JPH08140367A - Electrostatic actuator and its drive method - Google Patents

Abstract

PURPOSE: To increase an operation range as much as possible by eliminating the friction between a movable element and a stator. CONSTITUTION: An electrostatic actuator is provided with a pair of stators 1 and 2 which have body parts 10 and 20 and a plurality of electrodes 11, 12, 21, and 22 formed on the opposing surfaces of the body parts and are arranged oppositely with a specific space and a movable element 3 which advances the space while being alternately attracted by a pair of stators 1 and 2 successively from one edge to other edge while a specific voltage pulse is applied to the electrodes 11, 12, 21, and 22 of the stators 1 and 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic actuator driven by electrostatic force and its driving method.

[0002]

2. Description of the Related Art In recent years, various minute electrostatic actuators for driving a micromachine, which are produced by utilizing a semiconductor manufacturing process, have been announced. These electrostatic actuators are driven by electrostatic force, but none of them have sufficient performance for driving a micromachine. One of the causes and a common problem with these actuators is the problem of friction between the mover and the stator. As a solution to this problem, the mover is mainly supported by an elastic body so that the mover and the stator do not come into contact with each other.The mover is momentarily repelled from the stator by using electrostatic force, and a slight gap is created. A typical method is to reduce the frictional force.

FIG. 17 shows a typical example of an electrostatic actuator using the above method. This electrostatic actuator has fixed electrodes 101, 10 on glass substrates 100a, 100b, respectively.
Stators 104a and 104b on which 2, 103 are formed,
The mover 105 made of silicon and the elastic supporting portions 106a, 1
06b and drives the mover 105 in the direction of the arrow shown in FIG. 17 by the electrostatic force generated when a voltage is applied between the fixed electrodes 101, 102, 103 of the stators 104a and 104b and the mover 105. To do. FIG. 17
The elastic actuators shown in FIG.
If 6b is not provided, the fixed electrodes 101, 102,
When voltages whose phases are shifted by ⅓ each are sequentially applied to 103, the mover 105 moves to the stator 104 a or 10
4b is attracted to the movable element 1 by the frictional force generated at this time.
The operation of 05 becomes difficult. Therefore, in the electrostatic actuator shown in FIG. 17, elastic support portions 106a and 106b are provided to elastically support the mover 105, and the stators 104a and 104b.
The movable member 105 was driven while maintaining a gap between the movable member 105 and the movable member 105.

FIG. 18 shows a typical example of an electrostatic actuator using the above method. This electrostatic actuator has a stator 1 on which electrodes 120a, 120b, 120c are formed.
A movable element 124 including a high resistance element 122 and an insulator 123 is placed on the electrode 21, and the electrodes 120a, 120b, 120c
18 (a) by sequentially applying voltage to
As shown in (b), (c) and (d), the mover 124 is driven. In this case, if the electrodes are simply opposed to each other and a voltage is applied, the electrodes come into contact with each other and are attracted to each other, and it is difficult to operate due to a frictional force. Therefore, in the electrostatic actuator shown in FIG. 18, a method of utilizing the repulsive force of static electricity is adopted. That is, for example, when a positive voltage is applied to the electrode 120a while the mover 124 is attracted to the stator 121, the corresponding portion B of the facing mover 124 is charged negatively by electrostatic induction (FIG. 18).
(See (a) and (b)). If the voltage of the electrode 120a is rapidly switched to negative in this state, the mover 124 and the stator 121 are momentarily slightly separated due to the repulsive force with the negative charge charged in the B section, and the positive charge appearing on the electrode 120b. The mover 124 is moved by the suction force of.

[0005]

As described above, in the conventional electrostatic actuator, how to reduce the friction between the mover and the stator has been an important issue.

However, in the electrostatic actuator using the above method, it is difficult to realize a large operating range because the mover is elastically supported.

Further, in the electrostatic actuator using the above method, the design is not always easy because a relatively complicated physical phenomenon is utilized, and the movable element,
The material properties (dielectric constant, resistivity) of the stator could not always be freely selected. In addition, the driving power source also needed some improvement in terms of switching speed.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an electrostatic actuator which can obtain a large operating range and can smoothly repeat adsorption and separation, and a driving method thereof.

[0009]

A first aspect of an electrostatic actuator according to the first invention comprises a main body and a plurality of electrodes formed on opposite surfaces of the main body, respectively.
A pair of stators, which are arranged to face each other with a predetermined gap, are arranged between the pair of stators, and a predetermined voltage pulse is applied to the electrodes of the stator so that one end of the stator moves to the other end. And a mover advancing through the gap while being alternately attracted to the pair of stators.

In a second aspect of the electrostatic actuator according to the first invention, the first main body portion is connected to a plurality of parallel electrode portions arranged in parallel with a predetermined pitch and one end of these parallel electrode portions is connected. A first stator having first and second electrodes each having a connecting electrode portion for forming the first and second electrodes alternately formed on the first main body portion; A second main body portion, and third and fourth electrodes each having a plurality of parallel electrodes arranged in parallel with a predetermined pitch and connection electrode portions connecting one ends of these parallel electrode portions. A second stator formed by alternately forming the third and fourth electrodes on the second main body, a main body electrode, and a plurality of comb-shaped teeth extending from the main body electrode. A mover having a comb tooth-shaped electrode, and the first and second stators are Are opposed with a clearance arrangement, the mover is characterized by being disposed in the gap.

In a third aspect of the electrostatic actuator according to the first invention, a pair of stators, each having an electrode and an insulating layer covering the electrode, are arranged to face each other with a predetermined gap, the electrode and the pair of stators. A movable element that has an insulating layer that covers the electrodes and that is arranged in the gap between the stators and is movable in this gap; and the insulating layer of the stator and the insulating layer of the movable element are made of the same material. It is formed.

In a fourth aspect of the electrostatic actuator according to the first invention, each has a drive electrode, and a pair of stators arranged with a predetermined gap, and a drive electrode,
And a movable element arranged in a gap between the stators and movable in the gaps. The stator and the movable element are provided with electrodes that form a pair with each drive electrode.

A method of driving an electrostatic actuator according to a second aspect of the present invention has a pair of stators having electrodes and facing each other with a predetermined gap, and a gap between the stators, and a voltage is applied to the electrodes. In the electrostatic actuator including a mover that is alternately attracted to the pair of stators by applying the voltage, the voltage applied to the electrode when the mover is attracted is It is characterized in that the absolute value of the voltage is set to be higher than the absolute value of the subsequent voltage value.

[0014]

According to the first aspect of the electrostatic actuator of the first aspect of the invention configured as described above, when two or more electrodes are formed in one stator, the mover becomes the stator. When adsorbing, instead of adsorbing the mover at one time, it is possible to adsorb one side of the mover first and the other side later. When the mover is attracted in this way, the mover moves toward the attracted side with a slight delay. By repeating this many times at high speed, the mover can move in a large range.

According to the second aspect of the electrostatic actuator of the first invention configured as described above, parallel pattern electrodes of two or more phases are provided on each of the stators on the mover located therebetween. On the other hand, so that the electrodes of each phase appear in order,
In addition, the electrodes of each stator are formed so as to have opposite phases, and voltage is applied to the electrodes of each phase of the stator in sequence so as to correspond to at least one phase of the electrodes of the stator. With respect to the mover having such parallel pattern electrodes, the mover can be repeatedly attracted to the corresponding stator electrodes alternately, thereby realizing a small amount of movement.

According to the third aspect of the electrostatic actuator of the first aspect of the invention configured as described above, the materials of the insulating layers of the electrode parts at the contact points of the stator and the mover are the same. As a result, it is possible to prevent the stator and the mover from being continuously attracted to each other due to electrification due to static electricity, and to realize smooth peeling.

According to the fourth aspect of the electrostatic actuator of the first aspect of the invention, the stator and the mover are provided with electrodes that form a pair with each drive electrode. As a result, it is possible to collect the generated charges on the surfaces of the drive electrodes that face each other as much as possible, and it is possible to utilize the repulsive force as well as the attraction force by static electricity for each drive electrode,
Large output and smooth drive can be realized.

According to the driving method of the electrostatic actuator of the second invention, a high voltage is instantaneously applied immediately after the voltage is applied, and the voltage is reduced when the mover approaches the stator.
As a result, a mover at a distant position can also be attracted by a large electrostatic force, and even if the mover and the stator approach each other, discharge or dielectric breakdown of the insulating film formed on the electrode does not occur. Absent.

[0019]

Embodiments of the present invention will be described below with reference to the drawings.

The construction of the first embodiment of the electrostatic actuator according to the first invention is shown in FIG. The electrostatic actuator of this embodiment has a pair of stators 1 and 2 arranged facing each other.
And a mover 3 and spacers 4a and 4b.
The stator 1 is a material having extremely high electric resistance (eg glass).
Of the plate, and two electrodes 11 and 12 are formed on the surface of the body 10 facing the stator 2. Further, the stator 2 also has a body portion 20 made of a plate made of a material having extremely high electric resistance.
, Two electrodes 21 and 22 are formed on the surface facing the stator 1. The electrode 11 of the stator 1 is formed to extend from one end of the main body 10 to the center, and the electrode 12 is formed to extend from the other end to the center. The electrodes 11 and 12 also extend to the side surfaces of the respective end portions, and the side portions 11b and 12 of these electrodes 11 and 12 extend.
b, conductors 15 and 1 for applying a voltage from the outside, respectively.
6 is connected. Also, the electrodes 21, 22 of the stator 2
Similarly, it is formed so as to extend from each end portion to the central portion, and also extends to the side surface of the corresponding end portion. Conductors 25 and 26 for applying a voltage from the outside are connected to the side portions 21b and 22b, respectively.

A gap is formed between the stators 1 and 2 by interposing spacers 4a and 4b therebetween, and the mover 3 is inserted into this gap. Therefore, the mover 3 is located in the space surrounded by the stators 1 and 2 and the spacers 4a and 4b. A conductor 33 is connected to the mover 3, and the potential of the mover 3 can be adjusted from the outside via the conductor 33.

As shown in FIG. 2, the two electrodes 11 and 12 of the stator 1 are formed by forming conductive films 11a and 12a on a main body made of, for example, a glass wafer.
The structure is such that insulating films 11c and 12c are respectively formed on 2a. Conductive films 11a, 11b, 12a, 12
b may be formed by adhering a metal thin film to the main body portions 10 and 20, or a conductive film may be deposited on the main body portions 10 and 20 by means such as sputtering or vapor deposition, and an etching process or the like may be used. It may be formed by patterning. The insulating films 11c and 12c may be formed by adhering a thin sheet made of a substance having a high electric resistance onto the conductive film, or by a sputtering method or CVD.
It may be formed by depositing a silicon oxide film by using the method. In addition, the conductive wires 15 and 16 are bonded by using a conductive adhesive or joined by means such as wire bonding. The stator 2 has the same structure as the stator 1.

On the other hand, the mover 3 is formed by forming insulating films 3b and 3c on both surfaces of a conductor or resistor 3a as shown in FIG. Therefore, as in the case of the stator, an insulating sheet may be adhered to the thin metal plate, or an insulating film may be formed by sputtering or the like. The conductor 3a may be, for example, silicon or a silicon film on the surface of which a metal film is formed.

When the spacers 4a and 4b are manufactured from a silicon wafer by using a semiconductor manufacturing technique, the silicon wafer is sandwiched between glass wafers which are materials for the stators 1 and 2, and the spacers 4a and 4b are bonded by anodic bonding. 4b can be joined to the stators 1 and 2.

Next, the operation of the electrostatic actuator of this embodiment will be described with reference to FIGS. 3 and 4. FIG. 3 is a process diagram for explaining the order of operations, and FIG. 4 is potentials V ₁₁ , V ₁₂ , applied to the electrodes ₁₁ , ₁₂ , 21, 22 of the stators 1, 2.
Is a Tyne timing chart of V _21, V _22. This operation is an example in which a voltage is sequentially attracted to each electrode 11, 12, 21, 22 and the mover 3 is moved to the left side in FIG. 3 while being attracted alternately between the stators 1 and 2. The electric potential of the mover 3 is always set to 0 (grounded via the conductor 33), and the electric potential of each electrode is sequentially switched to 0 or a predetermined value V. V may be positive or negative. Therefore, for example, if the potential of a certain electrode is V, a potential difference is generated between the electrode and the mover 3,
The mover is attracted to the electrodes by the electrostatic force. 4 in FIG.
It consists of two steps.

First, in step (a), the electrodes 11, 1 are
2 potentials V ₁₁ and V ₁₂ are V, potentials ₂₁ and 22 of electrodes 21 and 22 are V,
V ₂₂ is set to 0 (see FIG. 4), and at this time, the mover 3 is attracted to the stator 1. Next, when the potential V _{11 of the} electrode 11 is switched to 0 and the potential V _{21 of the} electrode 21 is switched to V (time t _{1 in} FIG. 4) from this state, the mover 3 enters the state of step (b). At this time, during the transition from step (a) to step (b), the mover 3 rotates around the point α shown in the figure, and at this time, the rear end of the mover 3 moves to the left by δ in FIG. I understand that Next, the potential V of the electrode 22
_{When 22} is switched to V and the potential V ₁₂ of the electrode 12 is switched to 0 (time t _{2 in} FIG. 4), the process proceeds to step (c). Further, when the potential V _{11 of the} electrode 11 is switched to V and the potential V _{21 of the} electrode 21 is switched to 0 (time t _{3 in} FIG. 4), the state moves to the state of step (d), and at this time, the rear end of the mover 3 is moved. Is again moved to the left side in FIG. 3 by δ. When the potential V ₁₂ of the electrode _{12 is set} to V and the potential V _{22 of the} electrode 22 is set to 0 (see time t _{4 in} FIG. 4), the mover 3 is again attracted to the stator 1 (see step (e)). During the sequence of these four steps, the mover 3 moves to the left in FIG. 3 by 2δ. By repeating this sequence, the mover 3
Moves to the left in FIG. 3, and when the potentials of the electrodes 11, 12, 21, 22 are switched in the order reverse to the above steps, the mover 3 moves to the right in FIG. .

As described above, according to the present embodiment, it is possible to obtain a larger operation range than that of the conventional case, and it is possible to repeat suction and peeling smoothly.

In the above embodiment, the stator 1,
Although an insulating layer is formed on both 2 and the mover 3,
Needless to say, if an insulating layer is formed on either one of the stators 1 and 2 or the mover 3, the same effect as this embodiment can be obtained.

Next, a modification of the first embodiment will be described with reference to FIG. In the first embodiment, the mover 3
Has a relatively high flexural rigidity, that is, the mover 3 has a thickness, or is made of a relatively hard material. In this modification, the mover 3 has a small thickness or is made of a conductive material. This is an example in the case where it is made of a soft material such as natural rubber or a polymer film, has a low bending rigidity, and is easily bent and deformed. In this modification, the electrode 1
Assuming that the pattern of applying the potentials to 1, 12, 21, 22 is the same as that of the first embodiment, the mover 3 is different from that of the first embodiment.
Since the bending rigidity is low, the mover 3 moves between the opposing electrodes while being bent and deformed as shown in FIG. When the mover 3 having a low bending rigidity is used as in this modification, the contact between the stators 1 and 2 and the mover 3 is higher than that in the case where the bending rigidity is high as in the first embodiment. Since the area increases, the electrostatic force between the stator and the mover also increases, and a large propulsive force can be obtained.

Next, a second embodiment of the electrostatic actuator according to the first invention will be described with reference to FIG. The electrostatic actuator of this embodiment uses a mover 3 having a low bending rigidity, and a large number of electrodes are provided on the facing surfaces of the stators 1 and 2 along the traveling direction of the mover 3.

That is, the stator 1 is arranged along the traveling direction of the mover 3.
A large number of electrodes 13 ₁ , ... 13 ₁₀ are provided on the stator 2
Are provided with a large number of electrodes 23 ₁ , ... 23 ₁₀ .
Now, with the electric potential of the mover 3 set to 0, V is applied to the electrodes 13 ₁ , 13 ₂ , 13 ₃ located on the left side of the stator 1 and the electrodes 23 ₅ , ... 23 ₁₀ located on the right side of the stator 2. , The remaining electrodes 13 ₄ , ... 13 ₁₀ and 23 ₁ , ... 23
_Suppose the voltage of ₄ is set to 0. In this state, the mover 3 is in a state drawn by the solid line shown in FIG. From this state, the electrodes on the stator 1 are sequentially applied from the left, and the stator 2
When the upper electrode is grounded to 0 potential in order from the left, the mover is gradually attracted to the stator 1 side from the left side, and after the state shown by the dotted line, the mover moves to the stator 1 side. Move completely. By forming a large number of electrodes on the stators 1 and 2 and sequentially switching the electrodes in this manner, it becomes possible to reliably move the two stators while deforming the mover 3.

In the above description, the example in which the mover 3 on the side of the stator 2 is switched to the side of the stator 1 has been described, but switching from the side of the stator 1 to the side of the stator 2 is completely the same.
By repeating this, the same operation as described in FIG. 5 can be realized.

Next, an embodiment of a method for driving an electrostatic actuator according to the second invention will be described with reference to FIG. The electrostatic actuator used in this embodiment is the actuator of the embodiment shown in FIG.
Voltages V ₁₁ , V ₁₂ , V ₂₁ , and V ₂₂ having a voltage pattern shown in FIG. 7 are applied to the electrodes 12 and 22 of the stator 12 and the stator 12. In the voltage pattern shown in FIG. 7, in the voltage pattern shown in FIG. 4, when the applied voltage rises from 0 to a predetermined value V, a voltage V ₁ higher than the predetermined value V is applied for a time Δt (for example, application of the predetermined value V). 1 ms if the time is 10 msec
ec) is applied and then lowered to a predetermined value V.

The operation when the voltage pattern shown in FIG. 7 is applied to the electrostatic actuator shown in FIG. 1 will be described with reference to FIG. In step (a) of FIG. 3, a voltage of a predetermined value V is applied to the electrodes 11 and 12 of the stator 1,
Since a voltage of 0 is applied to the electrodes 21 and 22 of the stator 2 (between time t _{0 and} t _{1 in} FIG. 7), the mover 3 is attracted to the stator 1, that is, the mover 3. 3 is an electrode 21
It is located away from. Generally, since the electrostatic force is inversely proportional to the square of the distance, even if the voltage of the electrode 21 is switched from 0 to a predetermined value V in the state of step (a) of FIG.
The force of attracting to the electrode 21 side is weak. Therefore, as shown at time t ₁ in FIG. 7, the high voltage V ₁ is applied only immediately after the voltage switching (immediately after the application), and when the mover 3 approaches the electrode 18, the voltage of the predetermined value V is applied to the electrode 18.

In this way, when the movable element adsorbed on one stator is adsorbed on the other stator by switching the voltage applied to the electrode of the other stator, a high voltage is applied only immediately after the switching of the voltage. When the voltage is applied and the mover approaches the electrode of the other stator, the voltage applied to this electrode is reduced to a low voltage to discharge or insulate the insulating film formed on the electrode of the stator or mover. You can prevent destruction.

In the driving method of this embodiment, the electrostatic actuator used has been described using the one shown in FIG. 1. However, in general, a movable element that advances between the stators while being attracted to two stators alternately. It goes without saying that the present invention can also be applied to an electrostatic actuator having a.

Next, a third embodiment of the electrostatic actuator according to the first invention will be described with reference to FIGS. 8 (a) and 8 (b). FIG. 8A shows an electrostatic actuator 40 of this embodiment.
FIG. 8B is a cross-sectional view taken along the line ZZ shown in FIG. The electrostatic actuator 40 of this embodiment is composed of two stators 41 and 42 and a mover 43 between them. Since the stators 41 and 42 have the same structure, the stator 41 will be described and the stator 4 will be described.
The description of 2 is omitted.

The base material of the stator 41 is made of a glass wafer and has four electrodes 41a, 41b, 41c and 41d. For this, for example, a metal thin film is applied by vapor deposition, and an insulating film of a silicon oxide film is formed thereon by sputtering, for example. The stator 41 has a relatively large hole 41i in the center and small holes 41e, 41f, 41g on four sides,
41h is open. These four holes 41e, 41
conductors 45a, 45b, 45c, f, 41g, 41h,
45d is inserted, fixed by a conductive adhesive and electrically connected to the respective electrodes 41a, 41b, 41c, 41d.

On the other hand, the mover 43 (shown by a dotted line in FIG. 8A) is made of, for example, a silicon wafer, a metal film is formed on both surfaces of the silicon wafer, and a silicon oxide film is formed as an insulating film on the metal film. It A small hole 43h is formed in the center of the mover 43, and an insulating film is not formed around it. By passing a conductive shaft (not shown) through this hole, the movement of the mover 43 can be taken out, and the potential of the mover 43 can be adjusted from the outside through the shaft (this will be described later). ).

Further, the spacers 44 are provided on four sides to keep the gap between the stators 40 and 41 and to serve as a guide so that the mover 43 is not outside the actuator 40. If the spacer 44 is made of silicon, it can be manufactured together with the mover 43 from a single silicon wafer, and anodic bonding can be used to join the stators 41 and 42.

Next, the operation will be described. This actuator 40 has a total of eight electrodes 41a, ... 41d, 42a, ... 42d with two stators 41, 42. If two actuators 41a, ... 41d, 42a ,. Can be operated in the same manner as. That is, the stator 4
1 electrodes 41a and 41d, 41b and 41c, stator 42
Electrodes 42a and 42d, 42b and 42c of the first
When viewed as one electrode in the above embodiment, it can be operated in the X direction. Similarly, the electrodes 41a and 41a
b, 41c and 41d, 42a and 42b, 42c and 42d
When each is regarded as one electrode in the first embodiment, the mover can be operated in the Y direction. In this way, the actuator 40 of this embodiment is a two-degree-of-freedom actuator that can be freely driven in the X and Y directions.

Next, the actuator 4 of the embodiment shown in FIG.
An example in which 0 is applied to the pan-tilt pan head will be described with reference to FIG. The shaft 50 is passed through a hole 43h provided in the mover 43 of the actuator 40. The actuator 40 is supported by a support member 51 having a recess at the center. A pivot bearing 51a is formed in the center of the recess of the support member 51. Further, the pivot 50a is provided at one end of the shaft 50 on the support member 51 side.
Is formed, the pivot 50a is supported by the pivot bearing 51a so that the shaft 50 can swing. Further, the shaft diameter of the portion 50b of the shaft 50 on the support member 51 side is larger than the diameter of the hole 43h of the mover 43,
The shaft 50 prevents the shaft 40 from coming out on the side opposite to the support member 51 of the actuator 40. Then, a pan-tilt movable portion is attached to an end portion of the shaft 50 opposite to the pivot 50a.

In the pan-tilt pan head constructed as described above, the actuator 40 is driven and the mover 43 is moved as shown in FIG.
When operated in the X direction shown in (a), the pan / tilt movable unit 5 is moved.
2 makes a swinging motion in the ψ _Y direction, and the mover 43 moves in the _Y direction.
When the pan / tilt movable portion 52 is moved in the direction, the pan / tilt movable portion 52 makes a swinging motion in the ψ _X direction.

Next, a fourth embodiment of the electrostatic actuator according to the first invention will be described with reference to FIGS. FIG. 10 is an exploded view for explaining the configuration of this embodiment. The electrostatic actuator of this embodiment includes two stators 1 and 2, a mover 3, and spacers 4a and 4b for holding a gap between the two stators 1 and 2.

The stator 1 is formed by providing two electrodes 13 and 14 on the surface of the main body 10 made of an insulating material or a material having an extremely high electric resistance, the surface facing the stator 2. Electrode 13
Is composed of a plurality of parallel electrode portions 13a arranged in parallel with a predetermined pitch P, and a connecting electrode portion 13b connecting one ends of these parallel electrode portions 13a. Similarly, the electrode 14 also has a plurality of parallel electrode portions 14a arranged in parallel with a predetermined pitch P, and these parallel electrode portions 14a.
It is composed of a connecting electrode portion 14b for connecting one end of a. The wiring width of the connecting electrode portions 13b and 14b is formed to be wider than the wiring width of the parallel electrode portions 13a and 14a. The electrodes 13 and 14 are arranged so as to be staggered from each other by 1/2 pitch. Conductive wires 17, 1 connected to an external power source are connected to the connecting electrode portions 13b, 14b.
8 are connected respectively.

The stator 2, like the stator 1, is made of an insulating material or a material having an extremely high electric resistance.
The two electrodes 23 and 24 are provided on the surface of the stator facing the stator 1. The electrode 23 is composed of a plurality of parallel electrode portions 23a arranged in parallel with a pitch P and a connecting electrode portion 23b connecting one end of these parallel electrode portions 23a, and the electrode 24 is arranged in parallel with a pitch P. A plurality of parallel electrode portions 24a, and a connecting electrode portion 24b for connecting one end of these parallel electrode portions 24a.
The wiring width of the connecting electrode portions 23b and 24b is equal to that of the parallel electrode portion 23.
It is formed so as to be wider than the wiring width of a and 24a. The electrodes 23 and 24 are arranged so as to be staggered from each other by a 1/2 pitch. Also, the connecting electrode portion 23
Conductors 27 and 28, which are connected to an external power source, are connected to b and 24b, respectively. When the electrodes 23 and 24 of the stator 2 are combined with the stator 1, their parallel electrode portions 23a,
24a is between the parallel electrode portions 13a and 14a of the stator 1,
The stator 1 is arranged so as to be offset by one pitch from the electrodes 13 and 14 so as to face a portion where no electrode is formed.

On the other hand, the mover 3 has the same pitch as the main body 34 extending in the longitudinal direction and the electrodes 13, 14, 23, 24 of the stators 1, 2 and extends in the direction orthogonal to the main body 34. And a comb tooth-shaped electrode 35. It should be noted that the pads 32 for connecting the conducting wires 39 are provided at both ends of the main body 34.
a and 32b are provided. Then, the mover 3 is connected to an external power source through this conductor portion, and the potential is adjusted by this.

The stators 1 and 2 are joined via the spacers 4a and 4b. When assembling these spacers 4a and 4b,
For example, the mover 3 is tightly joined to the stators 1 and 2 by using adhesion or anodic bonding, and the mover 3 is located in the space surrounded by the spacers 4a and 4b and the two stators 1 and 2.

Instead of providing the conductive wire 39 on the mover 3, the spacers 4a and 4b provided outside the comb tooth-shaped electrode 35 of the mover 3 are connected to an external power source or a connected conductive wire to form a mover. Electrical contact may be realized by contacting the electrode 35 with the spacers 4a and 4b while the stator 3 repeats contact and peeling between the stators 1 and 2. In addition, the mover 3
The outer shape does not necessarily have to be processed in this way, and electrodes 34 and 35 having a shape as shown in FIG. 10 may be formed on the front and back of a flat plate made of an insulating material.

Next, the structures of the stator 1 (the stator 2 has the same structure) and the mover 3 will be further described with reference to FIG. Stator 1
The base material 10 is not particularly limited as long as it is an insulator or a substance having an extremely high electric resistance, but, for example, a glass wafer can be used. On the base material 10 of this stator 1,
First, the conductive films 13a and 14a are formed. Although this embodiment does not limit the manufacturing method of the actuator,
For example, it may be formed by bonding a thin metal plate, a thin film forming means such as sputtering or vapor deposition, photolithography,
It may be formed by an etching process. Conductive film 1
An insulating film 19 is formed on 3a and 14a. This may be done by adhering a thin sheet made of a material having a high electric resistance, for example, by sputtering or various CVs.
A silicon oxide film may be formed by the D method or the like. The conducting wire is connected to a part of the electrode by using a means such as bonding with a conductive adhesive or bonding.

On the other hand, the mover 3 is a conductor or a resistor 3.
The upper and lower sides of the first electrode portion are covered with the insulating film 38. The mover 3 may be formed by forming a conductive film processed into a pattern of electrodes on the upper and lower sides of the insulator and covering the surface thereof with an insulating film. The tooth-shaped concave portion of the comb is not necessarily penetrated, and the tooth-shaped convex portion and the concave portion of the comb may be stepped. It may be created by forming a conductive film and an insulating film on the surface of the base material.
Similar to the above-described stator 1, the method of construction may be a thin metal plate or an insulating sheet, or a vapor phase growth method such as sputtering, vapor deposition, or CVD. For example, it may be formed by forming a conductive metal thin film and an insulating film on the surface of a silicon thin plate or by forming an insulating film on the surface of a silicon conductive plate.

Regarding the spacers 4a and 4b, for example,
The spacers 4a, 4b and the mover 3 are manufactured using a silicon wafer as a material by using a semiconductor manufacturing technique, and the silicon wafer is sandwiched between glass wafers (stators 1 and 2), and the three members are anodically bonded. Alternatively, it may be formed by integrally molding. Positioning accuracy is good when integrally molded. Moreover, in order to measure the electrical connection with the mover 3 by using the spacers 4a and 4b, the spacer is made of a conductive material, or a conductive film is formed on the surface of the spacer, and a conductive adhesive or bonding is used. May be used to connect or ground to an external power source.

Next, the operation of this embodiment will be described with reference to FIGS. 12 and 13. This operation sequentially applies a voltage to each electrode 23, 14, 24, 13 of the stator 1, 2,
This is an example in which the movable element 3 is driven to the right side in FIG. 12 while alternately repeating attraction between the stators 1 and 2. Mover 3
The potential of is always negative or 0 (the potential of the lead wire 39 is always dropped to negative or ground),
Voltages are applied in order of the electrodes 23, 14, 24, 13 of the stators 1, 2. For example, when a positive voltage is applied to the electrode 23, the mover 3 is attracted to the stator 2 by the electrostatic force generated between the electrode 23 and the electrode portion 35 of the mover 3, as shown in step (a). It becomes a positional relationship. Here, when the voltage application to the electrode 23 is stopped and a positive voltage is applied to the electrode 14, the mover 3 separates from the stator 2 and the electrostatic attraction between the mover 3 and the other stator 1 causes the stator 1 to move. Attracted and finally touched. At this time, the mover 3 is attracted to the stator 1 while being drawn to the right side in FIG. 12 depending on the positions where the electrodes of the mover 3 and the stator 1 are formed.

For example, the electrode portion 14 of the stator 1 and the mover 3
This will be described in more detail by taking c, 14b and 35b as examples. When the voltage is switched from the electrode 23 to the electrode 14, the electrode portion 35b of the mover 3 becomes the electrode portions 14c, 1 of the stator 1.
4b is attracted by electrostatic force. Since the attraction force of the electrode 14c is larger than the attraction force of the electrode 14b, the mover 3 is in the state shown in step (b). After that, the voltages to the electrodes 23, 14, 24, 13 of the stators 1 and 2 are sequentially switched to attract the stator 3 to the stator 1 and 2 of the mover 3,
By repeating the peeling, the mover is driven to the right side in FIG. 12 while sequentially taking the states shown in steps (a) to (d) of FIG. FIG. 13 shows a voltage application pattern to the electrodes 23, 14, 24 and 13 of the stators 1 and 2 at this time. When this voltage application pattern is changed in the order of electrode 23 → electrode 13 → electrode 24 → electrode 14, the mover 3 is driven to the left side in FIG.

Next, a fifth embodiment of the electrostatic actuator according to the first invention will be described with reference to FIG. The electrostatic actuator of this embodiment has a stator 1 as shown in FIG.
Alternatively, a conductive electrode 61a is formed on the second base material 61,
An insulating layer 61b is formed so as to cover the electrode 61a. A conductive electrode 63a is formed on the base material 63 of the mover 3, and the insulating layer 6 is formed so as to cover the conductive electrode 63a.
3b is formed. The opposite surface of the mover 3 (see FIG.
Similarly, a conductive electrode and an insulating layer are provided also on the lower side surface in FIG. 4, and a stator is provided on the surface facing the conductive electrode and the insulating layer, but they are omitted. In such a case, the insulating layers 61b of the stators 1 and 2 and the insulating layer 63b of the mover 3 are made of the same material. If the stators 1 and 2 and the electrodes 61a and 63a of the mover 3 have an insulating layer 61
b and 63b are formed of different materials, or an insulating layer is formed only on one electrode portion of the stator and the mover and the conductive electrode is directly exposed on the other electrode portion, the stator 1
Alternatively, 2 (omitted in FIG. 14) and the mover 3 are charged by direct contact or friction so that the combination of materials of each insulating layer or the combination of the insulating layer and the conductive electrode does not depend on whether the voltage applied to the electrode is positive or negative. Depending on the combination of materials, the insulating layer will be charged with a positive or negative fixed polarity. For this reason, the charges electrostatically attract the electrodes to each other, which makes peeling difficult and makes smooth adsorption and peeling difficult.

In the fifth embodiment, insulating layers 61b and 63 are used.
By forming b from the same material, it is possible to prevent the electrode parts from being attracted to each other due to charging due to contact or friction.

Next, a sixth embodiment of the electrostatic actuator according to the first invention will be described with reference to FIG. The electrostatic actuator of this embodiment is an electrostatic actuator in which a pair of electrodes are provided in the driving electrode portions of the stators 1 and 2 and the mover 3 and the repulsive force is used in addition to the attraction force by static electricity.

Electrodes 73 and 74 are formed on both the front and back surfaces of the base materials of the stators 1 and 2, and an insulating layer 75 is formed on the surface facing the mover 3 so as to cover the electrode portions. When a voltage is applied as shown in FIG. 15, the mover 3 is pulled by the stator 1 by the electrostatic attraction force due to the electric charges appearing on the stator 1, and the mover 3 is also applied to the electrode 73 of the other stator 2. Due to the appearing electric charge, an electrostatic repulsive force is received and a force in a direction away from the stator 2 is obtained. This is the stator 1 and 2, the mover 3
Since a pair of electrodes is provided on each of the driving electrodes, the electric charges of the same polarity appearing on the opposite electrodes are prevented from moving away from the opposite surface, and the electric charges of the same polarity are left on the surface as much as possible. This is because. Therefore, the mover 3 can drive the mover 3 by obtaining a repulsive force in addition to the attraction force by static electricity. Further, the electrode paired with the driving electrode may be installed via an insulator 77 as shown in FIG. 15, or when the stators 1 and 2 are provided so as to be located above and below, A pair of electrodes may be provided on the side surface.

FIG. 16 shows a case where the electrostatic actuator of the fourth embodiment of the first invention is applied to a pan-tilt pan head. FIG. 16 shows an example in which three electrostatic actuators 81, 82 and 83 in the fourth embodiment are used and applied to a pan / tilt pan head. As shown in FIG. 16, this actuator is shaved at three places on a cylinder 85 and placed on the three planes that appear. Each electrostatic actuator can be driven in one direction (forward and backward) of the arrow in FIG. 16 by sequentially applying a voltage to the drive electrode 84. An elastic support portion 86 is provided on the central axis of a member 85 to which the actuators 81, 82, 83 are attached, and a pan head bottom portion 87 for pan-tilt operation is provided thereon. The movable table of the driven electrostatic actuator is brought into contact with the elastically supported platform bottom portion 87 and pushed to drive the platform. Three
Since one electrostatic actuator is installed in three directions and each operates independently, pan-tilt drive of the pan head is realized by appropriately adjusting each drive voltage pattern.

[0060]

According to the first aspect of the present invention, the problem of friction between the mover and the stator can be solved and a large operating range can be obtained. In addition, contact / peeling can be performed smoothly. Further, not only the suction force but also the repulsive force can be used to obtain a large output.

According to the second invention, it is possible to smoothly carry out contact and peeling.

[Brief description of drawings]

FIG. 1 is an exploded view showing a configuration of a first embodiment of an electrostatic actuator according to the first invention.

FIG. 2 is a sectional view showing a detailed structure of a stator and a mover according to the first embodiment.

FIG. 3 is an operation explanatory diagram illustrating an operation of the first embodiment.

FIG. 4 is a waveform diagram of a voltage applied to the first embodiment.

FIG. 5 is an operation explanatory diagram illustrating an operation of a modified example of the first embodiment.

FIG. 6 is a sectional view illustrating the configuration of the second embodiment.

FIG. 7 is a voltage waveform diagram used in the driving method according to the second invention.

FIG. 8 is a configuration diagram showing a configuration of a third embodiment of an electrostatic actuator according to the first invention.

FIG. 9 is a configuration diagram showing a configuration of a pan-tilt pan head using an electrostatic actuator according to a third embodiment.

FIG. 10 is an exploded view showing a configuration of a fourth embodiment of the first invention.

FIG. 11 is a sectional view illustrating a detailed structure of a stator and a mover according to a fourth embodiment.

FIG. 12 is an operation explanatory view explaining the operation of the fourth embodiment.

FIG. 13 is a waveform diagram of a drive voltage applied to the fourth embodiment.

FIG. 14 is a sectional view showing a configuration of a fifth embodiment of the first invention.

FIG. 15 is a configuration diagram showing a configuration of a sixth embodiment of the first invention.

FIG. 16 is a configuration diagram showing a configuration of a pan-tilt pan head using the electrostatic actuator according to the fourth embodiment.

FIG. 17 is a configuration diagram showing a configuration of a conventional electrostatic actuator.

FIG. 18 is an explanatory diagram illustrating the configuration and operation of another conventional electrostatic actuator.

[Explanation of symbols]

1, 2, 41, 42 Stator 3, 43 Mover 3a Conductors 3b, 3c, 11c, 12c Insulating film 10, 20, 34 Main body 11, 12, 13, 14, 21, 22, 22, 23, 24, 4
1a, ... 41d, 42a ,. 32b Pad 35 Comb-shaped electrode 40 Electrostatic actuator 41e, ... 41h, 42e, ... 42h Hole 44 Spacer

Claims (5)

[Claims] 1. A pair of stators, each of which has a main body and a plurality of electrodes formed on opposing surfaces of the main body, and which are arranged to face each other with a predetermined gap, and between the pair of stators. And a movable electrode advancing through the gap while being attracted to the pair of stators alternately from one end to the other end by applying a predetermined voltage pulse to the electrodes of the stator. An electrostatic actuator comprising: a child. 2. A first main body part, a plurality of parallel electrode parts arranged in parallel with a predetermined pitch, and a connection electrode part for connecting one end of these parallel electrode parts.
A first stator having a second electrode, wherein the first and second electrodes are alternately formed on the first main body, a second main body, and a predetermined pitch. Third and fourth electrodes each having a plurality of parallel electrodes arranged in parallel and a connecting electrode part connecting one ends of these parallel electrode parts;
And a second stator formed by alternately forming the third and fourth electrodes on the second main body portion, a main body electrode portion, and extending from the main body electrode portion in the shape of a comb tooth. A movable element having a plurality of comb-teeth-shaped electrodes, and the first and second stators are arranged to face each other with a predetermined gap, and the movable element is arranged in the gap. Electrostatic actuator. 3. A pair of stators each having an electrode and an insulating layer covering the electrode and being opposed to each other with a predetermined gap, an electrode and an insulating layer covering the electrode, and a space between the stators. An electrostatic actuator, comprising: a movable element arranged in a gap and movable in the gap, wherein the insulating layer of the stator and the insulating layer of the movable element are formed of the same material. 4. A pair of stators each having a driving electrode and arranged with a predetermined gap, and a mover having a driving electrode, arranged in the gap between the stators, and movable in this gap. An electrostatic actuator comprising: a stator and a mover, each of which is provided with a pair of electrodes for each driving electrode. 5. A pair of stators having electrodes and opposed to each other with a predetermined gap, and a pair of stators arranged in the gap between the stators and applying a voltage to the electrodes In an electrostatic actuator provided with the movers that are alternately attracted, the voltage applied to the electrodes when the movers are attracted is such that the absolute value of the voltage immediately after the application becomes the absolute value of the subsequent voltage value. A method for driving an electrostatic actuator, which is set to be higher than that of the electrostatic actuator.