JP4131756B2 - Membrane switch - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a membrane switch formed on the surface of a film-like flexible substrate and provided with a pair of electrodes facing each other.
[0002]
[Prior art]
As disclosed in Japanese Utility Model Publication No. 4-46335, a conventional membrane switch includes a contact made of a pair of electrodes provided facing each other through a predetermined space formed on an insulating sheet, and the contact. Is formed at the end and is composed of a wiring pattern laminated via an insulating sheet. Each of the wiring patterns was formed on an insulating resin film, and the resin film was bonded to each other through an insulating sheet.
[0003]
[Problems to be solved by the invention]
In recent years, electronic devices with membrane switches have come to be used in various places, and products with membrane switches have appeared in addition to electronic devices, and the number of products that require membrane switches has increased due to their convenience. ing.
[0004]
In general membrane switches, all electrodes have the same switching action. Therefore, even in the same electronic device, when different switching functions are required, it is necessary to use membrane switches formed separately.
[0005]
The present invention has been made in view of the above problems of the prior art, and an object of the present invention is to provide a membrane switch having different switch functions and good electrical conductivity.
[0006]
[Means for Solving the Problems]
The membrane switch of the present invention includes a pair of insulating resin films, an upper electrode wiring pattern formed on one end of the resin film and having an upper electrode on the end, and formed on the other end of the resin film. A lower electrode wiring pattern having a lower electrode, and an insulating sheet provided between the upper electrode wiring pattern and the lower electrode wiring pattern. A plurality of through holes having different sizes are formed at positions where the upper electrode and the lower electrode of the insulating sheet face each other, and the upper and lower electrodes on the pair of resin films sandwich the through holes. A switch that faces and can be contacted and separated by pressing is formed. The wiring pattern for the upper electrode and the wiring pattern for the lower electrode , excluding the switch portion, are formed as independent circuit wiring patterns for each of the plurality of through holes having different sizes in a state where the pair of resin films are laminated. The upper electrode wiring pattern and the lower electrode wiring pattern are provided in parallel so that the projection positions do not overlap each other with the insulating sheet interposed therebetween . The insulating sheet between the wiring patterns is a membrane switch in which a space communicating with the through hole is formed.
[0007]
The switches provided in the wiring patterns are located close to each other for the switches of different wiring patterns. Each of the wiring patterns and the switches is a laminate of a conductive paint layer and a carbon paint layer. The insulating resin film uses polyethylene naphthalate or the like. Further, a space communicating with the through hole is formed between the wiring patterns, and connected to air holes provided at predetermined positions.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings. A membrane switch according to an embodiment of the present invention is composed of an insulating resin film 10 made of polyethylene naphthalate (PEN) or the like as shown in FIG. Wiring patterns 12a, 12b, and 12c are formed. In addition, on the surface of the other resin film 14 facing the resin film 10, three electrically independent lower electrode wiring patterns 16a, 16b, and 16c are formed.
[0009]
Circular upper electrodes 18a, 18b, and 18c and lower electrodes 20a, 20b, and 20c are formed at respective ends of a plurality of predetermined portions provided on the wiring patterns 12a, 12b, 12c, 16a, 16b, and 16c. Has been. An insulating sheet 22 such as polyethylene terephthalate (PET) is interposed between the wiring patterns 12a, 12b, 12c, 16a, 16b, and 16c. The insulating sheet 22 is formed with a plurality of through holes 24a, 24b, and 24c at predetermined ends, and the upper electrodes 18a, 18b, and 24c are sandwiched between the through holes 24a, 24b, and 24c, as shown in FIG. 18c and the lower electrodes 20a, 20b, and 20c face each other to form thin film switches 26a, 26b, and 26c.
[0010]
Here, the wiring pattern 12a and the switch 26a form a switch circuit 28a. Similarly, the wiring pattern 12b and the switch 26b form a switch circuit 28b, and the wiring pattern 12c and the switch 26c form a switch circuit 28c. . Each of the switch circuits 28a, 28b, 28c is electrically independent and exhibits a switching action.
[0011]
As shown in FIGS. 1 and 2, the switches 26 a, 26 b, and 26 c are provided in close proximity so as not to overlap each other via the insulating sheet 22, and have different sizes and pressing forces that can be contacted and separated. As shown in FIG. 3, the wiring patterns 12a, 12b, 12c, 16a, 16b, and 16c are provided in parallel so that the projection positions do not overlap with the surfaces of the resin films 10 and 14 facing each other. The insulating sheet 22 between the wiring patterns 12a, 12b, 12c, 16a, 16b, and 16c has a space 30 that communicates with the through holes 24a, 24b, and 24c between the electrodes 18a, 18b, 18c, 20a, 20b, and 20c. The end of the space 30 communicates with an air hole (not shown) provided in the resin film 10 in the vicinity of the end of the switch circuits 28a, 28b, 28c connected to other circuits.
[0012]
Each wiring pattern 12a, 12b, 12c, 16a, 16b, 16c is formed by laminating a conductive paint layer 32 containing a metal such as silver or copper and a carbon paint layer 34. The conductive paint layer 32 is a resin. Since the electrodes 18a, 18b, 18c, 20a, 20b, and 20c in the switches 26a, 26b, and 26c are provided directly on the films 10 and 14, the carbon coating layer 34 serves as a contact point.
[0013]
Here, the polyethylene naphthalate forming the resin films 10 and 14 is less likely to release the oligomer of the low polymer, and the oligomer does not enter the inside of the switch circuits 28a, 28b, and 28c formed on the surface, so that good conduction is achieved. Maintain sex for a long time. Moreover, the resin film which does not discharge | release oligomers, such as polyetherimide and a polyimide, can be used as a resin film which does not discharge | release an oligomer similarly to polyethylene naphthalate. These resins are currently more expensive than polyethylene naphthalate, but can be used due to the following various cost reductions.
[0014]
Since the switch circuits 28a, 28b, and 28c of this embodiment are provided with switches 26a, 26b, and 26c having different sizes close to each other, when the pressure is applied, the upper electrode and the lower electrode can be connected under the pressing force. Only a switch is connected, and a detection circuit connected to the switch and the switch circuit acts. Further, since the air in the through holes 24a, 24b, 24c provided in the switches 26a, 26b, 26c passes through the space 30 and enters or exits from the air holes due to the contact / separation of the switches 26a, 26b, 26c, the membrane switch Is easily and securely connected, and the switches 26a, 26b, and 26c are not damaged.
[0015]
Since this membrane switch closes due to different pressing forces, it is installed on a car seat, for example, and used as a sensor to detect what kind of person or object is placed on the seat by the pressure on the seat. Can do. For example, the switch 26c of the through hole 24c having the largest diameter is turned on for all the weights of a small load or more, and the switch 26b of the through hole 24b having the smallest diameter is turned on when an adult having a predetermined weight or more is seated. The switch 26a having an intermediate diameter 24a is set to be turned on when the weight of the child is higher than the weight. Thus, depending on which switch is being used, the person or object located on the seat can be detected, and the operation of the seat belt or the airbag can be adjusted accordingly.
[0016]
Note that the number of switch circuits, the size of the switch, and the like are appropriately selected in accordance with the electronic device incorporating the membrane switch. In addition, a plurality of sets of switches having different switch circuits as shown in FIG. 1 may be formed on a single membrane switch and provided on a vehicle seat or the like as described above. Those sets can be appropriately set.
[0017]
In addition, the membrane switch of the present invention is not limited to the above-described example, and the above-described embodiment is merely an example of a position embodiment, and the shape and position of a wiring pattern, an electrode, and the like are appropriately changed. Is also possible. Also, other resin films that do not generate oligomers may be used as long as they have good electrical conductivity, and the electrode and wiring pattern paints also have electrical conductivity, and can be changed as appropriate. Is possible.
[0018]
【The invention's effect】
The membrane switch of the present invention is provided with independent wiring patterns connected to different circuits and the like, and the contacts are closed by different pressing forces, and can be used for detection of various different pressing forces. Furthermore, since each wiring pattern and switch are provided close to each other, a plurality of detection functions can be simultaneously acted upon by pressing from the outside.
[0019]
In addition, by using polyethylene naphthalate for the insulating resin film, it is possible to prevent an insulator such as an oligomer from entering the electrode and to ensure good electrical conductivity for a long period of time.
[Brief description of the drawings]
FIG. 1 is a partial perspective view showing a switch of a membrane switch according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view taken along the line AA of FIG. 1 showing the switch of the membrane switch of this embodiment.
3 is a cross-sectional view taken along the line BB in FIG. 1 showing a wiring pattern of the membrane switch of this embodiment.
[Explanation of symbols]
10, 14
Resin films 12a, 12b, 12c Upper electrode wiring patterns 16a, 16b, 16c Lower electrode wiring patterns 18a, 18b, 18c Upper electrodes 20a, 20b, 20c Lower electrodes 22 Insulating sheets 24a, 24b, 24c Through holes 26a, 26b , 26c Switch 28a, 28b, 28c Switch circuit 30 Space 32 Conductive paint layer 34 Carbon paint layer

Claims (3)

A pair of insulating resin films, an upper electrode wiring pattern formed on one end of the resin film and having an upper electrode at the end, and a lower electrode formed on the other end of the resin film and having a lower electrode at the end And an insulating sheet provided between the upper electrode wiring pattern and the lower electrode wiring pattern, and a plurality of different positions are provided at positions where the upper electrode and the lower electrode of the insulating sheet face each other. A through hole having a size is formed, and the upper electrode and the lower electrode on the pair of resin films face each other across the through hole, and a switch that can be contacted and separated by pressing is formed. wiring pattern for the upper electrode wiring pattern and the lower electrode in a state where the pair of the resin film is laminated, the wiring path for each independent circuit for each through hole of said plurality of different sizes Together are formed as over emissions, the upper electrode wiring pattern and the lower electrode wiring pattern, the projection position by sandwiching the insulating sheet is provided parallel to so as not to overlap each other, the wiring pattern for the upper electrode A membrane switch in which a space communicating with the through hole is formed in the insulating sheet between the lower electrode wiring patterns. The switches provided in the wiring patterns are arranged close to each other for the switches of different wiring patterns, and the wiring patterns and the switches are formed by laminating a conductive paint layer and a carbon paint layer. membrane switch of claim 1, wherein is obtained by.   The membrane switch according to claim 1 or 2, wherein the insulating resin film is polyethylene naphthalate.

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