JPH0880065A - Electrostatic actuator - Google Patents

Abstract

PURPOSE: To obtain an electrostatic actuator capable of being moved in the oblique direction in addition to the uniaxial direction by forming constitution, in which an insulating guide is arranged onto a driving electrode for a first member. CONSTITUTION: An electrostatic actuator has a first member 1 having a plurality of mutually insulated driving electrodes 3 on a transparent insulating supporter 2, a second member 5, in which positive and negative charges are given to an insulating sheet body, the insulating protective films 4 of the driving electrodes 3 and insulating guides 6 arranged at arbitrary angles. Positive, negative and G driving voltage is changed over successively and applied to the stator electrodes 3 of three phase from a driver circuit 10, thus moving the second member by charges electrostatically induced in the high resistor layer of a moving piece and coulomb force working among first electrodes. When the moving piece 5 is shifted and a left end section is brought into contact with the guide 6 because the actuator has the insulating guides 6, however, driving force in the actual direction of movement appears from the vector composition of a driving force and a reaction force. Accordingly, movement in the oblique direction is enabled in addition to the uniaxial direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic actuator, and more particularly to an electrostatic actuator useful for practical use in a display device or the like.

[0002]

2. Description of the Related Art An electrostatic actuator includes a first member having a plurality of drive electrodes insulated from each other and arranged in a predetermined direction and at a predetermined interval on an insulating support and an insulating thin leaf. The second member to which the electric charge is applied is arranged to be in contact with the second member. Then, by switching the voltage applied to the drive electrode, the relative position of the second member with respect to the first member in the predetermined direction is changed by the Coulomb force of static electricity between the first member and the second member. (See JP-A-2-285978, etc.). That is,
A state where no (+) drive voltage, (-) drive voltage, or voltage is applied to the drive electrode of the first member (G: ground state)
And the voltage is applied by sequentially switching the second member, and the second member moves due to the Coulomb force acting between the charge electrostatically induced in the high resistance layer of the second member and the electrode of the first member. It is a thing.

[0003]

In the electrostatic actuator, the basic principle has been established, and practical studies are being actively conducted, and each element must be examined in more detail. In particular, when it is put to practical use as a display device such as an advertisement display, it is required to move in more than one axis direction. it can. However, such an electrostatic actuator is difficult to manufacture and has a complicated moving circuit, which causes a problem of high cost. From the viewpoint of cost, there is a demand for an electrostatic actuator that can be moved in one direction, for example, in an oblique direction even if it cannot be moved in the directions of multiple degrees of freedom, and that can be manufactured at low cost. .

Further, for example, when the electrostatic actuator is used while standing vertically, it is required to hold the second member (moving element) even when the movement is stopped or the voltage is not applied. There are the following methods for holding the mover. (1) By the relative movement of the first member and the second member,
The first and second members are held by using a frictional force due to slight charging or the like. However, in this case, when the electrostatic actuator is erected vertically, if the thickness of the second member is 50 μm or less, it is lightweight and can be held for a long time, but the thickness of the second member is 50 μm. When the weight becomes heavy as described above, the gravity becomes larger than the frictional force, and there is a problem that it cannot be held.

(2) When an analog signal such as a sine wave is used as the drive circuit, a low frequency of about 0.1 to 1 Hz is applied as a three-phase sine wave to the three-phase drive electrodes, and the second The member (moving element) can be held without moving. (3) Further, as the driving circuit, (+), (-), (G)
When using the pulse driving for switching
Approximate three-phase sine wave as shown in (3) can be held by three steps of reciprocating movement.

However, the methods (2) and (3) described above have a problem that the voltage cannot be maintained when the power supply is shut off due to a power failure or the like because the voltage must be constantly applied.

[0007]

According to a first aspect of the present invention, in order to achieve the above object, a plurality of drive electrodes insulated from each other are arranged on an insulating support in a predetermined direction and at predetermined intervals. Is disposed so as to be in contact with the second member to which positive and negative charges are applied to the insulating thin leaf body, and the first member and the first member generated by switching the applied voltage to the drive electrode are disposed. In an electrostatic actuator including drive means for changing the relative position of the second member in a predetermined direction with respect to the first member by the Coulomb force of static electricity between the second member and the second member, switching of the voltage applied to the drive electrode. Insulating guides are arranged on the drive electrodes of the first member as means for changing the relative position of the second member with respect to the first member in a predetermined direction different from that of the first member. Features It is to provide an electrostatic actuator.

According to a second aspect of the present invention, in the electrostatic actuator according to the first aspect, at least one of the first member and the second member holds the other member when the electrostatic actuator is not driven. First when not driven with
Another object of the present invention is to provide an electrostatic actuator having holding means on the fixed side of one of the member and the second side of the second member.

According to a third aspect, in the electrostatic actuator according to the second aspect, as a means for holding the other member, the other member is brought into contact with the other member when no voltage is applied, and the other member is contacted when no voltage is applied. Another object of the present invention is to provide an electrostatic actuator provided with a piezoelectric element so as not to come into contact with.

[0010]

According to the structure of claim 1, an insulating guide is separately arranged on the insulated drive electrode of the first member as a means for moving the first member in a direction different from the movement of the drive electrode in the predetermined direction. Since the second member moves and contacts the insulating guide, the second member moves in the direction of the combined force of the driving force and the repulsive force (angle between the driving electrode and the guide).

According to the second aspect of the present invention, the first non-driving
It is possible to hold the other drive side on the fixed surface of one of the member or the second member. According to the structure of claim 3, the piezoelectric element is held in contact with the moving side by the displacement thereof while the voltage is not applied, so that the other driving side can be held.

[0012]

Embodiments of the present invention will be described below with reference to the accompanying drawings. The electrostatic actuator of the present invention is not limited to a transparent one, but a transparent electrostatic actuator is useful when applied to a display device or the like. Therefore,
In the following description, a transparent electrostatic actuator will be mainly described.

FIG. 1 is a schematic configuration diagram of an electrostatic actuator showing a first embodiment of the present invention. FIG. 2 is a vector diagram showing the moving direction of the mover after contacting the insulating guide in the first embodiment of the present invention. The electrostatic actuator of the present invention has a first plurality of transparent drive electrodes (3) insulated from each other on a transparent insulating support (2).
Member (1), a second member (5) to which positive and negative charges are applied to the insulating thin leaf, an insulating protective film (4) for insulating the drive electrodes of the first member from each other, an insulating protective film ( 4) has an insulating guide (6) arranged at an arbitrary angle.

As shown in FIGS. 1 and 2, the first member (1) has a transparent drive electrode (3) embedded on a transparent insulating support (2). The transparent electrostatic actuator having the transparent first member is known per se, and for example, the electrostatic actuator described in JP-A-4-340372 can be used. Insulating support (2)
As, for example, a transparent glass plate or polycarbonate,
Plastic films such as polyethylene terephthalate, polybutylene terephthalate, polyether sulfone, polyarylate, and polyimide can be used.

As a method of imparting positive and negative charges to the second member (5), for example, an antistatic agent having a weak antistatic effect is applied to the surface of the insulating thin leaf body (6) so that the surface specific resistance is reduced. A method of providing the resistor layer (7) in the range of 10 ¹¹ to 10 ¹⁵ Ω / □, or a method of forming a double-sided electrode by using the same member as the first member as the second member can also be adopted.

For example, each strip electrode (3) formed on the insulative support (2) is a conductive material formed on the surface of the insulative support (2) by a lithography technique using a photoresist material. It is formed by a method of patterning a thin film of a material (for example, indium oxide-tin oxide or the like). Usually, a protective layer (4) made of a transparent insulating film, a transparent insulating paste, and a transparent insulating ceramics or a vapor deposition film is provided on each surface of the strip electrode. Also,
Usually, since the strip-shaped electrode of the insulating support (2) has a three-phase structure, a through-hole technique on the back surface is required to take out the assembly line (7). However, when an insulating material having a high withstand voltage such as ceramics is used, it is possible to form a two-layer assembly line through the insulating material, so that the first member can be formed without using the through hole technique. It is possible.

The electrostatic actuator used in the present invention comprises a first member (stator) having drive electrodes which are insulated from each other on an insulating support and arranged at predetermined intervals, and an insulating thin film such as an insulating film. The second member (moving element) is provided with a resistor layer so that positive and negative charges are applied to the body, and the stator and the moving element are arranged in contact with each other. Then, due to the action of static electricity, the mover is momentarily levitated and moved while reducing friction (Japanese Patent Laid-Open No. 2-28597).
No. 8, etc.).

That is, from the drive circuit (10) composed of the switching element (11), the high voltage power supply (12) and the switching circuit (13) to the three-phase stator electrode (3).
The driving voltage of (+), (-), and (G) is sequentially switched to and applied to the electrodes, thereby acting between the charge electrostatically induced in the high resistance layer of the mover and the electrode of the first member. The second member (moving element) is moved by the Coulomb force.

Insulating guide (6) which is a feature of the present invention
With reference to FIG. 2, an operation of moving in an oblique direction in addition to the uniaxial direction will be described with reference to FIG. As the insulating guide (6), the same material as that of the insulating support (2) can be used. Good.

In FIG. 1, the guides are (6), (6 ') and 2
Although it is provided at several places, it may be provided at a plurality of places depending on the moving direction. As shown in FIG. 2, when the direction of the plurality of strip electrodes is the X direction, the mover (5) is first moved in the Y1 direction, and when the left end of the mover (5) contacts the guide (6), The driving force (f3) in the actual moving direction appears from the vector combination of the driving force (f1) and the repulsive force (f2). The direction of f3 is determined by the direction in which the guide (6) is arranged, and the mover (5) moves in an oblique direction having an angle of θ with respect to the Y direction.

After that, when it is moved in the Y2 direction and the right end portion of the moving element (5) again contacts the guide (6 '), it moves in the downward oblique direction in FIG. By repeating this operation, in addition to the uniaxial direction (Y direction in FIG. 2), continuous movement in the oblique direction (θ direction in FIG. 2) becomes possible, and the display effect of the display device can be improved. FIG. 3 is a sectional view of a holding mechanism used in the third embodiment of the present invention (a guide is not shown). As a specific holding mechanism, for example, a piezoelectric element, a piezoelectric film, an electrostrictive element, a spring, an electromagnetic solenoid, or the like can be used, but FIG. 3 shows the case where the piezoelectric element is used. The holding mechanism (20) is fixed to the chassis (30) of the electrostatic actuator so that it can be held without applying a voltage. When the driving voltage of the electrostatic actuator is applied, the holding mechanism (20) is deformed as shown by the dotted line in FIG. 3, and a gap is created between the holding mechanism (20) and the moving element (5). You can move without.

FIG. 4 is a detailed view of the holding mechanism (20). In the holding mechanism (20), a ceramic piezoelectric element (21) is attached to a shim (22), and the shim (22) is attached.
The end of is fixed to the support plate (23). Support plate (2
3) may be replaced by the chassis (30) described above.
A well-known Pb (Zr,
Ti) O ₃ PZT system, PbTiO ₃ PT system, (Pb,
A PLZT system of La) (Zr, Ti) O ₃ can be used. The shim (22) is an elastic plate made of phosphor bronze or the like. The shim (22) is
It is preliminarily processed into a shape that holds the mover (5). When voltage is applied, the chassis (3
The distance (G) between 0) and the mover (5) is usually 0.05.
.About.0.5 mm is desirable, and may be appropriately selected depending on the physical property value of the piezoelectric element, the shape of the shim, the applied voltage, and the like.

In FIG. 4, the piezoelectric element is shown as a bimorph type, but it may be a unimorph type in which piezoelectric elements are attached to both sides of the shim, or a shim portion to which no piezoelectric element is attached is curved and applied. If the high voltage of the drive circuit of the electrostatic actuator is used as the voltage, it is not necessary to lengthen the shape of the shim. Piezoelectric elements, like electrostatic actuators,
Since the current consumption is small, the high voltage of the drive circuit of the electrostatic actuator can be used, which is preferable.

[0024]

According to the present invention, the following effects can be obtained. (1) In addition to the uniaxial direction, it is possible to provide an electrostatic actuator that can be easily moved in an oblique direction at a low price.
It is useful as a display device. (2) The movable element and the stator can be held even when no voltage is applied, which is practically useful for the electrostatic actuator.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an electrostatic actuator showing a first embodiment of the present invention.

FIG. 2 is an explanatory diagram of a moving direction of the electrostatic actuator that is the first embodiment of the present invention.

FIG. 3 is a schematic configuration diagram of an electrostatic actuator showing a second embodiment of the present invention.

FIG. 4 is an operation explanatory view of a holding mechanism of an electrostatic actuator that is a third embodiment of the present invention.

FIG. 5 is an explanatory diagram of a conventional applied voltage for holding the first member and the second member.

FIG. 6 is an explanatory diagram of a conventional applied voltage for holding the first and second members.

[Explanation of symbols]

 (1): First member (5): Second member (6): Insulating guide (10): Drive circuit (20): Holding mechanism

Claims (3)

[Claims] 1. A first member having a plurality of drive electrodes insulated from each other and arranged in a predetermined direction and at a predetermined interval on an insulating support, and positive and negative charges are applied to the insulating thin leaf body. The first member is arranged so as to be in contact with the second member to be applied and is generated by switching the voltage applied to the drive electrode.
In the electrostatic actuator including a driving means for changing the relative position of the second member with respect to the first member in the predetermined direction by the Coulomb force of static electricity between the member and the second member, An insulating guide is arranged on the drive electrode of the first member as means for changing the relative position of the second member relative to the first member in the predetermined direction by changing the applied voltage. An electrostatic actuator characterized by being provided. 2. The electrostatic actuator according to claim 1, wherein at least one of the first member and the second member has means for holding the other member when the electrostatic actuator is not driven. 3. A piezoelectric element is provided as a means for holding the other member so as to come into contact with the other member when no voltage is applied and not come into contact with the other member when no voltage is applied. 2. The electrostatic actuator according to 2.