JP3402626B2 - Electrostatic drive type relay - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic drive type relay driven by electrostatic force.

[0002]

2. Description of the Related Art Known examples of this type of electrostatic drive type relay are Japanese Patent Publication No. 55-15060 and JP-A No. 2-10022.
No. 4 is shown, and the former one has a configuration in which an electret 41 is arranged between control electrodes 40, 40 arranged in parallel as shown in FIG. In the latter, as shown in FIG. 14, the fixed electrode layer 33 is formed on the substrate 42, and the movable piece 44 is arranged above the fixed electrode layer 43 in parallel.

[0003]

In the former configuration of the above-mentioned conventional examples, when the electret 41 is polarized and the total charge of the electret 41 is 0, it does not operate. Therefore, it is necessary to charge the polarized electric charges so that the absolute values of the electric charges are different, it is difficult to accurately control the charge amount, and it is necessary to provide a charging / discharging circuit externally. It had the drawback of becoming larger.

In the latter case, the contact pressure is weak and the contact reliability is poor because the operation is performed only by the electrostatic force generated by the voltage applied to the electrodes. In addition, in order to obtain the electrostatic force, it is necessary to reduce the distance between the electrodes or increase the voltage applied to the electrodes.By reducing the distance between the electrodes, the gap between the contacts also becomes smaller and the breakdown voltage between the contacts becomes smaller. There was a problem of becoming smaller.

Further, in this conventional example, the movable piece 44 is formed of a silicon wafer and the fixed electrode layer 43 is formed on the substrate 4.
Since No. 2 is made of resin and made of different materials, there is a problem that the coefficient of thermal expansion is different and, as a result, if the operating temperature fluctuates, the structure is distorted and the operation becomes unstable. It was The present invention has been made to solve the above problems, and the electret can be easily charged, no malfunction occurs due to external vibration or shock, sufficient contact pressure can be obtained, and contact reliability can be improved. It is also an object of the present invention to provide an electrostatic drive type relay which has good contact resistance, high withstand voltage between contacts, low applied voltage to the upper electrode, is stable against temperature change, and can be miniaturized.

[0006]

In order to achieve the above-mentioned object, the invention according to claim 1 comprises two fixed pieces made of a silicon wafer on which a fixed electrode is formed and a silicon wafer on which a movable electrode is formed. The movable electrode is sandwiched between the two fixed pieces, and the movable electrode is movably supported, and an electret is formed on each fixed electrode of the both fixed pieces. It is provided with contacts that come into contact with and separate from each other by the movement of the movable piece ,
The movable electrode is formed by etching the base material of the movable piece into a U shape.
And one end connected to the base material is used as a supporting and fixed end.
Inside the area surrounded by the ching area,
Etching in a letter shape, the center surrounded by the etching site
The central movable electrode is located between the two parts
The movable end electrodes are formed at the side peripheral portions, respectively, and
Corresponds to the fixed contact on the above-mentioned fixed side on the free end of the central part
A movable contact is provided, and the end movable electrode is connected to the support fixed end.
The central movable electrode rotates about the center,
Located on the opposite side, consisting of the proximal end of the central movable electrode
It is characterized by rotating around the fixed end that supports the central movable electrode.
And

According to a second aspect of the invention, a fixed electrode can be formed.
Two fixed pieces made of recon wafer and movable electrodes are formed
It consists of a silicon wafer that can be
It is sandwiched in a ditch shape and the movable electrode is movably supported.
It is composed of a movable piece and
An electret is formed, and the movable piece and the fixed piece are movable pieces.
It has contacts that come in and out of contact with each other when
The movable electrode is connected to the base material of the movable piece in the movable piece.
Two points at both ends are used as supporting and fixing ends, and both the above supporting and fixing inside
The center of both sides in the direction perpendicular to the line connecting the ends is different
The circumference is fixed so that it is integrally connected to the peripheral part at the support fixed end.
Forming a central movable electrode at the etched central portion,
At the peripheral part of the part where the central movable electrode is formed,
Form a pole and deform around the other support fixed end
Movable contacts are provided at both free ends of the central part.
And are characterized.

[0008]

According to the structure of the present invention, two fixed pieces made of a silicon wafer for forming fixed electrodes and a silicon wafer for forming a movable electrode are sandwiched between the two fixed pieces and sandwiched between the movable pieces. The electrode is composed of a movable piece that is movably supported, and since an electret is formed on each fixed electrode of both of the above fixed pieces, the electrostatic force exerted on the movable electrode by the electret and the electrostatic force caused by external application are superposed. Since the combined force can be used and the movable electrode can be moved in a state in which it is parallel to the fixed electrode, the electrostatic force is larger than usual, resulting in a large contact pressure and contact reliability of the contact. Is good. Also, it is unlikely to malfunction due to external vibration or shock. Further, the gap between the movable electrode and the fixed electrode can be widened, and as a result, the gap between the contacts can be increased to increase the withstand voltage between the contacts, and the voltage applied to the electrodes can be low, so that the withstand voltage of the drive circuit can be increased. Can be lowered.

Further, since both the movable piece and the fixed piece are made of silicon wafers, a large number of pieces can be manufactured at the same time on one wafer, so that mass productivity is good, and as a result, they can be manufactured at low cost and bonded. Since the movable piece and the fixed piece are made of the same material, they have the same coefficient of thermal expansion, do not move like bimetal, and are stable against temperature changes. Further, since the fixing piece is made of a silicon wafer, drive circuits such as a discharge circuit and a booster circuit can be formed on the silicon wafer, so that it is not necessary to provide an external drive device. First movable especially during operation
The end of the electrode The movable electrode is centered on the support fixed end of the movable electrode.
Center deformable electrode, and then the center movable electrode
The motion that tries to rotate around the support fixed end is obtained.
Therefore, the central movable electrode should move parallel to the fixed electrode.
Therefore, the movable electrode has a large electrostatic force with respect to the fixed electrode.
Is generated and also approaches the fixed side in parallel,
When the distance between fixed electrodes is always constant and the contact part turns on,
A piece that the gap between the center movable electrode and the fixed electrode is close to 0
A handheld relay can be realized.

[0010] According to the invention 請 Motomeko 2, during operation the ends
Both ends of the movable electrode are fixedly supported by the support fixed end, so
The movable electrode tries to deform like a bow, while the central electrode moves
The electrode is centered around another support fixed end on both sides of the center
Because of the movement to be shaped, the central movable electrode
It moves parallel to the fixed electrode, resulting in the movable electrode
Generates a large electrostatic force to the pole, especially the contact part turns on
In this case, it is possible to realize a dual-support type relay in which the gap between the central movable electrode and the fixed electrode is close to zero .

[0011]

EXAMPLES The present invention will be described below with reference to examples. (Embodiment 1) In this embodiment, as shown in FIG.
The movable piece 2 and the lower fixed piece 3 are configured so that the movable piece 2 is sandwiched between the upper and lower fixed pieces 1 and 3.

As shown in FIG. 2, the movable piece 2 is made of a silicon single crystal wafer as a base material, and includes a movable electrode 21, a fixed contact 22, a movable contact 23, a fixed piece bonding metal thin film layer 24,
The electrode terminal 28 is formed. The movable electrode 21 is the movable piece 2
The insulating film 20 is covered with the insulating film 20 which has been processed into a concave portion from above and below by anisotropic etching or the like from the peripheral portion thereof, and the outer periphery is etched and formed in a U shape, and one end thereof serves as the support fixed end 25. There is. Further, inside thereof, an end movable electrode 21a which is a peripheral portion and a central movable electrode 21b which is a central portion are formed by etching in a U shape opposite to the above U shape, and the end movable electrode 21a is , The support fixed end 2
5, the center movable electrode 21b is rotated about the center movable electrode 21b, and the center movable electrode support fixed end 26 is located on the side opposite to the support fixed end 25.
Rotate around.

Therefore, the central movable electrode 21b moves in parallel with the fixed electrodes 10 and 30 of the upper and lower fixed pieces 1 and 3 which will be described later. Further, notches 27 are provided at the corners of the movable piece 2 so that an electric signal can be taken out from the fixed contact of the lower fixed piece 3. The movable contact 23 is formed on the insulating film 20, and the concave portion of the movable electrode 21 can provide a gap between the contacts only by vertically joining the two fixed pieces 1 and 3. The metal thin film layer 24 and the fixed contact 22 are also formed on the insulating film 20,
The metal thin film layer 24 is made of gold or a gold alloy layer,
It is connected to the silicon single crystal wafer which is the base material of.
Reference numeral 28 is an electrode terminal.

Like the movable piece 2, the fixed pieces 1 and 3 are made of a silicon single crystal wafer as a base material. As shown in FIGS. 3 and 4, the fixed electrodes 10 and 30 and the electret are provided on the insulating films 14 and 34. 11, 31, fixed contacts 12, 32, metal thin film layers 13, 33 made of gold or gold alloy layers for joining movable pieces
To form the respective electrodes 10, 30 and the electret 11
Are connected by contacts 15, 35. 16
Is an electrode terminal of the upper fixed piece 1. Also 22a, 22b
Is a fixed contact terminal provided at the end of the fixed contact 22 of the movable piece 1 connected to the fixed contacts 12 and 32.

Thus, the movable metal piece 2, the upper and lower fixed metal pieces 1, 3 are brought into contact with the metal thin film layers 24 and 13 for bonding and 24 and 33 so that they are brought into contact with each other, and heated while applying an appropriate pressure. The metal thin film layers 24, 13, 33 are eutectic with each other as the base silicon, and are connected mechanically and electrically. FIG. 5 shows the movable piece 2.
FIG. 3 is a cross-sectional view showing a state in which the fixing pieces 1 and 3 are clamped.

There is also a method of exposing the electrodes by reducing the size of the periphery of the parts to be overlaid as a method of extracting the electric signal to the outside, but this requires cutting out the parts and then joining them, which complicates the process. Therefore, in the present embodiment, it is possible to bond three silicon wafers on which the fixed pieces 1 and 3 and the movable piece 2 are formed in large numbers first and then cut them out, thereby improving the production efficiency. Further, the fixed pieces 1 and 3 are fixed to the fixed electrodes 10 and 3 made of a high-concentration doping layer in the wafer.
0 may be formed, or an electrostatic drive circuit IC composed of a transistor, a diode, a resistance element, a capacitor, or the like may be formed. When the drive circuit is integrally formed, it is not necessary to provide the drive circuit outside.

When the electrostatically actuated relay according to the present invention is operated, a voltage of several tens of volts is required as the applied voltage, but if a booster circuit is formed on the fixed pieces 1 and 3, the input operates at several volts. . Further, the surface of the upper fixed piece 1 facing the movable electrode 21 of the electret 11 is positively polarized, and the surface of the lower fixed piece 3 facing the movable electrode 21 of the electret 31 is negatively polarized. . Of course, instead of the permanent polarization, charges of opposite polarities may be permanently given. FIG. 6 shows the relationship between the inter-electrode distance, the electrostatic force (torque applied to the movable electrode 21) and the spring load when the absolute values of the charge amounts of both 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 21, and d is a negative voltage to the movable electrode 21. The electrostatic force when applied is shown.

Next, the operation of this embodiment will be described. First, when the potentials of the fixed electrodes 10 and 30 and the movable electrode 21 are the same,
At the neutral position where the fixed electrodes 10 and 30 and the movable electrode 21 are parallel to each other, the electrostatic forces generated by the two electrets 11 and 31 have the same magnitude, and the torque acting on the movable electrode 21 is zero. The movable electrode 21 is the upper electret 31.
When tilted to the side, since the electrostatic force generated by the upper electret 11 is large, a torque that tends to tilt toward the upper electret 11 side is generated in the movable electrode 21. Conversely, when the movable electrode 21 tilts toward the lower electret 31, the electrostatic force generated by the lower electret 31 is large,
A torque that tends to tilt toward the lower electret 31 is generated in the movable electrode 21.

At this time, first, the end movable electrode 21a of the movable electrode 21 tries to deform around the movable electrode supporting fixed end 25. Next, the central movable electrode 21b tries to rotate around the central movable electrode support fixed end 26. Therefore, since the central movable electrode 21b tends to move in parallel to the fixed electrode 10 or 30, the movable electrode 21 generates a large electrostatic force with respect to the fixed electrode 10 or 30. The distance between the movable electrode 21 and the fixed electrodes 10 and 30 is always constant because they approach the fixed side in parallel, and the gap between the central movable electrode 21b and the fixed electrode 10 or 30 becomes close to 0 especially when the contact portion is turned on. (it can).

When a positive voltage is applied to the movable electrode 21, a repulsive force is generated in the upper electret 11 and the movable electrode 21, and an absorbing force is generated in the lower electret 31 and the movable electrode 21, so that the lower electret is moved to the movable electrode 21. A torque that tends to incline to the 31 side is generated. In this case, both the repulsive force and the absorbing force contribute to the torque in the same direction, so that a very large contact pressure can be obtained. Conversely, when a negative voltage is applied to the movable electrode 21, an absorbing force is generated in the upper electret 11 and the movable electrode 21, and a repulsive force is generated in the lower electret 31 and the movable electrode 21, so that the movable electrode 21 moves toward the upper electret 11 side. Torque to tilt is generated.

Further, the spring force of the movable electrode 21 is 0 at the neutral position, and when the movable electrode 21 is tilted toward either of the electrets 11 or 31, a 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 21 in FIG. 6 and the movable electrode 21 is inclined to either of the electrets 11 or 31, the electrostatic force is set to be larger than the spring force. 21 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 21 from the state in which the upper electret 11 is initially tilted, the attracting force to the upper electret 11 becomes weak and the lower electret 31 is rotated and held. . Even if the voltage applied to the movable electrode 21 is set to 0 in this state, the state is maintained. Conversely, when a negative voltage is applied to the movable electrode 21, 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 11 and 31 are different. In this illustrated example, the electrification amount of the electret 11 is set to be larger. In the state where no voltage is applied to the movable electrode 21, the attraction force from the upper portion is larger,
Stable with the upper part tilted. And the movable electrode 21
When a positive voltage is applied to the movable electrode 21, the attractive force from the lower part becomes stronger, and the movable electrode 21 is stabilized by the torque that tends to incline to the lower part. Then, when the applied voltage is removed, the restoring force of the spring is superior, so return to the neutral position,
It returns to its original position again due to 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 21.

By the above, the two electrets 11 and 3 are
Both the latching operation and the single operation are enabled by changing the balance of the charge amount of 1. (Embodiment 2) In Embodiment 1, the movable electrode 21 is cantilevered, but in this embodiment, as shown in FIGS. That is, the movable electrode 21 of the movable piece 2 has two points on both ends of the outer periphery as the supporting and fixing ends 25 of the end movable electrode 21a. And two points at the center of the side in the vertical direction are etched so as to be integrally connected to the center inner edge of the end movable electrode 21a, and the internal portion becomes the center movable electrode 21b.
In 1b, both free ends are deformed around the support fixed ends 29 on both sides of the center. Therefore, the central movable electrode 21b is the fixed electrode 10,
It moves parallel to 30. The movable contacts 23 are provided at both the free ends, and the fixed contacts 10 and 30 are provided with the fixed contacts 12 and 32 so as to correspond to the movable contacts 23. Further, notches 35 are provided at the four corners of the movable piece 2 so that an electric signal can be taken out from the fixed contact 32 of the lower fixed piece 3.
Is provided.

Corresponding to the structure of the first embodiment, the parts having the same role are designated by the same reference numerals, and basically the same operation is performed, so that the description will be omitted. The operation of torque generation of this embodiment is basically the same as that of the first embodiment, but the movable electrode 21 is deformed as follows. First, the end movable electrode 21
Since a has both ends fixedly supported by the support fixed ends 25,
Trying to transform like a bow. On the other hand, the central movable electrode 21b
At the center, the support fixed ends 29 on both sides of the center are about to deform. Therefore, the central movable electrode 21b moves in parallel with the fixed electrode 10 or 30 of the fixed piece 1 or 3, and the movable electrode 21 generates a large electrostatic force with respect to the fixed electrode 10 or 30. Especially when the contact part is turned on, the central movable electrode 2
The gap between 1b and the fixed electrode 10 or 30 is close to zero.

[0026]

According to the first aspect of the present invention, the movable electrode is sandwiched between the two fixed pieces made of a silicon wafer forming the fixed electrode and the silicon wafer forming the movable electrode. 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. those
The movable electrode has a U-shaped base material for the movable piece.
To one end connected to the base material by etching
However, the inside of the etching area is opposite to the above U-shape.
Etched in a U shape in the opposite direction and surrounded by the etched area
The central movable electrode is sandwiched between the two
When the movable end electrodes are formed in the surrounding areas on both sides,
At the free end of the central part, at the fixed contact on the fixed side
Corresponding movable contacts are provided, and the movable end electrodes are supported
Rotating around the fixed end, the central movable electrode is
Located on the side opposite to the fixed end, at the base end of the central movable electrode
The central movable electrode support consists of rotating around the fixed end
Then, the electrostatic force exerted on the movable electrode by the electret,
The combined force of externally applied electrostatic forces can be used, and since the movable electrode can be moved in a state in which it is parallel to the fixed electrode, the electrostatic force is larger than usual, resulting in a large contact pressure. It has the effect of improving the contact reliability of the contacts, and also has the effect of preventing malfunctions due to vibration and shock from the outside. Furthermore, the gap between the movable electrode and the fixed electrode can be widened, resulting in contact. The gap between the contacts can be increased to increase the breakdown voltage between contacts, and the voltage applied to the electrodes can be reduced, which has the effect of lowering the breakdown voltage of the drive circuit. Since it is made of the same material, it is possible to make many pieces on one wafer at the same time, so mass productivity is good and it can be made at low cost. Moreover, the movable piece and the fixed piece to be joined are made of the same material. Thermal expansion coefficient of the same because it is,
It does not move like bimetal, is stable against temperature changes, and since the fixing piece is made of a silicon wafer, it is possible to form drive circuits such as discharge circuits and booster circuits, so there is no need to provide an external drive device. There is an effect. Especially dynamic
At the time of operation, the end of the movable electrode is fixed to the movable electrode.
By attempting to deform around the Teitan, then
The center movable electrode rotates around the center movable electrode support fixed end.
The desired action is obtained, so the central movable electrode is fixed.
Will try to move parallel to the electrode,
As a result, the movable electrode generates a large electrostatic force against the fixed electrode,
In addition, since it approaches the fixed side in parallel, between the movable electrode and the fixed electrode
The distance is always constant, and the central movable electrode when the contact turns on.
The cantilever type that the gap between the fixed electrode and the fixed electrode approaches 0.
Ray can be realized.

According to the second aspect of the invention, there is provided a series which can form a fixed electrode.
Form two fixed pieces made of conwafer and movable electrode
It consists of a silicon wafer and is sandwiched by both fixing pieces.
It was sandwiched in an itch shape and the movable electrode was movably supported.
It is composed of a movable piece and is placed on each fixed electrode of both fixed pieces.
Rectlet is formed, and the movable piece and the fixed piece are
It is provided with contacts that come in contact with and separate from each other by movement,
The movable electrode has both ends connected to the base material of the movable piece in the movable piece.
2 points are used as the support fixed ends, and the space between the above support fixed ends
The center of both sides in the direction perpendicular to the line connecting the
Make sure that the periphery is fixed so that it is connected to the surrounding area at the fixed end.
A central movable electrode is formed at the centered area
Move the end movable electrode in the area around the area where the movable electrode is formed.
Forming and deforming around the other supporting fixed end
Since movable contacts are provided at both free ends of the central part,
During operation, both ends of the end movable electrode are fixed and supported by fixed ends
And therefore the movable electrode tries to deform like a bow.
On the other hand, the center movable electrode is centered on another support fixed end on both sides of the center.
Due to the movement of both ends of the
The pole moves parallel to the fixed piece or fixed electrode, resulting in
The moving electrode generates a large electrostatic force with respect to the fixed electrode.
When the dot is turned on, the gap between the central movable electrode and the fixed electrode is
It is possible to realize a double-ended relay that is close to zero .

[Brief description of drawings]

FIG. 1 is an exploded perspective view of a first embodiment of the present invention.

FIG. 2 is a top view of the above movable piece.

FIG. 3 is a top view of the upper fixing piece of the above.

FIG. 4 is a top view of the lower fixing piece of the above.

FIG. 5 is a sectional view of the same.

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 exploded perspective view of a second embodiment of the present invention.

FIG. 9 is a top view of the movable piece of the above.

FIG. 10 is a top view of the upper fixing piece of the above.

FIG. 11 is a top view of the lower fixing piece of the above.

FIG. 12 is a sectional view of the above.

FIG. 13 is a configuration diagram of a conventional example.

FIG. 14 is a configuration diagram of another conventional example.

[Explanation of symbols]

1 Upper fixed piece 2 movable pieces 3 Lower fixing piece 10 fixed electrode 11 electrets 12 fixed contacts 21 movable electrode 21 End movable electrode 21 Central movable electrode 25 Support fixed end 26 Support fixed end 23 Moving contact 30 fixed electrode 31 electret 32 fixed contacts

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-3-112032 (JP, A) JP-A-53-126147 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H01H 59/00

Claims (2)

(57) [Claims] 1. A movable member in which two fixed pieces made of a silicon wafer on which fixed electrodes are formed and a silicon wafer formed on a movable electrode are sandwiched between the fixed pieces so that the movable electrode is movably supported. is composed of a single, the forming an electret on the fixed electrodes of the both fixing pieces, the movable piece and a fixed piece be those provided together toward and away from contact by the movement of the movable piece, the movable electrode Etches the base material of the above movable piece into a U shape
And one end connected to the base material is used as a supporting and fixed end.
Inside the area surrounded by the ching area,
Etching in a letter shape, the center surrounded by the etching site
The central movable electrode is located between the two parts
The movable end electrodes are formed at the side peripheral portions, respectively, and
Corresponds to the fixed contact on the above-mentioned fixed side on the free end of the central part
A movable contact is provided, and the end movable electrode rotates about the support fixed end,
The central movable electrode is located on the side opposite to the above-mentioned fixed support end.
The central movable electrode composed of the base end of the central movable electrode
Electrostatic drive type relay characterized by rotating around the support fixed end . 2. A silicon wafer on which a fixed electrode can be formed.
Silicon wafer that can be formed with two fixed pieces and movable electrode
It is sandwiched between both fixing pieces
The movable electrode is composed of a movable piece supported so as to be movable.
Form an electret on each fixed electrode of the above two fixed pieces.
The movable piece and the fixed piece move to each other by the movement of the movable piece.
A movable contact is provided, and the movable electrode has both ends connected to the base material of the movable piece in the movable piece.
2 points are used as the support fixed ends, and the space between the above support fixed ends
The center of both sides in the direction perpendicular to the line connecting the
Make sure that the periphery is fixed so that it is connected to the surrounding area at the fixed end.
A central movable electrode is formed at the centered area
Move the end movable electrode in the area around the area where the movable electrode is formed.
The central portion that is formed and deforms around the other support fixed end
The movable contacts are provided at the free ends of both ends of the
Electrostatic drive type relay that.