JPH02240616A - Optical deflector - Google Patents

Abstract

PURPOSE:To obtain the inexpensive optical deflector while maintaining various good characteristics, such as frequency characteristics and linearity, by using a piece of annular magnet as a magnet of the optical deflector of a moving iron type. CONSTITUTION:This optical deflector is constituted of the annular magnet 11 which is magnetized in a prescribed direction, yokes 12, 13 which are mounted thereto and are provided with tongue pieces 12a, 12b, 13a, 13b forming a pair of single magnetic poles of the magnetic poles on the inner peripheral side thereof, coils 21 which are disposed near a moving iron piece 14 and are disposed on the inner peripheral side of the annular magnet 11, a turning shaft 15 which is fixed with the moving iron piece 14 and is mounted with a mirror 18 at one end and an energizing means 19 which turns and energizes the turning shaft 15 so as to reset the same to a prescribed position. Since the magnet 11 used therein is just one piece in this way, the cost is low and since there is no need for winding the coils 21 on the yokes 12, 13, the production is easy; further, the moving iron piece 14 is directly magnetized by the coils 21 wound near the same and, therefore, the sure operation with a small current is possible.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an optical deflection device for deflecting laser light in, for example, an optical card device.

[Summary of the invention]

The present invention uses a single ring-shaped magnet as a magnet in a so-called moving iron type optical deflection device, thereby making it possible to provide an inexpensive optical deflection device with good characteristics such as frequency characteristics and linearity. It is something.

[Conventional technology]

2. Description of the Related Art In recent years, optical card systems have been put into practical use in which information is recorded at high density on an optical card using a light beam such as a laser beam, and information is reproduced from the optical card on which information is recorded using a light beam.

Among these optical card systems, there is one in which a laser beam emitted from an optical device section is deflected by a rotating mirror to perform scanning for writing and reading signals.

There are so-called moving coil type, moving magnet type, etc. configurations of the optical deflection device for rotating this mirror and deflecting the light, but the moving coil type is heavy and has a limit in frequency characteristics. Moreover, the moving magnet type has the disadvantage of being prone to wire breakage and lacking in reliability.Moreover, like the moving coil type, the moving magnet type is heavy and has limited frequency characteristics, and the disadvantage is that it is difficult to improve the frequency characteristics such as linearity. There is.

Due to these circumstances, the moving iron type is currently the mainstream as the configuration of the optical deflection device.

The configuration of this conventional moving iron type optical deflection device is shown in FIG.

That is, in this optical deflection device, a pair of magnets) (1) and [2] are arranged on the left and right sides, and the N-pole and N-pole and S-pole of both magnets (1) and (2) are arranged. A pair of yokes (3) and (4) are fixed so as to straddle the S pole. Both yokes (3) and (4) have projections (3a), (3b) and (4) that protrude inwardly in a V-shape, respectively.
a) (4b) is formed, and both yokes (3)
and (4) protrusions (3a) (3b) and (4a)
(4b) Corresponding to the tip, there is an iron mover (
A movable iron piece) (5) is provided. This mover (5
) is fixed to the rotating shaft (6) at its center, and is designed to rotate integrally with this rotating shaft (6). A mirror (not shown) is attached to reflect and deflect light such as laser light.

Further, coils (7) and (8) are wound around the center portions of both yokes (3) and (4), respectively, corresponding to the mover (5). The mover (5) is structured to be magnetized by the generated magnetic field.

And this device is in its normal state, i.e. the coil (7) and (
8) is not energized, the mover (5) is in a neutral position between the NS poles in the magnetic circuit formed by left and right magnets (1) and (2), and is in a magnetically balanced state. When a current is passed through the coils (7) and (8) to generate a magnetic field, the mover (5) is magnetized, causing the magnetic balance to collapse and the mover (5) to move towards the rotation axis (6).
It is rotated as one. The rotation of the rotation shaft (6) causes the mirror to rotate, thereby deflecting the light.

Such a moving iron type optical deflection device has good frequency characteristics of operation because the mover (5) is lightweight.
It also has features such as good linearity.

[Problem to be solved by the invention]

However, this conventional optical deflection device uses two magnets, which increases the cost.Moreover, since the coil is wound around a yoke with a complicated shape, it is time-consuming and expensive to manufacture. Furthermore, this conventional device has various problems such as requiring a large current for operation because it has a structure in which the mover is indirectly magnetized by a coil wound around the yoke.

The present invention has been made in view of the above, and an object of the present invention is to provide an optical deflection device that is inexpensive and can be operated reliably with a small current without impairing the characteristics of the moving iron type.

[Means to solve the problem]

In order to achieve the above object, the optical deflection device of the present invention includes a ring-shaped magnet magnetized in a predetermined direction, and a pair of rotating single magnetic poles attached to the ring-shaped magnet on the inner circumferential side thereof. A yoke is provided with a tongue piece that corresponds to the tongue piece of this yoke.

A movable iron piece disposed in a magnetically neutral and balanced position, a coil located near the movable iron piece and disposed on the inner circumferential side of the ring-shaped magnet, and a movable iron piece fixed to one end. The rotating shaft has a mirror attached thereto, and a biasing means for biasing the rotating shaft to return to a predetermined position.

[Effect]

In the optical deflection device of the present invention, a magnetic field is generated by passing a current through the coil, and the movable iron piece is magnetized based on this magnetic field and rotated together with the rotation axis, thereby rotating the mirror. It operates so that the light is deflected. In this optical deflection device, only one magnet is used, so the cost is low, and the coil does not need to be wound around the yoke, making it easy to manufacture.Furthermore, the movable iron piece is directly magnetized by the coil wound nearby. Because of this, it can operate reliably even with small currents.

〔Example〕

Hereinafter, the present invention will be explained in detail with reference to FIGS. 1 to 4.

In the present invention, instead of the two magnets conventionally provided on the left and right, one ring-shaped magnet) (11)
This is a configuration using . In this example, this ring-shaped magnet (11) is magnetized in its thickness direction, that is, the upper surface is the N pole and the lower surface is the S pole.

Ring plate-shaped yokes (12) and (13) corresponding to the ring-shaped magnet (11) are attached to the upper and lower surfaces of the ring-shaped magnet (11).

The upper yoke (12) has a pair of tongue pieces (12a) and (1) on the blade side half thereof, which protrude from the inner peripheral side of the ring-shaped magnet (11) and whose tips are vertically bent downward.
2b) are formed, and the other half of the yoke (13) on the lower surface side is provided with tongue pieces (12a) and (12b).
) A pair of tongue pieces (13a) and (13b) are formed on the inner circumferential side of the ring-shaped magnet [11] and whose tips are bent vertically upward.

The upper and lower yokes (12) and (13) are of the same shape, and are fixed to the upper and lower surfaces of the ring-shaped magnet (Il), respectively, in opposite directions. be.

With this configuration, the tongue piece (
22a and (12b) each have a single N-pole magnetic pole, and a yoke (
A single magnetic pole of S pole is formed in each of the tongue pieces (13a) and (13b) of 13). In addition, this ring-shaped magnet (11) and yoke (12) (13)
is fixedly supported by a fixed part (for example, a housing) by a predetermined fixing means (not shown).

And the tongue piece (12a) of the yoke (12) and (13) attached to this ring-shaped magnet (11)
Corresponding to b) and (13a) and (13b), an iron plate-shaped mover (movable iron piece) (14) is disposed at the center in a magnetically neutral position. This mover (I4)
is fixed to a rotating shaft (15) at its center so as to rotate integrally with this rotating shaft (15).

This rotating shaft (15) has bearings (16) at the upper and lower parts.
) and (17), and is rotatably supported on the fixed part side, and a mirror (18) for reflecting and deflecting light such as laser light is attached to its upper end.

Further, a torsion bar (19) is connected and fixed in the axial direction to the lower end of this rotating shaft (15), and the lower end of this torsion bar (19) is fixed to a fixed seat (20) on the fixed part side. , the rotation axis (
15) is rotatably biased so that the mover (14) always returns to the neutral position.

Further, a coil (21) is arranged on the inner circumferential side of the ring-shaped magnet (11) and is wound vertically so as to surround both sides of the mover (14). The mover (14) is made of M4 construction and is magnetized by the applied magnetic field. This coil (21) is not wound directly around the mover (14), but is supported on the fixed part side by a predetermined fixing means, and prevents rotation of the mover (14). It is wound in a large annular shape around the mover (14) with a predetermined gap to prevent the movement from occurring. In this example, the coil (21) is formed by being divided into left and right parts so as not to interfere with the rotation axis (15), but it is formed without being divided, and the rotation axis (21) is formed on the upper and lower surfaces of the coil. 15) may be formed into a hole through which it passes.

In the optical deflection device as described above, in a normal state, that is, in a state where the coil (21) is not energized, the mover (
14) is the tongue piece (12a) of the yoke (12) and (13)
(12b) and (13a) It is in a neutral position between the NS magnetic poles formed in (13b) and is in a magnetically balanced state.

In this state, when alternating current is applied to the coil <21) and a magnetic field is generated, the mover (14) is magnetized, causing the magnetic balance to collapse and the mover (14) to resist the rotation biasing force of the torsion bar (19). The mirror (18) is thereby rotated and operated to deflect light in a predetermined direction. Also, when the coil (21) is de-energized, the mover (14) moves to the torsion bar (19).
The mirror (18) is rotated back to the neutral position by the rotation biasing force, and the mirror (18) is therefore returned to the initial position.

In the optical deflection device of this example configured as described above, only one ring-shaped magnet (11) is used, so the cost of parts is lower than in the past, which used two magnets. suppressed, and the coil (21
) has the advantage that it is easy to manufacture because it does not need to be wound around a complicated-shaped yoke as in the conventional case, and can be simply wound in an annular shape, reducing manufacturing costs and being able to be manufactured at low cost. Furthermore, in this optical deflection device, the coil (21) is disposed near the mover (14) and has a structure that directly magnetizes the mover (14), so the current flowing through the coil (21) is The mover (14) also has operational advantages, such as smooth rotation of the mover (14) even without a large current, that is, reliable light deflection.

Therefore, this optical deflection device can realize an inexpensive optical deflection device that operates reliably even with a small current while taking advantage of the advantages of the moving iron type, which have good characteristics such as frequency characteristics and duality. be.

Further, FIGS. 5 and 6 show other structural examples of the ring-shaped magnet.

The ring-shaped magnet 1-(31) of this example is magnetized in the circumferential direction, that is, with the center as a boundary, one half of the ring is a north pole and the other half is a south pole. . On the N-pole side and S-pole side of this ring-shaped magnet (31), fan-shaped yokes (32), (33), and (34) are provided on the upper and lower surfaces, respectively.
(35) are mounted facing each other.

At one end of the yokes (32) and (34) attached to the upper surface side, there is a tongue piece (32a>) that protrudes from the inner peripheral side of the ring-shaped magnet (31) and whose tip is bent vertically downward.
and (34a) are formed respectively, and at the other ends of the yokes (33) and (35) attached to the lower surface side, a ring-shaped magnet (31) protrudes from the inner circumferential side and the tip thereof is bent vertically upward. Tongue pieces (33a) and (35a)
are formed respectively. In addition, this upper and lower yoke (3
2) and (33), and (34) and (35) are of the same shape, and are fixed to the upper and lower surfaces of ring-shaped magnet (31) in opposite directions. It is.

With such a configuration, a single N-pole is formed in the tongue pieces (32a) and (33a) of the yokes (32) and (33) fixed to the N-pole side of the ring-shaped magnet (31), respectively. Furthermore, single magnetic poles of the S pole are formed on the tongue pieces (34a) and (35a) of the yokes (34) and (35) fixed to the S pole side, that is, as shown in FIGS. A magnetic circuit similar to the embodiment shown in FIG. 4 is constructed.

In the magnet structure of this example as described above, the four pieces of yokes (32), (33), and (34) and (35) are all simple fan-shaped small pieces, so manufacturing and processing is easy. Since the magnetic resistance is small, it has special effects such as high sensitivity.

Although the embodiments of the present invention have been described above, the present invention is not limited to the configurations shown in these embodiments, and can take various embodiments without departing from the gist of the present invention. It goes without saying that the examples do not define the invention.

〔Effect of the invention〕

As described above, according to the optical deflection device of the present invention, only one magnet is used, so component costs can be kept low, and the coil does not need to be wound around a complicated-shaped yoke as in the past, so it is easy to manufacture. , it is possible to provide an inexpensive optical deflection device, and since the coil is placed near the movable iron piece and has a structure that directly magnetizes the movable iron piece, reliable optical deflection operation can be performed without requiring a large current. It has practical effects.

[Brief explanation of drawings]

Fig. 1 is a perspective view showing an embodiment of the optical deflection device of the present invention, Fig. 2 is a partially omitted plan view of the same, Fig. 3 is a side view of the same, partially cut away, and Fig. 4 is a ring-shaped FIG. 5 is an exploded perspective view of the magnet and yoke, FIG. 5 is a perspective view showing the other side of the ring-shaped magnet and yoke, FIG. 6 is an exploded perspective view of the same, and FIG. 7 is a plan view of a conventional example. In the figure, (11) is a ring-shaped magnet, (12) and (
13) is a yoke, (12a) (12b) and (13a
) (13b) is the tongue piece, (14) is the mover (movable iron piece), (15) is the rotating shaft, (18) is the mirror, (19)
is a torsion bar (biasing means), and (21) is a coil. Agent Hidemori Matsukuma piggybacking example Fig. 7 77 net No. 1 in 1 Fig. 777 Death and yoke d1 disassembly port Fig. 4 Plan view of implementation staff Fig. 2 Fig. 5 Side view of implementation staff 1 Fig. 3 Mc'net York's Iseifuri disassembly port Figure B

Claims (1)

[Claims] A ring-shaped magnet magnetized in a predetermined direction, and a tongue piece attached to the ring-shaped magnet and forming a pair of single magnetic poles of the same magnetism on the inner circumferential side of the ring-shaped magnet. a movable iron piece that corresponds to the tongue of the yoke and is arranged in a magnetically neutral and balanced position; and a movable iron piece that is located near the movable iron piece and is located on the inner peripheral side of the ring-shaped magnet. a coil arranged therein, a rotation shaft to which the movable iron piece is fixed and a mirror attached to one end, and an urging means for rotationally urging the rotation shaft to return to a predetermined position. An optical deflection device comprising: an optical deflection device that operates so that the movable iron piece rotates together with the rotation shaft based on a magnetic field generated by the coil, so that the mirror is rotated.