JP3095642B2 - Electrostatic actuator and driving method thereof - Google Patents

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 an electrostatic force and a driving method thereof.

[0002]

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

FIG. 17 shows a typical example of an electrostatic actuator using the above method. The electrostatic actuator includes fixed electrodes 101, 10 on glass substrates 100a, 100b, respectively.
Stators 104a and 104b on which 2, 103 are formed;
A mover 105 made of silicon and elastic support portions 106a, 1
The movable element 105 is driven in the direction of the arrow shown in FIG. 17 by electrostatic force generated when a voltage is applied between the fixed electrodes 101, 102, 103 of the stators 104a, 104b and the movable element 105. Is what you do. FIG.
The elastic actuators 106a, 10
6b is not provided, the fixed electrodes 101, 102,
When voltages having phases shifted by ３ each other are sequentially applied to 103, the mover 105 becomes the stator 104 a or 10
4b, the movable element 1 is moved by the frictional force generated at this time.
05 becomes difficult. Therefore, in the electrostatic actuator shown in FIG. 17, elastic supports 106a and 106b are provided to elastically support the mover 105, and the stators 104a and 104b
Drive is performed 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 is a stator 1 on which electrodes 120a, 120b, 120c are formed.
A movable element 124 composed of a high-resistance element 122 and an insulator 123 is placed on the electrode 21, and the electrodes 120 a, 120 b, 120 c
18 (a),
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 are in contact with each other, attracted to each other, and the operation is difficult due to a frictional force. Therefore, in the electrostatic actuator shown in FIG. 18, a method utilizing a repulsive force of static electricity is employed. That is, for example, when a positive voltage is applied to the electrode 120a in a state where the movable element 124 is attracted to the stator 121, the corresponding portion B of the opposed movable element 124 is negatively charged by electrostatic induction (FIG. 18).
(See (a) and (b)). When the voltage of the electrode 120a is rapidly switched to negative in this state, the movable member 124 and the stator 121 are momentarily slightly separated from each other due to the repulsive force of the negative charge charged in the portion B, and the positive charge appearing on the electrode 120b. The mover 124 is moved by the attraction force.

[0005]

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

However, in the electrostatic actuator using the above-described method, it is difficult to realize a large operation range because the movable element is elastically supported.

Further, in the electrostatic actuator using the above-mentioned method, since a relatively complicated physical phenomenon is used, the design is not always easy.
The material properties (permittivity, resistivity) of the stator could not always be freely selected. Also, the drive power supply needs to be devised in terms of switching speed and the like.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an electrostatic actuator capable of obtaining a large operating range and capable of smoothly repeating adsorption and separation, and a method of driving the same.

[0009]

According to a first aspect of the electrostatic actuator according to the first aspect of the present invention, the electrostatic actuator includes a main body, and a plurality of electrodes formed on opposing surfaces of the main body.
From one end to the other end by applying a predetermined voltage pulse to a pair of stators and a pair of stators disposed opposite to each other with a predetermined gap and being disposed between the pair of stators, and applying an electrode of the stator to a predetermined voltage pulse. And a mover that sequentially moves 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 is connected to a plurality of parallel electrode portions arranged in parallel at a predetermined pitch and one end of each of the parallel electrode portions. A first stator having first and second electrodes each having a connection electrode portion to be connected, and a first stator formed by alternately forming the first and second electrodes on the first main body portion; A second body portion, and third and fourth electrodes each having a plurality of parallel electrodes arranged in parallel at a predetermined pitch and a connection electrode portion for connecting one end of these parallel electrode portions. A second stator in which the third and fourth electrodes are alternately formed on the second main body, a main body electrode, and a plurality of comb-shaped teeth extending from the main body electrode. A movable element having a comb-shaped electrode; and wherein 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 aspect of the present invention, a pair of stators each having an electrode and an insulating layer covering the electrode, the pair of stators being opposed to each other with a predetermined gap, An insulating layer that covers an electrode, and a movable element that is disposed in a gap between the stators and that can move through the gap.The insulating layer of the stator and the insulating layer of the movable element are made of the same material. It is characterized by being formed.

In a fourth aspect of the electrostatic actuator according to the first invention, each has a pair of stators each having a drive electrode and arranged with a predetermined gap, and a drive electrode.
A movable element disposed in a gap between the stators and movable in the gap, wherein the stator and the movable element are provided with electrodes that are paired with respective drive electrodes.

According to a second aspect of the present invention, there is provided a driving method of an electrostatic actuator, comprising: a pair of stators having electrodes and opposed to each other with a predetermined gap; Is applied, and a movable element is alternately attracted to the pair of stators.In the electrostatic actuator including the movable element, the voltage applied to the electrode when the movable element is attracted is the voltage immediately after the application. 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 according to the first aspect of the present invention, if two or more electrodes are formed on one stator, the movable element can be used as the stator. When adsorbing, instead of adsorbing the mover at once, it is possible to adsorb one side of the mover first and adsorb the other side later. When the mover is attracted in this manner, the mover moves to the side to be attracted with a slight delay. By repeating this at high speed many times, the mover can move in a large range.

Further, according to the second aspect of the electrostatic actuator of the first aspect of the present invention, two or more phases of parallel pattern-shaped electrodes are provided on each of the stators, and the movable elements located therebetween are provided on the stator. 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 a voltage is sequentially applied to the electrodes of each phase of the stator so as to correspond to at least one phase electrode of the stator. For a mover having a simple parallel-patterned electrode, the mover can be alternately attracted to its corresponding stator electrode, thereby realizing a very small amount of movement.

Further, according to the third aspect of the electrostatic actuator of the first aspect of the present invention, the material of the insulating layer of the electrode portion at the place where the stator and the mover come into contact is the same. As a result, it is possible to prevent the stator and the mover from continuing to be attracted to each other due to electrostatic charging, and to realize smooth separation.

Further, according to the fourth aspect of the electrostatic actuator of the first aspect, the stator and the mover are provided with electrodes that are paired with the respective drive electrodes. The generated charges can be collected on the surfaces of the driving electrodes facing each other as much as possible, and it becomes possible to use the repulsive force together with the attraction force due to static electricity for each driving electrode,
Large output and smooth driving can be realized.

Further, according to the driving method of the electrostatic actuator of the second invention, a high voltage is applied instantaneously immediately after the voltage is applied, and the voltage is dropped when the mover approaches the stator.
As a result, a movable element at a distant position can be attracted by a large electrostatic force, and even if the movable element and the stator approach each other, discharge or dielectric breakdown of an 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.

FIG. 1 shows the configuration of a first embodiment of the electrostatic actuator according to the first invention. The electrostatic actuator of this embodiment includes a pair of stators 1 and 2 which are arranged to face each other.
, A mover 3, and spacers 4a and 4b.
The stator 1 is made of a material having an extremely high electric resistance (for example, glass).
The main body 10 is formed of a plate having two electrodes 11 and 12 formed on a surface of the main body 10 facing the stator 2. The stator 2 also has a main body 20 made of a plate of a material having extremely high electric resistance.
, Two electrodes 21 and 22 are formed on a surface facing the stator 1. The electrode 11 of the stator 1 is formed to extend from one end to the center of the main body 10, 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 each end, and these side portions 11b and 12
b, conductors 15, 1 for applying a voltage from outside, respectively.
6 are connected. Also, the electrodes 21 and 22 of the stator 2
Are also formed to extend from each end to the center, and also extend to the side surface of the corresponding end. Conductive wires 25 and 26 for applying a voltage from outside are connected to these side portions 21b and 22b, respectively.

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

As shown in FIG. 2, the two electrodes 11 and 12 of the stator 1 have conductive films 11a and 12a formed 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 bonding a metal thin film to the main bodies 10, 20 or by depositing a conductive film on the main bodies 10, 20 by means such as sputtering or vapor deposition, and by using an etching process or the like. It may be formed by patterning. The insulating films 11c and 12c may be formed by bonding a thin sheet made of a substance having a high electric resistance on the conductive film, or may be formed by a sputtering method or a CVD method.
It may be formed by depositing a silicon oxide film using a method. The conductive wires 15 and 16 are bonded by using a conductive adhesive or are bonded by using a 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 bonded to a 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 metal film formed on the surface of silicon.

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 the materials of the stators 1 and 2, and the spacers 4a and 4b are formed 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. FIG. 3 is a process chart for explaining the order of operation, and FIG. 4 is a diagram showing 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 the electrodes 11, 12, 21, and 22, and the mover 3 is moved to the left in FIG. The potential of the mover 3 is always set to 0 (grounded via the conducting wire 33), and the potential of each electrode is sequentially switched to 0 or a predetermined value V. V may be positive or negative. Therefore, for example, when the potential of a certain electrode is V, a potential difference occurs between the movable element 3 and
The mover is attracted to the electrode by the electrostatic force. FIG. 3 is 4
Consists of two steps.

First, in step (a), the electrodes 11, 1
2, the potentials V ₁₁ , V ₁₂ are V, and the potentials V ₂₁ ,
A state where V ₂₂ is set to 0 (see FIG. 4), when the movable element 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 from this state (time t _{1 in} FIG. 4), the mover 3 enters the state of step (b). At this time, at the time of 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 leftward by δ in FIG. You can see that Next, the potential V of the electrode 22
₂₂ switching the electric potential V ₁₂ of the electrode 12 to 0 V (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 shifts to the state of step (d). Again moves to the left in FIG. 3 by δ. Further, 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 attracted to the stator 1 again (see step (e)). During this sequence of 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. If the potentials of the electrodes 11, 12, 21, 22 are switched in the reverse order of the above-described steps, the mover 3 moves to the right in FIG. .

As described above, according to the present embodiment, a larger operation range can be obtained as compared with the conventional case, and the suction / peeling can be smoothly repeated.

In the above embodiment, the stator 1
Although an insulating layer is formed on both the mover 2 and the mover 3,
If an insulating layer is formed on one of the stators 1 and 2 and the mover 3, it is needless to say that the same effect as in the present 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
Is a case in which the bending rigidity is relatively high, that is, the case where the mover 3 has a thickness, or a case where the mover 3 is made of a relatively hard material. This is an example of a case in which it is made of a soft material such as a conductive rubber or a polymer film, has low bending rigidity, and is liable to bend. In this modification, the electrode 1
Assuming that the pattern of application of the potential to 1, 12, 21, and 22 is the same as that of the first embodiment, the movable element 3 is different from that of the first embodiment.
Since the bending rigidity is low, the mover 3 moves between the counter electrodes while bending and deforming as shown in FIG. When the movable element 3 having a low bending rigidity is used as in this modification, the contact between the stators 1 and 2 and the movable element 3 is higher than when 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 movable element 3 having low bending rigidity, and has a large number of electrodes provided on the opposing surfaces of the stators 1 and 2 along the traveling direction of the movable element 3.

That is, the stator 1 is moved along the moving direction of the mover 3.
Multiple electrodes 13 _1, ... 13 ₁₀ is provided on the stator 2
Are provided with a large number of electrodes 23 ₁ ,..., 23 ₁₀ .
Now, the potential of the mover 3 is set to 0, and 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. , And the remaining electrodes 13 ₄ ,..., 13 ₁₀ and 23 ₁ ,.
_{Assume that} the voltage of ₄ is set to 0. In this state, the mover 3 is in a state drawn by a solid line shown in FIG. From this state, the electrodes on the stator 1 are applied sequentially from the left,
When the upper electrode is grounded to the 0 potential in order from the left, the mover is gradually attracted to the stator 1 side from the left side, passes through the state shown by the dotted line, and finally to the stator 1 side. Move completely. Thus, by forming a large number of electrodes on the stators 1 and 2 and sequentially switching the electrodes, it is possible to reliably move between the two stators while deforming the mover 3.

In the above description, an example has been described in which the movable element 3 on the stator 2 side is switched to the stator 1 side. However, the switching from the stator 1 side to the stator 2 side is exactly 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 in the} voltage pattern shown in FIG. 7 are applied to the electrodes 12 and 22 of the stator 2. In the voltage pattern voltage pattern shown in FIG. 4 shown in FIG. 7, when the applied voltage rises from 0 to a predetermined value V, the high voltages V ₁ than the predetermined value V time Delta] t (e.g., application of a predetermined value V 1ms if the time is 10ms
ec) and then decrease 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 having a value of 0 is applied to the electrodes 21 and 22 of the stator 2 (between times t _{0 and} t _{1 in} FIG. 7), the mover 3 is attracted to the stator 1, that is, the mover 3 is an electrode 21
It is located far away from. In general, 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) in FIG.
Is weak to attract the electrode 21 to the electrode 21 side. Therefore, as shown at time t ₁ in FIG. 7, a high voltage V ₁ is applied only immediately after switching of the voltage (immediately after application), and a voltage of a predetermined value V is applied to the electrode 18 when the mover 3 approaches the electrode 18.

As described above, when the movable element that has been attracted to one stator is attracted to the other stator by switching the voltage applied to the electrode of the other stator, a high voltage is applied only immediately after the voltage is switched. 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, thereby discharging or insulating the insulating film formed on the electrode of the stator or mover. Destruction can be prevented.

In the driving method of this embodiment, the electrostatic actuator used is described with reference to FIG. 1. However, in general, a movable element that moves between stators while being alternately attracted to two stators is used. It is needless to say that the present invention can also be applied to an electrostatic actuator having

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 the electrostatic actuator 40 of this embodiment.
8B is a cross-sectional view taken along a cutting line ZZ shown in FIG. 8A. The electrostatic actuator 40 of this embodiment includes two stators 41 and 42 and a movable element 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.
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 example, a metal thin film is formed by vapor deposition, and an insulating film of a silicon oxide film is formed thereon by, for example, sputtering. The stator 41 has a relatively large hole 41i in the center and small holes 41e, 41f, 41g on four sides.
41h has been opened. These four holes 41e, 41
f, 41g, 41h have conductors 45a, 45b, 45c,
45d is inserted, fixed with a conductive adhesive, and electrically connected to the respective electrodes 41a, 41b, 41c, 41d.

On the other hand, the mover 43 (indicated by a dotted line on FIG. 8A) is made of, for example, a silicon wafer, a metal film is formed on both sides of the silicon wafer, and a silicon oxide film is formed thereon as an insulating film. You. A small hole 43h is formed in the center of the mover 43, and no insulating film is formed around the small hole 43h. The movement of the mover 43 can be extracted to the outside by passing a conductive shaft (not shown) through the hole, and the potential of the mover 43 can be adjusted from the outside through the shaft (this will be described later). ).

The spacers 44 are provided on four sides to maintain a 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 for bonding with the stators 41 and 42.

Next, the operation will be described. The actuator 40 has eight electrodes 41a,... 41d, 42a,... 42d, which are combined by two stators 41, 42. Can be operated in the same manner. That is, the stator 4
One electrode 41a and 41d, 41b and 41c, stator 42
Electrodes 42a and 42d and 42b and 42c
When viewed as one electrode in the embodiment, it can be operated in the X direction. Similarly, electrodes 41a and 41
b, 41c and 41d, 42a and 42b, 42c and 42d
Can be operated in the Y direction if each is viewed as one electrode in the first embodiment. As described above, 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 a pan / tilt 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 at the center of the concave portion of the support member 51. A pivot 50a is provided at one end of the shaft 50 on the support member 51 side.
Are formed, and 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 is prevented from coming off on the side of the actuator 40 opposite to the support member 51. A movable pan / tilt portion is attached to the end of the shaft 50 opposite to the pivot 50a.

In the pan / tilt head thus configured, the actuator 40 is driven, and the movable element 43 is moved to the position shown in FIG.
When operated in the X direction shown in FIG.
2 performs a rocking motion in the ψ _Y direction, and the mover 43
When operated in a direction, the pan and tilt movable portion 52 carries out an oscillating motion of the [psi _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 maintaining a gap between the two stators 1 and 2.

The stator 1 has a structure in which two electrodes 13 and 14 are provided on a surface of the main body 10 made of an insulator or a material having 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 connection electrode portion 13b connecting one end of these parallel electrode portions 13a. Similarly, the electrode 14 includes a plurality of parallel electrode portions 14a arranged in parallel with a predetermined pitch P, and a plurality of parallel electrode portions 14a.
a for connection to one end of the connection electrode a. The wiring width of the connection electrode portions 13b and 14b is formed to be wider than the wiring width of the parallel electrode portions 13a and 14a. Then, the electrodes 13 and the electrodes 14 are arranged so as to be staggered and shifted by a half pitch. The connection electrodes 13b and 14b have lead wires 17 and 1 connected to an external power supply.
8 are connected.

Similarly to the stator 1, the stator 2 has a main body 20 made of an insulating material or a material having an extremely high electric resistance.
, Two electrodes 23 and 24 are provided on a surface 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. The electrodes 24 are arranged in parallel with a pitch P. And a plurality of parallel electrode portions 24a, and a connection electrode portion 24b for connecting one end of each of the parallel electrode portions 24a.
The wiring width of the connection electrode portions 23b and 24b is
a, 24a are formed to be wider than the wiring width. The electrodes 23 and the electrodes 24 are arranged so as to be shifted from each other by a half pitch. Also, the connection electrode portion 23
Conductors 27 and 28 connected to an external power supply are connected to b and 24b, respectively. When the electrodes 23 and 24 of the stator 2 are combined with the stator 1, the parallel electrode portions 23a and
24a is between the parallel electrode portions 13a, 14a of the stator 1,
The arrangement is shifted by one pitch with respect to the electrodes 13 and 14 of the stator 1 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 and 2, and extends in a direction perpendicular to the main body 34. And a comb-shaped electrode 35. In addition, pads 32 for connecting the conducting wire 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 supply through this conductor, and the potential is adjusted thereby.

The stators 1 and 2 are joined via spacers 4a and 4b. These spacers 4a and 4b are
For example, the movable element 3 is closely adhered to the stators 1 and 2 by using bonding or anodic bonding, and is located in a space surrounded by the spacers 4a and 4b and the two stators 1 and 2.

Instead of providing the movable element 3 with the conducting wire 39, spacers 4a and 4b provided outside the comb tooth-shaped electrode 35 of the movable element 3 are connected to an external power source or a connected conducting wire. The electrical connection may be realized by the electrode 35 being in contact with the spacers 4a and 4b while the stator 3 repeatedly contacts and separates the stators 1 and 2. In addition, mover 3
It is not always necessary to process the outer shape in this way, and electrodes 34 and 35 having shapes as shown in FIG. 10 may be formed on the front and back of a flat plate made of an insulator.

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 extremely high electric resistance. For example, a glass wafer can be used. On the base material 10 of the stator 1,
First, conductive films 13a and 14a are formed. This embodiment does not limit the method of manufacturing the actuator,
For example, it may be formed by bonding a metal thin plate, or a thin film forming means such as sputtering and 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 achieved, for example, by bonding a thin sheet made of a material having a high electric resistance, or by, for example, sputtering, various CVs.
A silicon oxide film may be formed by a method D or the like. The conductive wire is connected to a part of the electrode by using a conductive adhesive or bonding or other means.

On the other hand, the mover 3 is a conductor or a resistor 3
The upper and lower electrodes are covered with an insulating film 38. Note that a movable film 3 may be formed by forming a conductive film processed into an electrode pattern shape on the upper and lower sides of the insulator, and covering the surface with an insulating film. (The comb-shaped concave portion of the comb does not necessarily have to penetrate, and it is sufficient if a step is formed between the comb-shaped convex portion and the concave portion of the comb). It may be formed by forming a conductive film and an insulating film on the surface of the base material.
Similar to the above-described stator 1, the structure may be formed by using a thin metal plate or an insulating sheet, or by using a vapor deposition 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.

For the spacers 4a and 4b, for example,
Using a silicon wafer as a material, spacers 4a and 4b and a movable element 3 are manufactured by using a semiconductor manufacturing technique, and a glass wafer (stators 1 and 2) is configured so as to sandwich the silicon wafer. In other words, it may be made by integrally molding. When integrally molded, the positioning accuracy is good. Further, in order to measure electrical connection with the mover 3 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 a bonding agent is used. May be used to connect or ground to an external power supply.

Next, the operation of this embodiment will be described with reference to FIGS. In this operation, voltages are sequentially applied to the electrodes 23, 14, 24, and 13 of the stators 1 and 2,
In this example, the mover 3 is driven rightward in FIG. 12 while alternately repeating the attraction between the stators 1 and 2. Mover 3
Is always negative or 0 (always keep the potential of the conductor 39 negative or ground),
Voltage is applied to the electrodes 23, 14, 24, 13 of the stators 1, 2 in this order. For example, when a positive voltage is applied to the electrode 23, the movable element 3 is attracted to the stator 2 by the electrostatic force generated between the electrode 23 and the electrode portion 35 of the movable element 3, and 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 due to electrostatic attraction between the mover 3 and the other stator 1, the mover 3 is applied to the stator 1. Attracted and finally touched. At this time, the mover 3 is attracted to the stator 1 while being pulled to the right in FIG. 12 depending on the positions where the electrodes of the mover 3 and the stator 1 are formed.

For example, the electrode portions 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 portion 14c, 1 of the stator 1.
By 4b, it is sucked by electrostatic force. Since the attraction force by the electrode 14c is greater than the attraction force by the electrode 14b, the mover 3 is in a state as shown in step (b). Thereafter, the voltage to the electrodes 23, 14, 24, and 13 of the stators 1 and 2 is sequentially switched to attract the movable element 3 to the stators 1 and 2,
By repeating the peeling, the mover is driven rightward 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, 13 of the stators 1, 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 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.
Or, a conductive electrode 61a is formed on the second base material 61,
An insulating layer 61b is formed 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 (FIG. 1)
Similarly, a conductive electrode and an insulating layer are also provided on the lower surface of FIG. 4, and a stator is provided on a surface facing the conductive electrode and the insulating layer, but these 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 formed of the same material. If the insulating layers 61 of the electrodes 61a, 63a of the stators 1, 2 and the mover 3,
If b and 63b are formed of different materials, or if an insulating layer is formed only on one of the electrodes of the stator and the mover and the conductive electrodes are directly exposed on the other electrode, the stator 1
Or 2 (omitted in FIG. 14) and the mover 3 by direct contact or electrification by friction, irrespective of the polarity of the voltage applied to the electrode, regardless of the combination of the materials of the respective insulating layers, Depending on the combination of materials, the insulating layer will be charged to either positive or negative fixed polarity. For this reason, the electrodes are electrostatically attracted to each other due to the electric charge, making it difficult to peel off and making it difficult to smoothly suck and peel off.

In the fifth embodiment, the insulating layers 61b, 63
By forming b with the same material, it is possible to prevent the electrode portions from being attracted to each other by 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 is provided on the drive electrode portions of the stators 1 and 2 and the mover 3, and a repulsive force is used in addition to a suction force by static electricity.

Electrodes 73 and 74 are formed on the front and back surfaces of the respective 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 electrostatic attraction due to the electric charge appearing on the stator 1, and is also moved to the electrode 73 of the other stator 2. The generated charge receives an electrostatic repulsion force, and a force in a direction away from the stator 2 is obtained. These are stators 1 and 2, mover 3
Since each driving electrode has a pair of electrodes, the same-polarity electric charge appearing on the opposing electrode is prevented from moving away from the opposing surface, and the same-polarity electric charge is left on the surface as much as possible. That's why. Therefore, the movable element 3 can obtain the repulsive force in addition to the suction force by the static electricity, and can drive the movable element 3. Further, as shown in FIG. 15, the electrodes to be paired with the driving electrodes may be provided via an insulator 77, or when the stators 1 and 2 are provided so as to be positioned above and below, A pair of electrodes may be provided on the side surface.

Next, FIG. 16 shows a case where the electrostatic actuator according to the fourth embodiment of the first invention is applied to a pan / tilt 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 head. As shown in FIG. 16, the present actuator is obtained by shaving three portions of a cylinder 85 and disposing them on the three appearing planes. Each electrostatic actuator can be driven in one direction (forward and backward) indicated by the arrow in FIG. 16 by sequentially applying a voltage to the drive electrode 84. An elastic support portion 86 is provided on a central axis of a member 85 to which the actuators 81, 82, and 83 are attached, and a bottom portion 87 of a pan head that performs a pan / tilt operation is provided thereon. The movable head of the electrostatic actuator to be driven is brought into contact with the elastically supported pan head bottom 87 and pressed to drive the pan head. 3
Since three electrostatic actuators are installed in three directions and operate independently, the pan / tilt drive of the camera platform is realized by appropriately adjusting the respective drive voltage patterns.

[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 operation range can be obtained. Further, the contact and peeling can be performed smoothly. In addition, a large output can be obtained using not only the suction force but also the repulsion force.

According to the second aspect, the contact and peeling can be performed smoothly.

[Brief description of the drawings]

FIG. 1 is an exploded view showing the 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 for explaining the 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 modification of the first embodiment.

FIG. 6 is a sectional view illustrating the configuration of a 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 the electrostatic actuator according to the first invention.

FIG. 9 is a configuration diagram showing a configuration of a pan-tilt head using the electrostatic actuator of the 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 diagram for explaining the operation of the fourth embodiment;

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

FIG. 14 is a sectional view showing the 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 head using the electrostatic actuator of 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 Conductor 3b, 3c, 11c, 12c Insulating film 10,20,34 Main body 11,12,13,14,21,22,23,24,4
41a,... 41d, 42a,. 32b Pad 35 Comb-like electrode 40 Electrostatic actuator 41e,... 41h, 42e,... 42h Hole 44 Spacer

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-5-111264 (JP, A) JP-A-2-211078 (JP, A) JP-A-3-169277 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) H02N 1/00

Claims (7)

(57) [Claims] 1. A pair of stators each comprising a main body, and a plurality of electrodes formed on opposing surfaces of the main body, and a pair of stators arranged to face each other with a predetermined gap, and a predetermined potential is applied. One end portion of the electrode made of the conductor and the other end provided by applying a predetermined voltage pulse to the electrode of the stator, the electrode being arranged between the pair of stators. And a movable element that advances through the gap while being alternately attracted to the pair of stators from the one end to the other end. Actuator. 2. An electrode of each of said pair of stators is covered by a first insulating layer, and an electrode of said mover is covered by a second insulating layer.
An electrostatic actuator as described. 3. A first electrode having a first main body, first and second electrode parts alternately arranged on the first main body in a predetermined direction at a predetermined pitch, and A first stator including: a first connection electrode unit that connects ends of the first electrode units; and a second connection electrode unit that connects ends of the second electrode units. A second electrode having a second main body, third and fourth electrode parts alternately arranged on the second main body in a predetermined direction at a predetermined pitch, and the third electrode part; A second stator comprising: a third connection electrode portion connecting the ends of the fourth electrode portion; and a fourth connection electrode portion connecting the ends of the fourth electrode portions. And a mover having an electrode portion composed of the following: wherein the first and second stators are configured such that the mover includes the first stator and the second stator. The movable element is configured to be opposed to each other with a predetermined gap for traveling while being attracted to each other, and the movable element is arranged in the gap, and the first and second electrodes and the electrode section of the movable element are configured. The first electrode of the first stator and the second electrode of the second stator are sequentially switched so that a predetermined potential difference is given between the first electrode and the second electrode of the second stator. Switching the first and second electrode portions and switching the third and fourth electrode portions within the second electrode to drive the mover in the predetermined direction or in the opposite direction, An electrostatic actuator wherein the first and second electrodes of the second stator are each covered by a first insulating layer, and the electrode portion of the mover is covered by a second insulating layer. 4. The electrostatic actuator according to claim 3, wherein said first insulating layer and said second insulating layer are made of the same material. 5. A first body and a second body which are opposed to each other at a predetermined interval, a first electrode formed on an opposite surface of the first body, and a second body. An electrostatic actuator comprising: a pair of stators each having a second electrode formed on an opposing surface of the pair; and a mover disposed between the pair of stators. A third electrode formed on the surface opposite to the opposing surface of the portion so as to be paired with the first electrode; and a third electrode formed on the surface opposite to the opposing surface of the second main body. Second
And a fourth electrode formed to be paired with the first electrode. 6. A pair of stators each having an electrode and opposed to each other with a predetermined gap, and disposed in a gap between the stators, and a voltage is applied to the electrodes to apply a voltage to the pair of stators. In the electrostatic actuator comprising: a movable element that is alternately attracted; and a voltage applied to the electrode when the movable element is attracted, the absolute value of the voltage immediately after the application is changed to the absolute value of the subsequent voltage value. A driving method for an electrostatic actuator, wherein the driving method is set to be higher than the above. 7. A first and a second main body which are opposed to each other at a predetermined interval, a first and a second electrode formed on opposing surfaces of the first main body, and A pair of stators having third and fourth electrodes formed on opposing surfaces of the main body portion, and a mover disposed between the pair of stators. A first potential is applied to the first and second electrodes, and a second potential lower than the first potential is applied to the third and fourth electrodes to move the movable element to the first and second electrodes. A first step of adsorbing to the second electrode; and setting the potential of the first electrode to the second potential and setting the potential of the third electrode to the first potential. A second end for adsorbing one end of the mover that has been adsorbed on the third electrode to the third electrode. And the step of setting the potential of the second electrode to the second potential and setting the potential of the fourth electrode to the first potential, thereby setting the other of the movable element that has been attracted to the second electrode. A third step of adsorbing an end to the fourth electrode; and setting the potential of the first electrode to the first potential and the potential of the third electrode to the second potential. A fourth step of adsorbing one end of the mover that has been adsorbed to the third electrode to the first electrode; and setting the potential of the second electrode to the first potential and the fourth electrode. A fifth step of causing the other end of the mover that has been attracted to the fourth electrode to be attracted to the second electrode by setting the potential of the mover to the second potential. Method for driving an electrostatic actuator.