JPH11202226A - Light deflector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light deflector small in size, low in price and capable of stably two-dimensionally scanning light without being affected by external vibrations. SOLUTION: This deflector is provided with a movable plate 101 capable of forming a reflecting plane 112 for reflecting light onto at least one side, a torsional/flexible spring 102 freely torsionally deformable and flexibly deformable while elastically supporting the movable plate 101, a driving coil 106 capable of conducting a prescribed current while being formed on the movable plate 101, and a permanent magnet 104 capable of acting a prescribed magnetic field on the driving coil 104. In this case, the movable plate 101 is displaced in torsional direction and flexible direction by the mutual operation of the electrified driving coil 106 and permanent magnet 104, and the center of gravity on the movable plate 101 is almost matched with the axis A of torsional center of the torsional/flexible spring 102.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical deflector for reflecting light from a light source and scanning the reflected light two-dimensionally.

[0002]

2. Description of the Related Art For example, see the document "Koji Yada, Functional Materials 16
(1996), 68-73 "is known. This optical deflector is, as shown in FIG. 16, a resonance system comprising a torsion / flexure spring 1002 and a trapezoidal movable portion 1004. 1005, a symmetrical reflecting mirror 1003 provided on the movable part 1004, and a piezoresistive element 1001.
00 is formed integrally by processing. The movable portion 1004 is formed asymmetrically, and its center of gravity is set at a position eccentric from the torsion center axis of the torsion / flexion spring 1002.

According to such an optical deflector, when an appropriate voltage waveform is applied to the piezoresistive element 1001, the piezoresistive element 1001 expands and contracts according to the amplitude of the voltage waveform.
The force generated when the piezoresistive element 1001 expands and contracts is applied to the movable part 100 via a torsion / flexure spring 1002.
4 is transmitted. At this time, the movable portion 1004 flexes and vibrates in a direction perpendicular to the paper surface of the drawing, and at the same time, vibrates around the torsion center axis of the torsion / flexion spring 1002. As a result, the movable unit 1004 performs two-dimensional driving to drive the reflecting mirror 1003 in the two-dimensional direction, thereby causing the reflected light from the reflecting mirror 1003 to perform two-dimensional scanning.

[0004]

However, in the above-described conventional optical deflector, the center of gravity of the movable portion 1004 is not set on the torsion center axis of the torsion / flexion spring 1002. Therefore, the center of gravity of the movable part
There is a problem that the movable portion 1004 is more susceptible to external vibrations than other resonance systems set on the torsion center axis of the flexure spring.

In order to simultaneously generate flexural vibration and torsional vibration (ie, for two-dimensional driving),
The movable part 1004 is formed asymmetrically. For this reason, when the optical deflector is housed in any container, the movable unit 1
A large accommodating space corresponding to the outer shape of 004 (particularly, an asymmetrically formed portion) must be ensured in the container. As a result, the dimensions of the container are enlarged and deformed, and the container is enlarged.

In order to reduce the size of the container, the movable part 100
4 is formed substantially symmetrically with respect to the center axis of the torsion,
What is necessary is just to make the outer shape of 003 and the movable part 1004 coincide. However, in such a configuration, in order to simultaneously generate flexural vibration and torsional vibration in the movable portion 1004, a very difficult and complicated configuration is required due to its principle and structural problems, and the manufacturing cost of the device increases. New problems such as

The present invention has been made to solve such a problem, and an object of the present invention is to provide a small, low-power, stable two-dimensional scanning of light without being affected by external vibration. It is to provide an inexpensive optical deflector.

[0008]

In order to achieve the above object, an optical deflector according to the present invention comprises a movable plate capable of forming a reflecting surface for reflecting light on at least one surface, and a movable plate having a movable surface. A cantilever that is elastically supported and is capable of bending and deforming simultaneously with torsional deformation, a drive coil formed on the movable plate and capable of supplying a predetermined current, and applying a predetermined magnetic field to the drive coil. A magnetic field generating means capable of displacing the movable plate in a bending direction along with a torsion direction by an interaction between the energized drive coil and the magnetic field generating means. Substantially coincides with the torsion center axis of the cantilever.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an optical deflector according to a first embodiment of the present invention will be described with reference to FIGS. 1A is a perspective view of the optical deflector according to the present embodiment, FIG. 1B is a cross-sectional view taken along line bb of FIG. 1A, and FIG. is there.

As shown in FIGS. 1 and 2, the optical deflector according to the present embodiment has a movable plate 101 and a torsion member that elastically supports the movable plate 101 and that is capable of being simultaneously deformed and flexibly deformed. A flexure spring 102, and a support 111 that supports the torsion / flexure spring 102,
The movable plate 101, the torsion / flexion spring 102, and the support 111 are integrally formed by a general semiconductor manufacturing process.

The support member 111 is fixed to the support member 110 by a predetermined fixing method (for example, screwing, bonding), and the support member 110 has a hollow rectangular shape. Then, by fixing the support 111 to the support member 110, the movable plate 101 elastically supported by the torsion / flexion spring 102 can be displaced in the flexure direction simultaneously with the torsion direction. It will be supported by the support member 110.

The support member 110 has a permanent magnet 10 used for torsional vibration and flexural vibration of the movable plate 101.
4 is fixed by a predetermined fixing method (for example, screwing, bonding).

In this embodiment, as an example, the permanent magnet 104 is fixed parallel to and opposed to the side CD of the movable plate 101. The movable plate 101 is formed symmetrically with respect to the torsion center axis A of the torsion / flexion spring 102, and its center of gravity coincides with the torsion center axis A.
As a result, an operational effect is produced in which the torsional vibration of the movable plate 101 hardly occurs in response to external vibration.

The main material of the movable plate 101 is preferably a material whose reflective surface is not deformed during vibration (for example, high-rigidity material such as single crystal silicon, silicon nitride, and aluminum).

In the optical deflector of the present embodiment integrally formed by a semiconductor manufacturing process, the movable plate 101
And the support 111 are provided on the single crystal silicon substrate 103.
The torsion / flexure spring 102 is formed by laminating a silicon nitride layer 105, a first polyimide layer 113, and a second polyimide layer 114.
And the second polyimide layer 114. Note that during the manufacturing process of the torsion / flexion spring 102, the single crystal silicon substrate 103 is partially etched away by using the silicon nitride layer 105 as a mask, and in the subsequent processing, the silicon nitride layer 105 is also removed. It has been partially removed.

In the optical deflector having such a laminated structure, an aluminum driving coil 106 having contact pads 107 at both ends extends on the upper surface of the silicon nitride layer 105 constituting the movable plate 101. The upper surface of the first polyimide layer 113 is twisted from the support 111.
An aluminum current supply wiring 108 extending through the flexible spring 102 is formed.

The current supply wiring 108 has a torsion center axis A
And first and second wirings 108-1 and 108-2 arranged symmetrically and in parallel with respect to. An electrode 109 is formed at the base end of each of the first and second wirings 108-1 and 108-2, and the front end thereof is connected to the contact pad 107 via the first polyimide layer 113, respectively. It is connected.

The silicon nitride layer 105 is used as an insulating material between the single crystal silicon substrate 103 and the driving coil 106, and the first polyimide layer 113 is formed between the driving coil 106 and the current supply wiring 108. It is used as an insulating material between them. The drive coil 106 and the current supply wiring 108 are connected to the first and second polyimide layers 113 and 1.
By isolating the electrical element from the outside, deterioration due to oxidation of the electrical element can be prevented.

The semiconductor manufacturing process applicable to this embodiment will be briefly described. The above-described optical deflector, except for the permanent magnet 104 and the support member 110, is collectively formed by a series of semiconductor manufacturing processes. Can be manufactured. For example, after the silicon nitride layer 105 is formed by a plasma CVD method, patterning is performed by photolithography. First polyimide layer 113
Is formed by a spin coating method or a printing method. The aluminum drive coil 106 and the current supply wiring 108 are formed by sputtering, and then subjected to photolithography in a predetermined shape. The single crystal silicon substrate 103
The silicon nitride layer 105 is used as a mask for etching with a strong alkaline etchant (eg, an aqueous solution of potassium hydroxide).

If such a semiconductor manufacturing process is used, portions other than the permanent magnet 104 and the support member 110 can be integrally formed.
At the time of assembly, it is possible to avoid such a situation that the positional relationship between the components becomes incorrect.

FIG. 1B shows the movable plate 101.
It is possible to form a reflecting surface 112 for reflecting light over the entire lower surface of the light emitting device. As a result, since the movable plate 101 has no useless portion that does not contribute to reflection, the outer dimensions of the movable plate 101 can be designed to be the smallest size required by the reflection surface 112, and a miniaturized optical deflector is provided. Can be provided.

In this embodiment, the movable plate 10
The polished surface of the single-crystal silicon substrate 103 constituting the reflection surface 112 on the back surface side of the substrate 1 can be used as it is as the reflection surface, thereby saving processing time and material for forming the reflection surface. . Also, for example, a wavelength of 65
When a laser beam of about 0 nm is reflected, a material having a higher reflectance than single crystal silicon (for example, aluminum)
Is preferably formed on the reflection surface 112.

The hollow rectangular support member 110 is made of soft iron as a main material. In this case, the support member 110 may be formed integrally with a container (not shown) for packaging the optical deflector. The container is formed by, for example, a molding technique. According to this configuration, the number of parts is substantially reduced by one, so that the manufacturing process can be simplified. In addition, since the support member 110 also serves as a back yoke of the permanent magnet 104, an effect of efficiently applying a magnetic field generated from the permanent magnet 104 to the drive coil 106 is generated.

The material of the support member 110 may be, for example, aluminum or plastic in addition to soft iron, but in this case, the back yoke does not function. However, when aluminum or plastic is used, since the specific gravity is smaller than that of soft iron, the effect of reducing the weight of the optical polarizer is produced.

The driving coil 106 is provided on the movable plate 101.
Are arranged in parallel with each other (four and a half in this embodiment) along the four sides CC ′, C′-D ′, D′-D, and DC. The distance c between the drive coils 106 extending parallel and oppositely along ′ and the distance d between the drive coils 106 parallel and oppositely extending along the side DD ′ have different lengths. Has become.

For this reason, the drive coils 106-2 for the second to fourth turns extending in parallel and oppositely along the side CD.
The length of １０６106-4 is asymmetric about the torsion center axis A.

In the present embodiment, as an example, the side C
2nd to 4th parallel and oppositely extending along -D
The lengths of the drive coils 106-2 to 106-4 in the lap are respectively
With the torsion center axis A as the center, the D side is shorter than the C side.

Then, the drive coils 106-2 for the second to fourth turns extending in parallel and oppositely along the side CD are provided.
In 106-4, the difference in length between the C side and the D side with respect to the torsion center axis A decreases in order from the second round to the fourth round. As a result, the total length of the drive coils 106-1 to 106-4 on the C side is longer than the total length of the drive coils 106-1 to 106-4 on the D side.

The permanent magnet 104 and the support member 1
The magnetic field generated by the magnetic circuit including 10 acts strongly as the length of the drive coil 106 facing the permanent magnet 104 increases.

In this embodiment, the total length of the drive coils 106-1 to 106-4 on the C side with respect to the torsion center axis A is the length of the drive coils 106-1 to 106-4 on the D side. It is longer than the total. As a result, based on Fleming's left-hand rule, the C-side drive coils 106-1 to 106-4
Is applied to the D side drive coils 106-1 to 106-4.
Larger than the force acting on the Therefore, the movable plate 10
1 can be given a torsional vibration about the torsion center axis A.

Next, the operation of the optical deflector of this embodiment will be described. Current supply wiring 1 from a pair of electrodes 109
When an alternating current is applied to the torsion coil 08, the drive coil 106 generates a force proportional to the alternating current value in the bending direction of the torsion / flexion spring 102 by the magnetic action generated from the permanent magnet 104 (that is, by Fleming's left-hand rule). receive. As a result, the movable plate 101 deflects and vibrates at a predetermined cycle.

At this time, simultaneously, the force acting on the drive coil 106 is C
It is larger than the side. As a result, the movable plate 101 undergoes torsional vibration.

As described above, since the flexural vibration and the torsional vibration are simultaneously generated, the movable plate 101 can be driven in the two-dimensional direction. According to the present embodiment, the movable plate 101 can be formed symmetrically so that the outer shape matches the reflection surface 112, and the center of gravity of the movable plate 101 can be matched with the torsion center axis of the torsion / flexure spring 102. Therefore, light can be stably emitted without being affected by external vibration.
A small and inexpensive optical deflector capable of performing dimensional scanning can be provided.

Further, according to the present embodiment, the permanent magnet 1
04 is a quadrangle, which is suitable for packaging in a general case.
Since only one is required, space saving can be realized.

The present invention is not limited to the first embodiment but can be arbitrarily changed. For example, assuming that the natural frequency of the torsional signal of the movable plate 101 is Ft and the natural frequency of the flexural vibration is Fb, the alternating current flowing through the pair of electrodes 109 has a sine wave of the frequency Ft and a sine wave of the frequency Fb. It may be synthesized.
With this setting, it is possible to efficiently vibrate the movable plate 101 in the twisting direction and the bending direction.

The number of turns of the drive coil 106 is not limited to four and a half, and the same operation and effect can be realized even if the number of turns is changed to another. Further, it is preferable that a portion of the drive coil 106 extending in parallel with and opposed to the side CD is as close to the edge of the movable plate 101 as possible. With such a configuration, the torsion / flexion spring 10
Since the torque in the bending direction can be increased, the vibration amplitude in the torsional direction and the bending direction can be increased.

Further, the drive coil 106 may have a shape as shown in FIG. 3, for example. Further, for example, as shown in FIG. 4, a permanent magnet 104-1 may be further provided facing the side CC ′. According to this configuration, since a force is also generated in a portion along the side CC ′ of the drive coil 106, the torque in the torsional direction can be further increased, and a large vibration amplitude can be obtained.

Further, for example, as shown in FIG.
The sides CD and C'-D 'of 01 may be lengthened. According to this configuration, it is possible to increase both the amplitude in the torsion direction and the amplitude in the bending direction.

Also, for example, as shown in FIG.
A reflective surface 112-1 made of a material such as aluminum may be separately formed on the front surface side of 01 (upper surface in FIG. 6) by, for example, sputtering.

As shown in FIG. 7, for example, one drive coil 106 is connected to the first and second drive coils 404 and 4.
05. In this case, one end of the first drive coil 404 is connected to the contact pad 107-1.
And one end of the second drive coil 405 is connected to the second wiring 108-2 via the contact pad 107-3. Further, the other end of the first drive coil 404 and the other end of the second drive coil 405 are connected to each other from the respective contact pads 107-2 and 107-4 via a wiring 403.

The wiring 403 is insulated from the first and second drive coils 404 and 405 by the first polyimide layer 113 (see FIG. 1). In this case, wiring 4
03 can be formed by photolithography simultaneously with the first and second wirings 108-1 and 108-2 during the semiconductor manufacturing process.

In this configuration, focusing on the first and second drive coils 404 and 405 facing the permanent magnet 104, when an alternating current is applied from the pair of electrodes 109 via the current supply wiring 108, One drive coil 404
When the current I3-1 is flowing through the second drive coil 4
05, the current I3-2 flows and the first drive coil 404
When the current I4-1 flows through the second drive coil 4
At 05, a current I4-2 flows.

In this case, the permanent magnet 104 and the first and second
Interaction between the first and second drive coils 404 and 405 facing the permanent magnet 104 due to the magnetic interaction between the first and second drive coils 404 and 405, the force in the direction perpendicular to the plane of the drawing is always applied. , The first drive coil 404 and the second
Are opposite to each other.

As a result, with the torsion center axis A as the center,
The force acting on the portion of the first drive coil 404 on the C side is greater than the force acting on the portion of the first drive coil 404 and the second drive coil 405 on the D side.
Therefore, the movable plate 101 bends and vibrates simultaneously with the torsional vibration.

Next, an optical deflector according to a second embodiment of the present invention will be described with reference to FIG. In the description of the present embodiment, the same components as those of the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

As shown in FIG. 8, the drive coil 504 applied to the present embodiment has four sides CC ′,
A plurality of turns (four and a half in the present embodiment) are arranged parallel to each other along C′-D ′, D′-D, and DC and along the vicinity of the edge of the movable plate 101.

Further, the movable plate 101 is
The three permanent magnets 501, 502, 503 are fixed in parallel with and opposed to the three sides C′-C, CD, DD ′. Specifically, two permanent magnets 502, 503
Are arranged so as to generate a magnetic field H1 in a direction indicated by an arrow in the drawing with respect to the drive coil 504. Further, the remaining one permanent magnet 501 is arranged such that a magnetic field H2 in a direction indicated by an arrow in the drawing is generated with respect to the drive coil 504.

Next, the operation of this embodiment will be described. When an alternating current is applied to the drive coil 504 and the current I ₁ flows, the drive coil 50
The portion 4 is subjected to a vertical downward force on the paper based on Fleming's left-hand rule, while the portion of the drive coil 504 facing the permanent magnet 503 is subjected to a vertical upward force on the paper. .

On the other hand, when the current I ₂ flows, the portion of the drive coil 504 facing the permanent magnet 502
On the basis of Fleming's left-hand rule, a vertically upward force acts on the paper surface, while a portion of the drive coil 504 facing the permanent magnet 503 exerts a vertically downward force on the paper surface.

At this time, since a couple always acts on the movable plate 101 about the torsion center axis A, the movable plate 101
Vibrates torsionally around the torsion center axis A. In addition, a vertical force acts on the portion of the drive coil 504 facing the permanent magnet 501 on the paper surface in proportion to the alternating current value based on Fleming's left-hand rule.
Vibrates flexibly.

As a result, the movable plate 101 is driven in a two-dimensional direction. According to the present embodiment, by disposing the drive coil 504 near the edge of the movable plate 101, when an alternating current having a constant amplitude is applied, the drive coil 504 acts on the drive coil 504 as compared with other drive coil pattern arrangements. The torque in the twisting direction and the bending direction can be increased. As a result, the torsional vibration amplitude and the flexural vibration amplitude of the movable plate 101 can be increased. In addition,
Other effects are the same as those of the first embodiment, and the description thereof is omitted.

The present invention is not limited to the second embodiment, but can be variously modified. For example, as shown in FIG. 9, even if either the permanent magnet 502 or the permanent magnet 503 is removed, the same operation and effect can be realized. Specifically, the permanent magnet 50
Even when 3 is removed, the movable plate 101 can be torsionally vibrated by the interaction between the permanent magnet 502 and the drive coil 504, and at the same time, the interaction between the permanent magnet 501 and the drive coil 504 Movable plate 1
01 can be flexibly vibrated.

In the configuration shown in FIG. 8, the permanent magnets 502 and 503 may be arranged so that the direction of the magnetic field H1 is reversed. Further, the permanent magnet 501 may be arranged so that the direction of the magnetic field H2 is reversed.

Further, as shown in FIGS. 10A and 10B, a magnetic circuit may be formed by permanent magnets 502 and 503 and a yoke 601 made of a material such as soft iron. In this case, since the strength of the magnetic field H1 can be increased, a force based on Fleming's left-hand rule can be efficiently applied to the drive coil 504.

Next, an optical deflector according to a third embodiment of the present invention will be described with reference to FIG. In the description of the present embodiment, the same components as those of the first and second embodiments are denoted by the same reference numerals, and description thereof will be omitted.

As shown in FIG. 11, the drive coil 504 applied to the present embodiment has four sides CC of the movable plate 101.
, C′-D ′, D′-D, and DC, and are arranged in a plurality of turns (four and a half in the present embodiment) in parallel with each other and along the vicinity of the edge of the movable plate 101. .

The movable member 101 is provided on the support member 110.
, One permanent magnet 701 having a changed magnetic field strength is fixed. Specifically, the permanent magnet 701 is configured such that the average of the intensity of the magnetic field H7 on the C side is stronger than the average of the intensity of the magnetic field H8 on the D side around the torsion center axis A. Have been.

Next, the operation of this embodiment will be described. When an alternating current is applied to the drive coil 504, the permanent magnet 70
A force along the direction perpendicular to the paper surface acts on the portion of the drive coil 504 opposite to 1 based on Fleming's left-hand rule. As a result, the movable plate 101 deflects and vibrates.

At this time, of the portion of the drive coil 504 facing the permanent magnet 701, the force acting on the drive coil 504 on the C side about the torsion center axis A acts on the drive coil 504 on the D side. Greater than force. In this case, since a larger force acts on the portion on the C side of the movable plate 101 than on the portion on the D side, a torque is generated.

As a result, the movable plate 101 vibrates in a two-dimensional direction. Note that the effects of the present embodiment are the same as those of the first and second embodiments, and a description thereof will be omitted.

The present invention is not limited to the third embodiment, but can be variously modified. The permanent magnet 701 has a torsion center axis A as a center,
If the average of the strength of the magnetic field H7 on the C side is stronger than the average of the strength of the magnetic field H8 on the D side, the configuration is not limited to the above-described embodiment. May be.

As shown in FIG. 12, one permanent magnet is combined with a first permanent magnet 702 and a second permanent magnet 703 having a magnetic field strength lower than that of the first permanent magnet 702. You may comprise. Specifically, a first permanent magnet 702 having a strong average of the magnetic field H7 is disposed on the C side around the torsion center axis A, and a second permanent magnet 702 having a weak average of the magnetic field H8 is disposed on the D side. Are disposed. Note that the arrangement of the first and second permanent magnets 702 and 703 may be reversed.

In FIG. 11, the average of the strength of the magnetic field H7 on the C side is configured to be stronger than the average of the strength of the magnetic field H8 on the D side. The average of
The magnetic field H8 on the D side may be configured to be weaker than the average of the strength.

As shown in FIG. 13, for example, a permanent magnet 704 shorter than the length of the side CD of the drive coil 504 is used.
May be arranged closer to either the side CC ′ or the side DD ′ with respect to the side CD. In this case, the permanent magnet 704 is as close as possible to the side CC ′ or the side DD ′.
By moving the movable plate 1
01 can be increased. Further, according to this modification, it is possible to easily adjust the ratio between the torsional amplitude and the deflection amplitude only by changing the length of the permanent magnet 704.

The movable plates 101 applied to the above-described first to third embodiments each have a rectangular shape, but the center of gravity of the movable plate 101 coincides with the extension of the torsion center axis A. 14 and FIG.
It is possible to apply a movable plate 101 having a shape as shown in FIG.

Specifically, FIG. 14 shows a circular movable plate 8.
FIG. 15 shows an isosceles triangular movable plate 901. These movable plates 801 and 901
Since the shape of each of the movable plates 801 and 90 is only line-symmetrical to the torsion center axis A because their shapes are line-symmetrical,
The center of gravity of one can be aligned with the extension of the torsion center axis A. As a result, the movable plate 801,
901 can realize a structure that does not easily generate torsional vibration. It is preferable that the driving coils 802 and 902 are disposed as close to the edges of the movable plates 801 and 901 as possible.

The present specification includes the following inventions. 1. A movable plate capable of forming a reflection surface that reflects light on at least one surface, and a flexible cantilever that can flexibly deform simultaneously with torsional deformation while elastically supporting the movable plate,
A drive coil formed on the movable plate and capable of passing a predetermined current; and a magnetic field generating means capable of applying a predetermined magnetic field to the drive coil. By interacting with the means of generation,
An optical deflector for displacing the movable plate in a torsion direction and a bending direction, wherein a center of gravity of the movable plate substantially coincides with a torsion center axis of the cantilever. (Configuration) The present invention corresponds to all embodiments and modifications.

In the present invention, for example, as shown in FIG. 1, the cantilever corresponds to the torsion / flexure spring 102 supported by the support 111, and the magnetic field generating means corresponds to the movable plate 10
Permanent magnet 1 fixed parallel and opposite to side CD of 1
04 corresponds. (Function and Effect) According to the present invention, the center of gravity of the movable plate and the torsion center axis of the cantilever are made substantially coincident with each other, so that light can be two-dimensionally scanned stably without being affected by external vibration. It is possible to provide a small and inexpensive optical deflector capable of performing the above.

2. The movable plate is formed substantially symmetrically with respect to the torsion center axis of the cantilever, and acts on the drive coil based on an interaction between the energized drive coil and the magnetic field generating means. The drive coil according to claim 1, wherein the drive coil is formed asymmetrically with respect to the torsion center axis so that the magnitude of the force is relatively different in the portions on both sides of the torsion center axis. Optical deflector. (Configuration) The present invention corresponds to the first embodiment (see FIGS. 1 to 3) and modified examples (see FIGS. 4, 5, and 7). According to the present invention, when an alternating current is applied to the drive coil, the magnitude of the force generated in the drive coil based on Fleming's left-hand rule is compared between the two sides of the torsion center axis as a boundary. In this case, the magnitudes of the forces of these two parts are relatively different. At this time, for the movable plate,
Since torques are generated by the forces of relatively different magnitudes acting on both sides of the torsion center axis, the movable plate undergoes torsional vibration. At the same time, the driving coil receives a force in the bending direction based on Fleming's left-hand rule, so that the movable plate bends and vibrates. As a result, the torsional vibration and the flexural vibration occur at the same time.
Drive in the dimension direction.

3. The movable plate and the drive coil,
The direction of the force acting on the drive coil based on the interaction between the energized drive coil and the magnetic field generating means is formed substantially symmetrically with respect to the torsion center axis of the cantilever, The magnetic field generating means includes at least one magnet disposed in parallel with and opposed to the drive coil extending parallel to the torsion center axis so as to be relatively different on both sides of the torsion center axis. 2. The optical deflector according to claim 1, further comprising at least one magnet disposed parallel to and opposite to the drive coil extending perpendicular to the torsion center axis. (Configuration) The present invention corresponds to the second embodiment (see FIG. 8) and a modification (see FIG. 9).

In the present invention, as shown in FIG. 8, for example, the magnetic field generating means comprises three sides C′-C, C
The three permanent magnets 501, 502, and 503 arranged parallel to and opposite to -D and DD 'correspond to this. According to the present invention, a force based on Fleming's left-hand rule acts on the drive coil by the interaction between the magnet and the drive coil arranged in parallel along the torsion center axis, The movable plate undergoes torsional vibration. At the same time, due to the interaction between the magnet and the drive coil arranged perpendicular to the torsion center axis, a force based on Fleming's left-hand rule acts on the drive coil, causing the movable plate to flex and vibrate. .

4. The movable plate and the drive coil,
The drive coil is formed substantially symmetrically with respect to the torsion center axis of the cantilever, and the magnitude of the force acting on the drive coil based on the interaction between the energized drive coil and the magnetic field generating means is reduced. The magnetic field generating means can apply an inhomogeneous magnetic field to the drive coil extending perpendicularly to the torsion center axis so that the magnetic field generation means is relatively different on both sides of the torsion center axis. 2. The optical deflector according to 1 above, further comprising a magnet. (Structure) The third embodiment of the present invention (see FIG. 11)
And modifications (see FIGS. 12, 13, 14, and 15).

In the present invention, for example, as shown in FIG. 11, the magnetic field generating means corresponds to one permanent magnet 701 which is disposed facing the side CD of the movable plate 101 and has a changed magnetic field strength. I do. (Effects) According to the present invention, by applying a non-uniform magnetic field to the drive coil orthogonal to the torsion center axis, the magnitudes of forces acting on the drive coils on both sides with the torsion center axis as a boundary are relatively different. . At this time, for the movable plate,
Since torques are generated by the forces of relatively different magnitudes acting on both sides of the torsion center axis, the movable plate undergoes torsional vibration. At the same time, since the drive coil receives a force in the bending direction, the movable plate bends and vibrates.

5. Wherein the movable plate is congruent with the reflection surface, and the reflection surface is formed on at least one entire surface of the movable plate.
The optical deflector according to any one of the above. (Configuration) The present invention corresponds to all embodiments and modifications. (Effects) According to the present invention, the shape of the movable plate can be reduced to the size required by the reflecting mirror, so that a miniaturized optical deflector can be provided.

6. The optical deflector according to any one of the above items 1 to 5, wherein the magnetic field generating means is fixed to a support member capable of forming a magnetic circuit together with the magnetic field generating means. (Structure) The present invention corresponds to the first embodiment (see FIGS. 1 and 2) and a modification of the second embodiment (see FIG. 10). (Operation and Effect) According to the present invention, the intensity of the magnetic field applied to the drive coil from the magnetic field generating means can be increased, so that the amount of current flowing through the drive coil can be reduced.

[0076]

According to the present invention, it is possible to provide a small and inexpensive optical deflector capable of stably scanning light two-dimensionally without being affected by external vibration.

[Brief description of the drawings]

FIG. 1A is an exploded perspective view showing a configuration of an optical deflector according to a first embodiment of the present invention, and FIG. 1B is a view along the line bb in FIG. Sectional view.

FIG. 2 is a plan view of the optical deflector according to the first embodiment of the present invention.

FIG. 3 is a plan view of an optical deflector according to a modification of the first embodiment.

FIG. 4 is a plan view showing a configuration in which, in the optical deflector according to the modification of the first embodiment, permanent magnets are further provided facing sides CC ′ of the movable plate.

FIG. 5 is a plan view of a portion of a permanent magnet and a movable plate applied to a modification of the first embodiment.

FIG. 6 is a cross-sectional view showing a configuration in which a reflecting surface made of a material such as aluminum is separately formed on the surface side of a movable plate in an optical deflector according to a modification of the first embodiment.

FIG. 7 is a plan view showing a configuration in which first and second drive coils are formed on a movable plate in an optical deflector according to a modification of the first embodiment.

FIG. 8 is a plan view showing a configuration of an optical deflector according to a second embodiment of the present invention.

FIG. 9 is a plan view showing a configuration of an optical deflector according to a modification of the second embodiment.

FIGS. 10A and 10B are diagrams illustrating an optical deflector according to a modification of the second embodiment in which a yoke is additionally provided to configure a magnetic circuit, wherein FIG. 10A is a plan view thereof, and FIG. B in FIG.
Sectional drawing which follows the -b line.

FIG. 11 is a plan view showing a configuration of an optical deflector according to a third embodiment of the present invention.

FIG. 12 is a plan view showing a configuration of an optical deflector according to a modification of the third embodiment.

FIG. 13 is a plan view showing a configuration of an optical deflector according to another modification of the third embodiment.

FIG. 14 is a plan view showing a configuration of an optical deflector to which a circular movable plate is applied in a modification of the present invention.

FIG. 15 is a plan view showing a configuration of an optical deflector to which an isosceles triangular movable plate is applied in a modification of the present invention.

FIG. 16 is a plan view showing a configuration of a conventional optical deflector.

[Explanation of symbols]

 Reference Signs List 101 movable plate 102 torsion / flexion spring 104 permanent magnet 106 drive coil 112 reflection surface A torsion center axis

Claims (3)

[Claims] 1. A movable plate capable of forming a reflection surface for reflecting light on at least one surface, a cantilever that elastically supports the movable plate and is capable of flexibly deforming simultaneously with torsional deformation; A drive coil formed on the plate and capable of applying a predetermined current; and a magnetic field generating means capable of applying a predetermined magnetic field to the drive coil; the energized drive coil and the magnetic field generating means In the optical deflector for displacing the movable plate in the bending direction together with the torsional direction by the interaction with, the center of gravity of the movable plate is substantially coincident with the torsion center axis of the cantilever. Optical deflector. 2. The movable plate is formed substantially symmetrically with respect to a torsion center axis of the cantilever, and the movable plate is formed based on an interaction between the energized drive coil and the magnetic field generating means. The drive coil is formed asymmetrically with respect to the torsion center axis so that the magnitude of the force acting on the drive coil is relatively different on both sides of the torsion center axis. The optical deflector according to claim 1. 3. The movable plate and the drive coil are formed substantially symmetrically with respect to the torsion center axis of the cantilever, and the interaction between the energized drive coil and the magnetic field generating means is performed. The magnetic field generating means is provided on the drive coil extending parallel to the torsion center axis so that the direction of the force acting on the drive coil based on the magnetic field is relatively different on both sides of the torsion center axis. Comprising at least one magnet arranged in parallel and opposed to each other, and at least one magnet arranged in parallel and opposed to the drive coil extending perpendicular to the torsion center axis. The optical deflector according to claim 1, wherein: