JPH0362014A - Rotational driving device of mirror for optical disk device - Google Patents

Abstract

PURPOSE:To allow a rapid operation and to prevent the deterioration in performance by disposing hinges near both ends of a movable body in such a manner that the turning center lines of the hinges pass the centroid of the movable body and arraying and connecting a fixing member, the movable body and the hinges in the moving direction of the rotational driving device for the mirror. CONSTITUTION:The hinges 103 are so disposed near both ends of the movable body 109 that the rotating center lines thereof pass approximately the centroid of the movable body 109. The fixing member 104, the hinges 103 and the movable body 109 are arrayed and connected in the moving direction of the rotational driving device A for the mirror. The rapid matching of the rotating center line of the hinges 103 with the centroid position of the rotating body is possible in this way and the rapid operation is possible; in addition, the action of bending moment by the deviation in the centroid is thereby eliminated and the deterioration in the performance as the mirror device is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to an optical disc device, and particularly to a mirror rotation drive device.

(Prior art) A conventional mirror rotation drive device for an optical disk device has a 13th
As shown in the figure, a rotating body 202 supporting a mirror 201
, a hinge 203 that supports this rotating body 202, a fixing member 204 that fixes this hinge 20.3, a coil 205 that is fixed to the rotating body 202, and this coil 20.
It was composed of a magnetic circuit 206 that applies a magnetic field to 5.

By energizing the coil 205, the rotating body 202 is rotated about the hinge 203, and the angle of the mirror 201 can be changed as shown in FIG. 14.

However, the conventional mirror rotation drive device configured as described above has the following problems.

Since the optical disk is usually installed horizontally or vertically, the optical axis of the objective lens is in the horizontal or vertical direction. Therefore, the gonadal direction of the mirror surface of the mirror rotation drive device that controls the inclination of the optical axis is set at an angle of 45 degrees with the horizontal direction in order to bend the optical axis from horizontal to vertical or from vertical to horizontal. Ru. Furthermore, since the direction of the vertical axis P of the hinge 203 coincides with the normal direction of the mirror 201, the hinge 203
As shown in FIG. 13, the vertical axis P of 03 is horizontal and 4
The direction makes a 5 degree angle.

On the other hand, hinges that support movable objects with a small moment of inertia, such as mirrors used in optical disk devices, are made of metal materials because it is necessary to set the mirror's primary natural frequency (rotation mode) to an appropriate value. In this case, the Young's modulus will be too high and the width of the hinge portion will be thinner than the width that can be practically processed.

Therefore, as the material for the hinge part, it is necessary to use a material such as resin or rubber, which has a low Young's modulus but has a large creep. However, when such a resin material is used, as mentioned above, the hinge makes an angle of 45 degrees with the horizontal direction, so the center of rotation of the hinge 203 and the center of gravity G on the rotating body 202 side are Hinge 2 due to misalignment with
A steady bending moment acts on the hinge 203, and the hinge 203 is likely to be deformed due to creep. Therefore, in order to match the center of gravity and the center of rotation so that the center of rotation of the hinge 203 passes through the center of gravity of the rotating body 202, it is necessary to attach an unnecessary weight as a counterweight to the lower part of the mirror surface, and as a result, the rotation The moment of inertia became large, which worsened the drive sensitivity and made it difficult to move quickly.

Further, even if the center of gravity G position and the rotation center position of the hinge 203 coincide, a shearing force acts on the hinge 203 and deformation due to creep still occurs.

These deformations directly lead to changes in the center position of the optical axis, changing the operation of the detector.

This operating range offset is determined by the relative NA (Numerical Aperture) of conventional video equipment.
This was not much of a problem as long as an objective lens with a small numerical aperture (re: numerical aperture) was used.
In an apparatus using an objective lens with a large diameter, the permissible amount of tilt is small, which poses a problem that affects the performance of the entire apparatus.

Furthermore, when the entire mirror rotation drive device is moved quickly for high-speed access, an inertial force as shown in FIG. 15 acts in the opposite direction to the moving direction, and this inertial force bends and deforms the hinge 203. , the rotating body including the mirror 201 causes vibration. In this case, if the position of the center of gravity G and the center of rotation of the hinge 203 are misaligned, vibration will occur accompanied by rotation of the mirror surface.

This rotational vibration is caused by slow rotation of less than 100m5ec, such as in conventional compact disc devices and video disc devices.
In the Xcess Time device, the resonance amplitude was sufficiently small, and the displacement amount could be suppressed to a non-problematic level by applying a current to the coil 205 and returning the mirror to its original position. In devices that achieve such high-speed access, the resonance amplitude becomes large, and normal control operations cannot suppress deformation to a level that does not cause problems.

(Problem to be Solved by the Invention) As described above, the conventional hinge is provided on the back side of the mirror, and the vertical axis direction of the hinge is aligned with the normal direction of the mirror.
Due to the angle between the center of rotation of the hinge and the center of gravity of the rotating body, deformation of the hinge due to creep was likely to occur. Further, even if the center of gravity and the center of rotation coincided, deformation was likely to occur due to shearing force.

Therefore, the present invention was devised in order to solve the above-mentioned problems.The purpose of the present invention is to enable quick movement, reduce changes in the neutral position, and move at high speed. It is an object of the present invention to provide a mirror drive device for an optical disk device that reduces changes in the neutral position of the optical axis even when the optical axis is in the neutral position.

[Structure of the invention]

(Means for Solving the Problems) In order to achieve the above object, the present invention includes a mirror that guides a light beam to be irradiated onto an optical disk, a movable body to which at least this mirror is fixed, and a movable body fixed to a fixed member. In contrast, in a mirror rotation drive device for an optical disk device including a hinge made of an elastic member that rotatably supports the mirror rotation drive device, the first means is that the hinge is disposed near both ends of the movable body.

The second means is that each of the hinges has its rotation center line substantially passing through the center of gravity of the movable body.

The third means is that the fixed member, the hinge, and the movable body are connected in this order in the direction of gravity.

A fourth means is that the fixed member, the hinge, and the movable body are connected in line with each other in the moving direction of the mirror rotation drive device for an optical disk device.

Furthermore, a fifth means is to integrally mold the hinge, at least a portion of the fixed member and at least a portion of the movable body connected to the hinge.

(Function) According to the first means, since the hinge is placed near both ends of the rotating body including the mirror surface, the rotational center line of the hinge can be aligned with the center of gravity of the rotating body, thereby eliminating unnecessary weight. There is no need to add . As a result, it enables quick operation.

In the second method, the effect of bending moment due to the shift of the center of gravity is eliminated.

In the third method, a uniform tensile stress acts on the hinge due to gravity, and no bending moment that causes large local stress acts on the hinge.As a result, creep strain is difficult to develop and the performance as a mirror device deteriorates. is difficult to occur.

In the fourth means, the inertial force that acts when the mirror rotation drive device is driven passes through the longitudinal axis of the hinge, and tensile or compressive stress acts on the hinge portion almost uniformly.

The fifth means is easy to manufacture and assemble.

(Example) Hereinafter, preferred embodiments of the present invention will be described in detail based on the drawings.

FIG. 1, FIG. 2, and FIG. 3 show a first mirror rotation drive device of the present invention.

As shown in the figure, in the mirror rotation drive device A of this embodiment, a mirror 101 is fixed to a rotating body 102, and this rotating body 102 is supported by a hinge 103. The lower end of this hinge 103 is fixed to a fixing member 104.

A coil 105 is fixed to the rotating body 102, and a magnet 1
The rotating body 102 is rotated by electromagnetic interaction with the rotating body 06.

Here, the hinge 103 connects the mirror 101 and the rotating body 1.
02 and the coil 105, and is disposed near both ends of a movable body 109 (on the rotating body side), and is integrally molded with the rotating body 102 and the fixed member 104 by injection molding of resin or the like.

Such integral molding of the hinge 103 makes manufacturing and assembly extremely easy, and also ensures the rigidity of the hinge.

Furthermore, since the hinges 103 are disposed near both ends of the movable body 109 including the mirror 101, the rotating body 102, and the coil 105, the movable body cannot protrude downward between these two hinges 103. This makes it easier to align the center of rotation of the hinge 103 with the center of gravity of the movable body 109, eliminates the need to add unnecessary weight for balance, and allows quick movement.

Furthermore, since the hinges 103 are arranged on both sides of the movable body, as shown in FIG. .

This mirror rotation drive device A is set in the same way as the one shown in FIG. 13, and in the information recording and reproducing apparatus using the linear drive device shown in FIG. It will be installed in both.

(a) The arrow part is the inner space of the pickup head 113 equipped with the objective lens 112 which is a transducer that records or reads information on the optical disc 111 rotated by the spindle motor 110 (12th
figure).

(b) The arrow part is a lower part of the frame 115 that connects the pickup head 113 and the optical system 114 (FIG. 11).

As shown in FIG. 11, the direction of inclination of the mirror 101 is opposite between the arrow part (a) and the arrow part (b). Since each of them (a) can also be tilted,
It becomes possible to install the arrow part and the (b) arrow part.

Note that although two hinges 103 are used here, the same effect can be obtained even if three or more are used.

4, 5, and 6 show a second mirror rotation drive device of the present invention.

As shown in the figure, in this mirror rotation drive device B, the portion 10 of the fixing member 104 of the hinge 103 is
7 is disposed on the opposite side of the earth in the direction of gravity g, that is, on the upper part, and the rotating body side member 108 is disposed on the earth side, that is, at the bottom in the direction of gravity g. It is suspended. Therefore, here, the fixed member 104, hinge 103, and movable body 109 are connected in this order in the direction of gravity. Because of this configuration, only uniform tensile stress due to gravity acts steadily on the hinge 103, and large local stresses such as bending moments do not act on the hinge 103, so distortion due to creep is prevented. is less likely to occur.

This second mirror rotation drive device B is used in the information recording and reproducing apparatus using the linear drive device shown in FIG. 10 (b).
Suitable for installation in the position indicated by the arrow. The arrow part (b) indicates the lower part of the frame 115 that connects the optical system 114 to the pickup radar 113 (the 11th part).
(Figure) This is because the hinge 103 is a stationary part, and only a uniform tensile stress due to gravity can be constantly applied to the hinge 103 to prevent distortion due to creep from occurring.

FIG. 7, FIG. 8, and FIG. 9 show a third mirror rotation drive device of the present invention.

As shown in the figure, in this mirror rotation drive device C, a hinge 10 made of an elastic member that supports a rotating body 102 is used.
3, that is, the portion 107 of the fixed member 104 from the rotating body side member 108 via the hinge 103 in the use state.
A movable body 109 that includes the mirror 103 and the rotary body 102 is aligned with the moving direction (a) of the mirror rotation drive device C, and is located on both sides of the hinge rotation center line.
The structure allows the center of gravity to be located. As a result, the inertial force acting on the movable body 109 including the mirror 101 and the rotating body 102 passes through the hinge longitudinal axis S, and tensile or compressive stress acts uniformly on the hinge 103, causing displacement in the hinge longitudinal axis S direction. Since only a rotation is generated and the displacement is small, there is little deterioration in performance as a mirror device.

This third mirror rotation driving device C is often adopted when the mirror [03] is light, with emphasis on dynamic characteristic changes.

This third mirror rotation drive device C is used in the information recording and reproducing device using the linear drive device shown in FIG. 10 (a).
Suitable for installation in the area indicated by the arrow. This is because, in the arrow part (a), the moving direction of the pick-up rod 113 coincides with the hinge longitudinal axis S, so that the compressive or tensile stress acting on the hinge 103 is made uniform, and the displacement in the hinge longitudinal axis S direction is This is because the deterioration of the performance of the mirror device can be reduced because rotational displacement is eliminated by reducing the amount of rotational displacement.

Of course, the mirror rotation driving device C may be moved in the direction of gravity.

〔Effect of the invention〕

As detailed above, in short, according to the present invention, the following excellent effects are exhibited.

Since hinges are placed near both ends of the movable body including the mirror and the rotating body, quick movement is possible and vibrations in the jitter direction are less likely to occur.

■If the center line of rotation of the hinge passes through the center of gravity of the movable body, there will be no displacement due to bending moment.

■If the movable body is suspended in the direction of gravity by a hinge, the progress of creep at the hinge can be minimized.

■If the fixed member, movable body, and hinge are lined up in the moving direction of the mirror rotation drive device, even when the mirror device is moved at high speed, there will be less deformation due to inertial force, and the performance of the mirror device will deteriorate. There's not much to do.

(2) If the fixing member, the rotating body side member, and the hinge are integrally molded, manufacturing becomes easier and the rigidity of the hinge can be ensured.

[Brief explanation of drawings]

Fig. 1 is a perspective view showing the first embodiment of the present invention, Fig. 2 is a side view taken in the direction of Fig. 1, Fig. 3 is a sectional view taken along the line - - Fig. Perspective view showing the second embodiment of the invention, No. 5
The figure is a side view in the direction of arrow V in figure 4, and figure 6 is a side view in the direction of arrow V in figure 5.
7 is a perspective view showing the third embodiment of the present invention, FIG. 8 is a side view taken in the direction of the arrow in FIG. 7, and FIG. 9 is a sectional view taken along the line IX-IX in FIG. FIG. 10 is a plan view of an optical disk device in which a mirror rotation drive device according to each of the above embodiments is installed;
Figure 11 is a schematic diagram of the section taken along line XI-XI in Figure 10, and Figure 1.2.
The figure is an exploded perspective view of the essential parts of the optical disk device, FIG. 13 is a longitudinal sectional view of a conventional mirror rotation drive device, and FIGS. 14 and 15 are operational views of the conventional mirror rotation drive device. A-B-C・・Mirror rotation drive device 101・・Mitsu- 102・・Rotating body 103・・Hinge 104・・Fixed member 107・・Fixed member portion 108・・Movable part side member 109・・Movable body

Claims (5)

[Claims] (1) An optical disc comprising a mirror that guides a light beam to be irradiated onto the optical disc, a movable body to which at least the mirror is fixed, and a hinge made of an elastic member that rotatably supports the movable body with respect to the fixed member. A mirror rotation drive device for an optical disc device, characterized in that the hinge is arranged near both ends of the movable body. (2) The mirror rotation drive device for an optical disk device according to claim 1, wherein the rotational center line of each of the hinges substantially passes through the center of gravity of the movable body. (3) The mirror rotation drive device for an optical disc device according to claim 1 or 2, wherein the fixed member, the hinge, and the movable body are connected in this order in the direction of gravity. (4) Claims 1, 2, and 3 are characterized in that the fixed member, the hinge, and the movable body are connected in parallel in the moving direction of the mirror rotation drive device for an optical disk device.
The mirror rotation drive device for an optical disk device as described above. (5) Claims 1 and 2, characterized in that the hinge, at least a part of the fixed member and at least a part of the movable body connected to the hinge are integrally molded.
4. The mirror rotation drive device for an optical disc device according to 3 or 4.