JP2012230879A - Switch mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a switch mechanism and a switch, which are used in an operation section and the like of a small portable electronic apparatus and operate by a depression operation, can obtain a large operation stroke irrespective of a thin structure and can obtain a stable contact state.SOLUTION: The switch mechanism includes a base member 10 having an opening 12 where a center electrode 11 is formed and an outer electrode 13 positioned on an outer side of the center electrode 11; and a contact piece 30 which can elastically be deformed. The center electrode 11 is formed in a range where it continues from a side wall 14 of the opening 12 to a periphery of the opening 12. The contact piece 30 and the center electrode 11 are alienated, and the contact piece 30 is brought into contact with the outer electrode to place the contact piece 30 on the base member 10. Thus, the large stroke and the stable contact state can be obtained with the thin structure.

Description

  The present invention relates to a switch mechanism including an elastically deformable contact and a base member having a central electrode and an outer electrode, and a push switch incorporated in a small electronic device using the switch mechanism.

  A thin switch is disposed in an operation unit of a small portable electronic device such as a cellular phone as the size is reduced. For example, as a conventional example, there is a switch disclosed in Japanese Patent Laid-Open No. 2008-234889. As shown in FIG. 7, a central conductive pattern 102 and an outer conductive pattern 103 are formed on the substrate 101, and a plate-shaped contact spring 201 having a convex shape on the upper side contacts the outer conductive pattern 103 on the outer periphery. The plate-like top 202 is spaced from the central conductive pattern 102 and placed on the substrate 101, the adhesive sheet 301 is pasted thereon, and the contact spring 201 is fixed on the substrate 101 to form the switch 001. When the top portion 202 of the contact spring 201 is pressed by the pressing member 401, the contact spring 201 is repelled, and the top portion of the contact spring 201 contacts the central conductive pattern 102, thereby the central conductive pattern 102 and the outer conductive pattern. 103 is short-circuited and the switch is turned on.

  Further, in the conventional example shown in FIG. 7, the pressing member 401 that presses the top 202 of the contact spring 201 is formed of an elastic rubber so as to increase the operation stroke of the switch 001, whereby the operation of the contact spring 201 is performed. The operation stroke of the switch 001 is increased from the stroke and the compression stroke of the pressing member 401.

JP 2008-234889 A

  However, in such a conventional switch 001, when the top portion 202 of the contact spring 201 is pressed, the contact spring 201 is reversed and the top portion 202 is brought into contact with the central conductive pattern 102 which is almost directly below, thereby causing the outer conductive pattern to be in contact. 103 and the central conductive pattern 102 are short-circuited via the contact spring 201 and the switch 001 is turned on, so that the operation stroke is determined by the separation distance between the top 202 of the contact spring 201 and the central conductive pattern 102. When increasing the stroke, it is necessary to increase the distance between the top portion 202 of the contact spring 201 and the central electrode pattern 102. Therefore, the contact spring 201 having a large height in the operation direction is required, and the height of the entire switch is increased. Portable electrical devices that are required to be thinner and thinner The use of it is conceivable that becomes difficult.

  Further, when the operation stroke of the switch 001 is increased without changing the stroke of the contact spring 201 in the operation direction, the elasticity of rubber or the like is superimposed on the contact spring 201 as in the conventional example shown in FIG. It is necessary to increase the operation stroke of the switch 001 by disposing the pressing member 401 and adding the elastic deformation amount of the pressing member 401 to the stroke of the contact spring 201. Even in this case, a separate part such as a pressing member 401 made of rubber or the like is necessary, and the pressing member 401 such as rubber is placed on the contact spring 201 so that the height of the operation direction of the switch 001 is large. There was a problem of becoming.

  Accordingly, in view of the above-mentioned problems, the present invention can increase the operation stroke without increasing the contact spring and without adding a separate part, and can be used for a small, particularly thin portable electric device. It is intended to provide a mechanism or switch.

  In order to solve this conventional problem, a switch mechanism according to claim 1 includes: a base member having a center electrode and an outer electrode positioned on the outside away from the center electrode; and an elastically deformable contact. An opening is formed in the center electrode, the contact is placed on the base member, the contact and the outer electrode are always in contact, and in an initial state, the contact and the center electrode are separated from each other, The contactor and the central electrode are in contact with each other in an operation state in which a pressing force is applied to the contactor, and a part of the contactor enters the opening.

  The switch mechanism according to claim 2 is characterized in that, in addition to the configuration of claim 1, the central electrode is formed in a range extending continuously from the side wall of the opening to the periphery of the opening. is there.

  According to a third aspect of the present invention, in addition to the configuration of the first or second aspect, the base member is a flat plate, and the opening is a through-hole penetrating the base member. It is.

  According to a fourth aspect of the present invention, in addition to the structure of the first, second, or third aspect, the contact is an elastic body obtained by processing a metal plate into a dome shape, and an outer peripheral edge contacts the outer electrode. And it is mounted on the said base member, It is characterized by the above-mentioned.

  According to a fifth aspect of the present invention, in addition to the configuration of the first, second, third or fourth aspect, the center electrode is formed by printing.

  7. The switch according to claim 6, wherein a base member having a center electrode and an outer electrode located outside the center electrode and an outer electrode, an elastically deformable contact, and an adhesive member that overlaps the contact and is bonded to the base member. The base member is formed with a central electrode output portion extending from the central electrode and an outer electrode output portion extending from the outer electrode, and the central electrode has an opening. The contactor is placed on the base member, and the contactor and the outer electrode are always in contact with each other, and in an initial state, the contactor and the central electrode are separated from each other, and in the operation state in which a pressing force is applied to the contactor The contact and the central electrode are in contact with each other, and a part of the contact enters the opening.

  According to a seventh aspect of the present invention, in addition to the configuration of the sixth aspect, the center electrode is formed in a range extending continuously from the side wall of the opening to the periphery of the opening. .

  In the switch according to claim 8, in addition to the configuration of claim 6 or 7, the base member is a flat plate, the opening is a through-hole penetrating the base member, and the central electrode is the through-hole. It is formed in a range from the side wall of the hole to the periphery of the opening on the surface that is a plane on which the contact is placed and from the side wall of the through hole to the periphery of the opening on the back surface that is the opposite surface of the surface. It is characterized by that.

  According to a ninth aspect of the present invention, in addition to the configuration of the sixth, seventh, or eighth aspect, the outer electrode output portion includes a through-hole formed in the base member with an extended portion from the outer electrode. The center electrode output portion is formed on the back surface and extends from the center electrode.

  According to a tenth aspect of the present invention, in addition to the configuration of the sixth, seventh, eighth, or ninth aspect, at least one of the output portion for the central electrode and the output portion for the outer electrode is provided in the thickness direction of the base member. It is formed on the side wall.

  The switch mechanism according to claim 11 is characterized in that, in addition to the configuration of claim 6, 7, 8, 9 or claim 10, a part of the outer electrode is formed wider than the other part. Is.

  A switch mechanism according to a twelfth aspect of the present invention is the switch mechanism according to the sixth, seventh, eighth, ninth, tenth or eleventh aspect, wherein the contactor is formed by processing a metal plate into a disc-shaped disc spring, A peripheral edge portion is connected to the outer electrode and is placed on the base member.

  The switch mechanism according to a thirteenth aspect is characterized in that, in addition to the configuration of the sixth, seventh, eighth, ninth, tenth, eleventh or twelfth aspect, the central electrode is formed by printing. .

  In addition to the structure of Claim 8, 9, 10, 11, 12, or Claim 13, the switch mechanism according to Claim 14 is for preventing the flat plate from warping at least one of the front surface or the back surface. And a warp preventing portion formed by the same material and the same processing method as the central electrode or the outer electrode.

  According to the invention of claim 1, since the opening is formed in the center electrode, when the elastically deformable contact contacts the center electrode by the pressing force, a part of the elastically deformed portion of the contact is the opening. Even after the contact contacts the center electrode, the contact is further elastically deformed by applying a pressing force, and can be elastically deformed in the depth direction of the opening. The amount of deformation of the contact can be increased, and the operation stroke in the switch mechanism can be increased.

  According to the second aspect of the present invention, since the central electrode is also formed at the corner portion formed by the side wall of the opening and the surface having the outer electrode of the base member, the elastically deformable contact is pressed by the pressing force. When the contact is made, the contact is brought into contact with the central electrode at the aforementioned corner, so that a stable contact state can be maintained.

  According to the invention of claim 3, since the base member is a flat plate and the opening is a through hole, it is possible to increase the amount of deformation by which the contact is elastically deformed in the depth direction of the opening. Since the member and the contact are overlapped, the mechanism itself can be made thin.

  According to the invention of claim 4, since the contact is a dome-shaped elastic body, it repels in the process of elastic deformation by pressing, a feeling of clicking is obtained, and a better operational feeling can be obtained. When the dome-shaped curved portion enters the opening by reversal, a larger operation stroke can be obtained.

  According to the invention of claim 5, since the central electrode is formed by printing, the electrode can be easily formed, and the base member can be formed with a small thickness, so that the switch mechanism can be thinned. .

  According to the sixth aspect of the present invention, since the opening is formed in the central electrode, when the elastically deformable contact is brought into contact with the central electrode by the pressing force, a part of the elastically deformed portion of the contact is opened. Even after the contact contacts the center electrode, the contact is further elastically deformed by applying a pressing force, and can be elastically deformed in the depth direction of the opening. The amount of deformation of the contact can be increased, and the operation stroke in the switch mechanism can be increased. Further, by stacking the sheet on the contact and adhering it to the base member, the positional relationship between the opening and the contact can be stabilized, and the contact in the switch can be stabilized.

  According to the seventh aspect of the present invention, since the central electrode is also formed at the corner portion formed by the side wall of the opening and the surface having the outer electrode of the base member, the elastically deformable contact is pressed by the pressing force. When the contact is made, the contact is brought into contact with the central electrode at the aforementioned corner, so that a stable contact state can be maintained.

  According to the eighth aspect of the present invention, since the base member is a flat plate and the opening is a through hole, it is possible to increase the amount of deformation by which the contact is elastically deformed in the direction of the opening. Since the contacts are overlapped with each other, the switch itself can be made thin. The central electrode is formed in the range from the side wall of the through hole to the periphery of the opening on the surface, which is a plane on which the contact is placed, and from the side wall of the through hole to the periphery of the opening on the back surface, which is the opposite surface of the surface. Therefore, the center electrode output portion can be formed on the back surface of the base member, and the switch can be more easily mounted on the electric circuit board or the like.

  According to the ninth aspect of the present invention, the output portion for the outer electrode is formed on the back surface of the base member through the through hole formed in the base member, so that the output portion for the outer electrode serves as a base. It can be formed on the back surface of the member, and the switch can be more easily mounted on an electric circuit board or the like.

  According to the invention of claim 10, since at least one of the central electrode output portion and the outer electrode output portion is formed on the side wall in the thickness direction of the base member, the switch is mounted on the electric circuit board by soldering. A solder fillet is formed between the central electrode output portion or the outer electrode output portion formed on the side wall and the mounting pattern such as the electric circuit board, so that the switch can be mounted more firmly.

  According to the eleventh aspect of the invention, the outer electrode is formed such that a part of the outer electrode is wider than the other part. Can be prevented from becoming a non-contact state.

  According to the invention of claim 12, since the contact is a dome-shaped elastic body, it repels in the process of elastic deformation by pressing, a click feeling can be obtained, and a better operational feeling can be obtained. When the dome-shaped curved portion enters the opening by reversal, a larger operation stroke can be obtained. Further, even when the sheets are stacked and attached to the base member for positioning, the contact state with the outer electrode can be kept uniform at each contact portion.

  According to the invention of claim 13, since the central electrode is formed by printing, the electrode can be easily formed, and the base member can be formed with a small thickness, so that the switch can be thinned.

  According to the invention of claim 14, since the warp preventing portion is provided on at least one of the front surface and the back surface of the base member, when high temperature heat is applied when the switch is mounted on the electric circuit board by soldering or the like. In this case, it is possible to prevent the base member and the switch itself from being deformed by warping.

  (A) Front perspective view of the switch according to the present invention (b) Front perspective view of the switch according to the present invention with the sheet constituting the switch according to the present invention removed.   The exploded front perspective view of the switch concerning the present invention   (A) Front side perspective view of a base member constituting a switch according to the present invention (b) Back side perspective view of a base member constituting a switch according to the present invention   Sectional drawing in the aa line | wire of Fig.1 (a) in the press operation state of the switch which concerns on this invention   (A) Front side perspective view showing a switch in the second embodiment according to the present invention (b) Front side perspective view when the switch in the second embodiment according to the present invention is mounted on an electric circuit board   (A) Front side perspective view of a base member constituting a switch according to the second embodiment of the present invention (b) Rear side perspective view of a base member constituting a switch according to the second embodiment of the present invention   Exploded perspective view of a conventional switch

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. 1 to 5 show an embodiment of the present invention. FIG. 1 is a front view of a switch according to the present invention, FIG. 2 is an exploded front perspective view of the switch according to the present invention, and FIG. ) Is a front side perspective view of the base member constituting the switch according to the present invention, (b) is a rear side perspective view of the base member constituting the switch according to the present invention, and FIG. 4 is a pressing operation state of the switch according to the present invention. 1 is a cross-sectional view taken along line AA of FIG. 1, FIG. 5A is a front perspective view showing a switch in the second embodiment of the present invention, and FIG. 5B is a second embodiment of the present invention. It is a surface side perspective view when the switch in is mounted on an electric circuit board. The switch 01 includes a base member 10, a contact 30, and a sheet 40.

  The base member 10 is a substrate that is a flat plate, and an opening 12 that is a circular through hole is provided in the center of the base member 10. A side wall 14 of the opening 12, that is, an inner peripheral wall of the through hole, and a side wall 14. A conductive central electrode 11 is formed in a range extending continuously from around the opening 12 on both sides of the flat plate. In this embodiment, the base member 10 is a laminated board made of a glass epoxy material, and the central electrode 11 and the outer electrode 13 to be described later are formed by subjecting copper foil to conductive plating by etching or the like. It has been done. Further, the central electrode 11 is formed in a range that is concentric with the opening 17 on the front surface 17 and the back surface 18 of the base member 10 continuously from the side wall 14 of the opening 12. The surface 17 indicates a surface on which the contact 30 is placed as described later, and the back surface 18 is an opposite surface of the surface 17. Further, the outer electrode 13 is formed in a substantially concentric shape outside the central electrode 11 on the surface 17, and a part of the outer electrode 13 forms an outer electrode contact portion 20 that is formed wider than other portions.

  In addition, an extended portion having a central electrode output portion 15 formed widely at the end portion is formed continuously from the central electrode 11 formed on the back surface 18. The outer electrode 13 extends to the through hole 21 which is a through hole formed in the base member 10, further extends to the back surface 18 through the through hole 21, and a wide outer electrode output portion 16 is formed at the end. Yes.

  The contact 30 is formed by forming a thin metal plate made of a conductive metal into a dome shape, and a metal plating for obtaining high conductivity is applied to the surface in order to reduce the contact resistance.

  The sheet 40 is formed by forming a film-like material made of a polymer material such as PI (polyimide) smaller than the base member 10 in a substantially similar shape, and is attached to the surface 17 of the base member 10 on one surface. The adhesive or adhesive tape is applied or affixed.

  Next, assembly of the switch 01 using the above components and mounting on the electric circuit board 50 will be described. First, the contact 30 is placed on the base member 10. At this time, the apex 32 at the substantially center of the contact 30 curved in a dome shape is separated from the center electrode 11 so that it is almost directly above the center of the opening 12 of the center electrode 11 of the base member 10. The contact 30 is placed on the base member 10 with the edge 31 of the contact 30 in contact with the outer electrode 13.

  Next, in this state, the surface of the sheet 40 on which the adhesive or adhesive tape is applied or pasted is opposed to the surface 17 of the base member 10, and is pasted on the base member 10 so as to overlap the contact 30. At this time, the case where the sheet 40 and the contact 30 are adhered to each other and the case where the adhesive or the adhesive tape is partially removed and the sheet 40 and the contact 30 are not adhered can be appropriately selected. In this way, the switch 01 is completed and mounted on the electric circuit board 50 or the like.

  The switch 01 is mounted on the electric circuit board 50 or the like as follows. As shown in the figure, in the first embodiment, the center electrode output portion 15 and the outer electrode output portion 16 are formed on the back surface 18 of the base member 10, and the center electrode output formed on the electric circuit board 50 is formed. After the central electrode output unit 15 and the outer electrode output unit 16 are mounted on the electric circuit pattern corresponding to the unit 15 and the outer electrode output unit 16, the switch 01 is connected to the electric circuit board 50 by soldering. Implementation is complete.

  As shown in FIGS. 5 and 6, in the second embodiment, the four corners 22 of the base member 10 are notched in a concave shape, and the side walls 23 at the corners 22, that is, the flat base member. And the periphery of the concave cutouts on the front and back surfaces are the central electrode output part and the outer electrode output part, and the central electrode output part and the outer electrode use part. As shown in FIG. 6, the output unit is placed on the corresponding electric circuit pattern of the electric circuit board and soldered, whereby the mounting of the switch on the electric circuit board is completed. At this time, since the output portion for the central electrode and the output portion for the outer electrode are provided on the concave side wall 23 of the base member, the central electrode output portion provided on the concave side wall 23 when soldering during mounting. Alternatively, the solder fillet 60 is formed between the output portion for the outer electrode and the corresponding electric circuit pattern, and thus, a strong mounting is achieved.

  The switch 01 thus completed and mounted is operated as follows. First, when a pressing force is applied to the dome-shaped top 32 of the contact 30 from the outside through the sheet 40, the contact 30 is elastically deformed, and the top 32 approaches the opening 12 of the base member 10. When the dome-shaped curved portion is inverted after a certain elastic deformation, or when the dome-shaped curved portion is further elastically deformed after being inverted, a part of the curved portion of the contact 30 comes into contact with the central electrode 11 formed in the opening 12. It will be. At this time, since the central electrode 11 continuously extends from the side wall 14 of the opening 12 to the periphery of the opening 12 on the surface 17, the contact 30 is connected to the central electrode 11 at the corner 22 formed by the side wall 14 and the surface 17. As a result, the outer electrode 13 and the central electrode 11 that are in contact with the edge 31 of the contactor 30 are short-circuited via the contactor 30, and the switch 01 is turned on as shown in FIG. Become.

  In this ON state, since the dome-shaped curved portion of the contact 30 has already been reversed as described above, the surface on the opening side of the dome-shaped top portion 32 curved toward the opening 12 by the reversal is as follows. It will be located in the direction of the back surface 18 of the base member 10 which is below the height of the front surface 17 of the base member 10. Therefore, the moving distance from the initial state of the top 32 of the contact 30 is shown in FIG. 4 as compared with the case where the central conductive pattern is formed on the surface without providing an opening as in the conventional switch mechanism. As described above, it is possible to obtain a larger amount of movement of the distance A between the surface of the top portion 32 in the switch ON state and the surface of the base member 10. That is, the operation stroke until the switch is turned on can be increased by the distance A as compared with the conventional stroke having no opening.

  If the contact 30 is in a range that can be elastically deformed without being plastically deformed even after it is turned on, the top 12 is further pushed by continuing to press the top 32 of the contact 30 due to the presence of the opening 12. It is possible to move the base member 10 in the downward direction toward the bottom. As a result, if the moving distance of the top 32 after the ON state is α, the operating stroke can be increased by a distance of A + α in combination with the distance B as compared with the conventional switch having no opening. It is possible to obtain a better operational feeling.

  As described above, when the switch 01 is turned on, a part of the contact 30 comes into contact with the corner portion 22 formed by the side wall 14 and the surface 17 of the opening 12 forming the central electrode 11. Therefore, a more stable contact state can be obtained.

  As described above, the switch 01 according to the present invention is easy to form the central electrode 11 in the opening portion 12 despite the thin switch constituted only by the base member 10 such as a substrate, the dome-shaped contact 30 and the sheet 40. By adopting a simple structure, it is possible to obtain a larger operation stroke and obtain a stable contact state.

  Further, by making the opening 12 forming the central electrode 11 into a through hole, the central electrode output portion 15 can be formed on either the front surface 17 or the back surface 18 of the base member. By forming a through hole 21 as a through hole in a substrate or the like as the base member 10, it is possible to continuously extend from the outer electrode 13 and to form the output portion 16 for the outer electrode on the back surface 18 through the through hole. As a result, it is possible to give a greater degree of freedom to the method of mounting the switch on the electric circuit board or the like that depends on the positions of the central electrode output portion 15 and the outer electrode output portion 16.

  Furthermore, since there is a degree of freedom in the arrangement of the central electrode output portion 15 and the outer electrode output portion 16, it is easy to form the warp prevention portion 19 for preventing the warpage of the base member 10 or the like. This makes it possible to take efficient warp prevention measures.

  In addition, the contact used for this switch is not limited to a dome shape, but can be used for the switch mechanism and the switch according to the present invention as long as a curved portion is formed and elastically deformed, and the material is only a metal plate. In addition, the switch mechanism and the switch according to the present invention can be used as long as they have elasticity such as rubber, have conductivity, or have been subjected to conductive treatment. In addition, the base member is not only a substrate, but an opening is formed, and a conductive central electrode, an outer electrode, a central electrode output part, an outer electrode output part, and a conductive part that continues these can be formed. The switch mechanism and the switch according to the present invention can be used.

01 switch 10 base member 11 central electrode 12 opening 13 outer electrode 14 sidewall 15 central electrode output portion 16 outer electrode output portion 17 surface 18 back surface 19 warpage prevention portion 20 outer electrode contact portion 21 through hole 22 corner portion 23 concave sidewall 30 Contact 31 Edge 32 Top 40 Sheet 50 Electrical Circuit Board 60 Solder Fillet 001 Switch 101 Substrate 102 Central Conductive Pattern 103 Outer Conductive Pattern 201 Contact Spring 202 Top 301 Adhesive Sheet 401 Pressing Member

Claims (14)

  A base member having a central electrode and an outer electrode positioned on the outer side away from the central electrode; and an elastically deformable contact, wherein the central electrode has an opening, and the contact is formed by the base The contactor and the outer electrode are always in contact with each other, and the contactor and the central electrode are separated from each other in an initial state, and the contactor and the central electrode are in an operation state in which a pressing force is applied to the contactor. Is a switch mechanism, wherein a part of the contact enters the opening.   The switch mechanism according to claim 1, wherein the central electrode is formed in a range extending continuously from a side wall of the opening to the periphery of the opening.   The switch mechanism according to claim 1, wherein the base member is a flat plate, and the opening is a through-hole penetrating the base member.   The said contactor is an elastic body which processed the metal plate in the dome shape, and an outer peripheral edge part contacts the said outer side electrode, and is mounted in the said base member, The Claim 1, 2 or 3 characterized by the above-mentioned. Switch mechanism.   The switch mechanism according to claim 1, wherein the center electrode is formed by printing.   A base member having a central electrode and an outer electrode located on the outer side away from the central electrode, a contact that is elastically deformable, and a sheet that overlaps the contact and is bonded to the base member. The member has a central electrode output portion extending from the central electrode and an outer electrode output portion extending from the outer electrode, an opening is formed in the central electrode, and the contact is the base member The contactor and the outer electrode are always in contact with each other, and in an initial state, the contactor and the central electrode are separated from each other. In an operation state in which a pressing force is applied to the contactor, the contactor and the central electrode are A switch that contacts and a part of the contact enters the opening.   The switch according to claim 6, wherein the central electrode is formed in a range extending continuously from the side wall of the opening to the periphery of the opening.   The base member is a flat plate, the opening is a through-hole penetrating the base member, and the central electrode is a flat surface on which the contact is placed from a side wall of the through-hole. 8. The switch according to claim 6, wherein the switch is formed in a range from a periphery and a periphery of the opening on a back surface opposite to the front surface from a side wall of the through hole. 9. The output portion for the outer electrode is formed on the back surface through a through hole formed in the base member, and the output portion for the center electrode extends from the center electrode and extends on the back surface. The switch according to claim 6, 7 or 8, wherein the switch is formed as follows. The switch according to claim 6, 7, 8, or 9, wherein at least one of the central electrode output portion and the outer electrode output portion is formed on a side wall in a thickness direction of the base member.   The switch according to claim 6, 7, 8, 9 or 10, wherein a part of the outer electrode is formed wider than the other part.   The contactor is formed by processing a metal plate into a dish-shaped disc spring, and an outer peripheral edge portion is placed on the base member in contact with the outer electrode. , 9, 10 or 11 switch.   The switch mechanism according to claim 6, 7, 8, 9, 10, 11 or 12, wherein the central electrode is formed by printing.   In order to prevent the flat plate from warping at least one of the front surface and the back surface, the warp prevention portion is formed of the same material and the same processing method as the central electrode or the outer electrode. The switch according to claim 8, 9, 10, 11, 12 or 13.

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