JPH06131960A - Micro-actuator, its manufacture, electric relay, and electromagnetic relay - Google Patents

Abstract

PURPOSE:To increase the driving force with low voltage, provide the stable characteristic against the change of the environmental temperature, and reduce the cost with a simple structure by providing driving force generation sections and heater members arranged at symmetrical positions on both sides of rotary shafts. CONSTITUTION:Driving force generation sections 6a, 6b, 6c, 6d are provided at symmetrical positions on both the right and left sides of rotary shafts 3a, 3b. Heater circuits 8a, 8b having heating sections 10a, 10b, 10c, 10d are provided on a silicon monocrystal substrate l, and a bimetal is constituted of the heating sections 10a, 10b, 10c, 10d and the driving force generation sections 6a, 6b, 6c, 6d. When voltage is applied to the circuits 8a, 8b, the moving sections of the driving force generation sections 6a, 6b, 6c, 6d are heated and deformed, the moment around the rotary shafts 3a, 3b is generated on a rotation section 4, and the rotation section 4 is rotated. Large driving force can be obtained with low voltage, and the structure is not made complex. A malfunction caused by the change of the environmental temperature is prevented, and reliability can be improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microactuator which is expected to be used in the field of so-called micromachines which constitute a mechanical element by utilizing a minute structure, a manufacturing method thereof, and an electric device to which the microactuator is applied. Related to relays and electromagnetic relays.

[0002]

2. Description of the Related Art Conventionally, in order to construct a mechanical element, various parts are produced by using a normal machining method such as cutting or pressing, and then these parts are assembled to form a mechanism. Was taken.

By the way, in recent years, photolithography, dry etching, and C, which have been used for manufacturing semiconductor elements.
Techniques such as VD and PVD, and so-called micromachine techniques for forming extremely small mechanical elements by forming mechanical elements having a fine structure using materials such as single crystal silicon and polysilicon have been developed.

As an example of a micromachine manufactured by applying such a technique, there is an electric relay utilizing electrostatic attraction as shown in FIG. This relay has a fixed substrate 30A having fixed electrodes 30 and electric contacts 34, 34, 35, and 35 formed on the surface thereof, and a rotary shaft 36 formed at the center in the longitudinal direction as a fulcrum for vertical rotation. The movable member 31 of the seesaw type, which is capable of The fixed electrode 30 on the facing surface of the movable member 31 ...
Electrodes 32 ... Are formed at positions corresponding to. Further, electric contacts 33, ... Are formed at positions corresponding to the electric contacts 34, 35.

In such a structure, when a voltage is applied between the fixed electrode 30 and the electrode 32 to form an electric field, the electrostatic attraction of these causes the movable portion 31 to be vertically driven with the rotating shaft 36 as a fulcrum. Accordingly, the electrical contact 33 opens and closes the electrical contacts 34 and 35. That is, this constitutes a relay.

Explaining a little now, for example, if a positive potential is applied to the fixed electrode 30 and a negative potential is applied to the electrode 32, the electrodes 32,
Since an electrostatic attractive force is generated between 30, the movable member 31 is attracted to the fixed substrate 30A by the electrostatic attractive force to perform a seesaw motion, thereby opening / closing the electrical contacts 34, 35, that is, performing a relay operation. It is a thing.

Another example is the microvalve shown in FIG. This microvalve has a structure in which a diaphragm 37 having a thinned central portion is formed by etching a single crystal of silicon, and a dissimilar metal thin film 38 is attached to the upper surface of the thinned portion of the diaphragm to form a bimetal. To take.

The metal thin film 38 is connected to an energizing means (not shown), and the diaphragm 37 is connected through the metal thin film 38.
Is heated. Here, the coefficient of thermal expansion of the metal thin film 38 is larger than the coefficient of thermal expansion of the diaphragm 37, and deformation is caused by utilizing the difference in coefficient of thermal expansion between the two, and by this deformation, a minute valve is opened and closed. .

Explaining a little more concretely, in the illustrated example,
Since the coefficient of thermal expansion of the metal thin film 38 is larger, the diaphragm 37 is deformed into a shape like a dotted line, and as a result, an upward warp occurs in the central portion of the diaphragm 37, and the liquid provided below the diaphragm 37. The inlet 39 is opened and the valve is opened. Therefore, the liquid or gas flowing from the inflow port 39 flows out from the outflow port 40.

On the other hand, when the energization of the metal thin film 38 is stopped, the diaphragm 37 returns to its original shape and the valve is closed.

In all of the above-mentioned conventional examples, a so-called microactuator is constructed in which a minute structure is driven by some force to move and the movement is utilized.

As a conventional example of a microactuator having a structure similar to that of the movable part shown in FIG. 7, there is one previously proposed by the applicant of the present application in Japanese Patent Application No. 3-273800.

[0013]

However, since the above-mentioned conventional examples have the following problems, it is considered that there is a big problem in practical use.

First, the microactuator using the electrostatic attraction shown in FIG. 7 has a small force in principle, and thus it is difficult to obtain a large movement. Further, in order to generate the force, it is necessary to apply a high voltage to the electrodes, which requires a special power source, which causes a problem of cost increase.

On the other hand, in the microactuator shown in FIG. 8, since a simple heater heats the bimetal, it does not require a particularly high voltage, which is more advantageous than the example of FIG. Further, since the deformation stress due to the heat of the bimetal is used, there is an advantage that a large force can be generated.

However, in this microactuator, since the metal thin film 38 and the diaphragm 37 are simply joined together, even if the heater is not used for heating, the surrounding environmental temperature changes (eg, -20 to +40 degrees). ), The stress is generated only by that, the bimetal is deformed, and a malfunction occurs.

Further, in the microactuator previously proposed by the applicant of the present application, since the movable portion is driven by the magnetic attraction force, a coil is required as a driving means for generating a magnetic field outside the microactuator, and the structure is Has the drawback of being complicated. In addition, the coil has to be separately manufactured and then assembled, which complicates the assembly process and increases costs.

The present invention solves the problems of the prior art as described above, has a large driving force at a low voltage, has stable characteristics against changes in environmental temperature, and has a simple structure. An object of the present invention is to provide a microactuator that can contribute to cost reduction and a manufacturing method thereof.

Another object of the present invention is to provide an electric relay and an electromagnetic relay to which the above microactuator is applied.

[0020]

In the microactuator of the present invention, a rotary part formed on both sides of a rotary shaft and a tip part are connected to the rotary part, while a base part is rotated. A driving force generating portion which is fixed to a portion different from the portion and has a deformable movable portion between the tip end portion and the base end portion, and which is arranged at symmetrical positions on both sides of the rotation shaft. The part has a bimetal structure and is superposed on the movable part of the driving force generating part, and is provided with a heater member which heats the driving force generating part when a voltage is applied, thereby achieving the above object.

According to the structure in which the substrate is arranged so as to face the microactuator having the above structure, and the electrode pair is provided on the substrate to be electrically contacted when the rotating portion rotates, an electric relay can be realized.

Further, a substrate is disposed so as to face the microactuator having the above structure, and a magnetic layer having conductivity is formed on the rotating portion of the microactuator.
A permanent magnet is provided on the opposing surface of the substrate, and yokes having electrodes on the surfaces are provided on both sides of the permanent magnet and corresponding to the rotating portion. Rotation of the rotating portion and magnetic effect of the yoke are provided. An electromagnetic relay can be realized by a configuration in which the contact between one electrode and the magnetic layer and the contact between the other electrode and the magnetic layer are selectively performed by the cooperation of the attraction force.

Further, in the method for manufacturing a microactuator of the present invention, the rotating part formed on both sides of the rotating shaft and the tip part are connected to the rotating part, while the base end part is the rotating part. And a driving force generating portion disposed at symmetrical positions on both sides of the rotating shaft, which has a movable portion that is fixed between the distal end portion and the base end portion and is deformable. In a method of manufacturing a microactuator having a bimetal structure and a heater member that is superposed on the movable portion of the driving force generating portion and heats the driving force generating portion when a voltage is applied, at least the back surface side of the substrate. A step of forming an oxide film on the substrate, a step of forming a metal film on the front surface side of the substrate, then a step of forming the heater member by patterning the metal film by photolithography and etching, and , Photolithography Forming a slit in the thin portion of the substrate by performing photolithography and etching or other processing method on the front surface side of the substrate by a process of removing the peripheral portion of the substrate by fi This includes the step of producing the rotating shaft, the rotating portion, and the driving force generating portion, thereby achieving the above object.

[0024]

In the above structure, when a voltage is applied to the heater member, the movable portion of the driving force generating portion is heated and the movable portion is deformed due to the bimetal structure. Here, a base end portion of the movable portion is fixed, and a tip end portion of the movable portion is connected to a rotating portion arranged at both sides of the rotating shaft. Therefore, when the movable part is deformed, a moment around the rotation axis is generated in the rotating part, which causes the rotating part to rotate.

The microactuator having a structure in which the bimetal is heated to obtain a driving force as described above has an advantage that a large driving force can be obtained at a low voltage for the above reason. Moreover, the structure does not become complicated.

In addition, according to the structure in which the driving force generating portions are arranged at symmetrical positions on both sides of the rotation shaft, even if the bimetal is deformed due to a change in environmental temperature, the bimetals on both sides can be deformed. The rotational moments generated in the rotating parts are canceled by each other and become zero. Therefore, the rotating part does not rotate unexpectedly. That is, there is no risk of malfunction due to changes in environmental temperature.

Strictly speaking, of course, if the thermal expansion coefficients of the bimetals on both sides are different, the forces generated on the two will be different due to temperature changes, and there is a possibility that they will rotate. However, since the bimetals are usually formed at the same time in a batch, variations in characteristics are small and such a problem does not occur.

[0028]

EXAMPLES Examples of the present invention will be described below.

(Structure of the Microactuator of the Present Invention)
1 to 3 show a microactuator of the present invention. This microactuator A is composed of a silicon single crystal substrate 1
The back side of the is thinned while leaving the peripheral portion, and a large number of slits 2a, 2b, 2c, 2d, 5 are formed in the thinned portion.
a and 5b are formed, whereby the rotating shafts 3a and 3b, the rotating portion 4 and the driving force generating portions 6a, 6b, 6c and 6d are formed to remain, and the heater circuits 8a and 8b are provided thereon. . The portions exposed above the heater circuits 8a and 8b of the silicon single crystal substrate 1 are shown by hatching.

Driving force generator 6 of heater circuits 8a and 8b
The portions located above a, 6b, 6c, and 6d are heating units 1
0a, 10b, 10c, 10d, and the driving force generators 6a, 6b, 6c, 6d and the heating units 10a, 10b,
A bimetal is composed of 10c and 10d. Also,
A metal thin film 11 is provided on the rotating portion 4 having a rectangular shape that is long in the left-right direction. The metal thin film 11 is formed, for example, when the microactuator of the present invention is applied as an electric relay described later. The structure of each part will be specifically described below.

The portion of the silicon single crystal substrate 1 excluding the peripheral portion is thinned, and four slits 2a, 2b, 2c, 2d having an L-shape and two slits having a U-shape are formed in the thin-walled portion. 5a and 5b are provided. Due to these slits 2a, 2b, 2c, 2d, 5a, 5b, the rotating portion 4 having the above-described shape is formed in the central portion of the silicon single crystal substrate 1.

At the center of the rotating portion 4 in the width direction (left-right direction),
One ends of the rotating shafts 3a and 3b having a triangular cross section are connected in series. The other ends of the rotating shafts 3a and 3b are connected to the peripheral portion. The slits 2 are provided on the left and right sides of the rotary shafts 3a and 3b.
a, 2b, 2c, 2d are partially present, and the slit 2
The rotating shafts 3a, 3b are formed by a, 2b, 2c, 2d so as to be narrower than the peripheral portion.

The slits 2a, 2b, 2c, 2d,
The specific formation positions of 5a and 5b are as follows. Rotating part 4
Slits 2a and 2b are formed on the left and right sides of the rear side,
Slits 2c and 2d are formed on the left and right sides of the front side of the rotating portion 4. In addition, slits 5 are provided on both left and right sides of the rotating unit 4.
a and 5b are formed.

In the portions removed by the slits 2a and 5a,
The driving force generating portion 6a having a rectangular shape which is long in the left-right direction is formed. Similarly, the driving force generator 6 is applied to the other parts.
b, 6c, and 6d remain. The driving force generator 6a,
The respective tip portions 7a, 7b, 7c, 7d of 6b, 6c, 6d are connected to the four corners of the rotating portion 4, respectively. The base end portions 9a, 9b, 9c of the driving force generating portions 6a, 6b, 6c, 6d,
9d is in a state of being fixed to the silicon single crystal substrate 1 itself. Therefore, taking the driving force generating portion 6a as an example, the driving force generating portion 6a is supported in a cantilevered state with the base end portion 9a on the right side in the drawing as a fulcrum. Similarly, the driving force generators 6b, 6c, 6d are also supported in a cantilevered state.

Further, heater circuits 8a and 8b are laminated on the silicon single crystal substrate 1 constituting the above member. The heater circuits 8a and 8b are formed in a U shape as a whole, and are laminated on the silicon single crystal substrate 1 so as to surround the rotating portion 4. In such a shape, the heater circuits 8a and 8b are both separated into the inner and outer two regions, and the heater wire extending in the inner and outer two regions is formed in a labyrinth shape. Both ends 8c and 8d of the heater circuit 8a are separated at appropriate intervals in the front-rear center of the left end of the silicon single crystal substrate 1 in the outer region.

Similarly, both end portions 8e, 8 of the heater circuit 8b are
Also in the outer region, f is separated at the central portion in the front-rear direction at the right end portion of the silicon single crystal substrate 1. A heating voltage is applied from a power supply circuit (not shown) to both ends 8c, 8d, 8e, 8f of the heater circuits 8a, 8b.

In addition, in the portions of the heater circuits 8a and 8b which are superposed on the driving force generating portions 6a, 6b, 6c and 6d, the heating portions 10a and 10 having line widths narrower than those of the other portions.
b, 10c and 10d. Therefore, when a voltage is applied to both ends 8c, 8d, 8e, 8f of each heater circuit 8a, 8b, the electric resistances of the heating parts 10a, 10b, 10c, 10d are higher than those of the other parts, and therefore, concentratedly in this part. Fever occurs.

Here, the coefficient of thermal expansion of the heater circuits 8a and 8b is larger than that of the silicon single crystal substrate 1, and both of them constitute a bimetal. Therefore, for example, when a voltage is applied to both ends 8c and 8d of the heater circuit 8a, the heating units 10a and 10c generate heat, which heats the driving force generating units 6a and 6c. Due to the difference between the driving force generating portions 6a and 6c, the driving force generating portions 6a and 6c bend downward as shown by the broken line in FIG. 3 with the right-side base end portions 9a and 9c serving as fulcrums.

When such a bending occurs in the driving force generating portions 6a, 6c, the left side portion of the rotating portion 4 connected to the tip portions 7a, 7c of the driving force generating portions 6a, 6c is rotated about the rotating shafts 3a, 3b. A clockwise rotation moment Ma is generated, and eventually the rotating portion 4 rotates in the same direction with the rotating shafts 3a and 3b as fulcrums.

On the other hand, both ends 8b, 8d of the heater circuit 8b
When a voltage is applied to the heating parts 10b and 10d, heat is generated,
As a result, the driving force generators 6b and 6d are heated, but since the driving force generators 6b and 6d are cantilevered with the left-side base end portions 9b and 9d in the fixed state as fulcrums, In this case, due to the difference in the coefficient of thermal expansion between the two, the driving force generators 6b and 6d bend downward with the base end portions 9b and 9d as fulcrums, as shown in FIG.

When such bending occurs in the driving force generating portions 6b and 6d, a timepiece having the rotating shafts 3a and 3b as the center of rotation is provided on the left side of the rotating portion 4 which is connected to the tip portions 7b and 7d. A rotational moment Mb in the direction is generated, and eventually the rotating portion 4 rotates in the same direction with the rotating shafts 3a and 3b as fulcrums.

Here, the driving force generators 6a, 6b, 6c,
6d is a slit 2a, 2b, 2c, 2d with respect to the rotating part 4.
Must be isolated in. Because slit 2
If there is no a, 2b, 2c, or 2d and both are integrated, even if a bending force can act on the rotating portion 4 itself, this is applied to the rotating shaft 3
This is because no bending moment for rotating around a and 3b is generated. Explaining a little now, the slits 2a, 2b,
By providing 2c and 2d, the driving force generators 6a and 6
b, 6c, 6d and the rotating portion 4 are connected to each other, that is, the tip portions 7a, 7b, 7c of the driving force generating portions 6a, 6b, 6c, 6d,
Since the bending force acts on 7d intensively, the required bending moment is obtained.

Therefore, according to the microactuator of the present invention having the above-mentioned structure, there is an advantage that the rotating portion 4 as the movable portion can be driven with a large driving force. Moreover, since the heater circuits 8a and 8b are used as the driving means, there is an advantage that a large driving force can be obtained at a low voltage. Moreover, the structure does not become complicated.

Furthermore, the driving force generators 6a, 6b, 6c,
Since 6d is arranged symmetrically on both sides of the rotating shafts 3a, 3b, the heating unit 10a,
10b, 10c, 10d and driving force generators 6a, 6b, 6
Even when the bimetal composed of c and 6d is deformed, the rotating moments generated in the rotating portion 4 by the bimetals on both sides cancel each other out and become zero. Therefore, according to such a microactuator, since there is no possibility of causing a malfunction due to a change in environmental temperature, the reliability can be improved.

(Method for Manufacturing Microactuator of the Present Invention) Next, a method for manufacturing the microactuator of the present invention will be described. The microactuator of the present invention is manufactured through the steps of FIGS. This will be specifically described below.

First, as shown in FIG.
The surface of the silicon single crystal substrate 1 having the orientation 0) is oxidized to form SiO2 coatings 100a and 100b on both front and back surfaces of the silicon single crystal substrate 1.

Next, as shown in FIG. 4B, the heater circuits 8a and 8b are formed on the SiO2 film 100a on the front surface side.
And the metal film 101 for forming the heating portions 10a, 10b, 10c, and 10d is formed on the entire surface. Metal film 101
As the above, it is preferable to form Al, Ta, Mo, Cr, Ni, Hf, B or an alloy thereof in a thickness range of 0.1 to 10 μm.

Next, as shown in FIG. 4C, the metal film 1
Photoresist 102 is applied onto 01. Then, using a predetermined mask, only the required portion of the photoresist 102 is exposed and developed to develop a desired pattern, that is, the heater circuits 8a and 8b and the heating portion 10a.
Patterns corresponding to 10b, 10c and 10d are formed. Then, etching is performed using this pattern as a mask to form the heater circuits 8a and 8b and the heating units 10a and 10b.
Patterns b, 10c, and 10d are formed (see FIG. 4D). At this time, at the same time, both ends 8a, 8b, 8c, 8d
Is also formed.

For the etching, so-called wet etching using hydrofluoric acid, nitric acid, sulfuric acid or a mixture thereof can be used. In addition, a gas such as CF ₄ or SF ₆ is introduced into a vacuum container, and discharge is performed to turn the gas into plasma,
It is also possible to use so-called dry etching in which the metal film 101 is etched with this energy.

After the etching process is completed, the remaining photoresist 102 is removed. As a result, FIG.
, The heater circuits 8a and 8b and the heating unit 10
A desired metal film pattern having a, 10b, 10c and 10d is formed on the silicon single crystal substrate 1.

When it is necessary to form some pattern other than the heater circuits 8a and 8b and the heating portions 10a, 10b, 10c and 10d, it is possible to form the pattern by repeating the above-mentioned steps, and The metal thin film 11 can also be formed by the same method.

Next, as shown in FIG. 4F, a photoresist 103 is applied over the entire surface of the oxide film 100b formed on the back surface of the silicon single crystal substrate 1. Subsequently, this photoresist 103 is exposed and developed to remove most of the photoresist 103, leaving the periphery of the back surface. Then, the photoresist 10 with the peripheral portion removed
3, that is, using the resist pattern as a mask, the oxide film 100b is removed by ion sputtering (FIG. 4 (g)).
reference).

Next, the entire silicon single crystal substrate 1 is immersed in an etching solution containing KOH to etch the silicon single crystal substrate 1. According to such a process, the oxide films 100a and 100b are not attached ((1
In the silicon single crystal substrate 1 having the orientation of 10), the etching rate varies depending on the orientation of the crystal, so that only a specific surface is etched and progresses. That is, by this etching step, the silicon single crystal substrate 1 having the shape shown in FIG.

Next, as shown in FIG. 4I, a photoresist 104 is applied over the entire surface of the oxide film 100a on the surface of the silicon single crystal substrate 1. Subsequently, the patterns corresponding to the slits 2a, 2b, 2c, 2d, 5a, 5b are exposed and developed. Then, the oxide film 100a is removed by sputter etching using the resist pattern as a mask (see FIG. 4 (j)).

Subsequently, the entire silicon single crystal substrate 1 is immersed in an etching solution which also contains KOH as a component,
The silicon single crystal substrate 1 is etched. Then, etching of only the removed portion of the oxide film 100a proceeds, and the slits 2a, 2b, 2c, 2d, 5a,
5b penetrates. As a result, the rotating portion 4, the driving force generating portions 6a, 6b, 6c, 6d and the rotating shafts 3a, 3b having the above-described shapes can be obtained from the thinned portion of the silicon single crystal substrate 1.

In the above manufacturing method, the rotating portion 4 and the like are formed on the front surface side of the silicon single crystal substrate 1 by using the etching anisotropy in the silicon single crystal, but the manufacturing of the microactuator of the present invention is performed. The method is not particularly limited to this step, and a step of directly forming a thin film, a thin plate or the like by etching or pressing may be performed.

(Example in which the microactuator of the present invention is applied to an electric relay) FIG. 5 shows an electric relay to which the microactuator A of the present invention is applied. This electric relay is configured by disposing a substrate 19 made of a conductive material so as to face a microactuator A having the metal thin film 11 formed on the upper surface of the rotating portion 4. Here, the metal thin film 1
1 is a thin film having electrical conductivity, such as Au, Ni, C
A u, Al, Cr, Ag, Pd film or the like is used. In addition,
Regarding the corresponding part of the microactuator A,
The same numbers as above are attached.

At the portions corresponding to the left and right ends of the rotating portion 4 on the facing surface of the substrate 19, the electrode mounting protrusions 20a,
20b is formed, and a pair of left and right electrodes 21a, 21 is formed there.
b is attached.

In such a configuration, the heater circuit 8a
Alternatively, when a voltage is applied to both ends 8c, 8d or 8e, 8f of 8b, the rotating unit 4 rotates in the counterclockwise direction indicated by arrow B or the clockwise direction indicated by arrow C, for the reason described above. When the rotating portion 4 rotates counterclockwise as indicated by arrow B, the left end portion of the rotating portion 4 contacts the electrode 21a, and the electrode pair 21a, 2
1b is short-circuited. That is, the electrodes 21a and 21b are electrically connected. Similarly, when the rotating portion 4 rotates in the direction of arrow C, the right end of the rotating portion 4 contacts the electrode 21b, and the electrode pair 2
Conduction is established between 1a and 21b.

On the other hand, when the energization of the heater circuit 8a or 8b is stopped, the rotating portion 4 returns to its original position, and the electrode pair 21
The conduction between a and 21a is released.

Therefore, according to the above configuration, the heater circuit 8
By controlling the energization to a or 8b by a control means (not shown), the conduction state and the non-conduction state between the electrode pairs 21a and 21b can be controlled. That is, with such a configuration, an excellent electric relay having the characteristics of the microactuator described above can be realized.

(Example in which the microactuator of the present invention is applied to an electromagnetic relay) FIG. 6 shows an electromagnetic relay to which the microactuator of the present invention is applied. This electromagnetic relay includes a magnetic material layer 2 having electrical conductivity on the upper surface of the rotating portion 4.
The substrate 2 is attached to the microactuator A ′ on which the substrate 5 is formed.
3 are arranged to face each other. Here, the magnetic material layer 25
For example, a permalloy layer, a soft iron layer or the like is used. The corresponding parts of the microactuator A'are given the same numbers as above.

Yokes 27a and 27b are projectingly formed on portions of the facing surface of the substrate 23 corresponding to the left and right ends of the rotating portion 4, and a pair of left and right electrodes 26a and 26b are formed on the yokes 21a and 21b. There is. A permanent magnet 28 is embedded in the center of the opposing surface of the substrate 23 in the left-right direction, and a magnetic circuit is formed by this.

In such a structure, the heater circuit 8a
Alternatively, when a voltage is applied to both ends 8c, 8d or 8e, 8f of 8b to rotate the rotating portion 4 counterclockwise as indicated by arrow B or clockwise as indicated by arrow C, the yoke 27a or the yoke 2 is formed.
A magnetic attraction force is generated by 7b, the left end portion or the right end portion of the magnetic material layer 25 is attracted, and one is held in a state of being attracted. That is, the left end portion or the right end portion of the magnetic material layer 25 is connected to the electrode pair 26a or 26b, and the electrode pair 26a, 26
The conduction between b is achieved.

Even if the power supply to the heater circuit 8a or 8b is stopped from this state, the state in which the rotating portion 4 is held by one of the yokes 27a and 27b is maintained by the action of the magnetic circuit. Therefore, the electrodes 26a and 26b are still electrically connected.

In order to release this conduction state, the heater circuit 8b or 8 on the opposite side of the microactuator A'is provided.
It suffices to energize a and apply a rotational moment on the side opposite to the above to the rotating portion 4. That is, in this case, either the left or right end of the rotating portion 4 is separated from the yoke 27a or 27b against the magnetic attraction force of the yoke 27a or 27b, so that the conduction state between the electrodes 26a and 26b is released. To be done.

Here, when the rotating portion 4 rotates to a certain extent from the above state, this time the yoke 27b or 2 on the opposite side is rotated.
Since a magnetic attraction force is generated by 7a, the rotating portion 4 is held in a state of being attracted to the opposite side. Therefore, according to such a configuration, it is possible to obtain an electromagnetic relay capable of controlling the conduction state and the non-conduction state between the electrode pairs 26a and 26b by energizing the heater circuit 8a or 8b. This electromagnetic relay can also enjoy the characteristics of the microactuator of the present invention.

In addition, in the case of this electromagnetic relay, energization to the heater circuit 8a or 8b is required only at the moment when the conduction state is switched, so that there is an advantage that power consumption can be small.

Needless to say, application examples of the microactuator of the present invention are not limited to the relays of the above embodiments.

[0070]

According to the microactuator of the first aspect, since the heater circuit heats the driving force generating section that forms the bimetal with the heating section of the heater circuit, the rotating section is rotated. There is an advantage that a microactuator that can obtain a large driving force at a low voltage can be realized. Moreover, the structure does not become complicated.

In addition, since the driving force generating portions are arranged symmetrically on both sides of the rotating shaft, the bimetals on both sides are deformed even if the bimetals are deformed due to a change in environmental temperature. As a result, the rotational moments generated in the rotating parts cancel each other out. Therefore, there is no possibility of causing a malfunction due to a change in environmental temperature.
Therefore, there is an advantage that a highly reliable microactuator can be realized.

Particularly, according to the electric relay described in claim 2, there is an advantage that an excellent electric relay which can enjoy the characteristics of the microactuator described in claim 1 can be realized.

Further, in particular, according to the electromagnetic relay described in claim 3, not only can an excellent relay that can enjoy the characteristics of the microactuator described in claim 1 be realized, but also an advantage that a relay that consumes less power can be realized. is there.

Further, in particular, the method of manufacturing a microactuator according to claim 4 has an advantage that a microactuator having excellent characteristics can be manufactured.

[Brief description of drawings]

FIG. 1 is a plan view showing a microactuator of the present invention.

FIG. 2 is a sectional view taken along line X-X ′ of FIG.

FIG. 3 is a cross-sectional view taken along line Y-Y ′ of FIG.

FIG. 4 is a process drawing showing the manufacturing method of the microactuator of the present invention.

FIG. 5 is a sectional view showing an electric relay to which the microactuator of the present invention is applied.

FIG. 6 is a sectional view showing an electromagnetic relay to which the microactuator of the present invention is applied.

FIG. 7 is a perspective view showing a conventional microactuator applied to an electric relay.

FIG. 8 is a cross-sectional view showing a conventional microactuator applied to a microvalve.

[Explanation of symbols]

 1 Silicon Single Crystal Substrate 2a, 2b, 2c, 2d Slit 3a, 3b Rotating Shaft 4 Rotating Part 5a, 5b Slit 6a, 6b, 6c, 6d Driving Force Generating Part 8a, 8b Heater Circuit 10a, 10b, 10c, 10d Heating Part 11 Metal Thin Film 19 Substrate 21a, 21b Electrode 23 Substrate 25 Magnetic Material Layer 26a, 26b Electrode 27a, 27b Yoke 28 Permanent Magnet A, A'Micro Actuator

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yorisei Ishii 22-22 Nagaike-cho, Abeno-ku, Osaka-shi, Osaka Within Sharp Corporation (72) Kenji Ota 22-22 Nagaike-cho, Abeno-ku, Osaka, Osaka Within the corporation

Claims (4)

[Claims] 1. A rotary part formed on both sides of a rotary shaft as a center, and a tip part connected to the rotary part, while a base end part is fixed to a part different from the rotary part. And a base end portion having a deformable movable portion, the driving force generating portions being arranged at symmetrical positions on both sides of the rotation shaft, and a part of the driving force generating portion having a bimetal structure. A microactuator comprising: a heater member that is superposed on the movable portion and that heats the driving force generation portion when a voltage is applied. 2. An electric relay having a substrate arranged to face the microactuator according to claim 1, and an electrode pair provided on the substrate to be electrically contacted when the rotating portion rotates. 3. A micro-actuator according to claim 1, wherein the micro-actuator has a substrate disposed opposite to the micro-actuator, a magnetic layer having conductivity is formed on the rotating portion of the micro-actuator, and a permanent magnet is provided on an opposing surface of the substrate. And a yoke having an electrode on the surface is provided on both sides of the permanent magnet and corresponding to the rotating portion, and one side is provided by the cooperation of the rotation of the rotating portion and the magnetic attractive force of the yoke. An electromagnetic relay for selectively contacting the other electrode with the magnetic layer and the other electrode with the magnetic layer. 4. A rotary part formed on both sides of a rotary shaft as a center and a tip part are connected to the rotary part, while a base end part is fixed to a part different from the rotary part, and the tip part is fixed. And a base end portion having a deformable movable portion, the driving force generating portions being arranged at symmetrical positions on both sides of the rotation shaft, and a part of the driving force generating portion having a bimetal structure. Superimposed on the movable part,
In a method of manufacturing a microactuator having a heater member that heats the driving force generating portion when a voltage is applied, a step of forming an oxide film on at least the back surface of the substrate, and forming a metal film on the front surface side of the substrate. Forming, and subsequently patterning the metal film by photolithography and etching to produce the heater member; and thinning the back surface side of the substrate by photolithography and anisotropic etching except for the peripheral portion of the substrate. And a step of performing photolithography and etching or other processing method on the front surface side of the substrate to form slits in the thin portion of the substrate, thereby forming the rotation shaft, the rotation portion, and the driving force generation portion. A method of manufacturing a microactuator, comprising: