JPH0339890Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to an anisotropically conductive heat-adhesive connector, particularly an anisotropically conductive heat-adhesive connector for electrically connecting circuit boards to each other or between a circuit board and a display element. .

To connect the input/output wiring terminals of the circuit board and the input/output wiring terminals of display elements such as LCDs and LEDs, either prepare a separate socket-shaped part to connect the two, or use the corresponding terminals for both. The method of soldering one pair at a time has become common, but the work is complicated, and the latter method requires that the material of the circuit board be heat-resistant. In order to avoid these complications, there is a method of connecting the wiring terminals with thermal adhesive connectors.
For example, a method in which a conductive heating adhesive is provided only on the terminal section on the circuit board, a method in which the terminal itself is made of a thermally adhesive conductive material, or an insulating thermopressure adhesive between the wiring terminals on the circuit board. A method has been proposed in which layers are provided and corresponding terminals are forcibly bonded and fixed to each other. However, with the first two methods, short circuits are likely to occur during mounting due to contact between the connector and the circuit board or circuits that should not be connected, so they must be handled with care. If a separate insulating protective film is not provided to wrap around the connection, there is a disadvantage that short circuits are likely to occur, and the latter method requires advanced technology because the area where the adhesive can be applied is limited.
In particular, circuits with highly complex and high precision circuits have the disadvantage that the finished product becomes expensive.

The present invention relates to an anisotropically conductive heat-adhesive terminal connector that solves these disadvantages and shortcomings.This invention consists of 100 volume parts of a heat-adhesive flexible film material with a fiber diameter of 5 to 100 μm and a fiber length of 15 μm. A thermoadhesive flexible product made by dispersing and mixing 0.05 to 40 parts by volume of a conductivity imparting agent made of a conductive fibrous material with a diameter of ~300 μm and an aspect ratio of 3 or more so that the longitudinal direction of the fibers is parallel to the film surface. It is characterized in that a sexually anisotropically conductive film-like body is provided on a wiring pattern.

This will be explained below based on the attached drawings. Figure 1 is a perspective view of the connector according to the present invention, and Figure 2 is a diagram showing the connection between the connector according to the present invention and the connection terminal of a display element (not shown). It shows a partially enlarged longitudinal section.

That is, FIG. 1 shows a connector of the present invention in which a heat-adhesive flexible anisotropically conductive film-like body 3 is provided on a circuit board 1 having a wiring pattern 2. As shown in FIG. Since the connector of the present invention is connected to a display device such as an LCD or LED by thermocompression bonding, the material of this board 1 must be heat-resistant so that it will not soften due to the heat generated during connection. , preferably made of a flexible material capable of absorbing unevenness, such as a heat-resistant plastic such as polyamide, polyimide, or polyester, or a synthetic rubber such as silicone rubber or heat-resistant nitrile rubber, and having a thickness of 5 to 50%.
The film is 100 μm, preferably 10 to 50 μm.

On the other hand, the wiring pattern 2 can be formed by bonding and integrating a metal foil such as copper, aluminum, or stainless steel onto the base material 1, and then forming the desired wiring pattern by etching or the like, or by forming a desired wiring pattern using copper, nickel, silver, or the like.
It is said that a desired wiring pattern is formed using a printing method such as a gravure method or a screen method using a paint in which conductive particles such as gold or carbon are mixed with a binder such as epoxy or urethane. The wiring pattern is formed, and if necessary, the surface is further plated with gold, solder, etc.
It may be provided with a protective film such as a carbon coat.

Next, the heat-adhesive flexible anisotropically conductive film-like material 3 provided on the substrate 1 having the wiring pattern 2 is made of plastic or rubber that becomes adhesive when heated, and a fibrous material dispersed and mixed therein. The conductivity imparting agent 5 is made of a material such as polyamide, polyester, ethylene-vinyl acetate copolymer, ethylene-acrylate copolymer, ethylene-methacrylate copolymer,
Examples include polyolefin copolymers such as ethylene-epoxy copolymers, epoxy resins, etc. Rubbers include silicone rubber, chloroprene rubber, nitrile rubber, and modified composites thereof, depending on the purpose of use. It is selected as appropriate based on various conditions such as temperature and pressure required to obtain adhesive strength suitable for. On the other hand, the anisotropic conductivity imparting agent 5 includes metals, alloys, and ceramics such as gold, silver, copper, lead, aluminum, magnesium, nickel, tungsten, titanium, bronze, cobalt, stainless steel, titanium nitride, and boron nitride. Fibers with a diameter of 5 to 100 μm are made by whisker method, vapor deposition method, melt spinning method, drawing method, shearing method, etc. ,
The fiber length is 15 to 300 μm, preferably 15 to 100 μm,
Examples include conductive fibrous bodies having an aspect ratio (fiber length/fiber diameter ratio) of 3 or more. The mixing amount of these conductivity imparting agents is 100% of the above film material.
If it is less than 0.05 parts per capacitance, the conduction density will be low and the reliability of the electrical connection will be low, while if it is more than 40 parts per capacitance, its conductivity will be reduced when it is heated and pressed. Unnecessary chains occur between the imparting agents, making it difficult to insulate in the direction perpendicular to the heat-pressing direction, making it impossible to maintain anisotropic conductivity.
The amount is 0.05 to 40 parts by volume, preferably 0.5 to 30 parts by volume, and more preferably 2 to 25 parts by volume. However, when using a conductive fibrous material as a conductivity imparting agent, it is necessary to orient the longitudinal direction of the conductive fibers almost parallel to the surface of the film material.
This means that conductive fibrous materials having a fiber diameter of 5 to 100 μm, a fiber length of 15 to 300 μm, and an aspect ratio of 3 or more are added to the film material in an amount of 0.05 to 0.05 to 100 parts by volume of the film material. After blending 40 parts by volume, this may be flowed out by applying shear stress in the flow direction in a fluid state, and the conductive fibers may be oriented in the flow direction.

The thickness of this anisotropically conductive film-like body should be set to 10 to
The thickness is 300 μm, preferably 10 to 100 μm, and more preferably 10 to 70 μm. If it is necessary to temporarily fix this anisotropic conductive film to a wiring board, a separate adhesive layer is often provided at the necessary locations, and the above-mentioned conductivity imparting agent is mixed into this adhesive. This is considered optional. When an anisotropically conductive film material is hot-pressed in its thickness direction, it exhibits conductivity in its thickness direction due to contact between the conductivity-imparting agents contained therein, but in the direction perpendicular to this, it exhibits conductivity. It still exhibits insulating properties in some lateral directions. In addition,
This anisotropically conductive film-like material is also thermally adhesive, so when it is placed over the terminals of a display device and hot-pressed, the two are bonded together and at the same time becomes conductive only in the thickness direction. The wiring pattern 2 of the invented connector and the contact terminals of the display element are electrically connected reliably. Figure 2 shows this, and when the anisotropically conductive film-like body 3 laminated on the wiring pattern 2 and the connection terminal 4 of the display element (not shown) placed on this are hot-pressed. , this anisotropically conductive film-like body 3 is thermally adhesive, and at the same time,
The conductivity imparting agent 5, which has been dispersed and mixed and oriented in the anisotropically conductive film-like body 3 by this heat pressure, comes into contact with each other while maintaining its oriented state, and Since conductivity is exhibited only in the direction, the wiring pattern 2 and the connection terminal 4 of the display element are electrically connected through the anisotropically conductive film-like body 3, which is practical.

The length, diameter, and aspect ratio of the conductive fibrous material used as the conductivity imparting agent used in the present invention must be within the above-mentioned range. If it is smaller than 2.8, even if it is blended into a film material and then flowed out in a fluid state in the flow direction, it will not be oriented along the flow direction, and therefore it will be difficult to align it parallel to the film surface. Therefore, in practice, this aspect ratio is set to 3 or more. Similarly, if the fiber diameter is smaller than about 4 μm, it is too small and easily affected by the flow (turbulent flow), and the direction is likely to be fixed in the turbulent flow, and if the fiber length is smaller than 13 μm, it is not affected by the flow. On the other hand, if the fiber length exceeds 300 μm, it becomes easy to get entangled with adjacent fibers, making it difficult to orient the fibers in the flow direction. It becomes difficult to connect extremely small pitches, and the fiber diameter decreases.
If it exceeds 100 μm, it will become too large and the flow resistance will become too large, promoting turbulent flow and making it difficult to achieve proper orientation. 100μ
The fiber length is 15 to 300 μm.

In the connector of the present invention, the blending ratio, fiber diameter, fiber length, and aspect ratio of the conductive fibrous material used as the conductivity imparting agent are specified as described above, so it is necessary to This conductive fibrous material is oriented parallel to the film surface, as if the flexible anisotropic conductive film material layers d ₁ , d ₂ . . . (See Figure 2) is sheared and coated in multiple layers, resulting in a good dispersion orientation of the conductive fibers, and the conductive fibers are more evenly dispersed. Since the fibers are in contact with each other along their ridges due to their shape, the contact area between the fibers on the same horizontal projection plane is longer than that of point contacts such as conductive particles, which increases reliability. High conductivity can be obtained.

In addition, although the connection and continuity between the wiring pattern and the connection terminal of the display element have been explained above,
It goes without saying that this can also be used, for example, to connect connection terminals of solar cells and other electrical and electronic components. Note that a hot trowel is usually used in these hot pressing methods;
Conventionally known heat pressing methods such as a high frequency welder, an ultrasonic welder, and an impulse sealer may be used.

The connector according to the present invention has higher continuity reliability than when a simple insulating adhesive is used, and to obtain the connector according to the present invention, it is necessary to simply attach an anisotropically conductive film-like body to a desired wiring pattern. Since it is only necessary to provide the wiring pattern on the circuit board that has the wiring pattern, it has the advantage of not being restricted by the pattern shape of the wiring pattern on the circuit board, and as a result, the degree of freedom in design increases. Furthermore, the anisotropically conductive film-like body used in the present invention is easily produced and has a high yield, so it has the advantage of being economically inexpensive.

Next, examples of the present invention will be given.

Example 1 A circuit board was made by printing a parallel striped wiring pattern with a pitch of 16 mm using carbon paint on a polyester film with a thickness of 50 μm, and on this, 100 parts by volume of polyester thermal adhesive with an average diameter of 9 μm and an average length of 60 μm were applied.
The anisotropically conductive heat-adhesive connector of the present invention was obtained by dispersing and mixing 10 parts by volume of carbon fibers and forming the resulting anisotropically conductive film-like body into a film.

Next, place a 12mm wire on the corresponding part of this connection terminal.
When the connection terminals of an LCD display element with pitch-spaced connection terminals were stacked and heated at 140°C and 20 kg/cm ² for 10 seconds, the circuit board and LCD display element were completely bonded, and the terminal electrodes of those The electrical resistance was 4.5KΩ, indicating that they were connected, and that there was no unnecessary leakage.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of the anisotropically conductive heat-adhesive connector of the present invention, and FIG. 2 is a partially enlarged longitudinal cross-sectional view of the connector when it is connected to a connecting terminal of a display element. DESCRIPTION OF SYMBOLS 1... Substrate, 2... Wiring pattern, 3... Heat-adhesive flexible anisotropically conductive film-like body, 4... Connection terminal for display element, 5... Conductivity imparting agent.

Claims (1)

[Scope of utility model registration request] 0.05 to 40 parts by volume of a conductivity imparting agent made of a conductive fibrous material having a fiber diameter of 5 to 100 μm, a fiber length of 15 to 300 μm, and an aspect ratio of 3 or more to 100 parts by volume of a heat-adhesive flexible film material. An anisotropically conductive heating device characterized in that a heat-adhesive flexible anisotropically conductive film-like body formed by dispersing and blending fibers such that the longitudinal direction of the fibers is parallel to the film creeping surface is provided on a wiring pattern. Adhesive connector.