JPH052976A - Electrostatic relay - Google Patents

Abstract

PURPOSE:To accomplish an electrostatic relay standing influence of external magnetic field and thermal shocks and enhance the accuracy of a gap between driving electrodes by forming at least either of electroconductive bases on the movable side and stationary side in the form of a semiconductive base board, and using its counter- electroconductive type impurity high-concentration region as driving electrode. CONSTITUTION:An electrostatic relay concerned 1 includes a movable side base A and a stationary side base B both made of electroconductive material, so that the difference in the coefficient of thermal expansion is small, and stress and strain generated when thermal shock is applied can be reduced. Further, the section between these bases A, B is shielded electrically, and influence of external electromagnetic field can be reduced. At least one of the bases B is embodied in the form of a semiconductive base board. and the obtained counter-electroconductive impurity high- concentration region serves as one driving electrode 22 and confronts a movable plate 12 which is the driving electrode for the other base A. Accordingly there is no need for installnig driving electrodes on an insulative film 21 over the surface of the bases, which enhances the accuracy of the gap between the driving electrodes to lead to obtain a stable driving force.

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 An electrostatic relay, unlike an electromagnetic relay, does not require an electromagnetic coil and can be further miniaturized.
Development is actively progressing. A device size of 10 mm □ or less is possible. 12 and 13 show a conventional electrostatic relay. In this electrostatic relay 191, the movable contact 194 provided on the back side of the movable base A and the fixed contact 197 provided on the front side of the fixed base B face each other so that the movable base A and the fixed base B are opposed to each other. Are arranged. The two bases A and B are joined via a spacer C.

The movable base A has a movable plate (movable portion) 192 having a movable contact 194 on its back surface, and a support portion (frame portion) for movably supporting the movable plate 192 such that the movable contact 194 and the fixed contact 197 come into contact with and separate from each other. ) 193. Then, the movable plate 192 approaches the fixed-side substrate B by an electrostatic force generated by applying a drive voltage between the movable plate 192 which also serves as the drive electrode of the movable-side substrate A and the drive electrode 198 of the fixed-side substrate B, and both of them are moved. The contacts 194 and 197 contact each other, and the movable plate 192 restores to its original horizontal state by its own spring property as the electrostatic force disappears, and thus the movable plate 192 moves away from the fixed side base B and the contacts 19
4,197 are separated.

The movable base A is formed with a necessary structural portion by processing a silicon substrate by a fine processing means such as selective etching, while the fixed side base B is a glass substrate. The movable contact 194, the fixed contact 197, or the fixed side drive electrode 198 is formed by forming a metal thin film, patterning, or the like.

[0005]

As can be seen from the above structure and operation, the electrostatic relay can be manufactured by utilizing the semiconductor element manufacturing technology such as the photolithography technology and the microfabrication technology. , Very small size can be manufactured, the volume can be reduced to 1/10 or less compared to the conventional electromagnetic relay, high speed operation is possible, heat generation during use is very small, and the cost is low. There are advantages such as mass production.

However, the above electrostatic relay has a problem that it is easily affected by an external electromagnetic field and that it is weak against thermal shock. In the electrostatic relay described above, since the glass substrate of the fixed side base B is an insulating material, when the electrostatic relay is placed in a field strongly influenced by electromagnetic induction from the outside or a field of a strong electric field, static electricity due to a driving voltage is applied. The power fluctuates and malfunctions.

Further, the silicon substrate of the movable base A and the glass substrate of the fixed base B have greatly different coefficients of thermal expansion, and the difference in dimensional variation between the bases A and B upon thermal shock is large. Large strains and stresses are generated, which causes damage. In addition, in the conventional electrostatic relay, there is a problem that the gap error between the drive electrodes is large and the variation of the electrostatic force for driving which is proportional to the gap amount is large. If the electrostatic force is not constant, stable driving force cannot be obtained and normal operation cannot be expected. Conventionally, at least one drive electrode is formed on the insulating film on the surface of the substrate, and the accuracy of the thickness of the insulating film and the accuracy of the thickness of the metal film for the drive electrode are not very high. It does not rise.

In view of the above circumstances, it is an object of the present invention to provide an electrostatic relay that is not easily affected by an external electromagnetic field, is resistant to thermal shock, and can improve the accuracy of the gap between drive electrodes. To do.

[0009]

In order to solve the above-mentioned problems, the electrostatic relay according to the present invention has a movable contact provided on the back side of the movable base and a fixed contact provided on the front side of the fixed base. The movable side base body and the fixed side base body are arranged so that the contacts face each other, and the movable side base body has a movable part having the movable contact point on the back surface, and the movable part has a movable contact point and a fixed contact point that can be displaced. An electrostatic relay having a supporting portion for supporting the electric field, and the movable portion being displaced by the electrostatic force generated by applying a driving voltage to the driving electrodes of the both bases to bring the contacts into and out of contact with each other. In, both the movable side base body and the fixed side base body are made of a conductive material,
At least one of the bases is made of a semiconductor substrate, and the opposite conductivity type impurity high concentration region formed in the semiconductor substrate is used as one drive electrode.

As the substrate made of a conductive material, for example, a silicon substrate may be mentioned. Further, as a preferred embodiment, as in claim 3, a mode in which a portion of the semiconductor substrate other than the high-concentration region of the opposite conductivity type impurity and another substrate are electrically connected and have the same potential, As described above, in the semiconductor substrate, a high-concentration reverse-conductivity-type impurity region for the guard ring region (a conductivity type opposite to that of the semiconductor substrate) is provided on a side of the reverse-conductivity-type high-concentration region for the drive electrode.
Is formed. The guard ring area may be single, but is preferably multiple.

Further, as an example of a mode for enhancing the utilization of the electrostatic relay, a mode in which a driving circuit unit is provided on the movable side base body and / or the fixed side base body as in claim 5 or in claim 6 is adopted. As described above, there is a mode in which the electret for increasing the electrostatic force is provided between the movable side drive electrode and the fixed side drive electrode. In the case of an electrostatic relay, the drive voltage for obtaining the necessary electrostatic force is high (usually several tens of volts).
It is difficult to use because it is up to several hundreds of V), and it is desired to reduce the driving voltage. Since the signal voltage of an ordinary electronic circuit is about several V to several tens of V, a booster circuit is required. The lowering of the driving voltage causes the external circuit to be unnecessary or reduced.

In addition, the conventional electrostatic relay operates by an electrostatic force (Coulomb force) generated by a drive voltage applied between the two drive electrodes on the movable side and the fixed side, but a sufficient contact pressure is required. In order to ensure the above, the distance between both drive electrodes is shortened. This is because the electrostatic force is inversely proportional to the square of the distance between both drive electrodes, while the contact pressure is proportional to the electrostatic force. However, because the distance between both drive electrodes is short,
The breakdown voltage between the contacts is inevitably low.

The adoption of the electret brings about a reduction in driving voltage and an improvement in breakdown voltage between contacts. The electret includes, but is not limited to, an insulator having positive and / or negative charges and holding a charge whose sum is not zero. Various materials and thicknesses can be used for the electret. For example, a polypropylene having a thickness of 5 μm and charged by corona discharge is exemplified.

As mentioned above, in the case of an electrostatic relay, normally,
Since a driving voltage of several tens V to several hundreds V is required, a booster circuit for generating the driving voltage is required. Further, after the drive voltage is released, the contacts do not open unless the electric charge accumulated between the drive electrodes is discharged, and therefore a discharge circuit is usually required. Even though the electrostatic relay itself is small, it is difficult to use because it is necessary to add external circuits such as a booster circuit and a discharge circuit.
Mounting the drive circuit unit on the base body reduces the addition of an external circuit.

Specific examples of the driving circuit section include a mode having a discharge circuit and a mode having at least a part of the drive voltage generating booster circuit. The driving circuit unit does not have to include all circuits necessary for driving, and may have only some circuits. For example, there is a mode in which a part of the booster circuit and the discharge circuit are included. Of course, a mode in which all circuits necessary for driving are included is desirable. The driving circuit unit may be provided on either the movable side base body or the fixed side base body, or may be divided and provided on both base bodies.

Next, a specific example of the structure of the driving circuit section will be described. As shown in FIG. 9, the driving circuit section usually includes a booster circuit and a discharge circuit, and a signal voltage is boosted by the booster circuit and applied as a drive voltage between the movable side drive electrode 16 and the fixed side drive electrode 22. To be done. It goes without saying that the discharge circuit does not perform the discharge operation when the drive voltage is applied. When the drive voltage application is stopped, the discharge circuit quickly discharges the electric charge accumulated between the drive electrodes 16 and 22.

A more specific circuit example of the driving circuit section is shown in FIG.
It shows in 0. In the case of FIG. 10, a light emitting diode (light emitting element)
100 and a photocell array 101 in which a plurality of photovoltaic cells 102 ... Which generate electromotive force in response to light from the light emitting diode 100 are connected in series constitutes a booster circuit, which includes a normally-off NPN transistor 103 and a resistor 104.
The diode 105 constitutes a discharge circuit.

The operation of the driving circuit section shown in FIG. 10 is as follows. When the light emitting diode 100 emits light with a low signal voltage, a driving voltage higher than the signal voltage is generated in the photo cell array 101. The number of photovoltaic cells 102 is adjusted so that the required voltage level can be obtained. During the generation of the drive voltage, the transistor 103 is in the off state, and the drive voltage is normally applied between the drive electrodes 16 and 22 to be charged. When the signal voltage disappears, the drive voltage disappears,
The transistor 103 is turned on by the voltage due to the charge accumulated between the drive electrodes 16 and 22, and the discharge of the charge starts.

The drive circuit section is not limited to the above. For example, as the booster circuit, a charge pump type circuit in which n diodes and n capacitors are connected in series and parallel, or a thin film transformer type rectifier booster circuit in which a thin film transformer and a rectifying unit of a diode and a capacitor are combined can be used. However,
These booster circuits receive an AC signal voltage as an input.

[0020]

In the electrostatic relay of the present invention, both the movable side base body and the fixed side base body are conductive materials. Therefore, the difference in the coefficient of thermal expansion is small and the strain and stress that occurs when a thermal shock is applied is small, so it is strong against thermal shock, and the section sandwiched between both conductive substrates becomes an electrical shield section. The influence of the electromagnetic field is reduced, and malfunction due to external factors hardly occurs.

At least one of the bases is made of a semiconductor substrate, and the opposite conductivity type high-concentration impurity region formed in the semiconductor substrate serves as one drive electrode. Therefore, for example, if the other base itself is used as the other drive electrode, it is not necessary to provide the drive electrode on the insulating film on the surface of the base. As a result, the accuracy of the gap between the drive electrodes can be improved, and a stable driving force can be obtained. The opposite conductivity type impurity high concentration region of one drive electrode is surrounded by a conductive portion other than the other drive electrode and the electrode of the semiconductor substrate and electrically shielded,
The effect reduction effect of the external electromagnetic field is not impaired.

If both the movable side base body and the fixed side base body are silicon substrates, both base bodies have the same coefficient of thermal expansion, so that the strain and the stress upon receiving the thermal shock are extremely small, so that the thermal shock is prevented. Becomes significantly stronger. Further, in the case of a silicon substrate, it can also be used to fabricate elements such as transistors and resistors for the driving circuit section. It is possible to make the whole size including the drive circuit extremely small.

When the movable side base and the fixed side base are at the same potential, a state in which no electric field is applied between the bases is surely maintained, so that the stability is very high. If the reverse conductivity type impurity high-concentration region for the guard ring region is located at the side of the reverse conductivity type impurity high-concentration region for the drive electrode, there is an advantage that the withstand voltage of the drive electrode using the high impurity concentration region becomes high. . Both impurity high-concentration regions can be formed simultaneously.

Further, if the drive circuit portion is provided on the base, the addition of an external circuit is not necessary or reduced by that much, which facilitates the use. Further, since there is an electret between the fixed-side drive electrode and the movable-side drive electrode, and the electrostatic force increases, the drive voltage can be lowered or the contact gap can be increased by that amount to improve the breakdown voltage between contacts. The contact pressure can be increased if the drive voltage and the contact gap remain unchanged.

[0025]

Embodiments of the present invention will be described in detail below with reference to the drawings. It goes without saying that the present invention is not limited to the following embodiments. -Example 1- FIG. 1 illustrates a main configuration of an electrostatic relay according to Example 1. FIG. 2 shows a state where the entire electrostatic relay of the first embodiment is viewed from above. FIG. 3 shows an X-X cross section of FIG.

In the electrostatic relay 1 of the first embodiment, the movable contact 2 provided on the back side of the movable base A and the fixed contact 3 provided on the front side of the fixed base B face each other so that the two bases A are connected to each other. , B are arranged. The two bases A and B are joined to each other so that electrical continuity can be established at the joint surface D. In this case, after forming an alloy layer of gold and silicon on the joint surface,
A gold eutectic method was used in which the two substrates were bonded by thermocompression bonding.
Although other bonding methods are available, when a bonding method that does not allow electrical conduction is used, the substrates A and B are subjected to a treatment for electrical conduction after the bonding.

The movable base A has a movable plate (movable portion) 12 having a movable contact 2 on its back surface, and a support portion (frame portion) for movably supporting the movable plate 12 such that the movable contact 2 and the fixed contact 3 come into contact with and separate from each other. ) 13. The movable plate 12 is connected to the supporting portion 13 by the T-shaped connecting portion 14 to realize a displaceable supporting state. The movable plate 12 has, for example, a thickness of 30 μm, and is at a position slightly recessed from the bottom of the support portion 13, for example, at a position retracted by 20 μm.

The movable side substrate A is composed of a silicon single crystal substrate having a (100) surface on its surface. The above structure is relatively easy by using an aqueous potassium hydroxide etchant and a silicon nitride film as a mask material. Can be made into An insulating film 15 is formed on the back surface of the movable plate 12 (the surface on the side of the fixed base B). A movable contact 2 made of a metal thin film is patterned on the tip end region of the insulating film 15.

The fixed side substrate B is made of a p-type silicon single crystal substrate, an insulating film 21 is formed at a position facing the movable plate 12, and a fixed contact 3 made of a metal thin film is provided at a tip end region of the insulating film 21. It is patterned. Of course, the fixed contact 3 is formed in a pattern facing the movable contact 2. At the tip of the fixed contact 3, connection terminals 30, 30 are provided, respectively. Further, as shown in FIG.
A part of the bottom of 3 is recessed by, for example, about 20 μm so that the connection line of the fixed contact 3 and the support portion 13 do not come into contact with each other.

In the movable base A, the movable plate 12 serves as a movable drive electrode. The substrate itself also serves as the drive electrode. The drive voltage is introduced from the introduction terminal 19. In this case, there is an advantage that the formation of the metal pattern for the movable-side drive electrode and the formation of the absolute coating can be omitted. In the fixed-side substrate B, the reverse-conductivity-type impurity high-concentration region (impurity-doped region) on the surface portion is the fixed-side drive electrode 22. The surface of the drive electrode 22 is covered with the insulating film 21, and a window of the insulating film 21 is opened at the position of the tip of the connection line 22 a, and the window is in contact with the introduction terminal 25. It goes without saying that the driving voltage is applied between the terminals 19 and 25. The fixed side drive electrode 2
An opposite conductivity type high impurity concentration region 24 for a guard ring is also formed on the side of 2.

The contacts 2 and 3, the insulating films 15 and 21, the introduction terminals 19 and 25, and the drive electrode 22 can be formed by a well-known thin film forming process, semiconductor process, photolithography technique, or the like. Moreover, various materials can be selected according to the purpose. The contacts 2 and 3 and a gold thin film having a thickness of 0.5 μm formed by a vacuum evaporation method are patterned by a photolithography technique. The insulating film 15 has a normal pressure CV.
A silicon oxide thin film having a thickness of 1 μm was deposited by the D method and patterned by the photolithography technique. The insulating film 21 is formed by depositing a silicon oxide thin film having a thickness of 1 μm by a thermal oxidation method and patterning it by a photolithography technique. The terminals 19 and 25 have a thickness of 1 μm formed by the vacuum deposition method.
The metal (for example, aluminum) thin film is patterned by photolithography technique. Drive electrode 22
The impurity high-concentration region for use is a phosphorus-doped single-crystal substrate with a phosphorus concentration of 5 × 10 ¹⁴ / cm ³ and a diffusion depth of about 10 μm.
This is an n-type impurity region formed by doping with μm.

The non-driving electrode regions of the movable side base A and the fixed side base B are electrically connected and have the same potential, and the electric shield is sufficient. In the electrostatic relay 1 of this embodiment, it is necessary to apply the drive voltage in the direction in which the fixed-side drive electrode is positive. The pn junction in the p-type silicon single crystal substrate has a reverse bias. -Example 2- FIG. 4 illustrates a main part configuration of an electrostatic relay according to Example 2. FIG. 5 shows a state where the entire electrostatic relay of the second embodiment is viewed from above.

The electrostatic relay 1 of the second embodiment is similar to the electrostatic relay 1 of the first embodiment except that the drive electrode movable portion 12 and the drive electrode 2 are different from each other.
The electret 8 is added between the two. Figure 5
As can be seen from the above, the electret 8 having a size substantially equal to that of the drive electrode is stacked on the insulating film 21 so as to face the drive electrode. The components with the same numbers as those in the first embodiment are the same as those in the first embodiment, and the description thereof will be omitted.

However, the movable plate 12 has a thickness of 30 μm and is retracted from the bottom of the support 13 by 50 μm, and a part of the bottom of the support 13 is recessed by 50 μm so that the connection line of the fixed contact 3 is formed. It does not come into contact with the support portion 13. The electret 8 of Example 2 has a relative dielectric constant of about 2 and is polypropylene and has a thickness of 5 μm.
The electric charge held in the electret 8 is selected according to the operation state given to the relay. In the case of the second embodiment, the movable side drive electrode 16 side of the electret 8 is negatively charged and the opposite side is positively charged. And the total amount of these charges is 0
I am trying to become. There are various charging methods, but in this case, corona discharge is used.

Electret 8 thus formed
The electrostatic relay 1 using is operated in a single mode so that the contacts 2 and 3 are stable when the drive voltage is not applied (applied voltage 0), and the movable side drive electrode has a positive voltage. When the drive voltage is applied, the contacts are closed. It goes without saying that the electrostatic force is increased by the presence of the electret 8.

The strengthening of the electrostatic force will be specifically described based on a simple model. As shown in FIG. 11, the configuration around the drive electrode and the electret of the electrostatic relay is such that two electrodes a and b are arranged with a space (d ₁ + d ₂ ) therebetween.
Is approximated with the electret c having the thickness d ₂ placed on However, ε ₁ is the permittivity of air, and ε ₂ is the permittivity of the electret c. σ _{1 and} σ ₂ are the surface charges of the electret.

If there is no electret c, d ₂
As = 0, the force Fx acting on the electrode a is _{Fx = -ε 1 A (V /} d 1) 2/2 [where: A-is the area of the electrode and the electret]
Becomes On the other hand, when there is an electret c, the electrode a
Force acting on Fy is, Fy = -ε ₁ A [(Va-V) / L] a ^2/2. Here, if the electret c has only surface charges, Va = σ ₂ d ₂ / ε ₂ , L = (ε ₁ d
₂ / ε ₂ ) + d ₁ , so Fy = −ε ₁ A {[(σ
₂ d ₂ / _{ε 2)} -V] / _{[(ε 1 d 2 / ε 2} ) +
d _1]} becomes ^2/2.

Further, σ ₁ + σ ₂ = 0, σ ₁ > 0, σ ₂
When <0, the ratio Fy / Fx with and without the electret c is: {[(σ ₂ d ₂ / ε ₂ ) -V] d ₁ / [(ε ₁ d ₂ / ε ₂ ) + d ₁ ] Since V} ² = {[(σ ₂ d ₂ / ε ₂ V) -1] / [(ε ₁ d ₂ / ε ₂ d ₁ ) +1]]} ² , σ ₂ <0, V> 0. Then, since 1- (σ ₂ d ₂ / ε ₂ V)> (ε ₁ d ₂ / ε ₂ d ₁ ) +1, therefore, when V <−σ ₂ d ₁ / ε ₁ , the electret c is provided. The stronger the electrostatic force acting on the electrode a is when it is used.

For example, when the interelectrode gap is 30 μm and there is no electret c, Fx and the interelectrode gap are 50.
When there is an electret c having a surface charge of −5 × 10 ⁻⁴ C / m ² at μm, a thickness of 5 μm, and a relative dielectric constant of 2, Fy = −ε ₁ × A × 1.1 × when the driving voltage is 100V. 10 ¹³ ÷ 2 Fy = −ε ₁ × A × 2.6 × 10 ¹³ ÷ 2, which means that with the electret c, the force is more than twice as strong although the gap between the electrodes is larger. Therefore, when the electret c is provided, it has various advantages as described above.

Third Embodiment FIG. 6 shows the main configuration of an electrostatic relay according to the third embodiment. FIG. 7 shows a state where the electrostatic relay of the third embodiment is viewed from above. FIG. 8 shows the periphery of the drive circuit portion of the electrostatic relay of the third embodiment. This electrostatic relay 1 is shown in FIG.
This embodiment differs from the first embodiment in that the drive circuit section shown in FIG. Since the relay mechanism portion has the same configuration as that of the first embodiment, the description thereof will be omitted. However, the two substrates A and B are connected by the conductive paste, the drive electrode 22 is connected to the anode of the photodiode array 101 through the connection terminal 25, and the movable plate 12 is connected to the insulating film 21.
Terminal 18 and fixed side base B that contact the window of the
Is connected to the emitter of the transistor 103 via the non-driving electrode part of the.

Next, the drive circuit section will be described. The drive circuit section is provided centering on one side of the fixed-side base body B. The drive circuit unit includes a booster circuit and a discharge circuit. The booster circuit is composed of a red light emitting diode 100 and a photo cell array 101 in which a large number of photovoltaic cells 102 ... Which generate electromotive force by receiving light from the light emitting diode 100 are connected in series. Each photovoltaic cell 102
Has a tandem structure in which three pin type amorphous silicon photovoltaic cells are stacked, and 30 cells are connected in this photo cell array. The discharge circuit is composed of a normally-off NPN transistor 103, a resistor 104, and a diode (or diode array) 105. Since the operation of the circuit is as described above, the description thereof will be omitted. The light emitting diode 100 can be stacked on the photo cell array 101, for example, with a translucent insulating film interposed therebetween, or can be arranged with a space. Further, only the light emitting diode 100 may be externally attached. In this case, only a part of the booster circuit is built-in.

In the case of the electrostatic relay 1 of the third embodiment, it is possible to form the opposite conductivity type impurity high concentration region for the drive electrode at the same time in the step of forming the drive circuit section. Finally, the operation of the electrostatic relay will be described. In the case of the electrostatic relays of Examples 1 and 2, when the driving voltage is applied between the introduction terminals 19 and 25, the movable plate 12 approaches the fixed-side base body B by the electrostatic force due to the driving voltage application, and the contact 2, 3 contacts. Of course, when the electrostatic force disappears, the movable plate 12 returns to the original horizontal state by its own spring property, and the contacts 2 and 3 move away from the fixed-side base body B.

In the case of the electrostatic relay of the third embodiment, when a signal voltage is applied to the light emitting diode 100, a drive voltage is generated in the photo cell array 101, which generates a movable plate 12 of the movable side base A and a fixed side base B. The transistor 103 is turned off at the same time when the voltage is applied between the drive electrodes 22, and the movable plate 12 approaches the fixed side base B by the electrostatic force due to the application of the drive voltage, and the contacts 2 and 3 come into contact with each other. When the signal voltage is not applied to the light emitting diode 100, the photo cell array 101
At the same time, the generation of the voltage is stopped, the transistor 103 is turned on, the accumulated charge is discharged, the electrostatic force disappears, and the movable plate 12 is restored to the original horizontal state by its own spring property, so that the movable plate 12 moves away from the fixed side substrate B. The contacts 2 and 3 separate.

[0044]

As described above, in the electrostatic relay according to the invention described in claims 1 to 6, since the strain and the stress upon receiving the thermal shock become small, the electrostatic relay becomes strong against the thermal shock and the external Since the influence of the electromagnetic field of is reduced, malfunction due to external factors is less likely to occur, and since the accuracy of the gap between the drive electrodes can be improved, it becomes possible to stabilize the driving force, which is very practical. It is highly likely.

In the case of the electrostatic relay according to the second aspect, since the strain and the stress upon receiving the thermal shock are extremely small, the electrostatic relay is extremely strong against the thermal shock, and the substrate is used for forming the element of the driving circuit section. Can be used as it is, and there is an advantage that the entire size including the drive circuit can be made extremely small. In the case of the electrostatic relay according to the third aspect, a state in which no electric field is applied between the two substrates is always maintained, and therefore the stability is very high.

In the case of the electrostatic relay according to the fourth aspect, the withstand voltage of the drive electrode using the high impurity concentration region is high and the practicality is high. In the case of the electrostatic relay according to the fifth aspect, since the drive circuit portion is provided on the base body, the addition of an external circuit can be omitted or reduced, which is advantageous in that it is easy to use.

In the case of the electrostatic relay according to the sixth aspect, since the electrostatic force increases due to the presence of the electret, the drive voltage can be reduced or the contact gap can be increased to improve the breakdown voltage between the contacts. It is very practical because it can be done.

[Brief description of drawings]

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

FIG. 2 is a plan view showing a state of the electrostatic relay according to the first embodiment as viewed from above.

FIG. 3 is a sectional view taken along line XX of FIG.

FIG. 4 is a cross-sectional view showing a main configuration of an electrostatic relay according to a second embodiment.

FIG. 5 is a plan view showing a state of the electrostatic relay according to the second embodiment as viewed from above.

FIG. 6 is a cross-sectional view showing a configuration of a main part of an electrostatic relay according to a third embodiment.

FIG. 7 is a plan view showing a state of an electrostatic relay according to a third embodiment as viewed from above.

FIG. 8 is a plan view showing details of a drive circuit portion of an electrostatic relay according to a third embodiment.

FIG. 9 is a block diagram showing a configuration example of a driving circuit portion of the electrostatic relay of the present invention.

FIG. 10 is a circuit diagram showing a specific configuration example of a driving circuit unit of the electrostatic relay of the present invention.

FIG. 11 is a schematic cross-sectional view showing a model configuration around a drive electrode and an electret of an electrostatic relay.

FIG. 12 is a plan view showing a conventional electrostatic relay.

FIG. 13 is a cross-sectional view showing a conventional electrostatic relay.

[Explanation of symbols]

1 electrostatic relay 2 movable contacts 3 fixed contacts 8 electrets 12 Moving part 13 Support 22 Fixed side drive electrode (reverse conductivity type impurity high concentration region) A movable base B Fixed side substrate

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[Procedure amendment]

[Submission date] September 11, 1991

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0019

[Correction method] Change

[Correction content]

The drive circuit section is not limited to the above. For example, as the booster circuit, a charge pump type circuit in which n diodes and n capacitors are connected in series and parallel, or a thin film transformer type rectifier booster circuit in which a thin film transformer and a rectifying unit of a diode and a capacitor are combined can be used.

   ─────────────────────────────────────────────────── ─── 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. The movable side base and the fixed side base are arranged so that the movable contact provided on the back side of the movable side base and the fixed contact provided on the front side of the fixed side base face each other, and the movable side. The base body includes a movable portion having the movable contact on the back surface and a support portion that movably supports the movable portion such that the movable contact and the fixed contact come in contact with each other. By applying a drive voltage to the drive electrodes of both the base bodies, In an electrostatic relay in which the movable portion is displaced by the generated electrostatic force to bring the contacts into and out of contact, at least one of the movable side base body and the fixed side base body is made of a conductive material. The base body is made of a semiconductor substrate, and the opposite conductivity type high-concentration impurity region formed on the semiconductor substrate serves as one of the drive electrodes. 2. The electrostatic relay according to claim 1, wherein the movable side base body and the fixed side base body are silicon substrates. 3. The electrostatic relay according to claim 1 or 2, wherein a portion of the semiconductor substrate other than the high-concentration region of the opposite conductivity type impurity is electrically connected to another substrate to have the same potential. 4. The semiconductor substrate is provided with an opposite conductivity type impurity high concentration region for the guard ring region formed at a position lateral to the opposite conductivity type impurity high concentration region for the drive electrode. The electrostatic relay according to any one. 5. The electrostatic relay according to claim 1, wherein a drive circuit section is provided on the movable side base body and / or the fixed side base body. 6. The electrostatic relay according to claim 1, wherein an electret for increasing electrostatic force is provided between the movable side drive electrode and the fixed side drive electrode.