JP2002287075A - Optical deflector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical deflector which is in simple structure, can be driven with a low voltage and increased in light deflection angle, and also can hold a light deflection angle constant. SOLUTION: The optical deflector 10 having a fixed base frame 3 having a cavity part 3', a light reflection part 1 arranged in the cavity part 3', and a couple of support parts 2a and 2b each having one end supported by the light reflection part 1 and the other end held by the fixed base frame 3 is provided with diaphragms 4a and 4b each having one end arranged nearby the lower part of the light reflection part 1 and the other end held by the fixed base frame 3; and one-end sides of the diaphragms 4a and 4b are vibrated at the resonance frequency of the diaphragms 4a and 4b higher than the torsional vibration frequency of the support parts 2a and 2b to hit against the lower part of the light reflection part 1, which can be held obliquely at a specific angle around the support parts 2a and 2b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical deflector, and more particularly, to an optical scanner that uses a laser beam continuously scanned, an optical switch and an optical switch that deflect the laser beam to a predetermined angle to change the direction. The present invention relates to an optical deflector suitable for cross connect and the like.

[0002]

2. Description of the Related Art Scanning devices for optical equipment such as electrophotographic copying machines, laser beam printers, bar code readers, etc., optical deflecting devices for optical disk tracking control devices, and display devices for scanning laser beams and projecting images. For example, an optical deflector is used.

[0003] In general, optical deflectors for mechanically deflecting light include a rotary polygon mirror (polygon mirror) and a vibrating reflecting mirror (galvano mirror). The galvanomirror type is a polygon mirror type. The mechanism can be made smaller than that of, and a prototype of a micromirror using a silicon substrate by applying recent semiconductor process technology has been reported. Further reductions in size, weight, and cost can be expected. .

Conventional examples of such a galvanomirror type optical deflector are shown in FIGS. 8 and 9, respectively.

FIG. 8 is an exploded perspective view showing a first conventional optical deflector. 8, a base 59 is provided with a pair of left and right support portions 51 and 52, and the pair of support portions 5 is provided.
A vibrating body 53 is arranged on 1 and 52. The vibrating body 53 includes an outer frame 54 and an opening 54 of the outer frame 54.
a, and a pair of beams 56, 56 connecting the reflection mirror 55 and the outer frame 54 at an axial position passing through the center of gravity of the reflection mirror 55. Is formed. The left and right ends of the outer frame 54 are fixed on a pair of support parts 51 and 52.

The driving means D has a pair of left and right fixed electrodes 57 and 58 disposed on a base 59, and the pair of fixed electrodes 57 and 58 are located at positions opposed to both left and right ends of the reflection mirror 55. Are located in This pair of fixed electrodes 5
A reflection mirror section 55 is provided as an electrode on the other side of the pair of fixed electrodes 57 and 58. A voltage is selectively applied between one of the pair of fixed electrodes 57 and 58 and the reflection mirror section 55 via a switch SW. It can be applied. Since the reflection mirror 55 is connected to the outer frame 54 via the pair of beams 56, 56, the voltage applied to the reflection mirror 55 may be applied to the outer frame 54.

[0007] The first conventional optical deflector 50A having the above-described configuration.
In the above, when a voltage is applied between one fixed electrode 57 and the reflection mirror portion 55, the left side of the reflection mirror portion 55 with respect to the drawing is attracted by electrostatic force, and the reflection mirror portion 55 is moved to the pair of beam portions 56. , 56, and when a voltage is applied between the other fixed electrode 58 and the reflection mirror portion 55, the right side of the reflection mirror portion 55 is attracted by electrostatic force and the reflection mirror portion is attracted. The portion 55 rotates clockwise about the pair of beam portions 56, 56. Therefore, the reflection mirror 55 vibrates right and left by alternately applying a voltage to the pair of fixed electrodes 57 and 58 by the driving means D. The reflection angle of the light incident on the reflection mirror section 55 is changed by the vibration of the reflection mirror section 55, and the light is deflected by this.

FIG. 9 is an exploded perspective view showing a second conventional optical deflector. In FIG. 9, the same components as those of the first conventional example in the second conventional example are denoted by the same reference numerals in the drawings, and description thereof will be omitted. Only different components will be described.

That is, in the optical deflector 50B of the second conventional example, the driving means D is disposed on a pair of left and right permanent magnets 60 and 61 disposed on the base 59 and on the outer peripheral portion of the reflection mirror section 55. And a driving coil 62, and a driving current is supplied to the driving coil 62 alternately in the forward and reverse directions.

In the optical deflector 50B having the above-described configuration, when a driving current is applied to the driving coil 62 by the driving means D in the alternate direction, the external magnetic field of the pair of permanent magnets 60 and 61 and the driving coil 62 The reflection mirror 55 oscillates around the pair of beams 56, 56 by Lorentz force caused by the current.

[0011]

By the way, the above-mentioned first type is used.
In each of the optical deflectors of the second conventional example, a large optical deflection angle is obtained by causing a vibration which resonates at a mechanical resonance frequency determined by the structures of the mirror reflecting portion and the beam portion in the mirror reflecting portion. Therefore, these optical deflectors
For example, in order to use the optical switch for switching the direction of light to a predetermined position, it is necessary to fix and maintain the light deflection angle at a fixed position. Cannot be used, and it is difficult to obtain a large light deflection angle.

The present invention solves the above-mentioned problems and provides an optical deflector having a simple structure, capable of driving at a low voltage, and capable of increasing the optical deflection angle and keeping the optical deflection angle constant. It is intended to provide.

[0013]

According to another aspect of the present invention, there is provided an optical deflector comprising: a fixed underframe having a hollow portion; a light reflecting portion disposed in the hollow portion; A light deflector supported by the light reflecting portion, the other end of which has a pair of supporting portions held by the fixed underframe, one end of which is disposed close to the lower portion of the light reflecting portion, and the other end of which is disposed. Providing a vibration plate held on the fixed underframe, causing one end of the vibration plate to vibrate at a resonance frequency of the vibration plate higher than the torsional vibration frequency of the pair of support portions to collide with the lower portion of the light reflection portion. An optical deflector characterized in that the light reflecting portion can be held in a state of being inclined by a predetermined angle about the pair of supporting portions.

[0014]

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.

<First Embodiment> FIG. 1 is a perspective view showing a first embodiment of the optical deflector of the present invention. As shown in FIG.
In the light deflector 10, a light reflecting portion 1 having a rectangular shape with a predetermined thickness and reflecting incident light includes a pair of support portions 2.
a, 2b, and these support portions 2a, 2b
Can be used as a rotation axis. That is, the support 2
The rotation axes of a and 2b coincide with each other, and the support portions 2a and 2b are arranged at the position of the center of gravity of the light reflection portion 1. Support part 2
distance 1R from a, 2b to one end 1t of light reflecting portion 1
Is the other end 1t ′ of the light reflecting portion 1 from the supporting portions 2a and 2b.
The distance is the same as 1L. Note that these distances 1R and 1L may be different. The width of the support portions 2a and 2b is 2 W, and is set to be a sufficiently small torsional vibration frequency with respect to the resonance vibration frequency of the diaphragms 4a and 4b described later.

One end of each of the support portions 2a, 2b is held by a fixed underframe 3. The central portion of the fixed underframe 3 is a hollow portion 3 ', which is a concave portion, so that the light reflection plate 1 does not need to rotate around the support portions 2a and 2b without any trouble. . A pair of diaphragms 4a, 4b are formed so that one end is held by the fixed underframe 3 and the other end is a free end, respectively, and tip drive units 5a, 5b are provided on the free end side, respectively. The upper surfaces of the tip drive units 5a and 5b are in contact with the lower surface of the light reflection unit 1 at predetermined positions. When the light reflecting portion 1 is at a horizontal position, the diaphragms 4a,
4b is also horizontal.

Electrodes 6a, 6b are provided on diaphragms 4a, 4b.
For example, drive units 9a and 9b formed by laminating piezoelectric films 7a and 7b and electrodes 8a and 8b respectively are formed. By applying a predetermined voltage between the electrodes 6a, 6b and the electrodes 8a, 8b, the diaphragms 4a, 4b are unimorph (or bimorph) by the driving units 9a, 9b with the end connected to the fixed underframe 3 as a fulcrum. )
Vibration is possible, that is, the tip drive units 5a, 5b
Vibrates in the direction of arrow a. The shapes of the diaphragms 4a and 4b are as follows.
When a unimorph vibration occurs, the vibration frequency is set to be a predetermined resonance frequency.

In the first embodiment, the vibration plate 4 is provided on both sides of the light reflecting portion 1 on the support portions 2a and 2b.
Although a and 4b are arranged, it is needless to say that, for example, one large diaphragm may be provided.

Next, the operation of the optical deflector 10 will be described. FIG. 2 is a sectional view taken along the line AA ′ in FIG. 1 and is for explaining the operation of the optical deflector 10. In addition, also refer to FIG. 1 for the following description.

First, the vibration plates 4a and 4b are
By virtue of a and 9b, they are vibrated in phase at frequencies near the resonance frequency. One end of each of the vibration plates 4a and 4b is
, The leading end driving units 5a and 5b are indicated by arrows a.
Vibrates up and down as shown in the figure. In a state where the vibration resonates at the resonance frequency, even if the voltage applied to the electrodes 6a and 6b and the electrodes 8a and 8b is small, that is, the vibrating plates 4a and 4b vibrate greatly even with a small driving force of the piezoelectric films 7a and 7b. Thus, the distal end driving units 5a and 5b can be largely displaced.

When the vibrating plates 4a and 4b vibrate and the tip driving units 5a and 5b move upward, the light reflecting unit 1 is pushed up by the tip driving units 5a and 5b, and the support units 2a and 2b are pivoted. Then, the end 1t is tilted upward at a maximum angle to a position where the tip end drive units 5a and 5b are maximally displaced. Thereafter, the tip drive units 5a and 5b repeat vertical vibrations in a single vibration motion. When the tip drive units 5a and 5b are displaced downward and separate from the light reflection unit 1, the light reflection unit 1 tends to be horizontal due to the restoring force of the torsion caused by the rotation of the support units 2a and 2b.

When the resonance frequencies of the diaphragms 4a and 4b are low, the light reflecting portion 1 returns to a certain angle and moves upward again while the tip driving portions 5a and 5b move downward and further upward. Since it is repeatedly lifted upward by the displaced tip drive units 5a and 5b, the light reflection unit vibrates and can reflect light within a certain angle range.

On the other hand, when the resonance frequencies of the vibration plates 4a and 4b are set to be sufficiently high, while the speed of restoration by the torsion after rotation of the support portions 2a and 2b is set to be low,
Before the light reflecting portion 1 starts moving to return to its original position, the distal end driving portions 5a and 5b again collide with the light reflecting plate, and this is repeated, so that the light reflecting portion 1 stands still while being inclined at substantially the same angle.

With respect to the tilt angle of the light reflecting portion 1, that is, the angle of light deflection, the maximum displacement amount when the vibration plates 4a and 4b undergo resonance vibration is, for example, in the case of the piezoelectric films 7a and 7b,
Since it is proportional to the magnitude of the applied voltage between the electrodes 6a, 6b and the electrodes 8a, 8b provided on both sides of the piezoelectric films 7a, 7b,
Angle control is possible by voltage control.

Here, when the light reflecting portion 1 is completely stopped, the lowest resonance frequency of the diaphragm required for the return speed of the inclined light reflecting portion 1 must be appropriately selected. The return of the light reflecting portion 1 is preferably slower. For example, when the supporting portions 2a and 2b are connected to the fixed frame 3, the supporting portions 2a and 2b are twisted when the light reflecting portion 1 is inclined. When the force acts, the return speed of the light reflecting portion 1 increases due to the torsion spring component, and the light reflecting portion 1 may not be able to be completely stopped. In such a case, there is a method of reducing the spring component by making the support portions 2a and 2b as thin as possible.

Another method is shown in FIG.
FIG. 3 is a perspective view showing a modification of the first embodiment. As shown in FIG. 3, an optical deflector 10A according to a modification of the first embodiment includes:
In the optical deflector 10 of the first embodiment, the support portions 2a, 2b
In place of the supporting members 2a 'and 2b', and hinges 2a1 and 2b1 are newly provided on the fixed underframe 3. That is, without fixing the support portions 2a 'and 2b' to the fixed underframe 3,
If the hinges 2a1 and 2b1 are used to hold the structure,
There is no spring component, and the return speed can be reduced. Such a structure can be manufactured by a micromachine technology such as a surface micromachine technology or a sacrificial layer etching technology, even if it is as small as a micron. Note that FIG. 3 does not show the driving units 9a and 9b.

Although the case where the driving of the diaphragms 4a and 4b in the optical deflector 10 of the first embodiment is the same has been described above, the diaphragm 4a and the diaphragm 4b may be vibrated at different phases. In this case, when the light reflecting portion 1 is first deflected, the light reflecting portion 1 is lifted by only one of the vibration plates 4a. Next, when the distal end driving unit 5a of the diaphragm 4a is displaced by the maximum upward and returns away from the light reflecting unit 1, the light reflecting unit 1 also attempts to return with a delay.
Is moved upward, so that the light reflecting unit 1 to be returned is stopped and stopped. By repeating such an operation, the deflection angle of the light reflecting portion 1 can be stopped at a fixed position.

<Second Embodiment> FIG. 4 is a perspective view showing a second embodiment of the optical deflector of the present invention. As shown in FIG. 4, in the light deflector 20, the light reflecting portion 11 having a rectangular plate shape having a predetermined thickness and reflecting the incident light includes a pair of support portions 12.
a, 12b, and these support portions 12a,
12b can be tilted with the rotation axis. That is, the rotation axes of the support portions 12a and 12b are coincident, and the support portion 1
Reference numerals 2a and 12b are arranged at the positions of the centers of gravity of the light reflecting portions 11. The distance 11R from the support parts 12a, 12b to one end 11t of the light reflection part 11 is the same as the distance 11L from the support parts 12a, 12b to the other end 11t 'of the light reflection part 11. Note that these distances 11R and 11L may be different. The width of the support parts 12a and 12b is 12W
And diaphragms 14a1, 14b1, 14 described later.
The resonance frequency is set to be sufficiently small with respect to the vibration frequencies a2 and 14b2.

One end of each of the support portions 12a and 12b is held by a fixed underframe 13. The central portion of the fixed underframe 13 is a hollow portion 13 ', which is a concave portion, so that the light reflection plate 11 does not need to rotate around the support portions 12a and 12b without any trouble. . A pair of diaphragms 14
a1 and 14b1 have one end fixed to the supporting portion 13 of the underframe 13.
R, and the other ends are formed as free ends, respectively.
5a1 and 15b1 are formed.
The upper surfaces of 5a1 and 15b1 are in contact with the lower surface of light reflecting portion 11 at predetermined positions. When the light reflecting portion 11 is at a horizontal position, the diaphragms 14a1 and 14b1 are also horizontal.

On the other hand, a pair of diaphragms 14a2 and 14b2 are held at one end by a support portion 13L of the fixed frame 13,
The other ends are formed so as to be free ends, respectively.
2 are formed, and the tip drive units 15a2 and 15b
The lower surface of 2 is in contact with the upper surface of light reflecting portion 11 at a predetermined position. When the light reflecting portion 11 is in a horizontal position, the diaphragm 14a2
14b2 is also horizontal. Supporting part 13L and supporting part 1
3Rs are facing each other.

The electrodes 1 are provided on the diaphragms 15a1 and 15b1.
6a1 and 16b1 and, for example, piezoelectric films 17a1 and 17b1
And drive units 19a1 and 19b1 formed by laminating electrodes 18a1 and 18b1, respectively. Electrodes 16a1, 16b1 and electrodes 18a1, 18
By applying a predetermined voltage between b1, the fixed underframe 1
3 with the end connected to the support portion 13R as a fulcrum.
By 9a1 and 19b1, the diaphragms 14a1 and 14b1 are capable of unimorph (or bimorph) vibration, that is, the tip drive units 15a1 and 15b1 vibrate in the direction of arrow c. The shapes of the vibration plates 14a1 and 14b1 are set such that the vibration frequency becomes a predetermined resonance frequency when unimorph vibration occurs.

On the other hand, on the diaphragms 15a2 and 15b2,
The electrodes 16a2, 16b2 and, for example, the piezoelectric films 17a2, 1
7b2 and drive units 19a2 and 19b2 formed by laminating the electrodes 18a2 and 18b2, respectively. Electrodes 16a2, 16b2 and electrode 18a
When a predetermined voltage is applied between the driving plates 19a2 and 18b2, the vibration plates 14a2 and 14b are driven by the driving portions 19a2 and 19b2 with the end connected to the support portion 13L of the fixed frame 3 as a fulcrum.
b2 is capable of unimorph (or bimorph) vibration, that is, the tip drive units 15a1 and 15b1
Vibrates in the direction of arrow d. Diaphragms 14a2, 14b
The shape of No. 2 is set so that the vibration frequency becomes a predetermined resonance frequency when unimorph vibration occurs.

Next, the operation of the optical deflector 20 will be described. FIG. 5 is a sectional view taken along the line BB ′ in FIG.
This is for explaining the operation of the optical deflector 20 of the embodiment. In addition, also refer to FIG. 4 for the following description.

First, the diaphragms 14a1 and 14b1 are
The driving units 19a1 and 19b1 vibrate in the same phase near the resonance frequency. Since one ends of the vibration plates 14a1 and 14b1 are fixed to the support portion 13R, the distal end driving portions 15a1 and 15b1 vibrate up and down as shown by the arrow c. When the vibration resonates at the resonance frequency, the electrode 16a
1 and 16b1 and the electrodes 18a1 and 18b1 are small, that is, the diaphragms 14a1 and 14b1 can be vibrated greatly even with a small driving force of the piezoelectric films 17a1 and 17b1, and the tip driving units 15a1 and 15b1 can be enlarged. Can be displaced.

On the other hand, the vibration plates 14a2 and 14b2 are vibrated by the driving units 19a2 and 19b2 at the same phase near the resonance frequency, but at the same frequency but different from the phases of the vibration plates 14a1 and 14b1. Diaphragm 14a
Since one end of each of the end portions 2 and 14b2 is fixed to the support portion 13L, the tip end drive portions 15a2 and 15b2 vibrate up and down as shown by the arrow d. When the vibration resonates at the resonance frequency, the electrodes 16a2 and 16b2 and the electrodes 18a2 and 18b2
Is small, that is, the piezoelectric film 17a
Diaphragms 14a2, 14 even with a small driving force of 2, 17b2
b2 can be vibrated greatly, and the tip drive unit 15a
2, 15b2 can be largely displaced.

When the vibrating plates 14a1 and 14b1 vibrate and the leading end driving units 15a1 and 15b1 move upward,
The light reflecting portion 11 is pushed up by the distal end driving portions 15a1 and 15b1, and the end 11t is moved upward at a maximum angle in the direction of arrow b until the distal end driving portions 15a1 and 15b1 are displaced to the maximum with the support portions 12a and 12b as axes. Lean on. Thereafter, the tip drive units 15a1 and 15b1 repeat vertical vibrations in a single vibration motion. When the tip drive units 15a1 and 15b1 are displaced downward and separate from the light reflection unit 11, the light reflection unit 11
Is about to be leveled by the restoring force of the torsion (twist) caused by the rotation of the support portions 12a and 12b.

At this time, the diaphragms 14a2 and 14b2 are
Since the vibrating plates 14a1 and 14b1 are vibrating in different phases, the tip driving units 15a2 and 15b2 move downward, and the light reflecting unit 11 is pushed down by the tip driving units 15a2 and 15b2 to maintain the rotational position. This is repeated alternately. That is, by vibrating the diaphragms 14a2 and 14b2 with a phase different from that of the diaphragms 14a1 and 14b1, when one of the diaphragms 14a1 and 14b1 collides and separates from the light reflecting portion 11 lifted up, the other diaphragm is moved. 1
4a2 and 14b2 collide in the direction of pushing down the light reflecting portion 11 to prevent the light reflecting portion 11 from returning to its original position, and the deflection angle can be kept more accurately, stably and constantly. I have. The operation of the diaphragm is the same as that described in the first embodiment, and a description thereof will not be repeated.

<Third Embodiment> FIG. 6 is a perspective view showing a third embodiment of the optical deflector of the present invention. As shown in FIG. 6, in the optical deflector 30, a light reflecting portion 21 having a rectangular plate shape having a predetermined thickness and reflecting incident light is provided with a pair of support portions 22.
a, 22b, and these support portions 22a,
22b can be tilted with the rotation axis. That is, the rotation axes of the support portions 22a and 22b are coincident, and
2a and 22b are arranged at the position of the center of gravity of the light reflecting portion 21. The distance 21R from the support portions 22a, 22b to one end 21t of the light reflection portion 21 is the same as the distance 21L from the support portions 22a, 22b to the other end 21t 'of the light reflection portion 21. Note that these distances 21R and 21L may be different. The width of the support portions 22a and 22b is 22W
And vibrating plates 24a1, 24b1, 24 described later.
The resonance frequency is set to a sufficiently small resonance frequency with respect to the vibration frequencies a2 and 24b2.

Each of the support portions 22a and 22b has one end held by a fixed underframe 23. The central portion of the fixed underframe 23 is a hollow portion 23 ', which is a concave portion, so that the light reflecting plate 21 does not need to rotate around the supporting portions 22a and 22b without any trouble. . A pair of diaphragms 24
a1 and 24b1 have one end fixed to the support portion 23 of the fixed frame 23.
R, and the other end is formed to be a free end.
5a1 and 25b1 are formed.
The upper surfaces of 5a1 and 25b1 are in contact with the lower surface of light reflecting portion 21 at predetermined positions. When the light reflecting portion 21 is at the horizontal position, the diaphragms 24a1 and 24b1 are also horizontal.

On the other hand, a pair of diaphragms 24a2, 24b2 are provided, and are symmetrical to the pair of diaphragms 24a1, 24b1 with respect to the support portions 22a, 22b.
That is, the pair of diaphragms 24a2 and 24b2 are formed such that one end is held by the support portion 23L of the fixed base frame 23 and the other ends are free ends, respectively. The drive units 25a2 and 25b2 are formed, and the upper surfaces of the tip drive units 25a2 and 25b2 are in contact with the lower surface of the light reflection unit 21 at predetermined positions. When the light reflecting portion 21 is at a horizontal position, the diaphragms 24a2 and 24b2 are also horizontal.

The support 23L and the support 23R face each other. On the diaphragms 25a1, 25b1, electrodes 26a1,
Drive units 29a1 and 29b1 are formed by laminating 26b1, for example, piezoelectric films 27a1 and 27b1, and electrodes 28a1 and 28b1, respectively.
By applying a predetermined voltage between the electrodes 26a1, 26b1 and the electrodes 28a1, 28b1, the drive unit 29a1, with the end connected to the support 23R of the fixed underframe 23 as a fulcrum,
Due to 29b1, the diaphragms 24a1 and 24b1 are capable of unimorph (or bimorph) vibration, that is, the tip drive units 25a1 and 25b1 vibrate in the direction of arrow e. The shapes of the vibration plates 24a1 and 24b1 are set such that the vibration frequency becomes a predetermined resonance frequency when unimorph vibration occurs.

On the other hand, on the diaphragms 25a2 and 25b2,
The electrodes 26a2, 26b2 and, for example, the piezoelectric films 27a2, 2
7b2 and drive units 29a2 and 29b2 formed by laminating the electrodes 28a2 and 28b2, respectively. Electrodes 26a2, 26b2 and electrode 28a
By applying a predetermined voltage between 2, 2b2, the end connected to the support portion 23L of the fixed underframe 23 as a fulcrum,
The diaphragms 24a2, 2 are driven by the driving units 29a2, 29b2.
4b2 is capable of unimorph (or bimorph) vibration, that is, the tip drive units 25a2 and 25b2
Vibrates in the direction of arrow f. Diaphragms 24a2, 24b
The shape of No. 2 is set so that the vibration frequency becomes a predetermined resonance frequency when unimorph vibration occurs.

Next, the operation of the optical deflector 30 will be described. FIG. 7 is a cross-sectional view taken along the line CC 'in FIG. 6, and illustrates the operation of the optical deflector 30 of the third embodiment. In addition, also refer to FIG. 6 for the following description.

First, between the electrodes 26a1, 26b1 and the electrodes 28a1, 28b1, an AC power source 32a, 32b
To apply a predetermined voltage to the diaphragms 24a1, 24b
1 are oscillated in the same phase near the resonance frequency by the drive units 219a1 and 19b1. Diaphragms 24a1, 2
Since one end of 4b1 is fixed to the support portion 23R, the tip drive portions 25a1 and 15b1 vibrate up and down as shown by the arrow e. In a state where the vibration resonates at the resonance frequency, even if the voltage applied to the electrodes 26a1, 26b1 and the electrodes 28a1, 28b1 is small, that is, the piezoelectric films 27a1,
The diaphragms 24a1 and 24b1 can be vibrated greatly with a small driving force of 7b1.
5b1 can be largely displaced.

When the vibrating plates 24a1 and 24b1 vibrate and the tip driving units 25a1 and 25b1 move upward,
The light reflecting portion 21 is pushed up by the tip driving portions 25a1 and 25b1, and the ends 21t are directed upward in the counterclockwise direction of the arrow g until the tip driving portions 25a1 and 25b1 are maximally displaced around the support portions 22a and 22b. Tilt at maximum angle. After that, the tip drive units 25a1 and 25b1 repeat vertical vibrations in a single vibration motion.

When the tip drive units 25a1 and 25b1 are displaced downward and away from the light reflecting unit 21, the light reflecting unit 21
The support portions 22a and 22b try to be level by the restoring force of the torsion (twist) due to the rotation. Diaphragm 24
When the resonance frequencies of a1 and 24b1 are low, the light reflecting unit 21 returns to a certain angle during the period in which the tip driving units 25a1 and 25b1 move downward and further upward, and the tip driving unit that has been displaced upward again. Since it is repeatedly lifted by the portions 25a1 and 25b1, the light reflecting portion 21 can vibrate and reflect light within a certain angle range.

On the other hand, if the resonance frequencies of the vibration plates 24a1 and 24b1 are set to be sufficiently high, while the speed of the restoration by the torsion after rotation of the support portions 22a and 22b is set to be low, the light reflection portion 21 is restored. Before moving back to return to the front end, the tip driving units 25a1 and 25b1
, And this is repeated, so that the light reflecting portion 21 stands still while being inclined at substantially the same angle.

Regarding the inclination angle of the light reflecting portion 21, that is, the angle of the light deflection, the maximum displacement amount when the vibration plates 24a1 and 24b1 undergo resonance vibration is, for example, the piezoelectric films 27a1 and 27a2.
7b1, the electrodes 26a1, 26b1 and the electrodes 28a1, 28b provided on both sides of the piezoelectric films 27a1, 27b1
Since it is proportional to the magnitude of the applied voltage between 1 and 1, the angle can be controlled by voltage control. For example, the range of the light deflection angle is from 0 degree to α degree. Note that α degrees indicates the maximum angle at which the light reflecting portion can be inclined by the vibration of the diaphragm.

Here, another pair of diaphragms 24a2, 24
b2 is pushed down by the light reflection unit 21 via the tip drive units 25a2 and 25b2, and is deformed. The piezo outputs from the piezoelectric films 27a2 and 27b2 are applied to the electrodes 26a2 and 26b2 and the electrodes 28a2 and 28b in accordance with the amount of deformation.
2 can be taken out. The piezo output can be monitored by voltmeters 31a and 31b and used for controlling the light deflection angle.

On the other hand, by vibrating the pair of vibrating plates 24a2 and 24b2 and using the pair of vibrating plates 24a1 and 24b1 for monitoring, the light reflecting part 21 is supported by the supporting parts 22a and 22b.
In the clockwise direction of arrow g around b, the light deflection angle can be changed in the range of 0 degrees to α degrees in the same manner as described above. In the optical deflector 30 of the third embodiment, the angle can be changed within a range of the light deflection angle ± α degrees, and a predetermined angle in the range can be accurately and stably maintained.

Vibration plates 24a1, 24b1, 24a2, 2
Since resonance vibration is used for the vibration of 4b2, a large displacement can be obtained, and the lifted light reflecting portion 21 can also obtain a large deflection angle. Further, the diaphragms 24a1, 24b1, 24a2, and 24b2 are separated from the light reflecting portion 21, and the diaphragms 24a1, 24b1, 24
Since the light reflecting portion 21 is inclined by the pressing force of the a2 and 24b2, if the resonance frequency of the vibration plates 24a1, 24b1, 24a2 and 24b2 is increased, the light reflecting portion 21 will move down from the maximum displaced position even if the light reflecting portion 21 is lowered. 24b1, 24a
Since the light beams 2, 24b2 collide continuously at a high speed, the light reflecting portion 21 can be stopped at a substantially constant deflection angle.

[0052]

As described above, the optical deflector according to the present invention is provided with a diaphragm having one end disposed close to the lower part of the light reflecting portion and the other end held by the fixed underframe. One end is vibrated at a resonance frequency of the vibration plate higher than the torsional vibration frequency of the pair of support portions to collide with the lower portion of the light reflection portion, and the light reflection portion is inclined by a predetermined angle about the pair of support portions. The effect of being able to provide an optical deflector that has a simple structure, can be driven at a low voltage, can increase the optical deflection angle, and can keep the optical deflection angle constant by being able to maintain the state in which the optical deflection angle is maintained. There is.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a first embodiment of an optical deflector of the present invention.

FIG. 2 is a sectional view taken along line A-A 'in FIG.

FIG. 3 is a perspective view showing a modification of the first embodiment.

FIG. 4 is a perspective view showing a second embodiment of the optical deflector of the present invention.

FIG. 5 is a sectional view taken along line B-B 'in FIG.

FIG. 6 is a perspective view showing a third embodiment of the optical deflector of the present invention.

7 is a sectional view taken along the line C-C 'in FIG.

FIG. 8 is an exploded perspective view showing an optical deflector of a first conventional example.

FIG. 9 is an exploded perspective view showing an optical deflector of a second conventional example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Light reflection part, 1t, 1t '... End, 2a, 2b ... Support part, 3 ... Fixed underframe, 3' ... Cavity part, 4a, 4b ... Vibration plate, 5a, 5b ... Tip drive part (one end), 6a, 6b: electrode, 7a, 7b: piezoelectric film, 8a, 8b: electrode, 9a, 9
b: drive unit, 10: light deflector, 11: light reflection unit, 11
t, 11t ': end, 12a, 12b: support, 13: fixed frame, 13': hollow, 13R, 13L: support, 1
4a1, 14a2, 14b1, 14b2 ... vibrating plate, 15
a1, 15a2, 15b1, 15b2... tip drive unit, 1
6a1, 16a2, 16b1, 16b2... Electrodes, 17a
1, 17a2, 17b1, 17b2: piezoelectric film, 18a
1, 18a2, 18b1, 18b2 ... electrodes, 19a1,
19a2, 19b1, 19b2: drive unit, 20: light deflector, 21: light reflection unit, 21t, 21t '... end, 22a,
22b: support portion, 23: fixed underframe, 23 ': hollow portion, 2
3R, 23L ... support parts, 24a1, 24a2, 24b
1, 24b2: vibrating plate, 25a1, 25a2, 25b
1, 25b2... Tip drive unit, 26a1, 26a2, 26
b1, 26b2 ... electrodes, 27a1, 27a2, 27b
1, 27b2: piezoelectric film, 28a1, 28a2, 28b
1, 28b2 ... electrodes, 29a1, 29a2, 29b1,
29b2: drive unit, 30: optical deflector, 31a, 31b ...
Voltmeter, 32a, 32b: Power supply, 50A: Optical deflector, 5
0B: Optical deflector, 51: Supporting part, 52: Indicator, 53 ...
Vibrator, 54 outer frame part, 54a opening, 55 mirror reflection part, 56 beam part, 57 fixed electrode, 58 fixed electrode, 59 base, 60 permanent magnet, 61 permanent magnet,
62 ... Drive coil.

Claims (1)

[Claims] 1. A fixed underframe having a hollow portion, a light reflecting portion disposed in the hollow portion, and a pair of supports having one end supported by the light reflecting portion and the other end held by the fixed underframe. An optical deflector having a diaphragm, one end of which is disposed close to the lower part of the light reflecting portion, and the other end of which is provided on the fixed frame. Vibrating at a resonance frequency of the vibration plate higher than the torsional vibration frequency of the supporting portion and colliding with the lower portion of the light reflecting portion, and in a state where the light reflecting portion is inclined by a predetermined angle around the pair of supporting portions. An optical deflector characterized in that it can be held.