JP2001266975A - Heat welding anisotropic conductive elastic connector and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat welding anisotropic conductive elastic connector and its manufacturing method in which a unit body fixed mounting by a reflow furnace is possible on a printed circuit board and in which fixing and connection with the printed circuit board can be carried out with high reliability. SOLUTION: In the anisotropic conductive elastic connector consisted of a rubber part 2 and a conductive part 1 and having an electroconductivity in a compressed top and bottom direction, heat weldable powders 2 which are heat weldable with a metal foil of printed circuit board is made to be exposed and formed on at least one single side of compressed top and bottom face. After this connector is heat welded on the metal foil 6 of the printed board 4, it is pressure contacted and mounted on an electrode circuit part 8 of the counterpart printed board 7 (or, electronic parts), and an electric conduction is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used for connection between printed circuit boards and connection between printed circuit boards and electronic components, and particularly for mounting applications in a reflow furnace widely used for automatic mounting of electronic components. The present invention relates to a suitable heat-fused anisotropic conductive elastic connector and a method for manufacturing the same.

[0002]

2. Description of the Related Art An example of mounting an elastic connector used for connecting an indium-tin oxide (ITO) terminal, which is a transparent electrode of a liquid crystal display (LCD), to a printed circuit board will be described. Printed circuit board (PC) on which other electronic components are mounted in the reflow process in advance
B) and an LCD mounted on a resin or metal frame also serving as a connector holder function is prepared, and the LCD in which the elastic connector is accommodated in the connector holder is mounted at a predetermined position on the printed circuit board, whereby mounting is performed. .

Further, an elastic connector used for connection between printed circuit boards includes an FPC and a PCB.
Is an example. Paste an elastic connector with a surface adhesive treatment to temporarily fix it at a predetermined mounting position on the connection terminal of the PCB on which other electronic components have been mounted in the reflow process in advance, and then withstand pressure contact with the elastic connector The FPC, which is backed by a resin plate or the like, is positioned at a predetermined position and press-contacted to perform mounting.

[0004]

However, in the connection between the LCD and the printed circuit board, the elastic connector must be manually held in the connector holder, and the connector holder has a construction that exceeds the volume of the elastic connector. Since the space is provided, the elastic connector is easily inserted obliquely, and the contact resistance with the PCB to be connected thereafter is easily increased.

Further, in the above-mentioned elastic connector used for connection between printed circuit boards, the elastic connector whose surface has been subjected to an adhesive treatment must be pasted on the connection terminal of the PCB by hand. Workers need skill on board terminals whose positions must be managed in mm units. Further, there is a problem that even if a worker has a high level of skill, since the work is performed by a human hand, the sticking position is inevitably shifted. In addition, when the adhesive adheres to the conductive portion of the elastic connector, there is a problem that poor conduction occurs.

[0006] Furthermore, all components mounted on a printed circuit board are basically automatically mounted, and it is strongly desired that an elastic connector, which is premised on manual mounting, can be mounted automatically. Was rare.

The present invention solves the above-mentioned problem by allowing a single unit to be fixedly mounted on a printed circuit board by a reflow furnace (automatic mounting), and enables a highly reliable fixing and connection with the printed circuit board. An object of the present invention is to provide a wearable anisotropic conductive elastic connector and a method for manufacturing the same.

[0008]

Means for Solving the Problems In order to achieve the above object, a heat-fusible anisotropic conductive elastic connector according to the present invention is characterized in that, in an anisotropic conductive elastic connector having electrical conductivity in a compression vertical direction, a compression-bonded anisotropic conductive elastic connector is provided. A heat-sealing powder that can be heat-sealed to the metal foil of the printed circuit board is formed on at least one surface of the lower surface.

In the present invention, it is preferable that the heat sealing powder is electrically connected to a main conductor of the anisotropic conductive elastic connector.

[0010] In the present invention, the anisotropic conductive elastic connector has a magnetic thin wire oriented in a thickness direction as a main conductor, and one end of the magnetic thin wire is exposed from an insulating elastic portion. It is preferable that the other one be electrically connected to the heat-sealing powder exposed and fixed to the surface layer of the connector.

Further, in the present invention, the anisotropic conductive elastic connector is formed by laminating and arranging magnetic powder as a main conductor in the thickness direction, and the magnetic powder is exposed and fixed to at least one surface of the connector. It is preferable to make electrical connection with the heat sealing powder.

In the present invention, the heat-sealing powder is preferably a solder-coated powder having a solder powder or a magnetic powder as a core.

In the present invention, the solder or the solder coat is preferably at least one selected from Sn—Pb, Sn—Zn and Sn—Ag.

In the present invention, the average particle diameter of the heat-sealing powder is preferably in the range of 0.1 mm to 1.0 mm.

Further, in the present invention, it is preferable that the exposed area of the heat sealing powder is not more than half of the total surface area.

Next, in a first method of manufacturing a heat-fused anisotropic conductive elastic connector according to the present invention, magnetic lines of force are localized on a board surface in a mold having a molding space for obtaining a predetermined shape. And a concave portion for fixing the heat-sealing powder independently of each other. After fixing the heat-sealing powder to the predetermined recess, an unvulcanized elastomer mixed with a magnetic material serving as a main conductor is used. The method is characterized in that the magnetic material is injected into a mold, the magnetic material is localized by a magnetic field, and the heat-sealing powder is exposed and formed on at least one of the surface layers of the elastomer by curing of the elastomer by heating.

Next, a second method of manufacturing a heat-fused anisotropically conductive elastic connector according to the present invention comprises the steps of: providing a mold having a molding space for obtaining a predetermined shape; And a concave portion for fixing the heat-sealing powder, and after fixing the heat-sealing powder to the predetermined recess, an unvulcanized elastomer mixed with a magnetic material serving as a main conductor is removed. The magnetic material is injected into a mold, the magnetic material is localized by a magnetic field, and the heat-sealing powder is exposed and formed on at least one of the surface layers of the elastomer by curing of the elastomer by heating. Are electrically connected.

[0018]

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an anisotropically conductive elastic connector having electrical conductivity in the vertical direction of compression, wherein heat-sealing powder is exposed and fixed to at least one of the upper and lower surfaces of the compression. Since the powder has a function of melting and bonding on the metal foil of the printed circuit board, it can be fixedly mounted by a reflow furnace.

In the present invention, it is possible to electrically connect the main conductor and the heat-sealing powder, and to fix the electrode portion on the printed circuit side and the conductive portion of the connector by a reflow furnace.

Further, the main conductor is a magnetic thin wire, one end of the magnetic thin wire is exposed from the insulating elastic portion, and the other end is exposed and fixed to the surface of the connector.
An electrical connection can be made with the heat sealing powder.

The main conductor is a magnetic powder laminated and arranged in the thickness direction of the connector, and can be electrically connected to at least the heat-sealing powder exposed on one side of the connector.

Further, according to the manufacturing method of the present invention, in a mold having a molding space for obtaining a desired shape, a portion for localizing the lines of magnetic force on the board surface and a concave portion for fixing the heat fusion powder are respectively provided. After independently fixing the heat-sealing powder in a predetermined recess, an unvulcanized elastomer mixed with a magnetic material serving as a main conductor is injected into a mold, and the magnetic material is pressed by a magnetic field. This is a manufacturing method in which the heat-sealing powder is exposed to at least one of the surface layers of the elastomer by localizing and curing the elastomer by heating.

The second manufacturing method of the present invention relates to a mold having a molding space for obtaining a desired shape, a portion for localizing lines of magnetic force at the same portion on the board surface, and a heat-sealing powder. It has a concave portion for fixing, after fixing the heat-sealing powder in a predetermined concave portion, an unvulcanized elastomer mixed with a magnetic material serving as a main conductor is poured into a mold, and the magnetic field is applied by a magnetic field. A method for localizing a magnetic material, exposing the heat-bonded powder to at least one of the surface layers of the elastomer by curing the elastomer by heating, and electrically connecting the magnetic material and the heat-bonded powder. .

Next, a description will be given with reference to the drawings. Figure 1 shows the conductive part 1.
And a heat-sealing powder 3 located below the compression upper and lower surfaces. The particle size of the heat sealing powder 3 is 0.1 mm or more
1.0 mm, more preferably 0.3 mm to 0.75 particle size
mm, and is fixedly formed with half or less of the total surface area exposed.

As the material of the heat sealing powder, a solder powder or a solder coat powder having a magnetic powder as a nucleus is used, and as a material of the solder and the solder coat, Sn—Pb, S
It is selected from n-Zn, Sn-Ag, and the like, and the material serving as the core powder of the solder coat powder is selected from nickel, iron, and other magnetic alloys.

An implementation example will be described with reference to FIGS. Heat-fused powder 3 on metal foil 6 of the same material as circuit electrode 5 on printed circuit board 4
Is fixed so as to be positioned, and heat fusion is performed in a reflow furnace while applying pressure so that the fixed position does not shift. The conditions at the time of reflow are as follows when Sn-Pb solder is used for the heat fusion powder 3.
As a guide, the temperature is set to 220 ° C. or more, and the application time after reaching the temperature is set to 5 seconds or more. In the case of Sn—Zn or Sn—Ag solder, the temperature is set to 250 ° C. or more and the application time after reaching the temperature is set to 5 seconds or more.

After the present connector is fused onto the metal foil 6 of the printed circuit board 4, as shown in FIG.
(Or electronic components) by pressure-contact mounting with the electrode circuit section 8 to obtain conduction.

FIG. 4 includes a conductive portion 1, an insulating elastic portion 2, and a heat-sealing powder 3 having an electrical connection to the conductive portion 1. FIGS. 5 and 6 show a mounting example of the present invention. The heat-sealing powder 3 is fixed on the electrode circuit 10 of the printed circuit board 9 so as to be positioned, and heat-sealing is performed in a reflow furnace while the fixing position is not shifted.

After fusing to the electrode circuit 10 on the printed circuit board 9,
As shown in FIG. 6, the mating substrate 11 is pressure-contact mounted to obtain electrical continuity.

FIG. 7 is composed of a magnetic thin wire 12 which is a conductive portion, an insulating elastic portion 2 and a heat sealing powder 3 having an electrical connection to the magnetic thin wire 12. The magnetic wire 12 is oriented in the thickness direction and localized in the plane direction, and the wire diameter is 8 μm diameter (φ) to 45 μm
φ, more preferably 12 μmφ to 25 μmφ, and iron, nickel, stainless steel or the like is used as a material. Solder on the surface in the sense of preserving and stabilizing current carrying performance,
It is plated with tin, silver, gold or the like. Magnetic wire
The length of 12 is not limited, but is preferably 5 mm or less, and more preferably 2 mm or less from the viewpoint of giving stability to the orientation.

The material of the insulating elastic portion 2 is a polymer,
Any material that has sufficient melt fluidity to disperse the magnetic material that is the conductive part at the stage of prepolymer or monomer, and that forms an elastic polymer by polymerization or solidification, is excellent in weather resistance And silicone rubber is preferred because of its low contamination to the housing.

One end of the magnetic thin wire 12 is exposed from the insulating elastic portion, and the other end is electrically connected to the heat-sealing powder 3 which is exposed and fixed to the surface of the connector.

FIG. 8 shows a magnetic powder 13 which is a conductor, an insulating elastic part 2 and a heat-sealing powder 3 having an electrical connection to the magnetic powder 13, and is exposed and fixed to at least one surface of the connector. The fusion powder 3 and the magnetic powder 13 have an electrical connection. The magnetic powder 13 is laminated in the thickness direction and localized in the plane direction, and has a single particle diameter of 5 μmφ to 50 μmφ. As a material, iron, nickel, a magnetic alloy, or the like is used, and the surface is plated with solder, tin, silver, gold, or the like for the purpose of preserving and stabilizing the current-carrying performance.

The shape of the magnetic powder 13 is not particularly limited, and any one of a spherical powder, a scaly powder, and an amorphous powder can be selected. A scaly powder is preferably used.

Next, description will be made with reference to FIG. First, as a configuration of the mold, a mold 16 placed between the electromagnets 14 and 15 is composed of a non-magnetic material portion 17 and a magnetic material 18, and the magnetic material 18 defines a target molding space 19 in upper and lower molds. It is arranged at a position facing and sandwiching. Also, a recess 20 for fixing the heat fusion powder is
And a suction gate 21 for firmly fixing the heat-sealing powder to the die board surface. The opening diameter of the concave portion is equal to or smaller than the diameter of the heat-sealing powder, and the magnetic material 18 and the concave portion 20 for fixing the heat-sealing powder are not located at the same portion on the die board surface and are constant. Is provided. Iron or a nickel-based alloy or the like is used for the magnetic material 18 constituting the mold, and aluminum or a non-magnetic alloy is used for the non-magnetic material 17. As a molding method, mold recess 20
Put the heat-sealing powder in the suction gate 21, fix the heat-sealing powder in the suction gate 21, put a mixture of magnetic thin wire or magnetic powder into a polymer having melt fluidity in the molding space 19, apply a magnetic field, Magnetic fine wires or magnetic powders are arranged along the lines of magnetic force between the upper and lower sides of the magnetic material 18 of the mold. After the arrangement has been made, heating the mold molding space 19 and curing the polymer,
Heat fusion type anisotropic conductive elastic connector can be made.

Next, a description will be given with reference to FIG. First, as a configuration of the mold, a mold 22 placed between the electromagnets 14 and 15 is composed of a non-magnetic material part 23 and a magnetic material 24, and the magnetic material 24 defines a target molding space 25 in upper and lower molds. It is arranged at a position facing and sandwiching. Also, at least one of the upper and lower surfaces of the mold is provided with a recess 26 for fixing the heat-sealing powder at the same position as the magnetic material 24, and the opening diameter of the recess 26 is the same as the diameter of the heat-sealing powder, or It is as follows. As a molding method, heat fusion powder having magnetic powder as core powder is put in the concave portion 26 of the mold, the heat fusion powder is fixed by adsorption by an electromagnet, and a magnetic thin wire or a polymer having melt fluidity is formed in the molding space 25. When the mixture of the magnetic powders is put, the magnetic fine wires or the magnetic powders are arranged between the magnetic materials 24 of the mold along the lines of magnetic force. After the arrangement is completed, the inside of the molding space of the mold is heated and the polymer is cured, and the heat-fusing anisotropic conductive material in which the magnetic fine wire or magnetic powder and the heat-fusing powder are electrically connected An elastic connector is made.

[0037]

The present invention will be described more specifically with reference to the following examples.

Example 1 In the mold shown in FIG. 9, a magnetic material 18 is made of a columnar carbon steel, a non-magnetic material 17 is made of aluminum,
The concave portion 20 for fixing the heat-sealing powder is hemispherical, and the opening diameter is 0.5 mm.
φ, depth 0.5 mm. It had a suction gate 21 communicating with the concave portion, and the molding space 19 was 10 mm square and 1 mm deep.
The columnar carbon steel had a diameter of 0.6 mmφ and was arranged in two rows in the die X direction, with nine lines on one side and at a pitch of 1 mm. The distance between the two rows was 3 mm. The recesses for fixing the heat-sealing powder were located at two opposite corners of the molding space 19.

Next, the material to be charged into the mold will be described. 1 mm on the surface of Sn-Pb solder powder with a particle diameter of 0.5 mm
After performing the silane coupling treatment of wt%, it was placed in the concave portion 20 on the mold surface and fixed by suction. Viscosity 10Pa · s
Thermosetting liquid silicone rubber of 0.02mmφ-1.02mm
The long nickel wire was mixed and dispersed uniformly. The mixing weight part of the nickel wire was 5 wt%. The mixed material was filled in a molding space 19 of a mold, and an electromagnet provided above and below the mold was generated with a magnetic flux density of 0.15 T on one side. 80 ° C by localizing the nickel wire in the plane direction and orienting it in the thickness direction by magnetic force
The product (FIG. 11) was obtained by heat curing.

The obtained product (FIG. 11) has an outer diameter of 10 mm square.
Solder powder 27 in 1mm thick shape at two diagonal parts on one side of product
Exposed nickel wire oriented in the thickness direction
28 is a heat-fused anisotropically conductive elastic connector with electrical conductivity on the upper and lower surfaces of the compression. 31 is a silicone rubber.

FIGS. 12, 13, and 14 show application examples of other product shapes.
Is shown. In FIG. 13, reference numeral 32 denotes silicone rubber.

(Embodiment 2) In the mold shown in FIG. 10, the magnetic material 24 is cylindrical carbon steel, the non-magnetic material 23 is aluminum,
The concave portion 26 for fixing the heat sealing powder is hemispherical, and the opening diameter is 0.75 mm.
φ, depth 0.75 mm. Molding space 25 is 10mm square, depth
It is composed of 1.2 mm. The columnar carbon steel was arranged at four points in a square of 5 mm square at the center of the mold with a diameter of 0.6 mmφ. Further, the concave portion 26 for fixing the heat fusion powder was located at the tip of the carbon steel.

Next, the material to be charged into the mold will be described. Nickel powder nucleus with particle size 0.75mmφ
After subjecting the surface of the n-Zn solder powder to silane coupling treatment of 1 wt%, the solder powder is placed in the concave portion 26 on the surface of the mold, and the electromagnet installed under the mold generates a magnetic flux density of 0.15 T. Let it. Solder powder having nickel powder as a core was fixed in the recess by magnetic force. A thermosetting liquid silicone rubber having a viscosity of 13 Pa · s and a nickel powder having an average particle size of 0.02 mmφ were mixed and uniformly dispersed. Nickel powder mixed weight is 40W
t%.

The molding material is filled in a molding space 25 of a mold,
Like the electromagnet on the lower side of the mold to which a magnetic force has already been applied, the electromagnet installed on the upper side of the mold also generated a magnetic flux density of 0.15T. Nickel powder is localized in the plane direction by magnetic force, laminated in the thickness direction, and cured by heating at 80 ° C (Fig.
15) got.

The obtained product (FIG. 15) has an outer diameter of 10 mm square.
A thermocompression bonding type in which a solder powder 30 having a nickel powder as a nucleus is exposed at a center of 5 mm on one side of a product in a 1.2 mm thick shape and a nickel powder 29 is laminated in a thickness direction from the solder powder. It was an elastic connector.

Examples 16 and 17 are shown as application examples of other product shapes.

[0047]

As described above, according to the present invention,
In the anisotropic conductive elastic connector having electrical conductivity in the compression vertical direction, by exposing and fixing the heat-sealing powder on at least one side of the compression upper and lower surfaces, the heat-sealing powder is printed on the metal foil of the printed circuit board. Because of the heat fusion, it can be fixedly mounted in a reflow furnace, and can provide a heat fusion type anisotropic conductive elastic connector capable of reliably connecting to a printed circuit.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a heat fusion type anisotropically conductive elastic connector according to one embodiment of the present invention.

FIG. 2 is a sectional view showing a mounting example using the elastic connector of FIG. 1;

FIG. 3 is a sectional view showing another example of mounting using the elastic connector of FIG. 1;

FIG. 4 is a cross-sectional view showing a heat-fused anisotropic conductive elastic connector according to another embodiment of the present invention.

FIG. 5 is a sectional view showing a mounting example using the elastic connector of FIG. 4;

FIG. 6 is a sectional view showing another example of mounting using the elastic connector of FIG. 4;

FIG. 7 is a sectional view showing a heat-fused anisotropic conductive elastic connector according to another embodiment of the present invention.

FIG. 8 is a cross-sectional view showing a heat-fused anisotropically conductive elastic connector according to another embodiment of the present invention.

FIG. 9 is a cross-sectional view showing a mold used for manufacturing a heat-fused anisotropically conductive elastic connector according to one embodiment of the present invention.

FIG. 10 is a sectional view showing a mold used for manufacturing a heat-fused anisotropically conductive elastic connector according to another embodiment of the present invention.

FIG. 11 is a plan view (top) and a cross-sectional view (bottom) of a heat-fused anisotropic conductive elastic connector obtained in one embodiment of the present invention.

FIG. 12 is a plan view (top) and a cross-sectional view (bottom) of a heat-fused anisotropically conductive elastic connector obtained in another embodiment of the present invention.

FIG. 13 is a plan view (top) and a cross-sectional view (bottom) of a heat-fused anisotropically conductive elastic connector obtained in another embodiment of the present invention.

FIG. 14 is a plan view (top) and a cross-sectional view (bottom) of a heat-fused anisotropic conductive elastic connector obtained in another embodiment of the present invention.

FIG. 15 is a plan view (top) and a cross-sectional view (bottom) of a heat-fused anisotropically conductive elastic connector obtained in another embodiment of the present invention.

FIG. 16 is a plan view (top) and a cross-sectional view (bottom) of a heat-fused anisotropically conductive elastic connector obtained in another embodiment of the present invention.

FIG. 17 is a plan view (top) and a sectional view (bottom) of a heat-fused anisotropically conductive elastic connector obtained in another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Conductive part 2 Insulating elastic body 3 Thermal fusion powder 4,7,9,11 Printed circuit board 5,8,10 Circuit electrode 6 Metal foil 12 Magnetic fine wire 13 Magnetic powder 14,15 Electromagnet 16,22 Die 17,23 Non-magnetic material part 18, 24 Magnetic material part 19, 25 Mold space 20, 26 Mold concave part 21 Mold suction gate 27 Solder powder 28 Nickel wire 29 Nickel powder 30 Solder powder with nickel powder as nucleus

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H05K 1/14 H05K 3/36 Z 3/32 H01R 9/09 C 3/36 23/68 303E F-term ( (Reference) 5E023 AA05 AA16 AA18 BB22 BB29 CC02 CC26 DD26 EE18 FF01 HH01 HH08 HH18 HH28 5E051 CA03 CA04 5E077 BB24 BB31 BB37 CC02 CC22 CC26 DD01 JJ05 JJ11 5E319 AC01 BB16 BB20 CC02 CD02 CD03 CD04

Claims (10)

[Claims] 1. An anisotropic conductive elastic connector having electrical conductivity in the vertical direction of compression, wherein at least one of the upper and lower surfaces of the compression is formed by exposing heat-sealing powder capable of heat-sealing with a metal foil of a printed circuit board. A heat-fused anisotropically conductive elastic connector, characterized in that: 2. The heat-fusible anisotropically conductive elastic connector according to claim 1, wherein the heat-fusible powder is electrically connected to a main conductor of the anisotropically conductive elastic connector. 3. An anisotropic conductive elastic connector, wherein a magnetic thin wire is oriented as a main conductor in a thickness direction, and one end of the magnetic thin wire is exposed from an insulating elastic portion. 3. The heat-fusible anisotropic conductive elastic connector according to claim 2, wherein the other one is electrically connected to the heat-sealing powder exposed and fixed to the surface layer of the connector. 4. An anisotropic conductive elastic connector in which magnetic powder is laminated and arranged in a thickness direction as a main conductor, and said magnetic powder is exposed and fixed to at least one surface of the connector. The heat-fusible anisotropically conductive elastic connector according to claim 2, which is electrically connected to the heat-sealing anisotropic conductive elastic connector. 5. The heat-fusable anisotropically conductive elastic connector according to claim 1, wherein the heat-fusion powder is a solder-coated powder having a solder powder or a magnetic powder as a core. 6. The method according to claim 1, wherein the solder or the solder coat is made of Sn—Pb, S
The heat-fusable anisotropically conductive elastic connector according to any one of claims 1 to 5, which is at least one selected from n-Zn and Sn-Ag. 7. The heat-sealing powder has an average particle diameter of 0.1 mm or more.
The heat-fusable anisotropically conductive elastic connector according to any one of claims 1 to 6, which has a range of 1.0 mm. 8. The heat-fusible anisotropically conductive elastic connector according to claim 1, wherein the exposed area of the heat-fused powder is not more than half of the total surface area. 9. A mold having a molding space for obtaining a predetermined shape has a portion for localizing lines of magnetic force on a board surface and a concave portion for fixing heat fusion powder, respectively, independently of each other. After fixing the fusion powder in a predetermined concave portion, an unvulcanized elastomer mixed with a magnetic material serving as a main conductor is injected into a mold, the magnetic material is localized by a magnetic field, and the elastomer is cured by heating. Exposing the heat-sealing powder to at least one of the surface layers of the elastomer by using the heat-sealing type anisotropic conductive elastic connector. 10. A mold having a molding space for obtaining a predetermined shape has a portion for localizing lines of magnetic force at the same portion on the board surface, and a concave portion for fixing heat fusion powder. After fixing the fusion powder in a predetermined concave portion, an unvulcanized elastomer mixed with a magnetic material serving as a main conductor is injected into a mold, the magnetic material is localized by a magnetic field, and the elastomer is cured by heating. The heat-sealing powder is exposed to at least one of the surface layers of the elastomer, and the magnetic material and the heat-sealing powder are electrically connected to each other. Production method.