WO2019087627A1

WO2019087627A1 - Contact member and contact rubber switch, and method for manufacturing contact member

Info

Publication number: WO2019087627A1
Application number: PCT/JP2018/035912
Authority: WO
Inventors: 彬人竹内
Original assignee: 積水ポリマテック株式会社
Priority date: 2017-11-06
Filing date: 2018-09-27
Publication date: 2019-05-09
Also published as: JPWO2019087627A1

Abstract

The purpose of the present invention is to provide: a contact member that has superior reliability and durability even for long-term use and that has superior conductivity; and a contact rubber switch provided with said contact member. This contact member 1 for conductive contact with an electrode C of a circuit board P is provided with a metal plate 12 having on the surface thereof: a plurality of island-shaped projection parts 16, a recessed part 17 that surrounds the projection parts 16, and sloped surfaces 17c which are formed from the outer circumferential edge of each projection part 16 to the bottom surface of the recessed part, wherein all of the projection parts 16 are arranged to the inside and away from an outer circumferential edge E of the metal plate 12.

Description

Contact member, contact rubber switch and method of manufacturing contact member

The present invention relates to a contact member which contacts and leaves an electrode provided on a circuit board to turn on and off the switch, and a contact rubber switch having the contact member.

2. Description of the Related Art Conventionally, members for push button switches called contact rubber switches and contact rubbers are widely used in electronic devices and in-vehicle devices. The push button switch member has a pressing portion, a base portion, and a thin flexible portion connected to the base portion surrounding the side surface of the pressing portion. When the pressing portion is pressed, the thin flexible portion is bent and deformed. Then, the conductive contact portion formed below the pressing portion contacts or separates from the electrode (or the substrate contact) provided on the circuit board, thereby turning on / off the circuit.

Such push button switch members themselves have been used for a long time, but in recent years not only the demand for downsizing, but also the high conductivity of the contact portion that can cope with a large current, and under various adverse conditions and for a long time Reliability and durability have come to be regarded as important for achieving stable performance even during continuous use.

However, if foreign substances such as dust are mixed in due to a poor use environment or long-term use, there is a risk that the stability as a switch that repetitive keying failure becomes poor. In addition, depending on the conditions of use, moisture or various corrosive gases (for example, hydrogen sulfide (H ₂ S) or sulfur dioxide gas may be used if a metal plate such as a copper plate or a nickel white plate is used as the conductive contact portion from the viewpoint of high conductivity. (Sulfur oxide) (SO ₂ ), hydrogen chloride (HCl), chlorine (Cl ₂ ), hydrogen fluoride (HF), nitrogen dioxide (nitrogen oxide) (NO ₂ ), ammonia (NH ₃ ), ozone (O ₃ )), it may be corroded by being exposed to sea breeze etc., and it becomes impossible to maintain conductivity.

Among these problems, a technique in which reliability is improved by devising the contact portion against contamination of foreign matter is described in JP-A-2004-134241 (Patent Document 1) and JP-A-7-288054 (Patent Document 2). It is done.

In JP-A-2004-134241 (Patent Document 1), foreign matter smaller than the cross-sectional area of the recess is made to enter the recess by forming an independent recess or a continuous recess in the metal plate as the contact portion by etching. Conduction is ensured, and foreign matter larger than the cross-sectional area of the recess can be ensured by easily deforming the metal plate by the action of the thin portion of 50 μm or less due to the formation of the recess.

Further, in JP-A-7-288054 (Patent Document 2), a metal film of 0.01 to 1 μm is provided in the contact portion, and an independent thick metal portion of 50 to 500 μm is provided on the metal film. The flexibility of the metal film allows it to be flexibly deformed even if there is foreign matter, and contact with the contact point is made with a thick metal part, and is resistant to repeated use without enduring long-term use.

JP, 2004-134241, A Japanese Patent Application Laid-Open No. 7-288054

However, although the technique described in Japanese Patent Laid-Open No. 2004-134241 (Patent Document 1) shows a solution to the contamination of foreign matter, it does not particularly describe the problem of metal corrosion and its solution. In fact, since the technique of performing gold plating on the tip surface of the convex portion is shown, although the tip portion can resist corrosion of metal, there is a concern that the inside of the ditch is corroded. In addition, as for the countermeasure against foreign matter contamination, the technical idea thinks that the concave portion and the concave portion which are independent are considered equally, and the influence of the difference in the shape of the concavo-convex portion is not mentioned at all. As apparent, the cause of the deformation of the metal plate is only the result of the formation of the thin portion of 50 μm or less by the formation of the recess.

However, in Japanese Patent Application Laid-Open No. 2004-134241 (Patent Document 1), a keying test is performed 500 times as a test of conductive failure for repeated use, and the usage period assumed at the time of filing of this document is so much It is not long and the requirements for long-term use and corrosion resistance are not as stringent as it is today.

On the other hand, even in the technique described in Japanese Patent Application Laid-Open No. 7-288054 (Patent Document 2), although a solution to the contamination of foreign matter is indicated, the problem of metal corrosion and the solution are not particularly described. In fact, thick metal parts are formed by gold plating, and there is no corrosion problem in this part. However, since a metal appropriate to the application is used for the metal film portion, there is also a concern that corrosion may occur. Moreover, the influence by the shape of the thick metal part is not shown at all also with respect to the cause of securing the conductivity regarding the contamination prevention measures, and this document only refers to the flexibility of the metal film formed on the thin film.

Furthermore, in any of the above documents, there is no description on the aspect to be avoided on the uneven surface of the contact portion, or deformation or dropout of the contact portion due to repeated use, and a technique that can endure reliability and durability is sufficient. It can not be said that

Therefore, the object of the present invention is to provide a contact member having high reliability and durability even for long-term use and having high conductivity, and a contact rubber switch including the contact member. is there.

In order to achieve the above object, the present invention is configured as follows. That is, according to the present invention, contact members in conductive contact with the electrodes of the circuit board are formed from a plurality of island-like convex portions, concave portions surrounding the convex portions, and the outer peripheral edge of each convex portion to the bottom surface of the concave portions It comprises a metal plate having an inclined surface on the surface, and all of the convex portions are arranged on the inner side avoiding the outer peripheral edge of the metal plate.

In the contact member in conductive contact with the electrodes of the circuit board, the surface of the metal plate is provided with a plurality of island-shaped convex portions, concave portions surrounding the convex portions, and the outer peripheral edge of each convex portion to the bottom surface of the concave portions And an inclined surface formed over the end. Although the foreign matter is likely to be caught between the electrode of the circuit board and the concave part in the acutely pointed concave part, the metal plate of the present invention has an inclined surface, so foreign matter may be mixed even if foreign matter is mixed between the electrode and the concave part. The sloped surface facilitates movement to the central portion of the recess. As a result, the metal plate can be easily deformed even when the foreign matter is sandwiched, and the contact member can be easily brought into contact with the electrode. Moreover, the electroconductive film which coat | covers the surface of a metal plate can make it hard to produce problems, such as peeling and drop-off | omission. And since a contact member is provided with such a metal plate, high conductivity can be secured.

Further, in the present invention, all of the convex portions are disposed on the inner side away from the outer peripheral edge of the metal plate, but contrary to such a form, in the case where the convex portions also exist on the outer peripheral edge of the metal plate Asperities formed by the convex portions and the concave portions occur on the outer peripheral edge, and depending on the location, a thin and pointed protrusion may appear. In such a case, the keying of the contact rubber switch may damage the electrodes of the circuit board, or the metal protrusion may be broken, resulting in the occurrence of fine foreign particles. In addition, the current may be discharged at once between the electrodes of the circuit board and the metal protrusion to cause sparks. However, since all of the convex portions are disposed on the inner side away from the outer peripheral edge of the metal plate, there may be no convex metal pieces, which may occur when the convex portions exist on the outer peripheral edge of the metal plate Various contact failures can be prevented in advance.

The contact member may be configured to include a conductive film covering the surface of the metal plate. Since the contact member is provided with a conductive film covering the surface of the metal plate, the surface of the metal plate is protected by the conductive film to enhance the corrosion resistance of the metal plate and to improve the reliability for long-term use it can.

Further, in the direction along the outer peripheral edge, the adjacent convex portions can be configured as contact members disposed at substantially equal intervals. In the direction along the outer peripheral edge, adjacent convex portions are arranged at substantially equal intervals, so the probability that foreign matter tries to enter into any part of the surface of the metal plate becomes equal. For this reason, even if foreign matter enters, it does not concentrate in a specific place and is not dispersed, and conduction is achieved without reaching a state where the contact of the contact member with the circuit board is prevented. And the possibility of contact failure can be reduced.

In the present invention, the convex portion is formed in a circular shape, an oval shape, an oval shape, a three-forked shape, a four-forked shape or a V-shape in a plan view and the line end is rounded. Can be configured. The shape of the convex portion on the surface of the metal plate is a circle, an ellipse, an oval, or a three-, four- or V-shape in plan view, and the line end is rounded. The width of the convex portion can be narrowed in shape. Therefore, even if the foreign matter is present, it does not stay in the convex portion, and it is easy to roll in the concave portion, so that the metal plate is easily deformed. In addition, when the shape has a corner, sparks may occur to the electrodes of the circuit board. However, since any of the shapes has a rounded shape, such sparks are unlikely to occur.

The concave portion may be configured to have one or more linear concave grooves extending linearly without hitting any of the convex portions from one end to the other end of the outer peripheral edge of the metal plate. Since the recess is provided with one or more linear grooves extending straight from one end to the other end of the outer periphery of the metal plate from the one end to the other, the metal plate is used as a folding line with this linear recess. By deforming so as to bend, as many convex portions as possible can be made easy to be in contact with the electrode of the connection object.

The one or more linear grooves may be configured to have a plurality of linear grooves not parallel to one another. According to this, a fold line is generated for each linear concave groove, and the metal plate is deformable so as to fold the metal plate at a plurality of fold lines, thereby bringing as many convex parts as possible into contact with the electrode of the connection object It can be made easy.

In the present invention, the thickness of the bottom surface portion of the concave portion of the metal plate can be 10 to 90 μm. Since the plate thickness at the bottom of the concave portion of the metal plate is 10 to 90 μm, the metal plate is easily bent flexibly, and even if foreign matter is mixed, the bending deformation of the metal plate is maintained to make the contact member unlikely to cause conduction failure. be able to.

The present invention can be configured such that it has a rubber portion fixed to the back surface of the metal plate, and the rubber portion has a JIS-A hardness of 70 or less. Since the rubber portion fixed to the back surface of the metal plate is provided and the JIS-A hardness of the rubber portion is 70 or less, the back surface of the metal plate can be protected by the flexible rubber portion. Further, by having the rubber portion, the metal plate can be returned to the original state if it is separated from the foreign matter even if the metal plate is deformed by coming into contact with the foreign matter. Further, the contact member is low in hardness and flexible and can be easily brought into contact with the electrode on the circuit board. In addition, manufacture in the case of incorporating in a contact rubber switch is easy.

The present invention can also be configured as a contact rubber switch having a pressing portion, a base portion, a thin flexible portion connected to the base portion surrounding the side surface of the pressing portion, and any one of the contact members. Since the pressing portion, the base portion, and the thin flexible portion connected from the pressing portion to the base portion are provided, the switch can be used as a push button switch that turns the switch on and off by pressing the pressing portion. In addition, since any one of the contact members is provided, a contact rubber switch having high reliability and durability even for long-term use and high conductivity can be obtained.

The present invention also relates to a method of manufacturing a contact member including a metal plate in conductive contact with an electrode of a circuit board, wherein a plurality of island-like convex portions are formed on the surface on one side of a metal plate capable of taking a plurality of metal plates. A concave portion surrounding the convex portion and an inclined surface extending from an outer peripheral edge of each convex portion to a bottom surface of the concave portion, and the cutting position for cutting out the metal plate from the metal plate material does not overlap the convex portion A manufacturing method of a contact member characterized in that a recess is cut and the metal plate is punched out of the metal plate material.

In the manufacturing method according to the present invention, since the concave portion having the inclined surface continuously connected to the bottom from the outer peripheral edge of the plurality of island-shaped convex portions is formed on one surface of the metal plate, subsequent conductive coating formation is easy Thus, the conductive coating film is easily introduced uniformly into the recess, and it is difficult to form a thin portion of the conductive coating film which is easily peeled off in repeated use. In addition, since the recess is cut to cut out the metal plate from the metal plate so that the cutting position where the metal plate is cut out from the metal plate does not fall on the protrusion, it is likely to occur when cutting the protrusion It is possible to prevent the occurrence of burrs. Therefore, manufacturing the contact member which can prevent that a circuit board is damaged by generating an unusual shape caused by a burr or the like, or that an electric current is discharged at once by an irregular portion coming into contact with the circuit board to generate a spark. be able to.

Furthermore, in the present invention, masking is performed to form the plurality of island-shaped convex portions, chemical etching is performed, and the concave portion having the inclined surface continuous with the bottom surface gently from the outer peripheral edge of the convex portion is formed. After the masking is removed, the entire surface of the metal plate is subjected to a chemical etching process to provide a method of manufacturing a contact member in which the boundary between the surface of the convex portion and the concave portion is rounded.

In the manufacturing method of the present invention, since the concave portion having the inclined surface which is continuous to the bottom gently from the outer peripheral edge of the convex portion is formed by the chemical etching process, the subsequent formation of the conductive coating is easy. The conductive coating easily enters uniformly, and it is difficult to form a thin-walled portion of the conductive coating which is likely to be peeled off in repeated use. Further, since the concave portion is formed by chemical solution etching, the side surface of the concave portion is not formed in a deep and steep shape, and it is easy to form a gentle inclined surface.

Then, after removing the masking, the surface of the metal plate is further subjected to a chemical etching process, so that the corners of the convex portions can be formed in a rounded shape, which makes the foreign particles more difficult to enter and damage the circuit board even by repeated use. hard.

According to the contact member and the contact rubber switch of the present invention, the metal plate has high conductivity and is flexible and easily bent even when foreign matter such as dust is caught, and many convex portions are brought into conductive contact with the electrode It is possible. Furthermore, it is difficult to generate a spark due to the current being discharged at once.

It is a model longitudinal cross-sectional view of a contact point rubber switch. It is an expansion explanatory view of the metal plate part seen from the surface direction of a contact member (plan view). It is an expansion explanatory view equivalent to FIG. 2 which shows the other form of a metal plate. It is an expansion explanatory view equivalent to FIG. 2 which shows the other form of a metal plate. It is an expansion explanatory view equivalent to FIG. 2 which shows the other form of a metal plate. It is an expansion explanatory view equivalent to FIG. 2 which shows the other form of a metal plate. It is an expansion explanatory view equivalent to FIG. 2 which shows the other form of a metal plate. It is an expansion explanatory view equivalent to FIG. 2 which shows the other form of a metal plate. It is an expansion explanatory view equivalent to FIG. 2 which shows the other form of a metal plate. It is an expansion explanatory view equivalent to FIG. 2 which shows the other form of a metal plate. It is an expansion explanatory view equivalent to FIG. 2 which shows the other form of a metal plate.

The contact member of the present invention, the contact rubber switch including the same, and the method of manufacturing the contact member will be described in detail based on the embodiments. FIG. 1 shows a schematic longitudinal sectional view of a contact member and a contact rubber switch according to one embodiment. The contact rubber switch 10 includes a contact member 1 which repeats contact and non-contact with an electrode (substrate electrode) C on the circuit board P, a pressing portion 2 which receives a pressure for switch operation, and the circuit board P. And a thin flexible portion 4 connected to the base portion 3 so as to surround the side surface of the pressing portion 2.

Of the contact rubber switch 10, the pressing portion 2, the base portion 3 and the thin flexible portion 4 excluding the contact member 1 are formed of a rubber-like elastic body such as silicone rubber. On the other hand, the contact member 1 is formed of a metal plate 12, a conductive film 13 covering the surface of the metal plate 12, and optionally a rubber portion 14, as shown in the partial enlarged view of FIG.

The metal plate 12 constituting the contact member 1 has a disk shape when the surface shape is viewed from the circuit board P side (plan view), and a plurality of convex portions 16 formed in an island shape on the surface facing the electrode C And a recessed groove 17 as a "recess". The recessed groove 17 has an inclined surface 17 c which is continuous with the bottom surface 17 b from the side surface 17 a shared with the convex portion 16. Further, all of the convex portions 16 are disposed on the inner side avoiding the outer peripheral edge E of the metal plate 12.

The surface shape of the metal plate 12a as an example among the metal plates 12 is shown in FIG. In the present embodiment, the convex portion 16 (16a) is formed of a three-forked shape and a cross-shaped one, and a peripheral portion thereof is a recessed groove 17. If the convex portion 16 has a three-forked shape or a cross shape, for example, when the length from the center to the end is compared with a circular convex portion having the same length, the spread in the width direction is equivalent to that Since the area can be reduced, the possibility (probability) of the foreign matter rolling into the recessed groove 17 is higher than that the foreign matter remains on the surface S of the convex portion 16, and a conduction failure is less likely to occur. Also, the line end of the three-protruded or cross-shaped convex portion 16 has a rounded shape to prevent the occurrence of sparks due to the sharp convex portion hitting the circuit board P, and repeated use Also the durability against

All of the convex portions 16 are disposed on the inner peripheral side avoiding the outer peripheral edge E of the metal plate 12, and in the direction along the outer peripheral edge E of the metal plate 12, adjacent three-branch convex portions 16 are It arranges at equal intervals, and a plurality of convex parts 16 are arranged intermittently. Since the convex portion 16 is spaced apart from the outer peripheral edge E of the metal plate 12, the boundary portion between the convex portion 16 and the concave groove 17 is not formed on the outer peripheral edge E of the metal plate 12, By having a convex portion on the outer peripheral edge E, it is possible to prevent sparks from occurring, and it is possible to prevent the convex portion of the outer peripheral edge E from being deformed and the durability being deteriorated. Further, when the convex portion has a shape continuously connected along the outer periphery, it becomes difficult to be discharged to the outside of the contact member 1 when foreign matter gets in, but it is intermittently provided along the outer periphery, There is no inconvenience. In addition, when the convex portion continues along the outer periphery, the area of the surface of the convex portion increases and the possibility of sandwiching foreign matter with the circuit board P increases, but the convex portion 16 is discontinuous along the outer periphery Therefore, the area of the convex surface does not become too large.

Further, the concave groove 17 of the metal plate 12 has one or more linear concave grooves 17 d which extend linearly without hitting any of the convex portions 16 from one end to the other end of the outer peripheral edge E of the metal plate 12. It is preferable that the number of such linear concave grooves 17d is one or more and plural. If there is no linear concave groove 17d, the bending center of the metal plate 12 does not exist, and the metal plate 12 is hardly bent and deformed, so that a conduction defect easily occurs when large foreign matter is mixed. On the other hand, the reason why it is preferable that even one linear groove 17d exists is that the metal plate 12 can be deformed so as to bisect the linear groove 17d as a folding line, and if there are a plurality of metal grooves, the metal plate 12 This is because there will also be a plurality of places that divide 2 into two, and it becomes easy to flexibly cope with various aspects in which the number and size of the foreign substances caught are different.

The size of the metal plate 12 can be a disc-shaped diameter of 2.0 to 5.0 mm. In addition, the size of the convex portion 16 is set such that the length in the maximum length direction in plan view is 0.1 mm to 2.0 mm, or 5.0 to 40% of the diameter of the metal plate 12 can do. The shortest distance in the direction from the outer peripheral edge E of the metal plate 12 to the center of the metal plate 12 can be 0.05 mm or more. In one embodiment of the metal plate 12a shown in FIG. 2, the diameter of the metal plate 12a is 3.0 mm, and the shortest distance from the outer peripheral edge E of the metal plate 12a to the three-pronged convex portion 16a is 0.15 mm. Can be, which is the preferred form.

The thickness of the bottom of the recess of the metal plate 12, that is, the thickness of the metal plate 12 of the recess 17 is preferably 10 to 90 μm, and the depth of the recess 17 in the metal plate 12 The ratio of the height of the groove to the thickness of the recessed groove 17 is preferably 25:75 to 75:25, and more preferably 40:60 to 60:40. If the thickness of the metal plate 12 at the recessed groove 17 portion is thinner than 10 μm, a hole may be formed in the metal plate 12 and it may be larger than 50 μm, but if it is thicker than 90 μm, the metal plate 12 becomes difficult to bend.

In addition, when the depth of the recessed groove 17 is smaller than 25% of the thickness of the metal plate 12, the effect of forming the recessed groove 17 may not be generated, and the depth of the recessed groove 17 is the thickness of the metal plate 12 If the depth of the groove 17 is greater than 75%, the thickness of the recessed groove 17 may be too thin and the metal plate 12 may be broken. That is, by setting the ratio of the depth of the recessed groove 17 to the thickness of the recessed groove 17 to 25:75 to 75:25, more preferably 40:60 to 60:40, the metal plate 12 can maintain durability and bend. Both ease can be improved.

The thickness of the thickest portion of the metal plate 12 including the height of the convex portion 16 of the metal plate 12 and the thickness of the concave groove 17 is preferably 100 μm or less. The reason is that by setting the thickness of the metal plate 12 to 100 μm or less, it can be flexibly bent.

Different examples of the surface shape of the metal plate 12 are shown in FIGS. Among these figures, the surface shape of the metal plate 12 shown in FIGS. 3 to 7 is an example in which the convex portion 16 is formed in a circular shape in plan view. Among these, the metal plate 12b shown in FIG. 3 has one convex portion 16b at the center of the metal plate 12b and six convex portions 16b at equal intervals along the outer peripheral edge E. The metal plate 12c shown in FIG. 4 has no convex portion at the center of the metal plate 12c, and has three convex portions 16c at equal intervals along the outer peripheral edge E. The

metal plates

12d and 12e shown in FIGS. 5 and 6 also have no convex portion at the center of the metal plate 12, and have eight

convex portions

16d and 16e at equal intervals along the outer peripheral edge E, respectively. It has four

convex parts

16d and 16e on the circumferential side respectively. The difference between the

metal plates

12d and 12e is that the arrangement of the four

protrusions

16d and 16e on the inner peripheral side with respect to the eight

protrusions

16d and 16e on the outer peripheral side is different. The metal plate 12f shown in FIG. 7 has no convex portion at the center of the metal plate 12f, has 16 convex portions 16f at equal intervals along the outer peripheral edge E, and also has eight convex portions 16f, Furthermore, it has four convex parts 16f inside.

The metal plate 12 shown in FIGS. 3 to 7 has a diameter of 3.0 mm as one embodiment, and the shortest distance from the outer peripheral edge E of the metal plate 12 to the circular convex portion 16 on the outer peripheral side And the diameter of one convex portion 16 of the circular shape is in the range of 0.1 to 2.0 mm, or in the range of 3 to 35% of the diameter of the metal plate 12. It is preferable to do. The reason is that when the diameter of the convex portion 16 is too large, foreign matter is easily held between the convex portion 16 and the circuit board P, and when the diameter is too small, the concave groove 17 is also shallow and the metal plate 12 is difficult to bend. It is from. The diameter of one convex portion 16b is 0.3 mm in the metal plate 12b of FIG. 3, the diameter of one convex portion 16c is 1.0 mm in the metal plate 12c of FIG. 4, and the one convex portion 16f in the metal plate 12f of FIG. A diameter of 0.1 mm is one of the preferred embodiments.

When the metal plate 12d shown in FIG. 5 is compared with the metal plate 12e shown in FIG. 6, while the distance between the convex portions 16d of the metal plate 12d is almost the same, the metal plate 12e is at the distance between the convex portions 16e. There are big and small. If the distance between the convex portions 16 is large or small, the difference between the portion where foreign matter easily enters and the portion where it is difficult to enter is generated, so the foreign matter is relatively easy to enter. Therefore, the metal plate 12d in which the distance between the convex portions 16 is equal is more preferable than the metal plate 12e because the easiness of entering and discharging the foreign matter is improved.

The metal plate 12g shown in FIG. 8 is an example having four oval convex portions 16g in addition to the circular convex portion 16g. Further, the metal plate 12h of FIG. 9 is an example having a quadrangular convex portion 16h and an oval convex portion 16h. The metal plate 12i of FIG. 10 is an example having a four-pronged convex portion 16i at the center and a V-shaped convex portion 16i at the periphery. Similar to the metal plate 12i of FIG. 10, the metal plate 12j of FIG. 11 also has a quadruple-shaped convex portion 16j at the center and a V-shaped convex portion 16j around the V-shaped convex portion 16j. The long side of the shape has a shape along the outer peripheral edge E. In each of the metal plates 12 shown in FIGS. 8 to 11, the convex portions 16 along the outer periphery are provided at equal intervals apart from the outer peripheral edge E, respectively.

And the line end of any convex part 16 shown in FIGS. 9-11 is rounded, and the contact member 1 is a circuit board including the circular or oval convex part 16 shown in FIGS. 3-8. Even if the electrode C of P is inclined and contacted at various angles, the outer peripheral edge E of the metal plate 12 can contact at many points, and a large current flows locally and short circuit is unlikely to occur.

As a material of the metal plate 12, a conductive metal such as copper, iron, aluminum, nickel, tin, chromium, titanium, gold, silver, or an alloy containing at least one of them can be used. Examples of the alloy include iron alloys such as stainless steel, copper alloys such as nickel, brass, beryllium copper, aluminum alloys such as duralmin, and nickel alloys. By using the metal plate 12, even if foreign matter is present between the contact member 1 and the electrode C, the contact member 1 can be brought into contact with the electrode C and made conductive by the bending of the metal plate 12. Other than metals, there are conductive materials such as carbon, graphite, and conductive resin, but they have lower conductivity than metals and there is a risk of scraping or falling off due to repeated use. And

The conductive film 13 is provided on the surface of the metal plate 12 in order to improve the weather resistance and the corrosion resistance of the metal plate 12. More specifically, a metal film or a conductive resin film can be mentioned as the conductive film 13. Examples of the material of the metal film include gold, nickel, chromium, tin, zinc and the like which have weather resistance and corrosion resistance, and a film made of these materials can be formed by plating or vapor deposition. The thickness of the metal film is preferably 0.1 to 2 μm. If the metal film is thicker than 2 μm, the flexibility of the contact portion is deteriorated and the cost is increased. On the other hand, if the metal film is thinner than 0.1 μm, the metal plate 12 is exposed and easily corroded due to the ease of wear. For example, by using nickel and silver on the metal plate 12 and performing nickel plating followed by gold plating, a metal film having high adhesion can be formed.

In the conductive resin film, a resin film obtained by blending conductive powder such as metal or carbon in a polymer material to give conductivity, polythiophene type PEDOT-PSS (poly (3,4-ethylenedioxythiophene) doped Examples thereof include conductive polymer films such as with poly (styrenesulfonate) and polyaniline. As the polymer material, resin materials such as acrylic resin, urethane resin, silicone resin, epoxy resin, and polyester resin can be used. As the conductive powder, conductive carbon powder such as carbon black, graphite or carbon nanotube can be used. Among these conductive resin films, a resin film containing a carbon-based conductive powder is preferable to a resin film containing a metal-based conductive powder because of its corrosion resistance and low cost.

The conductive resin film preferably has a thickness of 3 to 15 μm. When the film thickness of the conductive resin film is larger than 15 μm, the conductivity of the contact member 1 is significantly reduced as compared with the case of only the metal plate 12 in which the conductive film 13 is not provided. On the other hand, if the film thickness of the conductive resin film is smaller than 3 μm, the metal plate 12 is exposed and easily corroded due to the occurrence of pinholes and the ease of abrasion.

The resistance value of the contact member 1 is preferably 2.4 Ω or less, more preferably 2.0 Ω or less. The reason is that the current flowing to the automotive equipment using a 12 V power supply is in the range of 2 to 100 A, and about 5 A is often used. In addition, this resistance value prepares a 0.6 mm pitch comb electrode substrate having a width of 300 μm of one linear electrode and a gap of 300 μm between adjacent linear electrodes, while the contact portion Is a resistance value when pressed at a speed of 10 mm / min and a load of 9.8 N.

The contact member 1 may be formed of a metal plate 12 having a conductive film 13, but preferably includes a rubber portion 14. By laminating the metal plate 12 with the metal plate 12, the rubber portion 14 returns to the original shape even if the metal plate 12 is deformed, and absorbs the pressing force to prevent the metal plate 12 from being overloaded. Further, by fixing the rubber portion 14 to the back surface of the metal plate 12 in advance, it is easy to be integrated with the rubber-like elastic body to be the contact rubber switch 10 thereafter, and the manufacturing of the contact rubber switch 10 becomes easy.

The rubber portion 14 may be made of the same material as that of the rubber-like elastic body that is the material of the contact rubber switch 10, but may be made of a different material. However, in the case of different materials, it is preferable to use synthetic rubbers of a type that can be fixed by integral molding. Examples of the material used for the rubber portion 14 include silicone rubber, ethylene propylene rubber, nitrile rubber, urethane rubber, fluororubber and the like. Silicone rubber is preferable as the material of the rubber portion 14 in that the compression set is small.

The hardness of the rubber portion 14 is preferably a low-hardness rubber having a JIS-A hardness of 70 or less, since it becomes the contact member 1 which is easily bent and easily contacts the electrode C, and a JIS-A hardness of about 30 is more preferable. The JIS-A hardness is a hardness measured by a type A durometer in accordance with JIS-K6253.

The method for forming the concave groove 17 of the metal plate 12 includes, in addition to cutting, forging, pressing, and electrical discharge machining on a flat metal plate material, chemical solution etching (wet etching) performed with a chemical solution such as acid or alkali. On the contrary, although the convex part 16 may be formed on the flat metal plate 12, the gentle slope continuous with the side face 17a from the portion which becomes the bottom face 17b of the concave groove 17 by plating, evaporation, electroforming etc. It is more difficult to form the surface 17c, and it is preferable to form the recessed groove 17 from a flat metal plate material.

Furthermore, in order to form the concave groove 17 and the convex part 16 with high accuracy even among the methods of forming the concave groove 17 and to form the concave groove 17 and the convex part 16 with high accuracy, the convex part 16 is left as a non-processed part using a masking method. It is preferable to use a chemical solution etching method. The use of laser etching, dry etching such as photo etching, or plasma etching containing a reactive gas can not provide a smooth inclined surface 17c, as shown in FIG. 2 of JP-A-2004-134241. It is difficult to adopt such an etching method because such sharp and sharp grooves are formed. On the other hand, when the convex portion 16 is left by using the masking method, the surface S of the convex portion 16 maintains the flat and smooth surface of the metal plate material, so surface contact when this surface S contacts the electrode C Therefore, reliable conduction can be obtained.

Chemical solution etching is performed by applying masking to a portion left as the convex portion 16 in the metal plate in advance and then immersing in the chemical solution to perform etching. However, the etching liquid is not applied to the masked edge portion, and the convex portion There are corners at the outer edge of the 16th. On the other hand, after removing the masking after the etching process, it is possible to form roundness at the boundary where the surface S of the convex portion 16 turns to the concave groove 17 by further etching the entire surface. By forming a roundness on the outer peripheral edge of the convex portion 16, foreign matter can be easily slipped into the concave groove 17 from the surface S of the convex portion 16 and can be prevented from remaining in the surface S of the convex portion 16 to cause conduction failure.

The formation of the conductive resin film is preferably performed by a method in which a solvent or the like is added to the conductive resin to form a coating. The reason is that a thin conductive resin film can be formed. As a method of application, various coating methods such as spray coating, and various printing methods such as screen printing and bar coater coating can be adopted.

The fixation between the metal plate 12 and the rubber portion 14 can be performed by insert molding in which a metal plate material is disposed in a molding die of a rubber member such as the rubber portion 14 or the like. It is preferable that the fixation of the both be performed after the chemical etching process using an acid alkali is performed on the surface of the metal plate material. The reason is to prevent an adverse effect such as the rubber portion 14 touching the chemical solution. A primer or an adhesive may be applied between the metal plate and the rubber portion 14. In addition, after the metal plate 12 is cut out from the metal plate material, it may be fixed to the rubber portion 14.

In order to cut the metal plate 12 into a predetermined shape from the metal plate material, cutting using a punching die or a cutting blade, laser processing, or the like can be used. At that time, a positioning jig or the like may be used together. At the time of this cutting process, the concave groove 17 is cut so that the metal plate can be cut out so that the cutting position for cutting out the metal plate from the punching die, the cutting blade or the metal plate does not fall on the convex portion 16 Is preferred. The reason is to prevent the convex portion 16 from being formed on the outer peripheral edge E of the metal plate 12 which has been cut out.

The contact member 1 thus obtained is put in a mold for molding a contact rubber switch, and integrally molded (insert molding etc.) to obtain a contact rubber switch 10. At this time, if the rubber portion 14 is laminated on the back surface of the metal plate 12, the rubber portion 14 is crushed in the mold to produce a packing effect, and uncured for forming the contact rubber switch on the surface side of the metal plate 12. It is possible to prevent the rubber-like elastic body from coming around.

Since the recessed groove 17 is smoothly continuous from the side surface 17 a to the bottom surface 17 b, the conductive film 13 is uniformly formed in the recessed groove 17. Further, the boundary between the surface S of the convex portion 16 and the side surface 17 a also becomes gentle, and peeling of the conductive film 13 at the end portion of the surface S of the convex portion 16 hardly occurs. Therefore, the contact member 1 can have high durability and little variation in conductive performance.

The above embodiment is an exemplification of the present invention, and modifications of the embodiment or addition of known techniques, combinations and the like can be made without departing from the spirit of the present invention, and these techniques are also within the scope of the present invention. It is included in

DESCRIPTION OF SYMBOLS 10 contact rubber switch 1 contact member 2 pressing part 3 base part 4 thin-walled

flexible part

12, 12a-12j metal plate 13 conductive film 14

rubber part

16, 16a-16j convex part 17 recessed groove

17a side surface

17b bottom surface 17c inclined surface 17d Straight groove C electrode (substrate electrode)
P Circuit board S Convex part surface E Outer edge of metal plate

Claims

The contact member in conductive contact with the electrode of the circuit board
A metal plate having on its surface a plurality of island-like convex portions, concave portions surrounding the convex portions, and inclined surfaces formed from the outer peripheral edge of each convex portion to the bottom surface of the concave portions,
A contact point member characterized in that all of the convex portions are disposed inside away from the outer peripheral edge of the metal plate.
The contact member according to claim 1, further comprising a conductive coating that covers the surface of the metal plate.
The contact member according to claim 1 or 2, wherein the convex portions adjacent to each other in the direction along the outer peripheral edge are arranged at substantially equal intervals.
The said convex part is circular, an elliptical shape, an oval shape, or a three-forked shape, a four-forked shape, or a V-shape in planar view, and the line end is formed in a rounded shape. The contact member according to any one of claims 3 to 10.
The concave portion includes one or more linear concave grooves extending linearly from one end to the other end of the outer peripheral edge of the metal plate without hitting any of the convex portions. The contact member according to item 1.
The contact member according to any one of claims 1 to 5, further comprising a plurality of straight grooves not parallel to each other as the one or more straight grooves.
The contact member according to any one of claims 1 to 6, wherein a thickness of the bottom surface portion of the concave portion of the metal plate is 10 to 90 μm.
The contact member according to any one of claims 1 to 7, further comprising a rubber portion fixed to the back surface of the metal plate, wherein the rubber portion has a JIS-A hardness of 70 or less.
A pressing unit,
And the base
A thin flexible portion connected from the pressing portion to the base portion;
A contact rubber switch comprising the contact member according to any one of claims 1 to 8.
In a method of manufacturing a contact member including a metal plate in conductive contact with an electrode of a circuit board,
On the surface on one side of a metal plate material from which a plurality of metal plates can be taken, a plurality of island-like convex portions, concave portions surrounding the convex portions, and an inclined surface extending from the outer peripheral edge of each convex portion to the bottom surface Manufacturing the contact member characterized in that the recess is cut and the metal plate is cut out from the metal plate so that the cutting position where the metal plate is cut out from the metal plate does not overlap the convex portion. Method.
The plurality of island-like convex portions are masked, and chemical etching is performed to form the concave portion having the inclined surface continuous with the bottom gently from the outer peripheral edge of the convex portions, and the masking is removed. The method for manufacturing a contact member according to claim 10, wherein the entire surface of the metal plate is further subjected to chemical etching after that, and a rounding is formed at a boundary where the surface of the convex portion turns to the concave portion.