JPS6395866A - Electrostatic actuator - Google Patents

Abstract

PURPOSE:To miniaturize a device at a low cost, by applying an alternating electric field between electrodes on every phase of a first specific-plate-formed unit and electrodes on a second plate-formed unit. CONSTITUTION:So far as an electrostatic actuator is concerned, on the surface of the rotor 1 of a dielectric unit, electrodes 1a are arranged radially at specified intervals. On the rotor 1, a rotation shaft 2 is pivotally fitted and is supported pivotally and rotatably on the bearing 7 of upper and lower plates 5, 6. On the upper surface of the lower plate 6 confronted with the rotor 1, substrates 4 are laminated, and the confronted surface, electrode patterns 3 are arranged. The electrodes are formed at specified intervals radially to the axis of the rotation shaft 2 of the rotor 1. A distance between the rotor 1, the substrates 4, and the upper plate 5 s retained to be a specified distance by spacers and screws 9a-9d and the bearing 7, and the rotor 1 and the substrates 4 are composed to be rotatably moved in the directions of arrow heads A, B shown in figure. Then, by diminishing a gap between the substrates 4 and the rotor 1, a device can be miniaturized and formed to be of a thin type.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electrostatic actuator that uses electrostatic force to move a mover eight times.

[Prior Art] Conventional actuators mainly utilize electromagnetic force, and due to their characteristics, they must be equipped with electromagnetic coils, permanent magnets, etc., resulting in complex structures and extremely large power consumption. Ta. Therefore, the amount of heat generated by the actuator was also large.

Therefore, in order to solve these problems, a synchronous motor using an electret (for example, Utility Model Application No. 57-98191, etc.) has been proposed as a motor that uses electrostatic force instead of electromagnetic force. It is known that the driving force of an actuator using such electrostatic force is proportional to the square of the applied voltage (V) and inversely proportional to the pressure between the stator and the movable element 11iff(d).

[Problems to be solved by the invention] However, the electret type actuator requires the use of a special electret, and the production of the rotor itself requires complicated processes such as attaching electret pieces, making it difficult to miniaturize. It's not easy.

Furthermore, production of electrets requires a special process, which inevitably increases costs.

[Means for Solving the Problems] The present invention has been made to solve the above-mentioned problems, and in order to provide an inexpensive actuator that is small in size and has a simple configuration, an embodiment of the present invention is as follows. It has the following configuration.

That is, comb-shaped electrodes having a predetermined number N of electrode patterns at predetermined intervals on the circumference are arranged on concentric circles with different M phases,
and a first plate-shaped body configured such that the electrode patterns for each phase on each circumference are not lined up on a radial line centered on the center of the concentric circle, and a surface of the first plate-shaped body opposite to the electrode surface. The device includes a first plate-like body in which electrodes are arranged at predetermined intervals, and a second plate-like body that is rotatable about the center of the concentric circle while maintaining a predetermined interval.

[Function] In the above configuration, the electrodes for each phase of the first plate-shaped body,
By applying an alternating current between the electrodes of the second plate-like body, the first plate-like body and the second plate-like body are relatively rotated.

[Example] Hereinafter, an example according to the present invention will be described in detail with reference to the drawings.

[First Embodiment] FIG. 1 is an exploded perspective view of an embodiment according to the present invention, and FIG. 2 is a sectional view thereof.

1 in the figure is a rotor consisting of a layered body with insulation properties,
Electrodes 1a are arranged radially on the surface of the rotor 1 at predetermined intervals. In this embodiment, the rotor 1 is made of glass. This rotor 1 may be made of phenol resin or the like. Reference numeral 2 denotes a rotating shaft to which the rotor 1 is attached, and is rotatably supported by a bearing 7 provided on the upper plate 5 and a bearing 8 provided on the lower plate 6. Note that the rotor 1 has a thickness of 0.4 mm.

The diameter is 66 mm, and the rotating shaft 2 has a diameter of 1.5 mm.

A substrate 4 is laminated on the upper surface of the lower plate 6 facing the rotor 1, and an electrode pattern 3 is provided on the surface of the substrate 4 facing the rotor. The electrodes are formed by vapor deposition at predetermined intervals radially with respect to the axis of the rotating shaft 2 of the rotor 1. Various methods such as etching can be used for patterning the electrode. Although Cr is used for the electrode 3, it may be patterned using various conductive metals such as Ag, Au, Au, Cu, etc. Ti or Ta (tantalum) may be used to prevent the electrode from melting due to discharge. You may use high melting point metals such as.

In this embodiment, the upper plate 5, lower plate 6, and substrate 4 are made of glass. However, these materials are not limited to glass, and may be made of plastics, ceramics, or the like as long as they have insulation properties.

The rotor 1, the substrate 4, and the upper plate 5 are held at a predetermined gap by spacers, screws 9a, 9b, 9c, and 9d, and bearings 7 and 8, and are configured to be rotatable in the direction of arrow A or arrow B in the figure. ing.

In this example, the average pattern width of the electrode 3 is 1 mm,
Formed with a pattern pitch of 2 mm, 'R pole 3 and rotor 1,
The distance between the rotor 1 and the upper plate 5 is both 0.25 mm. Then, as shown in the figure, φA11. There is a three-phase drive output of φB12° and φC13, and the output of each phase is sequentially connected to the electrode 2 as shown in the figure, and a predetermined voltage is applied here to generate a rotating electric field on the substrate 4 and rotate the rotor 1. I'm letting you do it.

The timing of voltage application to the electrode 3 by this drive circuit 10 is shown in FIGS. 3(A) to 3(C).

Here, to simplify the explanation, the electrode pattern of the substrate 4 is 9.
The case will be explained below. Note that the hatched lines 20, 21, and 22 in the figure are part of the electrodes of the rotor 1, and the electrodes on the substrate 4 are connected to the three-phase output signal lines from the drive circuit 10 (φA11. φB12.φC13), as shown in the figure, the electrodes 20 to 22 of the rotor 1 and the electrodes on the substrate 4 are configured with a pattern pitch shifted from each other.

In this embodiment, the rotor 1 is driven to rotate, for example, in the direction of the arrow A shown in the figure, using the attractive force acting between the electrodes on the substrate 4 and the electrodes on the rotor 1. Specifically, all the electrodes of the rotor 1 are grounded, and voltages are sequentially applied to the electrodes on the substrate 4.

That is, first, when the electrodes are in the positional relationship shown in FIG. 3(A), a driving voltage is applied to φA. Then, the electrode φA in the figure
An attractive force acts between the rotor electrode 20 and the rotor electrode 20, causing the rotor 1 to rotate in the direction of arrow A in FIG. 3(A). When the rotor 1 rotates and comes to the position shown in FIG. 3(B), the board 4
The voltage application to the electrode φA is stopped, and the voltage is applied to the electrode φB. Therefore, an attractive force acts between the electrode φB and the rotor electrode 21, causing the rotor 1 to further rotate in the six directions of the arrows.

Similarly, the rotor 1 is in the position shown in FIG. 3(C).

When the rotation is reached, the voltage application to the electrode φB is stopped, and the voltage application to the electrode φC is started. This causes an attractive force to work between the electrode φC and the rotor electrode 22, causing the rotor 1 to rotate in the direction of arrow A. Then, the rotor 1 can be continued to rotate by returning to the position shown in FIG. 3(A) and repeating the above-described control.

Motors that use electrostatic force have an advantage in terms of torque than motors that use electromagnetic force in the case of small scales on the order of 10 μm or less, and when manufacturing motors, microfabrication technology is used to change the unit of force generation. It is effective to reduce the size and increase the degree of integration. This integration technology is an important point. Therefore, what was actually manufactured was a shape similar to that shown in Fig. 1, a total of 60 substrate electrodes 3, and 1 rotor.
The total number of electrodes is 72, and the gap between the electrodes is 10 μm.

By miniaturizing this pattern pitch and gap,
The torque generated in the rotor 1 becomes larger.

[Second Example] In the configuration shown in FIG. 1, when there are 60 substrate electrodes, 60 drive signal lines are also required. This poses a major obstacle to further downsizing the configuration. Another embodiment of the present invention that improves this point will be described with reference to the drawings from FIG. 4 onwards.

FIG. 4 is a schematic diagram showing the outline of the planting in this example.
Components similar to those in the figure are given the same numbers.

Electrode patterns 1a are arranged on the rotor 1 at a predetermined pitch radially from the rotating shaft 2, and are held at a ground potential by a connecting means (not shown). In this embodiment, the electrode pattern on the substrate 4 is different from that in FIG. 1, and comb-shaped electrode patterns for each phase are arranged on concentric circles as shown. Here, 4
1 to 43 are electrode base lines for each phase, and 45 to 47 are electrode branch lines arranged at predetermined intervals for each phase. Each electrode branch line 45-47
are arranged concentrically at predetermined intervals without being lined up on a radial line centered on the rotating shaft 2. The electrode pattern 1a of the rotor 1 is configured to face any one of the electrode branch lines 45 to 47 on the substrate 4 no matter where the rotor 1 is located.

Next, the operation of this embodiment will be explained in FIGS. 5(A) to (C) and 6.
This will be explained with reference to FIGS. (a) and (b).

5A to 5C show a part of the rotor 1 cut away for explanation, and the electrode pattern of the substrate 4 is also simplified as in FIG. 3. Here, the same components as in FIG. 4 are given the same numbers. Unlike FIG. 4, lead electrodes 51 to 53 for connecting the electrodes of each phase of the substrate 4 and the drive circuit 10 are formed by extending electrode branch lines in the outer circumferential direction. The electrode base line is cut at the extension point. By forming in this way, the attraction force generated at the electrode extraction portion and the attraction force generated between the other electrodes are at the same timing, and smooth and efficient rotation can be obtained. Note that the method for taking out the electrodes is not limited to this example, and a through hole may be formed in each electrode base line portion and the back surface of the substrate, and the lead electrode portion may be formed from the back surface.

FIG. 6(a) shows the timing of voltage application from the drive circuit 10 to each electrode on the substrate 4 in this embodiment.

Shown in (b).

Here, Fig. 6(a) shows (0/+V) V for each phase (each electrode).
When a pulse voltage of (+V) is applied, FIG. 6(b)
The case is shown in which an AC voltage of /-V)V is applied.

φA11. φB12. When a pulsed voltage as shown in FIG. 6(a) (the horizontal axis represents time t) is applied to each phase of φC13, a moving electric field is generated in the direction of arrow B in FIG. Then, an attractive force is generated between the rotor 1 and the electrodes,
A driving force follows in the same direction of arrow B with a certain slippage. This is the same even when the alternating current voltage shown in FIG. 3(b) is applied.

However, the phase order is preferably C1λ, B2, A, 100, C... (- means a phase shift of 180°). To move the rotor 1 in the opposite direction, it is sufficient to reverse the phase order of the applied voltages, and in the case of the embodiment, it is sufficient to replace two of the three phases.

Furthermore, the number of phases may be any one that can generate the fJiO electric field.

The operating principle when the potential shown in FIG. 6(a) or (b) is applied to each electrode of the substrate 1 will be explained with reference to FIGS. 5(A) to 5(C).

The electrodes 8i1a of the rotor 1 and each electrode of the substrate 4 are shown in FIG.
When in the positional relationship A), Fig. 6 (a) or (b)
As shown by P, a potential of +V is applied to the substrate electrode φC. Then, an attractive force acts between the electrode branch wire 47 (φC) and the electrode 1a, and a rotational torque is generated in the rotor 1 in the direction of arrow B, so that the rotor 1 starts rotating. When the position shown in FIG. 5(B) is reached, as shown in Q in FIG. 6 (10 V is applied to the φB electrode, and the voltage application to the φC electrode is stopped.

As a result, the electrode branch wire 46 (φB) and the rotor wire 4f
A suction force acts between 11a and continues to rotate the rotor 1 in the direction of arrow B. Similarly, when the positional relationship is shown in FIG. 5(C), +■ main voltage is applied to the substrate electrode only to the electrode branch line φA as shown by R in FIG.
) and the rotor electrode 1a, and the rotor 1 is further rotated in the direction of arrow B. The position shown in FIG. 5(A) is then reached again, and the applied voltage is also at the same timing as the applied voltage at time P, as shown by S in FIG.

By miniaturizing this pattern pitch and gap,
The torque generated on the rotor 1 becomes larger.

Therefore, in reality, this electrode pattern is further subdivided, and the electrode pattern in this case is shown in Figures 7 (A) and (B).
).

Here, FIG. 7(A) shows a part of the electrode pattern of the substrate 4, and the number of electrode branch lines for each phase is 24. FIG. 7(B) shows a part of the electrode pattern of the rotor 1, which consists of a total of 24 radial patterns. Since this pattern is formed by vapor deposition or the like, it can be further subdivided, and the pattern pitch can be set to several micrometers or less.

By making the pattern pitch finer in this manner, an electrostatic actuator with even greater rotational torque can be provided.

In addition, although all the above explanations were made with the electrode pattern only on one opposing surface of the rotor, it is of course possible to have the electrode pattern on both sides. By using both sides, the driving force can be doubled.

As explained above, by forming the electrodes of the substrate 4 and the rotor 1 by patterning, the following effects can be obtained.

(1) By creating electrodes by patterning and miniaturizing the gap between the substrate and rotor, it becomes possible to create a small and thin actuator.

(2) With the miniaturization of the gap, the applied voltage can be reduced,
Actuators with lower power consumption are possible.

(3) A special material such as electret is not required for the rotor, and an inexpensive layered material such as glass or phenol resin may be used.

(4) Since it is driven by electrostatic force, power consumption is extremely low and there is no risk of heat generation due to Joule heat.

(5) Since the number of connection lines from the electrodes is minimized, wiring is extremely easy and simple, and pattern miniaturization is also extremely easy.

[Effects of the Invention] As described above, according to the present invention, it is possible to provide an electrostatic actuator that uses inexpensive dielectric materials instead of special materials, has low power consumption, and is suitable for miniaturization with easy electrode wiring. .

[Brief explanation of the drawing]

Figure 1 is an exploded perspective view of one embodiment of the present invention, Figure 2 is a sectional view of the embodiment shown in Figure 1, and Figures 3 (A) to (C).
is a diagram for explaining the operating principle of this embodiment, FIG. 4 is a diagram showing an electrode pattern of another embodiment according to the present invention, and FIGS. 5(A) to (C) are diagrams for explaining the operation of another embodiment. Figures 6(a) and 6(b), which are diagrams for explaining the principle, show the electrode drive of this embodiment. In the figure, 1... rotor, 2... rotating shaft, 3. la. 20-22...electrode, 4...substrate, 5...upper plate,
6... Lower plate, 7.8... Bearing, 9a-9d... Spacer and screw, 10... Drive circuit, 41-43...
- Electrode base line, 45-47... Electrode branch line. Patent applicant Canon Corporation Figure 1 Figure 2 Figure 4 Figure 6 (a) Figure 6 (b)

Claims (2)

[Claims] (1) Comb-shaped electrodes having a predetermined number N of electrode patterns at predetermined intervals on the circumference are arranged on concentric circles with different M phases,
and a first plate-shaped body configured such that the electrode patterns for each phase on each circumference are not lined up on a radial line centered on the center of the concentric circle, and the first plate-shaped body has a rotation axis. a second plate-like body having electrodes arranged at predetermined intervals on a surface facing the electrode surface of the body; and the second plate-like body is rotatable while maintaining a predetermined interval from the first plate-like body. and support means for supporting the second plate-like body rotation axis so as to be at the center of a concentric circle of the first plate-like body. (2) The external connection portion of the first plate-like body is configured by extending the electrode pattern of at least one comb-shaped electrode for each phase. Electrostatic actuator.