JPS6331904B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a new and improved electrical connection structure and method.

Conventionally, when connecting the lead-out terminals of two printed circuit boards of the same or different types, or when connecting the connecting terminal of a flat cable wire to the lead-out terminals of a printed circuit board, it is necessary to A hot melt adhesive or a thermosetting adhesive in a B stage state is interposed on this contact surface, and the surfaces of the lead terminal and the connecting terminal consisting of the parallel conductive paths are brought into surface contact. A method is known in which the contact portion is adhesively connected and integrated under heating and pressure by applying solder plating or imparting conductivity to the adhesive.

However, in such conventionally known connection methods and connection structures obtained thereby, conductive adhesive or solder that exhibits fluidity when heated is disposed flatly under heating and pressure during the connection operation. It is easy to short-circuit between adjacent terminals, so the terminal arrangement pitch can only be about 1.2 mm at most.
For example, as seen in U.S. Pat. No. 3,638,163, it is difficult to obtain a connection structure in which one or more terminal electrodes need to be in contact with one terminal electrode of the other. Furthermore, even with a one-terminal-to-one-terminal connection structure, when trying to improve work efficiency in the mounting process, connection failures tend to occur and reliability is lacking, which are disadvantageous and disadvantageous.

The present invention addresses the disadvantages of such conventional connection structures;
The present invention provides a new and improved electrical connection structure which solves the drawbacks, and which consists of an extraction terminal electrode consisting of parallel conductive paths arranged on the surface of an insulating substrate and a parallel conductive path arranged in a plane. A parallel conductive path having flexibility on one side with a connecting terminal consisting of the parallel conductive path is formed such that a groove extending in a direction intersecting the parallel conductive path is formed in a plane defined by the parallel conductive path. The top of each of the parallel conductive paths protruding due to the bending is made to face the other parallel conductive path arranged opposite thereto, and defined by the one parallel conductive path in the vicinity of the connection point. The gap formed between the surface defined by the parallel conductive path and the opposite parallel conductive path is filled with a connecting organic polymer material formed by dispersing and blending low-melting point conductive particles, The method is characterized in that the conductive particles present between the opposing conductive paths are melted to electrically connect the opposing conductive paths. When connecting a connection terminal consisting of parallel conductive paths arranged in a plane to a lead-out terminal electrode consisting of conductive paths,
The above-mentioned lead-out terminal electrode and the connection terminal are disposed facing each other, and a layer of an adhesive organic polymer material made of a dispersed mixture of low-melting point conductive particles that melts under heat and pressure is interposed between them. A pressing jig having at least one protrusion on its abutting surface is pressed onto the back surface of the flexible parallel conductive path under heating to form a surface defined by the flexible parallel conductive path. The flexible parallel conductive path is bent so that a groove extending in a direction intersecting the parallel conductive path is formed, and the low melting point conductive particles present between the lead terminal electrode and the connecting terminal are melted. The present invention relates to an electrical connection method characterized by electrically connecting the above-mentioned opposing lead-out terminal electrodes and connection terminals.

Hereinafter, the present invention will be described in detail based on the accompanying drawings.

FIG. 1 shows a typical embodiment of the electrical connection structure according to the present invention, which is capable of connecting to a lead-out terminal section consisting of parallel conductive paths 11 provided on the peripheral edge 1a of a printed circuit board 1. It is formed by adhesively connecting the connecting terminal portions of a flat wire cable 2 on which parallel conductive paths 21 made of, for example, metal foil are provided on a flexible insulating tape, and the lead-out terminal portion of the circuit board 1. An adhesive organic polymer substance 3 made of low melting point conductive particles is filled and hardened between the flat wire cable and the flat wire cable. The flat wire cable 2 is curved so as to form a groove 4 as shown in the drawing, and by this, the lead terminal electrodes 11, 11, . and the connection terminals 21, 21, . A polymer substance 3 is filled and hardened, and the circuit board 1 and the flat wire cable 2 are firmly bonded and integrated by this molecular substance. Note that FIG. 2 shows another embodiment of the present invention, in which the flat wire cable 2 is
It is curved to form a book groove 4.

Therefore, the electrical connection structure of the present invention is as shown in FIG.
The connection is not limited to the connection between the circuit board 1 and the flat wire cable 2 as shown in FIG. 2, but also the connection between the lead terminals of two printed circuit boards, at least one of which is flexible; Alternatively, the lead-out terminal portion consisting of parallel conductive paths in a wiring glass substrate, thick film wiring ceramic substrate, etc. of a liquid crystal display device, EL panel, etc., the lead-out terminal portion of a flexible circuit board carrying these drive circuits, or the lead-out terminal portion of a flat wire cable. ICs for connections with connection terminals, as well as for lead-out terminals of various printed circuit boards,
It can be applied to connect lead terminals of flat packages such as LSI.

Furthermore, the surface of the lead-out terminal electrode and/or the connection terminal in the connection structure of the present invention may be soldered or the like may be applied as necessary, or the lead-out terminal electrode and/or the connection terminal itself may be made of a low-melting point metal material. According to this, the reliability of the electrical connection state between the connected conductive paths at the connection portion can be further improved.

On the other hand, regarding the matrix member of the adhesive organic polymer material 3, which is made of a dispersed mixture of low-melting point conductive particles that melt under heat and pressure, used in the connection structure of the present invention, this material is made of polystyrene, polyvinyl chloride, polyvinyl chloride, etc. Known hot melt adhesives based on vinyl acetate, polyethylene, polypropylene, polyamide, polyurethane, polyester, etc., or unsaturated polyester, epoxy resin, chloroprene, sulfonated rubber, silicone rubber, urethane rubber, SBR, NBR, acrylic rubber The thermosetting resin or rubber may be selected from thermosetting resins or rubbers such as asphalt resin, gilsonite, gran pitch, gramaite, etc., but it may also be a copolymer of two or more thereof. However, this material must exhibit adhesive properties by melting and/or plastic flow during hot press to connect the terminals to be connected, so this depends on its melting point and/or plastic flow under pressure. Range is 60~
It is adjusted to be selected from a range of 250℃,
It is also desirable to have thermoplastic flow within the range of 80 to 150°C, and to adjust various additives appropriately so that 80% or more of the curing is completed in a few seconds to several tens of seconds. Note that, if necessary, known coupling agents such as various silane compounds and organic titanium compounds, or rust preventive agents may be added to the material constituting the adhesive organic polymer material 3. It is necessary to disperse and blend various metal particles whose surfaces at least become molten (or sintered) by heating and are fused to the lead terminal electrode surface and the connection terminal surface.These metal particles include, for example, Tin, lead, silver, indium, cadmium, bismuth, antimony, zinc,
It is said to be a solder alloy of two or more types selected from copper, etc., or an aluminum alloy. Furthermore, in addition to the above-mentioned low-melting point metal particles, conductive metal particles such as carbon particles, nickel, and copper may be dispersed and mixed with the above-mentioned metal in the member constituting the adhesive organic polymer substance 3. . However, due to the dispersion and mixing of these low melting point metal particles or conductive metal particles, it is necessary that the adhesive organic polymer substance itself does not exhibit conductivity under normal conditions or under mere pressure. There is,
For this reason, the mixing ratio of these metal particles to 100 parts by volume of the adhesive organic polymer material is 40 parts by volume or less,
It should preferably be 30 parts by volume or less, more preferably 20 parts by volume or less.

In order to apply the adhesive organic polymer material 3 to the connection structure of the present invention, the polymer material is heated and melted or dissolved in a solvent, and the metal particles are mixed and dispersed therein. Next, a film-like or sheet-like molded product is formed according to various molding methods, and the product is cut into a desired shape, that is, according to the shape of the connected structure, and the resulting product is inserted between the parts to be connected. It is used by being arranged in a sandwich pattern or by being arranged in the form of a coating on the surface of the connected part.

In the present invention, solder plating or the like is applied to the surface of the lead terminal electrode and/or the surface of the connection terminal,
Alternatively, the lead terminal electrode and/or the connecting terminal may be made of a low melting point metal material, and various metal particles other than the low melting point conductive particles may be dispersed and blended into an adhesive organic polymer material that plastically flows under heat and pressure. are not considered mandatory, but by adopting the former and/or latter requirements,
It goes without saying that the reliability of the electrical connection between the connected conductive paths at the connection portion can be improved.

The electrical connection structure according to the present invention includes either an extraction terminal electrode consisting of parallel conductive paths arranged on the surface of an insulating substrate or a connecting terminal consisting of parallel conductive paths arranged in a plane, that is, a first In Fig. 2, parallel conductive paths 21 of the flat wire cable 2 are shown.
A connection terminal consisting of a wire is connected to the surface defined by the parallel conductive path 21, in other words, on the surface of the flat wire cable 2, so that a concave groove 4 extending in a direction crossing the parallel conductive path 21 is formed. The bent protrusion 21a of the parallel conductive path 21 is brought into contact with the surface of the lead terminal electrode 11, or the bent protrusion 21a is brought close to the surface of the lead terminal electrode 11. Conductive paths 2 facing each other under heat and pressure are interposed with various low melting point metal particles dispersed and mixed in the members constituting the organic polymer substance 3.
1, 21...... and extraction terminal electrodes 11, 11......
An electrical connection is achieved by melting (or sintering) the low-melting-point conductive particles existing between the two, and in this case, the electrical connection is at a location where an opposing conductive path and a terminal electrode are present. and parallel conductive path 21
The bending is performed only at or near the bent protrusion 21a, and the surrounding area is hermetically protected by the member constituting the adhesive organic polymer substance 3.

Next, the electrical connection method according to the present invention will be explained. For example, in the case of the connection structure shown in FIGS. 1 and 2, the peripheral edge 1a of the printed circuit board 1
The connection terminal part of the flat wire cable 2 is arranged opposite to the lead-out terminal part consisting of the parallel conductive path 11 provided in the flat wire cable 2, and the adhesive organic polymer substance 3 described above is molded between them. a tape-like film or sheet, or a coating film of the adhesive organic polymer substance 3 is provided on the surface of the lead-out terminal portion of the printed circuit board 1 and/or the surface of the connecting terminal portion of the flat wire cable 2; Next, one or two protrusions 5a, 5 are provided on the back surface of the flexible flat wire cable 2 on its contact surface.
For example, a pressing jig 5 as shown in FIG. 3 is brought into contact. In this case, the pressing jig 5 used is one that has been heated to a predetermined temperature in advance.
The pressing time, pressing force, heating temperature, etc. by this pressing jig 5 are appropriately selected depending on the composition and physical properties of the adhesive organic polymer substance 3. The contact surface of this pressing jig 5 is made of metal or a rubber elastic body with good thermal conductivity, and the above-mentioned protrusions 5a,
The height of 5b is 10 μm to 5000 μm, preferably 100 μm
~1000μm.

Incidentally, FIG. 3c illustrates a special form of the pressing jig 5 that can be used in the method of the present invention, and this has a plurality of protrusions instead of the protrusions 5a in FIG. 3a. 5c arranged in one row, and the arrangement pitch of the protruding parts 5c is determined by the pitch of the parallel conductive path 11 of the lead terminal part of the printed circuit board 1 or the connecting terminal part of the flat wire cable 2. By matching the pitch of the parallel conductive paths 21, a connection structure as shown in FIG. 4, for example, can be obtained.

That is, FIG. 4 shows that the pitch of the parallel conductive paths 11 at the lead-out terminal portion of the printed circuit board 1 is larger than the pitch of the parallel conductive paths 21 in the flat wire cable, and the pitch of the parallel conductive paths 11 matches the pitch of the former parallel conductive paths 11. The connection is made using a pressing jig having a protrusion 5c.

Therefore, in the electrical connection method of the present invention, when the pressing jig 5 is brought into contact with the back surface of the connecting portion of the flat wire cable, the heat contained in the pressing jig 5 causes the organic polymer to become adhesive. As the substance 3 plastically flows, only the low-melting point conductive particles existing between the conductive path and the terminal part with good heat conduction melt (or sinter), and the low-melting point conductive particles existing in other parts are heated. Since no pressure is applied, the portions in contact with the protrusions 5a, 5b or protrusions 5c of the pressing jig are bent and deformed as shown in FIGS. 1, 2, and 4 without melting. Electrical connection between the parallel conductive paths 11 and 21 is achieved, and the polymer material 3 extruded around the parallel conductive paths 11 and 21 during the bending deformation is cooled and hardened or solidified as it is, thereby maintaining the shape of the bending deformation part. At the same time, the bonding strength between the printed circuit board surface and the flat wire cable surface at the connection portion increases as the wire shrinks after curing or solidification.

As explained above, according to the present invention, the adhesive organic polymer substance is filled into the gap around the electrical connection between the opposing parallel conductive paths extending across the parallel conductive paths, and is cured or solidified. became
In addition, since only the low-melting-point conductive particles existing between the conductive path and the terminal portion melt (or sinter) to produce anisotropic conductivity, the effect of contractile force when this organic polymer material hardens or solidifies. In addition to increasing the bonding force between the objects to be connected underneath and making the electrical connection extremely reliable, the bulge extending across the parallel conductive path of the organic polymer material It acts as a thermal tamper and effectively prevents the dissipation of the heat applied by the pressing jig during the connection work.Furthermore, according to the present invention, the parallel conductive paths to be connected are not completely parallel, but are slightly parallel to each other. Even if they are placed opposite each other at an angle so that they partially intersect, the electrical connection between the opposing parallel conductive paths will extend across the parallel conductive path in a linear or band-like manner, and both sides of the connection will be insulated. There is no short circuit or contact between adjacent conductive paths because they are protected by a bulge of organic polymer material.
Therefore, the connection workability is improved, and its practical value is extremely great.

[Brief explanation of the drawing]

FIG. 1 shows a state in which the connecting terminal portion of a flat wire cable is connected to the lead-out terminal portion of a printed circuit board according to the present invention, and FIG.
is a perspective view thereof, and figure b is a sectional view of the connecting portion.
FIG. 2 is a sectional view of another embodiment corresponding to FIG. 1b. FIG. 3 shows a pressing jig used in carrying out the electrical connection method of the present invention, and FIGS. 3A, 3B, and 3C are perspective views of different embodiments, respectively. FIG. 4 is a sectional view of a state in which the connecting terminal portion of the flat wire cable is connected to the lead-out terminal portion of the printed circuit board using the pressing jig shown in FIG. 3c. DESCRIPTION OF SYMBOLS 1... Printed circuit board, 11... Parallel conductive path, 2... Flat wire cable, 21... Parallel conductive path, 3... Adhesive organic polymer substance, 4...
Pressing jig.

Claims (1)

[Scope of Claims] 1. Parallel conduction having the flexibility of either an extraction terminal electrode consisting of parallel conduction paths arranged on the surface of an insulating substrate or a connecting terminal consisting of parallel conduction paths arranged in a plane. The path is bent so that a concave groove extending in a direction intersecting the parallel conductive path is formed in the plane defined by the parallel conductive path, and the top of each parallel conductive path that protrudes due to the bend is bent to this. A surface defined by one of the parallel conductive paths and a surface defined by the other parallel conductive path facing the other parallel conductive path in the vicinity of the connection point. The gap formed between the opposing conductive paths is filled with an adhesive organic polymer material formed by dispersing and blending low-melting conductive particles, and the conductive particles existing between the opposing conductive paths are melted. An electrical connection structure characterized by electrically connecting opposing conductive paths. 2. When connecting a connection terminal consisting of parallel conductive paths arranged in a plane to an extraction terminal electrode consisting of parallel conductive paths arranged on the surface of an insulating substrate, the above-mentioned extraction terminal electrode and the connection terminal are placed opposite each other. A layer of an adhesive organic polymer material formed by dispersing and blending low-melting point conductive particles that melts under heat and pressure is interposed between these, and the back side of one of the above flexible parallel conductive paths. Then, a pressing jig having at least one protrusion on the contact surface is pressed under heating to apply pressure to the plane defined by the flexible parallel conductive path in a direction intersecting the parallel conductive path. bending the flexible parallel conductive path so as to form an extending groove;
An electrical connection method characterized by melting low-melting-point conductive particles present between the lead-out terminal electrode and the connection terminal to electrically connect the facing lead-out terminal electrode and the connection terminal.