JPH08203097A - Objective lens actuator - Google Patents

Abstract

(57) [Summary] [Objective] Unnecessary resonance above a secondary mode such as torsional resonance of a support member, which is a component of an objective lens actuator used in an optical recording / reproducing apparatus, is suppressed. [Structure] Four or more linear supporting members 5a, one end of which is fixed in a direction perpendicular to the optical axis direction of the objective lens 8 and the other end of which is fixed to a base 6 provided on the objective lens holder 7. 5b,
By covering the central control plate of 5c, 5d with the vibration absorbing material 12a, 12b, 12c, 12d made of gel-like silicone rubber, the variation in the assembling of the supporting members 5a, 5b, 5c, 5d can be prevented. As a result, it is possible to suppress unnecessary resonance above the secondary mode such as torsional resonance of the linear support member due to the collapse of the driving balance when driving the objective lens holder, and it is possible to improve the stability of servo performance.

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 used in an optical recording / reproducing apparatus for recording / reproducing information by condensing a light beam emitted from a light source such as a semiconductor laser on an information recording medium. It is a thing.

[0002]

2. Description of the Related Art A conventional objective lens actuator of this type is constructed as shown in the perspective view of FIG. That is, the base 1 made of a magnetic metal plate fixed between the light source section (not shown) and the information recording medium (not shown) of the optical recording / reproducing apparatus is projected in a rectangular parallelepiped shape at both ends of the base 1. Magnet holding pieces 3a, 3b for holding the rectangular magnets 2a, 2b are provided so as to face each other. Inside the respective magnet holding pieces 3a, 3b, rectangular magnetic path pieces 4a, 4b are fixed. It is provided with a space. On the outer side of the magnet holding piece 3b, a base 6 to which one ends of four linear supporting members 5a, 5b, 5c and 5d parallel to each other are fixed is attached, and the supporting members 5a, 5
A substantially rectangular objective lens holder 7 made of a material such as polyphenylene sulfide resin, epoxy resin, liquid crystal polymer resin or the like is fixed to the other ends of b, 5c and 5d. An objective lens 8 is incorporated in the center of the objective lens holder 7. On the other hand, a focusing control coil 9 is wound around the objective lens holder 7, and four ring-shaped tracking control coils connected to the opposite end faces around the objective lens 8 on the outer periphery thereof. 10 are coupled, and both coils 9 and 10 are arranged in the space between the magnets 2a and 2b and the magnetic path pieces 4a and 4b.

With such a structure, the focus deviation of the light beam with respect to the surface of the information recording medium and the track groove deviation of the light beam with respect to the track groove of the information recording medium surface are detected, and the detection control signal detects the focusing control coil 9 and the tracking. Apply a current to the control coil 10 to move the magnet 2
The objective lens 8 is moved up and down in the focusing direction F, which is the same direction as the optical axis of the objective lens, by using the magnetic flux in which a magnetic field is always formed by the a and 2b, the magnet holding pieces 3a and 3b, and the magnetic path pieces 4a and 4b. At the same time, the position of the objective lens 8 is controlled by driving the objective lens 8 in parallel with the tracking direction T which is a direction perpendicular to the optical axis direction of the objective lens.

[0004]

However, in the above structure, the objective lens holder 7 is driven in the focusing direction F and the tracking direction T due to variations in the lengths of the supporting members 5a to 5d and the mounting intervals during assembly. In the case where the objective lens actuator is moved in the tracking direction T, the support members 5a to 5d are liable to cause unnecessary resonances such as torsional resonances in a secondary mode or higher.
As a result, there is a problem in that the stability of the servo performance, which is the performance of causing the light beam spot condensed by the objective lens to follow the surface wobbling and eccentricity of the information recording medium, is poor.

It is an object of the present invention to suppress unnecessary resonance of a secondary mode or higher, such as torsional resonance of the support member, and to improve stability of servo performance.

[0006]

In order to achieve the above object, the present invention provides a first means for holding an objective lens holding body for holding an objective lens, and the objective lens holding body parallel to an optical axis of an optical system. With a control coil for driving in different directions and a control coil for driving in a vertical direction and a magnetic circuit or magnet,
It has four or more linear support members, one end of which is fixed in a direction perpendicular to the optical axis direction of the objective lens and the other end of which is fixed to the objective lens holding body, and which is cut in the central portion of the support member. It is characterized in that it has a control plate having a large area, and that this control plate is covered with a vibration absorbing material such as gel silicone rubber.

Further, the second means drives the objective lens holder for holding the objective lens, the control coil for driving the objective lens holder in a direction parallel to the optical axis of the optical system, and the vertical direction. It has a control coil and a magnetic circuit or a magnet, one end of which is fixed in a direction perpendicular to the optical axis direction of the objective lens, and the other end of which is provided with an adhesive layer of an acrylate resin on a base provided on the objective lens holder. It is characterized in that it has four or more linear support members adhered via.

The third means includes an objective lens holder for holding the objective lens, a control coil for driving the objective lens holder in a direction parallel to the optical axis of the optical system, and a vertical drive. It has a control coil and a magnetic circuit or a magnet, and one end is fixed in a direction perpendicular to the optical axis direction of the objective lens, and the other end holds the objective lens holding body via a vibration absorbing material of gel silicone rubber. It is characterized by having four or more linear support members.

[0009]

According to the present invention, when the objective lens holder is driven in the focusing direction and the tracking direction, the first means covers the central control plate of the supporting member with a vibration absorbing material such as gel silicone rubber. In the second means, the other end of the supporting member is adhered to the base provided on the objective lens holder via an adhesive layer of acrylate resin. By holding the objective lens holder through the vibration absorbing material of gel-like silicone rubber at the end, the influence of variations during assembly,
It is possible to suppress unnecessary resonance above the secondary mode, such as torsional resonance of the linear support member due to the loss of drive balance when the objective lens holder is driven.

As a result, it is possible to enhance the stability of the servo performance which shows the performance of causing the light beam spot focused by the objective lens to follow the surface wobbling and eccentricity of the information recording medium.

[0011]

【Example】

(Embodiment 1) FIG. 1 is a perspective view showing the structure of an objective lens actuator according to a first embodiment of the present invention. In FIG. 1, the same components as those of FIG. 7 of the conventional example are designated by the same reference numerals, and the description thereof will be omitted. Here, 11a and 11b are substantially rectangular parallelepiped vibration absorbing material holding pieces attached to the base 1,
12a, 12b, 12c, 12d (12d is not shown in the perspective view of FIG. 1, but it is located below 12c) are the vibration absorbing material holding pieces.
It is a vibration absorber made of gel-like silicone rubber held by 11a and 11b.

FIG. 2 is a plan view (1) showing the structure of the supporting member of FIG. 1 and a side view (2) thereof, showing each supporting member 5a (5).
A circular control plate 13a (13b, 13c, 13d also has a similar structure and is omitted) is provided at the center of b, 5c and 5d which has a similar structure and is omitted.

The control plates 13a, 13b, 13c, 13d penetrate through the vibration absorbing materials 12a, 12b, 12c, 12d held by the vibration absorbing material holding pieces 11a, 11b attached to the base 1. There is.

Next, the movable body composed of the objective lens holder 7, the objective lens 8, the focusing control coil 9 and the tracking control coil 10 is in the tracking direction which is the direction perpendicular to the optical axis direction of the objective lens 8. Even when T and the focusing direction F, which is the same direction as the optical axis direction of the objective lens 8, are moved simultaneously, the supporting members 5a, 5b, 5c, 5d
Control plates 13a, 13b, 13 at the center where the vibration amplitude of
Vibration absorber 12 made of gel-like silicone rubber for c and 13d 12
Since it is covered with a, 12b, 12c, 12d, the support member 5
It is possible to suppress unnecessary resonance in the secondary modes of a, 5b, 5c, and 5d or higher, thereby making it difficult to transmit the unnecessary resonance to the objective lens 8. As a result, it is possible to suppress unnecessary resonance due to the influence of variations in the length of the support member, the mounting interval, and the like during assembly.

Further, circular control plates 13a, 13b, 13c, 13d are provided at the central portions of the supporting members 5a, 5b, 5c, 5d, and vibration absorbing materials 12a, 12b, 12c, made of gel silicone rubber or the like. 1
Since it is covered with 2d, the supporting members 5a, 5b, 5c, 5d
The mechanical resistance in the axial direction becomes, and the unnecessary resonance component in the axial direction of the support member can be further suppressed.

As a result, it is possible to enhance the stability of the servo performance which shows the performance of causing the light beam spot condensed by the objective lens 8 to follow the surface wobbling and eccentricity of the information recording medium.

(Embodiment 2) FIG. 3 is a perspective view showing the structure of an objective lens actuator according to a second embodiment of the present invention.
FIG. 4 is a partial sectional view taken along the line AA of FIG.

3 and 4, the same components as those in FIGS. 1 and 7 are designated by the same reference numerals, and the description thereof will be omitted.
Here, 14a and 14b are yokes made of a substantially rectangular parallelepiped magnetic metal at both ends of the base 1, and these are focusing control coils 9a and 9 so that their winding axis directions are orthogonal to each other.
b, the tracking control coils 10a and 10b are wound.
On the outside of the yoke 14b, around which the focusing control coil 9b and the tracking control coil 10b are wound, four parallel linear support members 5a, 5b, 5 are provided.
C, 5d (5d is not shown in the perspective view of FIG. 3) is attached to a base 6 to which one end is fixed, and the supporting member 5
As shown in the partial cross-sectional view of FIG. 4, polyphenylene sulfide is attached to the other ends of a, 5b, 5c and 5d via acrylate resin adhesive layers 15a and 15b (15b is not shown in the partial cross-sectional view of FIG. 4). A substantially rectangular objective lens holder 7 made of resin, epoxy resin, liquid crystal polymer resin or the like is fixed. An objective lens 8 is incorporated in the center of the objective lens holder 7. On the other hand, magnets 2a and 2b are attached to the side surface of the objective lens holder 7 at positions facing each other with the objective lens 8 as the center.

Next, the movable body composed of the objective lens holder 7, the objective lens 8, the magnets 2a and 2b, and the acrylate resin adhesive layers 15a and 15b is perpendicular to the optical axis direction of the objective lens 8. Tracking direction T, which is the direction
Also, even if the supporting members 5a, 5a are moved simultaneously in the focusing direction F which is the same as the optical axis direction of the objective lens 8,
Since the acrylate resin adhesive layers 15a and 15b absorb vibrations due to unnecessary resonance of the secondary modes of 5b, 5c and 5d or higher, it is possible to make it difficult to transmit the unnecessary resonance to the objective lens 8. As a result, it is possible to suppress unnecessary resonance due to the influence of variations in the length of the supporting member, the mounting interval, etc. during assembly.

As a result, it is possible to enhance the stability of the servo performance which shows the performance of causing the light beam spot focused by the objective lens 8 to follow the surface wobbling and eccentricity of the information recording medium.

(Embodiment 3) FIG. 5 is a perspective view showing the structure of an objective lens actuator according to a third embodiment of the present invention.
FIG. 6 is a partial cross-sectional view (1) of a surface perpendicular to the tracking direction T of the vibration absorber holding portion of FIG. 5 and a partial cross-sectional view (2) of a surface perpendicular to the focusing direction F.

The basic structure of FIG. 5 is substantially the same as that of FIG. 3 except that it has vibration absorbing material holders 16a and 16b formed integrally with the objective lens holder 7. 5 and 6, the same components as those in FIGS. 1, 3 and 7 are designated by the same reference numerals, and the description thereof will be omitted.

In this embodiment, as shown in FIG. 5, yokes 14a and 14b made of a magnetic metal having a substantially rectangular parallelepiped shape are provided at both ends of the base 1.
Focusing control coils 9a and 9b and tracking control coils 10a and 1 so that the winding axes are orthogonal to each other.
0b is wound. The focusing control coil 9
b, on the outside of the yoke 14b around which the tracking control coil 10b is wound, a base 6 to which one end of four parallel linear support members 5a, 5b, 5c, 5d is fixed is attached. At the other ends of the support members 5a, 5b, 5c, 5d, as shown in the partial sectional views of FIGS. 6 (1) and 6 (2), a spherical movable body holding portion 17a (other 17b, 17c, 17d (Same) is provided,
Vibration absorbing material made of gel silicone rubber around it 18
It is filled with a (same for other 18b, 18c, 18d), and is a square shape using a material such as polyphenylene sulfide resin, epoxy resin, liquid crystal polymer resin, etc. through the vibration absorbing material holding portion 16a (16b has the same structure). The objective lens holder 7 is held.
The objective lens 8 is provided at the center of the objective lens holder 7.
Is built in. On the other hand, magnets 2a and 2b are attached to the side surface of the objective lens holder 7 at positions facing each other with the objective lens 8 as the center.

Next, the objective lens holder 7, the objective lens 8, the magnets 2a and 2b, and the vibration absorbing material holder.
Even if the movable body composed of 16a and 16b is simultaneously movable in a tracking direction T which is a direction perpendicular to the optical axis direction of the objective lens 8 and a focusing direction F which is the same direction as the optical axis direction of the objective lens 8. , The support members 5a, 5b, 5c,
Since the vibration absorbers 18a, 18b, 18c, and 18d absorb the vibrations due to the unnecessary resonance of the secondary mode of 5d or higher, it is possible to make it difficult to transmit the unnecessary resonance to the objective lens 8. As a result, it is possible to suppress unnecessary resonance due to the influence of variations in the length of the supporting member, the mounting interval, etc. during assembly.

As a result, it is possible to enhance the stability of the servo performance which shows the performance of causing the light beam spot condensed by the objective lens to follow the surface wobbling and eccentricity of the information recording medium.

[0026]

As described above, in the objective lens actuator of the present invention, when the objective lens holder is driven in the focusing direction and the tracking direction, the control plate having a large cross-sectional area is provided in the central portion of the supporting member, In addition, the control plate is covered with a vibration absorbing material such as gel silicone rubber, and the other end of the supporting member is adhered to a base provided on the objective lens holder through an adhesive layer of acrylate resin. Also, since the other end of the supporting member holds the objective lens holder through the vibration absorbing material of gel-like silicone rubber, the influence of variations in assembly and the line caused by the loss of drive balance when the objective lens holder is driven It is possible to suppress unnecessary resonance of a secondary mode or higher, such as torsional resonance of the support member having a rectangular shape.

As a result, it is possible to enhance the stability of the servo performance showing the performance of causing the light beam spot condensed by the objective lens to follow the surface wobbling and eccentricity of the information recording medium.

[Brief description of drawings]

FIG. 1 is a perspective view showing the structure of an objective lens actuator according to a first embodiment of the present invention.

2A and 2B are a plan view (1) and a side view (2) showing the structure of the support member of FIG.

FIG. 3 is a perspective view showing a structure of an objective lens actuator according to a second embodiment of the present invention.

4 is a partial cross-sectional view taken along the line AA of FIG.

FIG. 5 is a perspective view showing the structure of an objective lens actuator according to a third embodiment of the present invention.

FIG. 6 is a partial cross-sectional view of the vibration absorbing material holding portion of FIG.

FIG. 7 is a partial perspective view showing the structure of a conventional objective lens actuator.

[Explanation of symbols]

1 ... Base, 2a, 2b ... Magnet, 3a, 3b ... Magnet holding piece, 4a, 4b ... Magnetic path piece, 5a, 5b, 5
c, 5d ... Support member, 6 ... Base, 7 ... Objective lens holder, 8 ... Objective lens, 9 ... Focusing control coil, 10 ... Tracking control coil, 11a, 11b ...
Vibration absorber holding piece, 12a, 12b, 12c, 12d, 18a, 18b,
18c, 18d ... Vibration absorbing material, 13a, 13b, 13c, 13d ... Control plate, 14a, 14b ... Yoke, 15a, 15b ... Acrylate resin adhesive layer, 16a, 16b ... Vibration absorbing material holding portion, 17a, 17
b, 17c, 17d ... Movable body holding part.

Claims (3)

[Claims] 1. An objective lens holder for holding an objective lens, a control coil for driving the objective lens holder in a direction parallel to an optical axis of an optical system, and a control coil and a magnetic circuit for driving the objective lens holder in a vertical direction. Alternatively, the support may include four or more linear support members that have magnets and have one end fixed in a direction perpendicular to the optical axis direction of the objective lens and the other end fixed to the objective lens holder. An objective lens actuator characterized in that a control plate having a large cross-sectional area is provided in a central portion of the member, and the control plate is covered with a vibration absorbing material such as gel silicone rubber. 2. An objective lens holder for holding an objective lens, a control coil for driving the objective lens holder in a direction parallel to an optical axis of an optical system, and a control coil and a magnetic circuit for driving the objective lens holder in a vertical direction. Or a magnet, one end of which is fixed in a direction perpendicular to the optical axis direction of the objective lens, and the other end of which is adhered to a base provided on the objective lens holder through an adhesive layer of acrylate resin. An objective lens actuator having a linear support member of at least two. 3. An objective lens holder for holding an objective lens, a control coil for driving the objective lens holder in a direction parallel to an optical axis of an optical system, and a control coil and a magnetic circuit for driving the objective lens holder in a vertical direction. Alternatively, four or more linear wires having a magnet, one end of which is fixed in a direction perpendicular to the optical axis direction of the objective lens and the other end of which holds the objective lens holder through a vibration absorbing material of gel silicone rubber. An objective lens actuator, comprising: