JPH042933B2 - - Google Patents

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 an optical information recording/reproducing device.

Conventionally, there have been devices of this type as shown in FIGS. 1 and 2. In the figure, 1 is a holder, 2
a and 2b are outer yokes attached to this holder 1, 3 are outer yokes 2a and 2b and permanent magnets housed in the holder 1, 4 is an inner yoke glued to the holder 1, 5 is a coil, and 6 is a coil 5. 7 is a mirror glued to the coil holder 6, 8 is a support rod that supports the coil holder 6 on the holder 1, and 9 is the coil holder 6 and the support rod 8.
It is a rubber elastic body that supports the mirror 7 in a swingable manner. Next, the operation will be explained using FIG. 2. The mirror 7 is supported by a rubber elastic body 9 via a coil holder 6 so as to swing only in the direction of arrow a. Therefore, the shape of the rubber elastic body 9 is long in the direction perpendicular to the plane of the paper, and has a structure that makes it difficult to swing in the direction perpendicular to the direction of arrow a. In addition, a permanent magnet 3, an outer yoke 2a, and an inner yoke 4 having polarities as shown in the figure
A magnetic circuit is formed by the outer yoke 2b and the outer yoke 2b. The magnetic flux generated by the N and S poles of the permanent magnet 3 passes through the magnetic circuit, and when a current flows through the coil 5, an electromagnetic force proportional to the product of the current value and the magnetic flux interlinking with the coil 5 is generated. As a result, the mirror 7 is swung.

Since the magnetic circuit of the conventional deflection mirror device is configured as described above, the yokes 2a, 2b, 4
In addition, since the permanent magnet 3 is located away from the coil 5, the structure becomes complicated, and the overall size becomes large, making it difficult to downsize and requiring many assembly steps.

The present invention has been made to eliminate the above-mentioned drawbacks of the conventional devices, and an object of the present invention is to provide a deflection mirror device that is small, has a simple structure, and has high mirror drive efficiency.

That is, the mirror deflection device according to the present invention includes: a mirror that reflects a light beam; a support rod that swingably supports the mirror via an elastic member; a holder that holds the support rod; and a drive means for swinging in the direction of
a pair of permanent magnets attached to the holder, magnetized so that opposing surfaces have different polarities, and fixed symmetrically to the support rod; The yoke is mounted and arranged, has a surface facing the magnetic pole surfaces of the pair of permanent magnets at a certain distance, and has a hollow portion such that the support rod penetrates through the center of the yoke and is positioned. It is characterized by comprising the yoke and a coil connected to the mirror and placed in a magnetic atmosphere formed between the pair of permanent magnets and the yoke.

An embodiment of the present invention will be described below with reference to FIGS. 3 to 9. In the figure, 10 is a holder, 11 is a yoke attached to the holder 10, and 1
1a and 11b are positioning holes for positioning the yoke 11 and the holder 10 when the yoke 11 is attached to the holder 10, and 12a and 12b are arranged on the outside of the yoke 11, and the holder is arranged symmetrically with the support rod 8 described later. a permanent magnet attached to 10;
A coil 5 is located between the permanent magnets 12a, 12b and the yoke 11. 6 is a coil holder to which the coil 5 is attached; 7 is a mirror that reflects a light beam adhered to the coil holder 6; 8 is a coil holder 6
A support rod 13 is provided between the coil holder 6 and the support rod 8 to support the mirror 7 on the holder 10, and a rubber (elastic member) 11c is provided to swing the mirror 7 in a certain direction.
is a hollow part of the yoke 11, and the support rod 8 is attached to the hollow part. In the figures, the same numbers indicate the same or equivalent parts.

Next, the operation will be explained. In FIGS. 7 and 8, the permanent magnets 12a and 12b are a pair of two of the same shape in order to miniaturize the magnetic circuit and improve the drive efficiency of the mirror 7, and have a diameter larger than that of the yoke 11. Arrange the concentric circles so that their arcs are facing each other. In particular, the arrangement is such that the north pole side of the permanent magnet 12a and the south pole side of the permanent magnet 12b are opposed to each other.
The permanent magnets 12a and 12b are connected to the cylindrical yoke 11.
It is mounted symmetrically on the holder 10 on a concentric circle having a diameter larger than the diameter of the yoke 11 so that the arc faces to the side. Then, as shown in FIG. 7, a magnetic circuit is formed by the permanent magnet 12a, the yoke 11, and the permanent magnet 12b. Permanent magnets 12a and 1
2b passes through the yoke 11 as shown in the figure. The deflection mirror device shown in FIGS. 3 to 6 is, of course, equipped with the above-mentioned magnetic circuit, and when a current is passed through the coil 5, the mirror 7 moves in the direction indicated by the arrow a depending on the magnitude of the current value. direction, using a part of the elastic member 13 as a fulcrum.

Incidentally, according to the present invention, it is also possible to form a magnetic circuit as shown in FIG. That is, in the previous example, a round mirror was used, but if a square mirror is used and the coil is also configured in a square shape, the permanent magnet and yoke will also be square, and the processing of the permanent magnet etc. will be simplified.

As described above, according to the present invention, the permanent magnet is attached to the outside of the yoke symmetrically with the support rod, and the magnetic pole face of the permanent magnet and the yoke surface facing the magnetic pole face are separated by a certain distance, and By providing a hollow part in the center of the yoke, the support rod can be positioned on the yoke, and the lines of magnetic force generated by the pair of permanent magnets can be concentrated around the yoke, so that a high magnetic flux density can be obtained with a simple configuration. As a result, mirror drive efficiency is improved, and the device can be made smaller and easier to assemble.

[Brief explanation of drawings]

FIG. 1 is an isometric view showing a conventional deflection mirror device;
2 is a sectional view of FIG. 1, FIG. 3 is a front view of a deflection mirror device according to an embodiment of the present invention, FIG. 4 is a side view thereof, and FIGS. 5 and 6 are respectively FIGS. 3 and 6. FIG. 4 is a sectional view, FIG. 7 is a magnetic circuit configuration diagram of the present invention, FIG. 8 is a cut-out diagram of the permanent magnet part, and FIG.
The figure is a cut-out diagram of the yoke part, Figure 10 is another magnetic circuit configuration diagram of the present invention, and Figure 11 is XI of Figure 10.
-XI sectional view. In the drawing, 5 is a coil, 6 is a coil holder, 7 is a mirror, 8 is a support rod, 9 is a rubber elastic body, 10 is a holder, 11 is a yoke, 11a, 11b are positioning holes, 11c is a hollow part, 12a, 12b is a permanent magnet, and 13 is rubber (elastic member). Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A mirror that reflects a light beam, a support rod that swingably supports the mirror via an elastic member,
comprising a holder for holding the support rod and a drive means for swinging the mirror in a predetermined direction, the drive means being attached to the holder and magnetized so that opposing surfaces have different polarities; and a pair of permanent magnets that are fixed symmetrically to the support rod, and a permanent magnet that is attached to the holder and arranged between the pair of permanent magnets, and is spaced a certain distance from the magnetic pole faces of the pair of permanent magnets. a yoke having surfaces facing each other and having a hollow portion such that the support rod passes through the center of the yoke and is positioned; A deflection mirror device comprising: a magnetic field formed in a magnetic field; and a coil disposed in a magnetic field. 2. The yoke has a cylindrical shape, the coil has a cylindrical shape, and the pair of permanent magnets have an arcuate portion on a surface facing the yoke,
2. The deflection mirror device according to claim 1, wherein the arcuate portions of the pair of permanent magnets are arranged concentrically. 3. The shape of the yoke and the pair of permanent magnets is a rectangular parallelepiped, and the coil has a rectangular shape, and the yoke and the pair of permanent magnets are arranged so that two opposing sides thereof are parallel. A deflection mirror device according to claim 1, characterized in that: