JPH05342606A - Objective lens drive - Google Patents

Abstract

(57) [Summary] [Object] An object of the present invention is to provide an objective lens driving device having an elastic member that can be easily positioned and fixed to a lens holder or a fixing member and can be easily handled. [Structure] Elastic members 6a, 6b or elastic members 6c,
By using the square-shaped leaf springs 7 having two opposite sides of 6d, the protrusions 21 are provided on the lens holder 2 and the fixing member 10, and the leaf springs 7 are provided with holes that can be fitted to each other. Since it is not necessary to position the members 6a to 6d independently and it is not necessary to directly handle the elastic members 6a to 6d during assembly, it is possible to realize an objective lens driving device that is easy to handle.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an objective lens driving device of an optical disk device for optically writing or reading information on a disk-shaped recording medium.

[0002]

2. Description of the Related Art In an optical disk apparatus, in order to correct a focus deviation due to vertical movement of a warp of a disk-shaped recording medium such as a compact disk or an optical disk and a tracking deviation due to eccentricity, an objective lens is arranged in a direction perpendicular to a surface of the recording medium. Of the optical axis (hereinafter referred to as the focus direction F) and a radial direction parallel to the recording medium surface (hereinafter referred to as the tracking direction T) to perform optical recording or reproduction.

In recent years, portable and personalized data file devices using compact disc players and optical discs are becoming more and more popular, and optical pickups used therefor are required to be even smaller and more inexpensive. .

An example of the above-mentioned conventional objective lens driving device for an optical pickup will be described below with reference to the drawings.

FIG. 12 is an exploded perspective view showing the structure of a conventional objective lens driving device. In FIG. 12, 1 is an objective lens. A lens holder 2 holds the objective lens 1. Reference numeral 4 denotes a focus coil wound around the lens holder 2 and 5a to 5d denote tracking coils for the lens holder 2.
It is fixed to. 6a to 6d are elastic members, which are arranged so as to be substantially parallel to each other. One end is attached to the lens holder 2 via the printed circuit boards 9a and 9b, and the other end is attached to the fixing member 10 to form the lens holder. Support 2. Magnetic yokes 3a and 3b are integrated with the base 11 and form a magnetic circuit with the magnets 8a and 8b.

The operation of the objective lens driving device configured as described above will be described below.

The operation of driving the objective lens in two axes of the focus direction F and the tracking direction T in order to correct the focus shift due to the vertical movement of the warp of the disk and the tracking shift due to eccentricity will be described.

Driving in the focus direction F is performed by the objective lens 1
The lens holder 2 to which is attached the elastic member by the electrokinetic converter in which the focus coil 4 wound around the lens holder 2 is arranged in the gap of the magnetic circuit composed of the magnets 8a and 8b and the magnetic yokes 3a and 3b. Obtained by translating through 6a-6d.

For driving in the tracking direction T, the lens holder 2 to which the objective lens 1 is attached, the tracking coils 5a to 5d attached to the lens holder 2 to the magnet 8
a, 8b and the magnetic yokes 3a, 3b, the elastic members 6a ...
Obtained by translating through 6d. In addition, the entire objective lens driving device is access-driven by a motor in the access direction on the recording medium (the same direction as the tracking direction T).

[0010]

In the objective lens driving device having the above-described structure, metal wires such as phosphor bronze are used as the elastic members 6a to 6d, and the printed wiring boards 9a and 9b and the fixing member 10 are provided with end portions. In the case of a so-called MC (Moving Coil) type drive in which the driving means in the focus direction F and the tracking direction T are configured to attach the focus coil 4 and the tracking coils 5a to 5d to the lens holder, Uses soldering the end portions of the focus coil 4 and the tracking coils 5a to 5d to the metal wires 6a to 6d via the printed circuit boards 9a and 9b, and using the metal wires 6a to 6d as lead wires.

Therefore, when the metal wires 6a to 6d are attached to the lens holder 2 and the fixing member 10, the metal wires 6 are
It must be positioned so that a to 6d are substantially parallel to each other. The wire diameter of the metal wires 6a to 6d is 100 to 1
It has a problem that it is difficult to handle at the time of assembly because it is about 50 microns and is very thin.

In view of the above-mentioned problems, the present invention provides an objective lens driving device having an elastic member which has effects equivalent to those of a metal wire and which can be easily positioned, fixed and handled.

[0013]

In order to solve the above-mentioned problems, an objective lens driving device of the present invention uses two opposing sides of a square-shaped leaf spring as elastic members, and as an elastic member of the square-shaped leaf spring. In order to position and fix one of the two unused sides to the lens holder and the other to the fixing member, an uneven portion or a slit is provided on the lens holder or the fixing member, and a hole or a hole that can be fitted to the uneven portion or the slit is formed on the leaf spring. It is notched or bent.

[0014]

According to the present invention, since the elastic member portion can be formed by etching or the like by the above-described structure, the positional relationship between the respective members can be defined in advance, and at the same time, the positioning and fixing with the lens holder and the fixing member can be facilitated. An objective lens driving device having various elastic members can be realized.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An objective lens driving device according to a first embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is an exploded perspective view showing the structure of an objective lens driving device according to the first embodiment of the present invention. In FIG. 1, reference numeral 1 is an objective lens. A lens holder 2 holds the objective lens 1. A focus coil 4 is wound around the lens holder 2 and forms a magnetic circuit with 8a and 8b.

The operation of the objective lens driving device configured as described above will be described below.

The operation of driving the objective lens in two axes of the focus direction F and the tracking direction T in order to correct the focus shift due to the vertical movement of the warp of the disk and the tracking shift due to eccentricity will be described.

Driving in the focus direction F is performed by the objective lens 1.
The lens holder 2 to which is attached the elastic member by the electrokinetic converter in which the focus coil 4 wound around the lens holder 2 is arranged in the gap of the magnetic circuit composed of the magnets 8a and 8b and the magnetic yokes 3a and 3b. Obtained by translating through 6a-6d.

For driving in the tracking direction T, the lens holder 2 to which the objective lens 1 is attached, the tracking coils 5a to 5d attached to the lens holder 2 to the magnet 8
a, 8b and the magnetic yokes 3a, 3b, the elastic members 6a ...
Obtained by translating through 6d. In addition, the entire objective lens driving device is access-driven by a motor in the access direction on the recording medium (the same direction as the tracking direction T).

The lens holder 2 and the fixing member 10 are provided with protrusions 21, which are positioned and fixed by fitting with notches or edge portions of the leaf spring 7.

Further, since it is not necessary to directly handle the elastic members 6a to 6d at the time of assembly, it is possible to realize an objective lens driving device having an elastic member which can be easily handled.

Further, in the state of the leaf spring 7, the elastic members 6a ...
If a viscoelastic material (not shown) such as butyl rubber or silicon rubber is molded on 6d, a damping method excellent in mass productivity can be realized.

FIG. 2 is an exploded perspective view showing the structure of the objective lens driving device of the second embodiment of the present invention. The basic configuration is the same as that of the first embodiment shown in FIG. 1, but the leaf spring 7 is arranged perpendicularly to the focus direction F in the first embodiment, but in the second embodiment The spring 7 is arranged so as to be perpendicular to the tracking direction T. As shown in FIGS. 2 and 3, a projection 21 is provided on the lens holder 2 and the fixing member 10, and is positioned and fixed by fitting with the hole of the leaf spring 7.

Therefore, the same effect as that of the first embodiment can be obtained. Also, in the first and second embodiments,
If the thickness of the leaf spring 7 and the in-plane width of the elastic members 6a to 6d are the same, the spring constants in the focus direction F and the tracking direction T can be made the same. Of course, if the thickness of the leaf spring 7 and the in-plane width of the elastic members 6a to 6d are arbitrarily set, the spring constants in the focus direction F and the tracking direction T can be relatively freely designed.

Regarding the method of positioning and fixing, as shown in FIGS. 3, 4 and 5, for example, a projection 21 is provided on the lens holder 2, and a hole or a notch or a bend which can be fitted into the leaf spring is formed. If the elastic member (6c, 6d in FIGS. 3, 4, and 5) itself is not required to be positioned, the leaf spring 7 can be processed without using an expensive jig.
It is possible to position and fix.

Further, since it is not necessary to directly handle the elastic members 6a to 6d at the time of assembly, an objective lens driving device having an elastic member which can be easily handled can be realized.

Further, the elastic members 6a ...
If a viscoelastic material (not shown) such as butyl rubber or silicon rubber is molded on 6d, a damping method excellent in mass productivity can be realized.

FIG. 6 and FIG. 7 are perspective views of the essential parts showing the structure of the third embodiment of the present invention. Although the basic structure is the same as that of the second embodiment shown in FIG. 2, the leaf spring 7 is used because the elastic member is used as a lead wire in MC (Moving Coil) type drive as described in the conventional example. Made of a solderable material such as phosphor bronze or beryllium copper, and made of elastic members 6c, 6
By providing a fine portion 24 that can be cut after being fixed to the lens holder 2 in a portion other than d, the respective end portions of the focus coil 4 and the tracking coil (only 5b and 5c are shown in FIGS. 6 and 7) are set to a leaf spring. 7 is fixed to each of the mounting portions of the lens holder 2 by soldering, and then the fine portion 24 (obviously, the fixing member 10 side also needs to have the same configuration) is cut to fix and fix the elastic member. At the same time that the effect of facilitating is obtained, the elastic member can be used also as the lead wire. Although the MC type drive is described here, the magnet 8 is attached to the lens holder 2.
Also in the MM (Moving Magnet) type drive in which a and 8b are attached, it is not necessary to use the elastic member as the lead wire, but it is needless to say that the same effect as the MC type is obtained according to the present invention.

FIGS. 8 and 9 are perspective views showing the structure of a fourth embodiment of the present invention. The basic structure is the same as that of the second embodiment shown in FIG. When the entire objective lens driving device is driven by the motor in the access direction on the recording medium (the same direction as the tracking direction T), it is general to perform the driving without the tracking servo.

Therefore, when a force from the motor is applied to the movable portion composed of the objective lens 1, the lens holder 2, etc., residual vibration occurs in the tracking direction, and in order to perform the tracking servo again after the access is completed, the residual vibration is generated. It is necessary to wait until the vibration becomes small to some extent, which is a problem in reducing the access time. Position detection by an optical position sensor is one of means for solving this problem. The amount of displacement of the movable portion is detected by an optical position sensor and is fed back at the time of access to reduce residual vibration and shorten access time. As shown in FIG. 9, as the optical position sensor 20, a so-called reflection type optical position sensor in which a light source such as an LED and a photodetector are integrated to detect the amount of light reflected from a movable part to perform position detection. In this case, if the leaf spring 7 is used as the reflecting surface of the movable portion, it is possible to perform stable position detection without lowering the reflectance or causing variations. In addition, as shown in FIG.
In the case of a so-called transmission type optical position sensor 20 in which a light source such as an ED and a two-divided photodetector are arranged so as to face each other, if a part (bent portion 23) of the leaf spring 7 is also used as a shielding plate. Since the number of parts can be reduced and the distance between the light source and the photodetector can be reduced, the detection sensitivity can be improved.

10 and 11 are perspective views of the essential parts showing the structure of the fifth embodiment of the present invention. As the protrusion 21,
For example, when the positioning member 25 made of a conductive material such as brass is used, the leaf spring 7 is positioned and fixed, and then the ends of the focus coil 4 and the tracking coils 5a to 5d are soldered and fixed to the positioning member 25. For example, the same effect as that of the third embodiment can be obtained, and at the same time, for example, if an L-shaped positioning member is attached to the fixing member 10, the connection with the printed board 9c on the fixing portion side becomes easy.

[0033]

The two opposite sides of the square-shaped leaf spring are used as elastic members, and one of the two sides of the square-shaped leaf spring that is not used as an elastic member is positioned and fixed to the lens holder and the other side to the fixing member. The lens holder or the fixing member is provided with a concavo-convex portion or a slit, and the leaf spring is subjected to a process such as a hole or a notch that can be fitted in the concavo-convex portion or the slit, or a process such as bending to etch the elastic member portion. Since the molding can be performed by, the positional relationship of each can be defined in advance, and at the same time, an objective lens driving device having an elastic member that can be easily positioned and fixed to the lens holder and the fixing member and can be handled can be realized.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of an objective lens driving device according to a first embodiment of the present invention.

FIG. 2 is an exploded perspective view of an objective lens driving device according to the second embodiment.

FIG. 3 is a perspective view of an essential part of an objective lens driving device in the example.

FIG. 4 is a perspective view of a main part of an objective lens driving device in the example.

FIG. 5 is a perspective view of a main part of an objective lens driving device in the example.

FIG. 6 is a perspective view of a main part showing a configuration of an objective lens driving device according to the third embodiment.

FIG. 7 is a perspective view of a main part showing a configuration of an objective lens driving device in the third embodiment.

FIG. 8 is a perspective view of a principal part showing a configuration of an objective lens driving device according to the fourth embodiment.

FIG. 9 is a perspective view of a principal part showing a configuration of an objective lens driving device according to the fourth embodiment.

FIG. 10 is a perspective view of essential parts showing a configuration of an objective lens driving device in the fifth embodiment.

FIG. 11 is a perspective view of a principal part showing a configuration of an objective lens driving device in the fifth embodiment.

FIG. 12 is an exploded perspective view of an objective lens driving device in a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Objective lens 2 Lens holder 3a, 3b Magnetic yoke 4 Focus coil 5a-5b Tracking coil 6a-6d Elastic member 7 Leaf spring 8a, 8b Magnet 9a-9c Printed board 10 Fixing member 11 Base 20 Optical position sensor 21 Projection part 22 Hole portion 23 Bent portion 24 Fine portion 25 Positioning member F Focus direction T Tracking direction

Claims (10)

[Claims] 1. An objective lens of a device for optically writing or reading information on a disk-shaped recording medium, and a radial direction parallel to a recording medium surface of the disk-shaped recording medium,
A movable part having a mechanism for driving in the optical axis direction perpendicular to the recording medium surface, the movable part including the objective lens and a lens holder holding the objective lens, one end attached to the lens holder and the other end Four substantially parallel elastic members attached to the fixing member, one or a plurality of driving means for driving the movable portion in the radial direction and the optical axis direction, and a base to which the fixing member is attached. The elastic members are arranged such that their longitudinal directions are substantially perpendicular to the optical axis direction and the radial direction, and two adjacent elastic members face each other. An objective lens driving device, which is a part of a square-shaped leaf spring having two sides. 2. The objective lens driving device according to claim 1, wherein the width of the four elastic members is substantially the same as the thickness of the leaf spring. 3. A concave-convex portion or a slit is provided on the lens holder or the fixing member in order to position and fix one of the two sides of the square leaf spring not used as an elastic member to the lens holder and the other to the fixing member, respectively. 2. The objective lens driving device according to claim 1, wherein the leaf spring is provided with a hole, a notch, a fold, or the like that can be fitted into the uneven portion or the slit. 4. A reflection plate for an optical position sensor, comprising an optical position sensor on a base or a fixed portion such as a fixing member for detecting the amount of movement of the objective lens in the optical axis direction or the radial direction. 2. The objective lens driving device according to claim 1, wherein a part of the leaf spring also serves as the shield plate. 5. A fine portion that can be cut is provided on a part of the two sides after the two sides that are not used as elastic members of the square-shaped leaf spring are attached to the lens holder and the fixing member, and then divided into two. The drive means for the optical axis direction and the drive means for the radial direction, the drive coil for the optical axis direction and the drive coil for the radial direction fixed to the lens holder are fixed in the air gap of the magnetic circuit fixed to the base and composed of the magnet and the magnetic yoke. An arranged electrodynamic converter, the leaf spring is formed of a solderable material such as phosphor bronze, beryllium copper, and the respective end portions of the drive coil for the optical axis direction and the drive coil for the radial direction, The elastic member portion of the square leaf spring is used as a part of a lead wire by soldering and fixing to each of the divided portions of the two sides and then cutting the fine portion. Term Or 3 objective lens driving device according. 6. A positioning member having conductivity is used as the convex portion provided on the lens holder or the fixing member,
The objective lens driving device according to claim 5, wherein after the leaf spring is positioned and fixed by the positioning member, the ends of the radial drive coil and the optical axis drive coil are fixed to the positioning member. 7. The positioning member is made of a solderable material such as brass, and the radial direction driving coil and the optical axis direction driving coil are fixed by soldering to the positioning member. 6. The objective lens driving device according to item 6. 8. A positioning member having conductivity is attached to a fixing member to position the leaf spring with respect to the fixing member, and at the same time, a part of the positioning member is soldered and fixed to a printed circuit board. The objective lens driving device according to claim 6. 9. The objective lens driving device according to claim 6, wherein the positioning member is formed integrally with the lens holder or the fixing member. 10. The objective lens driving device according to claim 6, wherein a viscoelastic material such as butyl rubber or silicon rubber is fixed to the elastic member of the square-shaped leaf spring by molding.