JP2009105031A - Electrostatic actuator, microswitch, and electronic equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrostatic actuator, a microswitch, and an electronic equipment capable of stabilizing motions of a membrane. <P>SOLUTION: The electrostatic actuator comprises a suction electrode arranged on a substrate, the membrane arranged facing to the suction electrode, a first elastic beam arranged on the membrane and supporting the membrane, and a pulling section arranged on the membrane and pulling the membrane toward the suction electrode. The pulling section comprises an adsorption section electrostatically absorbed to the suction electrode, and a second elastic beam with its one end connected with the adsorption section. A rigidity of the second elastic beam is smaller than a rigidity of the first elastic beam. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electrostatic actuator, a microswitch, and an electronic device that operate with electrostatic force.

2. Description of the Related Art An electrostatic actuator is known in which an electrostatic force is applied between a stator and a mover constituting an actuator, and the mover is driven by a repulsive force and a suction force. In the field of MEMS (Micro Electro Mechanical Systems) and the like, very small electrostatic actuators, microswitches, and the like have been developed using semiconductor manufacturing technology and the like (see, for example, Patent Document 1).
Here, in the microswitch disclosed in Patent Document 1, the film body is suspended by a plurality of spring elements having different rigidity, and is separated from the film body portion on the spring element side having high rigidity when the switch is turned off. ing.

However, no consideration is given to sucking the film body by the suction electrode with a small force at the start of suction, and there is a possibility that the operation at the start of suction becomes unstable.
Further, when the switch is turned off, the separation time is increased because the film body is separated from the highly rigid spring element side. Operation at the time of separation might become unstable.
JP 2007-35641 A

  The present invention provides an electrostatic actuator, a microswitch, and an electronic device that can stabilize the operation of a film body.

According to one aspect of the present invention, the suction electrode provided on the substrate, the film body provided opposite to the suction electrode, and the first elastic beam provided on the film body and supporting the film body And a traction section provided on the film body and pulling the film body toward the suction electrode, and the traction section is electrostatically sucked toward the suction electrode; and An electrostatic actuator comprising: a second elastic beam having one end connected to the adsorption portion, wherein the rigidity of the second elastic beam is smaller than the rigidity of the first elastic beam. Is provided.
According to another aspect of the present invention, the suction electrode provided on the substrate, the film body provided opposite to the suction electrode, the first film body provided on the film body and supporting the film body. There is provided an electrostatic actuator comprising: one elastic beam; and second suction force limiting means provided on the suction electrode for limiting the suction force with respect to the film body.

  According to another aspect of the present invention, the electrostatic actuator and the at least one pair of input / output electrodes provided on the substrate are provided, and the film body that is electrostatically attracted is provided. The input / output electrodes are connected to each other through a microswitch.

  According to another aspect of the present invention, there is provided an electronic apparatus including the electrostatic actuator described above.

  ADVANTAGE OF THE INVENTION According to this invention, the electrostatic actuator, microswitch, and electronic device which can aim at stabilization of the operation | movement of a film body are provided.

Hereinafter, embodiments of the present invention will be illustrated with reference to the drawings.
FIG. 1 is a schematic view for illustrating an electrostatic actuator according to a first embodiment of the invention.
1A is a schematic plan view, and FIG. 1B is a schematic side view.

  As shown in FIG. 1, the electrostatic actuator 1 includes a substrate 2, suction electrodes 3a and 3b provided on the substrate 2, and an insulating layer 5 provided so as to cover the suction electrodes 3a and 3b. And a plate-like film body 4 disposed immediately above the suction electrodes 3a and 3b.

The substrate 2 is formed of an insulating material such as glass, for example. Note that the surface of the substrate made of a conductive material, a semiconductive material such as silicon (Si), may be covered with an insulating material.
On the substrate 2, the suction electrode 3a and the suction electrode 3b are provided adjacent to each other at a predetermined interval. The suction electrodes 3a and 3b can be formed of a conductive material such as metal, for example. Among the conductive materials, those having a low resistance value are preferable. Examples of such materials include aluminum (Al), gold (Au), silver (Ag), copper (Cu), platinum (Pt), and the like. Examples of these alloys can be given.

  Further, from the viewpoint of generation of the electrostatic force described later, it is preferable that the areas of the suction electrodes 3a and 3b are large. Therefore, it is preferable that the space between the suction electrode 3a and the suction electrode 3b is narrow. 1 illustrates the case where two suction electrodes are provided. However, the present invention is not limited to this. One suction electrode may be provided, or three or more suction electrodes may be provided. Further, the shape is not limited to the illustrated rectangle, and can be changed as appropriate.

The main surfaces of the suction electrodes 3 a and 3 b are covered with an insulating layer 5. The insulating layer 5 can be formed of an insulating material such as silicon oxide (SiO ₂ ), silicon nitride (SiN), or a resin material, for example.

A DC power source (not shown) is connected to the suction electrodes 3a and 3b so that a positive charge or a negative charge can be given to the suction electrodes 3a and 3b. Therefore, the suction electrodes 3a and 3b can suck the film body 4 electrostatically.
When the suction by the suction electrodes 3a and 3b uses Coulomb force or Johnsen-Rahbek force, the film body 4 is made of a conductive material or a semiconductive material. Examples of the conductive material and the semiconductive material include various metal materials, tungsten nitride, silicon, and polysilicon. The Coulomb force can be used by setting the volume resistivity of the material of the insulating layer 5 to 10 ¹⁴ Ωcm or more in the operating temperature range, and if it is 10 ⁸ to 10 ¹¹ Ωcm, the Johnsen-Rahbek force can be increased. It can be used.

  When the suction by the suction electrodes 3a and 3b uses gradient force, the material of the film body 4 can be not only a conductive material and a semiconductive material but also an insulating material. In order to use the gradient force, a non-uniform electric field may be formed on the suction surface by the suction electrodes 3a and 3b. For example, a plurality of suction electrodes may be provided, and a DC power supply (not shown) may be connected so that adjacent suction electrodes have different polarities (positive electrode / negative electrode).

One end of an elastic beam 4a (first elastic beam) is connected to the four corners of the film body 4, and a connecting portion 4b is connected to the other end of the elastic beam 4a. An anchor 6 is disposed on the substrate 2, and a connection portion 4 b is provided on the upper end surface of the anchor 6. That is, the film body 4 is supported by the elastic beam 4a (first elastic beam). The film body 4 is disposed at a position directly above the suction electrodes 3a and 3b via the anchor 6, the connection portion 4b, and the elastic beam 4a.
The substantially rectangular portion at the center of the film body 4 serves as an action portion. The action part is a part that plays a role of transmitting the displacement of the film body 4 (the operation of the electrostatic actuator 1) to the outside, for example, by contacting with an external member.

  When the film body 4 is attracted to the suction electrodes 3 a and 3 b, the elastic beam 4 a is bent, so that the film body 4 is displaced in the normal direction of the substrate 2. When the suction is released, the film body 4 returns to the original position immediately above the suction electrodes 3a and 3b by the action of the elastic beam 4a.

  The connecting positions of the elastic beams 4 a are not limited to the four corners of the film body 4, but may be provided at the peripheral edge of the film body 4. However, if the elastic beams 4 a are connected to the four corners of the film body 4, an operation without distortion can be performed, and thus the horizontal displacement of the film body 4 during operation can be suppressed. Further, the shape of the elastic beam 4a is not limited to the illustrated one, and can be changed as appropriate. However, if the meandering elastic beam 4a illustrated in FIG. 1A is used, the elastic beam 4a having a small spring constant can be arranged in a small area.

  A pulling portion 4c for pulling the film body 4 toward the suction electrodes 3a and 3b is provided on the peripheral portion of the film body 4 immediately above the suction electrodes 3a and 3b. The pulling portion 4c is provided with an elastic beam 4c1 (second elastic beam) and an adsorption portion 4c2 that is attracted by the suction electrodes 3a and 3b. One end of the elastic beam 4c1 is connected to the film body 4, and the other end is connected to the adsorption portion 4c2. The rigidity of the elastic beam 4c1 (second elastic beam) is smaller than that of the elastic beam 4a (first elastic beam). In this case, for example, as illustrated in FIG. 1A, the section modulus of the elastic beam 4c1 may be smaller than the section modulus of the elastic beam 4a by changing the width dimension of the beam. it can. Further, by changing the material of the elastic beam 4c1 and the elastic beam 4a, the rigidity of the elastic beam 4c1 can be made smaller than the rigidity of the elastic beam 4a.

  The width dimension of the adsorption part 4c2 is longer than the width dimension of the elastic beam 4c1, and the area thereof is increased. Thus, if the area of the adsorption part 4c2 is increased, a larger electrostatic force can be generated between the suction electrodes 3a and 3b. The shape of the suction portion 4c2 illustrated in FIG. 1A is a rectangle, but is not limited to this, and can be changed as appropriate. Moreover, the shape of the towing | pulling part 4c is not necessarily limited to what was illustrated, It can change suitably. However, if the planar shape illustrated in FIG. 1A is a traction portion 4c having a spiral shape, the traction portion 4c having a small spring constant can be disposed in a small area.

Moreover, although the arrangement | positioning position of the towing | pulling part 4c illustrated what was provided in the peripheral part (outside) of the film body 4, it is not necessarily limited to this but can change suitably.
FIG. 2 is a schematic partial enlarged view for illustrating the arrangement position of the traction portion.
In addition, the same code | symbol is attached | subjected to the part similar to what was demonstrated in FIG. 1, and the description is abbreviate | omitted suitably. In the present embodiment, the traction part 4 c is provided inside the film body 4. For convenience of explanation, one corner portion is extracted and shown in the figure, but the traction portion 4 c can be provided inside the film body 4 in the other corner portions as well. In the example illustrated in FIG. 2, the pulling portion 4 c is provided on the same side as that illustrated in FIG. 1, but is not limited thereto. The pulling portion 4c only needs to be provided immediately above the suction electrodes 3a and 3b. For example, the pulling portion 4c can be provided on the side where the elastic beam 4a is connected, or a combination thereof. it can. However, if the traction portion 4c is provided outside the film body 4 as illustrated in FIG. 1, the area of the film body 4 can be increased, so that the generated electrostatic force can be increased. it can.

Next, the operation of the electrostatic actuator 1 according to the present embodiment will be described.
When a voltage is applied to the suction electrodes 3a and 3b from a DC power source (not shown), positive or negative charges are applied to the suction electrodes 3a and 3b, and the film body 4 is electrostatically attracted to the suction electrodes 3a and 3b. . At this time, the bending amount (deformation amount) of the film body is determined by the electrostatic force and the elastic force of the film body 4 and the elastic beam 4a, and the bending (deformation) stops when both balance. When application of a voltage from a DC power source (not shown) is stopped, the film body 4 and the elastic beam 4a are restored to their original shape (position) by the elastic force.

Here, in the parallel plate type electrostatic actuator illustrated in FIG. 3, the generated force F can be expressed by the equation (1).

Here, F is a generated force, d is a distance between electrodes, S is an electrode area, ε is a dielectric constant, and V is an applied voltage.

  As can be seen from the equation (1), the generated force F has a characteristic of rapidly decreasing as the distance between the electrodes increases. Therefore, if the suction electrode and the film body (membrane in Patent Document 1) are made substantially parallel as in the technique disclosed in Patent Document 1, an equal force can be applied to the film body at the start of suction. Although there was a problem, it was impossible to apply a large force. In this case, the rigidity of the elastic beam (spring in Patent Document 1) can be lowered so that it can be easily bent even with a small force. However, there is a new problem that the elastic beam is easily damaged. May occur.

  On the other hand, in the electrostatic actuator 1 according to the present embodiment, a traction portion 4c connected to the film body 4 is provided. The rigidity of the elastic beam 4c1 is smaller than the rigidity of the elastic beam 4a. Therefore, at the start of suction, the pulling portion 4c including the elastic beam 4c1 is bent first and is sucked by the suction electrodes 3a and 3b. At this time, since one end of the elastic beam 4c1 is connected to the film body 4, the film body 4 is pulled toward the suction electrodes 3a and 3b, and the inter-electrode distance d (the film body 4 and the suction electrode 3a, 3b) becomes smaller. If the inter-electrode distance d is reduced, a large suction force is generated, so that the film body 4 can be easily sucked. In addition, even after the suction is started, the film body 4 is bent so as to be bent, and thus a portion where a large force is generated gradually expands.

  As a result, the operation of the electrostatic actuator 1 can be greatly stabilized. In addition, since the force required for the operation can be reduced, the applied voltage can be reduced, and the electrostatic actuator can be downsized (the suction electrode can be downsized). Further, it is not necessary to reduce the rigidity of the elastic beam 4a, and the elastic beam 4c1 is a cantilever beam with less restraint, and the acting force can be reduced, so that the breakage can be suppressed. Therefore, the lifetime of the electrostatic actuator 1 can be extended. The force for attracting the pulling portion 4c can be changed as appropriate by adjusting the area of the suction portion 4c2 and the rigidity of the elastic beam 4c1. Further, the suction force can be increased by setting the suction portion 4c2 to protrude from the film body 4 so as to be closer to the suction electrodes 3a and 3b. However, as shown in FIGS. 1 and 2, if the pulling portion 4 c is provided on the same plane as the film body 4, it can be easily processed, so that productivity can be improved.

FIG. 4 is a schematic view for illustrating an electrostatic actuator according to a second embodiment of the invention.
2A is a schematic plan view, and FIG. 2B is a schematic side view. Moreover, the same code | symbol is attached | subjected to the part similar to what was demonstrated in FIG. 1, and the description is abbreviate | omitted suitably.

As shown in FIG. 4, suction force limiting means 7 is provided on the upper surfaces of the suction electrodes 3a and 3b provided in the electrostatic actuator 1a to limit the suction force in the vicinity of the tip of the suction portion 4c2. The suction force limiting means 7 has a protruding shape and is provided so as to protrude from the suction electrodes 3a and 3b. The suction force limiting means 7 is disposed immediately below the suction portion 4c2 of the pulling portion 4c. When the suction portion 4c2 is sucked by the suction electrodes 3a and 3b, the suction force limiting means 7 contacts the vicinity of the tip of the lower surface of the suction portion 4c2. It is possible.
Then, by bringing the vicinity of the tip of the lower surface of the suction portion 4c2 and the suction force limiting means 7 into contact with each other, a gap is provided between the lower surface of the suction portion 4c2 and the suction electrodes 3a and 3b, thereby reducing the suction force. .

  The shape of the suction force limiting means 7 is not particularly limited and can be changed as appropriate. However, as illustrated in FIG. 4, if the contact surface is formed of a curved surface (for example, a hemispherical shape), an unreasonable force is generated when the suction portion 4 c 2 contacts the suction force limiting means 7. Therefore, damage and the like can be suppressed.

  Further, the suction force limiting means 7 illustrated in FIG. 4 has a projecting shape, but may be a concave shape. However, in the projecting shape, the vicinity of the tip of the suction portion 4c2 is further away from the suction electrodes 3a and 3b, so that the suction force in the vicinity of the tip portion described later can be further limited.

Here, the height dimension of the protruding suction force limiting means 7 has a great influence on the force for sucking the suction portion 4c2 to the suction electrodes 3a and 3b. That is, if the height of the projecting suction force limiting means 7 is increased, the force for attracting the suction portion 4c2 to the suction electrodes 3a and 3b can be reduced. Therefore, it is preferable to determine the height dimension of the projecting suction force limiting means 7 in consideration of the separation time (response time) of the suction portion 4c2 described later.
Further, when the suction force limiting means has a concave shape, the depth dimension has a great influence on the force for sucking the suction portion 4c2 to the suction electrodes 3a and 3b. That is, if the depth of the concave suction force limiting means is increased, the force for attracting the suction portion 4c2 to the suction electrodes 3a and 3b can be reduced. Therefore, it is preferable to determine the depth dimension of the concave suction force limiting means in consideration of the separation time (response time) of the adsorption force 4c2 described later.

Next, the operation of the electrostatic actuator 1a according to the present embodiment will be described.
As with the electrostatic actuator 1 illustrated in FIG. 1, when a voltage is applied to the suction electrodes 3a and 3b from a DC power source (not shown), a positive or negative charge is applied to the suction electrodes 3a and 3b. The suction portion 4c2 of 4c is electrostatically attracted to the suction electrodes 3a and 3b. Then, the film body 4 is electrostatically attracted to the suction electrodes 3a and 3b so as to be pulled by the pulling portion 4c. At this time, the bending amount (deformation amount) of the film body is determined by the electrostatic force and the elastic force of the film body 4 and the elastic beam 4a, and the bending (deformation) stops when both balance. When application of a voltage from a DC power source (not shown) is stopped, the film body 4 and the elastic beam 4a are restored to their original shape (position) by the elastic force.

  At this time, since the rigidity of the elastic beam 4c1 is smaller than that of the elastic beam 4a, the film body 4 is first separated from the suction electrodes 3a and 3b, and the suction portion 4c2 is subsequently sucked by the suction part 4c2. Separated from the electrodes 3a, 3b.

  In the present embodiment, the suction force limiting means 7 is brought into contact with the vicinity of the tip of the lower surface of the suction portion 4c2, so that the suction force in the vicinity of the tip can be limited. Here, the tip of the suction portion 4c2 is a portion that is finally separated from the suction electrodes 3a and 3b. Therefore, in addition to the effect of the electrostatic actuator 1 described above, by limiting the suction force in the vicinity of the tip of the suction portion 4c2, the separation of the suction portion 4c2 can be facilitated and the time required for the separation can be shortened. Can do.

FIG. 5 is a schematic perspective view for illustrating the operation of the suction force limiting means.
In addition, it shows that the distance from the attraction | suction electrode 3a, 3b is so long that the color part in a figure is thin.

  As shown in FIG. 5, when the film body 4 is sucked by the suction electrodes 3a and 3b, the elastic beam 4c1 and the suction part 4c2 of the pulling portion 4c are also sucked by the suction electrodes 3a and 3b. However, the vicinity of the tip of the suction portion 4c2 is separated from the suction electrodes 3a and 3b by the action of the protruding suction force limiting means 7. Therefore, since the suction force in this portion can be limited, the separation of the suction portion 4c2 can be facilitated, and the time required for the separation can be shortened.

FIG. 6 is a schematic diagram for illustrating the electrostatic actuator 100 according to the comparative example. FIG. 6A is a schematic plan view of the electrostatic actuator 100, and FIG. 6B is a schematic graph for illustrating the operation of the electrostatic actuator 100.
In FIG. 6B, the vertical axis represents the amount of displacement of the film body, and the horizontal axis represents the drive voltage (voltage applied to the suction electrode). Moreover, the same code | symbol is attached | subjected to the part similar to what was demonstrated in FIG. 1, and the description is abbreviate | omitted suitably.

  As shown in FIG. 6A, a protrusion 104 c is provided on the periphery of the film body 104 provided in the electrostatic actuator 100. The protrusion 104 c has a rectangular outer shape and is provided so as to protrude from the peripheral edge of the film body 104. Moreover, the outer diameter dimension of the protrusion 104c and the outer diameter dimension of the pulling part 4c described above are substantially the same.

Thus, since the electrostatic actuator 100 is not provided with the traction part 4c, a large force is required at the start of suction.
That is, as the drive voltage is increased as shown by the arrow (1) in FIG. 6B, the film body 104 is gradually attracted to the suction electrodes 3a and 3b. Then, as shown by the arrow (2), when the predetermined voltage is reached, the film body 104 is sucked onto the suction electrodes 3a and 3b, but the voltage value at this time becomes high.

  When the drive voltage is lowered as shown by the arrow (3) and reaches a predetermined voltage, the film body 104 is separated from the top of the suction electrodes 3a and 3b as shown by the arrow (4). Even before the drive voltage is set to 0 V (volts), the film body 104 is separated from the suction electrodes 3a and 3b when the elastic force of the elastic beam 4a exceeds the suction force with the suction electrodes 3a and 3b. Is done.

FIG. 7 is a schematic graph for illustrating the operation of the electrostatic actuator 1 illustrated in FIG.
FIG. 8 is a schematic graph for illustrating the operation of the electrostatic actuator 1a illustrated in FIG.
In each figure, the vertical axis represents the amount of displacement of the film body, and the horizontal axis represents the drive voltage (voltage applied to the suction electrode).

In the electrostatic actuator 1 illustrated in FIG. 1, as the drive voltage is increased as indicated by the arrow (5) in FIG. 7, the film body 4 is gradually attracted to the suction electrodes 3a and 3b. As shown by the arrow (6), when the predetermined voltage is reached, the film body 4 is sucked onto the suction electrodes 3a and 3b. As described above, since the electrostatic actuator 1 includes the pulling portion 4c, the pulling portion 4c is first sucked onto the suction electrodes 3a and 3b, and the film body 4 is pulled so as to be pulled. Suction is performed on the suction electrodes 3a and 3b. Therefore, the maximum drive voltage can be reduced by about 15% compared to the case of the electrostatic actuator 100 according to the comparative example illustrated in FIG.
This means that suction can be performed even with a small voltage increase, and it means that the response speed can be improved.

  When the drive voltage is lowered as shown by an arrow (7) and reaches a predetermined voltage, the film body 4 is separated from the suction electrodes 3a and 3b as shown by an arrow (8). In this case, since the suction portion 4c2 of the pulling portion 4c connected to the film body 4 is finally separated from the suction electrodes 3a and 3b, the elastic force of the elastic beam 4c1 is applied to the suction electrode as indicated by an arrow (9). When the suction force with 3a and 3b is exceeded, the film body 4 is separated from the top of the suction electrodes 3a and 3b.

In the electrostatic actuator 1a illustrated in FIG. 4, as the drive voltage is increased as indicated by the arrow (10) in FIG. 8, the film body 4 is gradually attracted to the suction electrodes 3a and 3b. As shown by the arrow (11), when the predetermined voltage is reached, the film body 4 is sucked onto the suction electrodes 3a and 3b. As described above, since the electrostatic actuator 1a is also provided with the pulling portion 4c, the pulling portion 4c is first sucked onto the suction electrodes 3a and 3b, and the film body 4 is pulled so as to be pulled by this. Suction is performed on the suction electrodes 3a and 3b. Therefore, the maximum drive voltage can be reduced by about 15% compared to the case of the electrostatic actuator 100 according to the comparative example illustrated in FIG.
This means that suction can be performed even with a small voltage increase, and it means that the response speed can be improved.

When the drive voltage is lowered as shown by an arrow (12) and reaches a predetermined voltage, the film body 4 is separated from the suction electrodes 3a and 3b as shown by an arrow (13). In this case, the suction portion 4c2 of the pulling portion 4c connected to the film body 4 is finally separated from the suction electrodes 3a and 3b, but the electrostatic actuator 1a is provided with the suction force limiting means 7. Therefore, the film body 4 is separated from the top of the suction electrodes 3a and 3b without the operation shown by the arrow (9) in FIG.
This means that the separation can be performed even with a small voltage drop, and the response speed can be improved.

FIG. 9 is a schematic view for illustrating an electrostatic actuator according to a third embodiment of the invention.
9A is a schematic plan view, and FIG. 9B is a schematic side view. 1 and 4 are denoted by the same reference numerals, and description thereof will be omitted as appropriate.

As shown in FIG. 9, the electrostatic actuator 10 includes a substrate 2, suction electrodes 3 a and 3 b provided on the substrate 2, and an insulating layer 5 provided so as to cover the suction electrodes 3 a and 3 b, And a plate-like film body 4 disposed immediately above the suction electrodes 3a and 3b.
Further, suction force limiting means 7a for limiting the suction force with respect to the film body 4 is provided on the upper surfaces of the suction electrodes 3a and 3b. The suction force limiting means 7a has a protruding shape and is provided so as to protrude from the suction electrodes 3a and 3b. Further, the suction force limiting means 7a is disposed immediately below the film body 4, and can be brought into contact with the lower surface of the film body 4 when the film body 4 is sucked by the suction electrodes 3a and 3b.
Then, by bringing the lower surface of the film body 4 into contact with the suction force limiting means 7a, a gap is provided between the lower surface of the film body 4 and the suction electrodes 3a and 3b so as to reduce the suction force.

  The shape of the suction force limiting means 7a is not particularly limited, and can be changed as appropriate. However, as illustrated in FIG. 9, if the contact surface is formed of a curved surface (for example, hemispherical), an excessive force is applied when the film body 4 contacts the suction force limiting means 7 a. Therefore, damage and the like can be suppressed.

Further, the suction force limiting means 7a illustrated in FIG. 9 has a projecting shape, but may have a concave shape. However, in the projecting shape, the lower surface of the film body 4 is further away from the suction electrodes 3a and 3b, so that the suction force can be more limited.
It should be noted that the suction force limiting means 7a and the suction force limiting means 7 illustrated in FIG.
Further, the number of suction force limiting means 7a, the number of arrangement, the arrangement form, and the like are not limited to those shown in the drawings, and can be changed as appropriate.

Here, the height dimension of the protruding suction force limiting means 7a has a great influence on the force for sucking the film body 4 to the suction electrodes 3a and 3b. That is, if the height of the projecting suction force limiting means 7a is increased, the force for attracting the film body 4 to the suction electrodes 3a and 3b can be reduced. Therefore, it is preferable to determine the height dimension of the protruding suction force limiting means 7a in consideration of the separation time (response time) of the film body 4 to be described later.
Further, when the suction force limiting means has a concave shape, the depth dimension greatly affects the force for sucking the film body 4 to the suction electrodes 3a and 3b. That is, if the depth dimension of the concave suction force limiting means is increased, the force for attracting the film body 4 to the suction electrodes 3a and 3b can be reduced. Therefore, it is preferable to determine the depth dimension of the concave suction force limiting means in consideration of the separation time (response time) of the film body 4 to be described later.

Next, the operation of the electrostatic actuator 10 according to the present embodiment will be described.
Similar to the electrostatic actuator 1 illustrated in FIG. 1, when a voltage is applied to the suction electrodes 3a and 3b from a DC power source (not shown), a positive charge or a negative charge is applied to the suction electrodes 3a and 3b. Therefore, the film body 4 is electrostatically attracted to the suction electrodes 3a and 3b. At this time, the bending amount (deformation amount) of the film body 4 is determined by the electrostatic force and the elastic force of the film body 4 and the elastic beam 4a, and the bending (deformation) stops when both balance. When application of a voltage from a DC power source (not shown) is stopped, the film body 4 and the elastic beam 4a are restored to their original shape (position) by the elastic force.

  In the present embodiment, the suction force limiting means 7a is brought into contact with the lower surface of the film body 4, so that the suction force with respect to the film body 4 can be limited. Therefore, the separation of the film body 4 can be facilitated and the time required for the separation can be shortened. As a result, the response speed can be increased.

FIG. 10 is a schematic diagram for illustrating the electrostatic actuator 110 according to the comparative example. FIG. 10A is a schematic plan view of the electrostatic actuator 110, and FIG. 10B is a schematic graph for illustrating the operation of the electrostatic actuator 110.
In FIG. 10B, the vertical axis represents the amount of displacement of the film body, and the horizontal axis represents the drive voltage (voltage applied to the suction electrode). Moreover, the same code | symbol is attached | subjected to the part similar to what was demonstrated in FIG. 1, and the description is abbreviate | omitted suitably.

As shown in FIG. 10A, the suction electrodes 3a and 3b provided in the electrostatic actuator 110 are not provided with the suction force limiting means 7a. Therefore, a large force is required when the film body 4 is separated from the suction electrodes 3a and 3b.
As the drive voltage is increased as shown by the arrow (14) in FIG. 10B, the film body 4 is gradually attracted to the suction electrodes 3a and 3b. As shown by the arrow (15), when the predetermined voltage is reached, the film body 4 is sucked onto the suction electrodes 3a and 3b, but the voltage value at this time becomes high.

  When the drive voltage is lowered as shown by an arrow (16) and reaches a predetermined voltage, the film body 4 is separated from the suction electrodes 3a and 3b as shown by an arrow (17). Even before the drive voltage is set to 0 V (volts), the film body 4 is separated from the suction electrodes 3a and 3b when the elastic force of the elastic beam 4a exceeds the suction force with the suction electrodes 3a and 3b. Is done.

FIG. 11 is a schematic graph for illustrating the operation of the electrostatic actuator 10 illustrated in FIG. 9.
The vertical axis represents the amount of displacement of the film body, and the horizontal axis represents the drive voltage (voltage applied to the suction electrode).

  In the electrostatic actuator 10 illustrated in FIG. 9, as the drive voltage is increased as indicated by an arrow (18) in FIG. 11, the film body 4 is gradually attracted to the suction electrodes 3a and 3b. As shown by the arrow (19), when a predetermined voltage is reached, the film body 4 is sucked onto the suction electrodes 3a and 3b.

  When the drive voltage is lowered as shown by an arrow (20) and reaches a predetermined voltage, the film body 4 is separated from the suction electrodes 3a and 3b as shown by an arrow (21). In this case, since the lower surface of the film body 4 is brought into contact with the suction force limiting means 7a, the driving is higher than in the case where the suction force limiting means 7a illustrated in FIG. 10B is not provided. Separation can be performed in voltage values. This means that the separation can be performed even with a small voltage drop, and the response speed can be improved.

FIG. 12 is a schematic diagram for illustrating an electrostatic actuator according to a fourth embodiment of the invention.
FIG. 12A is a schematic plan view, and FIG. 12B is a schematic side view. Also, the same parts as those described in FIGS. 1, 4 and 9 are denoted by the same reference numerals, and the description thereof will be omitted as appropriate.

As shown in FIG. 12, the electrostatic actuator 10a is provided with the traction portion 4c illustrated in FIG. 1, the suction force limiting means 7 illustrated in FIG. 4, and the suction force limiting means 7a illustrated in FIG. ing.
Therefore, since the operation and effect of the pulling portion 4c, the suction force limiting means 7 and the suction force limiting means 7a described above can be enjoyed, the operation of the electrostatic actuator 10a can be stabilized and the response speed can be improved. .

FIG. 13 is a schematic diagram for illustrating an electrostatic actuator according to a fifth embodiment of the invention.
FIG. 13A is a schematic plan view, and FIG. 13B is a schematic side view.

  As shown in FIG. 13, the electrostatic actuator 40 includes a substrate 42, suction electrodes 43a and 43b provided on the substrate 42, an insulating layer 45 provided so as to cover the suction electrodes 43a and 43b, And a plate-like film body 44 disposed immediately above the suction electrodes 43a and 43b. The suction electrode 43a and the suction electrode 43b are provided adjacent to each other with a predetermined interval.

  A DC power source (not shown) is connected to the suction electrodes 43a and 43b so that a positive charge or a negative charge can be applied to the suction electrodes 43a and 43b. Therefore, the suction electrodes 43a and 43b can electrostatically attract the film body 44.

  The film body 44 has a substantially circular outer shape, and is provided with groove portions 44d that face each other from the outer periphery toward the center. And two substantially semicircular film bodies 44f are connected via the action part 44e formed by providing the groove part 44d. The action part 44e is a part that plays a role of transmitting the displacement of the film body 44 (the operation of the electrostatic actuator 40) to the outside, for example, by contacting with an external member.

  The film body 44f is divided into an inner peripheral portion 44h1 and an outer peripheral portion 44h2 by grooves 44g formed concentrically, and the inner peripheral portion 44h1 and the outer peripheral portion 44h2 are connected via an elastic beam 44i (second elastic beam). Are connected.

The inner circumferential portion 44h1 is provided with an elastic beam 44a (first elastic beam), a connection portion 44b, and a suction portion 44j. A connecting portion 44 b is provided on the upper end surface of the anchor 46 disposed on the suction electrodes 43 a and 43 b via the insulating layer 45. A central portion of an elastic beam 44c1 described later is provided on the upper end surface of the anchor 46a disposed on the suction electrodes 43a and 43b via the insulating layer 45. That is, the film body 44 is disposed at a position directly above the suction electrodes 43a and 43b via the anchors 46 and 46a.
The connecting portion 44b is connected to the elastic beam 44i on the outer peripheral portion 44h2 through the elastic beam 44a. That is, the elastic beam 44a (first elastic beam) and the elastic beam 44i (second elastic beam) are connected. The elastic beam 44a is also connected to the suction portion 44j via the elastic beam 44k, and the suction portion 44j is connected to the action portion 44e. That is, the film body 44 is supported by the elastic beam 44a (first elastic beam).

  An elastic beam 44i and a pulling portion 44c are provided on the outer peripheral portion 44h2. The pulling portion 44c is provided with an elastic beam 44c1 and an adsorption portion 44c2, and the adsorption portions 44c2 are connected to each other at one end via the elastic beam 44c1. The other end of the adsorption portion 44c2 is connected to the connection portion 44b via the elastic beam 44i and the elastic beam 44a.

By attracting the suction part 44c2 provided in the pulling part 44c to the suction electrodes 43a and 43b, the film body 44 is pulled toward the suction electrodes 43a and 43b. The rigidity of the elastic beam 44c1 and the elastic beam 44i (second elastic beam) is smaller than that of the elastic beam 44a (first elastic beam). Further, the rigidity of the elastic beam 44k connected to the suction portion 44j is also smaller than the rigidity of the elastic beam 44a.
In this case, for example, as illustrated in FIG. 13, the section modulus of the elastic beams 44c1, 44i, and 44k is smaller than the section modulus of the elastic beam 44a by changing the width dimension of the beam. Can do. Also, by changing the material of the elastic beams 44c1, 44i, 44k and the elastic beam 44a, the rigidity of the elastic beams 44c1, 44i, 44k can be made smaller than the rigidity of the elastic beam 44a.

  With the configuration described above, when the film body 44 is attracted to the suction electrodes 43a and 43b, the elastic beams 44a, 44i and 44k are bent, so that the film body 44 is displaced in the normal direction of the substrate 42. . When the suction is released, the film body 44 returns to the original position immediately above the suction electrodes 43a and 43b by the action of the elastic beams 44a, 44i and 44k.

  The arrangement position of the elastic beam 44i is not particularly limited. However, if the elastic beam 44i is provided at a symmetrical position around the connection portion 44b (anchor 46), an operation without distortion can be performed. The horizontal position shift of the film body 44 can be suppressed. Moreover, since the adsorption | suction part 44c2 is connected via the elastic beam 44c1, the position shift of the horizontal direction of the film body 44 at the time of operation | movement can be suppressed more.

  Further, the shapes of the elastic beams 44a, 44c1, 44i, and 44k are not limited to those illustrated, and can be changed as appropriate. However, if the meandering elastic beams 44c1 and 44i illustrated in FIG. 13 are used, the elastic beams having a small spring constant can be disposed in a small area.

  The width dimensions of the suction portions 44c2, 44j are longer than the width dimensions of the elastic beams 44c1, 44i, 44k, and the area thereof is increased. Thus, if the area of the adsorption portions 44c2 and 44j is increased, a larger electrostatic force can be generated between the suction electrodes 43a and 43b. The suction portion 44c2 has a larger area than the suction portion 44j, and is easy to pull. Although the shape of the adsorption | suction part 44c2 illustrated in FIG. 13 is a fan shape, it is not necessarily limited to this, It can change suitably. Further, the shape of the suction portion 44j is not limited to the illustrated one, and can be changed as appropriate. Moreover, although the arrangement | positioning position of the towing | pulling part 44c illustrated what was provided in the outer peripheral part 44h2 of the film body 44, it is not necessarily limited to this but can change suitably.

  Although not shown, suction force limiting means 7 and 7a as illustrated in FIGS. 4 and 9 may be provided. The suction force limiting means can be disposed directly below the suction portion 44c2 of the traction portion 44c. The suction force limiting means 7 and 7a can be the same as those described above, and the description thereof is omitted.

Next, the operation of the electrostatic actuator 40 according to the present embodiment will be illustrated.
FIG. 14 is a schematic perspective view for illustrating the operation of the electrostatic actuator.
In addition, it shows that the distance from the attraction | suction electrodes 43a and 43b is so long that the color part in a figure is light.

  When a voltage is applied to the suction electrodes 43a and 43b from a DC power source (not shown), positive or negative charges are given to the suction electrodes 43a and 43b, and the film body 44 (adsorption portions 44c2 and 44j) is applied to the suction electrodes 43a and 43b. It is attracted electrostatically. At this time, the bending amount (deformation amount) of the film body is determined by the electrostatic force and the elastic forces of the elastic beams 44a, 44i, and 44k, and the bending (deformation) stops when both balance. When application of a voltage from a DC power source (not shown) is stopped, the original shape (position) is restored by the elastic force of the elastic beams 44a, 44i, and 44k.

FIG. 14 shows a state in which the film body 44 (adsorption portions 44c2, 44j) is sucked by the suction electrodes 43a, 43b. That is, when the film body 44 is sucked by the suction electrodes 43a and 43b, the suction portion 44c2, the elastic beam 44i, the suction portion 44j, and the elastic beam 44k are sucked by the suction electrodes 43a and 43b.
In this case, the position in the height direction of the portion supported by the anchors 46 and 46a (the central portion of the connection portion 44b and the elastic beam 44c1) does not change, and is higher than the suction portion 44c2.

  Also in the present embodiment, since the suction portion 44c2 is provided via the pulling portion 44c, that is, the elastic beam 44i having a small rigidity, the elastic beam 44i is more elastic than the elastic beam 44a at the start of suction. Will bend first. Further, the elastic beam 44k having rigidity smaller than that of the elastic beam 44a is also bent first.

Therefore, the suction portions 44c2 and 44j are sucked toward the suction electrodes 43a and 43b, and the inter-electrode distance d (the distance between the film body 44 and the suction electrodes 43a and 43b) is reduced. If the inter-electrode distance d is reduced, a large suction force is generated, so that the suction portions 44c2 and 44j are easily sucked. At this time, since the electrostatic force acting on the suction portion 44c2 having a large area is larger than the electrostatic force acting on the suction portion 44j, the suction portion 44j is pulled by the pulling portion 44c (the suction portion 44c2). Will be sucked.
In addition, even after the suction is started, the elastic beams 44i and 44k are bent so as to bend, so that a portion where a large force is generated gradually expands.

  As a result, the operation of the electrostatic actuator 40 can be greatly stabilized. In addition, since the force required for the operation can be reduced, the applied voltage can be reduced, and the electrostatic actuator can be downsized (the suction electrode can be downsized). Moreover, since it is not necessary to reduce the rigidity of the elastic beam 44a, the damage can be suppressed. Therefore, the life of the electrostatic actuator 40 can be extended. The force for attracting the pulling portion 44c can be changed as appropriate by adjusting the area of the suction portion 44c2 and the rigidity of the elastic beams 44i and 44c1. Further, the suction force can be increased by making the suction portion 44c2 project from the film body 44 so as to be closer to the suction electrodes 43a and 43b. However, as shown in FIG. 13, if the pulling portion 4 c is provided on the same plane as the film body 44, it can be easily processed, so that productivity can be improved.

Further, by providing the suction force limiting means, the suction force at that portion can be limited. In that case, it is possible to easily separate the suction portion 44c2 and the like, and it is possible to shorten the time required for the separation.
In the present embodiment, since the anchor 46a is provided immediately below the elastic beam 44c1, the adsorption portion 44c2 can be separated by using the elastic force of the elastic beam 44c1. Therefore, the separation can be further facilitated, and the time required for the separation can be further shortened.
In addition, since the outer shape of the film body 44 is substantially circular, the size can be reduced.

Next, the microswitch according to the embodiment of the present invention is illustrated.
FIG. 15 is a schematic diagram for illustrating a microswitch according to a sixth embodiment of the present invention.
FIG. 15A is a schematic plan view, and FIG. 15B is a schematic side view.
Moreover, the same code | symbol is attached | subjected to the part similar to what was demonstrated in FIG. 1, and the description is abbreviate | omitted suitably.

  As shown in FIG. 15, the microswitch 20 includes a substrate 2, suction electrodes 3 a and 3 b provided on the substrate 2, an insulating layer 5 provided so as to cover the suction electrodes 3 a and 3 b, and a suction The plate-like film body 4 disposed immediately above the electrodes 3a and 3b, the traction portion 4c provided so as to be connected to the film body 4, and the upper surfaces of the suction electrodes 3a and 3b The suction force limiting means 7 and input / output electrodes 26a and 26b provided between the suction electrodes 3a and 3b and facing each other with a predetermined interval are provided.

  The input / output electrodes 26a and 26b are made of, for example, a conductive material such as metal. Among the conductive materials, those having a low resistance value are preferable. Examples of such materials include aluminum (Al), gold (Au), silver (Ag), copper (Cu), platinum (Pt), and the like. Examples of these alloys can be given. Moreover, if it is made of the same material as the suction electrodes 3a and 3b, it can be formed in the same manufacturing process, so that productivity can be improved.

  From the viewpoint of generation of the electrostatic force described above, it is preferable that the areas of the suction electrodes 3a and 3b are large. Therefore, the space between the suction electrodes 3a and 3b and the input / output electrodes 26a and 26b is preferably narrow. However, if this space is too narrow, a high-frequency signal or the like flowing between the input / output electrodes 26a and 26b may leak to the suction electrodes 3a and 3b. Therefore, the space between the suction electrodes 3a and 3b and the input / output electrodes 26a and 26b is determined according to the application of the microswitch 20 and the like.

Next, the operation of the microswitch 20 according to the present embodiment will be illustrated.
When a voltage is applied to the suction electrodes 3a and 3b from a DC power source (not shown), a positive or negative charge is applied to the suction electrodes 3a and 3b, and the suction portion 4c2 of the traction portion 4c is electrostatically applied to the suction electrodes 3a and 3b. Is aspirated. Then, the film body 4 is electrostatically attracted to the suction electrodes 3a and 3b so as to be pulled by the pulling portion 4c. When application of a voltage from a DC power source (not shown) is stopped, the film body 4 and the elastic beam 4a are restored to their original shape (position) by the elastic force. At this time, since the suction force limiting means 7 is provided near the tip of the lower surface of the suction portion 4c2, the suction force of this portion is limited and the suction portion 4c2 is easily separated.

  In the microswitch 20 according to the present embodiment, when the film body 4 is bent, the film body 4 and the input / output electrodes 26a and 26b come into contact with each other. That is, the input / output electrode 6a and the input / output electrode 6b are electrically connected via the film body 4. Therefore, by bending the film body 4, an electric signal or current can flow between the input / output electrodes 26a and 26b, and by restoring the film body 4, the electric signal or current can be cut off.

  Also in the present embodiment, the film body 4 can be electrostatically attracted to the suction electrodes 3a and 3b so as to be pulled by the pulling portion 4c. Therefore, the film body 4 can be attracted to the suction electrodes 3a and 3b with a small suction force. Further, since the suction force limiting means 7 is provided in the vicinity of the tip of the lower surface of the suction portion 4c2, the suction force in the vicinity of the tip can be limited. Therefore, the separation of the adsorption part 4c2 can be facilitated and the time required for the separation can be shortened.

As a result, the operation of the microswitch 20 can be greatly stabilized. In addition, since the force required for the operation can be reduced, the applied voltage can be reduced, and the microswitch can be downsized (the suction electrode can be downsized).
For convenience of explanation, the case where the suction force limiting means 7 is provided is illustrated, but the present invention is not limited to this. For example, the suction force limiting means 7 is not provided as illustrated in FIG. You can also.
Further, as illustrated in FIG. 12, the suction force limiting means 7 and the suction force limiting means 7a can be provided. Further, as illustrated in FIG. 9, the pulling portion 4 c is not provided, but the suction force limiting means 7 can be provided.

FIG. 16 is a schematic diagram for illustrating a micro switch according to a seventh embodiment of the invention.
16A is a schematic plan view, and FIG. 16B is a schematic side view.
Further, the same parts as those described in FIGS. 13 and 15 are denoted by the same reference numerals, and the description thereof is omitted as appropriate.
The microswitch 20a according to the present embodiment further includes input / output electrodes 26a and 26b described in FIG. 15 in addition to the elements of the electrostatic actuator 40 described in FIG. That is, it further includes input / output electrodes 26a and 26b provided between the suction electrodes 43a and 43b and facing each other with a predetermined interval. Note that the suction force limiting means described with reference to FIGS. 4 and 9 may be further provided.

In the present embodiment, when the film body 44 is bent, the action portion 44e and the input / output electrodes 26a and 26b come into contact with each other. That is, the input / output electrode 6a and the input / output electrode 6b are electrically connected via the action portion 44e. Therefore, by bending the film body 44, an electric signal or current can flow between the input / output electrodes 26a and 26b, and by restoring the film body 44, the electric signal or current can be interrupted.
Since the operation and effect of the electrostatic actuator portion and the material of the input / output electrodes 26a and 26b are the same as those described above, description thereof is omitted.

Next, the micro optical switch 30 according to the embodiment of the present invention will be illustrated.
FIG. 17 is a schematic diagram for illustrating the micro optical switch according to the eighth embodiment of the invention.
In addition, the same code | symbol is attached | subjected to the part similar to what was demonstrated in FIG.1, FIG.4, FIG.9 and FIG. 12, and the description is abbreviate | omitted suitably.

As shown in FIG. 17, the micro optical switch 30 includes a substrate 2, suction electrodes 3a and 3b provided on the substrate 2, and an insulating layer 5 provided so as to cover the suction electrodes 3a and 3b. A plate-like film body 4 disposed immediately above the suction electrodes 3a and 3b, a traction portion 4c provided so as to be connected to the film body 4, and a reflection provided on the surface of the film body 4 Layer 31 is provided. Note that the suction force limiting means 7 and the suction force limiting means 7a may be further provided on the upper surfaces of the suction electrodes 3a and 3b.
Further, the reflective layer 31 does not need to be provided on the entire surface of the film body 4 and can be provided only on a portion that reflects light, which will be described later.
The reflective layer 31 can be formed of a material that easily reflects light, such as Al (aluminum) or Ni (nickel).

Next, the operation of the micro optical switch 30 according to the present embodiment will be described.
When a voltage is applied to the suction electrodes 3a and 3b from a DC power source (not shown), a positive or negative charge is applied to the suction electrodes 3a and 3b, and the suction portion 4c2 of the traction portion 4c is electrostatically applied to the suction electrodes 3a and 3b. Is aspirated. Then, the film body 4 is electrostatically attracted to the suction electrodes 3a and 3b so as to be pulled by the pulling portion 4c. At this time, the bending amount (deformation amount) of the film body is determined by the electrostatic force and the elastic force of the film body 4 and the elastic beam 4a, and the bending (deformation) stops when both balance. When application of a voltage from a DC power source (not shown) is stopped, the film body 4 and the elastic beam 4a are restored to their original shape (position) by the elastic force. At this time, if the suction force limiting means 7 is provided in the vicinity of the tip of the lower surface of the suction portion 4c2, the suction force of this portion can be limited, so that the separation of the suction portion 4c2 can be easily performed. become.
Further, if the suction force limiting means 7a is provided, the film body 4 can be easily separated.
The reflective layer 31 provided on the surface of the film body 4 is also bent and restored together with the film body 4.

In the micro optical switch 30 according to the present embodiment, the optical path of laser light or the like can be changed or controlled by bending and restoring the film body 4. That is, the optical path can be changed or controlled by utilizing the fact that the direction of light reflected by the reflective layer 31 changes when the film body 4 is restored and bent.
Here, the reflective layer 31 included in the micro optical switch 30 can be formed by using a PVD (Physical Vapor Deposition) method, a CVD (Chemical Vapor Deposition) method, or the like.

Also in the present embodiment, the film body 4 can be electrostatically attracted to the suction electrodes 3a and 3b so as to be pulled by the pulling portion 4c. Therefore, the film body 4 can be attracted to the suction electrodes 3a and 3b with a small suction force. Further, if the suction force limiting means 7 is provided in the vicinity of the tip of the lower surface of the suction portion 4c2, the suction force in the vicinity of the tip can be limited. Therefore, the separation of the adsorption part 4c2 can be facilitated, and the time required for the separation can be shortened.
If the suction force limiting means 7a is provided, the film body 4 can be easily separated and the time required for the separation can be shortened.

  According to the present embodiment, the operation of the micro optical switch 30 can be greatly stabilized. In addition, since the force required for the operation can be reduced, the applied voltage can be reduced, and the micro optical switch 30 can be downsized (the suction electrode can be downsized).

FIG. 18 is a schematic diagram for illustrating a micro optical switch system according to a ninth embodiment of the invention.
In addition, the same code | symbol is attached | subjected to the part similar to what was demonstrated in FIG.1, FIG.4, FIG.9, FIG.12 and FIG. 17, and the description is abbreviate | omitted suitably.

  As shown in FIG. 17A, the micro optical switch system 35 includes the above-described micro optical switch 30, light projecting elements 32a and 33a, and light receiving elements 32b and 33b. The light projecting elements 32a and 33a can be, for example, light emitting diodes or laser diodes, and emit light according to external signals. The light receiving elements 32b and 33b can be photoelectric conversion elements that can emit electrical signals in response to light reception, and can be, for example, photodiodes.

  As shown in FIG. 17B, in the micro optical switch system 35 according to the present embodiment, when the film body 4 (reflection layer 31) is bent, the light from the light projecting element 32a is received by the light receiving element 32b. The light projecting element 32a and the light receiving element 32b are arranged as described above. At this time, the light projecting element 33a and the light receiving element 33b are arranged such that light from the light projecting element 33a is not received by the light receiving element 33b.

On the other hand, when the film body 4 (reflection layer 31) is restored, the light projecting element 33a and the light receiving element 33b are arranged such that the light from the light projecting element 33a is received by the light receiving element 33b. At this time, the light projecting element 32a and the light receiving element 32b are arranged such that light from the light projecting element 32a is not received by the light receiving element 32b.
As described above, in the micro optical switch system 35, the light receiving and the light shielding to the light receiving elements 32b and 33b can be switched by switching between the bending and the restoration of the film body 4 (reflection layer 31).

Since other operations of the micro optical switch system 35 are the same as those of the micro optical switch 30, the description thereof is omitted.
Also in the present embodiment, the film body 4 can be electrostatically attracted to the suction electrodes 3a and 3b so as to be pulled by the pulling portion 4c. Therefore, the film body 4 can be attracted to the suction electrodes 3a and 3b with a small suction force. In addition, if the suction force limiting means 7 is provided in the vicinity of the tip of the lower surface of the suction portion 4c2, the suction force in the vicinity of the tip can be limited. Therefore, the separation of the adsorption part 4c2 can be facilitated, and the time required for the separation can be shortened.
If the suction force limiting means 7a is provided, the film body 4 can be easily separated and the time required for the separation can be shortened.

  As a result, the operation of the micro optical switch system 35 can be greatly stabilized. In addition, since the force required for the operation can be reduced, the applied voltage can be reduced, and the micro optical switch system 35 can be downsized (the suction electrode can be downsized).

  For convenience of explanation, FIG. 17 and FIG. 18 exemplify the case where each element of the electrostatic actuator described in FIG. 1 and FIG. 4 is provided, but the present invention is not limited to this. For example, each element of the electrostatic actuator illustrated in FIGS. 9, 12, and 13 may be provided.

The electrostatic actuators 1, 1a, 10, 10a, and 40 according to the present embodiment can be used for various electronic devices.
For example, it can be used for a droplet discharge operation of a droplet discharge head such as an inkjet head, a probe operation of a scanning probe microscope, and other various micromachine operations. The configurations and operations other than the electrostatic actuators 1, 1 a, 10, 10 a, and 40 according to the present embodiment can be applied with known techniques in each case, and thus description thereof is omitted.

  Even in such a case, the operation of each system can be greatly stabilized. In addition, since the force required for the operation can be reduced, the applied voltage can be reduced, and the size of each system (the size of the suction electrode) can be reduced.

The embodiment of the present invention has been illustrated above. However, the present invention is not limited to these descriptions.
As long as the features of the present invention are provided, those skilled in the art appropriately modified the design of the above-described embodiments are also included in the scope of the present invention.
For example, each element included in the electrostatic actuator 1, the electrostatic actuator 1a, the electrostatic actuator 10, the electrostatic actuator 10a, the electrostatic actuator 40, the micro switch 20, the micro switch 20a, the micro optical switch 30, the micro optical switch system 35, and the like. The shape, dimensions, material, arrangement, etc. are not limited to those illustrated, but can be changed as appropriate. Further, a cover for covering these may be provided separately, and the inside of the cover may be decompressed or filled with an inert gas.
Moreover, each element with which each embodiment mentioned above is combined can be combined as much as possible, and what combined these is also included in the scope of the present invention as long as the characteristics of the present invention are included.

It is a mimetic diagram for illustrating the electrostatic actuator concerning a 1st embodiment of the present invention. It is a model partial enlarged view for illustrating the arrangement position of a traction part. FIG. 5 is a schematic perspective view for illustrating the force generated in the parallel plate electrostatic actuator. It is a schematic diagram for illustrating the electrostatic actuator which concerns on the 2nd Embodiment of this invention. It is a model perspective view for illustrating the operation of the suction force limiting means. It is a schematic diagram for illustrating the electrostatic actuator concerning a comparative example. FIG. 2 is a schematic graph for illustrating the operation of the electrostatic actuator illustrated in FIG. 1. FIG. 5 is a schematic graph for illustrating the operation of the electrostatic actuator illustrated in FIG. 4. It is a schematic diagram for illustrating the electrostatic actuator which concerns on the 3rd Embodiment of this invention. It is a schematic diagram for illustrating the electrostatic actuator concerning a comparative example. FIG. 10 is a schematic graph for illustrating the operation of the electrostatic actuator illustrated in FIG. 9. It is a schematic diagram for illustrating the electrostatic actuator which concerns on the 4th Embodiment of this invention. It is a schematic diagram for illustrating the electrostatic actuator which concerns on the 5th Embodiment of this invention. It is a model perspective view for illustrating the operation of an electrostatic actuator. It is a schematic diagram for demonstrating about the microswitch which concerns on the 6th Embodiment of this invention. It is a schematic diagram for demonstrating about the microswitch which concerns on the 7th Embodiment of this invention. It is a schematic diagram for demonstrating about the micro optical switch which concerns on the 8th Embodiment of this invention. It is a schematic diagram for demonstrating about the micro optical switch system which concerns on the 9th Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electrostatic actuator, 1a Electrostatic actuator, 10 Electrostatic actuator, 10a Electrostatic actuator, 2 Substrate, 3a Suction electrode, 3b Suction electrode, 4 Film body, 4a Elastic beam, 4b Connection part, 4c Pulling part, 4c1 Elastic beam 4c2 adsorption part, 5 insulating layer, 6 anchor, 7 suction force limiting means, 20 micro switch, 20a micro switch, 26a input / output electrode, 26b input / output electrode, 30 micro optical switch, 31 reflective layer, 32a light projecting element, 32b Light receiving element, 33a Light projecting element, 33b Light receiving element, 35 Micro optical switch system, 40 Electrostatic actuator

Claims (14)

A suction electrode provided on the substrate;
A film body provided facing the suction electrode;
A first elastic beam provided on the film body and supporting the film body;
A traction section provided on the film body, for pulling the film body toward the suction electrode;
With
The traction portion has a suction portion that is electrostatically attracted toward the suction electrode, and a second elastic beam having one end connected to the suction portion,
The electrostatic actuator characterized in that the rigidity of the second elastic beam is smaller than the rigidity of the first elastic beam.   The electrostatic actuator according to claim 1, wherein the first elastic beam and the second elastic beam are provided at a peripheral portion of the film body.   The electrostatic actuator according to claim 1, wherein the first elastic beam and the second elastic beam are connected to each other.   The electrostatic actuator according to claim 1, wherein the suction electrode includes first suction force limiting means for limiting a suction force with respect to the suction portion.   The electrostatic actuator according to claim 4, wherein the first suction force limiting means protrudes from the suction electrode toward the suction portion.   The electrostatic actuator according to claim 1, wherein the suction electrode includes a second suction force limiting unit that limits a suction force with respect to the film body.   The electrostatic actuator according to claim 6, wherein the second suction force limiting unit protrudes from the suction electrode toward the film body.   The electrostatic actuator according to claim 1, wherein the traction portion has a spiral shape in plan view. A suction electrode provided on the substrate;
A film body provided facing the suction electrode;
A first elastic beam provided on the film body and supporting the film body;
An electrostatic actuator, comprising: a second attraction force limiting unit that is provided on the attraction electrode and limits an attraction force with respect to the film body.   The electrostatic actuator according to claim 9, wherein the second suction force limiting means protrudes from the suction electrode toward the film body. The electrostatic actuator according to any one of claims 1 to 10,
At least one pair of input / output electrodes provided on the substrate;
With
The microswitch, wherein the input / output electrodes are connected to each other through the film body electrostatically attracted. A cover that covers the input / output electrodes and the electrostatic actuator;
The microswitch according to claim 11, wherein the inside of the cover is decompressed. A cover that covers the input / output electrodes and the electrostatic actuator;
The microswitch according to claim 11, wherein the inside of the cover is filled with an inert gas.   An electronic apparatus comprising the electrostatic actuator according to claim 1.