JP2002367205A - Optical system driver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform recording and reproducing with high accuracy by suppressing the vibration of a driver. SOLUTION: This optical system driver has at least a holder 2 which has an optical element 1, a base 4 which is arranged with this holder 2 across supporting means 3 for supporting the holder movably in an approximately perpendicular direction and/or approximately radial direction of a recording medium, driving means 5 which forms a magnetic circuit by being combined with a yoke section 4a integrally formed at this base 4 and drives the holder 2 in the approximately perpendicular direction and/or approximately radial direction of the recording medium and a carriage 6 which is placed together with the holder 2 and the driving means 5 on the base 4 and is movable along an approximately radial direction of the recording medium. The base 4 is securely fixed to the carriage 6 and the yoke section 4a and the carriage 6 are connected by an adhesive layer 10 having elasticity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical information recording and / or reproducing apparatus such as an optical disk for supporting and driving an optical system such as an objective lens for projecting a light spot on an information recording medium. The present invention relates to a system driving device.

[0002]

2. Description of the Related Art In an optical information recording and / or reproducing apparatus, it is necessary to drive an optical element such as an objective lens in a vertical direction or a radial direction while following the deflection or inclination of an optical disk surface. Therefore, the holder holding the optical element is movably supported by a plurality of support members such as metal elastic members (wire springs).

The holder is held by a base (actuator base) together with driving means for driving the holder in a substantially vertical direction and / or a substantially radial direction of the recording medium, and is fixed to a carriage (pickup body) via a viscoelastic body. Japanese Patent Application Laid-Open No. 4-319535, which relates to an optical information reading apparatus, is referred to as a prior document relating to this point.

In recent years, this type of optical recording / reproducing apparatus has a tendency to increase the recording capacity, and accordingly, it is required to accurately irradiate an objective lens with a light beam. It is an essential condition that the optical axis of the objective lens is perpendicular to the recording medium, and the apparatus disclosed in the above publication also requires an objective lens that cannot be avoided as a reaction during servo drive. The applied vibration is reduced by the viscoelastic body, and the servo system is a high-performance device that is not affected by vibration.However, the conventional device equipped with the viscoelastic body has Large deformation (elongation / shrinkage) with temperature change compared to metal members
Therefore, when the viscoelastic body is exposed to a high-temperature, low-temperature, or high-humidity environment for a long period of time, even if the viscoelastic body is routinely placed in a normal environment, it does not restore its original state. As a result, the positional relationship between the actuator base and the pickup body fluctuates, and the optical axis of the objective lens may be displaced.

[0005]

SUMMARY OF THE INVENTION In view of the above-mentioned conventional circumstances, the present invention prevents the optical axis of the objective lens from being displaced due to a change in the installation environment such as temperature and humidity, and has a function of causing resonance. It is an object of the present invention to propose a high-performance optical system driving device capable of suppressing harmful vibration.

[0006]

According to the present invention, there is provided a base provided with a holder having an optical element and a supporting means for supporting the holder so as to be movable in a substantially vertical direction and / or a substantially radial direction of a recording medium. Drive means for forming a magnetic circuit in combination with a yoke portion integrally formed on the base to drive the holder in a direction substantially perpendicular and / or substantially radial to the recording medium; and An optical system driving device including at least a carriage mounted thereon and movable along a substantially radial direction of the recording medium,
An optical system driving device characterized in that the base is firmly fixed to a carriage, and the yoke portion and the carriage are connected by an adhesive layer having elasticity.

In the apparatus having the above-described structure, it is desirable to provide a through hole for supplying a material for forming an adhesive layer to the carriage, and a urethane-like member is arranged between the base and the carriage. It is preferable to form the adhesive layer using the urethane-like member as a guide.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below more specifically with reference to the drawings.

FIGS. 1 to 5 show a first embodiment of the device according to the present invention, and FIG. 1 is a perspective view showing the appearance of the device in a state where the device is completely assembled.
3 and 4 are external perspective views showing the disassembled state of the apparatus shown in FIG. 1, and FIG. 5 is a view showing a cross section of a main part (side cross section) of the apparatus shown in FIG.

In FIG. 1, reference numeral 1 denotes an objective lens as an optical element, 2 denotes a holder for fixing and holding the objective lens 1, 3
Is a support means for supporting the holder 2 movably in a substantially vertical direction and / or a substantially radial direction of a recording medium (not shown); 4 is a base for mounting the holder 2 together with the support means 3;
Driving means 5 for forming a magnetic circuit in combination with the yoke 4a integrally provided on the base 4 to drive the holder 2 in a substantially vertical direction and / or a substantially radial direction of a recording medium (not shown); Reference numeral 6 denotes a carriage on which the base 4 is placed together with the holder 2, the support means 3 and the drive means, and which is movable along a substantially radial direction of the recording medium.

In FIG. 2, reference numeral 7 denotes a triangular prism fixed and held on the bottom surface of the carriage 6 by bonding. The triangular prism 7 has a function of bending a light beam such as a laser beam introduced into the inside of the apparatus and causing the light beam to enter the objective lens 1.

As shown in FIG. 3, a disassembled state of each component of the apparatus is shown. As shown in FIG. Around the leaf spring 3b which covers and covers the leaf spring 3b shown in the four examples in which the other end is engaged with the holder 2 (a beryllium copper material having a thickness of about 70 μm or the like is applicable) and the fixing member 3a. The cover 3c forms a space area (not shown) for filling a silicon gel or the like for damping.

In FIG. 3, a driving means 5 includes a hollow bobbin 5a, a focus coil 5b wound on the bobbin 5a, and a tracking coil 5d and a yoke of the base 4 which are fitted and held by a convex portion 5c of the bobbin 5a. Magnet 4 fixed at the portion 4a and the rising wall 4b of the yoke portion 4a
The drive means 5 forms a magnetic circuit for moving the holder 2 in the vertical direction (Z direction) and the radial direction (X direction) of the recording medium.

The focus coil 5b is wound around the bobbin 5a, and the tracking coil 5d is connected to the projection 5c of the bobbin 5a.
In this case, the positioning can be performed more accurately and the assembling workability can be improved as compared with the case where the tracking coil is mounted with the focus coil as the air core coil.

An assembly including all of the holder 2, the supporting means 3, and the driving means 5 formed on the base 4 is referred to as a biaxial actuator A herein. As shown in the figure, a projection 8 having a curved surface (spherical surface) is integrally provided on the bottom surface of the base 4, while a spherical surface suitable for the projection 8 is provided on the bottom surface of the carriage 6. A conical concave portion 9 is provided integrally, and the biaxial actuator A is formed by the protrusion 8 and the concave portion 9.
And the carriage 6 are firmly connected via an adhesive.

The projection 8 and the concave portion 9 have surfaces that rub against each other. The biaxial actuator A can be mounted on the carriage 6 at a relatively free angle. The two-axis actuator A is fixed to the carriage 6 while using an adjusting device to adjust the position of the actuator to be perpendicular to the recording medium.

Although not shown, a triangular prism 7 is mounted on the carriage 6, but a laser, a detector for signal detection, and an optical component for signal separation are mounted on the carriage 6.

In FIG. 5 showing a cross section of the apparatus, reference numeral 10 denotes an adhesive layer having elasticity. When the adhesive interposed between the projection 8 and the concave portion 9 is hardened and the biaxial actuator A is securely fixed to the carriage 6, the yoke portion 4a and the carriage 6 are connected by the elastic adhesive layer 10. In order to fill the material, for example, Super X of Cemedine is filled.

In forming the adhesive layer 10, a material may be filled by inserting an injection needle 11 whose tip is bent from the Z + direction as shown in FIG.

The operation of the first embodiment configured as described above will be described below.

The laser beam emitted from the optical system is reflected and bent by the triangular prism 7 arranged on the carriage 6, and forms a spot on a recording medium (not shown) via the objective lens 1 located immediately above the triangular prism.

The reflected beam forms a spot on the recording medium and returns to the optical system through the lens 1 and the triangular prism 7 again to detect a focus error, a tracking error, and a recording signal.

When a focus error and a tracking error are detected, the holder 2 is driven in a predetermined direction by applying a current to the focus coil 5b and the tracking coil 5d via the leaf spring 3b. In accordance with such a procedure, the focus control and the tracking control are performed on the holder 2 and the objective lens 1 held by the holder.

In the driving device shown in the first embodiment,
The biaxial actuator A and the carriage 6 are composed of the protrusion 8 and the concave portion 9.
The two-axis actuator A does not move with respect to the carriage 6 due to the influence of the temperature change and the storage environment, and the optical axis of the lens 1 can be accurately held. , And can cope with highly accurate recording and reproduction.

The adhesive layer 10 provided between the yoke 4a and the carriage 6 suppresses the vibration of the magnetic circuit applied as a reaction to the vibration of the yoke 4a when the biaxial actuator A is driven. The vibration can be prevented from being transmitted to the carriage 6, and an optical system driving device excellent in optical characteristics and mechanically and electrically can be configured.

If a material that forms a hard adhesive layer having no elasticity after curing is used for the adhesive layer 10, the yoke portion 4a will support a portion of large vibration, and the vibration on the yoke portion 4a side will be reduced. Although suppressed, transmission of vibration to the carriage 6 is inevitable. In particular, in a small-sized and lightweight pickup, the strength of the main body tends to be low. Therefore, when such vibration is transmitted to the carriage 6, the apparatus itself vibrates, and the vibration as a whole system is large. turn into. For this reason, a material having elasticity even after curing is applied as the adhesive layer 10.

As a result of disposing the adhesive layer 10, the vibration of the yoke 4a is effectively suppressed, and the carriage 6 does not vibrate. Therefore, an optical system driving device having good resonance characteristics in which unnecessary vibration of the two-axis actuator A is suppressed can be configured.

FIGS. 6 and 7 show a second embodiment of the present invention. FIG. 6 is an external perspective view of the disassembled state of the apparatus, and FIG. 7 is a sectional view thereof.

In this embodiment, as shown in FIGS. 6 and 7, a through hole 12 is provided in the bottom surface of the carriage 6, and a material for forming the adhesive layer 10 is supplied (injected) through the through hole 12. By using such a structure, the operation using the bent injection needle 11 as shown in FIG. 5 is unnecessary, and the workability is improved.

The shape of the through hole 12 does not necessarily have to be circular, and can be changed as appropriate. About the number, a plurality can be provided. This is because it may be more effective to provide the elastic adhesive layer 10 in the widest possible range, and the provision of the plurality of through holes 12 makes the material supply operation much easier. .

FIGS. 8, 9 and 10 show a third embodiment of the present invention. FIG. 8 is an external perspective view of the device in an exploded state, and FIG. 9 is a sectional view of the device. FIG. 10 is an external perspective view showing the constituent members alone.

In the present embodiment, as shown in FIG. 8, a U-shaped urethane-like member 13 is previously attached to the back surface (Z-side portion) h of the bottom wall of the yoke portion 4a, and then the biaxial actuator A Is firmly adhered and fixed to the carriage 6, and the other configuration is almost the same as that of the first embodiment.

When the biaxial actuator A is fixed to the carriage 6, the urethane-like member 13 contracts in accordance with the concave portion 9 of the carriage 6, so that such a member does not hinder the union of the biaxial actuator A and the carriage 6. .

Also in the device having this structure, the adhesive layer 10 is formed after the biaxial actuator A is firmly fixed to the carriage 6, but in this case, the material for forming the adhesive layer 10 is The adhesive layer 10 is supplied to the U-shaped space 13a of the urethane-like member 13, and by supplying the material for this purpose, the adhesive layer 10 is always formed at a fixed position, so that the quality of the device is stabilized. Workability can be improved. Also, the urethane-like member 13
Since the device itself also exhibits a vibration suppressing effect, the performance of the optical system driving device can be further enhanced.

Although the embodiments of the present invention have been described above, the present invention is not limited to the illustrated ones, and various modifications can be made in accordance with changes in the type of the apparatus and the environment in which the apparatus is installed. is there. In particular, as a device type, one magnetic circuit may be provided, two magnetic circuits may be provided, and in the case of two devices, the present invention can be applied to only one of them.

[Brief description of the drawings]

FIG. 1 is an external perspective view showing a first embodiment of a device according to the present invention.

FIG. 2 is a perspective view showing an exploded state of the apparatus shown in FIG.

FIG. 3 is a perspective view showing an exploded state of the device shown in FIG. 1;

FIG. 4 is a perspective view showing an exploded state of the device shown in FIG.

5 is a diagram showing a cross section of a main part of the device shown in FIG. 1;

FIG. 6 is an external perspective view of a second embodiment of the present invention in an exploded state.

FIG. 7 is a view showing a cross section of a main part of the device shown in FIG. 6;

FIG. 8 is an external perspective view of a third embodiment of the present invention in an exploded state.

FIG. 9 is a diagram showing a cross section of a main part of the device shown in FIG. 8;

FIG. 10 is an external perspective view showing components of the apparatus shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Objective lens 2 Holder 3 Supporting means 3a Fixing member 3b Leaf spring 3c Cover 4 Base 4a Yoke part 5 Drive means 5a Bobbin 5b Focus coil 5c Convex part 5d Tracking coil 5e Magnet 6 Carriage 7 Triangular prism 8 Projection 9 Concave part 10 Adhesive layer 11 Injection needle 12 Through hole 13 Urethane-like member 13a U-shaped space A Biaxial actuator h Bottom wall back

Claims (3)

[Claims] 1. A holder provided with an optical element, a base disposed via support means for supporting the holder so as to be movable in a substantially vertical direction and / or a substantially radial direction of a recording medium, and integrally formed with the base. Drive means for forming a magnetic circuit in combination with the yoke portion and driving the optical element fixed to the holder in a substantially vertical direction and / or a substantially radial direction of the recording medium; and mounting the base together with the holder and the drive means. An optical system driving device comprising at least a carriage that is placed and movable along a substantially radial direction of a recording medium, wherein the base is firmly fixed to the carriage, and the yoke portion and the carriage are connected by an elastic adhesive layer. An optical system driving device, comprising: 2. The optical system driving device according to claim 1, wherein the carriage has a through hole for supplying a material for forming the adhesive layer. 3. The optical system driving device according to claim 1, wherein a urethane-like member is disposed between the base and the carriage, and an adhesive layer is formed using the urethane-like member as a guide.