JPH052974A - Electrostatic relay - Google Patents

Abstract

PURPOSE:To accomplish an electrostatic relay with higher possibility of practical application, which presents a good large electrostatic power when a driving voltage is impressed and with which it is easy to take a variety of modes. CONSTITUTION:An electrostatic relay concerned is equipped with a stationary side base 2a. which has a stationary contact 21 and a stationary side driving electrode 11, and a movable plate 13 having a movable contact 22 and a movable side driving electrode, wherein cantilever supporting is made so that displacement in the direction of approaching and separating is possible in the condition that the movable plate 13 confronts the stationary side base 2a. The stationary contact 21 is positioned facing the movable contact 22, and the stationary side driving electrode 11 positioned facing the movable side driving electrode, and electrets 8, 9 having different polarities are installed ahead of both sides of the movable plate 13, which is thus displaced with impression of a voltage on the driving electrodes.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic relay that uses electrostatic force (Coulomb force) to contact and separate contacts.

[0002]

2. Description of the Related Art FIGS. 8 and 9 each show a conventional electrostatic relay. These conventional electrostatic relays have a problem that the electrostatic force when a drive voltage is applied is not sufficient.
The electrostatic relay 150 shown in FIG. 8 includes fixed-side bases 151 and 151 that also serve as fixed-side drive electrodes and a movable plate 152 that is also a movable-side drive electrode. When the movable plate 152 faces the fixed-side base 151, the contacts are It is supported at one end (cantilevered support) so that it can be displaced toward and away from it. Then, the fixed side substrate 1
A fixed contact 153 is provided on the surface of the movable plate 15
2 has a movable contact 154 at a position facing the fixed contact 153.
Is provided, and the movable contact 15 is moved by an electrostatic force generated by applying a driving voltage between the fixed-side base body 151 and the movable plate 152.
4 and the fixed contact 153 come into contact with and separate from each other.

In this electrostatic relay 150, an electret is used for the movable plate 152 in order to secure an electrostatic force, but an electrostatic force necessary and sufficient to cause an appropriate displacement in the cantilever support type movable plate 152. It is difficult to obtain, and its practicality is not good enough. The electrostatic relay 160 of FIG.
Comprises a fixed-side insulating base 161 having a fixed contact 171 and a fixed-side drive electrode 172, and a movable plate 162 having a movable contact 173 and a movable-side drive electrode function. The movable contact 173 faces the fixed contact 171 while being supported by the frame portion 163 so that the seesaw can move in a face-to-face state, and the fixed-side drive electrodes 172 are provided on both sides of the fulcrum 165 of the seesaw movement.
The movable plate 162, which is the movable side drive electrode, faces each other, and the seesaw motion of the movable plate 162 is generated by the voltage application to both drive electrodes, so that the contacts 171 and 173 are brought into contact with and separated from each other.

However, it is difficult to secure a necessary and sufficient electrostatic force for causing an appropriate displacement. If the drive voltage is increased, the electrostatic force will be strengthened, but since the distance between the contacts cannot be made too large, there is a limit to increase the drive voltage and it becomes difficult to use, and the practicality is lost. Even if the distance between the contacts is shortened, the electrostatic force is strengthened, but the withstand voltage between the contacts is reduced, so that the practicality is lost.

In the case of relays, so-called single mode (details will be described later) and double mode (details will be described later).
If you take such forms, the usability will increase. However, the electrostatic relay of FIG. 8 is difficult to take the single mode, and the electrostatic relay of FIG. 9 is difficult to take the single mode and the double mode.

[0006]

SUMMARY OF THE INVENTION In view of the above circumstances, it is an object of the present invention to provide a highly practical electrostatic relay which has a sufficiently strong electrostatic force when a driving voltage is applied and can easily take various modes. .

[0007]

In order to solve the above-mentioned problems, an electrostatic relay according to the present invention has a fixed base body having a fixed contact and a fixed side drive electrode, a movable contact and a movable side. A movable plate having a drive electrode is provided, and the movable plate is supported at one end so that it can be displaced in the approaching and separating direction while facing the fixed-side base body, and the fixed contact faces the movable contact and drives the fixed side. Electrodes face the movable-side drive electrode, and electrets of different polarities are arranged opposite to each other on the front side of the movable plate, and displacement of the movable plate occurs due to voltage application to the drive electrode. It takes the structure.

The present invention will be specifically described below. Usually, the fixed side drive electrodes are arranged on both sides of the movable plate, respectively, and in this case, each electret is provided on each fixed side drive electrode. On the movable side, if the movable plate is made of a conductive material, the movable plate can also serve as the movable side drive electrode as in claim 3, but in this case, an insulating film is formed on the surface of the movable plate. To form a movable contact on the insulating film. Of course, the movable side drive electrode may be separately formed on the insulating film similarly to the movable contact. In this case, the movable plate may be made of an insulating material.

On the fixed side, as in claim 4, an insulating film is provided on the surface of the fixed side substrate, and the fixed side drive electrode and the fixed contact are formed on the insulating film, or the fixed side substrate is formed. If is made of a conductive material, a fixed side drive electrode is formed on the fixed side base itself using part or all of the base, and an insulating film is provided on the surface of the fixed side base. You may make it form a fixed contact.

In the case of an electrostatic relay, electric charges are accumulated between the driving electrodes by applying a driving voltage, but in order to quickly shift the movable plate to another state, the electric charges are immediately discharged when the applied voltage is removed. It is necessary, and in this case a discharge circuit is required. In addition, while the signal voltage for control is several V to several tens of V in a normal electronic circuit, the drive voltage of the electrostatic relay is about several tens of V, so a signal voltage of several V to several tens V is applied. If it is going to be used, a booster circuit for boosting the voltage to about several tens of V is required in the front stage of the relay.

Therefore, it is very useful, for example, to provide a driving circuit portion on the fixed side base as in claim 5. The driving circuit section does not have to include both the discharging circuit and the boosting circuit, and may include all or part of either one of the circuits. The driving circuit unit may be provided not only on the fixed side but also on the movable side, or on both the movable side and the fixed side.

Further, in the case of the electrostatic relay, there are various modes. For example, there are fixed contacts on both sides of the movable plate,
In the state where the drive voltage is not applied, neither contact on both sides is in contact with the movable contact but only one of the fixed contacts is applied when the drive voltage is applied. In the stable state, the movable plate is attracted to one of the electrets, and the movable plate is attracted to the other electret only while the drive voltage is applied (monostable single mode), or even in the steady state. In the latched state where the movable contact and the fixed contact on one side are in contact with each other, and the state is switched to the latched state where the movable contact and the fixed contact on the other side are contacted by the voltage application to the drive electrode (bistable double mode), etc. There is.

Examples of electrets of different polarities used in the present invention include ones that are permanently polarized in opposite directions, ones that have substantially permanent charges of opposite polarities, and the like. . A semiconductor substrate such as a silicon single crystal substrate can be used for the fixed-side substrate and the movable plate substrate.

On the movable side, masks having a predetermined pattern are provided on both front and back surfaces of the silicon single crystal substrate, and anisotropic etching is performed to form a movable side substrate having a movable plate also serving as a movable side electrode. it can. On the fixed side, an insulating film is formed on the surface of the silicon single crystal substrate, and fixed contacts and fixed side drive electrodes (further electrets) are provided on it. Semiconductor elements such as transistors, diodes, etc., and impedance elements such as resistors, capacitors, etc. that compose the above can be easily created, and a high-concentration doping layer (usually an impurity high-concentration region of the opposite conductivity type to the substrate) is formed and It can also be used as a fixed side drive electrode.

Further, a silicon single crystal wafer (semiconductor wafer) having an area for a plurality of movable bases and fixed bases is used to simultaneously process a plurality of wafers and divide them into a plurality of movable wafers. It is also possible to obtain the substrate and the fixed-side substrate at the same time. Furthermore, it is very effective to bond the silicon single crystal wafers having a plurality of fixed-side substrates formed thereon to the upper and lower sides of the silicon single crystal wafer having the plurality of movable-side substrates formed, and then separate the wafers individually. It can be manufactured efficiently.

The above-described silicon single crystal wafer can be processed by applying the microfabrication technology and photolithography technology used in ordinary semiconductor device manufacturing. Therefore, very small ones can be mass-produced easily and inexpensively. Things can be mass-produced.

[0017]

In the electrostatic relay according to the present invention, since the electrets are arranged on both sides of the movable side driving electrode, a necessary and sufficient electrostatic force can be secured when the driving voltage is applied. This is because electrets having different polarities cooperatively generate an electrostatic force that moves the movable plate. That is, one of the electrets having different polarities exerts a repulsive force and the other one exerts a suction force, so that the movable plate is displaced in the same direction.

Since some electrets are small and sufficiently strong, a strong electrostatic force can be obtained by simply using different polarities without increasing the driving voltage or reducing the gap between the contacts. Since it is generated, it is realistic and highly practical. Further, in the electrostatic relay of the present invention, the movable plate is supported at one end (cantilever support).
This structure is advantageous in that the structure is simple and the size can be easily reduced, as compared with the structure in which the movable plate performs the seesaw motion with the central support as in the conventional example of FIG.

Next, the point that various modes can be easily taken will be described. In FIG. 6, one of the electrets (+ electret) having different polarities on the fixed side drive electrodes arranged on both sides of the movable side drive electrode has a positive surface facing the movable side drive electrode, and the other surface (− electret). Assuming that the surface facing the movable side drive electrode is negatively and permanently polarized and the apparent charge amount of both is the same, the distance (travel) between both drive electrodes and the electrostatic force (in the movable side drive electrode This represents the relationship between the torque) and the spring load. However, although the electrostatic force and the torque due to the spring load act in opposite directions, they are illustrated in the same direction for convenience in FIG.

If the potentials of both drive electrodes are equal, when both drive electrodes are parallel to each other, the electrostatic force by both electrets is 0, and the movable plate does not move and maintains the neutral position. If the movable drive electrode is tilted to the + electret side (upper side), the electrostatic force of the + electret overcomes the electrostatic force of the − electret, and a torque that tends to lean toward the + electret side acts on the movable electrode. On the contrary, the movable electrode
When tilted to the side of the electret (downward), the electrostatic force of the electret overcomes the electrostatic force of the + electret, so that torque acts on the movable electrode to tilt toward the side of the electret.

If a positive voltage is applied to the movable side drive electrode,
+ Repulsive force between the electret and the movable side drive electrode,
-A suction force is generated between the electret and the movable-side drive electrode, and a strong torque that combines the repulsive force that tilts the movable plate toward the electret side and the suction force is applied to the movable plate. If a negative voltage is applied to the movable side drive electrode, a repulsive force is generated between the − electret and the movable side drive electrode, and a suction force is generated between the + electret and the movable side drive electrode, so that the movable plate is moved to the + electret side. A strong torque that combines the repulsive force to tilt and the attractive force is applied to the movable plate.

On the other hand, the spring force supporting the movable plate is 0 at the neutral position in the parallel state, and when either side is inclined, a torque acts to return to the neutral position. That is, the electrostatic force and the spring force are applied in opposite directions. From FIG. 6, when the movable plate is tilted toward one of the electrets with the electric potentials of both drive electrodes being equal, if the electrostatic force is set to be larger than the spring force, the movable plate will be It will keep that position and will not return to the neutral position. For example, first, when a positive voltage is applied to the movable side drive electrode from a state where the + electret is tilted to the (up) side, +
Displacement tilting from the side of the electret to the (lower) side of the electret occurs, and this state is maintained even if the positive voltage is removed. The reverse operation occurs when a negative voltage is applied to the movable side drive electrode. In other words, the double mode is possible.

FIG. 7 shows that the electrets having different polarities have different absolute values of the charge amount (+ the electret is large).
In this case, the relationship between the distance (travel) between both drive electrodes, the electrostatic force (torque applied to the movable side drive electrode), and the spring load is shown. However, although the electrostatic force and the torque due to the spring load act in opposite directions, they are shown in the same direction in FIG. 7 for convenience.

If the electric potentials of both drive electrodes are equal, the electrostatic force by the + electret becomes large, so that the movable side drive electrode is stable in a state of being inclined to the + electret side. When a positive voltage is applied to the movable side drive electrode in a state of being tilted to the + electret side (upper side), a displacement that tilts from the + electret side to the − electret side (lower side) occurs. Then, when the applied voltage is removed, the restoring force of the spring is large as shown in FIG. 7, so that the spring returns to the + electret side state after passing through the neutral position. In other words, the single mode is possible.

[0025]

Embodiments of the electrostatic relay according to the present invention will be described below. The present invention is not limited to the embodiments described below. FIG. 1 shows a main configuration of an electrostatic relay according to an embodiment. FIG. 2 shows a lower fixed side base body of the electrostatic relay of the embodiment, and FIG. 3 shows a movable side base body of the electrostatic relay of the embodiment.

The electrostatic relay 1 comprises a lower fixed side base body 2a, an upper fixed side base body 2b and a movable side base body 3. The movable base body 3 is assembled so as to be sandwiched between the upper and lower fixed base bodies 2a and 2b. Each base uses a silicon single crystal substrate. When the fixed-side base body and the movable-side base body are made of the same material, they have the same thermal expansion coefficient, so that they are stable against temperature changes without being like bimetal. Fixed side base 2
And the movable side substrate 3 are made of metal layers 25, 26 of gold or gold alloy.
Are mechanically and electrically coupled. Metal layer 2
When 5 and 26 are overlapped and heated while applying an appropriate pressure, the gold alloy is eutectic and joined.

The lower fixed side base body 2a has a fixed contact 21 and a fixed side drive electrode 11. The fixed contact 21 and the fixed side drive electrode 11 are formed on the insulating film 10 on the surface of the fixed side base body 2a. The upper fixed-side base body 2b has only the fixed-side drive electrode 11 and does not have a fixed contact. The fixed side drive electrode 11 is also formed on the insulating film 10 on the surface of the upper fixed side base body 2b.

On the other hand, the movable base 3 has a movable plate 13 which also serves as a movable drive electrode and a support portion (frame portion) 12, and the movable plate 13 is attached to the support portion 12 so as to be vertically displaceable at one end. It is supported. The movable-side substrate 3 is formed by subjecting the silicon single crystal substrate to anisotropic etching or the like from the periphery to form a groove 16 or a recess in the region of the movable plate 13 facing the fixed-side substrate 2 to secure a contact gap. It is made by doing things.

A movable contact 2 is provided at the lower end of the movable plate 13.
2 is formed at a position facing the fixed contact 21 via the insulating film 14. That is, the electrostatic relay 1 has only one set of the fixed contact 21 and the movable contact 22. Of course, a movable contact is provided on the upper end of the movable plate 13, and a fixed contact is provided on the upper fixed side base body 2b.
There may be pairs.

The movable side drive electrode and the fixed side drive electrode 11 which are also served by the movable plate 13 are provided so as to face each other, and the electret 8 is provided on the lower fixed side drive electrode 11 and the upper side. A + electret 9 is provided on the left side on the fixed side drive electrode 11. For necessary electrical connection to the outside, the movable side base body 3 is partially cut away in the fixed side base body 2b, and for example, the fixed side drive electrode terminal 11a or the movable side drive electrode terminal 29 is provided. Since the terminal 28 for connecting with is protruding at the end, it is realized by wire bonding here. There is also a method of exposing the terminals by reducing the size of the periphery of the substrate to be overlaid, but each substrate is first cut out and then bonded one by one. On the other hand, in the case of the embodiment, since the wafer in which a large number of fixed-side bases are formed and the wafer in which a large number of movable-side bases are formed are joined and separated, the manufacturing efficiency is good.

4 shows a state in which the movable side base body 3 is joined to the lower fixed side base body 2a as viewed from the movable side base body 3 side, and FIG. 5 further shows the upper fixed side base body 2b as a movable side base body. 3 shows a state of being joined to No. 3 as viewed from the upper fixed side base body 2b side. Further, since the lower fixed side base body and the upper fixed side base body are silicon single crystal substrates, it is easy to form both or both of the discharge circuit and the booster circuit on the fixed side base body. Is. For example, if it has a built-in booster circuit, it can be driven with a low signal voltage.

In addition, since the impurity doping step is carried out when the driving circuit portion is formed, if the doping region 36 for the fixed side driving electrode is then formed in the surface portion of the silicon single crystal substrate for the base, the fixed portion is fixed. It is possible to save the trouble of forming the side drive electrode later.

[0033]

As described above, in the electrostatic relay of the present invention, electrets having different polarities are arranged,
When a drive voltage is applied, the electrostatic force of both electrets moves to move the movable plate.In the case of an electret, there is a small and sufficiently powerful one that raises the drive voltage or reduces the gap between contacts. Even without doing so, it is possible to easily secure the necessary and sufficient electrostatic force, and it is possible to easily take various modes, and compared with the structure in which the movable plate performs a seesaw motion with central support,
Since the structure is simple and the size can be easily reduced, it is realistic and highly practical.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a configuration of a main part of an electrostatic relay according to an embodiment.

FIG. 2 is a plan view showing a contact forming surface of a lower fixed side base body of the electrostatic relay of the embodiment.

FIG. 3 is a plan view showing a contact forming surface of the movable side base of the electrostatic relay of the embodiment.

FIG. 4 is a plan view showing a state in which a movable base body is joined to a lower fixed base body of the electrostatic relay according to the embodiment as viewed from the movable base body side.

FIG. 5 is a plan view showing a state in which a lower fixed side base body, a movable side base body, and an upper fixed side base body of the electrostatic relay of the embodiment are joined, as viewed from the upper fixed side base body side.

FIG. 6 is a graph showing the relationship between the distance between both movable and fixed drive electrodes and electrostatic force and spring load.

FIG. 7 is a graph showing a relationship between a distance between both movable and fixed drive electrodes and electrostatic force and spring load in a single mode configuration.

FIG. 8 is a partially cutaway perspective view showing a main part configuration of a conventional electrostatic relay.

FIG. 9 is an exploded perspective view showing a main part configuration of another conventional electrostatic relay.

[Explanation of symbols]

1 electrostatic relay 2a Lower fixed side substrate 2b Upper fixed side substrate 3 Movable side substrate 8 electrets 9 electret 11 Fixed side drive electrode 13 movable plate 21 Fixed contact 22 Moving contact

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hiromi Nishimura             1048, Kadoma, Kadoma-shi, Osaka Matsushita Electric Works Co., Ltd.             Inside the company (72) Inventor Fumihiro Kasano             1048, Kadoma, Kadoma-shi, Osaka Matsushita Electric Works Co., Ltd.             Inside the company (72) Inventor Takayoshi Awai             1048, Kadoma, Kadoma-shi, Osaka Matsushita Electric Works Co., Ltd.             Inside the company

Claims (6)

[Claims] 1. A fixed-side base having a fixed contact and a fixed-side drive electrode, and a movable plate having a movable contact and a movable-side drive electrode, wherein the movable plate faces the fixed-side base in the approaching and separating directions. The fixed contact is supported at one end so as to be displaceable, the fixed contact faces the movable contact, the fixed side drive electrode faces the movable side drive electrode, and both sides of the movable plate have different polarities on the front side. Are arranged so as to face each other, and the displacement of the movable plate is caused by the voltage application to the drive electrode. 2. The electrostatic relay according to claim 1, wherein fixed side drive electrodes are arranged on both sides of the movable plate, and each electret is provided on each fixed side drive electrode. 3. The movable plate itself also serves as a movable side drive electrode, an insulating film is provided on the surface of the movable plate, and a movable contact is formed on the insulating film.
The described electrostatic relay. 4. The fixed-side substrate is provided with an insulating film on the surface thereof, and the fixed-side drive electrode and the fixed contact are formed on the insulating film. Electrostatic relay. 5. The electrostatic relay according to claim 1, wherein a drive circuit portion is provided on the fixed side base body. 6. The method according to claim 1, wherein the movable plate is attracted to the electret on one side when the drive voltage is not applied, and the movable plate is attracted to the other electret only while the drive voltage is applied. The described electrostatic relay.