire winding grooves 5e and 5f, and the housing 1
Positioning fixed holes 5g for firmly fitting and fixing to the positioning fixing pins 10b protruding from the four corners 0 are provided on both lower surfaces. In the winding part 5a, an electromagnetic coil 6 has an arrow X1-X on the winding 6a around the arrow Y1-Y2.
The windings 6b around 2 are wound around one another. The beginning and end of each winding are wound around the wire processing grooves 5e and 5f several times, and the outer edges of the wound wires are fixed by soldering. For example, a flexible printed circuit board is brought into contact with this portion, and a signal current is applied to the electromagnetic coil 6 by soldering.

A damping material holding frame 7 made of a transparent synthetic resin has, at both ends, positioning fixing holes 7a for firmly fitting and fixing to positioning fixing pins 10c protruding from two places below the housing 10. Two partition walls 7 inside
have b.

The assembling method of the objective lens actuator of the present embodiment configured as described above will be described below. Suspension wires 8 a which is molded fixed to the protrusion 2a of the both sides of the lens holder 2, the lens holder
2 through the projections 2a on both sides of the second linear spring part.
Material 8b, and a suspension pen in the housing 10.
Side wall opposite to the side wall 10a holding the wire 8a
The third linear spring member 8c implanted from 10d is small
They are in contact with each other via a space contact portion 8d. In this case,
As a method of suspension, pass through from side wall 10a to side wall 10d
The pension wire 8a is stretched, and the mold is
Or not good if you make by burning off with a laser beam. Not so
Sometimes, the suspension wire 8a and the second
The third linear spring members 8b and 8c are different and have different numbers.
It may be. The two coil frames 5 on which the coils 6 are wound from above the housing 10 are press-fitted symmetrically with respect to the objective lens 1 with the positioning fixing pins 10b of the housing 10 aligned with the positioning fixed holes 5g.

The viscoelastic body 12 is provided on the contact portion 8d by some method. A viscoelastic body that has not been hardened yet may be adhered to this part and hardened, or it may be molded by a secondary molding method using a metal mold. Viscoelastic body 12
Then, a viscoelastic body such as rubber or elastomer can be applied,
The suspension wires 8a and 8b connect the lens holder 2
Optimal viscoelastic braking effect when supporting and vibrating
You may have it. Or, as the viscoelastic body 12, viscoelastic
In addition to the body, for example, UV curability mainly composed of silicon
The damping material is gelled by irradiating it with ultraviolet light.
And the suspension wires 8a and 8b are
For optimal braking effect when vibrating while supporting 2
Is also good.

Next, the operation of the objective lens actuator of this embodiment thus constructed will be described. The operation of the electromagnetic coil 6 with the arrow X1-X2 as the axis and the arrow Y1-
When an electric current is applied to each of the windings 6a and 6b around Y2 and the two types of windings 6a and 6b, the lens holder 2 is caused by an electromagnetic force generated between the magnets 3 which are opposed to and separated from each other and magnetized in the NS direction. Arrows X1-X2, Y
And 1-Y2 direction of the driving force is generated drive, the suspension wire 8 a, the shown lifting lenses holder 2 by 8b and 8c, thus the objective lens 1 fixed thereto in the arrow X1-X2, Y1-Y2 direction I do. At this time, viscoelastic
Sex body 12 acts to reduce the amplitude of the peaks of the primary resonant give optimum braking effect for the suspension wires 8 a and 8b to vibrate supporting the lens holder 2.

This makes it possible to move the focal position of the laser beam focused on the disk (not shown) located above the drawing through the objective lens 1 with respect to the objective lens, and the surface deflection and radius in the surface direction of the disk The recording and reproducing operation of the information signal is performed following the eccentricity of the direction.

The suspension wire according to the present invention is
The fixing portion between the housing 8a and the side wall 10a of the housing 10 is
It may be implanted directly on the jing 10, but the fixed part also has a braking material
May be provided.

As an example, as shown in FIG. 3, the damping material holding frame 7 and its partition wall 7b are fixed at a fixed position by the inner wall 10d of the housing 10, the inner wall of the side wall 10a, and the covering portion 5b of the coil frame 5. since the 5-way a configuration for making the space surrounding the suspension wires 8 a two by two, the space of the liquid in, for example, silicon a damping material having an ultraviolet curable mainly is a braking member 9 by injecting transparent Gel is formed by irradiating ultraviolet rays from the lower surface of the braking material holding frame 7 so that the suspension wire 8 has an optimal braking effect when the suspension wire 8 vibrates while supporting the lens holder 2.

Alternatively , fix the suspension wire
A configuration in which a fixing member is provided may be used. FIG. 5 is a perspective view of a main part of the braking unit, which is obtained by improving only the braking unit based on FIG. 7 of the conventional example. An integral concave portion 27b is provided around the suspension wire 29 of the fixing member 27a, and a braking member 27c that collectively brakes at least one pair (two pairs in the figure) of linear spring members is provided in the concave portion 27b. Injected. This saves the time and labor of injecting into the narrow holes as in the conventional example as shown in FIG. 8, and the wide recess 27b facilitates the injecting, thereby increasing the productivity.

For fixing the housing 10 and the damping material holding frame 7 to each other, besides the exemplified method, the respective positioning fixing pins and positioning fixing holes may be exchanged. After the members are provided, they may be fixed by bonding or ultrasonic welding.

It is preferable to partially enlarge the cross-sectional area of a part of the linear spring member to be sealed in the viscoelastic material in the following point. That is, FIG. 6 is a diagram showing a processing form of the linear spring of the main part. This embodiment may be implemented in addition to the conventional example shown in FIGS . 3, 5, and 8. FIG. 6 (a) shows an example applied to the conventional example shown in FIG. 8, in which an enlarged cross-sectional portion 29a is provided in a portion of the suspension wire 29 which is enclosed in the braking material 27e to increase the resistance to the braking material 27e. It is. FIG. 6 (b) shows a state where solder or the like is attached,
FIG. 6 (c) shows a projection provided with a press or the like, FIG. 6 (d)
Is a part of which has a flat part formed by a press or the like. As a result, the intended primary resonance can be effectively suppressed. In the case of FIG. 6A, the workability is not improved, but when applied to FIGS. 3 and 5, a better effect can be expected due to the improvement of the workability.

Each of the linear spring members at the fixed portion
Each of the embodiments is independently of the present invention described with reference to FIG.
It may be implemented in combination with the form,
It may be implemented by combining the aspects . Needless to say, the present invention may be implemented by adding a conventionally known example.

[0026]

As described above, according to the objective lens actuator of the present invention, the viscoelastic material is formed including the contact portion between the second linear spring member and the third linear spring member. the configuration with the door, the primary by the braking resilient material
In addition to the resonance suppression effect, a damping material for performing the damping can be easily formed, so that cost can be reduced and manufacturing efficiency can be increased. In addition, when the linear spring member has a configuration in which an enlarged cross section is partially provided in a portion sealed in the viscoelastic material, a braking effect against primary resonance can be further enhanced by the enlarged cross section.

[Brief description of the drawings]

FIG. 1 is an external perspective view of an objective lens actuator according to one embodiment of the present invention.

FIG. 2 is an exploded perspective view of the objective lens actuator.

FIG. 3 is a perspective view of a main part of a braking unit according to an embodiment of the present invention .

FIG. 4 is a plan view of a main part of a braking unit according to an embodiment of the present invention .

FIG. 5 is a perspective view of a main part of a braking unit according to an embodiment of the present invention .

6A is a sectional view of a main part of a braking unit according to an embodiment of the present invention . FIGS. 6B to 6D are processed views of a linear spring member according to an embodiment of the present invention .

FIG. 7 is an external perspective view of a conventional objective lens actuator.

FIG. 8 is a perspective view of a main part of a braking unit of the objective lens actuator.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Objective lens 2 Lens holder (lens holding member) 5 Coil frame 7 Brake material holding frame 7b Partition 8, 29 Suspension wire (linear spring member) 8a First linear spring member 8b Second linear spring member 8c 3 linear spring member 8d contact portion 9, 27c, 27e braking member 10 housing (fixing member) 12 viscoelastic member 27a fixing member

Continuation of the front page (56) References JP-A-2-232824 (JP, A) JP-A-5-189783 (JP, A) JP-A-5-114151 (JP, A) Jpn. , U) Hikaru 4-121027 (JP, U) (58) Fields studied (Int. Cl. ⁷ , DB name) G11B ^7/ 09-7/095

Claims (2)

(57) [Claims] 1. A lens holding member for holding an objective lens, and a plurality of first lenses implanted on a first surface of the lens holding member.
A frame-shaped fixing member that cantileverly fixes each of the plurality of first linear spring members on the first surface; and a frame facing the first surface of the lens holding member. A plurality of second linear spring members implanted on a certain second surface; and a contact portion separated from the plurality of second linear spring members by a small space, and the other end is fixed. The first of the member
And a plurality of third linear spring members implanted on the opposite surface of the first linear spring member and the second linear spring member between the second linear spring member and the third linear spring member. An objective lens actuator comprising: a viscoelastic material formed to include the contact portion. 2. A first objective lens actuator according to claim 1, wherein the second linear spring members are integral.