JP2001346385A - Electrostatic actuator, method of driving the same actuator and camera module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a low price electrostatic actuator assuring excellent assembling property and mass-productivity. SOLUTION: This electrostatic actuator is provided with a first stator 2a including at least three systems of first electrodes A to C sequentially arranged in the predetermined direction, a second stator 2b provided opposed to a first stator 2a to include one system of a second electrode D extended in the predetermined direction, and a rotor 3 arranged between the first stator 2a and the second stator 2b to include a third electrode E including the electrode portion 3a opposing to the first electrode. In this electrostatic actuator, a voltage is alternately applied to the first electrode and second electrode so that the potential of the first electrode or second electrode becomes higher than the potential of the third electrode E and the rotor 3 is driven in the predetermined direction by sequentially changing over the system of the first electrode in the predetermined direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an electrostatic actuator driven by electrostatic force and a camera module using the same.

[0002]

2. Description of the Related Art The structure of a conventional electrostatic actuator and its driving method will be described with reference to FIG.

An electrostatic actuator (for example, Japanese Patent Application Laid-Open No.
Reference numeral 40367) 101 includes a mover 102 and two stators 103a and 103b sandwiching the mover 102 from above and below. Each of the stators 103a and 103b is provided with two systems of electrodes. The upper and lower stators have a total of four systems of electrodes A to D. In addition, the stator 1
The pitch and electrode width of each of the electrodes A to D provided on 03a and 103b and the electrode portion 104 of the mover 102 are the same. However, in the stators 103a and 103b, the electrodes are combined so that two systems of electrodes (for example, A and C) appear in order. In addition, the upper and lower pairs of stator electrodes (eg, A and B) are arranged so that their phases are exactly half way up and down.

Now, when a high voltage is applied to the electrode A, the electrode A
The movable element is attracted to the upper stator 103a (at a position where the electrode A and the electrode E overlap) by electrostatic force (Coulomb force) acting between the movable element 102 and the electrode E provided on the electrode portion 104 of the movable element 102. You. Subsequently, when the electrode to which a high voltage is applied is switched to the electrode B, the mover 102 becomes the lower stator 103b.
(At a position where the electrode B and the electrode E overlap).
As described above, when the electrode to which a high voltage is applied is sequentially switched in the order of electrode A → electrode B → electrode C → electrode D, the mover 102 vibrates vertically while microscopically, and macroscopically in FIG. To the right (one degree of freedom). If the order of applying the high voltage to the electrodes is reversed, and the order of electrode A → electrode D → electrode C → electrode B is set, the mover is driven to the left in the figure. However, in order to realize this drive, two stators 103a, 103
It is necessary to precisely control the phase between 3b and to accurately manufacture electrodes on two opposing surfaces of the mover 102. Therefore, the cost is high due to the time and labor required for assembly, and this has been a problem in realizing mass production.

Referring to FIG. 30, a method of applying a voltage in a conventional electrostatic actuator will be described. FIG. 29
The same reference numerals are used for the same parts as those shown in FIG.

As described above, the stators 103a, 103b
The movable element 102 is driven when a high voltage is sequentially applied to the four electrodes A and B arranged in the system. The behavior when a voltage is applied to the electrode A will now be described. Here, on the electrode,
As a countermeasure against dielectric breakdown, a dielectric film 105 or the like is coated (see, for example, Japanese Patent Application Laid-Open No. 8-14067). When a high voltage is applied to the electrode A, dielectric polarization 106 occurs in the dielectric film 105 coated so as to cover the electrode as shown in the figure. Subsequently, when a high voltage is applied to the electrode B, the mover 102 is originally set to the lower stator 103.
The movable element is driven so as to overlap with the electrode B by the action force that drives the electrode b (to the position where the electrode E overlaps with the electrode B). However, actually, the dielectric film 10 provided on the electrode A
The component of the dielectric polarization 106 at 5 also exerts an action force to keep the mover 102 attracted to the upper stator 103a (at the position where the electrode A and the electrode E overlap). Although the component due to the dielectric polarization 106 is minute as a potential level, the acting force by the electrode B provided on the lower stator 103b is relatively small because the distance to the object (the electrode portion 104 of the mover 102) is short. There is a possibility that the force becomes larger than the force that cannot be ignored. This is because the electrostatic force is inversely proportional to the square of the distance between the electrodes. For this reason, in the conventional electrostatic actuator 101, the driving of the mover 102 may be unstable. In addition, variations in the degree of charge leakage in the dielectric film 105 (time during which the dielectric polarization is eliminated) and the like have caused a decrease in reproducibility of the operation of the mover 102.

[0007]

As described above,
In the conventional electrostatic actuator 101, it is necessary to accurately control the phase between the upper and lower two stators 103a and 103b, and it is necessary to accurately manufacture electrodes on two opposing surfaces of the mover 102, which is required for assembly. Cost was higher than time and labor, and this was a problem in realizing mass production.

Further, in the conventional electrostatic actuator 101, there is a possibility that the driving of the mover 102 becomes unstable due to the influence of dielectric polarization generated in the dielectric film 105 coated on the electrodes.

Furthermore, the degree of leakage of the charges in the dielectric film 105 (the time during which the dielectric polarization is eliminated) and the like cause a decrease in the reproducibility of the operation of the mover 102.

Therefore, the present invention solves these problems,
Provided is an electrostatic actuator capable of improving the assemblability and mass productivity and realizing stable driving without variation, and a driving method thereof, and a camera using the electrostatic actuator as a focus adjustment mechanism The purpose is to provide modules together.

[0011]

According to the present invention, there is provided a first stator having at least three systems of first electrodes sequentially arranged in a predetermined direction, and a first stator including the first stator. A second stator, which is provided to face the stator and includes one system of second electrodes extending in the predetermined direction, and disposed between the first stator and the second stator. And the first
A movable element having a third electrode having an electrode portion facing the electrode, wherein the first electrode or the second electrode is set so that the potential of the first electrode or the second electrode is higher than the potential of the third electrode. And applying a voltage alternately to the second electrode and sequentially switching the system of the first electrode in the predetermined direction, thereby driving the mover in the predetermined direction. I do.

Here, the width of the electrode portion provided on the mover in the predetermined direction is 1.5 to 2.0 times the width of each electrode of the first electrode in the predetermined direction. desirable.

[0013] Further, a dielectric film provided so as to cover the first or second electrode may be further provided.

[0014] Further, a dielectric film provided so as to cover the third electrode may be further provided.

Furthermore, when the above-mentioned dielectric film is provided, when applying a voltage to the second electrode, a potential difference is applied so that the potential of the first electrode is lower than the potential of the third electrode. Means may be further provided.

Further, the movable element may have a surface orthogonal to the predetermined direction to be driven as an optical element surface.

Further, the first and second stators have a stopper protruding from the surface of the electrode on the surface on which the electrode is provided, and the movable element has a surface on which the third electrode is provided. May be provided with a region for sliding the stopper.

Further, the mover includes a stopper protruding from the surface of the electrode on the surface on which the third electrode is provided, and the first and second stators include a stopper on the surface on which the electrode is provided. May be provided with a region for sliding the stopper.

Further, the first stator comprises a first component, and the second stator comprises a second component. The stator is formed by connecting the first and second components. You may make it.

Further, in the present invention, a first stator having first electrodes sequentially arranged in a predetermined direction, and a first stator provided opposite to the first stator and arranged in the predetermined direction are provided. A second stator having two electrodes; and a third electrode disposed between the first stator and the second stator and facing the first electrode and the second electrode. A movable element, and applying a voltage alternately to the first electrode and the second electrode so that the potential of the first electrode or the second electrode is higher than the potential of the third electrode. An electrostatic actuator for driving the mover in the predetermined direction, the dielectric actuator being provided on a surface of the first or second stator so as to cover the first or second electrode. When a voltage is applied to the body membrane and the second electrode, the potential of the first electrode becomes Means for providing a potential difference so as to be lower than the potential of the third electrode. here,
The dielectric film may be provided on a surface of the mover so as to cover the third electrode.

Further, in the present invention, a first stator having first electrodes sequentially arranged in a predetermined direction, and a first stator provided to face the first stator and arranged in the predetermined direction are provided. 2
A second stator having electrodes, and a movable having a third electrode disposed between the first stator and the second stator and facing the first electrode and the second electrode; By applying a voltage to the first electrode and the second electrode alternately so that the potential of the first electrode or the second electrode is higher than the potential of the third electrode. An electrostatic actuator characterized in that the movable element is driven in the predetermined direction, wherein the first and second stators include a stopper protruding from a surface of the electrode on a surface on which the electrode is provided. Wherein the movable element includes a region for sliding the stopper on a surface on which the third electrode is provided. Here, the stopper may be provided on the mover, and a region for sliding the stopper may be provided on the first and second stators.

According to the present invention, there is provided a first stator having a first electrode group in which at least three electrodes to which voltages are applied in different orders are sequentially arranged in a predetermined direction; A second stator having a planar second electrode provided in opposition to the stator and extending in the predetermined direction, between the first stator and the second stator. A movable element provided with a first electrode portion facing the first electrode group and a second electrode portion facing the second electrode; and a movable element having a potential higher than the potential of the first electrode portion. The first electrode group and the second electrode are arranged such that the potential of any one of the first electrode group is higher or the potential of the second electrode is higher than the second electrode portion. For alternately applying a voltage to the first electrode group and sequentially switching the order of applying the voltage to the first electrode group. To provide an electrostatic actuator; and a road.

According to the present invention, there is provided a first stator having a first electrode group in which at least three electrodes to which voltages are applied in different orders are sequentially arranged in a predetermined direction; A second stator provided with a second electrode on a plane extending in the predetermined direction and provided between the first stator and the second stator. A method for driving an electrostatic actuator that is arranged and has a mover including a first electrode unit facing the first electrode group and a second electrode unit facing the second electrode, the method comprising: A voltage is applied such that the potential of any one of the first electrode group is higher than the potential of the first electrode unit, and the potential of the second electrode is higher than that of the second electrode unit. Voltage is applied to switch the electrodes of the first electrode group,
A voltage is applied so that the potential of the electrode is higher than the potential of the electrode part of the above, and a voltage is applied so that the potential of the second electrode is higher than the second electrode part. And a method of driving an electrostatic actuator, characterized by repeatedly applying a voltage.

According to the present invention, there is provided a first image pickup device in which at least three electrodes provided on the image pickup device and to which voltages are applied in different orders are sequentially arranged in a predetermined direction.
A first stator having a group of electrodes, and a second stator having a planar second electrode provided to face the first stator and extending in the predetermined direction. A first electrode unit disposed between the first stator and the second stator and facing the first electrode group, and a second electrode unit facing the second electrode; A movable element including an optical element that forms an image of light on the imaging element, and the potential of any one of the first electrode group is higher than the potential of the first electrode unit, or A voltage is alternately applied to the first electrode group and the second electrode, and a voltage is applied to the first electrode group so that the potential of the second electrode is higher than that of the second electrode portion. And a switching circuit for sequentially switching the order of operation. To provide.

[0025]

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

[First Embodiment] A first embodiment of an electrostatic actuator according to the present invention will be described with reference to FIGS.

FIG. 1 is a diagram showing a schematic configuration of an electrostatic actuator according to the present embodiment. In the electrostatic actuator shown in FIG. 1, a first stator 2a and a second stator 2b are arranged to face each other, and an arrow 2
The mover 3 is arranged so as to be slidable along the direction shown in FIG. Here, the first and second stators 2a, 2b
May be a flat plate or a semi-cylindrical plate. When the first and second stators 2a and 2b are plate-shaped, the movable element 3 is formed in a block or hollow block having a substantially flat surface facing the movable element 3 and the first and second stators 2a and 2b. When the two stators 2a and 2b have a semi-cylindrical plate shape, the mover 3 includes the first and second stators 2a and 2a.
It is formed in a cylindrical body or a hollow cylinder corresponding to the shape of 2b.

The electrostatic actuator 1 has three electrodes A, B, C arranged in a predetermined direction on one surface thereof.
(A first electrode), a second stator 2b having a uniform one-system electrode D (second electrode) on its surface, and a first stator 2b on its surface. An electrode portion 3a corresponding to the electrode pitch of the electrodes provided on the stator 2a and a flat electrode portion 3d corresponding to the second stator 2b, and both electrode portions 3a and 3d are maintained at the same potential. And a mover 3 having a system electrode E (third electrode).

The driving principle of the electrostatic actuator according to the present embodiment will be described with reference to FIG. First, when a voltage is applied to the electrode A provided on the stator 2 a to make the potential of the electrode A higher than the potential of the electrode E provided on the movable element 3, an electrostatic force acting between the electrode A and the electrode E The mover 3 is attracted to the first stator 2a by (Coulomb force). At this time, since the state in which the electrode A and the electrode portion 3a overlap exactly is the most stable, the mover 3 is connected to the electrode A and the electrode portion 3a.
a from the electrode A so as to overlap with a. Subsequently, when the electrode to which the voltage is applied is switched to the electrode D provided on the second stator 2b, the mover 3 is switched to the second stator 2b.
It is sucked to the b side. Further, when the electrode to which the voltage is applied is switched to the electrode B provided on the stator 2a, the movable element 3 is moved by the same mechanism as when the voltage is applied to the electrode A so that the electrode B and the electrode portion 3a overlap. Receives more acting force. Such a series of operations, that is, the voltage is changed from the electrode A →
An electrode D → electrode B → electrode D → electrode C → electrode D → electrode A is sequentially and repeatedly applied (electrodes A to C provided on the first stator 2a and electrodes D provided on the second stator 2b). And the electrodes provided on the first stator 2a are sequentially switched in the predetermined direction) so that the mover 3 microscopically vibrates up and down while macroscopically. It is driven in the direction in which the electrodes arranged on the first stator are arranged (right side in the figure).

If the order of applying voltage to the electrodes of the stators 2a and 2b is reversed (electrode A → electrode D → electrode C → electrode D → electrode B → electrode D → electrode A ...), the movable element 3 becomes macroscopic. Specifically, it is driven in a direction opposite to the above-mentioned direction (left side in the figure). In addition, in the electrodes A, B, and C of the first stator 2a, the phases of the respective electrodes are arranged in a nested manner by shifting the phase by 1/3 so that the electrodes of the respective systems appear in order (specifically). The configuration will be described later). Further, the electrode portion 3a of the mover 3
As shown in the figure, a conductive material may be provided with irregularities on its surface, or a conductive material may be uniformly provided on a flat surface and patterned at a predetermined pitch.

In order to drive the mover 3 as described above, the electrodes A, B, C, the electrode D, and the electrode E apply a voltage to the electrodes A, B, C, and D as shown in FIG. It is connected to a voltage source 42 that generates a voltage via a switching circuit 40 that determines the timing of application. The electrode E is
Grounded via this switching circuit 40, or
Connected to negative potential. This switching circuit 40
Is configured in a circuit substantially similar to that of FIG.
A fixed contact and a grounded fixed contact connected to each of the electrodes A, B, C and the electrode D, and a first movable contact connected to a voltage source 42 connected to these fixed contacts and a grounded or It is composed of a second movable contact connected to a negative potential. In this switching circuit 40, one of these fixed contacts is connected to a voltage source 42 via a first movable contact.
, The other fixed contact is grounded via the second movable contact, or is connected to a negative potential.

In the electrostatic actuator shown in FIG.
Specifically, the mover 3 is moved in the forward direction 24 and the backward direction opposite thereto as described below.

First, a voltage (high-level voltage or potential H in FIG. 2) is applied to the electrode A provided on the first stator 2a as shown in FIG. The provided electrodes E and D are grounded as shown in FIGS. 2 (e) and 2 (d), or a potential lower than the potential of the electrode A (low level voltage in FIGS. 2 (e) and 2 (d)). Alternatively, it is maintained at the potential L). As described above, the potential of the electrode A is set higher than the potential of the electrode E provided on the mover 3, and the other electrodes B, C, and D are grounded, or set to a low level voltage or potential L. When connected, an electrostatic force, that is, Coulomb force, is generated between the electrode A and the first mover electrode portion 3a, and the mover 3 is moved so that the first mover electrode portion 3a is attracted to the electrode A. Is sucked toward the first stator 2a. That is, since the state in which the electrode A and the first mover electrode portion 3a overlap with each other is the most stable, the mover 3
Receives an action force from the electrode A so that the electrode A and the first movable element electrode portion 3a overlap as indicated by an arrow 44.
Subsequently, the switching circuit 40 switches from the electrode A to the flat and widened electrode D provided on the stator 2b, and the high-level voltage H is applied to the electrode D as shown in FIG. Is maintained at the low level voltage L, the mover 3 separates from the electrode A and moves to the second stator 2.
It is sucked to the b side.

When the switching circuit 40 switches from the electrode D to the electrode B provided on the stator 2a,
A voltage is applied to the electrode B as shown in FIG. 2B, and a voltage between the electrode B and the first mover electrode portion 3a as shown by an arrow 46 is the same as when a voltage is applied to the electrode A. Electrostatic force, that is, Coulomb force is generated, and the mover 3 is attracted to the first stator 2a side so that the mover electrode portion 3a overlaps the stator electrode B. Subsequently, when the switching circuit 40 switches from the electrode B to the electrode D that spreads flat and a voltage is applied to the electrode D as shown in FIG.
The mover 3 is separated from the stator electrode B and moves to the second stator 2b.
Sucked on the side.

Further, when switching is performed from the electrode D to the third electrode C by the switching circuit 40, a voltage is applied to the electrode C as shown in FIG. Similarly, an electrostatic force, that is, a Coulomb force is generated between the electrode C and the electrode portion 3a as shown by an arrow 48,
The mover 3 is sucked toward the first stator 2a so that the electrode portion 3a overlaps the electrode C. Subsequently, when the voltage is applied to the electrode D by switching from the third electrode C to the electrode D spreading flat by the switching circuit 40,
The mover 3 is separated from the third electrode C and moves to the second stator 2b.
Sucked on the side.

The above-described series of sequences, that is, FIG.
As shown in (a) to (d), a voltage is sequentially applied to the electrode A, the electrode D, the electrode B, the electrode D, the electrode C, and the electrode D, and the sequence of applying the voltage to the electrode A is sequentially repeated again. The mover 3 microscopically vibrates vertically in a direction intersecting the arrow 24, and macroscopically, the arrangement direction (forward direction 2) of the electrodes arranged on the first stator 2a.
In 4), it is finely driven linearly.

In the above-described sequence, the case where the mover 3 is moved in the forward direction 24 has been described.
When the mover 3 is moved in the backward direction opposite to the forward direction 24, the voltages are applied to the electrodes in the reverse order as described above. That is, first, in a state where the first movable element electrode portion 3a and the electrode D are maintained at the low level potential L as shown in FIG. 2D, the electrode C is applied to the electrode C as shown in FIG. A voltage is applied. Therefore, the electrode C and the electrode portion 3
a due to the electrostatic force between the electrodes 3, i.e., the Coulomb force.
The mover 3 is attracted to the first stator 2a side so that a is drawn to the electrode C. Subsequently, the switching circuit 40 switches from the third electrode C to the electrode D, and a voltage is applied to the electrode D as shown in FIG. 2 is sucked toward the stator 2b.

Thereafter, switching is performed from the electrode D to the stator electrode B by the switching circuit 40, and a voltage is applied to the stator electrode B as shown in FIG.
The movable element 3 is attracted to the first stator 2a by the electrostatic force between the movable element 3 and the first movable element electrode 3a. continue,
The voltage is applied to the electrode D as shown in FIG. 2D by switching from the electrode B to the electrode D by the switching circuit 40, and the mover 3 is separated from the stator electrode B and moves to the second stator 2b side. It is sucked.

Further, the electrode is switched from the electrode D to the electrode A by the switching circuit 40, a voltage is applied to the electrode A as shown in FIG. 2A, and the movable member is moved by the electrostatic force between the electrode A and the electrode portion 3a. The child 3 is sucked toward the first stator 2a. Subsequently, the electrode is switched from the electrode A to the electrode D by the switching circuit 40, and a voltage is applied to the electrode D as shown in FIG. 2D, and the mover 3 is separated from the third electrode C and fixed to the second fixed position. The child 2b is sucked.

In the sequence of the movement of the mover 3 in the backward direction, a voltage is sequentially applied to the electrode C, the electrode D, the stator electrode B, the electrode D, the electrode A, and the electrode D. When the sequence of the voltage application is sequentially repeated, the mover 3 is arranged macroscopically on the first stator 2 a while vertically vibrating in a direction crossing the arrow 24. Electrode arrangement direction (forward direction 24
(In the direction opposite to the above direction).

According to this configuration, there is no need to perform positioning for disposing the phases of the electrodes provided on the first stator 2a and the second stator 2b so as to be shifted by a predetermined amount. In addition, it is possible to improve mass productivity.

Next, another method of driving the mover 3 in this embodiment will be described.

FIG. 3 shows another method of applying a voltage to the electrodes A to D of the stators 2a and 2b using the configuration of the electrostatic actuator shown in FIG. 1 and the movement of the mover 3 at that time. It is shown. In this method, the voltage is changed from electrode A → electrode D →
Electrodes A + B → electrode D → electrode B → electrode D → electrode B + C → electrode D → electrode C + A → electrode A... Are sequentially and repeatedly applied so that the mover 3 microscopically vibrates up and down while macroscopically. Is driven in the arrangement direction (the right side in the figure) of the electrodes arranged on the first stator.

Here, among the electrodes provided on the first stator 2a, first, the movable element 3 is sucked by one system of electrodes (for example, A), and then the movable element 3 is sucked by two systems of electrodes (for example, A + B). By sucking the electrode 3, the electrode portion 3a of the mover 3 receives an acting force so as to be substantially at the center of the two systems of electrodes to which a voltage is applied. According to such a driving method, since the acting force for driving the mover 3 in the vertical direction can be relatively large, the mover can be driven more smoothly.

The driving operation of the electrostatic actuator shown in FIGS. 3 (a) to 3 (e) is specifically described in FIGS. 4 (a) to 4 (e).
Is achieved by applying the voltage signal shown in FIG.

First, the first mover electrode portion 3a and the electrode D are maintained at the low level potential L as shown in FIGS. 4 (e) and 4 (d). A voltage is applied to A. Therefore, as shown in FIG. 3A, the movable element 3 is moved so that the first movable element electrode section 3a is attracted to the electrode A by the electrostatic force between the electrode A and the electrode section 3a.
It is sucked to the first stator 2a side. Subsequently, FIG.
As shown in FIG.
Is switched to the electrode D, and the voltage is applied to the electrode D.
As shown in FIG. 3B, the mover 3 is separated from the electrode C and is sucked toward the second stator 2b.

Thereafter, the switching circuit 40 switches from the electrode D to the electrodes A and B, and a voltage is applied to the stator electrodes A and B as shown in FIGS. The movable element 3 is attracted to the first stator 2a side by the electrostatic force between the movable element 3 and the first movable element electrode section 3a, as shown in FIG. 4C. Here, since a voltage is applied to both of the electrodes A and B as shown in FIGS. 4A and 4B, as shown in FIG. The mover 3 is attracted to the first stator 2a side so as to face both A and B. continue,
The electrodes are switched from the electrodes A and B to the electrode D by the switching circuit 40, and a voltage is applied to the electrode D as shown in FIG. 4D, and as shown in FIG. B and is sucked toward the second stator 2b.

Thereafter, the electrode is switched from the electrode D to the electrode B by the switching circuit 40, and a voltage is applied to the electrode B as shown in FIG. The movable element 3 is attracted to the first stator 2a side as shown in FIG.
Subsequently, switching is performed from the stator electrode B to the electrode D by the switching circuit 40, and a voltage is applied to the electrode D as shown in FIG. Is attracted to the stator 2b side.

Further, the electrode D is switched to the electrodes B and C by the switching circuit 40, and a voltage is applied to the electrodes B and C as shown in FIGS. 4 (b) and 4 (c).
The mover 3 is attracted toward the stator 2a by the electrostatic force between the electrodes B and C and the mover electrode 3a. here,
Since a voltage is applied to both the electrodes B and C, the mover 3 is attracted to the first stator 2a side so that the mover electrode portion 3a faces both the electrodes B and C. You. Subsequently, switching is performed from the stator electrodes B and C to the electrode D by the switching circuit 40, and a voltage is applied to the electrode D as shown in FIG. 4D, and the mover 3 is separated from the electrodes B and C. It is sucked toward the second stator 2b.

After that, the electrode is switched from the electrode D to the electrode C by the switching circuit 40, a voltage is applied to the electrode C as shown in FIG. 4 (c), and an electrostatic force between the electrode C and the movable electrode 3a. Thereby, the mover 3 is attracted to the first stator 2a side. Subsequently, the switching circuit 40
The electrode C is switched to the electrode D by means of FIG.
A voltage is applied to the electrode D as shown in FIG.
Is attracted to the second stator 2b side away from the stator electrode B.

Thereafter, the switching circuit 40 switches from the electrode D to the electrodes C and A, and FIG.
As shown in (a), a voltage is applied to the electrodes C and A,
The movable element 3 is attracted to the first stator 2a side by the electrostatic force between the electrodes C and A and the movable element electrode section 3a. Here, since a voltage is applied to both the electrodes C and A, the first mover electrode portion 3a is moved to the first fixed position so that the mover 3 is opposed to both the electrodes C and A. The child 2a is sucked. Subsequently, the electrodes are switched from the electrodes C and A to the electrode D by the switching circuit 40, and a voltage is applied to the electrode D as shown in FIG. 4D, and the mover 3 moves away from the stator electrodes B and C. It is sucked toward the second stator 2b.

Again, as described above, as shown in FIG. 4A, a voltage is applied to the electrode A, and the movable element 3 is moved by the electrostatic force between the electrode A and the first movable element electrode section 3a. Is sucked toward the first stator 2a.

As described above, the voltage is applied to the electrodes A, D,
Both electrodes A and B, electrode D, stator electrode B, electrode D, both stator electrodes B and C, electrode D, third electrode C, electrode D, both third and first electrodes, electrode D , And the electrodes A are sequentially applied, so that the mover 3 microscopically vibrates vertically while the first stator 3 macroscopically.
It is driven in the arrangement direction (forward direction) of the electrodes arranged in a.

In this embodiment, the first stator 2a is provided with three electrodes, but the present invention is not limited to this case. For example, as shown in FIG.
May be provided with four systems of electrodes A to D (first electrodes), and the second stator 2b may be provided with one system of electrodes E (second electrodes). The movable element 3 may be provided with an electrode F (third electrode), and the movable element 3 may be driven in a predetermined direction by sequentially applying a voltage to the electrodes of the stators 2a and 2b. At this time, the order of applying the voltage is, for example, electrode A → electrode E → electrode B → electrode E → electrode C → electrode E → electrode D → electrode E → electrode A ... or electrode A + B → electrode E → electrode B +
C → electrode E → electrode C + D → electrode E → electrode A + B. With such a configuration, the same operation and effect as the above-described embodiment can be obtained.

The operation of the electrostatic actuator shown in FIG. 5 will be described in more detail with reference to FIGS. 6 and 7. In the electrostatic actuator shown in FIG. 5, a fourth electrode D is further provided on the first stator 2a of the electrostatic actuator shown in FIG. 2 in addition to the first to third electrodes A, B, and C. ing. The first to fourth electrodes A, B, C, and D are arranged at the same pitch, and the mover 3 includes a plurality of mover electrode portions 3a having a width corresponding to the width of two stator electrodes. They are arranged along the forward direction. The mover 3 forms one system of electrodes F maintained at the same potential. On the surface of the stator 2 b facing the mover 3, a uniform planar electrode E is provided over the movable range of the mover 3.

As shown in FIG. 6, four electrodes A, B,
The electrodes C, D and the electrode E are connected to a voltage source 42 that generates a voltage via a switching circuit 40 that determines the timing of applying a voltage to the electrodes A, B, C, D, and the electrode E. The electrode F of the mover 3 is grounded via this switching circuit 40 or is connected to a negative potential. The switching circuit 40 includes electrodes A,
Fixed contacts 40A, 4B connected to B, C, D and electrode E;
0B, 40C, 40D and grounded fixed contact 40G
And these fixed contacts 40A, 40B, 40C, 40
A first movable contact 40F connected to a voltage source 42 connected to D and a second movable contact 40E grounded or connected to a negative potential. In this switching circuit 40, these fixed contacts 40A, 40B, 4
When one of OCC and 40D is connected to voltage source 42 via first movable contact 40F, the other fixed contacts 40A and 40D
0B, 40C, and 40D are grounded via the second movable contact 40E, or are connected to the negative potential L.

In this electrostatic actuator, a voltage is applied to the electrodes A, E, B, E, C, E, D, and E in this order as in the other embodiments, and the electrodes are again turned on. A is applied to the mover 3
Macroscopically vertically vibrates in a direction intersecting with the forward direction 24, and macroscopically linearly and minutely in the arrangement direction (forward direction 24) of the electrodes arranged on the first stator 2a. Driven.

In the actuator mechanism shown in FIG. 6, the voltage at the timing shown in FIGS. 7A to 7F is applied to the fixed contacts 40A, 40B, 40C, and 40D to move the movable element 3 forward. It can be finely driven linearly in the direction or backward direction. That is, first, the electrode F of the first mover electrode portion 3a is maintained at the low-level potential L as shown in FIG. 7 (f), and the electrodes A, as shown in FIGS. 7 (a) and 7 (b). A voltage is applied to B. Therefore, the electrodes A and B and the stator electrode portion 3a
Of the mover electrode 3a due to the electrostatic force between the electrodes A and B
The mover 3 is moved to the first stator 2a
Sucked on the side. Subsequently, as shown in FIG. 7E, the switching circuit 40 switches from the electrodes A and B to the electrode E, and a voltage is applied to the electrode E.
The air is sucked toward the second stator 2b away from the third electrodes A and B.

Thereafter, switching from the electrode E to the stator electrodes B and C is performed by the switching circuit 40, and FIG.
And (c), a voltage is applied to the stator electrodes B and C, and the movable element 3 is moved to the first position by the electrostatic force between the electrodes B and C and the first movable element electrode section 3a. It is sucked toward the stator 2a. Subsequently, the switching from the stator electrodes B and C to the electrode E is performed by the switching circuit 40, and FIG.
A voltage is applied to the electrode E as shown in FIG.
Is attracted to the second stator 2b side away from the electrodes B and C.

After that, the electrode E is switched to the electrodes C and D by the switching circuit 40, and a voltage is applied to the electrodes C and D as shown in FIGS. 7 (c) and 7 (d).
The movable element 3 is attracted to the first stator 2a side by the electrostatic force between the electrodes C and D and the first movable element electrode section 3a. Subsequently, the electrodes C and D are switched by the switching circuit 40.
To the electrode E, and a voltage is applied to the electrode E as shown in FIG.
From the second stator 2b.

Further, switching from the electrode E to the electrodes D and A is performed by the switching circuit 40, and a voltage is applied to the electrodes D and A as shown in FIGS. 7 (d) and 7 (a).
The movable element 3 is attracted to the first stator 2a by electrostatic force between the electrodes D and A and the movable element electrode section 3a. Subsequently, the stator electrodes D and A are switched by the switching circuit 40.
7E, the voltage is applied to the electrode E, and the mover 3 is separated from the stator electrodes D and A and is attracted to the second stator 2b side. .

In the electrostatic actuator shown in FIG. 5, the voltage is applied to the electrode A, the electrode E, both of the electrodes A and B, and the electrodes E and E in the same manner as described with reference to FIGS. Electrode B, electrode E, both electrodes B and C, electrode E, electrode C, electrode E, both electrodes C and D, electrode E, electrode D, electrode E, both electrodes D and A, electrode E, and electrode The voltages may be sequentially applied in the order of A. As a result, the movable element 3 is microscopically driven while vertically vibrating, and is macroscopically driven in the arrangement direction (forward direction 24) of the electrodes arranged on the first stator 3a.

The driving force for operating the electrostatic actuator will be briefly described below with reference to FIG. In the following description, a case where four electrodes A, B, C, and D are provided is described. However, the number is not limited to four, and a stator provided with three stator electrodes or n stators is provided. The same driving force is applied to the mover 2 even when it is applied to the mover 3 from the stator electrode provided with the electrode.

The driving force, that is, the generated force (here, the vertical direction is represented by Fz and the horizontal direction (traveling direction) is represented by Fy) is determined by each electrode A provided on the electrode portion 3a of the mover 2 and the stator 3. , B,
Assuming that C and D are both parallel plate conductor electrodes having no thickness, they are expressed by the following equations (Equation 1) and (Equation 2).

[0065]

(Equation 1)

Here, n is the number of the mover electrode portions 3a provided on the mover 3. ε is the dielectric constant between the electrodes A, B, C, D provided on the mover 3 and the stator 2a. The dielectric constant is
It is expressed by a product of a vacuum dielectric constant and a relative dielectric constant of a substance between the electrodes A, B, C, and D provided on the mover electrode portion 3a of the mover 3 and the stator 2a. The dielectric constant of vacuum is ε0 = 8.85 × 10
^-12 [N / m], and the relative dielectric constant is, for example, about 1 for air and about 3 for polyimide used for insulating electrodes and the like. S is the area of the opposing portions of the movable plate electrode portion 3a and the parallel plates formed by the electrodes A, B, C, and D, which face each other and constitute the parallel plate. Now, as shown in FIG. 6, assuming that the width of the facing electrode portion (a side along the forward direction is a width) is w and the depth is L, there is a relationship of S = w × L. V represents a voltage applied between the electrodes. D represents the distance between the electrodes, and the distance d is
In FIG. 6, it corresponds to GapGa.

In a state where a voltage is applied to the electrodes C and D and the electrodes C and D are active, the above (Equation 1) and (Equation 2) will be considered. Here, the edge of the electrode C in the backward direction, that is, the left end is defined as a reference position, this is defined as the origin (0), the forward direction is defined as plus, and the backward direction is defined as minus. Mover electrode section 3a
Is located on the left side of the left end of the electrode C,
That is, when the displacement X is -L or more, the movable electrode portion 3a and the electrode C do not overlap each other and do not constitute parallel flat plates facing each other. To zero.

On the other hand, as shown in FIG. 6, when the left end of the mover 3 is within the range from the negative L width to the origin (0) with respect to the left end of the electrode C, that is, the displacement X is changed from -L to 0. In the case of, the generated force Fy in the horizontal direction is constant regardless of the position of the mover 3. This is (Equation 2)
Has no horizontal component. Further, when the left end of the mover 3 is within a range from the origin (0) to the plus side to the width L with respect to the electrode C, that is, when the displacement X is 0 to + L or less, The magnitude of the generated force is constant in the minus direction. This is because the depth direction of the mover 3 affects the generated force, that is, the tapered portion of the side surface of the mover electrode portion 3a as shown in FIG. This is because the influence of the mutual action between A, B, C, and D is ignored. In an actual actuator mechanism, it is necessary to consider those influences, but in the above description, it is ignored for the sake of simplicity.

FIG. 8 is a graph showing the generated force Fy in the horizontal direction based on the above consideration. This graph shows the mover 3 using the finite element method.
3 shows changes in the generated force due to the positional relationship between the electrodes A, B, C, and D provided on the stator 2a. The vertical axis represents the generated force Fy in the horizontal direction with the forward direction being plus, expressed in force (unit [N]), and the horizontal axis represents the electrodes A, B, C, D provided on the mover 3 and the stator 2a. , Ie, a displacement value with the forward direction being plus. This graph takes the gap Ga shown in FIG. 6 as a parameter, and the graph shows that the gap Ga is 7.8.
In the case of microns, the graph shows that the gap Ga is 5.8.
In the case of microns, the graph shows that the gap Ga is 4.8.
In the case of microns, the graph shows that the gap Ga is 3.8.
The case of microns is shown. The size of the electrostatic actuator for obtaining the graph of FIG. 8 is determined on the assumption that the size is applied to a mobile device such as a mobile phone. For example, Gap is 3.8 μm to 7.8 μm, and L is 2 μm.
8 μm, w: 12 μm, Ph: 16 μm, mover 3
The number of the mover electrode portions 3a provided in is set to 94.

As is clear from the graph of FIG. 8, the generated force Fy in the horizontal direction gradually changes before and after the mover electrode portion 3a of the mover 3 overlaps with the electrode C and before and after the mover electrode portion 3a separates. As is clear from the graph, the generated force Fy in the horizontal direction can be replaced with a sinusoidal waveform connecting the zero point and the maximum value. In FIG. 8, the voltage applied to the stator electrode is a value calculated at 100 V. According to the graph shown in FIG. 8 and the results considered from this graph, Gap is preferably in the range of 3 to 10 μm, more preferably in the range of 3 to 5 μm. It has been found that Fy can be provided to the mover 3.

[Second Embodiment] A second embodiment of the electrostatic actuator according to the present invention will be described with reference to FIG. 9 and FIG. Note that the same portions as those shown in FIG. 1 are denoted by the same reference numerals, and redundant description will be omitted (hereinafter, the same applies to the description of each drawing).

FIG. 9 is a diagram showing a schematic configuration of the electrostatic actuator according to the present embodiment.

Here, the electrode width (L) of the electrode portion 3a of the mover 3 is equal to the electrode width (W) of each electrode provided on the stator 2a.
It is 1.5 to 2.5 times, preferably 1.5 to 2.0 times of a).

As shown in the figure, when a voltage is applied to the electrodes A and B, the mover 3 is attracted to the stator 2a side, and the electrodes A and B and the electrode portion 3a of the mover 3 overlap. Acting force works. Subsequently, when a voltage is applied to the electrode D, the mover 3 is attracted to the stator 2b side. Further, when a voltage is applied to the electrodes B and C, the mover 3 is attracted to the stator 2a side in the same manner as when a voltage is applied to the electrodes A and B,
The electrode portion 3a of the mover 3 receives an acting force so as to overlap the electrodes B and C. Thus, the voltage is applied to the electrode A + B → electrode D → electrode B + C → electrode D → electrode C + A → electrode D → electrode A
+ B... Are sequentially and repeatedly applied.
Is vertically driven in a microscopic manner, and is macroscopically driven in the arrangement direction of the electrodes arranged on the first stator (right side in the figure). Also, reverse the order of applying the voltage (electrode A + B →
(Electrode D → electrode A + C → electrode D → electrode C + B → electrode D → electrode A + B...), The movable element 3 is macroscopically driven in the direction opposite to the above-mentioned direction (left side in the figure).

Here, the electrode width (L) of the electrode portion 3a provided on the mover 3 is 1.5 to 2.5 times, preferably 1.5 to 2.0 times the electrode width (a) of each electrode provided on the stator 2a. The reason for setting the double will be described with reference to FIG. As shown in FIG. 10A on the upper side, for example, when a voltage is applied to the electrodes B and C, the moving direction of the mover 3 is also opposite to the original traveling direction (right side in the figure) (left side in the figure). Acting force is generated. Accordingly, in order to reduce the acting force in the opposite direction, as shown in FIG.
Should be smaller. However, if the electrode width is too small, the total electrode area becomes small, the acting force for driving the mover 3 in the vertical direction is reduced, and the voltage of the stator 2a is reduced by the electrode portion 3a provided on the mover 3. There is a demerit that the positioning force for positioning the two electrodes being applied almost in the middle is unstable. Therefore, as a result of conducting an electromagnetic field analysis in consideration of these factors, it was found that the electrode width (L) of the electrode E of the mover is preferably in the above range.

[Third Embodiment] A third embodiment of the electrostatic actuator according to the present invention will be described with reference to FIGS.

For example, as shown in FIG.
When a voltage is applied to the electrode A of the mover 3, the electric field generated between the electrode E of the mover 3 and the electrode A of the stator 2a causes
Receives electrostatic force (Coulomb force) and is attracted to the stator 2a side. At this time, if the electrode A and the electrode portion 3a of the mover 3 are in direct contact with each other, an electrical short circuit occurs, and a phenomenon occurs in which the electrode is instantaneously destroyed. Therefore, a dielectric film 4 having a sufficient dielectric breakdown strength is provided between the electrode A and the electrode portion 3a. However,
As described above, in the conventional voltage applying method, for example, the dielectric film 4 provided in the vicinity of the electrode A on the stator 2a side causes dielectric polarization 5, and when viewed macroscopically, the surface of the stator 2a Act on the mover 3a as if it had the potential of Therefore, even when the control is shifted to the next drive sequence, a phenomenon that the mover 3 is not properly driven toward the stator 2b having the electrode D may occur. this is,
This is the effect of the electrical bias generated in the dielectric film 4 due to the dielectric polarization 5. Although the potential remaining due to the dielectric polarization 5 is small, the Coulomb force is inversely proportional to the square of the distance between the electrodes. Therefore, once the electrode E is attracted to the electrode A and the distance between the electrodes is reduced, the residual potential remains. Even if the potential is small, the acting force exerted on the mover 3 is large. The present invention realizes a drive sequence that reduces the adverse effects described above and drives the mover 3 satisfactorily.

In the present embodiment, when a voltage is applied to the electrode D from the state in which the mover 3 is pulled by the electrode A, the electrode A of the stator 2a is applied to the electrode A of the stator 2a. By giving a potential difference so as to be lower than the potential of E (the potential of the electrode A is minus potential when the potential level of the mover 3 is set to zero), the exfoliation of the mover 3 from the stator 2a is improved, This realizes a smooth actuator operation. This is a macroscopic view of the stator 2a
Between the electrode A of the movable element 3 and the corresponding electrode E of the mover 3, the electric field caused by the bias of the electric charge due to the dielectric polarization 5 remaining in the dielectric film 4, and the electric potential newly applied to the electrode A (from the electric potential level of the electrode E). It can be explained that the electric field generated between the electrode E and the electrode E is an electric field in the opposite direction, and both of them cancel each other out. When viewed microscopically, the bias of the charges caused by the dielectric polarization 5 remaining in the dielectric film 4 is eliminated by the electric field due to the newly applied potential to the electrode A (lower than the potential level of the electrode E). Can be explained.

In order to operate the actuator mechanism as shown in FIGS. 11A and 11B, a voltage signal as shown in FIGS.
Is applied to each electrode. Here, FIG.
(B) and (c) show timing charts of signal voltages applied to the electrodes A, B and C, respectively, and FIG.
Shows a timing chart of a signal voltage applied to the stator electrode D, and FIG. 12E shows a voltage applied to the mover electrode E. The voltage applied to the mover electrode E shown in FIG. 12E is the ground potential, and the low level L of the signal voltage applied to the stator electrode D shown in FIG. On the other hand, the high level H has a high potential. FIG. 12 (a),
The high level H of the signal voltage applied to the electrodes A, B, and C shown in (b) and (c) is a high potential,
The low level L is set to a negative potential, and the intermediate level is a ground potential. Therefore, FIG.
At a high level H shown in (a), (b), and (c), the mover electrode section 3a is attracted to the electrodes A, B, and C by a suction force, and at a low level L, the mover electrode section 3a is moved to the electrode A,
B and C are separated by repulsive force. Then, at the intermediate level, the mover electrode section 3a does not receive any action from the electrodes A, B, and C.

The movable element electrode portion 3a may be in a so-called floating state, that is, in a floating state in which the potential is not electrically grounded. Further, a dummy electrode grounded may be provided in the vicinity of the mover 3 so that the electrostatic attraction force to the mover electrode portion 3a works effectively. Further, in the embodiment shown in FIGS. 11A and 11B, a dielectric film is provided on the stator 2a side, but as shown in FIGS. 13A and 13B. The dielectric film 4 may be provided on the mover 3 side. Similarly, the actuators shown in FIGS. 13A and 13B are operated by applying voltage signals as shown in FIGS. 12A to 12F from the switching circuit 40 to each electrode.

[Fourth Embodiment] A fourth embodiment of the electrostatic actuator according to the present invention will be described with reference to FIGS.

The electrostatic actuator according to the present embodiment
The shape of the mover 3 is characteristic. As shown in FIG. 14, the electrode portions 6 are provided at a constant pitch on a portion of the surface of the mover 3 facing the electrode portion provided on the stator. Also, at least one lens surface (optical element surface) 7 that satisfies necessary optical characteristics is provided on a surface perpendicular to the driving direction of the electrostatic actuator when viewed macroscopically. In FIG. 14, the lens surface 7 is located on the upper side of the drawing. In addition, a lens surface may be provided on the lower side opposite to the upper lens surface 7 which is hidden in the drawing. The mover 3 including the lens surface 7 and the electrode portion 6 constituting the electrostatic actuator is manufactured by, for example, glass molding technology.
That is, the lens surface 7 is integral with the mover 3, and one surface of the mover 3 forms a lens surface.

How the electrode section 6 is manufactured so as to be driven as an electrostatic actuator will be described with reference to FIG. First, a mover shape as shown in FIG. 15 is manufactured by glass molding technology or the like. Next, the mover 3 is installed with the lens surface 7 facing upward. After the installation surface is brought into contact with a jig such as a metal plate and fixed, the mover 3 is coated with a conductive material. Sputtering, vapor deposition, and coating are used as a method of coating. As a result, the conductive film is formed on the other five surfaces except for one surface in contact with the jig or the like. Subsequently, the resist is applied in the same posture by using a resist applying method (spray method) utilizing electrostatic attraction. As a result, a resist film is formed on the other five surfaces except for one surface that has come into contact with the jig or the like. Here, the mover 3 is detached from the jig or the like, and the mover is attached to the electrode patterning jig. The jig for electrode patterning has a hole for accommodating the mover, and the depth of the hole is set so that the surface on which the electrode is provided and the surface of the jig for electrode patterning are approximately the same height. (Not shown). The mover is firmly fixed to the electrode patterning jig by a mechanical pressing method such as a spring or the like or a suction method using negative pressure. The jig for electrode patterning includes a movable element 3
May be attached at one time (for that purpose,
Provide multiple holes). Subsequently, pattern transfer (a so-called photo fabrication technique) using a photo transfer method is performed on the surface on which the resist is applied, and a resist exposure step is performed. Subsequently, a necessary portion is patterned with a conductive material through etching of a resist portion and etching of a metal portion. At this time, the conductive material may be transparent (for example, a material such as ITO is used) or non-transparent. If it is transparent, the mover is completed in the above steps. If it is non-transparent, before the etching step, the mover is once removed from the jig for electrode patterning in the above-described step, and the movable element is placed on the jig for electrode patterning again with the lens surface facing upward. Subsequently, using an optical mask (generally called a reticle in a semiconductor process) for removing the conductive material only on the lens surface, pattern transfer using a photo transfer method (so-called photo fabrication technology) is performed, and a resist exposure process is performed. Is carried out. Thereafter, the mover 3 is completed by etching the resist portion and the metal portion in the same manner as described above.

In the electrode section 6 of the mover 3, all the electrodes on the four side surfaces, including the portion where the ladder-shaped patterning is performed, are electrically connected via the side of the lens surface. In order to obtain the same effect as that of providing the ladder-shaped electrode portion 6, an uneven shape (the pitch is assumed to be the same as that of the ladder-shaped electrode) is provided on the surface thereof, and the entire surface is made of a conductive material. It can be coated.

Further, a region 8 where no ladder-like electrode is provided is provided on a part of the surface on which the ladder-like electrode portion 6 is provided so that the mover 3 does not directly contact the electrode provided on the stator. It doesn't matter. As shown in FIGS. 16A and 16B, a stopper 10 having a minute height (however, higher than the thickness of the provided electrode) is provided on the surface of the stator electrode corresponding to the region 8. If the stopper 10 and the region 8 slide, it is possible to prevent the electrode portion of the mover from coming into contact with the electrode of the stator. Note that FIGS. 17A and 17B
As shown in (1), a stopper 10 for preventing contact may be provided on the mover 3 side.

By manufacturing the mover by the manufacturing method described above, it is possible to realize an inexpensive electrostatic actuator which is rich in mass productivity and inexpensive.

[Fifth Embodiment] A fifth embodiment of the electrostatic actuator according to the present invention will be described with reference to FIG.

FIG. 18 shows a method of configuring the electrostatic actuator according to the present embodiment. The stator 2 includes at least two divided parts 2c and 2d. For example, when divided into two, one is provided with three systems of electrodes and the other is provided with one system of uniform electrodes. By mechanically pressing the two divided parts 2c and 2d and bonding the side surfaces and the like, the stator 2 having an inter-electrode distance having a gap larger than the mover 3 by a certain distance is manufactured. . At that time, the mover 3 is inserted in advance in advance and 2
By bonding the two divided parts, an electrostatic actuator is completed. In addition, the stator 2 with high accuracy
Is realized, for example, by molding. The stator 2 is divided so that the direction processed by punching or pressing is uniaxial, and a highly accurate inter-electrode distance is realized. In FIG. 18, the stator 2c provided with the uniform electrode D is a molded part, but the stator provided with three types of electrodes may be replaced with the molded part.

[Sixth Embodiment] A sixth embodiment of the electrostatic actuator according to the present invention will be described with reference to FIGS. This embodiment relates to a structure of a stator constituting an electrostatic actuator according to the present invention.

FIG. 19 shows the structure of the stator 2 and the electrodes A to
FIG. 3 shows a take-out form of C, and is a plan view of a substrate 11 constituting a stator 2 and its AA cross-sectional view and BB cross-sectional view. Three electrodes A to C are formed on a surface of the stator substrate 11 facing a movable element (not shown). As the substrate 11, glass or a silicon substrate having a surface on which an insulating film such as a silicon oxide film is formed is used. Here, three lines of electrodes are illustrated for four stages. The electrodes A and C are arranged so as to mesh with each other in a comb shape. The electrode B is arranged between the electrode A and the electrode C, and the wiring from the B electrode is taken out of the wiring of the electrode A via an insulating film provided on the wiring from the electrode A. Each wiring is taken out from the surface side on which each electrode is formed.

Next, the manufacturing process of the stator will be described with reference to FIG.

First, an electrode A and a wiring portion, an electrode C and a wiring portion, and an electrode B and a wiring portion of an electrode B located outside the wiring portion of the electrode A are formed of a metal material 12 such as Al on the substrate 11. (See FIG. 20A). An insulating film 13 is formed thereon, and a through-hole 14 for connecting the wiring portion of the B electrode located outside the wiring portion of the electrode A and the B electrode is formed on the B electrode located outside the wiring portion of the A electrode. (See FIG. 20 (b)). As the insulating film, silicon oxide, silicon nitride, polyimide, or the like can be used depending on the process. Next, the wiring 15 connecting the electrode B and the wiring part of the electrode B located outside the wiring part of the electrode A is formed (FIG. 20C).
reference). Further, if necessary, an insulating film 16 is formed on the wiring 15 connecting the B electrode and the wiring part of the B electrode located outside the wiring part of the electrode A (see FIG. 20D).

Here, the wiring connecting the electrode B and the electrode B is formed above the wiring of the electrode A, but may be formed below the wiring of the electrode A. Further, here, a wiring for connecting the wiring portion of the electrode B and the electrode B is formed on the insulating film, but wire bonding may be performed.

Here, the substrate 11 constituting the stator is
Although the case where three types of electrodes are formed has been described above,
The present invention is not limited to this case. For example, four electrodes A to D may be provided on the substrate 11 as shown in FIG.

[Seventh Embodiment] A seventh embodiment of the electrostatic actuator according to the present invention will be described with reference to FIG. This embodiment also relates to the structure of the stator constituting the electrostatic actuator according to the present invention.

FIG. 22 shows the structure of the stator 2 and the electrodes A to
FIG. 3 shows a take-out form of C, and is a plan view of a substrate 11 constituting a stator 2 and its AA cross-sectional view and BB cross-sectional view. The difference from the sixth embodiment described above is that each wiring is not formed on the surface on which each electrode is formed, but on the substrate 11.
Is taken out from the back surface of As shown in the figure,
A through hole 17 is provided at a portion corresponding to the wiring take-out portion.
Is opened, and the wiring is taken out on the back surface of the substrate.

[Eighth Embodiment] An eighth embodiment of the electrostatic actuator according to the present invention will be described with reference to FIG. This embodiment also relates to the structure of the stator constituting the electrostatic actuator according to the present invention.

FIG. 23 shows the structure of the stator 2 and the electrodes A to
FIG. 4 shows a take-out form of C, and is a plan view, a cross-sectional view taken along line AA and a cross-sectional view taken along line BB of a substrate 11 constituting a stator 2, and a rear view of the substrate 11. The feature of this embodiment is that each electrode is taken out on the back surface of the substrate before being connected. Electrodes are formed on the surface of the substrate 11 facing the mover, and wires for connecting the electrodes are formed on the back surface of the substrate, and both are connected via the through holes 18.

[Ninth Embodiment] A ninth embodiment of the electrostatic actuator according to the present invention will be described with reference to FIGS. This embodiment also relates to the structure of the stator constituting the electrostatic actuator according to the present invention.

FIGS. 24 and 25 show the structure of the stator 2 and the manner in which the electrodes A to C are taken out. FIGS. 24 and 25 are plan views of substrates 11a and 11b constituting a part of the stator 2, respectively. A sectional view, BB sectional view, and substrate 11
It is a rear view of a and 11b. The feature of this embodiment resides in that a bonded substrate to which the substrate 11 having the wirings shown in FIGS. 24 and 25 is bonded is used. Structurally,
As shown in FIG. 26, the substrate 11a having the electrodes shown in FIG. 24 and the substrate 11b having the through holes shown in FIG. 25 are bonded together and integrated.

Next, the working process of this embodiment will be described. First, wires and through holes for connecting the respective electrodes are formed on the back side of the substrate 11a in the same manner as in the above-described eighth embodiment. However, since this surface is a surface to be joined to the substrate 11b, the wiring portion is formed in a recess processed in advance as shown in the figure. Further, the through hole does not need to penetrate, and may have a depth penetrating when polished in a later step.
Next, the substrate 11a and the substrate 11b are joined. The bonding of the substrates can be performed by a method according to the type of the substrate, such as an anodic bonding method in the case of silicon and glass and a water glass method in the case of silicon. A through hole or a wiring for taking out a wiring may be formed in advance on the substrate 11b to be joined. In the bonded substrate 11, the substrate 11a side is thinned to a predetermined thickness by polishing. At this time, it is necessary that the through hole penetrates. Next, each electrode and wiring are formed on the polished surface of the substrate 11a, and are connected to the wiring on the back surface side of the substrate 11a. Further, if through holes and wires for taking out wires are not formed in advance on the substrate 11b side, these are formed, and the substrates 11a and 11
The stator 2 is completed by connecting the wiring b. By using this method, there is an advantage in the process that the depth processing of the through hole provided in the substrate 11a can be small. In the processing of through holes, generally, isotropic processing (that is, if processing is performed in a certain depth direction, the processing is performed in the horizontal direction by the same amount). . In that case, the hole diameter (φ) of the through-hole that can be opened is restricted by the thickness of the substrate through which the through-hole is to be penetrated, and a limit is imposed when the through-holes come close to each other. This restriction hinders a fine arrangement pitch of the electrodes corresponding to the electrodes of the mover provided on the surface of the substrate 11a. By using the method of the present embodiment, a remarkable effect of being able to cope with miniaturization of the surface electrode of the substrate 11 can be expected. In the present description, the wiring of the surface electrode provided on the front surface of the substrate 11a is provided on the back surface of the substrate 11a, but this wiring portion may be provided on the surface of the substrate 11b.

[Tenth Embodiment] A tenth embodiment of the electrostatic actuator according to the present invention will be described with reference to FIG. This embodiment also relates to the structure of the stator constituting the electrostatic actuator according to the present invention.

FIG. 27 shows the structure of the stator 2 and the electrodes A to
FIG. 3 shows a take-out form of C, a plan view of a substrate 11 constituting the stator 2, a cross-sectional view taken along line AA of FIG.
FIG. 3 is a cross-sectional view of B and a rear view of the substrate 11.

This embodiment is characterized in that the substrate 11 of the stator 2
Is that an SOI substrate is used for each, and each electrode is made of bulk silicon. On one surface of the SOI substrate 11, a silicon structure 19 serving as each electrode is formed using a DRIE device or the like. An insulating film may be formed on the surface of the silicon structure.

A through hole 20 for taking out an electrode is formed on the back surface of the substrate, and connection with a silicon structure to be an electrode and wiring are taken out.

Next, a modification of this embodiment will be described. The structure of this modification is almost the same as that shown in FIG. 27, and differs in that each electrode is replaced with Ni instead of a silicon structure.

The manufacturing process of this modification will be described. First, a metal layer serving as a seed layer for plating is formed on an oxidized silicon substrate. On the substrate, an exposure and development process of a thick film resist is performed to form a mold structure for forming an electrode structure. Next, a Ni layer serving as an electrode structure is formed by electroplating. After that, the thick film resist layer is removed, and an insulating film is coated to complete the electrode structure. In this manufacturing process, an adjusting process (for example, polishing) is performed as necessary. A through hole for taking out an electrode is formed on the back surface of the substrate in the same manner as in the present embodiment, so that connection to the electrode structure and wiring are taken out.

[Eleventh Embodiment] Referring to FIG.
An application example using the electrostatic actuator according to the present invention will be described.

The electrostatic actuator according to the present invention is suitable for use as a focus adjusting mechanism of a small camera because of its excellent driving characteristics.

FIG. 28 shows a module portion of a small camera on which the electrostatic actuator according to the present invention is mounted. An image sensor such as a CMOS or a CCD is provided on a substrate 21 and an electrostatic actuator is provided thereon. 22 are provided. Here, the above-mentioned lens-integrated type is used as the mover constituting the electrostatic actuator. An IC such as a DSP for controlling driving of the electrostatic actuator is mounted on the substrate 21.

The camera module is used as a camera unit of a mobile phone, a digital camera, or the like.

[0112]

As described above, according to the present invention,
It is possible to provide an inexpensive electrostatic actuator that is compatible with mass productivity and a method of driving the same. Also, a small camera module using such an electrostatic actuator can be provided.

[Brief description of the drawings]

FIG. 1 is a diagram showing a first embodiment (three systems) of an electrostatic actuator according to the present invention.

FIGS. 2A to 2E are timing charts showing voltage signals applied to electrodes of the electrostatic actuator shown in FIG.

FIGS. 3 (a) to 3 (e) are operation explanatory diagrams for explaining a method of driving an electrostatic actuator according to a modification of the first embodiment shown in FIG. 1;

FIGS. 4A to 4E are timing charts showing voltage signals applied to the electrodes of the electrostatic actuator according to the driving method shown in FIGS. 3A to 3E.

FIG. 5 is a diagram showing a second embodiment of the electrostatic actuator according to the present invention.

FIG. 6 is an explanatory diagram relating to an electrode width of a mover in a second embodiment of the electrostatic actuator according to the present invention.

FIGS. 7A to 7E are timing charts showing voltage signals applied to the electrodes of the electrostatic actuator shown in FIGS. 5 and 6. FIG.

8 is a graph showing a relationship between displacement using a gap as a parameter in the electrostatic actuator shown in FIGS. 5 and 6, and a driving force applied to a mover.

FIG. 9 is a sectional view schematically showing still another modified embodiment of the electrostatic actuator according to the present invention.

FIGS. 10A and 10B are explanatory diagrams of an electrostatic actuator according to the present invention.

FIGS. 11A and 11B are views showing a third embodiment of the electrostatic actuator according to the present invention (the stator is a dielectric film).

FIG. 12 is a timing chart showing voltage signals applied to electrodes of the electrostatic actuator shown in FIG. 11;

FIGS. 13A and 13B are diagrams showing a third embodiment of the electrostatic actuator according to the present invention (movable element is a dielectric film).

FIG. 14 is a diagram showing a fourth embodiment (movable element) of the electrostatic actuator according to the present invention.

FIGS. 15A to 15C are diagrams showing a manufacturing process of a fourth embodiment (movable element) of the electrostatic actuator according to the present invention.

16 (a) and (b) are views showing an electrostatic actuator provided with a stopper (stator side) according to the present invention.

17A and 17B are views showing an electrostatic actuator (a mover side) provided with a stopper according to the present invention.

FIG. 18 is a diagram showing a fifth embodiment of the electrostatic actuator according to the present invention.

FIGS. 19A to 19C are views showing a sixth embodiment (stator, three systems) of the electrostatic actuator according to the present invention.

FIGS. 20 (a) to (d) are views showing a manufacturing process of a sixth embodiment (stator) of the electrostatic actuator according to the present invention.

FIGS. 21A to 21C are views showing a sixth embodiment (a stator, four systems) of the electrostatic actuator according to the present invention.

FIGS. 22 (a) to (c) are views showing a seventh embodiment (stator) of the electrostatic actuator according to the present invention.

FIGS. 23A to 23D are views showing an eighth embodiment (stator) of the electrostatic actuator according to the present invention.

FIGS. 24A to 24D are views showing a ninth embodiment (part of the stator) of the electrostatic actuator according to the present invention.

FIGS. 25A to 25C are views showing a ninth embodiment (part of the stator) of the electrostatic actuator according to the present invention.

26A to 26C are diagrams showing a ninth embodiment (stator) of the electrostatic actuator according to the present invention.

FIGS. 27A to 27D are views showing a tenth embodiment (stator) of the electrostatic actuator according to the present invention.

FIG. 28 is a view showing an application example of the electrostatic actuator according to the present invention.

FIG. 29 is a diagram showing a configuration of a conventional electrostatic actuator.

FIG. 30 is a diagram showing a configuration (dielectric film) of a conventional electrostatic actuator.

[Explanation of symbols]

 1. . . Electrostatic actuator 2a. . . First stator 2b. . . Second stator 3. . . Mover 4 . . 4. Dielectric film . . 5. Dielectric polarization . . Electrode section 7. . . Lens surface

Claims (31)

[Claims] A first stator having at least three systems of first electrodes sequentially arranged in a predetermined direction; and a first stator provided to face the first stator and extended in the predetermined direction. A second stator having one system of second electrodes; and a third electrode disposed between the first stator and the second stator and having an electrode portion facing the first electrode. A movable element comprising: a movable element, wherein a voltage is alternately applied to the first electrode and the second electrode so that the potential of the first electrode or the second electrode is higher than the potential of the third electrode. And an actuator that drives the mover in the predetermined direction by sequentially switching the system of the first electrode in the predetermined direction. 2. A method according to claim 1, wherein the width of the electrode portion provided on the mover in the predetermined direction is 1.5 to 2.0 times the width of each electrode of the first electrode in the predetermined direction. The electrostatic actuator according to claim 1, wherein 3. The electrostatic actuator according to claim 1, further comprising a dielectric film provided so as to cover said first or second electrode. 4. The electrostatic actuator according to claim 1, further comprising a dielectric film provided so as to cover said third electrode. 5. The method according to claim 1, further comprising: means for giving a potential difference when applying a voltage to the second electrode so that the potential of the first electrode is lower than the potential of the third electrode. The electrostatic actuator according to claim 3, wherein 6. The electrostatic actuator according to claim 1, wherein a surface orthogonal to the predetermined direction in which the movable element is driven is an optical element surface. 7. The first and second stators each include a stopper protruding from a surface of the electrode on a surface on which the electrode is provided, and the movable element includes a stopper on a surface on which the third electrode is provided. The electrostatic actuator according to claim 1, further comprising an area for sliding the stopper. 8. The mover includes a stopper on a surface on which the third electrode is provided, the stopper protruding from a surface of the electrode, and the first and second stators include a surface on which the electrode is provided. The electrostatic actuator according to claim 1, further comprising an area for sliding the stopper. 9. A first stator having a first electrode group in which at least three electrodes to which voltages are applied in different orders are sequentially arranged in a predetermined direction, and a first stator facing the first stator. A second stator provided with a planar second electrode extending in the predetermined direction; and a second stator disposed between the first stator and the second stator, A movable element including a first electrode section facing the first electrode group and a second electrode section facing the second electrode; and the first electrode group having a potential higher than the potential of the first electrode section. The potential of any of the electrodes is increased or the second
A sequence of applying a voltage alternately to the first electrode group and the second electrode and applying a voltage to the first electrode group so that the potential of the second electrode is higher than the electrode portion of And a switching circuit for sequentially switching between the two. 10. The static switching device according to claim 9, wherein the switching circuit simultaneously applies a voltage to at least two electrodes adjacent in the predetermined direction when applying a voltage to the first electrode group. Electric actuator. 11. The width of the first electrode portion provided on the mover along the predetermined direction is 1.5 to 2.5 times the width of each electrode of the first electrode group along the predetermined direction. The electrostatic actuator according to claim 9, wherein: 12. The electrostatic actuator according to claim 9, further comprising a dielectric film provided so as to cover said first electrode group. 13. When applying a voltage to the second electrode,
13. The electrostatic actuator according to claim 12, further comprising: means for giving a potential difference so that the potential of the first electrode group is lower than the potential of the first electrode unit. 14. The electrostatic actuator according to claim 9, further comprising a dielectric film provided so as to cover said first electrode portion. 15. When applying a voltage to the second electrode,
15. The electrostatic actuator according to claim 14, further comprising: means for giving a potential difference so that the potential of the first electrode group is lower than the potential of the first electrode unit. 16. The electrostatic actuator according to claim 9, wherein said electrode portion is substantially at a ground potential. 17. The electrostatic actuator according to claim 9, wherein said mover includes an optical element driven together with said mover. 18. The apparatus according to claim 18, wherein said first and second stators are provided with said first and second stators.
A stopper protruding from the surfaces of the electrode group and the second electrode, and the mover includes a region for sliding the stopper on a surface on which the electrode portion is provided. 10. The electrostatic actuator according to item 9. 19. The movable element includes a stopper protruding from the surface of the electrode portion, and the first and second stators include a surface on which the first electrode group and the second electrode are provided. 10. The electrostatic actuator according to claim 9, further comprising an area for sliding the stopper. 20. The electrostatic actuator according to claim 9, wherein the first electrode group includes three electrodes to which voltages are applied in different orders, which are sequentially arranged in the predetermined direction. 21. The electrostatic actuator according to claim 9, wherein the first electrode group is formed by sequentially arranging four electrodes to which voltages are applied in different orders in the predetermined direction. 22. A first stator having a first electrode group in which at least three electrodes to which voltages are applied in different orders are sequentially arranged in a predetermined direction, and a first stator facing the first stator. Provided on the plane extending in the predetermined direction.
A second stator provided with the first and second electrodes, a first electrode portion disposed between the first stator and the second stator, facing the first electrode group, and the second stator. A method of driving an electrostatic actuator having a mover including a second electrode portion facing the first electrode portion, wherein the potential of the first electrode portion is higher than the potential of the first electrode portion. A voltage is applied so that a potential is higher, a voltage is applied so that a potential of the second electrode is higher than a potential of the second electrode portion, and the first electrode is switched by switching electrodes of the first electrode group. Applying a voltage so that the potential of the electrode becomes higher than the potential of the electrode portion of the above; applying a voltage so that the potential of the second electrode becomes higher than the second electrode portion; A method for driving an electrostatic actuator, characterized by repeatedly applying a voltage. 23. The driving of the electrostatic actuator according to claim 22, wherein, when applying a voltage to the first electrode group, a voltage is applied to at least two electrodes adjacent in the predetermined direction at the same time. Method. 24. When applying a voltage to the second electrode,
23. The method according to claim 22, wherein a potential difference is applied so that the potential of the first electrode group is lower than the potential of the first electrode unit. 25. A first fixed device comprising: an image sensor; and a first electrode group provided on the image sensor and having at least three electrodes to which voltages are applied in different orders sequentially arranged in a predetermined direction. A second stator having a planar second electrode provided in opposition to the first stator and extending in the predetermined direction;
A first electrode unit facing the first electrode group, a second electrode unit facing the second electrode, and a second electrode unit disposed between the first and second stators and the second stator. A movable element provided with an optical element that forms an image of light on the first electrode unit, and the potential of any one of the first electrode group is higher than the potential of the first electrode unit, or the second electrode The voltage is applied to the first electrode group and the second electrode alternately so that the potential of the second electrode is higher than the potential of the second electrode, and the order of applying the voltage to the first electrode group is sequentially changed. A camera module comprising: an electrostatic actuator having a switching circuit for switching. 26. The camera according to claim 25, wherein the switching circuit simultaneously applies a voltage to at least two electrodes adjacent in the predetermined direction when applying a voltage to the first electrode group. module. 27. The width of the first electrode portion provided on the mover in the predetermined direction is 1.5 to 2.5 times the width of each electrode of the first electrode group in the predetermined direction. The camera module according to claim 25, wherein: 28. The apparatus according to claim 25, further comprising a dielectric film provided so as to cover said first electrode group.
The camera module as described. 29. When applying a voltage to the second electrode,
29. The camera module according to claim 28, further comprising: means for giving a potential difference so that the potential of the first electrode group is lower than the potential of the first electrode unit. 30. The semiconductor device according to claim 25, further comprising a dielectric film provided so as to cover said first electrode portion.
The camera module as described. 31. When applying a voltage to the second electrode,
31. The camera module according to claim 30, further comprising: means for giving a potential difference so that the potential of the first electrode group is lower than the potential of the first electrode unit.