JP2001076583A - Connector mounting structure for membrane switch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the electrical conduction reliability between connector terminals and switch wires and to improve the structural and mechanical durability of a connector connection section in a connector-mounted membrane switch. SOLUTION: First electrodes 5, second electrodes 6, and first wires 7 and second wires 8 connecting the electrodes 5, 6 are formed by screen printing or the like on the opposite faces of the first insulating film 2 and second insulating film 3 of this membrane switch 1. Part of the second wires 8 are guided to the back side of the second insulating film 3 as wire connecting wires 11 and accumulated on a wire connection section 12 together with the rest of the second wires 8. The tip section of a tail section 13 extending only from the second insulating film 3 is folded, and a reinforcing member 14 is pinched, stuck, and fixed on the inside face. A connector 16 is mounted on this fold section 15, the external terminals of the connector 16 are connected to the wire connecting wires 11 and the like via an anisotropic conductive adhesive and covered with a sealing resin agent, thereby their connection portion is reinforced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a connector mounting structure of a membrane switch which is used by being incorporated into a keyboard of a personal computer and has a tail portion provided with a connector for connection to another board or the like.
The present invention relates to a connector mounting structure of a membrane switch which can improve the reliability of electrical conduction between a terminal of a connector and a wiring of a switch and a structural durability and can reduce a thickness of a connector connecting portion.

[0002]

2. Description of the Related Art In recent years, membrane switches have been frequently used in electronic devices equipped with thin electronic circuit boards. The connection between the membrane switch and the main body substrate is made by accumulating wiring at the end of an extension portion (hereinafter, referred to as a tail portion) extending from the membrane switch, and press-contacting the front end portion with the main body substrate to establish conduction. There are known a method of taking the electric current, a method of establishing electrical continuity by fitting the tip of the tail portion to a connector of the main body substrate, and the like.

[0003] On the other hand, a board-to-board connector (hereinafter, referred to as a BB connector) corresponding to a reduction in the thickness of a keyboard used for a keyboard of a personal computer (hereinafter, referred to as a personal computer). The use of a so-called connector to connect the wiring of the membrane switch to the circuit of the PC board has been increasing. FIG.
FIG. 1 is a schematic view showing such a conventional membrane switch.

As shown in FIG. 5, a conventional membrane switch 50 is disposed on a support plate (not shown) made of a metal plate such as Fe (iron) and Al (aluminum), and is made of, for example, polyethylene terephthalate (PET). The first insulating film 51 and the second insulating film 55 made of) are overlapped with an insulating spacer 60 interposed therebetween. On the surface of the first insulating film 51 on the second insulating film 55 side, a plurality of first electrodes 52 made of Ag (silver) and first wirings 53 connecting between the first electrodes 52 are formed by screen printing or the like. hand,
It constitutes a first electrode sheet. Similarly, on the surface of the second insulating film 55 on the side of the first insulating film 51, a plurality of second electrodes 54 made of Ag are formed on the second wiring 56 connecting the second electrodes 54 and the first insulating film 51. The first wiring connection wiring 57 connected to the first wiring 53 is formed by screen printing or the like to form a second electrode sheet. An opening 59 is formed in the insulating spacer 60 at a position where the first electrode 52 and the second electrode 54 face each other, and the upper and lower electrodes 52 and 54 come into contact via the opening 59 to perform a switching operation. It has become. The first electrode sheet, the insulating spacer 60, and the second electrode sheet are strictly aligned by using a jig or the like, and then a fusion portion formed by ultrasonic waves oscillated from the fusion horn. Glued at 61. Further, the second wiring 56 and the first wiring connecting wiring 57 are integrated in a tail portion 58 of the membrane switch 50.

FIG. 6 is a schematic sectional view showing a tail portion of a conventional membrane switch. As shown in FIG. 6, a tail portion 58 of the conventional membrane switch 50 has a second insulating film 55 as a base material, and has a second wiring 56 and a first wiring connecting wiring (not shown) formed on the surface thereof. Have been. Except for the tip portion 62, a protective tape 63 for protecting the wiring from mechanical damage is covered with an adhesive 64. The upper surface of the tip portion 62 where the wiring of the tail portion 58 is exposed is connected to the lower surface of the connection board 65 made of glass epoxy and the anisotropic conductive film 66.
And are electrically connected. The anisotropic conductive film 66 is made of a polymer as a main material and is a connection material having an adhesive, conductive and insulating function. For example, when thermocompression bonding is performed, conductivity is obtained in the film thickness direction. It shows electrical anisotropy that an insulating property is obtained in a direction perpendicular to the thickness direction. Further, on the upper surface of the connection board 65, a BB female connector 101 is provided.

The BB female connector 101 is provided with a connector concave portion 101a into which the convex portion of the male connector is fitted. A plurality of inter-connector terminals 101d are provided on a surface of the connector concave portion 101a facing the tail portion base, and a plurality of inter-connector terminals 101c are provided on the opposite surface. Further, below the BB female connector 101, a plurality of external terminals 101e that are electrically connected to the inter-connector terminals 101c and 101d are provided. Terminals 101c and 101d between connectors are external terminals
101e, is electrically connected to the second wiring 56 and the first wiring connecting wiring 57 via the anisotropic conductive film 66 and the wiring connecting them.

In the conventional membrane switch 50 constructed as described above, for example, the B
-When the B male connector is mounted, the wiring of the membrane switch 50 is electrically connected to the circuit of the PC board by connecting the BB female connector 101 and the BB male connector. Can be. The connection method using the BB connector has high structural connection strength, high electrical conduction reliability, and excellent detachability.

[0008]

However, in the above-described conventional membrane switch 50, the tail portion 58 and the connection substrate 65 are bonded and fixed by the anisotropic conductive film 66 having low adhesive strength. , The connection strength of that part is low. For this reason, the wiring of the membrane switch and
There is a problem that the reliability of electrical conduction with the terminals of the BB female connector is low. Further, depending on how to handle the board of the personal computer and the membrane switch 50 during the assembling operation, a pressure load is applied to the BB connector, so that there is a problem that the connector and the tail portion 58 are broken.

The BB female connector 101 is connected to the connection board 6.
Since the connector is connected to the tail portion 58 via 5, there is a disadvantage that the thickness of the connector connection portion is increased.

The present invention has been made in view of such a problem, and can improve the reliability of electrical conduction and the structural durability between a terminal of a connector and a switch wiring. An object of the present invention is to provide a membrane switch capable of reducing the thickness of a connector connection portion.

[0011]

A connector mounting structure for a membrane switch according to the present invention is obtained by stacking a pair of flexible sheets comprising a first insulating film and a second insulating film via an insulating spacer. A first electrode and a second electrode are formed on opposing surfaces of the pair of flexible sheets, respectively, and the first wiring and the first wire connected to the first electrode respectively on the opposing surface are formed. A second wiring connected to the second electrode is formed, and an opening for forming a contact portion is formed at a predetermined position of the insulating spacer, and the contact portion in the thickness direction of the flexible sheet is formed. When a load is applied, the first electrode and the second electrode facing each other at the opening position are in contact with the switch main body, and the first wiring and the second wiring extend from the switch main body and have a small number of The connector mounting structure of the membrane switch, wherein a connector is directly mounted on the tip of the tail portion of the membrane switch having a tail portion that is partially integrated and routed, and the tip portion of the tail portion is folded back. A folded portion, a reinforcing member interposed inside the folded portion and adhesively fixed to an inner surface of the folded portion, and a reinforcing resin adhered and fixed to an outer surface of the folded portion with a sealing resin. It is characterized by having a wiring routed to the tip of the tail portion and a connector to which an external terminal is bonded via a conductive adhesive.

In the present invention, the terminal of the connector and the first and second wirings are bonded via a conductive adhesive, and the bonded portions are reinforced by a sealing resin. Therefore, their connection strength can be improved. In addition, since the connector is directly mounted on the folded part at the tip of the tail part using a conductive adhesive and a sealing resin, the base part to be connected is strengthened, eliminating the need for a connection board that was required conventionally. become. Therefore, the thickness of the connector connection portion can be reduced.

[0013] Further, since a reinforcing member such as a reinforcing plate is provided between the folded portion and the tail portion,
Since the strength of the folded portion and the tail portion can be further improved, breakage such as breakage around the mounting portion of the connector can be prevented.

Further, the tail portion is formed so as to extend only from the second insulating film, and a part of the second wiring is integrated on a surface on which the second wiring is formed, and the second wiring is formed. The other part of the wiring is routed through the first through-hole to form an integrated connection wiring, and the second wiring or the connection wiring is formed at a tip end of the tail part. Are guided to the same surface through the through hole of the connector, and connected to the external terminals of the connector from both sides of the connector, the second wiring and the connection wiring integrated in the folded portion have one of them. Since the upper surface of the folded portion and the other can be routed on the lower surface of the folded portion, wiring around the connector can be simplified, and the width of the folded portion and the tail portion can be reduced.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a membrane switch according to an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a perspective view showing a membrane switch according to one embodiment of the present invention.

The membrane switch 1 has a switch body 1a and a tail section extending from the switch body 1a.
The switch body 1a is formed by stacking a pair of flexible sheets made of a first insulating film 2 and a second insulating film 3 such as an insulating resin film such as a PET film via an insulating spacer 4. It is constituted by doing. On the opposing surfaces of the first insulating film 2 and the second insulating film 3, a first electrode 5 and a second electrode 6 each formed of a conductive pattern made of, for example, Ag are formed by a method such as screen printing. . Contact part 9 of insulating spacer 4
An opening 10 is formed at a position corresponding to
When the load is applied via the first 10
The electrode 5 and the second electrode 6 are in contact with each other. The first electrode 5 and the second electrode 6 are respectively connected to a first wiring 7 and a second wiring 8 similarly formed by a method such as screen printing. The first wiring 7 and the second wiring 8 are formed as a common wiring pattern in a state where the films are developed, for example, when the insulating films 2 and 3 are formed by folding one film into two. May be. After the first insulating film 2, the insulating spacer 4, and the second insulating film 3 are strictly aligned by using a jig or the like, the first insulating film 2, the insulating spacer 4, and the second insulating film 3 are fused at the spacer joining fusion portion 19 where no electrodes, wirings, etc. are formed. Ultrasonic fusion using a horn (not shown). Note that, in this example, a part of the second wiring 8 is guided as a wiring connection wiring 11 to the back side of the second insulating film 3 via a first through hole (not shown). The wiring 11 and the second wiring 8 are integrated in the wiring connection unit 12. The tail part 13 extends only from the second insulating film 3, and the tail part 13 has a folded part 15.
The connector 16 is mounted on the folded portion 15.

FIG. 2 is a plan view showing a connector mounting structure in the folded portion 15 of the tail portion 13, and FIG.
It is AA sectional drawing of. As shown in FIGS. 2 and 3, in the tail portion 13 in which the folded portion 15 is formed, for example, one surface of the second insulating film 3 is
However, a second wiring 8 is provided on the other surface. The wiring 11 for wiring connection and the second wiring 8 are covered with a protective tape 20 made of PET via an adhesive (not shown) to protect them from mechanical damage.
The folded portion 15 is formed by bending the tip end of the tail portion 13 at a bending rate of about R 0.5 mm, and a plate-like reinforcing member 14 is sandwiched inside the folded portion 15, and The lower surface is adhesively fixed to the inner surface of the folded portion 15 by the adhesive 21. The second wiring 8 is guided as a wiring connection wiring 11 ′ on the same surface as the wiring connection wiring 11 through a second through hole 17 formed through the second insulating film 3 in the thickness direction thereof. Has been. The ends of the wirings 11 and 11 ′ are connected to the connector 1 on the second insulating film 3.
Located on both sides of 6. A connector 16 is provided so as to be aligned with the ends of these wirings 11, 11 '. Since the connector 16 is a female connector, a concave portion 16a is provided for fitting the convex portion of the male connector, and a locking projection for improving the connection strength with a pair of male connectors (not shown) is provided on one outer wall. 16b is provided.

A plurality of inter-connector terminals 16c and 16d are provided on opposing surfaces of the connector recess 16a, respectively. The inter-connector terminals 16c and 16d are electrically connected to external terminals 16e and 16f extending outward from below the connector 16. Connected.
External terminals 16e and 16f are connected to ACF (Anisotropic Condu
ctive Film), ACP (Anisotropic Conductive Paste)
Wirings 11 and 1 via anisotropic conductive adhesive 23 such as
It is electrically connected to 1 '. The sealing resin material 24 is provided so as to cover the exposed portions of the external terminals 16e and 16f and the wirings 11 and 11 'for wiring connection, and has an effect of improving the connection strength between the connector 16 and the folded portion 15. . When a connector (not shown) of another substrate to be paired with this connector 16 is fitted and connected, the terminals 16c and 16d between the connectors come into contact with the corresponding terminals (not shown) between the connectors. A circuit on another substrate and the membrane switch 1 are electrically connected.

In the membrane switch 1 of this embodiment having the above-described structure, the connection between the folded portion 15 and the connector 16 is adhered by the anisotropic conductive adhesive 23, and the adhesive strength is increased by the sealing resin 24. Because of the reinforcement, the connection strength between the terminal of the connector 16 and the wiring can be improved. Therefore, the reliability of electrical conduction between the terminal of the connector 16 and the wiring can also be improved.

Further, since the connector 16 is directly mounted on the folded portion 15, the connection board 65 and the like required in the conventional membrane switch 50 become unnecessary, and the thickness of the connector connection portion can be reduced. it can. In addition, the conventional tail
The material for the connection portion reinforcing tape and the like used for improving the connection strength between the connection board 58 and the connection board 65 and the step of attaching work can be omitted, and the parts and work costs can be reduced. .

Further, according to the experiment of the present inventor, the result that the mechanical strength was excellent was obtained. For example, FIG.
In the connector connection part pull-out strength measurement, which is a nondestructive test shown in (a), the tail part 71 of the membrane switch having the connector mounted on the experimental board fixing jig 70 is fitted and fixed, and pulled in the directions of the vectors A and B. Pull strength when
As shown in FIG. 6C, the connector connection portion 90 is about 3 to 7 (kgf / piece) and is a destructive test shown in FIG.
° In the peel (peel) strength measurement, an experimental substrate fixing jig 72
Adhesively fix the tail 73, pull in the direction of vector C,
The 90 ° peel strength when the connector connection portion 74 was broken was about 7 to 9 (kgf / piece). That is, as shown in FIG. 3 (c), although the tensile strength (A, B) at which the connector comes off is smaller than the breaking strength, the tensile strength of the connector connection portion of the conventional membrane switch is 1 (kgf).
/), Which is advantageous in mechanical strength. For this reason, for example, reliability such as mechanical stability and durability against connector attaching / detaching work in inspection of a membrane switch or the like is high.

In this embodiment, the tail portion 13 is formed by extending the second insulating film 3, but the tail portion 13 may be formed by extending the first insulating film 2. Further, the folding direction of the tail portion 13 may be reversed. Furthermore,
The connector 16 may be mounted at a position opposite to the mounting position of the tip of the tail portion 13 shown in FIG.
In addition, a BB connector is used as a connector, but this is not a limitation as long as the same effect as the gist of the present invention can be obtained. For example, an anisotropic conductive adhesive or the like can also achieve conduction only in the thickness direction. If so, various forms are conceivable.

[0023]

As described above, according to the present invention,
The connection strength between the terminal of the connector of the membrane switch and the switch wiring can be improved by bonding the tail part, the folded part, and the reinforcing member, so that the electrical conduction reliability and the structural durability are improved. Can be done. Further, since a connection board is not required for connection between the connector and the membrane switch, the thickness of the connector connection portion can be reduced.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a membrane switch according to an embodiment of the present invention.

FIG. 2 is a plan view showing a connector mounting structure in a folded portion of a tail portion of the membrane switch.

FIG. 3 is a sectional view taken along line AA of FIG. 2 at a tail portion and a folded portion of the membrane switch.

FIG. 4 is a diagram for explaining a durability test of a connector connection portion of the membrane switch.

FIG. 5 is a schematic view showing a conventional membrane switch.

FIG. 6 is a schematic sectional view showing a tail portion of the membrane switch.

[Explanation of symbols]

1,50 membrane switch, 2,51 first insulating film, 3,55 second insulating film, 4,60 insulating spacer, 5,52 first electrode, 6,54 second electrode, 7, 53 ... first wiring, 8,56 ... second wiring, 9 ... contact part, 10 ... opening,
11, 11 ': Wiring for wiring connection, 12: Wiring connection part, 13: Tail part, 14: Reinforcing member, 15: Folded part, 16: Connector, 17: Second through hole, 19: Fusion for spacer joining Attachment part, 20 ... Protective tape, 23 ... Anisotropic conductive adhesive.

Claims (2)

[Claims] 1. A pair of flexible sheets made of a first insulating film and a second insulating film are formed by superimposing them via an insulating spacer, and a pair of flexible sheets are formed on opposing surfaces of the pair of flexible sheets. A first electrode and a second electrode are formed, and a first wiring connected to the first electrode and a second wiring connected to the second electrode are formed on the facing surface, respectively. An opening for forming a contact portion is formed at a predetermined position of the insulating spacer, and the first electrode facing the opening portion position when a load in the thickness direction of the flexible sheet is applied to the contact portion at the contact portion. And a switch body contacting the second electrode, and a tail extending from the switch body and at least a part of the first wiring and the second wiring are integrated and routed to the tip. Membrane with A connector mounted structure of a membrane switch in which a connector is directly mounted on the tip of the tail portion of the tail switch, wherein the folded portion is formed by folding the tip portion of the tail portion, and is interposed inside the folded portion. A reinforcing member adhesively fixed to the inner surface of the folded portion; a wiring and a conductive adhesive adhesively fixed to the outer surface of the folded portion with a sealing resin and routed to the tip of the tail portion; And a connector to which an external terminal is adhered through the connector. 2. The tail portion is formed so as to extend only from the second insulating film. A part of the second wiring is integrated on a surface on which the second wiring is formed, and the tail portion is formed. The other part of the wiring is routed through the first through hole to form an integrated connection wiring, and the second wiring or the connection wiring is a second part at the tip of the tail part. 2. The connector mounting structure for a membrane switch according to claim 1, wherein said connector is guided to the same surface through said through hole, and connected to external terminals of said connector from both sides of said connector.