JPS59191148A - Deflecting mirror device - Google Patents

Abstract

PURPOSE:To make a magnetic circuit simpler and, at the same time, improve the assembling property of the circuit, by fixedly fitting a coil to a mirror which is fitted to a holder through a supporting rod and elastic member and supported by the elastic member under a revolution-free condition and providing a pair of permanent magnets to the outside of the coil under a symmetrical condition. CONSTITUTION:A magnetic circuit is composed only of permanent magnets 3a and 3b arranged in a symmetrical condition and magnetized so that the faces of the magnets 3a and 3b facing to each other have the polarity of N-pole and S- pole, respectively. That is to say, the magnetic circuit can operate sufficiently without using a conventional yoke. A coil 4 is installed between the permanent magnets 3a and 3b. The magnetic flux flows from the magnet 3a to the other magnet 3b. When an electric current is made to flow to the coil 4, a mirror 6 revolves in the direction of the arrow (a) around a part of an elastic member 8. Since the necessity of any yoke is eliminated from the magnetic circuit, a deflecting mirror device which is simple in constitution and has an excellent assembling property is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a deflection mirror device for reflecting a light beam in a predetermined direction in, for example, an optical information recording/reproducing device.

Conventionally, there has been a device of this type as shown in FIG. In the figure, 1 is a holder, and a yoke 2 is attached to the holder. Further, permanent magnets 3a and 3b are attached to the holder and are arranged at symmetrical positions on the outside of the yoke 2. Such a yoke 2 and permanent magnet 3a
, 3b, ] coils are located between the coils 4 and 3b.
It is mounted on the coil holder 5. The coil holder 5 has
Mirror 6 is glued. The mirror 6 bonded to the coil holder 5 in this way has an elastic member 8 made of rubber, for example.
It is supported by a support rod 7 via.

Next, the operation will be explained. The mirror 6 is supported by a C elastic member 8 via a coil holder 5 so as to rotate only in the direction of arrow a. the.

Therefore, the shape of the elastic member 8 is long in the direction perpendicular to the plane of the paper, and has a structure that makes it difficult to rotate in the direction perpendicular to the direction of arrow a. Further, a magnetic circuit is formed by the permanent magnets 3a, '3b a:i and the yoke 2 having polarities as shown in the figure.

In order to miniaturize the magnetic circuit and improve efficiency, the permanent magnets 3a and 3b are made into a pair of two of the same shape and extend along the arc of a circle having a diameter larger than that of the yoke 2. and are arranged to face each other. In this arrangement state, the north pole side of one permanent magnet 3a faces the south pole side of the other permanent magnet 3b. Therefore, in the magnetic circuit, magnetic flux flows from the permanent magnet 3a through the yoke 2 to the permanent magnet 3b. When a current is passed through the coil 4 arranged in this magnetic circuit, the mirror 6 rotates in the direction of arrow a in accordance with the current value, using a part of the elastic member 8 as a fulcrum.

In such prior art, it is desired to realize a deflection mirror device that has a magnetic circuit that is further simplified and that is easy to assemble.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a deflection cooler device that can meet the above-mentioned needs. 'Simply put, this invention configures a magnetic circuit without requiring a yoke. That is, the deflection mirror device of the present invention comprises: 1) a mirror attached to the holder described in a above via a support rod and an elastic member and rotatably supported by the elastic member; and a mirror fixed to the mirror. It is characterized by comprising a coil and a pair of permanent magnets supported by a holder and symmetrically arranged outside the coil.

An embodiment of the present invention will be described below with reference to FIG.

Note that the parts shown in FIG. 2 that correspond to the parts shown in FIG. 1 are designated using the same reference numerals.

Permanent magnets 3a and 3b are symmetrically attached to the holder 1. A coil 4 is arranged inside these permanent magnets 3a and 3b. Coil 41. t, is mounted on a coil holder 5, and a mirror 6 is adhered to this coil holder 5. The coil holder 5 is supported by the holder via a support rod 7 and an elastic member 8 made of rubber or the like.
The mirror 6 is configured to rotate in a fixed direction, that is, in the direction of arrow a, by the elastic member 8.

Note that the shapes of the permanent magnets 3a, 3b and the coil 4 can be changed arbitrarily. For example, the coil 4 may have a cylindrical shape, and the permanent magnets 3a and 3b may have a cylindrical shape.
It can be made into a concentric arc shape. It is also possible to make the shape of the coil 4 and the shape of the permanent magnets 3a, 3b into rectangular parallelepipeds, respectively, and arrange the permanent magnets 3a, 3b parallel to the coil 4.

Next, the operation will be explained. The magnetic circuit is composed only of symmetrically arranged permanent magnets 3a and 3b, and the polarity is such that the polarities of the mutually opposing surfaces of the permanent magnets 3a and 3b are N and S poles, as shown in the figure. It is magnetized to. That is, although the yoke used in the prior art is effective for increasing the magnetic flux density, this is based on the knowledge that sufficient operation is possible even without the use of the yoke. In the magnetic circuit as described above, the coil 4 is arranged between the permanent magnets 3a and 3b.

The magnetic flux will flow from the permanent magnets 3a to 3b. Here, when a current is passed through the coil 4, the mirror 6 rotates in the direction of arrow a in accordance with the current value, using a part of the elastic member 8 as a fulcrum.

As described above, since the present invention uses a magnetic circuit that does not require a yoke, it is possible to obtain a deflection mirror device that is simple in structure and easy to assemble.

[Brief explanation of the drawing]

Figure @1 is a sectional view showing a conventional deflection mirror device. FIG. 2 is a sectional view showing an embodiment of the present invention. In the figure, 1 is a holder, 3a and 3b are permanent magnets, and 4
5 is a coil, 5 is a coil holder, 6 is a mirror, 7 is a support rod, and 8 is an elastic member. Agent Masuo Oiwa

Claims (3)

[Claims] (1) A deflection mirror device that reflects a light beam and deflects the reflected light, comprising: a holder; a mirror attached to the holder via a support rod and an elastic member and rotatably supported by the elastic member; a coil configured to be fixed to the mirror; and a coil supported by the holder and arranged symmetrically on the outside of the coil.
A deflection mirror device comprising a pair of permanent magnets. (2) The deflection mirror device according to claim 1, wherein the coil has a cylindrical shape, and the permanent magnet has an arc shape concentric with the coil. (3) The deflection mirror device according to claim 1, wherein each of the coil and the permanent magnet has a rectangular parallelepiped shape, and the permanent magnet is arranged parallel to the coil.