JPH07192575A - Membrane switch - Google Patents

Abstract

PURPOSE:To prevent the breakage of a device main body owing to the discharge of static electricity form a switch surface, while improving the ON and OFF performance by the operation of the switch, as to the structure of a membrane switch. CONSTITUTION:A flexible upper side board 3 to form a circuit pattern, and a lower side board 5 are stacked through a spacer 4, and electrodes 7, 9a, and 9b are formed on the opposing surfaces of both boards. On the upper side board 3, a metal sheet 2 and a surface sheet 1 are composed by stacking integrally in the same manner. In the metal sheet 2, slits are provided at the positions corresponding to the electrodes respectively while connecting the parts of the slits to the metal sheet main body, and also an actuator 8 of T- shape is formed in the metal sheet 2. As a result, by the pressing of an operating part, the actuator 8 pushes down the electrode 7 of the upper side board 3 in parallel, and the switching operation can be carried out. Furthermore, the discharge of static electricity on the circuit patterns of the upper side board and the lower side board can be prevented by this metal sheet 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a membrane switch used for an input device of an apparatus, and more particularly to a membrane switch which has improved operability due to measures against static electricity on the switch and miniaturization of an operating portion.

[0002]

2. Description of the Related Art In a conventional membrane switch, a flexible upper substrate on which a circuit pattern is formed on a synthetic resin film and a lower substrate on which a circuit pattern is formed are laminated via a spacer, and the both substrates face each other. Electrodes are formed on the respective surface sides. Normally, the electrodes are separated by the action of this spacer, and when the operating portion of the surface sheet provided on the upper substrate is pressed with a finger or the like, the upper substrate is bent and both electrodes come into contact with each other and the switch is turned on. .

On the other hand, in the method in which the operability is improved, a metallic click plate which gives a click interval at the time of operation is attached on both electrodes of the upper substrate, and a surface sheet is formed thereon. Alternatively, as described in JP-A-4-28125, a surface sheet is formed in a dome shape in place of the click plate, and the click plate or the dome portion is deformed by pressing a finger or the like to form an electrode on the upper substrate. The switch came in contact with the electrode of the lower substrate pressed in.

[0004]

However, the recent device requires a large number of key switches of the input device in order to realize multi-functionalization and downsizing, and the number of circuit patterns on the upper and lower substrates is also increased. Many will be densified. It is also necessary to downsize the operation part of the key switch.

As described above, in the conventional membrane switch, in view of the reliability of the switch operation, the size of the operating portion, the electrodes, and the pitch of the switch require the size of the operating finger or a larger size, In addition, even with the type that provides a click feeling with improved operability, there was a limit to miniaturization due to restrictions on the attachment of the click plate and the dome shape, and the receding of the click feeling due to miniaturization.

Further, the high-density circuit pattern is formed near the end surface of the film. Since the membrane switch is constructed by laminating and laminating this film, there is a problem that the device body is broken by static electricity from the end face of the membrane switch.

The object of the present invention is to improve the operation when operating with a finger.
It is an object of the present invention to provide a membrane switch in which the electrodes of the lower substrate are surely brought into contact with each other in parallel with each other to improve operability and eliminate electrostatic damage.

[0008]

According to the present invention, a flexible upper substrate and a flexible lower substrate are laminated via a spacer, and electrodes formed on the opposing surfaces of both substrates are detachable. A switch, further, a T-shaped actuator is formed at a position corresponding to each electrode so as to be connected to a thin metal plate having electrical conductivity, and is provided on the upper substrate, and an operation unit is provided thereon. A membrane switch in which the surface sheets having the above are laminated is obtained.

In the present invention, the actuator is pushed down in parallel by pushing the operating portion of the topsheet, whereby the electrodes of the upper substrate come into contact with the electrodes of the lower substrate in parallel with each other, and the certainty of the switch operation is increased. Moreover, electrostatic breakdown can be prevented by applying static electricity to the thin metal plate.

[0010]

Embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is an exploded perspective view of an embodiment of the present invention, FIG. 2 is a sectional view of a switch portion of this embodiment, and FIG. 3 is a sectional view showing the operation of the switch.

On the flexible lower substrate 5 made of synthetic resin, two electrodes 9a and 9b are printed and formed together with the circuit pattern 10 per switch. This lower substrate 5
A reinforcing plate 6 is provided on the back side of the plate to receive the pressure when the switch is operated. Similarly, on the flexible upper substrate 3 made of synthetic resin, an electrode 7 having a size substantially equal to the two electrodes 9a and 9b is printed and formed on the surface facing the electrodes 9a and 9b together with the circuit pattern 11. A spacer 4 having a hole 12 having a size larger than the area is provided between the upper substrate 3 and the lower substrate 5.

A metal thin plate 2 (copper, aluminum stainless steel, etc.) having electrical continuity is provided on the upper substrate 3, and a T-shaped actuator 8 is provided at a position corresponding to the electrode 7 through a slit. Is formed so as to be continuous with the main body of the metal thin plate. Further, the surface sheet 1 on which the operation portion 13 of the switch is displayed is provided thereon, and the operation portion 3,
The positions of the actuator 8, the electrode 7, the hole 12, and the electrodes 9a and 9b are matched, and all of them are bonded and laminated.

In the membrane switch of this embodiment manufactured as described above, when the operating portion 13 is pushed by a human finger or the like,
As shown in FIG. 3, the actuator 8 is pushed down in parallel to bend the electrodes and penetrate the hole 12 to form the two electrodes 9a and 9b.
Touch and switch on. Then, when the finger is released, the upper substrate 3 and the surface sheet 1 return to their original shapes due to the elasticity, and the switch is turned off. Further, the thin metal plate 2 is provided on the upper substrate 3, and the outer shape is also the size of the upper substrate 3 and the lower substrate 5, and the projecting portion 14 is provided on a part thereof to be connected to the casing earth of the apparatus main body. It is made possible to discharge the static electricity received during operation to the body ground.

In the above embodiment, the actuator 8 is formed on the flat metal thin plate 2. However, in another embodiment, by providing the convex portion 15 (broken line portion in FIG. 1) on the actuator 8 portion, It is also possible to apply pressure so as to concentrate on the electrode 7 to further ensure contact with the electrodes 9a and 9b.

[0016]

As described above, according to the present invention, the thin metal plate is provided between the upper substrate and the surface sheet, and the thin metal plate is provided with the T-shaped actuator groove corresponding to the electrode portion of the upper substrate. As a result, even if the operating portion formed on the surface sheet is made smaller and the pitch is made narrower, the actuator is pushed down in parallel regardless of the size or the position of the finger or the like that presses the operating portion, and the electrodes on the upper substrate are moved downward. It is possible to make reliable contact with the electrodes.

Further, since a thin metal plate having a size matching the outer shape of the membrane switch is provided under the surface sheet, static electricity received during operation flows to the metal film, and the circuit to the upper and lower substrates located under the metal film. There is an effect that it is possible to eliminate the influence of static electricity on the apparatus main body without flowing to the pattern.

[Brief description of drawings]

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

FIG. 2 is a sectional view of a switch portion of the embodiment shown in FIG.

FIG. 3 is a sectional view of the switch portion shown in FIG. 2 during operation.

[Explanation of symbols]

 1 Surface Sheet 2 Metallic Film 3 Upper Substrate 4 Spacer 5 Lower Substrate 7 Electrode 8 Actuator 9a, 9b Electrode 12 Hole 13 Operation Part

Claims (3)

[Claims] 1. A membrane switch in which a flexible upper substrate and a flexible lower substrate are laminated via a spacer, and electrodes formed on the opposing surfaces of both substrates are freely contactable and separable, and a metal having electrical conductivity is provided. A T-shaped actuator is formed so as to be continuous with the thin plate at a position corresponding to each electrode and is provided on the flexible upper substrate, and a surface sheet having an operation portion for contacting and separating the electrode via the actuator is provided on the metal thin plate. Membrane switch characterized by being laminated on. 2. The membrane switch according to claim 1, wherein a convex portion is formed on a portion of the actuator facing the electrode on the flexible upper substrate. 3. The membrane switch according to claim 1, wherein the thin metal plate is grounded.