JP2005209543A - Contact member for push-button switch - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a contact member which can be easily formed and whose contact property is good. <P>SOLUTION: In this contact member 1 for a push-button switch, a film-like metal layer 11 is formed on one face of a resin film 9, and a resin adhesive silicone rubber composition 8 is joined on the other face of the resin film 9. Therefore, an adhesive layer and a primer become unnecessary and the poor adhesion due to unevenness of application of them can be avoided. Since the resin film 9 is arranged between the film-like metal layer 11 and the resin adhesive silicone rubber composition 8, the resin film can prevent fatty acid ester from reaching the film-like metal layer even if the fatty acid ester resulting from sweat and dirt on fingers permeate the silicone rubber, and good continuity in switching can be maintained. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a member for a push button switch used for various electric devices and the like.

  Conventionally, in a push button switch used in various electric devices such as a push button switch such as a power window and a wiper in a passenger car and a key switch of a cellular phone, a contact member that contacts the electrode by pressing the push button is disposed. . By bringing this contact member into contact with the electrode, a conductive state is created and switching is performed.

Various contact members have been proposed in Patent Documents 1 to 3 as contact members for such pushbutton switches. For example, Patent Document 1 describes one using a silicone rubber kneaded with carbon, one in which a metal plate is attached to the tip of a contact member, or one in which the end surface of the contact member is formed of a flexible metal foil layer. Has been. The contact member on which the flexible metal foil layer is formed has a hard resin layer or a soft resin layer disposed between the silicone rubber layer which is the base end of the contact member and the flexible metal foil layer, and an adhesive layer or a primer layer. Is used to form a laminated structure.
JP 2003-109449 A Japanese Patent Laid-Open No. 5-274756 JP-A 63-96822

  However, these contact members have the following problems. That is, the contact member formed by kneading carbon into silicone rubber has a relatively high resistance value, so the use is limited, and fatty acid esters derived from finger sweat and dirt penetrate the silicone rubber, There was a problem of poor contact. In the contact member formed by attaching a metal plate to the tip of the contact member, there is a problem in that a contact failure is caused when an insulating foreign material enters between the metal plate and the electrode.

  Moreover, in the contact member in which the flexible metal foil layer described in Patent Document 1 is formed, there is a problem in that poor adhesion occurs when there is uneven coating on the adhesive or primer. For this reason, it takes a lot of man-hours to manage whether or not coating unevenness occurs.

  Then, an object of this invention is to provide the contact member which can be shape | molded more simply and has favorable contact property.

  The contact member for a push button switch according to the present invention is a contact member for a push button switch arranged to face an electrode, and includes a resin film, a thin metal layer formed on the electrode side surface of the resin film, and a resin. A silicone rubber portion that is bonded to a surface opposite to the surface of the film and has adhesiveness to the resin is provided.

  This pushbutton switch contact member has a structure in which a silicone rubber portion having adhesiveness to resin is bonded to the other surface of the resin film having a thin metal layer formed on the electrode side surface. Can be avoided, and adhesion failure caused by these coating unevenness can be avoided. Therefore, the yield is improved and the processing cost can be suppressed. In addition, since the resin film is disposed between the thin metal layer and the silicone rubber part, even if fatty acid esters derived from finger sweat or dirt permeate the silicone rubber, Reaching the thin metal layer can be prevented, the increase in electrical resistance of the thin metal layer due to fatty acid esters can be prevented, and a good conduction state in switching can be maintained. Furthermore, since the thin metal layer formed on the resin film can be deformed due to its flexibility, the contactability is impaired to the extent that some insulating foreign matter enters between the thin metal layer and the electrode. Absent.

  Further, the silicone rubber part is composed of 100 parts by weight of a thermosetting organopolysiloxane composition, 1 to 100 parts by weight of reinforcing silica fine powder, and an epoxy equivalent of 100 to 5000 g / mol and at least one aromatic in the molecule. A composition comprising a ring and 0.1 to 50 parts by weight of an organosilicon compound containing at least one Si—H group is preferred. By adopting such a composition for the silicone rubber part, the silicone rubber part can be securely bonded to the resin film.

  The thin metal layer is preferably a metal layer formed by vapor deposition, plating, or sputtering on the electrode-side surface of the resin film. Thereby, a thin metal layer can be reliably formed on the resin film, and a good conduction state in switching can be made possible.

  According to the contact member for a push button switch of the present invention, the formation is easy and the contact property is good.

  Hereinafter, preferred embodiments of a contact member for a pushbutton switch according to the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a perspective view of a cross section of a push button switch 2 using a contact member 1 according to an embodiment of the present invention, and FIG. 2 is a cross sectional view of the push button switch shown in FIG. As shown in FIGS. 1 and 2, the pushbutton switch 2 includes a columnar key top portion 3 that is pressed by an operator, a conical dome portion 4 that supports the key top portion 3, and the dome portion. 4 and a thin plate-like base portion 5 for supporting. The key top part 3, the dome part 4, and the base part 5 are integrally formed of silicone rubber. The contact member 1 is joined to the lower surface of the key top portion 3. Note that the shape of the key top portion 3 is not limited to a cylindrical shape, and may be another shape such as a prism.

  The contact member 1 is composed of three layers, and a resin adhesive silicone rubber composition 8 (silicone rubber portion), which is a silicone rubber imparted with adhesiveness to a resin, is joined to the lower surface of the key top portion 3. A resin film 9 is bonded to the lower surface of the resin adhesive silicone rubber composition 8, and a thin metal layer 11 is formed on the lower surface of the resin film 9.

  Further, a pair of electrodes 13 is provided on the circuit board 12, and the push button switch 2 is disposed on the circuit board 12 so that the electrode 13 is located immediately below the contact member 1. A wiring pattern 14 is electrically connected to the electrode 13.

  As shown in FIG. 2, in a state where the key top portion 3 is not pressed, the contact member 1 is separated from the electrode 13, but when the key top portion 3 is pressed, the dome portion 4 is moved downward. The contact member 1 moves downward and the thin-film metal layer 11 of the contact member 1 comes into contact with the electrode 13. By this contact, both electrodes 13 are in a conductive state, and it is detected that the switch is turned on. When the key top portion 3 is released from the press, the shape of the push button switch 2 is restored to the original state by the restoring force of the dome portion 4, and the thin film metal layer 11 of the contact member 1 is separated from the electrode 13. .

  Next, a method for manufacturing the contact member 1 will be described.

  First, a resin film 9 having heat resistance is prepared. Examples of the material of the resin film 9 include polyethylene terephthalate (PET), polyimide, polycarbonate (PC), polybutylene terephthalate (PBT), and alloy films thereof. The thickness of the resin film 9 is suitably about 10 to 300 μm. The thin film metal layer 11 is formed on one surface of the resin film 9 by vapor deposition, sputtering, plating, or the like using a metal such as gold, copper, nickel, aluminum, platinum, stainless steel, or chromium. . The thickness of the thin metal layer 11 is suitably 100 mm (10 nm) or more. The resin material of the resin film 9 and the metal material of the thin metal layer 11 may be appropriately selected from the viewpoints of heat resistance, resistance value, environmental resistance, and the like.

  Furthermore, the resin adhesive silicone rubber composition 8 is bonded to the other surface of the resin film 9, that is, the surface opposite to the surface on which the thin metal layer 11 is formed. This resin-adhesive silicone rubber composition 8 is composed of 100 parts by weight of a thermosetting organopolysiloxane composition, 1 to 100 parts by weight of reinforcing silica fine powder, and an epoxy equivalent of 100 to 5000 g / mol. It is a composition containing 0.1 to 50 parts by weight of an organosilicon compound containing one aromatic ring and at least one Si—H group (see JP 2002-201454 A). And joining of the resin film 9 and the resin adhesive silicone rubber composition 8 is performed by heat-hardening. Note that an appropriate amount of an addition reaction catalyst or an organic peroxide catalyst may be selectively added to the thermosetting organopolysiloxane composition as appropriate.

  Thus, the contact member 1 is completed by producing a three-layer composite sheet and then punching it with a punch having a predetermined diameter. According to such a contact member 1, an adhesive layer and a primer are not necessary, and adhesion failure caused by these coating unevenness can be avoided. Therefore, the yield is improved and the processing cost can be suppressed. In addition, since the resin film 9 is disposed between the thin metal layer 11 and the resin-adhesive silicone rubber composition 8, even if fatty acid esters derived from finger sweat or dirt pass through the silicone rubber, The resin film 9 can prevent fatty acid esters from reaching the thin metal layer 11, prevents an increase in electrical resistance of the thin metal layer 11 due to the fatty acid esters, and maintains a good conduction state in switching. can do. Furthermore, since the thin metal layer 11 formed on the resin film 9 can be deformed due to its flexibility, the thin film metal layer 11 is in contact with the thin metal metal layer 11 and the electrode 13 with some insulative foreign matter. Sex is not impaired.

  Hereinafter, a specific example will be shown and described.

  FIG. 3 is a diagram for explaining the manufacturing process of the contact member 1 and the manufacturing process of the push button switch 2 using the contact member 1 in the first embodiment.

  First, as shown in FIG. 3A, a polyethylene terephthalate film 9 having a thickness of 50 μm is prepared, and an aluminum layer 11 having a thickness of 1000 mm (100 nm) is formed on one surface of the PET film 9 by vapor deposition. did.

  And it arrange | positions in the engraving part (depth: 0.55 mm) of a sheet metal mold | die with the aluminum layer 11 of this PET film 9 down, and is opposite to the surface of the PET film 9 in which the aluminum layer 11 is formed Resin-adhesive silicone rubber X-34-1625A / B (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.) was poured onto the side surface, heated to 125 ° C. and subjected to compression molding for 3 minutes. As a result, as shown in FIG. 3B, a three-layer composite sheet 20 in which an aluminum layer 11 is formed on one side of the PET film 9 and a resin adhesive silicone rubber composition 8 is formed on the other side. Produced.

  Further, the composite sheet 20 was punched out with a punch having a diameter of 3 mm to produce a contact member 1 having a diameter of 3 mm and a thickness of 0.55 mm.

  Next, as shown in FIG. 3C, the contact member 1 was disposed in the concave portion 22 of the molding die 21 of the pushbutton switch cover member. A raw material in which 100 parts by weight of silicone rubber compound KE-941U (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.) and 2 parts by weight of cross-linking agent C-8 (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.) is mixed with a molding metal The cavity 21 of the mold 21 was filled and heat-cured at 170 ° C. for 10 minutes by compression molding to integrally mold the key top portion 3 and the contact member 1. FIG. 3D is a cross-sectional view of the molded pushbutton switch cover member. As shown in FIG. 3 (d), the silicone rubber compound KE-941U filled in the cavity 23 of the molding die 21 is cured, so that the key top portion 3, the dome portion 4, and the base portion 5 are formed. Yes. Further, the contact member 1 is joined to the lower surface of the key top portion 3, and the aluminum layer 11 is located on the lower side.

  The contact resistance value of the aluminum layer 11 in the manufactured contact member 1 was a good value of 20Ω. In addition, a keystroke durability test was performed using a load of 200 g and a keystroke speed of 3.3 times / second as test conditions. As a result, even when the key was pressed 200,000 times, separation of each layer in the contact member 1 was not recognized, and a stable switch function was maintained. From this, it was confirmed that the pushbutton switch 2 provided with the contact member 1 produced in Example 1 has excellent practicality.

  Next, Example 2 will be described. In addition, since the structure of each member in Example 2 is the same as the structure of each member in Example 1, it demonstrates with reference to FIG. 3 used by description of Example 1. FIG.

  As shown in FIG. 3A, a gold (Au) layer 11 having a thickness of 200 mm (20 nm) was formed on one side of a polycarbonate film 9 having a thickness of 100 μm by vapor deposition.

  On the other hand, 100 parts by weight of resin-adhesive silicone rubber KE-153U (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.) and 0.5% of addition system cross-linking agent C-25A (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.) Part by weight, 2.0 parts by weight of the cross-linking agent C-25 / B (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.) and 1.0 part by weight of the adhesive component X-93-3046 are mixed to form a sheet. It was processed into.

  Then, the resin adhesive silicone rubber composition, which is placed in the engraved portion (depth: 0.55 mm) of the sheet mold with the metal layer 11 of the PC film 9 on the lower side and processed into a sheet shape, It was piled on the inner PC film 9, heated to 125 ° C., and compression molded for 3 minutes. As a result, as shown in FIG. 3B, a three-layer composite sheet 20 in which the gold layer 11 was formed on one side of the PC film 9 and the resin adhesive silicone rubber composition 8 was formed on the other side was produced. .

  Further, the composite sheet 20 was punched with a φ3 mm punch to produce a contact member 1 having a φ3 mm and a thickness of 0.55 mm.

  Next, as shown in FIG. 3 (c), the contact member 1 is disposed in the recess 22 of the molding die 21 of the pushbutton switch cover member 24, and silicone rubber compound KE-941U (manufactured by Shin-Etsu Chemical Co., Ltd.) Name) A raw material in which 2 parts by weight of a cross-linking agent C-8 (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.) is blended in 100 parts by weight is filled in the cavity 23 of the molding die 21 and compression molded at 170 ° C. for 10 minutes. By the method, the key top part 3 and the contact member 1 were integrally formed. Here, as shown in FIG. 3 (d), the silicone rubber compound KE-941U filled in the cavity 23 of the molding die 21 is cured, so that the key top portion 3, the dome portion 4, and the base portion 5 are formed. Is formed. Further, the contact member 1 is bonded to the lower surface of the key top portion 3, and the gold layer 11 is positioned on the lower side. In this way, the push button switch cover member 24 is formed.

  The contact resistance value of the gold layer 11 in the molded contact member 1 was a suitable value of 4Ω. In addition, as a result of performing a keystroke durability test with a load of 200 g and a keystroke speed of 3.3 times / second as a test condition, even when keystrokes were performed 200,000 times, no separation of each layer in the contact member 1 was observed, and a stable switch function Was holding. From this, it was confirmed that the pushbutton switch 2 provided with the contact member 1 manufactured in Example 2 also has excellent practicality.

It is the perspective view which took the cross section of the pushbutton switch using the contact member which concerns on one Embodiment of this invention. It is sectional drawing of the pushbutton switch shown in FIG. It is a figure for demonstrating the manufacturing process of the contact member in Example 1, 2, and the manufacturing process of the pushbutton switch using this contact member. FIG. 3A is a side view of a resin film having a thin metal layer formed on one side. FIG. 3B is a side view of a resin film in which a thin-film metal layer is formed on one side and a resin-adhesive silicone rubber composition is joined on the other side. FIG.3 (c) is sectional drawing which shows the state which has arrange | positioned the contact member in the shaping die of the cover member for pushbutton switches. FIG. 3D is a cross-sectional view of the molded pushbutton switch cover member.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Contact member, 2 ... Pushbutton switch, 8 ... Resin adhesive silicone rubber composition, 9 ... Resin film, 11 ... Thin film metal layer.

Claims (3)

A contact member for a pushbutton switch disposed opposite to the electrode,
A resin film;
A thin metal layer formed on the electrode side surface of the resin film;
A contact member for a pushbutton switch, comprising: a silicone rubber portion bonded to a surface opposite to the surface of the resin film and having adhesiveness to the resin.   The silicone rubber part comprises 100 parts by weight of a thermosetting organopolysiloxane composition, 1 to 100 parts by weight of reinforcing silica fine powder, and an epoxy equivalent of 100 to 5000 g / mol and at least one aromatic ring in the molecule. The contact member for a pushbutton switch according to claim 1, wherein the composition comprises 0.1 to 50 parts by weight of an organic silicon compound containing at least one Si—H group.   The push button switch according to claim 1 or 2, wherein the thin metal layer is a metal layer formed by vapor deposition, plating, or sputtering on a surface of the resin film on the electrode side. Contact member.

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