JPS6348138B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a relay having a mechanism for opening and closing contacts using electrostatic attraction force and spring restoring force.

Generally, a mechanical relay consists of at least one pair of contacts for connecting and disconnecting a signal current, a spring or support plate for holding each contact, and a spring displacement mechanism for opening and closing the contacts. The contacts include a movable contact and a fixed contact, and in many relays, the movable contact is provided on a movable spring, and the fixed contact is provided on a fixed spring or a contact support plate.

In addition, the relay has conductors and signal current terminals connected to the movable and fixed contacts, a conductor and terminal through which a drive current flows to electrically operate the spring displacement mechanism, and a signal current flows within the relay. The circuit and the circuit through which the drive current flows are isolated and independent from each other.

The opening and closing operations of the movable contact and the fixed contact are performed by the displacement operation of the movable spring using a spring displacement mechanism and spring restoring force. The spring displacement mechanism includes an electromagnetic drive type that uses electromagnetic attraction, an electrostatic drive type that uses electrostatic attraction, and the like.

As shown in FIGS. 1 and 2, the conventional electrostatic drive type relay to which the present invention pertains has a fixed electrode plate 2 provided on a glass substrate 1, one end of which is connected to the glass substrate 1.
A thin plastic plate 3 as a spring plate fixed on the top, a movable glass plate 4 whose base end side is attached to the thin plastic plate 3, a movable electrode plate 5 provided on the movable glass plate, and a fixed electrode terminal 6 formed at the end. The fixed electrode plate connecting conductor 7 includes a fixed electrode plate connecting conductor 7, a movable electrode plate connecting conductor 9 having a movable electrode plate terminal 8 formed at the end, and a metal fixing part 10 that fixes and supports the movable electrode plate 5. By applying a voltage via the movable electrode plate connecting conductor 9, an electrostatic attraction force is exerted between the fixed and movable electrode plates 2 and 5.
One end edge of the movable glass plate 4 rotates about the metal fixing part 10, and the movable contact 11 provided on the movable glass plate 4 and the fixed contact 14 connected to the signal terminal 12 provided on the glass substrate 1 come into contact. and closes the signal line. Further, 15 is an upper glass plate which is supported by a support piece 16 and forms a lid covering the main part of the relay, and 17 is a hermetic seal portion.

The electrostatic attraction force of such a relay is determined by setting the distance between the fixed electrode plate 2 and the movable electrode plate 5 as l ₀ (m) at one end and l ₁ (m) at the other end, as shown in Fig. 3. The permittivity of the atmosphere surrounding the relay is the permittivity of vacuum ε ₀ (8.855×
10 ^-12 F/m), ^the electrostatic attraction force f
(N) is given by f=(1/2)ε ₀ SV ² (1/l ₀ l ₁ ) (1).

It is desirable for such a relay to have a large electrostatic attraction force. To increase the electrostatic attraction force, follow the steps above.
As is clear from equation (1), three methods can be considered: increasing the electrode area, decreasing the distance between the electrode plates, or increasing the voltage between the electrode plates. However, increasing the electrode area means increasing the size of the entire relay, and the mechanical precision of electrode flatness, electrode positioning, etc. must be improved, which complicates the manufacturing and assembly man-hours. Furthermore, reducing the distance between the electrode plates also requires high mechanical precision as described above, making manufacturing and assembly difficult. There is a limit to reducing the distance between the plates due to the dielectric strength between the two electrode plates. Increasing the inter-electrode voltage similarly has an upper limit to the insulation between both electrode plates, which creates a contradiction in that the electrode spacing must be increased. As described above, in the conventional structure, there was no effective means for easily increasing the electrostatic attraction force.

In view of the above points, the present invention provides an electrostatically driven relay that can increase the electrostatic attractive force between fixed and movable electrode plates without increasing the area of the electrode plates. The drawings will be explained in detail below.

An embodiment in which the present invention is applied to a relay having two make contacts is shown in FIG. 4 as a longitudinal cross-sectional view, and in FIG. 5 as a perspective view of the main parts thereof. In both figures, 21 is an insulating plate, 22 is a fixed electrode plate provided on the insulating plate to apply a driving voltage, and 23 is a ferroelectric or paraelectric thin film disposed on the fixed electrode plate. The dielectric thin film 23 may be formed by coating or spraying a dielectric material, or may be formed by pasting a dielectric thin film material with an adhesive, or by forming the dielectric thin film 23 on the fixed electrode plate 22.
It may be an oxide film formed on the surface of. 24
-1 and 24-2 are fixed contacts of two signal current paths disposed on the insulating plate 21 and having heads protruding from the surface thereof, and the mutual spacing between them is 2 as will be described later.
The distance between the two movable contacts is selected to be equal to the distance between the movable contacts. Each of the two fixed contacts 24-1 and 24-2 is connected to a conductor 25-1 disposed on the lower surface of the insulating plate 21, and the end of this conductor forms a fixed side signal terminal 25-2. Connecting conductors and terminals (not shown) of the fixed electrode plate 22 are similarly provided. 26 is a lightweight movable electrode support plate made of plastic with low specific gravity, and a movable electrode plate 27 is provided on the surface facing the fixed electrode 22, and a movable electrode plate 27 is embedded in the movable electrode support plate 26. It is supported by three parallel supporting springs 28 which also serve as conductors. Each of the support springs 28-1, 28-2, and 28-3 is fixed to a fixed part 29 made of an insulating material fixed to the edge of the insulating plate 21, and can be bent about this fixed part. There is. One of the three support springs 28-3 is connected to the movable electrode plate 27, and one end forms a movable electrode terminal 30 to which a driving voltage is applied. The other two support springs 28-1, 28-2 are movable contact plates, which also serve as signal current paths, and are parallel to each other, and their mutual spacing corresponds to the spacing between the two fixed contacts 24-1, 24-2. The movable electrode support plate 26 is arranged so as to
A movable contact 31-1 or 31-2 for connecting and disconnecting the signal current path is provided at each end extending from the base, and a signal current terminal 32-1 or 31-2 is provided at the other end fixed to the fixed portion 29, respectively. 32-2 is formed. Support springs 28-1 and 28-2 have such a movable electrode plate 27 on the upper surface and are movable contact plates.
The movable electrode support plate 26 having the movable electrode supporting plate 26 penetrated therethrough constitutes the movable armature of this embodiment.

Note that 33 is a lid that also serves as a backstop for the movable electrode support plate 26, and forms a housing in cooperation with the fixed plate 21. 34 is an insulator base.

When a DC drive voltage is applied via the support spring 28-3 connected to the connecting conductor of the fixed electrode plate 22 and the movable electrode 27 of this embodiment having such a configuration, both electrode plates 22 , 27, an electrostatic attraction force is generated between the support springs 28-1, 28-2.
and 28-3 are bent, and the fixed contact 24-1, the movable contact 31-1, and the fixed contact 24
-2 and the movable contact 31-2 are in contact with each other to close a pair of signal current paths.

FIG. 6 shows a side sectional view of another embodiment of the invention. In this embodiment, the direction in which the driving voltage application terminal and the signal current terminal are led out is different from that of the previous embodiment, and the fixed side signal terminal 25'
protrudes to the side opposite to the movable signal terminal 32', and both terminals 25' and 32' are bent downward.

In the above embodiment, the fixed contact 24 is connected to the fixed plate 2.
However, if a fixed contact serving as a break side contact is provided inside the lid body 33, and a movable contact is also provided on the back side of the conductive support spring 28, that is, on the lid body 33 side, it is possible to make and An electrostatically actuated relay having a set of break contacts can be realized.

In addition, in FIGS. 4 and 5, the dielectric thin film 23
shows a structure in which the electrodes are disposed only on the fixed electrode plate 22, but they may be disposed on the surface of the movable electrode plate 27 facing the fixed electrode plate 22, or on the opposing surfaces of both the fixed and movable electrodes. may be set.

Next, the electrostatic attractive force characteristics of the electrostatic drive relay of the present invention will be described, but here, for the sake of simplicity, a case will be described in which a dielectric thin film is disposed only on the electrode on one side of the opposing electrode plates.

As shown in the schematic side sectional view of FIG. 7, the distance between the movable and fixed electrode plates at the end of the movable electrode plate 27 that is closer to the fixed point of the support spring 28 is l ₀ ,
The distance between the two electrode plates at the end opposite to the above end of the movable electrode plate 27 is l ₁ (l ₀ , l ₁ is the dielectric thin film 23
), the thickness of the dielectric thin film 23 is L
If the dielectric constant of the dielectric thin film 23 is ε, the electrode area is S, and the voltage applied between the electrode plates is V, then the force f(N) acting between the two electrodes is f=(1/2)ε ₀ SV ² [{l ₀ + (ε ₀ /ε)L
}{l ₁ + (ε ₀ /ε)L}] ^-1 (2) It is given by: Rewriting the above equation (2) using the relative permittivity ε' (=ε/ε ₀ ), we get (1/2)ε ₀ SV ² {(l ₀ +L/ε')(
l ₁ +L/ε′)} ^-1 (3). Let f ₁ be the force acting between both electrode plates obtained from equation (3), and let f 2 be the force obtained in the case where the dielectric thin film obtained from equation (1) is not interposed, then _{f 1 /} f ₂ = ( l ₀ +L) (l ₁ +L)/(l ₀ +L/
ε′)(l ₁ +L/ε′)(4). From equation (4), it is clear that by providing the dielectric thin film 23, the electrostatic attraction force becomes larger than the conventional case where no dielectric thin film is provided.

Figure 8 shows the characteristics of the electrostatic attraction force f with respect to l 1 for the cases of L = 1 μm, _V = 100 volts, and ε' = 1, 10, and 100, assuming that S = 1 cm 3 ^and l ₀ = 0.5 μm. . As is clear from this figure, even when a paraelectric material with ε'=10 is used, an electrostatic attraction force several times greater than that when ε'=1, that is, no dielectric thin film 23 is provided, can be obtained.

As described above, according to the present invention, by providing a dielectric thin film on one or both of the opposing surfaces of the fixed electrode plate and the movable electrode plate, electrostatic attraction force can be achieved without increasing the electrode area. Can be made larger than conventional ones. Furthermore, since the dielectric thin film is interposed between the movable and fixed electrode plates, there is no risk of short circuiting even if the two electrode plates come into contact with each other.Therefore, restrictions on mechanical precision are relaxed, making manufacturing and assembly easier. This gives rise to the advantage of ease of use.

[Brief explanation of the drawing]

Figure 1 is a longitudinal cross-sectional view of a conventional electrostatic drive type relay.
FIG. 2 is a plan view of the glass substrate, FIG. 3 is an explanatory diagram of the electrode spacing of the relay, FIG. 4 is a longitudinal cross-sectional view of an embodiment of the present invention, and FIG. 5 is a perspective view of the main parts. Fig. 6 is a longitudinal cross-sectional view of another embodiment, Fig. 7 is an explanatory diagram of the relationship between electrode spacing and dielectric thin film thickness, and Fig. 8 is a diagram showing the relationship between electrode spacing and dielectric thin film thickness, and Fig. 8 shows dielectric thin film thickness and electrode spacing using relative permittivity as a parameter. FIG. 3 is a characteristic diagram showing the relationship between electrostatic attraction force and distance. 21... Fixed plate, 22... Fixed electrode plate, 23...
... Dielectric thin film, 24, 24-1, 24-2 ... Fixed contact, 25-1 ... Fixed side drive voltage terminal, 25
-2... Fixed side signal current terminal, 26... Movable electrode support plate, 27... Movable electrode plate, 28, 28-1,
28-2, 28-3... Support spring, 29... Fixed part, 30... Movable electrode drive terminal, 31-1, 31
-2...Movable contact, 32-1, 32-2...Movable side signal current terminal.

Claims (1)

[Claims] 1. A fixed electrode support plate comprising a fixed electrode plate for applying a driving voltage to the surface of an insulating plate and at least one fixed contact for a signal current, and a fixing member provided at one end edge of the fixed electrode support plate. A movable electrode support plate that applies a driving voltage to the surface of the plate facing the fixed electrode of a movable electrode support plate, which is an insulating plate supported by a conductive support spring that is supported and fixed to the fixed part and can be bent about the fixed part. A movable contact plate provided with an electrode plate, having a signal current terminal formed at one end thereof penetrating through the plate body, and at least one movable contact disposed at a position capable of contacting the fixed contact at the other end. An electrostatic drive type relay comprising: a dielectric film disposed on one or both opposing surfaces of the fixed electrode plate and the movable electrode plate. type relay.