JP2004152402A - Optical system driving device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a small type and high performance optical system driving device. <P>SOLUTION: In the optical system driving device comprising, at least, a holder 4 with an optical element for focusing a light beam, a carriage 1 for supporting the holder 4 to be movable in the direction almost perpendicular to or radial to a recording medium, a moving means for supporting the carriage 1 to be movable almost radial to the recording medium, a reflecting mirror 9 which is installed on the carriage 1 and alters the direction of the light beam, and a cover 11 for locally or completely enclosing it on the carriage 1, the carriage 1 is provided with a presser member 15 of which one end is is locked to the carriage and the other end is held between the cover 11 and the carriage 1, and which fixedly holds the reflecting mirror 9 by elastically pressing it onto the carriage 1 at the fulcrum of the locked part. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an optical system driving device suitable for supporting and driving an optical system for projecting a light beam on an information recording medium in an optical information recording and / or reproducing apparatus such as an optical disk.
[0002]
[Prior art]
An optical information recording and / or reproducing apparatus needs to drive an optical element such as an objective lens in the vertical direction or the radial direction while following the surface deflection or inclination of the optical disk. The optical element and holder are resiliently supported to allow the recording medium to move in a substantially vertical direction, while the optical element and the holder are incorporated in a carriage that can move along the recording medium in a substantially radial direction. Has become.
[0003]
Such a carriage is usually formed of a synthetic resin, and in addition to the optical element and the holder, an actuator for moving the optical element together with the holder in the vertical direction of the recording medium and a light beam incident on the carriage are provided. A reflection mirror or the like for changing the direction of the carriage is disposed, and a metal cover for increasing the rigidity of the carriage is mounted around the reflection mirror (see, for example, Patent Document 1).
[0004]
[Patent Document 1]
JP-A-9-54960.
[0005]
By the way, the above-mentioned driving device has the following problems.
[0006]
Of the members arranged in the carriage, the reflection mirror is fixed to the base using an adhesive, but the carriage itself moves in substantially the radial direction of the recording medium, so that it is inevitable that vibration is applied, In addition, it is not unusual for the temperature of the driving device to exceed 50 ° C. during the operation of the driving device due to the influence of a coil, an electric circuit, and the like installed along with the carriage, and further, an optical system driving device incorporating the carriage is provided. Since the equipment is used in various environments such as high temperature, low temperature, and high humidity depending on the application, there is a disadvantage that the adhesive strength of the adhesive for fixing the reflection mirror is reduced and the position of the reflection mirror is shifted or dropped. was there.
[0007]
The reflection mirror is an optical component, and unlike other components, precise position accuracy of 0.1 degrees is required when angled to achieve accurate recording and reproduction. Therefore, there is a concern that the displacement or dropout of the reflection mirror becomes more remarkable because the bonding area becomes smaller accordingly.
[0008]
In addition, the carriage is often made of synthetic resin in order to reduce the size, weight, and cost, but since the rigidity of the carriage is inevitably reduced compared to the case where the carriage is manufactured by aluminum die casting, the carriage and the holder are driven. In the case of controlling, a sufficient control band cannot be obtained, and there is a limit in improving the performance of such a device.
[0009]
In this regard, in Patent Document 1 described above, the rigidity is increased by providing a reinforcing cover on the carriage. However, the control required by the optical system driving device due to the improvement of the recording density and the increase of the rotation speed of the recording medium. In the current situation where wider bandwidth is required, simply installing a cover is not enough.
[0010]
[Problems to be solved by the invention]
An object of the present invention has been made in view of the above circumstances, and an object of the present invention is to propose a compact and high-performance optical system driving device.
[0011]
[Means for Solving the Problems]
The present invention provides a holder including an optical element for converging a light beam, a carriage 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 a method for moving the carriage in a substantially radial direction of the recording medium. An optical system driving device having at least a moving means for movably supporting, a reflecting mirror installed on a carriage to change the direction of a light beam, and a cover that locally or entirely surrounds the carriage.
The carriage has a holding member that locks one end to the carriage, clamps the other end between the cover and the carriage, and elastically presses the reflection mirror toward the carriage with the locking portion as a fulcrum to fix and hold the reflection mirror. An optical system driving device characterized in that:
[0012]
Preferably, the cover is made of a metal material, and the cover and at least one metal member in contact with the cover are annularly arranged to form a partitioned area, and the carriage is arranged in the partitioned area.
[0013]
The holding member is made of a metal material, and a part of the holding member constitutes a metal member.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described more specifically with reference to the drawings.
[0015]
1 to 5 show a first embodiment of the present invention. FIG. 1 is an external perspective view, FIG. 2 is a front view, FIGS. 3 and 4 are exploded perspective views of main parts, and FIG. 5 is a cross-sectional view of a main part.
[0016]
1 to 3, reference numeral 1 denotes a carriage, and 2 denotes a moving unit that supports the carriage 1 so as to be movable in a substantially radial direction of the recording medium. The moving unit 2 includes a tracking coil, a through hole, a shaft, an inner yoke, and a short circuit to be described later. It consists of a ring, magnet and outer yoke.
[0017]
1, 3, 4, and 5, reference numeral 3 denotes an optical element such as an objective lens that converges a light beam; 4, a holder that supports the optical element 3 (see reference numeral 4 in FIG. 5 for details); Reference numeral 5b denotes a focus coil adhesively fixed to a side wall of the holder 4 and connected to an external electric board; 6a and 6b plate springs; 7 a receiving member adhesively fixed to the carriage 1; It is elastically supported by the receiving member 7 via the leaf springs 6a and 6b so as to be movable (Z direction in the figure).
[0018]
In FIG. 5, 8a and 8b are concave portions provided on the receiving member 7 and filled with silicone gel for damping the leaf springs 6a and 6b, and 9 is a reflecting mirror which is fixed to the inclined base 1a of the carriage 1 and changes the direction of the light beam. Reference numerals 10a and 10b denote tracking coils (for example, those wound with copper-clad aluminum wires for weight reduction) fixed to the outer surface of the carriage 1 and connected to an external electric board, and 11 denotes a carriage leaving the optical element 3 A cover (made of, for example, stainless steel SUS316L having high rigidity and nonmagnetic) covering the upper surface and both side surfaces of 1, and a plate (made of the same material as the cover 11) disposed on the bottom surface of the carriage 1 ), And all of the tracking coils 10a and 10b, the cover 11, and the plate 12 are adhesively fixed to the carriage 1.
[0019]
Reference numeral 13 in FIGS. 1 to 5 denotes a plate fixed to the cover 11 and serving as a weight (a brass C2801 or the like having a large specific gravity can be applied), and 14 in FIG. 4 denotes the tracking coils 10a and 10b and the carriage 1. A plate disposed between the plates to prevent the adhesive for fixing the tracking coils 10a and 10b from flowing into the carriage 1. Reference numeral 15 in FIGS. 4 and 5 fixes the reflection mirror 9 to the inclined base 1a of the carriage 1. It is a holding member. The holding member 15 can be made of, for example, a copper spring material, and includes a main body frame 15b having pressing pieces 15a that come into contact with the four corners of the surface of the reflection mirror 9, and an end provided at one end of the main body frame 15b. A locking piece 15c having a claw portion and a folded double-folded holding piece 15d provided at the other end opposite to the locking piece 15c are provided, and the claw portion of the locking piece 15c is moved by a carriage. 1 and is locked by inserting it into the hole provided in the carriage 1, and holding the holding piece 15d at the other end between the cover 11 and the carriage 1 so that the reflection mirror 9 faces the inclined base 1a of the carriage 1 with the locking portion as a fulcrum. And is elastically pressed and fixedly held. FIG. 6 is a perspective view showing the appearance of the pressing member 15.
[0020]
2 to 4, reference numerals 16a and 16b denote through-holes provided in the carriage 1. Bearings are formed in the through-holes 16a and 16b, respectively. The bearings are shown in FIGS. The shafts 17a and 17b are arranged as described above, so that the carriage 1 can move along the shafts 17a and 17b.
[0021]
Reference numerals 18a and 18b in FIGS. 1 to 3 denote inner yokes arranged inside the tracking coils 10a and 10b. On the outside thereof, copper short rings 19a and 19b having a thickness of about 0.2 mm are attached by caulking. On the inner yokes 18a and 18b (on the recording medium side in the Z + direction in the drawing), outer yokes 21a and 21b to which magnets 20a and 20b are adhered and fixed are arranged.
[0022]
The outer yokes 21a and 21b are fixed to a deck base (not shown) via the inner yokes 18a and 18b, and the tracking coils 10a and 10b, the through holes 16a and 16b, the shafts 17a and 17b, the inner yokes 18a and 18b, Rings 19a, 19b, magnets 20a, 20b, and outer yokes 21a, 21b combine to form a moving means 2 for supporting the carriage 1 so as to be movable in a substantially radial direction of the recording medium.
[0023]
Hereinafter, the operation of the above embodiment will be described.
[0024]
A light beam (laser light) B emitted from a fixed optical system (not shown) passes through a hole 1b provided in the carriage 1 and a hole 7a provided in the receiving member 7, as shown in FIG. The direction is changed by the reflection mirror 9 and a spot is formed on a recording medium (not shown) by the optical element 3.
[0025]
The light beam reflected from the recording medium passes through the optical element 3 again and returns to the fixed optical system, where a focus error, a tracking error, and a recording signal are detected.
[0026]
When a focus error is detected, current flows through the focus coils 5a and 5b, and the holder 4 is directed substantially perpendicular to the recording medium by a leakage magnetic field from the tangential (Y direction) end surface of the magnets 20a and 20b of the recording medium. Driven.
[0027]
When a tracking error is detected, an electric current is applied to the tracking coils 10a and 10b to receive a driving force from a normal magnetic cap between the magnets 20a and 20b and the inner yokes 18a and 18b. Are driven in a substantially radial direction of the recording medium.
[0028]
Also when accessing different tracks, a current flows through the tracking coils 10a and 10b, and the holder 4 is driven together with the carriage 1 in a substantially radial direction of the recording medium.
[0029]
According to the above procedure, the focus control, the tracking control, and the access control are performed on the holder 4 and the optical element 3 fixed and held therein.
[0030]
In the embodiment of the present invention, the reflection mirror 9 is fixed to the carriage 1 by using the pressing member 15, so that the vibration and the coil caused by the operation of the carriage 1 compared with the conventional structure in which only the adhesive is fixed are used. No stress is applied to the adhesive due to the influence of the heat or the environment of the place where the apparatus is used, so that the position of the reflecting mirror 9 does not shift or fall off, and accurate recording and reproduction can be realized.
[0031]
The holding member 15 holds the holding piece 15 d between the cover 11 and the carriage 1 and fixes the holding piece 15 d between the cover 11 and the carriage 1. The mounting work can be performed in such a way that it can be mounted, and the workability during mounting is good. By using the cover 11 to fix the pressing member 15, the reflecting mirror 9 is not easily displaced or falls off the carriage 1, and the installation position of the reflecting mirror 9 is stabilized.
[0032]
The holding member 15 may be made of a metal material, but may be made of a synthetic resin. Further, the reflection mirror 9 may be fixed only with the holding member 15 without using an adhesive. It is possible, and there is no limitation in this respect.
[0033]
FIG. 7 shows another configuration example of the holding member 15. The locking piece 15c of the pressing member 15 may be formed in a simple key shape, and the holding piece 15d may be formed in a shape without being folded.
[0034]
In the embodiment of the present invention, as shown in FIG. 2, metal members such as the cover 11, the tracking coils 10a and 10b, and the plate 12 are annularly arranged to form the divided area M by such a member. By forming the divided area M and disposing the carriage 1 therein, even if the carriage 1 is made of a synthetic resin that is advantageous for reducing the weight, the rigidity of the entire apparatus can be increased, so that a high-performance optical system with a wide control band is provided. A driving device can be provided.
[0035]
Generally, the metal-to-metal bonding force is stronger than the bonding force when the synthetic resin and the metal are bonded with an adhesive, but the metal member and the carriage 1 are bonded and fixed.
[0036]
The tracking coils 10a and 10b are driving sources for driving the carriage 1, and oscillate when an electric current flows. However, the tracking coils 10a and 10b The vibration of 10b is also suppressed and the control band is expanded as a result of the small resonance.
[0037]
8 and 9 show a second embodiment of the present invention. FIG. 8 is an external perspective view of an exploded state, and FIG. 9 is a cross section of a main part.
[0038]
8 and 9 show the arrangement in which the plate 21 extending in the longitudinal direction (X direction) of the carriage 1 is arranged instead of the plate 12 extending in the width direction (Y direction) of the carriage 1 (others). Is substantially the same as that of the first embodiment), and one end of the plate 21 is provided with an erecting piece 21a which is integrated with the plate 21 and is adhered to the rising cover 11 along the end face of the carriage 1. The end is bonded to the locking piece 15c of the holding member 15.
[0039]
The plate 21 can be made of a non-magnetic stainless steel plate, whereby the carriage 1 is surrounded on all sides by a metal member, the rigidity of the apparatus is further increased, and the control band is increased. A wide high-performance optical system driving device can be obtained.
[0040]
When the reflection mirror 9 vibrates with the vibration of the carriage 1, the light beam passing through the reflection mirror 9 also vibrates, and a vibration component is added to the signal. In consideration of the control band, the reflection mirror 9 is higher than other components. Although it can be said that the influence of the vibration is great, in the above configuration, the holding member 15 is firmly fixed by bonding the other end of the plate 21 to the locking piece 15c of the holding member 15, and the ring of the metal member is used. As a result of being reinforced and the rigidity of the portion being particularly improved, the vibration of the reflection mirror 9 is suppressed, and the control band can be significantly expanded.
[0041]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, the position shift of a reflection mirror which changes the direction of a light beam, or falling off can be prevented reliably.
[0042]
Further, according to the present invention, since the carriage is disposed in the partitioned area formed by the annular arrangement of the metal members, the rigidity of the apparatus itself can be increased, and the control band is significantly expanded to improve the performance. be able to.
[Brief description of the drawings]
FIG. 1 is an external perspective view of a first embodiment of the present invention.
FIG. 2 is a front view of FIG.
FIG. 3 is a view showing a disassembled state of the device shown in FIG. 1;
4 is an exploded perspective view of a main part 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 holding member.
FIG. 7 is an external perspective view showing another configuration example of the pressing member.
FIG. 8 is an external perspective view of a second embodiment of the present invention.
9 is a diagram showing a cross section of a main part of the device shown in FIG. 8;
[Explanation of symbols]
REFERENCE SIGNS LIST 1 carriage 1a inclined base 1b hole 2 moving means 3 optical element 4 holder 5a focus coil 5b focus coil 6a leaf spring 6b leaf spring 7 receiving member 8a recess 8b recess 9 reflecting mirror 10a tracking coil 10b tracking coil 11 cover 12 plate 13 plate 14 plate 15 pressing member 15a pressing piece 15b main body frame 15c locking piece 15d holding piece 16a through hole 16b through hole 17a shaft 17b shaft 18a inner yoke 18b inner yoke 19a short ring 19b short ring 20a magnet 20b magnet 21a outer yoke 21b outer yoke B Light beam M Section area

Claims (3)

A holder including an optical element for converging a light beam, a carriage supporting the holder so as to be movable in a substantially vertical direction and / or a substantially radial direction of the recording medium, and supporting the carriage so as to be movable in a substantially radial direction of the recording medium. An optical system driving device having at least a moving means, a reflecting mirror installed on the carriage to change the direction of the light beam, and a cover that locally or entirely surrounds the carriage.
On the carriage, a pressing member is disposed which locks one end to the carriage, clamps the other end between the cover and the carriage, and elastically presses the reflecting mirror toward the carriage with the locking portion as a fulcrum to fix and hold the reflecting mirror. An optical system driving device characterized by the above-mentioned. The apparatus according to claim 1, wherein the cover is made of a metal material, and the cover and at least one metal member contacting the cover are annularly arranged to form a defined area, and the carriage is arranged in the defined area. 3. The apparatus according to claim 1, wherein the holding member is made of a metal material, and a part of the holding member is a metal member.

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