JP4089803B2 - Electrostatic relay - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electrostatic relay using an electrostatic actuator that uses electrostatic attraction as a drive source.
[0002]
[Prior art]
Unlike conventional electromagnetic relays that use electromagnets, electrostatic relays open and close contacts using electrostatic attraction as a driving force. There is no need for a coil to generate electromagnetic force, and there are few mechanical parts, making it compact. Therefore, the use of an electrostatic actuator, which is essentially a capacitor, as a drive source has the feature of low power consumption, and research is being conducted toward practical use.
[0003]
As such an electrostatic relay, for example, as disclosed in JP-A-2-100224, single crystal Si is selectively etched to form a torsion bar elastic body and a seesaw-like structure connected thereto, and the structure There is one in which a movable electrode of an electrostatic actuator and a movable contact of a relay are formed on the body, and are arranged via a spacer on an electrically insulating substrate provided with a fixed electrode and a fixed contact at positions facing each other.
[0004]
In this electrostatic relay, when a voltage is applied between the fixed electrode and the movable electrode during operation, the seesaw-like structure on the side to which the voltage is applied rotates and the movable contact is fixed by the torsion of the elastic body of the torsion bar. It is made to contact a contact.
[0005]
[Problems to be solved by the invention]
Such conventional electrostatic relays have the following problems when opening and closing a relay contact comprising a set of a movable contact and a fixed contact.
[0006]
First, when closing the relay contact, in a conventional electrostatic relay, a voltage is applied between the movable electrode of the electrostatic actuator and the substrate-side fixed electrode arranged in the seesaw-like structure on the target contact side. With the electrostatic attraction acting between them, the torsion bar elastic body is used as a rotation fulcrum, the seesaw-like structure is moved to seesaw, and the movable contact is brought into contact with the fixed contact to close the contact.
[0007]
Thus, since the conventional electrostatic relay is formed in a seesaw-like structure in which the movable electrode operates integrally with the movable contact, the movable contact contacts the fixed contact, and the seesaw-like structure rotates. When stopped, a thick beam-like air gap is formed between the fixed electrode and the movable electrode.
[0008]
However, the electrostatic attractive force is proportional to the inverse square of the electrode spacing. Therefore, even during the suction operation, the electrostatic actuator has a small electrostatic attraction due to this large air gap. For this reason, since sufficient pressure is not applied to a contact, contact resistance cannot be made small enough and practicality falls.
[0009]
Further, when the contact resistance is high, the contact is overheated due to Joule heat when a contact current flows, and a contact welding phenomenon is likely to occur. Increasing the contact pressure by increasing the operating voltage in order to reduce the high contact resistance significantly hindered the practicality of electrostatic relays.
[0010]
Next, there is a problem when opening the relay contact.
[0011]
That is, when opening the relay contact, the movable contact and the fixed contact must be separated. In this case, the electrostatic actuator is fixed, the movable electrode is electrically short-circuited, and the electrostatic attractive force between the electrodes is made zero. . Thereby, the restoring force of the elastic body of the torsion bar that rotatably supports the seesaw-like structure works, the movable contact is lifted, and the contact with the fixed contact is cut off.
[0012]
As described above, in the conventional electrostatic relay, when the relay contact is opened, only the restoring force of the torsion bar elastic body as a torsion elastic body is the separation force, and when the contact is welded by flowing a large contact current, the contact is The force to pull apart is insufficient.
[0013]
In order to avoid such a situation, the restoring force of the torsion bar elastic body may be increased. In this case, the force required to close the relay contact also increases, so the voltage applied to the electrostatic relay is increased. In other words, the practicality of the electrostatic relay is significantly reduced.
[0014]
Therefore, as a method of increasing the force to open the relay contact, the electrostatic relay seesaw-like structure is fixed to the electrostatic actuator (hereinafter referred to as the opposite electrode) opposite to the closed contact, and the voltage between the movable electrodes. It is conceivable that an electrostatic attraction force is generated by applying a force to raise the structure side that closes the contact.
[0015]
However, since the movable electrode of the electrostatic actuator having the opposite polarity is lifted, the distance from the fixed electrode is increased.
[0016]
Since the force to rotate the seesaw-like structure is a lever force, it is the product of the distance from the rotation center axis and the attractive force at that position, but the distance between the fixed electrode and the movable electrode is further away from the rotation center axis. Since the electrostatic attractive force acting there is proportional to the inverse square of the electrode interval, the attractive force of the electrostatic actuator of the opposite polarity is remarkably reduced as a result, and cannot sufficiently contribute to the force for separating the contacts. For this reason, it was difficult to increase the separation force of the relay contact other than increasing the voltage applied to the opposite electrode.
[0017]
As described above, the conventional electrostatic relay has a high contact resistance when the contact is closed, and easily causes a contact welding phenomenon. Further, since the force for separating the contact is weak, once the contact is welded, a contact welding failure is caused as it is. For this reason, it is difficult to ensure a sufficient contact current, the reliability is low, and the practicality is poor. The only way to solve this problem is to increase the voltage for driving the electrostatic relay, and the high operating voltage significantly hinders the practicality of the electrostatic relay.
[0018]
In view of the above points, an object of the present invention is to provide a highly practical electrostatic relay with low voltage drive, low contact resistance, and high contact capacity.
[0019]
Other objects and novel features of the present invention will be clarified in embodiments described later.
[0020]
[Means for Solving the Problems]
  In order to achieve the above object, the electrostatic relay of the present invention comprises:
  A substrate,
  A torsion elastic portion in the form of a doubly supported beam held on the substrate with a gap with the substrate;
  It is supported by crossing the torsion elastic part so as to face the substrate.Extending from the torsional elastic part to both sides, forming a frame shape on each side,A movable structure rotatable by torsional elastic deformation of the torsional elastic part; and
  To be located inside each frame shape of the movable structureOn both sides of the rotation fulcrum of the movable structure,RespectivelyIt has an axis parallel to the torsion elastic part and is located at the end of the torsion elastic part side or the opposite side of the torsion elastic part inside each frame shape.Via the elastic connecting part, it can rotate independently of the movable structure part by elastic deformation of the elastic connecting part.Connected to the movable structure so thatMovable electrode part,
  A movable electrode composed of the movable electrode portion or provided on the movable electrode portion; and
  Fixed electrodes respectively disposed on the substrate so as to face the movable electrode;
  At least one of the movable structuresOn the side, the end of the movable structure portion opposite to the torsional elastic portionAt least one movable contact arranged in
  And a fixed contact disposed on the substrate so as to be opposed to the movable contact.
[0021]
In the electrostatic relay, it is preferable that the movable end portion of the movable electrode portion is disposed on the rotation fulcrum side of the movable structure portion.
[0022]
  The movable end portion of the movable electrode portion may be disposed on the movable contact side of the movable structure portion.
  It is preferable that an elastic modulus of the elastic connecting portion is smaller than an elastic modulus of the doubly-supported torsion elastic portion.
[0023]
  The movable electrode and the fixed electrodeWithA dielectric layer is preferably interposed between them.
[0024]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of an electrostatic relay according to the present invention will be described with reference to the drawings.
[0025]
FIGS. 1 to 7 show a first embodiment of an electrostatic relay according to the present invention. FIG. 1 is a plan view, and FIGS. 2 to 7 are front sectional views for explaining operations. In these drawings, the electrostatic relay includes an insulating substrate 1, an anchor structure 2 standing and fixed on the substrate 1, and a doubly supported beam held by the anchor structure 2 with a gap from the substrate 1. And a relay structure 7 that can be rotated (turned) by elastic support by the torsion elastic part 3. With this configuration, the relay structure 7 has a seesaw-like structure that is rotatably held with the torsional elastic portion 3 as a rotation fulcrum P and that extends to both sides of the rotation fulcrum P across the torsional elastic portion 3. Therefore, seesaw exercise is possible.
[0026]
The insulating substrate 1 has at least a surface subjected to insulation treatment, for example, the surface is made of SiO.₂A single crystal Si substrate provided with an insulating layer. The anchor structure 2, the torsion-elastic torsion elastic part 3, and the relay structure 7 are integrally formed of polycrystalline Si or the like.
[0027]
The relay structure 7 has a movable structure portion (main body portion of the relay structure) 10 having a required rigidity for performing seesaw motion, and a torsion elastic portion 11L in the form of a doubly supported beam as an elastic communication portion on the left side and the torsion elastic portion. A movable electrode support portion 12L (which is a movable electrode portion on which a movable electrode is provided) connected to the movable structure portion 10 through 11L is formed. A torsion elastic portion 11R and a movable electrode support portion 12R (which is a movable electrode portion provided with a movable electrode) are formed. The movable electrode support portions 12L and 12R are rotatably supported (rotated) by these doubly supported torsion elastic portions 11L and 11R. Here, the torsion elastic portions 11L and 11R in the form of doubly supported beams are formed at positions near the rotation fulcrum P of the movable structure 10, and the movable end portions of the movable electrode support portions 12L and 12R are separated from the rotation fulcrum P of the movable structure 10. It is in a remote position. In the movable electrode support portions 12L and 12R, the positions of the doubly-supported torsion elastic portions 11L and 11R are rotation fulcrums L and R, respectively. Further, the torsional elastic modulus of the torsional elastic portions 11L and 11R in the form of a cantilever is smaller than that of the torsional elastic part 3 in the form of a cantilever, that is, the movable electrode support portions 12L and 12R are more compared to the movable structure portion 10. Set it so that it can rotate with a small force.
[0028]
Movable electrodes 13L and 13R are formed on the movable electrode support portions 12L and 12R on the side facing the substrate 1, and fixed electrodes 4L and 4R are fixedly disposed on the substrate 1 at positions facing the movable electrodes. As shown in FIG. 2, insulating layers (dielectric layers) 5L and 5R are provided so as to cover the surfaces of the fixed electrodes.
[0029]
Movable contact support portions 14L and 14R are integrally formed at both ends of the movable structure portion 10 constituting the main body of the relay structure 7, and the movable contact points 15L and 14R are formed on the surfaces of the movable contact support portions 14L and 14R facing the substrate. 15R is formed and arranged, and fixed contacts 6L and 6R are fixedly arranged on the substrate 1 at positions facing the respective movable contacts.
[0030]
An electrostatic actuator that generates electrostatic attraction by a voltage applied between the fixed electrodes 4L and 4R fixed on the insulating substrate 1 and the movable electrodes 13L and 13R fixed to the movable electrode support portions 12L and 12R. The fixed electrodes 4L, 4R and the movable electrodes 13L, 13R are connected to an external power source by wiring (not shown).
[0031]
The principle of operation of the electrostatic relay shown in the first embodiment will be described. First, the operation of closing the relay contact will be described.
[0032]
FIG. 2 shows the position of each electrode and each contact in a non-operating state (state where no voltage is applied), and the fixed contacts 6L and 6R and the movable contacts 15L and 15R are open. When a voltage is applied between the fixed electrode 4R and the movable electrode 13R constituting the right electrostatic actuator, an electrostatic attractive force is generated between the two electrodes, and the movable electrode support portion 12R has a double-supported beam shape with the rotation fulcrum R as the center. 3, and the movable electrode support portion 12 </ b> R changes to the contact position with respect to the substrate 1 side as shown in FIG. 3 (change until the movable electrode 13 </ b> R hits the insulating layer 5 </ b> R covering the fixed electrode 4 </ b> R). To do.) The electrostatic attractive force acting between the fixed electrode and the movable electrode of the electrostatic actuator is inversely proportional to the square of the distance. Therefore, as is apparent from FIG. 3, a significantly large electrostatic attraction is generated between the fixed electrode 4R and the movable electrode 13R, which are narrowed in a shape having a wedge-shaped air gap, and this wedge-shaped air is generated. A large attractive force is generated to narrow the gap, and as shown in FIG. 4, the movable structure 10 itself that forms the main body of the relay structure 7 is rotated to the right with the rotation fulcrum P as the center of rotation. To close the relay contact.
[0033]
In the state where the relay contact is closed, as shown in FIG. 4, the wedge-shaped air gap between the movable electrode 13R and the fixed electrode 4R can be further narrowed, so that a strong contact pressure can be obtained.
[0034]
As described above, in the electrostatic relay according to the first embodiment of the present invention, first, the movable electrode support portion 12 </ b> R that rotates with a weak force has an electrostatic actuator electrode interval at the beginning of voltage application to the electrostatic actuator. Operates at a stage where the electrostatic attraction is small and the electrode spacing is narrowed. Due to the narrow electrode spacing, a remarkably strong force is generated between the electrostatic actuator electrodes, and with this force, the main body portion of the relay structure 7, that is, the movable structure portion 10 which is the frame-shaped portion outside the movable electrode support portion is rotated. By rotating around P, the relay contacts can be closed and a stronger pressure can be applied between the contacts.
[0035]
For this reason, when using it with the same operating voltage compared with the conventional electrostatic relay, it is possible to make contact resistance low. Furthermore, since a stronger attractive force can be obtained at the stage of closing the contact, it is possible to increase the elastic modulus of the torsional elastic portion 3 that supports the relay structure 7 and the contact sticking occurs. Can be easily peeled off.
[0036]
That is, when operating at the same voltage as compared with a conventional electrostatic relay, there is less failure of contact fixation and a larger contact current can be passed. Conversely, when the contact capacity is the same as that of a conventional electrostatic relay, it is possible to drive with a lower operating voltage.
[0037]
Next, an operation for opening the relay contact will be described.
[0038]
FIG. 5 shows a state where the electrodes of the right electrostatic actuator are short-circuited (the same potential) and the right electrostatic attractive force is zero after the relay contact ON operation of FIG. In this state, the force for peeling off the contacts 6R and 15R is only a restoring force due to the elastic modulus of the doubly supported torsion elastic body 3 that elastically supports the movable structure 10 forming the main body of the relay structure 7. .
[0039]
Here, if the fixing force between the contacts 6R and 15R is larger than the restoring force, the contact of the electrostatic relay does not open, resulting in a contact fixing failure.
[0040]
In the conventional electrostatic relay, in such a case, a method is considered in which a voltage is applied between the electrodes of the left electrostatic actuator to generate a force to peel off the right contact by causing the relay structure to perform a seesaw operation on the left side.
[0041]
However, in this case, as is clear from FIG. 5, the movable electrode 13L of the left electrostatic actuator has the movable structure 10 tilted to the right and is far away from the fixed electrode 4L as compared with the non-operating state of FIG. A sufficient electrostatic attractive force cannot be generated, and as a result, a sufficient force cannot be generated for peeling off the right contacts 6R and 15R.
[0042]
However, in the first embodiment of the present invention, if a voltage is applied between the movable electrode 13L and the fixed electrode 4L of the left electrostatic actuator in the state of FIG. 5, the rotation is performed with a weak force as shown in FIG. The movable movable electrode support portion 12L rotates around the rotation fulcrum L, and the movable electrode support portion 12L shifts to the contact position with respect to the substrate 1 side (until the movable electrode 13L hits the insulating layer 5L covering the fixed electrode 4L). To change.)
[0043]
Since the electrostatic attractive force acting between the fixed electrode and the movable electrode of the electrostatic actuator is inversely proportional to the square of the distance, there is a gap between the movable electrode 13L and the fixed electrode 4L which are narrowed in the form of a wedge-shaped air gap. A remarkably large electrostatic attractive force is generated, and a large attractive force that narrows the wedge-shaped air gap is generated.
[0044]
This large electrostatic attraction force causes the movable structure 10 that forms the main body of the relay structure 7 to rotate to the left with a strong force, and the right movable contact 15R and the fixed contact 6R that have been fixed are sufficiently connected as shown in FIG. It can be peeled off with a strong force.
[0045]
According to the first embodiment, the following effects can be obtained.
[0046]
(1) The movable electrode support portions 12L and 12R provided on both sides of the rotation fulcrum P of the movable structure portion 10 are rotatably supported by the torsion elastic portions 11L and 11R in the form of doubly supported beams as elastic connection portions. When the electrostatic actuator is operated by applying a voltage between either the left or right fixed electrode and the movable electrode to operate the left or right electrostatic actuator, the movable electrode support first moves in the direction closer to the substrate side. Since it works to reduce the distance between the fixed and movable electrodes, the relay contact can be turned on with sufficient contact pressure even with low-voltage drive.
[0047]
(2) Also, when the relay contact is turned off, even if the contact causes a welding phenomenon, if a voltage is applied to the electrostatic actuator on the side opposite to the welding side contact, compared to the conventional electrostatic relay A large peeling force can be generated, and a contact welding failure can be avoided.
[0048]
(3) Since the fixed electrodes 4L and 4R are covered with the insulating layers 5L and 5R, it is possible to reliably prevent a short circuit accident in which the fixed electrodes 4L and 4R and the movable electrodes 13L and 13R are in direct contact. Even if the insulating layers 5L and 5R are interposed between the fixed electrodes 4L and 4R and the movable electrodes 13L and 13R, the insulating layers 5L and 5R are dielectrics having a dielectric constant higher than that of air, and the insulating layers 5L and 5R. It is not necessary to consider the decrease in electrostatic attraction due to the presence of (can be ignored).
[0049]
(4) As a result, it is possible to realize a highly practical electrostatic relay with low voltage drive, low contact resistance, and high contact capacity.
[0050]
8 to 14 show a second embodiment of the electrostatic relay according to the present invention. FIG. 8 is a plan view, and FIGS. 9 to 14 are front sectional views for explaining the operation. In these figures, the relay structure 7A includes a torsional elastic portion 21L in the form of a doubly supported beam as an elastic connecting portion on the left side and a movable structure portion 10A (main body portion of the relay structure 7A) via the torsional elastic portion 21L. The movable electrode support portion 22L connected to the right and left sides of the movable structure portion 10A, which is the main body portion of the relay structure 7A, is symmetrically provided with a torsional elastic portion 21R and a movable electrode support portion 22R. Is formed. The movable electrode support portions 22L and 22R are rotatably supported by the doubly-supported torsion elastic portions 21L and 21R. However, unlike the first embodiment, the torsion elastic portions 21L and 21R in the form of doubly supported beams are formed at positions near both ends of the movable structure portion 10A, and the movable end portions of the movable electrode support portions 22L and 22R are the rotation fulcrums P. It is a side position. In the movable electrode support portions 22L and 22R, the positions of the doubly-supported torsion elastic portions 21L and 21R are rotation fulcrums L and R, respectively. In addition, the torsional elastic modulus of the torsional elastic portions 21L and 21R in the form of a cantilever is equal to or less than that of the torsional elastic part 3 in the form of a cantilever, that is, the movable electrode support portions 22L and 22R are compared with the movable structure 10A. Set it so that it can rotate with the same or less force.
[0051]
Movable electrodes 23L and 23R are respectively formed on the movable electrode support portions 22L and 22R on the side facing the substrate 1, and fixed electrodes 4L and 4R are fixedly disposed on the substrate 1 at positions facing the respective movable electrodes. The insulating layers (dielectric layers) 5L and 5R are provided so as to cover the surfaces of the fixed electrodes. Movable contacts 15L and 15R are formed and disposed on the surfaces of the movable contact support portions 14L and 14R facing the substrate at both ends of the movable structure 10A, and fixed contacts 6L and 6R are disposed on the substrate 1 at positions facing the respective movable contacts. Is fixedly arranged. Other components are the same as those in the first embodiment described above, and the same or corresponding parts are denoted by the same reference numerals and description thereof is omitted.
[0052]
The operating principle of the electrostatic relay shown in the second embodiment will be described. First, the operation of closing the relay contact will be described.
[0053]
FIG. 9 shows the positions of the electrodes and the contacts in a non-operating state (a state where no voltage is applied), and the fixed contacts 6L and 6R and the movable contacts 15L and 15R are open. When a voltage is applied between the fixed electrode 4R and the movable electrode 23R constituting the right electrostatic actuator, an electrostatic attractive force is generated between the two electrodes, and the movable electrode support portion 22R has a double-supported beam shape around the rotation fulcrum R. 10 is rotated by the torsional elasticity of the torsional elastic portion 21R, and the movable electrode supporting portion 22R is shifted to the contact position with respect to the substrate 1 side as shown in FIG. To do.) The electrostatic attractive force acting between the fixed electrode and the movable electrode of the electrostatic actuator is inversely proportional to the square of the distance. Therefore, as apparent from FIG. 10, a remarkably large electrostatic attraction force is generated between the fixed electrode 4R and the movable electrode 23R, which are narrowed in a shape having a wedge-shaped air gap, and this wedge-shaped air is generated. A large attractive force is generated to narrow the gap, and as shown in FIG. 11, the movable structure 10A itself that forms the main body of the relay structure 7A is rotated to the right with the rotation fulcrum P as the rotation center, and the movable contact 15R and the fixed contact 6R. To close the relay contact.
[0054]
In the state where the relay contact is closed, as shown in FIG. 11, the wedge-shaped air gap between the movable electrode 23R and the fixed electrode 4R can be further narrowed, so that a strong contact pressure can be obtained.
[0055]
As described above, in the electrostatic relay according to the second embodiment of the present invention, first, the movable electrode support portion 22R that rotates with a weak force has a gap between the electrostatic actuator electrodes at the beginning of voltage application to the electrostatic actuator. Operates at a stage where the electrostatic attraction is small and the electrode spacing is narrowed. Due to the narrow electrode interval, a remarkably strong force is generated between the electrostatic actuator electrodes, and the force causes the main body portion of the relay structure 7A, that is, the movable structure portion 10A, which is the frame-shaped portion outside the movable electrode support portion, to rotate. By rotating around P, the relay contacts can be closed and a stronger pressure can be applied between the contacts.
[0056]
Furthermore, when the operations of the electrostatic relay of the second embodiment of the present invention and the electrostatic relay of the first embodiment are compared, in the electrostatic relay of the second embodiment, the movable electrode support portion 22R. Since the end side of the relay structure 7A is the rotation fulcrum R, when the transition from the state of FIG. 10 to the state of FIG. 11 is made, compared with the case of the transition from the state of FIG. 3 to FIG. Then, the point to apply the force for rotating the movable structure portion 10A of the main body portion of the relay structure 7A is applied to the rotation fulcrum R of the movable electrode support portion 22R at a position away from the rotation fulcrum P of the movable structure portion 10A itself. Therefore, according to the lever principle, the movable structure 10A can be rotated with a stronger rotational force.
[0057]
For this reason, compared with the electrostatic relay of the first embodiment, when used at the same operating voltage, the doubly supported torsion elastic portion 3 that supports the movable structure portion 10A that is the main body portion of the relay structure 7A. It is possible to increase the elastic modulus of the material, and it becomes easy to peel off when contact sticking occurs.
[0058]
That is, when operating at the same voltage as compared with the conventional electrostatic relay, the contact sticking failure is less than that improved by the electrostatic relay of the first embodiment, and a larger contact current can flow. It becomes possible. Conversely, in the case of the same contact capacity as that of a conventional electrostatic relay, it is possible to drive at a lower operating voltage.
[0059]
Further, as is apparent from a comparison between FIG. 4 and FIG. 11, the wedge-shaped air gap formed between the movable electrode and the fixed electrode with the relay contact closed is compared with the first embodiment. In the case of the second embodiment, it is even smaller, and it is possible to generate a stronger electrostatic attraction, and it is possible to increase the contact pressure between the fixed contact and the movable contact and reduce the contact resistance. .
[0060]
Therefore, in the second embodiment, since the contact resistance when the contact is closed is lower, when the same contact current is passed, the Joule heat generation at the contact portion is small, and the contact welding due to the heat generation temperature rise at the contact portion is small. Occurrence can be further suppressed.
[0061]
It should be noted that the torsional elasticity of the cantilever-like torsion elastic portions 21L and 21R that rotatably couple the movable electrode support portions 22L and 22R to the movable structure portion 10A and the torsional elasticity of the doubly-supported torsion elastic portion 3 are shown. If the force required for rotational driving of the movable electrode support portions 22L and 22R and the movable structure portion 10A is made equal, the processes of FIGS. 10 and 11 occur simultaneously. In this case as well, relay contacts (fixed contacts 6L and 6R) And the movable contacts 15L and 15R) are finally equalized.
[0062]
Next, the operation for opening the contacts will be described.
[0063]
FIG. 12 shows a state where the electrodes of the right electrostatic actuator are short-circuited (same potential) and the right electrostatic attractive force is zero after the relay contact ON operation of FIG. In this state, the force that peels off the contacts 6R and 15R is only the restoring force due to the elastic modulus of the doubly supported torsion elastic body 3 that elastically supports the movable structure 10A that forms the main body of the relay structure 7A. .
[0064]
Here, if the fixing force between the contacts 6R and 15R is larger than the restoring force, the contact of the electrostatic relay does not open, resulting in a contact fixing failure.
[0065]
Also in this second embodiment, in such a case, a voltage is applied between the electrodes of the left electrostatic actuator, and the movable contact portion 10A constituting the main body portion of the relay structure 7A is operated to see the right side by moving the seesaw to the left side. Generates a peeling force.
[0066]
The operation at this time is shown in FIGS. As is clear from FIG. 12, in the electrostatic relay of the present embodiment, the movable end 22La of the movable electrode support 22L on the left side of the electrostatic relay is on the rotation fulcrum P side of the movable structure 10A. Although 10A is inclined to the right, the distance d 'between the movable end 22La and the fixed electrode 4L facing it is almost the same as the distance d in the case of FIG.
[0067]
The force for rotating the movable electrode support portion 22L is a lever force with respect to the rotation fulcrum L, and the distance d ′ between the movable end portion 22La and the fixed electrode is not significantly different from that in the stationary state FIG. 9 (that is, the maximum rotational force). The distance between the end of the movable electrode 23L near the movable end 22La and the fixed electrode is not significantly different from that in the stationary state in FIG. 9), and the movable electrode support 22L easily rotates by applying a voltage between the electrodes, The state shifts to the state of FIG. Note that the rotational force can be efficiently generated by forming the movable end 22La of the movable electrode support 22L and the end of the movable electrode 23L as close as possible.
[0068]
Therefore, as in the case of the first embodiment shown in FIGS. 5 and 6, the elastic modulus of the torsion elastic portions 21L and 21R in the form of doubly supported beams that rotatably support the movable electrode support portions 22L and 22R is weakened. Even without setting, by applying a normal operating voltage, the movable electrode support 22L can reliably rotate, and the distance between the movable electrode 23L and the fixed electrode 4L can be reduced.
[0069]
As shown in FIG. 13, a remarkably large electrostatic attractive force is generated between the movable electrode 23L and the fixed electrode 4L that are narrowed in the form of a wedge-shaped air gap, and a large force that narrows the wedge-shaped air gap is generated. appear.
[0070]
As described above, in the electrostatic relay according to the second embodiment, even if the right relay contact is fixed, if the normal operating voltage is applied between the left electrodes, the movable electrode support 22L is It rotates reliably and operates at a stage where the electrostatic actuator electrode interval is large and the electrostatic attractive force is small at the beginning of voltage application to the electrostatic actuator to narrow the electrode interval. Due to the narrow electrode interval, a remarkably strong force is generated between the electrostatic actuator electrodes, and the movable structure 10A is rotated by the force, and the right relay contact, that is, the fixed contact 6R and the movable contact 15R are opened as shown in FIG.
[0071]
Furthermore, in the electrostatic relay according to the present embodiment, the movable electrode support portion 22L rotates with the end portion side of the movable structure portion 10A forming the main body portion of the relay structure 7A serving as a fulcrum, so the process proceeds from FIG. 13 to FIG. At this point, compared with the case of shifting to FIG. 7 in the first embodiment, the movable point where the force for rotationally driving the movable structure 10A is located away from the rotation fulcrum P of the movable structure 10A. Since it is applied to the fulcrum L of the electrode support portion 22L, the movable structure portion 10A can be rotated with a stronger rotational force by the lever principle. Therefore, if the structure of the present embodiment is taken, it is possible to generate a force for tearing off the contact point fixed with a stronger force than in the first embodiment.
[0072]
As described above, the electrostatic relay according to the second embodiment of the present invention can be realized by applying a voltage to the electrostatic actuator on the side opposite to the welding side contact even if the contact causes a welding phenomenon. Compared to the electrostatic relay, it is possible to generate a larger peeling force than when the first embodiment is used, and it is possible to more reliably avoid contact welding failure. Other functions and effects are the same as those of the first embodiment described above.
[0073]
In the above-described embodiment, an example in which a pair of movable electrode support portions and movable electrodes are provided for the relay structure has been described. A pair of movable electrode portions (that is, a movable electrode support portion and a movable electrode) may be provided, and as long as they are functionally equivalent, a configuration other than a bilaterally symmetric structure may be used depending on the purpose.
[0074]
In the above embodiment, an example in which the movable electrode is formed on the substrate surface side of the relay structure has been described. However, the position of the electrode is not limited to this, and an electrostatic attractive force is substantially generated between the fixed electrode and the movable electrode. For example, if the relay structure is a high dielectric constant insulator or a high resistance body, the position of the movable electrode may be disposed on the opposite surface of the relay structure on the substrate surface side. If the relay structure is composed of a conductive member, the structure itself can be used as a movable electrode (in this case, the movable electrode support part is unnecessary and the movable electrode part itself constitutes the movable electrode). .
[0075]
In addition, regarding the arrangement of relay contacts consisting of a set of fixed and movable contacts, in the above embodiment, a relay circuit having a relay contact at both ends of the relay structure and capable of configuring a relay circuit that performs a complementary operation is shown. When a single contact is sufficient, a relay contact may be provided only on one side. Further, a plurality of contacts may be formed on the relay structure so that a plurality of circuits can be simultaneously opened and closed.
[0076]
Furthermore, in each of the embodiments, a torsion elastic portion in the form of a cantilever is used as an elastic communication portion that connects the movable structure portion, which is the main body portion of the relay structure, and the movable electrode portion. Any structure other than the torsional elastic part can be used.
[0077]
【Example】
Next, the present invention will be specifically described with reference to examples.
[0078]
15 and 16 are a plan view and a front sectional view of the electrostatic relay formed in this example, and have the same structure as that of the second embodiment. In the present embodiment, first, as shown in FIG.₂The single crystal Si plate 1 on which the insulating layer 1a is formed is used as a substrate, Au having a thickness of about 500 nm is formed on the entire surface of the substrate by sputtering, and then photoetching is used to fix the fixed electrodes 4L and 4R of the electrostatic actuator and the relays. The fixed contacts 6L and 6R were patterned. Next, an SiN insulating layer having a thickness of about 100 nm is formed on the entire surface of the substrate by reactive sputtering, and the insulating layer is selectively removed by leaving the same on the fixed electrodes 4L and 4R of the electrostatic actuator by the photoetching method. , 5R.
[0079]
Next, as shown in FIG. 17B, a low-pressure CVD method is used to form SiO that becomes the sacrificial layer 31 on the entire surface of the substrate.₂A film was deposited about 3 μm. Next, SiO at the position where the movable contacts 15L and 15R are formed.₂The film is dug down about 500 nm by the RIE method. Further, an Au film of about 500 nm is formed on the entire surface of the substrate together with a SiN reaction prevention layer of about 20 nm, and patterned into a predetermined shape by photoetching to form the movable electrodes 23L and 23R of the electrostatic actuator and the movable contacts 15L and 15R of the relay. did. Thereafter, the SiO of the sacrificial layer 31 is further reduced.₂The portion 32 corresponding to the anchor structure 2 of the film is selectively removed using photoetching.
[0080]
Finally, a low-pressure CVD method was used to form a polycrystalline Si film 33 of about 4 μm on the entire surface of the substrate as shown in FIG. 17C, and the shape of the relay structure 7A described below was patterned by the RIE method. Thereafter, SiO of the sacrificial layer 31₂The film was selectively etched with HF, and the relay structure 7A shown in FIGS. 15 and 16 was released to form.
[0081]
As shown in FIG. 15, the relay structure 7A has a cantilever-like torsion elastic portions 3a, 3b having a length a from the anchor structure 2 of about 140 μm and a width of about 6 μm, and a doubly-supported torsion elastic portion 3a. , 3b, a movable structure portion (frame portion) 10A as a main body portion of the relay structure 7A projecting so that the length b on one side is about 220 μm, and the left and right sides of the torsion elastic portions 3a, 3b in the form of doubly supported beams. The torsional elastic portions 21La, 21Lb and 21Ra, 21Rb having a length c of about 80 μm and a width of about 3 μm formed at a protruding position of 200 μm, a length d connected to the elastic portion of about 150 μm, a width e is composed of electrostatic actuator movable electrode support portions 22L and 22R having a length of about 200 μm, and movable contact support portions 14L and 14R having a length of about 50 μm. The movable electrode support portions 22L and 22R are rotated by the torsional elasticity of the cantilevered torsion elastic portions 21La, 21Lb and 21Ra and 21Rb, respectively, while rotating freely by the torsional elasticity of the cantilevered elastic portions 3a and 3b. It has a possible structure.
[0082]
This electrostatic relay closes the relay contact by applying an operating voltage of about 20V between the left and right electrostatic actuators. At this time, the contact resistance is about 0.2Ω and the contact current flows at 100 mA. No contact welding occurred. Further, when a contact current of 200 mA was applied, a contact welding phenomenon was observed, but it could be easily restored by applying an operating voltage to the electrostatic actuator on the side opposite to the welding side relay contact.
[0083]
As described above, the electrostatic relay of this embodiment has sufficiently practical characteristics as a small signal relay, for example, SiO which becomes the sacrificial layer 31 in the manufacturing process of FIG.₂It is also possible to operate at a lower voltage by changing the shape dimension such as reducing the film thickness or increasing the electrostatic actuator electrode area.
[0084]
As a comparative example, a conventional structure having the same basic structure and dimensions, having no movable movable electrode support portion and having a movable electrode fixed to the main body of the relay structure was created and evaluated. However, the contact resistance showed a high value of 5 to 10Ω or more, and an operating voltage of 40V or more was required to reduce the contact resistance to 1Ω or less. Further, when a contact current of several mA was applied, the contacts were welded, and the off operation became impossible. At this time, even when an operating voltage of 20 V was applied to the electrostatic actuator on the side opposite to the welding contact, the contact could not be opened.
[0085]
As is clear from the above, if the electrostatic relay structure of the present invention is used, it has been impossible to achieve in the past with low voltage drive, low contact resistance, high contact capacity, extremely high reliability, high practical electrostatic capacity. The relay can be easily configured.
[0086]
In this embodiment, the example in which the relay structure is formed by using the thin film forming technique is shown. However, the configuration method of the electrostatic relay of the present invention is not limited to this, and for example, a single crystal Si as a relay structure. After the movable contact and the movable electrode are formed on the substrate, it is formed into a predetermined structure by using a technique such as anisotropic etching, and then pasted on the insulating substrate on which the fixed contact and the fixed electrode are similarly formed via a spacer. .
[0087]
Even in such a case, it is possible to easily obtain an electrostatic relay having a large contact capacity, low voltage drive, and extremely high reliability as compared with the conventional structure.
[0088]
Moreover, it is also possible to use the metal thin plate which carried out the insulation process on the surface as a relay structure. The electrostatic relay formed by such a method can be applied to an application in which a larger contact current flows than an electrostatic relay using a thin film formation technique.
[0089]
Although the embodiments and examples of the present invention have been described above, it is obvious to those skilled in the art that the present invention is not limited thereto and various modifications and changes can be made within the scope of the claims. I will.
[0090]
【The invention's effect】
As described above, according to the present invention, the conventional electrostatic relay has a problem in that it is weak against contact electrode welding, it is difficult to ensure a sufficient contact current, and the reliability is low and the practicality is low. It is possible to realize a highly reliable electrostatic relay with low contact resistance, large contact current capacity, low operating voltage, and few contact welding failures.
[0091]
Due to the remarkable improvement of these relay characteristics, the electrostatic relay of the present invention can constitute a highly practical relay as compared with the conventional electrostatic relay.
[Brief description of the drawings]
FIG. 1 is a plan view showing a first embodiment of an electrostatic relay according to the present invention.
2 is a front sectional view taken along the line II-II in FIG.
FIG. 3 is a front sectional view showing a state in the middle of a contact-on operation in the first embodiment.
FIG. 4 is a front sectional view showing a contact-on operation completion state in the first embodiment.
FIG. 5 is a front sectional view showing a state in which the applied voltage of the electrostatic actuator is set to zero after the contact-on operation in the first embodiment.
FIG. 6 is a front sectional view showing a state in the middle of the contact-off operation in the first embodiment.
FIG. 7 is a front sectional view showing a contact-off operation completion state in the first embodiment.
FIG. 8 is a plan view showing a second embodiment of the electrostatic relay according to the present invention.
9 is a front sectional view taken along the line IX-IX in FIG.
FIG. 10 is a front sectional view showing a state in the middle of a contact-on operation in the second embodiment.
FIG. 11 is a front sectional view showing a contact-on operation completion state in the second embodiment.
FIG. 12 is a front sectional view showing a state in which the applied voltage of the electrostatic actuator is zero after the contact-on operation in the second embodiment.
FIG. 13 is a front sectional view showing a state in the middle of contact-off operation in the second embodiment.
FIG. 14 is a front sectional view showing a contact-off operation completion state in the second embodiment.
FIG. 15 is a plan view showing an embodiment of the present invention.
16 is a front sectional view taken along the line XVI-XVI of FIG.
FIG. 17 is an explanatory diagram showing a manufacturing process of the electrostatic relay according to the embodiment of the present invention.
[Explanation of symbols]
1 Substrate
2 Anchor structure
3, 11L, 11R, 21L, 21R A torsion elastic part of a cantilever shape
4L, 4R fixed electrode
5L, 5R insulation layer
6L, 6R fixed contact
7,7A Relay structure
10, 10A movable structure
12L, 12R, 22L, 22R Movable electrode support
13L, 13R, 23L, 23R Movable electrode
14L, 14R movable contact support
15L, 15R movable contact
31 Sacrificial layer

Claims (5)

A substrate,
A torsion elastic portion in the form of a doubly supported beam held on the substrate with a gap with the substrate;
The torsion elastic part is supported so as to face the substrate and extends from the torsion elastic part to both sides, and forms a frame shape on each side, and is rotatable by the torsion elastic deformation of the torsion elastic part. A movable structure,
On either side of the rotation fulcrum of the movable structure so as to be located within each frame shape of the movable structure, the torsional elastic portion in the interior of the frame-shape each have the torsional elastic portion parallel to the axis The movable structure portion is configured to be rotatable independently of the movable structure portion by elastic deformation of the elastic connection portion via an elastic communication portion located on an end of the side or the opposite side of the torsion elastic portion. A movable electrode connected to
A movable electrode constituted by the movable electrode portion or provided on the movable electrode portion;
Fixed electrodes respectively disposed on the substrate so as to face the movable electrode;
At least one movable contact disposed on at least one side of the movable structure portion at an end of the movable structure portion opposite to the torsional elastic portion ;
An electrostatic relay, comprising: a fixed contact disposed on the substrate so as to face the movable contact so as to come into contact therewith.   The electrostatic relay according to claim 1, wherein a movable end portion of the movable electrode portion is disposed on the rotation fulcrum side of the movable structure portion.   The electrostatic relay according to claim 1, wherein a movable end portion of the movable electrode portion is disposed on the movable contact side of the movable structure portion. 4. The electrostatic relay according to claim 1, wherein an elastic modulus of the elastic connecting portion is smaller than an elastic modulus of the torsion elastic portion of the doubly supported beam shape. The electrostatic relay according to claim 1, wherein a dielectric layer is interposed between the movable electrode and the fixed electrode.

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