JP2003279864A - Electrostatic actuator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrostatic actuator for holding the displaced state of a needle even when a voltage applied between a movable electrode and a fixed electrode is eliminated and more saving a power consumption. <P>SOLUTION: The electrostatic actuator comprises the movable electrode 2 provided on the needle 21 integrally formed through an elastic supporting body 22 at a fixed part 23 fixed on the surface of a supporting substrate 1, a fixed electrode 3 fixed on the supporting substrate 1 and made to face the movable electrode 2 at an interval so as to be capacitively coupled, a switch plate 4 erected on the needle 21 for passing through light when the needle 21 is at one position and interrupting the light when it is at the other position; and a holding means composed of a fixed engaging part 6 recess-projection connected with a movable engaging part 5 fixed to the supporting substrate 1 and projectingly provided from the needle 1. Corresponding to electrostatic force generated between the movable electrode 2 and the fixed electrode 3, the recess-projection engagement of the movable engaging part 5 and the fixed engaging part 6 is set and released and the needle 21 is displaced. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic actuator operatively displaced by electrostatic force, and more particularly to an electrostatic actuator suitable as an optical control element such as an optical switch.

[0002]

2. Description of the Related Art As an electrostatic actuator, Japanese Unexamined Patent Application Publication No.
What is shown in 0-258702 is shown in FIG. This is an optical control element that constitutes an optical switch, and on a conductive silicon substrate 101 that serves as a fixed electrode,
A square movable electrode plate 102 made of polycrystalline silicon is placed in the air. Further, in the center of each side of the movable electrode plate 102, rectangular cutouts 106, 106, 106,
106 are formed, and these cutouts 106, 106, 10 are formed.
Inward of 6, 6, a support 103 in the form of a folded beam,
103, 103, 103 and fixed parts 105, 105, 1
05 and 105 are formed. In addition, the support 103,
The inner ends of 103, 103, 103 are connected to the movable electrode plate 102, and the outer ends of the fixed parts 105, 105, 105, 105.
Is connected to the silicon substrate 101 via. Also,
A mirror 104 made of polycrystalline silicon is erected at a substantially central portion of the movable electrode plate 102.

Reference numerals 107, 108 and 109 denote optical fibers or optical waveguides, which are a silicon substrate 101 and a movable electrode plate 10.
When a voltage is not applied between 2 and 2, the light incident from the input side 107 is reflected by the mirror 104 and
The direction is changed by 0 ° and enters the output side 108. Further, when a voltage is applied between the silicon substrate 101 and the movable electrode plate 102, an electrostatic force is generated between them and the movable electrode plate 102 is generated.
Are sucked into the silicon substrate 101, and the supports 103, 10
3, 103, 103 are elastically deformed to move the mirror 104 to the silicon substrate 101 side. As a result, the input side 10
The light that has entered from 7 passes straight above the mirror 104 and enters the other output side 109.

Therefore, this electrostatic actuator is
The mirror 104 is displaced by controlling whether or not a voltage is applied between the silicon substrate 101 and the movable electrode plate 102, and the light incident from the input side 107 is output to either the output side 108 or 109. It functions as an optical control element of an optical switch that is incident on one side.

FIG. 5 shows an electrostatic actuator using a comb-shaped movable electrode 207 and a fixed electrode 205 disclosed in JP-A-9-159939.

This is a substrate 201 made of silicon.
The movable part 204 having a mirror-like 208-shaped side surface is provided on the beam 20.
Fixing part 20 fixed to the substrate 201 via 3, 203
2 is elastically supported. In addition, the mirror surface 2 of the movable portion 204
The movable electrode 207 having a comb shape is formed on the side surface opposite to 08.
Then, the fixed electrode 205 is formed so as to face this, thereby forming a capacitor. Then, the movable portion 204 is displaced toward the fixed electrode 205 side by an electrostatic force generated by applying a voltage between the movable electrode 207 and the fixed electrode 205.

[0007]

In these electrostatic actuators, a movable portion (movable electrode plate 102 and movable portion 204) is moved by applying a voltage between the movable electrode and the fixed electrode to generate an electrostatic force. This is for displacing, and the size of the electrostatic actuator can be made small, and further, low power driving is possible.

However, in these devices, when the voltage applied between the movable electrode and the fixed electrode is erased, the electrostatic force does not work, and as a result, the movable portion returns to the initial position. Therefore, there is a problem that a voltage must be constantly applied between the movable electrode and the fixed electrode in order to hold the movable portion in a displaced state.

The present invention has been made in view of the above points, and an object thereof is to maintain the displacement state of the mover even if the voltage applied between the movable electrode and the fixed electrode is erased. To provide an electrostatic actuator that operates.

[0010]

In order to achieve the above object, an electrostatic actuator according to a first aspect of the present invention includes a supporting substrate and a fixing member fixed to the surface of the supporting substrate via an elastic supporting member. The movable electrode provided on the movable element integrally formed with the movable electrode, the fixed electrode fixed on the support substrate and facing the movable electrode at an interval so as to capacitively couple with the movable electrode, and the movable electrode standing on the movable element. Allows light to pass when is in one position,
It consists of a switch plate that blocks light when in the other position, a movable engaging part that projects from the mover, and a fixed engaging part that is fixed to the support substrate. And holding means for holding the concave and convex engagement between the movable engaging portion and the fixed engaging portion of the holding means according to an electrostatic force generated between the movable electrode and the fixed electrode, and displacing the mover. It is characterized by that.

According to a second aspect of the present invention, in the electrostatic actuator of the first aspect, a plurality of at least one of the movable electrode and the fixed electrode is provided.

In the electrostatic actuator according to a third aspect of the present invention, in the structure according to the first aspect, the movable electrode and the fixed electrode are provided with a plurality of convex portions parallel to the support substrate from a predetermined surface of the stem forming the pillar. In addition to the combs provided, the convex portions of the combs are arranged alternately.

According to a fourth aspect of the invention, in the electrostatic actuator according to the third aspect, the ridge angle of the tip of the protrusion of at least one of the electrodes and the ridge angle of the end of the protrusion of the other electrode are chamfered. It is supposed to be done.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

[First Embodiment] FIG. 1 shows a first embodiment of the present invention.
2A and 2B are perspective views showing the electrostatic actuator according to the embodiment of the present invention, and FIG. 1B is an enlarged view of a movable engaging portion and a fixed engaging portion.

The electrostatic actuator of this embodiment has a support substrate 1, a movable electrode 2, a fixed electrode 3, a switch plate 4, a movable engaging portion 5 and a fixed engaging portion 6 as main constituent elements. .

The support substrate 1 has a substantially quadrangular shape in a plan view and is formed of, for example, a semiconductor substrate. A fixed portion 23, a fixed electrode 3, and a fixed engagement portion 6 which will be described later are provided at the predetermined positions via an oxide film 11.

The movable electrode 2 is for generating an electrostatic force Fq between both electrodes by applying a voltage V between the fixed electrodes 3 and 3, and is made of a metal such as nickel. This is formed on a mover 21 having a substantially quadrangular frame body in a plan view, and is formed on a side surface of the mover 21 facing the fixed electrodes 3 and 3.

The mover 21 has a rectangular wave-like support 22 formed by folding back a beam in a direction substantially orthogonal to the projecting direction on a fixed portion 23 which is a substantially rectangular flat plate provided on the support substrate 1. Is integrally formed at its tip via. The mover 21 and the support 22 are not fixed to the support substrate 1, and the support 22 elastically supports the mover 21 so that the mover 21 can swing on the support substrate 1. There is. Furthermore, the mover 21, the support 22, and the fixed portion 2
3 is made of a metal such as nickel like the movable electrode 2.

By applying a voltage between the fixed electrodes 3 and 3 and the movable electrode 2, the fixed electrodes 3 and 3 and the movable electrode 2 are moved.
And an electrostatic force Fq between them and, for example, the movable electrode 2 is made of a metal such as nickel. In addition, the shape is a substantially rectangular flat plate.
This is fixed on the support substrate 1 through the oxide film 11 so as to be substantially parallel to the movable electrode 2 with a predetermined space therebetween, and the movable electrode 2 has a predetermined space in the swing direction. Two are provided separately. Further, a part of the fixed electrodes 3, 3 is arranged so as to be outside the swing range of the mover 21.

The movable engaging portion 5 holds the displaced state of the mover even when the electrostatic force is not applied, by engaging the concave and convex portions with the fixed engaging portion 6 in conjunction with the displacement of the mover 21. For example, like the mover 21, it is made of metal such as nickel. The shape of the beam is a substantially quadrangular beam in plan view, and the beam is provided so as to project from the central portion of the inner side surface of the side of the mover 21 that bears the movable electrode 2 in the plane direction of the support substrate 1. Further, one of the end faces parallel to the protruding direction is in contact with the convex portion 6c of the fixed engaging portion 6.

The fixed engagement portion 6 holds the displacement state of the mover 21 even when the electrostatic force Fq is not applied by engaging the movable engagement portion 5 with each other in a concavo-convex manner. Like the child 21, it is made of a metal such as nickel. This is fixed inside the frame of the mover 21 on the support substrate 1 via the oxide film 11.
The shape is a mountain-shaped flat plate provided with two substantially square recesses 6a and 6b in a plan view on the side facing the movable engaging portion 5. The recesses 6 a and 6 b are opened to the size equal to or larger than the movable engaging portion 5. Also,
The convex portion 6c sandwiched between the concave portions 6a and 6b is formed shorter than the convex portions 6d and 6e on the outside thereof. In addition, the convex portion 6
One of the end faces parallel to the protruding direction of c is in contact with the movable engaging portion 5.

The switch plate 4 controls the optical signal by blocking the light input to the electrostatic actuator or reflecting the light in a predetermined direction. For example, gold (Au).
And the like. The shape is a substantially rectangular flat plate, and is at least as large as the luminous flux of the optical signal to be controlled. In addition, this is erected in parallel with the side of the mover 21 that bears the movable electrode 2.

Next, the operation will be described.

Now, assume that the optical path λ is in the position shown in FIG. An electrostatic actuator is installed so that the switch plate 4 is interposed on the optical path λ of the optical signal in a state where the voltage V is not applied between the movable electrode 2 and the fixed electrodes 3a and 3b. At this time, one end surface of the movable engaging portion 5 and the end surface of the convex portion 6c on the concave portion 6a side are brought into contact with each other, whereby the movable engaging portion 5
The fixed engagement portion 6 and the fixed engagement portion 6 engage with each other. In addition, the mover 21
The restoring force Fr is applied to the fixed member 23 by the support 22 (FIG. 2A).

In this state, when a voltage V is applied between the movable electrode 2 and the fixed electrode 3b in the direction opposite to the displacement of the mover 21, an electrostatic force F is applied between the movable electrode 2 and the fixed electrode 3b.
q occurs. This electrostatic force Fq acts in the direction of pulling the mover 21 toward the fixed electrode 3b side.
Is also applied with a restoring force Fr that causes the support body 22 to return to its original state, and as a result, the movable element 21 receives an electrostatic force Fq.
The combined force Fs acts in the combined direction of the acting direction of F and the acting direction of the restoring force Fr. At this time, since the restoring force Fr is set to be smaller than the electrostatic force Fq, the combined force Fs is slightly directed from the longitudinal direction of the movable electrode 2 to the fixed electrode 3b side, that is, the mover 21 is fixed electrode 3b side. The movable engaging portion 5 can be disengaged from the concave portion 6a and displaced in the longitudinal direction of the movable electrode 2 (FIG. 2B).

Next, when the mover 21 is sufficiently displaced to the fixed electrode 3b side, that is, when the other end face of the movable engaging portion 5 passes through the end face of the convex portion 6c on the concave portion 6b side and is displaced, the movable electrode is moved. 2 and the voltage V applied to the fixed electrode 3b
To cancel. At this time, only the restoring force Fr of the support 22 acts on the mover 21. Since this restoring force Fr has a component that draws the mover 21 toward the fixed portion 23 side, the movable engaging portion 5 is inserted into the concave portion 6b and engages with the fixed engaging portion 6 in a concavo-convex manner so that the end faces abut each other. As a result, the displacement of the mover 21 is maintained. As a result, the switch plate 4 deviates from the optical path λ and allows the optical signal to pass therethrough (FIG. 2C).

According to the electrostatic actuator of the above-described embodiment, the movable engaging portion 5 protruding from the mover 21,
Since the fixed engagement portion 6 that is fixed to the support substrate 1 and engages with the movable engagement portion 5 in a concavo-convex manner is provided, and the concavo-convex engagement is removable by the electrostatic force Fq between the fixed electrodes 3 and 3 and the movable electrode 2,
Even if the voltage V applied between the fixed electrodes 3 and 3 and the movable electrode 2 is erased, the displacement state of the mover 21 can be maintained and power consumption can be reduced.

The fixed electrodes 3 and the movable electrodes 2 are not limited to the numbers shown in this embodiment, and if they are arranged so that an electrostatic force Fq is generated between the electrodes, for example, the fixed electrodes 3 and Two movable electrodes 2 may be provided, and two movable electrodes 2 may be provided instead of one fixed electrode 3.

Further, the shapes of the concave portions 6a and 6b of the movable engaging portion 5 and the fixed engaging portion 6 can be appropriately designed as long as the concave and convex engagement is not released in the state where no voltage is applied. It may have a substantially semicircular shape or a substantially triangular shape.
In this case, the concave and convex engagement between the movable engaging portion 5 and the fixed engaging portion 6 can be smoothly performed.

[Second Embodiment] FIG. 3 shows an electrostatic actuator according to a second embodiment of the present invention.
(A) is the perspective view, (b) is an enlarged view of a fixed electrode and a movable electrode. The electrostatic actuator of this embodiment is different from that of the first embodiment in the shape of the fixed electrode and the movable electrode, and the other constituent elements are substantially the same as those of the first embodiment, and therefore the description thereof is omitted. To do. Further, the same numbers are given to the same members as in the first embodiment.

Similar to the first embodiment, the movable electrodes 7, 7 generate an electrostatic force Fq between both electrodes by applying a voltage V between them and the fixed electrodes 8, 8 facing each other. , And is made of metal such as nickel. This is provided by projecting in the longitudinal direction of the side opposite to one side connected to the support 22 of the mover 21, and its shape is fixed electrodes 8, 8 from the trunk portion 7b protruding in the longitudinal direction.
It is a comb body provided with a plurality of convex portions 7a facing toward. Here, the comb means, for example, a shape obtained by removing one of the side trees supporting the horizontal rails of the ladder. The ridge angle at the tip of the convex portion 7a is chamfered with a flat surface.

The fixed electrodes 8, 8 are movable electrodes 7, 8 facing each other.
By applying a voltage V between the fixed electrode 8 and
The electrostatic force Fq is generated between the movable electrode 7 and the movable electrode 7 and is made of a metal such as nickel, like the movable electrode 7 and 7. Further, the shape thereof is a comb like the movable electrodes 7 and 7, and the convex portion 8a thereof is formed.
Project in the direction of the movable electrodes 7, 7. In addition, this structure is such that the convex portions 7a of the movable electrodes 7 and 7 and the convex portions 8a of the fixed electrodes 8 and 8 are alternately arranged at a predetermined interval with the oxide film 11 interposed therebetween on the support substrate 1. It is fixed. Further, the convex portions 7a and 8a of both electrodes are provided at intervals such that they do not come into contact with each other when the mover 21 is displaced. Further, the ridge angle at the end of the convex portion 8a of this product is chamfered with a flat surface like the tip of the convex portion 7a of the movable electrode 7.

The operation is basically as described in the first embodiment. The only difference is that the displacement direction of the mover 21 is displaced by the substantially longitudinal direction of the movable electrodes 7, 7 as compared with the first embodiment. This is because the electrostatic force Fq generated between the convex portions 7a of the movable electrodes 7 and 7 and the convex portions 8a of the fixed electrodes 8 and 8 is generated in the substantially longitudinal direction of the movable electrodes 7 and 7.

According to the electrostatic actuator of the above-described embodiment, the movable engaging portion 5 projecting from the mover 21,
A fixed engagement portion 6 that is fixed to the support substrate 1 and engages with the movable engagement portion 5 in a concavo-convex manner is provided, and the concavo-convex engagement is removable by the electrostatic force Fq between the fixed electrodes 8 and 8 and the movable electrodes 7 and 7. Therefore, even if the voltage V applied between the fixed electrodes 8 and 8 and the movable electrodes 7 and 7 is erased, the displacement state of the mover 21 can be maintained and power consumption can be reduced. In addition, the movable electrodes 7, 7
By forming the fixed electrodes 8 and 8 in a comb shape, the facing area between the fixed electrodes 8 and 8 and the movable electrodes 7 and 7 increases, and the electrostatic force increases, and at the same time, a part of the convex portions 7a and 8a. Since the ridge angle is chamfered, it is possible to displace in a direction orthogonal to the chamfered portion.

The chamfering of the ridge angles of a part of the convex portions 7a, 8a may be performed on all the ridge angles of both electrodes 7, 7, 8, 8.

[0037]

The electrostatic actuator of the invention according to claim 1 is provided with a movable engaging portion projecting from the mover and a fixed engaging portion fixed to the support substrate, and comprises a movable electrode and a fixed electrode. Since the concave-convex engagement of the movable engaging portion and the fixed engaging portion is set and released according to the electrostatic force generated between the movable element and the mover is displaced, the voltage applied between the movable electrode and the fixed electrode is changed. Even if it is erased, the displacement state of the mover can be held, and the longer the holding time, the more power consumption can be reduced.

In addition to the effect of the first aspect, the electrostatic actuator of the invention according to the second aspect is provided with at least one of the movable electrode and the fixed electrode, so that the displacement of the mover is increased. Can be taken.

In addition to the effect of the first aspect, the electrostatic actuator of the invention according to the third aspect provides the movable electrode and the fixed electrode with a plurality of protrusions parallel to the support substrate from a predetermined surface of the trunk forming the pillar. Since the protrusions are arranged alternately with each other as the comb body provided with the portions, the facing area of the electrodes is increased and the electrostatic force can be made stronger.

In addition to the effect of claim 3, the electrostatic actuator of the invention according to claim 4 has the ridge angle of the tip of the protrusion of at least one electrode and the ridge angle of the end of the protrusion of the other electrode. Since the chamfer is formed, the mover can be displaced obliquely with respect to the longitudinal direction of the electrode, and the concave and convex engagement between the movable engaging portion and the fixed engaging portion can be more easily removed.

[Brief description of drawings]

1A and 1B show an electrostatic actuator according to a first embodiment of the present invention, in which FIG. 1A is a perspective view thereof, and FIG.
FIG. 3 is an enlarged view of a movable engaging portion and a fixed engaging portion.

FIG. 2 is a plan view showing the operation of the electrostatic actuator according to the first embodiment of the present invention.

3A and 3B show an electrostatic actuator according to a second embodiment of the present invention, in which FIG. 3A is a perspective view thereof, and FIG.
FIG. 4 is an enlarged view of a fixed electrode and a movable electrode.

4A and 4B show a conventional electrostatic actuator, in which FIG. 4A is a perspective view thereof, and FIG. 4B is a sectional view taken along the line AA.

FIG. 5 is a perspective view showing another conventional electrostatic actuator.

[Explanation of symbols]

1 Support substrate 11 Oxide film 2 movable electrodes 21 mover 22 Support 23 Fixed part 3 fixed electrode 3a Fixed electrode 3b Fixed electrode 4 switch board 5 Movable engaging part 6 Fixed engagement part 7 movable electrode 7a convex part 7b Executive 8 fixed electrodes 8a convex part

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Atsushi Ogihara             1048, Kadoma, Kadoma-shi, Osaka Matsushita Electric Works Co., Ltd.             Inside the company (72) Inventor Kazukazu Miyajima             1048, Kadoma, Kadoma-shi, Osaka Matsushita Electric Works Co., Ltd.             Inside the company (72) Inventor Katsuhiro Hirata             1048, Kadoma, Kadoma-shi, Osaka Matsushita Electric Works Co., Ltd.             Inside the company F term (reference) 2H041 AA04 AB02 AC06 AZ02 AZ08

Claims (4)

[Claims] 1. A movable electrode provided on a support substrate, a mover integrally formed on a fixed portion fixed to the surface of the support substrate via a support having elasticity, and a movable electrode fixed on the support substrate. Fixed electrodes facing each other at intervals so as to be capacitively coupled; a switch plate standing on the mover to pass light when the mover is in one position and to block light when the mover is in the other position; A movable electrode and a fixed electrode, each of which includes a movable engaging portion projecting from the mover and a fixed engaging portion fixed to the support substrate, and holding means for holding the displacement of the mover by mutually concavo-convex coupling. An electrostatic actuator characterized by releasing the concave and convex engagement between the movable engaging portion and the fixed engaging portion of the holding means and displacing the mover in accordance with an electrostatic force generated between the movable means and the fixed engaging portion. 2. The electrostatic actuator according to claim 1, comprising a plurality of at least one of the movable electrode and the fixed electrode. 3. The movable electrode and the fixed electrode are a comb body in which a plurality of convex portions are provided in parallel with a support substrate from a predetermined surface of a trunk portion forming a pillar body, and the convex portions are alternately arranged. The electrostatic actuator according to claim 1, which has been applied. 4. The electrostatic actuator according to claim 3, wherein at least one of the electrodes has a chamfered ridge angle at the tip of the protrusion and the other electrode has a ridge angle at the end of the protrusion.