JPS6215773Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to an improved movable mirror unit used in optical video discs and the like.

In optical video discs, the optical axis may shift due to uneven rotation or eccentricity of the disc, so it is necessary to track the laser beam to hit the disc. Therefore, as shown in Figure 1, a surface area of about 1 cm ² to 3 cm ² is required. Magnets 5 and 6 are attached to both lower ends of the movable mirror 3.
A movable mirror unit has been proposed in which the mirror is fixed, the middle is supported by a rubber damper 13 and a metal support plate 14, and a coil 2 provided so as to surround the outside of both magnets is energized to cause the mirror to swing. However, with this configuration, adhesion between the rubber damper and the end face of the metal support plate is troublesome, and the rubber damper is provided locally, resulting in lack of stability, and the movable mirror is fixed on the end face of the metal support plate via the rubber damper. Since external vibrations and shocks are transmitted to the movable mirror without being absorbed, there is a drawback that malfunctions are likely to occur. In addition, since the metal support plate and the frame 1 are fixed by caulking into the through hole of the frame body, and the rubber damper is glued to the end face of the metal support plate, there is a disadvantage that assembly is difficult and the number of parts is large. There is.

In view of the above drawbacks, an object of the present invention is to propose a movable mirror unit that prevents external shock from being transmitted to the mirror as much as possible and has a simplified configuration suitable for mass production.

The present invention will be explained below with reference to illustrated embodiments. Second
In the movable mirror unit shown in Figures 1 and 3, a coil 2 is supported on a frame 1, and a rubber holder 4 with a mirror 3 supported is fitted in the center of the frame 1 so that the mirror 3 is positioned within the coil. Bar magnets 5 and 6 are fixed to the lower surfaces of both sides of the mirror 3.

The frame 1 is made of synthetic resin and has a flat plate 1a with a fitting groove 1b in the center, a mounting plate 1c at right angles on one side of the flat plate in the direction of the fitting groove, and a mounting plate 1c on both sides parallel to the fitting groove. Support stands 1d and 1e for the coil 2 are each integrally formed. There is a square recess 1f in the center of the mounting plate 1c.
A through hole 1g is bored in the center of the hole 1g, and a mounting nut or bolt is inserted into the hole 1g. Step portions 1h and 1i are formed on the support stands 1d and 1e.

The mirror 3 is formed in a rectangular shape, and bar magnets 5 and 6 are fixed to the lower surfaces on both sides in the longitudinal direction, and the bar magnets are magnetized with different polarities on the opposite sides and on the outside.

The cross-sectional shape of the rubber holder 4 is Y at the top.
It is divided into two forks 4a and 4b in a character shape, and from the middle to the lower part, a root part 4c that widens toward the lower end is integrally formed. The bifurcated upper surface is adhesively fixed to the longitudinal center lower surface of the mirror 3, and the root portion 4c is attached to the frame 1.
The mirror is press-fitted into the fitting groove 1b and is supported by a rubber holder so as to be able to swing left and right.

The coil 2 is wound into a rectangular shape larger than the surface area of the mirror 3, and the support stands 1d and 1e of the frame 1 are arranged so that the vertical center of the coil 2 coincides with the vertical center of the bar magnets 5 and 6. It is placed on the step portions 1h and 1i.

When the above-mentioned movable mirror unit is assembled and the coil 2 is energized, the magnets 5 and 6 fixed to the mirror 3 are attracted or repelled by the magnetic field formed by the energizing direction of the coil and the current, and the mirror is made of rubber. It is oscillated and displaced against the parallel support force of the holder 4,
Laser light or other light beams directed at the mirror are deflected and reflected.

The fitting groove between the root of the rubber holder and the frame in the above description may be formed by forming a fitting groove in the rubber holder and forming a fitting protrusion in the frame.

Fig. 4 shows a modified example in which the mirror can be swung in the X and Y axes.The root part 4c of the rubber holder 4 is press-fitted into the fitting groove 7a of the intermediate plate 7, and the rubber is attached to the lower center surface of the intermediate plate. A rubber holder 8 having the same shape as the holder 4 is fixed perpendicularly to the rubber holder 4, and its root 8a is press-fitted into the fitting groove 1b of the frame 1. The coil support stands 1d, 1e and the mounting plate 1c extend upward, and the coil support stands 1d, 1e are provided with other coil support steps or grooves 1k, 1m, in which the coil 9 is supported. Other bar magnets 10 and 11 are fixed to the lower surfaces of both sides of the intermediate plate.
As another modification, a rubber holder and a bar magnet are fixed to the orthogonal sides of the lower surface of the frame shown in FIG. , it may be possible to swing in the Y axis. However, the mounting plate 1c is provided on the lower frame.

The present invention is constructed as described above, and in particular uses a rubber holder with a Y-shaped cross section, so the center of rotation of the mirror is set at a fixed position that is the branching point of the Y-shape of the rubber holder. In addition, even if the elastic coefficient of the rubber holder changes due to changes in external temperature, the center of swing of the mirror will not change from the fixed position, making it possible to swing the mirror stably. On the other hand,
As mentioned above, since a rubber holder with a Y-shaped cross section was used, the direction perpendicular to the swing direction, that is, the second
Since sufficient elastic force can be obtained in the vertical direction in the figure, it is possible to provide a movable mirror unit that can effectively absorb shocks from the outside and has excellent practical effects such as improved shock resistance.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a conventional example, FIG. 2 is a front view of the movable mirror unit of the present invention, FIG. 3 is an exploded perspective view of the same, and FIG. 4 is an explanatory diagram of a modified example. 1... Frame body, 1b... Fitting groove, 1d, 1e...
Coil support stand, 2...Coil, 3...Mirror, 4
...Rubber holder, 4c...root, 5,6...bar magnet.

Claims (1)

[Scope of utility model registration request] A mirror with bar magnets fixed to the lower surfaces of both sides is placed inside the coil of the frame supporting the coil, and the mirror is supported by a rubber holder having a Y-shaped cross section so as to be able to swing left and right around the holder. A movable mirror unit consisting of a holder supported by a frame.