JPH0745175A - Electrostatic relay - Google Patents

Abstract

PURPOSE:To eliminate breakage of a support end part by vibration or impact, and make metal function also as a mask material by sticking the metal on a movable piece composed of a silicon wafer, and constituting at least the periphery of the support end part of the movable piece only of the metal. CONSTITUTION:Both latching operation and single operation are made possible by changing a balance of an electrification quantity between two electrets 17 and 18. The void between fixed electrodes 10 and 11 opposing to each other over a central part from a support end part 9 of a movable electrode 4, is made smaller than the void between the free end side of the electrode 4 and electrodes 10 and 11 by step differences 27 and 28, and large force is obtained by using force obtained by superimposing electrostatic force acting on the electrode 4 by the electrets 17 and 18 on electrostatic force by external impression voltage, and contact point pressure is increased. A magnetic field is generated between an upper fixed piece 1, a magnetic substance 15 and the movable electrode 4 or a magnetic substance 16 of a lower fixed piece 3 and the electrode 4 by flowing an exciting current to coils 13a and 13b from separate electric power supply E2 through a chageover switch SW, and electrostatic force is added also to electromagnetic force.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an electrostatic relay driven by at least electrostatic force.

[0002]

2. Description of the Related Art Known examples of conventional electrostatic relays include those disclosed in Japanese Examined Patent Publication (Kokoku) No. 55-15060 and Japanese Patent Laid-Open No. 2-100224, the former of which is fixed in parallel as shown in FIG. Electret 4 between the electrodes 40, 40
2 has a movable piece 41 formed therein.
In the latter case, the fixed electrode 40 is formed on the substrate 43 that constitutes the fixed piece as shown in FIG.
The movable piece 41 is arranged so as to be parallel to the above.

[0003]

Further, in the construction of the above-mentioned conventional example, since the whole movable part is made of silicon, it is fragile. Especially, in the latter conventional example, the supporting end portion which is the central fulcrum is not susceptible to vibration and impact. There was a problem that it was weak and easily broken during the manufacturing process. The present invention has been made in view of the above problems, and an object of the present invention is to provide an electrostatic relay that is not damaged by vibration or shock from the outside or in the manufacturing process.

[0004]

In order to achieve the above-mentioned object, the present invention comprises two fixing pieces made of a silicon wafer on which a fixed electrode is formed and a silicon wafer making a movable electric power. And a movable piece in which the movable electrode is movably supported by sandwiching the movable electrode, and an electret is formed on each fixed electrode of both the fixed pieces, and the movable piece moves between the movable piece and the fixed piece. In an electrostatic relay characterized in that contacts are provided to contact and separate from each other, a metal is adhered onto a movable piece made of the above silicon wafer, and at least a periphery of a supporting end of the movable piece is made of only metal. is there.

[0005]

According to the present invention, the metal is attached on the movable piece made of a silicon wafer, and at least the periphery of the supporting end of the movable piece is made of only metal. Therefore, the supporting end is broken by vibration or impact. It is difficult to do so, and since metal can be used as a mask material, there is no waste in the manufacturing process.

[0006]

EXAMPLES The present invention will be described below with reference to examples. (Embodiment 1) In this embodiment, as shown in FIG. 1, it is composed of an upper fixed piece 1, a movable piece 2 and a lower fixed piece 3, and a movable piece 2 is sandwiched between upper and lower fixed pieces 1 and 3. It has a structure to be clamped in a shape.

As shown in FIGS. 3 and 4, the movable piece 2 is made of a silicon single crystal wafer as a base material, and has a movable electrode 4, a fixed contact terminal 5, a movable contact 6, and a fixed piece bonding metal thin film layer 7. , The electrode terminals 8 and the like are formed. The movable electrode 4 is processed into a concave portion from the upper and lower sides by anisotropic etching or the like from the peripheral portion of the movable piece 2, and the outer periphery is separated from the movable piece 2 by dry etching or the like in a U-shape to form a silicon single crystal wafer. The support end portion 9 in which the metal thin film layer 29 for a support spring made of a magnetic material formed above is integrally connected to the fixed side of the movable piece 2
The movable electrode 4 rotates about the supporting end portion 9 as a center.

Therefore, the movable electrode 4 moves with respect to the fixed electrodes 10 and 11 of the upper and lower fixed pieces 1 and 3 which will be described later. The movable contact 6 is formed on the insulating film 14 so that the gap between the contacts can be provided only by joining the two fixed pieces 1 and 3 above and below the movable piece 2 by the concave portion of the movable electrode 4. Has become. The movable portion is constituted by the portion where the movable contact 6 and the movable electrode 4 are provided.

The metal thin film layer 7 and the fixed contact terminal 5 are also provided.
Is also formed on the insulating film 14, and the metal thin film layer 7
Is made of a gold or gold alloy layer and is connected to a silicon single crystal wafer which is a base material of the movable piece 2. Like the movable piece 2, the upper and lower fixed pieces 1 and 3 are made of a silicon single crystal wafer as a base material, and as shown in FIGS. 1, 2, and 5, the fixed electrodes 10 and 11 on the silicon single crystal wafer are used. Magnetic body 15,
16, electrets 17, 18, fixed contacts 12, 1
9. Metal thin film layers 25 and 26 made of gold or a gold alloy layer for joining movable pieces are formed respectively, and the fixed electrodes 10 and 11 and the electrets 17 and 18 are connected by magnetic bodies 15 and 16. Reference numeral 23 is an electrode terminal of the fixing pieces 1 and 3.
Further, a recess is formed around the central portion, and coils 13a and 13b are formed so as to surround the central portion.

The fixed contact terminals 5 provided on the upper and lower surfaces of the movable piece 2 are fixed contacts 12 and 19 of the upper and lower fixed pieces 1 and 3, respectively.
Is a fixed contact terminal connected to. Then, the metal thin film layers 7 and 25 for joining the movable piece 2 and the upper and lower fixed pieces 1 and 3 are joined together.
And 26 are brought into contact with each other and heated while applying appropriate pressure, and the metal thin film layers for bonding 7, 25, 26 are joined.
Are eutecticized together with the base material silicon, and are mechanically and electrically connected as shown in FIG.

Further, the fixed electrodes 10 and 11 of the fixed pieces 1 and 3 facing each other from the supporting end portion 9 of the movable electrode 4 to the substantially central portion are opposed to each other from the substantially central portion of the movable electrode 4 to the free end. The surface of the portion of the fixed electrodes 10 and 11 facing the support end 9 from the intermediate portion of the movable electrode 4 is moved toward the movable electrode 4 side so that the gap with the movable electrode 4 becomes smaller than the portion of the fixed electrode 10 and 11. Steps 27 and 28 are formed on the surfaces of the fixed electrodes 10 and 11 so as to project.

Therefore, in this embodiment, the surface of the electret 17 of the upper fixed piece 1 facing the movable electrode 4 is positive,
The surface of the electret 18 of the lower fixed piece 3 facing the movable electrode 4 is permanently polarized so as to be negative.
FIG. 6 shows the relationship between the inter-electrode distance, the electrostatic force (torque applied to the movable electrode 4), and the spring load when the absolute values of the electric charges of both electrets 17 and 18 are the same. 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. In FIG. 6, a is a spring load force, b is an electrostatic force when the applied voltage is 0 V, c is an electrostatic force when a positive voltage is applied to the movable electrode 4, and d is a negative voltage to the movable electrode 4. The electrostatic force when applied is shown.

The electrostatic relay of this embodiment has fixed electrodes 10, 1
When the potentials of 1 and the movable electrode 4 are the same, the fixed electrode 10,
At the neutral position where 11 and the movable electrode 4 are parallel to each other, the electrostatic forces generated by the two electrets 17 and 18 have the same magnitude, and the torque acting on the movable electrode 4 is zero. When the movable electrode 4 tilts toward the upper electret 18, the electrostatic force generated by the upper electret 17 is large, so that a torque that tends to tilt toward the upper electret 17 is generated at the movable electrode 4. On the contrary, when the movable electrode 4 tilts toward the lower electret 18, the electrostatic force generated by the lower electret 18 is large, so that the movable electrode 4 generates a torque that tends to tilt toward the lower electret 18.

When a positive voltage is applied from the power source E ₁ to the movable electrode 4 by using the electrode terminals 8 and 23, the attraction force between the upper electret 17 and the movable electrode 4 becomes small and the movable electret 18 and the lower electret 18 move. Since a large absorbing force is generated in the electrode 4, a torque that tends to tilt toward the lower electret 18 is generated in the movable electrode 4. Conversely, when a negative voltage is applied to the movable electrode 4, a large absorption force is generated in the upper electret 17 and the movable electrode 4, and a small attraction force is generated in the lower electret 18 and the movable electrode 4, so that the upper electret 17 is applied to the movable electrode 4. A torque that tends to lean toward the side is generated.

Further, the spring force of the movable electrode 4 is 0 at the neutral position, and when the movable electrode 4 is inclined toward either electret 17 or 18, the torque for returning to the neutral position acts. That is, the electrostatic force and the spring force are applied in opposite directions. When no voltage is applied to the movable electrode 4 in FIG. 6 and the movable electrode 4 is inclined to either of the electrets 17 or 18, the electrostatic force is set to be larger than the spring force. 4 retains its position and does not return to the neutral position. That is, it has two stable states.

For example, when a positive voltage is applied to the movable electrode 4 from the state of being inclined to the upper electret 17 side at first, the attraction force to the upper electret 17 becomes weak and the lower electret 18 is rotated and held. . Even if the voltage applied to the movable electrode 4 is set to 0 in this state, the state is maintained. Conversely, when a negative voltage is applied to the movable electrode 4, the reverse operation is performed. That is, the latching operation becomes possible.

FIG. 7 shows the operation when the absolute values of the charge amounts of the two electrets 17 and 18 are different. In this illustrated example, the electrification amount of the electret 17 is set to be larger. In the state where no voltage is applied to the movable electrode 4, the attraction force from the upper portion is larger, so that the movable electrode 4 is stable when it is inclined to the upper portion. Then, when a positive voltage is applied to the movable electrode 4, the attractive force from the lower portion becomes strong, and a torque that tends to incline to the lower portion acts on the movable electrode 4 and stabilizes with the contact portion closed. Then, when the applied voltage is removed, the restoring force of the spring is superior, so the spring returns to the neutral position and returns to the original position by the suction force of the upper part. In FIG. 7, a is a spring load force, b is an electrostatic force when the applied voltage is 0, and c is an electrostatic force when a positive voltage is applied to the movable electrode 4.

Due to the above, the two electrets 17 and 1
Both the latching operation and the single operation are possible by changing the balance of the charge amount of 8. In addition, the gap between the fixed electrodes 10 and 11 facing each other from the support end 9 of the movable electrode 4 to the substantially central portion is larger than the gap between the free end side of the movable electrode 4 and the fixed electrodes 10 and 11. By using the force that is smaller due to the steps 27 and 28 and that is a combination of the electrostatic force exerted on the movable electrode 4 by the electrets 17 and 18 and the electrostatic force caused by the externally applied voltage, a large force is obtained and the contact pressure is increased. Can be taken.

Furthermore, from another power source E ₂ to the coils 13a, 13
A magnetic field is generated between the magnetic body 15 of the upper fixed piece 1 and the movable electrode 4 or the magnetic body 16 of the lower fixed piece 3 and the movable electrode 4 by causing an exciting current to flow to b through the changeover switch SW. As a result, electromagnetic force is added to the electrostatic force, so that the contact pressure can be further increased. Since the present embodiment is configured as described above, it becomes possible to bond three silicon single crystal wafers on which a large number of fixed pieces 1 and 3 and movable piece 2 are formed first, and then cut out the wafer. Efficiency is improved. Further, fixed electrodes 10 and 11 made of a high-concentration doping layer are formed on the fixing pieces 1 and 3 and an electrostatic drive circuit IC composed of a transistor, a diode, a resistance element, a capacitor, etc. is formed. Alternatively, when the drive circuit is integrally formed, it is not necessary to provide the drive circuit outside.

When operating the electrostatic relay, the applied voltage needs to be several tens of volts, but if a booster circuit is formed on the fixed pieces 1 and 3, the input operates at several volts. The movable piece 2 is shown in FIG.
It is formed by the process shown in. That is, as shown in FIG. 8B, a concave portion 32a is formed by anisotropic etching on the upper surface of the silicon single crystal wafer 31 on which the insulating film 14 made of SiO 2 is formed as shown in FIG. Recess 3
A metal thin film layer 29 for a supporting spring, which serves as a mask material for dry etching, is formed on the surface 2a, and an insulating film 14 is further formed as shown in FIG. 2C, and the movable electrode 4, the movable contact 6, and the fixed piece are formed. The metal thin film piece for connection 7 and the fixed contact terminal 5 are formed of Au. Thereafter, the movable electrode 4, the movable contact 6, the fixed piece connecting metal thin film piece 7, and the fixed contact terminal 5 are covered with a protective film 33, and a concave portion 32b is formed on the lower surface by anisotropic etching (see FIG. (D)). After that, the protective film 33 is removed (FIG. 7E). After that, the periphery of the movable electrode 4 is cut into a U-shape by dry etching such as RIE (FIG. 6F). At this time, the metal thin film layer 29 is utilized as a mask material.

The upper fixed piece 1 is formed in the process shown in FIG. That is, as shown in FIG. 9A, a silicon single crystal wafer 3 having a fixed electrode 10 made of SiO 2 formed on the surface thereof.
A step 27 is formed on the lower surface of 1 by anisotropic etching (FIG. 2B), a magnetic material 15 layer is further formed, and an insulating film 20a is formed on the magnetic material 15 layer.
The fixed electrode 10, the fixed contact 12, and the metal thin film layer 25 are formed on a by Au, and the electret 17 is further formed as shown in FIG. ), The upper fixed piece 1 is obtained.

The lower fixing piece 3 is formed by the process shown in FIG. That is, as shown in FIG. 10A, a silicon single crystal wafer 3 having a fixed electrode 11 made of SiO 2 formed on the surface thereof.
A step 28 is formed on the upper surface of No. 1 by anisotropic etching (FIG. 7B), and then the magnetic material 1 is formed on the fixed electrode 11.
Six layers are formed, an insulating film 20b is formed on the magnetic body 16, and the fixed electrode 11 is formed on the insulating film 20b by Au.
The fixed contact 19 and the metal thin film layer 26 are formed as shown in FIG. 7C, and the lower fixed piece 3 is obtained as shown in FIG.

(Embodiment 2) In Embodiment 1, the supporting spring metal thin film 29 is formed on the surface of the cantilevered movable electrode 4, and at least the vicinity of the supporting end 9 is the supporting spring metal thin film 29.
However, in the present embodiment, as shown in FIG. 11, the supporting end portion 9 made of the supporting spring metal film 29 is formed on the central axis of the movable electrode 4. Further, movable contacts 6 are formed at both ends of the movable electrode 4, and Ni is attached on the movable electrode 4.

In this embodiment as well, since the support end 9 of the movable electrode 4 is formed of the support spring metal thin film 29, when vibration or shock is applied, the part where the stress is highest is not easily damaged. . Since the other operations and characteristics of this embodiment are the same as those of the first embodiment, the description of the operation is omitted.

Further, the formation of the fixing pieces 1 and 3 is different in that the step of forming the steps 27 and 28 in the first embodiment is omitted, but the other steps are the same and the description of the forming step is also omitted. (Third Embodiment) In the second embodiment, the support spring metal thin film 2 is used.
Although the support end portion 9 is formed on the central axis of the movable electrode 4 by means of 9, the support spring metal thin film 29 is provided from the center of the movable electrode 4 to both ends of the movable piece 2 in this embodiment, as shown in FIG. The support end 9 is formed by extension.

(Embodiment 4) In Embodiment 3, the support spring metal thin film 29 is extended from the center of the movable electrode 4 to both ends of the movable piece 2 to form the support end 9. As shown in FIG. 13, the support spring metal thin film 29 is extended to the center axis of the coupling of both ends to form the support end 9. Since the operation of the movable piece 2 with respect to the fixed piece 3 is the same as the operation with respect to the lower fixed piece 3 in the first embodiment, the operation description will be omitted.

(Embodiment 5) In this embodiment, as shown in FIG. 14, a metal thin film 29 for a support spring is extended from the corner of the movable electrode 4 in a clockwise or counterclockwise direction, and the tip of the extension piece 29a is a support end. It is part 9. In the first to fifth embodiments described above, damage is prevented from occurring due to external vibrations and manufacturing vibrations and shocks, and in order to obtain a large contact pressure, the support end portion 9 that connects the movable piece 2 and the movable electrode 4 together. The metal thin film 29 for supporting springs for supporting the magnets is formed of a magnetic material, and the magnetic materials 15 and 16 layers are formed on the fixed electrodes 10 and 11 of the upper and lower fixed pieces 1 and 3, and the coils 13a and 13b are provided. By adding a system that generates an electromagnetic force by applying this electromagnetic force to an electrostatic force, it was attempted to obtain a large contact pressure.However, damage may occur simply due to external or manufacturing vibration or impact. If nothing is done, the support end 9 may be formed of at least the support spring metal thin film 29.

In the embodiment described below, the support end 9 is formed of at least a metal thin film 29 for a support spring so that the support end 9 will not be damaged by external vibration or vibration. (Embodiment 6) This embodiment is different from Embodiment 1 in coil 13a,
13b and the magnetic bodies 15 and 16 do not exist in the fixed pieces 1 and 3, and the support spring metal thin film 29 does not have to be a magnetic body. FIG. 16 is a cross-sectional view of this embodiment. ,
17 is an exploded perspective view of this embodiment, FIG. 18 is a bottom view of the movable piece 2, FIG. 19 is a bottom view of the upper fixed piece 1, and FIG. 20 is a top view of the lower fixed piece 3. However, since the structure of the present embodiment is basically the same as that of the first embodiment, the same reference numerals and symbols are given to the parts having the same structures as those of the first embodiment in the above-described embodiment drawings, and the description thereof will be omitted.

The upper and lower fixing pieces 1 and 3 are made of a silicon single crystal wafer as a base material like the first embodiment, and the insulating film 20 is used.
a, 20b on the fixed electrodes 10 and 11, the electret 1
7 and 18, fixed contacts 12 and 19, and metal thin film layers 25 and 26 made of gold or gold alloy layers for joining movable pieces, respectively, are formed, and the fixed electrodes 10 and 11 and the electrets 17 and 18 are formed.
Are connected by contacts 21 and 22.

The operation of the electrostatic relay of this embodiment is basically the same as that of the first embodiment except that the electromagnetic force is generated, and therefore the description of the operation is omitted. The steps of forming the upper and lower fixed pieces 1 and 3 and the movable piece 2 are basically the same as those in the first embodiment, and the support spring metal thin film 29 is used as a mask material as in the first embodiment. The description of the forming process is omitted.

21 to 24 show movable pieces 2 of Examples 7 to 10 corresponding to the above Examples 2 to 5, and in these Examples, a supporting end for movably supporting the movable electrode 4 is shown. The portion 9 is formed of a support spring metal thin film 29 extending from the movable electrode 4.

[0032]

According to the present invention, two fixed pieces made of a silicon single crystal wafer for forming a fixed electrode and a silicon single crystal wafer for making a movable electric power are sandwiched and sandwiched by the both fixed pieces. Is composed of a movable piece movably supported, and an electret is formed on each fixed electrode of both the fixed pieces, and the movable piece and the fixed piece are provided with contacts that come in contact with and separate from each other by the movement of the movable piece. In the electrostatic relay characterized in that the metal is attached on the movable piece made of the silicon single crystal wafer, and at least the periphery of the supporting end of the movable piece is made of only metal, so that it is resistant to vibration and shock. Even if added, the supporting end portion is less likely to be broken, and since metal can be used as a mask material, it is possible to reduce waste in the manufacturing process.

[Brief description of drawings]

FIG. 1 is a sectional view of a first embodiment of the present invention.

FIG. 2 is a bottom view of the upper fixing piece of the above.

FIG. 3 is a top view of the above movable piece.

FIG. 4 is a bottom view of the above movable piece.

FIG. 5 is a top view of the lower fixing piece of the above.

FIG. 6 is a relationship characteristic diagram between the contact distance, the electrostatic force, and the spring load for explaining the above-described operation, and is an operation characteristic diagram.

FIG. 7 is a relational diagram between the contact distance, the electrostatic force, and the spring load, which is another operation explanatory diagram, and is an operation characteristic diagram.

FIG. 8 is an explanatory diagram of a process of forming the movable piece of the above.

FIG. 9 is an explanatory diagram of a forming process of the upper fixing piece of the above.

FIG. 10 is an explanatory diagram of a forming process of the lower fixing piece of the above.

FIG. 11 is a top view of a movable piece according to a second embodiment of the present invention.

FIG. 12 is a top view of a movable piece according to a third embodiment of the present invention.

FIG. 13 is a top view of a movable piece according to a fourth embodiment of the present invention.

FIG. 14 is a top view of a movable piece according to a fifth embodiment of the present invention.

FIG. 15 is a sectional view of Embodiment 6 of the present invention.

FIG. 16 is an exploded perspective view of the above.

FIG. 17 is a top view of the above movable piece.

FIG. 18 is a bottom view of the upper fixing piece of the above.

FIG. 19 is a top view of the lower fixing piece of the above.

FIG. 20 is a top view of a movable piece according to a seventh embodiment of the present invention.

FIG. 21 is a top view of a movable piece according to Example 8 of the present invention.

FIG. 22 is a top view of a movable piece according to Example 9 of the present invention.

FIG. 23 is a top view of a movable piece according to Example 10 of the present invention.

FIG. 24 is a configuration diagram of a conventional example.

FIG. 25 is a block diagram of another conventional example.

[Explanation of symbols]

 1 Upper Fixed Piece 2 Movable Piece 3 Lower Fixed Piece 4 Movable Electrode 6 Moving Contact 9 Support End 10 Fixed Electrode 11 Fixed Electrode 12 Fixed Contact 13a Coil 13b Coil 17 Electret 18 Electret 19 Fixed Contact 27 Step 28 28 Step 29 Metal for Support Spring Thin film

Claims (1)

[Claims] 1. A movable member in which two fixed pieces made of a silicon wafer forming a fixed electrode and a silicon wafer making a movable electric power are sandwiched between the both fixed pieces and the movable electrode is movably supported. An electrostatic relay characterized in that an electret is formed on each fixed electrode of both of the fixed pieces, and a contact that comes in contact with and separates from each other by the movement of the movable piece is provided on the movable piece and the fixed piece. 2. An electrostatic relay characterized in that a metal is adhered onto a movable piece made of the above silicon wafer, and at least a periphery of a support end portion of the movable piece is made of only metal.