JPH03176921A - Membrane switch - Google Patents

Abstract

PURPOSE:To prevent the defective action due to the change of the ambient temperature by providing a groove connecting exposed sections of a spacer to the outside on one of a spacer layer on the first substrate and a spacer layer on the second substrate. CONSTITUTION:When the first substrate 11 is overlapped on the second substrate 12, a groove 33 formed on a spacer layer 3 on the substrate 11 is faced to a groove 33 formed on a spacer layer 3 on the substrate 2, and a passage is formed by both of them. This passage is communicated to a space formed by exposed sections 31, 31, and its one end is communicated to the outside air by the portion of a terminal section 141. Even if the ambient temperature is changed, the inside space is kept at the atmospheric pressure, and the hindrance of the on/off action due to the change of the ambient temperature can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a membrane switch that turns on and off between patterns formed on two substrates.

[Conventional technology]

Conventional membrane switches using flexible substrates are
It is used in parts such as operating switches of electronic equipment.

FIG. 6 is a side sectional view showing the structure of such a membrane switch 80.

As shown in the figure, this membrane switch 8° is inserted between a first case 800 made of resin and a second case 810 made of resin.

Here, the membrane switch 80 is constructed by inserting a spacer 83 made of a flexible substrate between a first substrate 81 and a second substrate 82 made of a flexible substrate. Here, each of the first substrate 81 and the second substrate 82 has
Contact patterns 811 and 821 are formed facing each other. Further, a six 831 is provided at a position where the contact patterns 811 and 821 of the spacer 83 face each other. Further, a click spring 84 is attached to the top of the contact pattern 811, and a push button portion 81°a integral with the second case 810 is disposed above the click spring 84.

When the push button portion 810a is pressed, the push button 84 is reversed, and the contact button 811 comes into contact with the contact pattern 821, making the two electrically conductive.

However, in this type of membrane switch,
Since it is necessary to insert and fix the spacer 83 between the first board 81 and the second board 82, it is necessary to install the spacer 83 with a scale that takes time and effort, or the fixing position of the spacer 83 is shifted, resulting in defective products. There was a fear that it would happen.

Therefore, the applicant of this application filed an earlier patent application (Japanese Patent Application No. 126743).
In No. 3), we proposed a membrane switch that does not require the spacer 83 and has a simple structure.

FIG. 7 is a side sectional view of this membrane switch without showing the main parts.

As shown in the figure, this membrane switch 9° includes a first substrate 91 made of a flexible sheet and a second substrate 93 made of a flexible sheet, and a contact point is provided on each of the two substrates 91 and 93. Circuit pattern with pattern 94°95 (
(not shown), and further, a thermoplastic resin is applied to the entire surface of both substrates except for the exposed portions 96a and 97a around the contact patterns 94 and 95, thereby forming a spacer layer 96.9.
7 was formed, and the contact surfaces of the spacer layers 96 and 97 (7) were further thermally welded.

When the push button 98 is pressed in the direction of the arrow, the contact pattern 94 comes into contact with the contact pattern 95, and the circuit patterns on both substrates 91 and 93 are electrically connected.

With this configuration, the spacer 8 as shown in FIG.
3 is no longer necessary, and since the spacer layers 96 and 97 firmly fix the space between the two thread plates 91 and 93, the contact patterns 94 and 95 will not shift.

Further, as in this embodiment, by forming the spacer layers 96 and 97 on all parts other than the exposed parts 96a and 97a, the space formed by the exposed parts 96a and 97a is sealed, resulting in a waterproof structure.

[Problem to be solved by the invention]

However, in this membrane switch 90,
Since the space formed by the exposed parts 96a and 97a is sealed, when heat is applied to this part, the air in the sealed space expands, the air pressure in this part increases, and the push button 9
There was a problem in that even if 8 was pressed in the direction of the arrow, the contact pattern 94 could not be pressed down. Conversely, when this part cools down, the air in the sealed space contracts, the air pressure in the space drops, and there is a risk that the contact patterns 94 and 95 will turn on even if the push button 98 is not pressed. There was also a problem.

The present invention has been made in view of the above points, and provides a membrane switch with a simple structure that does not inhibit the on/off operation of the contact pattern of the membrane switch even if the ambient temperature changes.

[Means for Solving the Problems] In order to solve the above problems, the present invention comprises a first substrate made of a flexible sheet and a second substrate made of a flexible sheet or a hard plate, A circuit pattern having a contact pattern is formed on each of the substrates, and a spacer layer is formed by applying a thermoplastic resin to a predetermined portion of the side substrate excluding at least the exposed portion around the contact pattern. A membrane switch in which side substrates are stacked so as to face each other, spacer layers of the side substrates are brought into contact with each other, and the contact surfaces are thermally welded, the spacer layer on the first substrate or the spacer layer on the second substrate being A groove is formed in at least one of the spacer layers to connect the exposed portion of the spacer layer to the outside of the spacer layer.

Further, the present invention includes a first substrate made of a flexible sheet and a second substrate made of a metal plate, and a circuit pattern having a contact pattern is formed on the first substrate, and at least a periphery of the contact pattern is provided. A spacer layer is formed by applying a thermoplastic resin to a predetermined portion excluding exposed portions of the second
A thermoplastic resin is applied to the upper surface of the substrate to form an insulating layer, and a circuit pattern having a contact pattern is formed on the insulating layer, and the side substrates are stacked so that the contact backs of the side substrates face each other. In addition, the membrane switch is a membrane switch in which the contact surfaces of a spacer layer of a first substrate and an insulating layer of a second substrate are thermally welded, the spacer layer having at least one of the spacer layer and the insulating layer. A groove was provided to connect the exposed part to the outside air.

[Effect]

As mentioned above, since the spacer layer or insulating layer of the membrane switch is provided with a groove connected to the outside air, the space formed by the exposed part of the spacer layer inside the membrane switch is opened to the outside air by the groove, and this space is always at atmospheric pressure. It will be kept as follows.

〔Example〕

Hereinafter, one embodiment of the membrane switch according to the present invention will be described in detail based on the drawings.

FIGS. 1(a), (b), and (c) are plan views showing the procedure for creating this membrane switch.

First, as shown in FIG. 3A, a flexible Bossester film (a 100 μm thick film was used in this embodiment) is formed into a substantially rectangular shape to form a flexible substrate 1. At this time, a slit 13 is provided in the center of the flexible substrate 1 to divide the flexible substrate 1 into a first substrate 11 and a second substrate 12. Further, each of the first substrate 11 and the second substrate 12 is provided with a strip-shaped lead-out portion 14,15.

On the other hand, a circuit button 16 is screen printed on the flexible substrate 1 using silver carbon. Note that a plurality of small circular contact patterns 17 are formed at predetermined locations in this circuit pattern 16. Also, circuit pattern 1
6 is also printed on the drawer section 14.

Next, as shown in FIG. 2B, a vinyl chloride paint (in this example, "Spacer Resist XB- 803) is screen printed to form the spacer layer 3.However, the contact pattern 17 portion is not coated with paint, and the circular exposed portion 31 is formed.The tip portion of the drawer portion 14 is also coated with paint. terminal part 14 without applying
1 was constructed. A groove 33, which is not coated with paint, is formed to connect the exposed parts 31 and extend the end thereof to the terminal part 141 of the pull-out part 14. Note that the exposed portion 31 and the groove 33 are formed symmetrically on the first substrate 11 and the second substrate 12.

Note that the spacer layer 3 in this example was made to have a thickness of approximately 50 μm by applying the paint twice.

Next, the first substrate 11 side is bent around the slit 13, and the spacer layer 3 on the first substrate 11 is stacked on the spacer layer 3 on the second substrate 12, as shown in FIG. match.

Next, both the spacer layers 3 of the first substrate 11 and the second substrate 12 are
, 3 are pasted together, and the state when they are pasted together is shown in FIG.

FIG. 2 is a side sectional view of the main part (cut along line A-A in FIG. 1(c) There is).

As shown in the figure, the second substrate 12 is first placed on the support stand A, and then the first substrate 11 is superimposed on the second substrate 12. At this time, the contact pattern 17 on the first substrate 11
faces the contact pattern 17 on the second substrate 12.

Next, a heated pot breath B is pressed from above the first substrate 11 to separate the spacer layer 3 formed on the first substrate 11 and the spacer layer formed on the second substrate 12, as shown in FIG. Press 3 while heating. In this example, the hot press B was heated to 160°C and pressed for 4 seconds at a pressure of 10 kg/clT12 (in this example, the heat and pressing pressure applied to the pot press B were: 140~180℃, 10~2 okg/c
m” range is particularly preferred).

Here, since the vinyl chloride paint constituting the spacer layer 3 has thermoplasticity, by thermocompression bonding with the pot press B, the contact surfaces 35 of both spacer layers 3 are thermally welded and firmly fixed.

Note that the adhesive strength of the side substrates 11 and 12 in this example (
The force required to peel them off was approximately 1.6 kg/cm.

In the above manner, a predetermined gap (approximately 100 μm in this embodiment) is created between the first substrate 11 and the second substrate 12 due to the two spacer layers 3, 3. Then, the support base A and the hot press B are removed from FIG. 2(b) (a membrane switch having an appropriate spacing between the two contact patterns 17 and 17 is completed).

By the way, in the spacer layer 3 of this membrane switch,
A groove 33 as shown in FIG. 1(b) is provided. When the first substrate 11 is superimposed on the second substrate 12, this groove 33 is formed as shown in FIG. , the groove 33 formed in the spacer layer 3 on the first substrate 11 and the groove 33 formed in the spacer layer 3 on the second substrate 12 face each other, and a passage is formed by these two.

This passage is the exposed portion 31.3 shown in FIG. 2(b).
1, and one end thereof is open to the terminal portion 141 shown in FIG. 1(b).

If a passage like this is installed in a membrane switch,
The space C inside each membrane switch is electrically connected to the outside air at the terminal portion 141 by the passage. Therefore, even if the ambient temperature of the membrane switch changes, the atmospheric pressure can be maintained in the space C inside the membrane switch, so that the operation of the membrane switch will not be affected.

The reason why one end of this passage is opened at the terminal part 141 is to make the inside of the membrane switch waterproof even if the part of the membrane switch group made up of the first board 11 and the second board 12 is exposed to water. This is for the purpose of That is,
Even if the part of the membrane switch group made up of the first board 11 and the second board 12 gets wet, the space C inside each membrane switch is electrically connected to the outside air at the terminal part 141 part where there is no risk of getting wet. Therefore, water does not enter the space C, making it waterproof.

Note that when the membrane switch according to the present invention is used in a place not exposed to water, the passage constituted by the groove 33 may be opened anywhere.

FIG. 4 is a side sectional view showing another embodiment of the passageway.

As shown in the figure, in this embodiment, the groove 33 is
It is formed only on the spacer layer 3 on the substrate 12. Even with this configuration, a passage can be secured.

FIG. 5 is a sectional side view of a main part showing a membrane switch having another structure to which the present invention can be applied.

As shown in the figure, in this membrane switch, the second substrate 12 is made of a metal plate. An insulating layer 5 made of the same material as the spacer layer 3 is formed on the second substrate 12, and a contact pattern 17 is further formed thereon. Then, the spacer layer 3 of the first substrate 11 and the insulating layer 5 of the second substrate 12 are thermally welded using a hot press to complete the membrane switch.

In this membrane switch as well, as shown in FIG.
By forming a groove 33 as shown in FIG. 1, the space C in the contact pattern 17 and 17 can be electrically connected to the outside air.

Although the embodiments of the membrane switch according to the present invention have been described above in detail, the present invention is not limited thereto, and various modifications as described below are possible.

(2) In the embodiment of the membrane switch shown in FIG. 1 above, an example was shown in which the spacer layer 3 was formed on the entire flexible substrate 1 except for the exposed portion 31 around the contact pattern 17, the groove 33, and the terminal portion 141. The present invention is not limited to this, and the spacer layer may be formed in a predetermined portion of the substrate excluding at least the exposed portion around the contact pattern, and the groove may be formed to connect the exposed portion of the spacer layer with the outside of the spacer layer. As long as it is provided, it may have a structure like this.

■In each of the above embodiments, vinyl chloride paint was used as the paint for the spacer layer 3 (or insulating layer 5), but the present invention is not limited to this, and any thermoplastic resin paint may be used. can be any paint.

However, in the above example, the material for the spacer layer was 1 Spacer Resist This is because it is suitable for The reason is explained below.

That is, a typical resist layer is made of an epoxy or polyester resin mixed with an inorganic filler (such as Si) and a solvent to improve printability. On the other hand, XB-803 is a vinyl chloride paste resin containing an inorganic filler and a solvent, and the cured coating film has flexibility. Furthermore, since it does not contain an inorganic filler, it cannot tolerate a decrease in adhesive strength after thermocompression bonding.

On the other hand, since general adhesives (printing glue) have adhesive strength on the surface of the coating film after printing and hardening, it is necessary to apply a separator to this surface in advance.

On the other hand, X13-803 has no adhesive force on the surface of the cured coating film at room temperature, so there is no need to apply a separator to this surface in advance, and workability is good. Further, since common adhesives are sticky, they are not suitable for providing a specified thickness.

■ In each of the above embodiments, the flexible substrate 1 was made of a flexible polyester film, but the present invention is not limited to this, and it may be made of any material as long as it is a visible sheet. good.

(2) In the embodiment shown in FIG. 1, one flexible substrate is bent to form two substrates, but these two substrates may be formed from separate and independent substrates.

■In the embodiment shown in FIG. 1 above, both of the two substrates are flexible substrates, but the present invention is not limited to this, and one of the substrates is a rigid insulating substrate. It may also have a structure in which a circuit pattern having a contact pattern is formed and a spacer layer is provided thereon.

〔Effect of the invention〕

As explained in detail above, according to the membrane switch according to the present invention, the space formed by the exposed portion of the spacer layer inside the membrane switch is opened to the outside air through the passage formed by the groove. It has the excellent effect that the membrane switch is always maintained at atmospheric pressure, which prevents the membrane switch from malfunctioning.

[Brief explanation of drawings]

FIG. 1 is a plan view showing the procedure for creating a membrane switch according to the present invention, and FIG. 2 shows the first substrate 11 and the second substrate 1.
FIG. 3 is a side sectional view showing the state of the contact pattern 17 and 17 portions when bonding the two, FIG. 3 is a side sectional view showing the passage formed by the grooves 33 and 33, and FIG. 4 is another example. 5 is a side sectional view showing the main part of another membrane switch, FIG. 6 is a side sectional view showing the structure of a conventional membrane switch 80, and FIG. 7 is a side sectional view showing the structure of a conventional membrane switch 80. FIG. 17 is a fragmentary 178 side view showing the main parts of the membrane switch. In the figure, 11...first substrate, 12...second substrate, 16
...Circuit pattern, 17...Contact pattern, 3...
・Spacer layer, 31...Exposed portion, 33...Groove, 5.
...Insulating layer.

Claims (2)

[Claims] (1) A first substrate made of a flexible sheet and a second substrate made of a flexible sheet or a hard plate, a circuit pattern having a contact pattern is formed on each of the two substrates, and a circuit pattern is formed on each of the two substrates. A spacer layer is formed by applying a thermoplastic resin to at least a predetermined portion excluding the exposed portion around the contact pattern, and the spacer layers of both substrates are brought into contact by overlapping the two substrates so that the contact patterns of both substrates face each other. let me,
Furthermore, the membrane switch has the contact surface thermally welded, and at least one of the spacer layer on the first substrate and the spacer layer on the second substrate has an exposed portion of the spacer layer. A membrane switch characterized in that a groove is provided to connect the spacer layer to the outside. (2) A first substrate made of a flexible sheet and a second substrate made of a metal plate, a circuit pattern having a contact pattern is formed on the first substrate, and at least the periphery of the contact pattern is exposed. A spacer layer is formed by applying a thermoplastic resin to a predetermined portion of the second substrate except for the upper surface of the second substrate, and an insulating layer is formed by applying a thermoplastic resin to the upper surface of the second substrate, and a contact point is formed on the insulating layer. A circuit pattern having a pattern is formed, and both substrates are overlapped so that the contact patterns of both substrates face each other, and the spacer layer of the first substrate and the second substrate are
A membrane switch in which a contact surface of an insulating layer of a substrate is thermally welded, wherein at least one of the spacer layer and the insulating layer is provided with a groove for connecting an exposed portion of the spacer layer to outside air. A membrane switch characterized by: