JPH0531820Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention is an anisotropically conductive elastomer connector (hereinafter simply referred to as a connector), particularly for various displays such as liquid crystal, EL, and plasma, facsimiles,
Connectors used to connect circuit boards to image sensor boards in copying devices, etc., where the board is made of glass, or where the electrodes on the board are extremely small in height, and circuit board connections using this connector. It's about structure.

[Prior Art] Conventionally, electrical connections between glass substrates and circuit boards in liquid crystal displays have been made using connectors or anisotropically conductive adhesive films, and for EL and plasma displays, the operating voltage and drive For methodological reasons, the connection is made by wire bonding or so-called FPC pressure bonding.

However, as liquid crystal displays become more colorful and have higher duty ratios, there is a need to reduce the contact resistance of connectors, which are connection members, and miniaturization of the connection pitch. It is difficult to satisfy this required characteristic with a so-called zebra-type connector, which is made by laminating and integrating conductive rubber and insulating rubber that have been added with a carbon-based conductivity imparting agent in alternating layers. This connection method also has problems in that the connection process is complicated and reliability is unstable. In addition, for EL displays and plasma displays, it is difficult to connect using conventional connection methods due to the finer pitches of connection terminals due to larger and finer display screens, and longer terminal array dimensions due to an increase in the number of terminals. There is a problem with this.

Therefore, for connectors used for this type of application, a large number of conductive fibrous substances are oriented in the thickness direction of an elastic insulating rubber sheet, and the conductive fibrous substances are placed on top of the insulating rubber sheet. A connector protruding from the lower surface has been proposed (Japanese Patent Publication No. 59-52487, Japanese Patent Publication No. 31043-1983, and Japanese Patent Publication No. 11402-1982).

[Problem to be solved by the invention] However, the above-mentioned connector in which a conductive fibrous material is oriented on an insulating rubber sheet is not suitable for the electrical connection between the display board and the circuit board of the above-mentioned display body. When the conductive fibrous material is pressed against the glass substrate, both ends of the conductive fibrous material protrude from both end surfaces of the insulating rubber sheet, causing the conductive fibrous material to slip or fall on the glass substrate, causing damage to display boards and circuit boards (hereinafter referred to as The board (simply referred to as the board) moves in the direction in which it falls, causing misalignment, making it impossible to align the board terminals, and pressing too hard can cause the conductive fibrous material to fall or break, causing connection failures. There is a disadvantage that
Furthermore, even if a connection is made, the adhesion between the conductive fibrous material and the board is poor, making it unstable against the effects of humidity, vibration, and shock, and condensation forms in the gap between the board and the board. If the conductive fibrous material is a metal wire or metal fiber, there is also the disadvantage that the terminal on the board may be damaged or disconnected during pressure welding.

[Means for Solving the Problems] The present invention relates to a connector that can solve these disadvantages and shortcomings.
A conductive fibrous material is oriented in the thickness direction of an insulating rubber sheet of 0.1 mm or more, and one end surface of the conductive fibrous material is placed on one surface of the insulating rubber sheet.
A protrusion with a dimension of 3 μm or more, preferably 5 μm or more and 30 μm or less, and a recess on the other surface of the insulating rubber sheet with a dimension of 3 μm or more and 30 μm or less, and a recess surrounding the depressed end surface. The present invention is characterized in that a connector is provided on the surface of the insulating rubber sheet, and this also relates to a connection structure in which a plurality of substrates are connected using this connector.

In other words, as a result of various studies on improving connectors that electrically connect circuit boards, the inventor of the present invention found that
In a known connector in which a conductive fibrous material is oriented on an insulating rubber sheet, the conductive fibrous material is arranged on one surface of the insulating rubber sheet in the same manner as in conventional connectors. The conductive fibrous material should protrude from the surface of the insulating rubber sheet, but the conductive fibrous material should not protrude from the other surface of the insulating rubber sheet.
On the other hand, if the conductive fibrous material is depressed from the surface and the insulating rubber sheet is provided with a concave portion that surrounds the depressed end surface, the connector can be interposed between the two substrates, and these Even when pressure-welded for electrical connection, this conductive fibrous material does not come into contact with glass substrates, etc.
The compressive deformation load is small, and the conductive fibrous material only comes into contact with the glass substrate when this pressure contact force is increased, and the compressive deformation load increases rapidly, making it easy to determine the contact and prevent conduction due to excessive pressure contact. In addition, in the initial state of pressure welding, the frictional force of the insulating rubber sheet holds the connector tightly fixed on the board, and also prevents the conductive fibrous material from sliding on the board. This prevents the board from falling or falling, which eliminates misalignment of the board and poor connections.In addition, the recessed area is sealed with the board, which prevents leakage and electrolytic corrosion caused by moisture such as condensation. In addition, when using this connector to electrically connect substrates such as glass substrates and metal substrates that have extremely small electrode heights, in other words, extremely thin terminals, it is important to use this connector with its conductive fibers. By pressing and sandwiching the material between multiple boards so that the depressed surface is in contact with these boards, the electrical connection is reliable and galvanic corrosion can be prevented, resulting in a stable electrically connected board connection structure. After discovering what could be achieved, the present invention was completed by conducting research on the insulating rubber sheet used here, the type of conductive fibrous material, the protrusion of the conductive fibrous material, the burial conditions, etc.

[Function] As mentioned above, the connector of the present invention has a thickness
A conductive fibrous material is oriented in the thickness direction of an insulating rubber sheet of 0.1 mm or more, and one end surface of the conductive fibrous material is protruded from one surface of the insulating rubber sheet. On the other surface, the other end surface of the conductive fibrous material is recessed from the surface, and a recessed portion surrounding the recessed end surface is provided on the surface of the insulating rubber sheet.

This insulating rubber sheet is silicone rubber,
It may be made of synthetic rubber such as EPDM rubber, urethane rubber, butadiene rubber, etc., but it has electrical insulation, heat resistance, cold resistance, weather resistance,
It is preferable to use silicone rubber, which has high reliability due to its compression set property. The thickness of this insulating rubber sheet can be manufactured as long as it is 0.1 mm or more, so 0.1 mm
or more, but from a practical point of view, it is recommended to have more than 0.2 mm in order to have flexibility in the design of the pressure welding dimensions, and to exhibit elasticity since the pressure welding is clamped, and to ensure a good pressure welding condition. Although there is no need to specifically limit the upper limit, this is a press-contact type connector, and from the viewpoint of miniaturization and thinning, it is common to set the connector to 20 mm or less.

On the other hand, it is essential that the conductive fibrous material oriented in the thickness direction of the insulating rubber sheet be conductive. Examples include metal materials such as alloys, aluminum, and gold, carbon fibers, and glass fibers coated with metal on the surface. Metal wires are considered useful in terms of reducing resistance, but materials other than gold is corrosion resistant,
From the viewpoint of contact reliability, it is preferable that the exposed end face be plated with gold. This shape may be any conventionally known shape such as a circular cross-section or a cylindrical shape, but in the case of a circular cross-section, the diameter is 10 μm ~
A range of 1.0 mm is sufficient. Also,
In order to prevent the conductive fibrous material from falling off or coming off the insulating rubber sheet during pressure welding or repeated compression, it is necessary to increase the adhesive strength between the insulating rubber sheet and the conductive fibrous material. Preferably, the means for this includes treating the surface of the conductive fibrous material with a silane coupling agent, or
An appropriate amount may be blended into the silicone rubber.

The connector of the present invention is made by orienting the above-mentioned conductive fibrous material in the thickness direction of the above-mentioned insulating rubber sheet with a thickness of 0.1 mm or more.
This requires that the conductive fibrous material protrudes from one surface of the insulating rubber sheet, and the conductive fibrous material is recessed from the other surface. Ru. The amount of protrusion of this conductive fibrous material needs to be at least 3 μm or more, preferably 5 μm or more, in order to make contact with the circuit board, but if it is too large, it may fall over or break when it is pressed against the circuit board. Therefore, this needs to be 30 μm or less. In addition, the depression depth of this conductive fibrous material on the other surface of the insulating rubber sheet must be at least 3 μm or more, preferably 5 μm or more, to prevent it from coming into contact with the glass substrate from the beginning of pressure bonding. If this depth is too deep, the pressing force required for contact with the glass substrate will become too large, so it is required to be 30 μm or less.

Note that when the conductive fibrous material is recessed on the other surface of the insulating rubber sheet, a recess, preferably a dome shape, is formed on the surface of the insulating rubber sheet into which the conductive fibrous material is recessed, surrounding the recessed end surface. It is necessary to provide a concave portion of In addition to reducing the compressive deformation load on the insulating rubber sheet until the material contacts the terminal, contact can be easily determined, and bending of the conductive fibrous material due to excessive pressure contact can be prevented, and the connector and board In addition, each recess is sealed with the substrate to form an independent closed space, which prevents the intrusion of moisture and other condensation. The advantage is that the probability that moisture will reach the conductive fibrous material involved in the conduction of adjacent electrodes is extremely small.

The connector of the present invention is used to electrically connect display glass substrates and substrates such as liquid crystal, EL, and plasma displays, and the substrate is a so-called PCB whose base material is made of glass epoxy or bakelite. or the base material is polyimide,
Made of film such as polyester, so-called
It is sufficient to use FPC, and the connection terminals of these are in most cases made of metal foil such as copper foil or conductive paste with a height of at least 10 μm, so the above-mentioned conductive fibers are attached to the connection terminals. Even if the conductive fibrous material protrudes when it comes into contact with a conductive fibrous material, it will not slip or move laterally and will dig into the connection terminal, improving the reliability of the connection. The connector of this invention uses a glass substrate with an extremely small electrode height.
It is said to be particularly useful for electrical connections between multiple substrates using metal substrates.

Next, the connector of the present invention will be explained based on the attached drawings. Figures 1 and 2 a and b schematically show longitudinal cross-sectional views of the connector of the present invention, and the thickness of this connector 1 is indicated by t as shown in Figure 1. A conductive fibrous material 3 is oriented in the thickness direction of the insulating rubber sheet 2, and the conductive fibrous material 3 is preferably 3 μm or more from one surface of the insulating rubber sheet 2. It protrudes with a protrusion amount of 5 μm or more and 30 μm or less, and the other surface is depressed from this surface to a depth of 3 μm or more, preferably 5 μm or more and 30 μm or less,
A recessed part 4 is provided to surround this recessed end face, and as shown in FIGS. It is preferable that it be formed into a shape.

Further, regarding the shape of the recessed portion, since it is preferable that the recessed portion is pressed evenly during pressure contact, when the conductive fibrous material has a circular or elliptical cross section, it is formed in a concentric shape, If its cross section is rectangular or polygonal, it is formed concentrically with its circumscribed circle. The size and position of this circumscribed circle are larger than or equal to the diameter of the conductive fibrous material, or a larger circle or ellipse, or a circular shape larger than or equal to the diameter of the circumscribed circle, and the conductive fibrous material is It may be smaller than the pitch dimension arranged in the insulating rubber sheet, but for the purpose of preventing slippage during pressure connection of the connector, the pitch dimension should be 1/1/1 of the pitch dimension arranged in the insulating rubber sheet.
Approximately 2 to 2/3 is preferable. In addition, the periphery of the protruding part of the protruding conductive fibrous material is marked with the marks in Figure 2 a and b.
If the shape of the cavity of the press mold is set in advance so that the rubber 2a is provided in such a way as to gently wrap around the rubber 2a, as shown in FIG.

Moreover, FIG. 3 is a vertical cross-sectional view showing an example of the use of the connector of the present invention, in which the connector 1 is sandwiched between a glass substrate 5 as a display substrate and a circuit board 6 such as a PCB or FPC. When these are pressed together, the conductive fibrous material 3 protruding from one surface of the insulating rubber sheet 2 bites into the connection terminal 7 on the surface of the board and comes into contact with it, and the other surface of the insulating rubber sheet 2 As the connector is pressed, the conductive fibrous substance 3 that had been depressed on the surface becomes exposed and slightly protrudes from the surface of the insulating rubber sheet when it is pressed, and this becomes the connection terminal 8 on the glass substrate 5. This electrically connects the top of the glass substrate 5 and the circuit board 6, but the conductive fibrous material 3 that comes into contact with the connection terminals 8 on the glass substrate 5 is insulated by pressure welding. Since the rubber sheet protrudes from the surface of the rubber sheet, it does not slide on the glass surface, fall down, or break unlike the previously protruded rubber sheet, and has the advantage of stably contacting the glass substrate. In addition, the concave portion is sealed with the substrate and forms a closed space, which prevents moisture from entering, and moisture generated by condensation reaches the conductive fibrous material that is involved in the conduction of adjacent electrodes. The advantage is that the probability of this occurring is extremely small.

However, the depression depth of this conductive fibrous material is
If it is larger than 30 μm, for example 35 μm or more, and no surrounding recess is formed, the insulating rubber sheet may be deformed by pressure, especially the area around the recessed end surface, as shown in Figure 4. protrudes to obstruct the protrusion of the conductive fibrous material, in this case a gap 9 is created between the connection terminal 8 of the glass substrate and the conductive fibrous material,
This causes the inconvenience of not being able to make contact.

[Example] Next, examples of the present invention will be given.

Example: A copper wire with a diameter of 0.1 mm and a length of 5.5 mm is placed parallel to the width direction of the sheet at a pitch of 1 mm in the thickness direction of an unvulcanized silicone rubber sheet with a thickness of 20 mm and a width of 5 mm. After placing it so that it protrudes 0.7 mm from the surface, a second silicone rubber of the same size as the above silicone rubber is placed.
Position and overlap unvulcanized silicone rubber sheets, heat and pressurize at 170℃, 50Kg/cm ² for 5 minutes to obtain a sheet with a thickness of 18mm, a width of 5mm, and a copper wire of 1mm.
I got something that was arranged in pitch. Next, the protruding copper wire was cut with a slicer, and the silicone rubber layer on the other side was also cut with a slicer, so that one surface of the sheet had a protrusion of 25 μm and the other surface had a protrusion of 25 μm.
Make a silicone rubber sheet with a depression, and then add silicone rubber to the depression of the copper wire with a diameter of 0.4mm.
A dome-shaped recess was formed around the buried copper wire by cutting with a drill, and the connector of the present invention made of silicone rubber was manufactured.

Next, place this connector with a surface resistance on its surface.
A glass substrate with 30Ω indium oxide vapor deposited and electrodes formed at 3mm pitch and a 35μm thick layer on its surface.
The silicone rubber sheet was placed between a glass epoxy PCB board on which electrodes were formed at a pitch of 3 mm using copper foil so that the buried side of the copper wire was facing the glass board, and then pressed together with a pressure of 1 kg/cm ² . The copper wire that had been depressed on the surface was exposed to the surface of the silicone rubber sheet and protruded slightly, making contact with the connection terminal on the glass substrate, and the copper wire that was protruding from the other surface of the silicone rubber sheet connected to the circuit board. Since the contact was made by digging into the terminal, the glass substrate and the circuit board were completely electrically connected, and the connection resistance was 20 mΩ per electrode, making the connection resistance extremely low. Furthermore, no leakage due to condensation occurred even when heat shock tests and moisture resistance tests were conducted.

[Effects of the invention] As mentioned above, the connector of the invention has a thickness of
A conductive fibrous material is oriented in the thickness direction of an insulating rubber sheet of 0.1 mm or more, and one end surface of this conductive fibrous material is 3 μm thick on one surface of the insulating rubber sheet.
Above, the protrusion has a dimension of 30 μm or less, and the other end surface has a protrusion of 3 μm or more on the other surface of the insulating rubber sheet.
The insulating rubber sheet is characterized by being depressed to a size of 30 μm or less and having a concave portion surrounding the depressed end face on the surface of the insulating rubber sheet, which is placed between the substrates. When installed and press-contacted, this protruding part digs into the connection terminal on the circuit board and comes into contact with it, and as the depressed end surface is compressed, it is exposed to the surface of the insulating rubber sheet and protrudes slightly, making contact with the board. However, since it does not slip or break at this time, the compressive deformation load on the insulating rubber sheet is reduced, and contact can be easily determined, preventing the conductive fibrous material from breaking due to excessive pressure contact. This improves the adhesion between the connector and the board and increases contact reliability.Furthermore, the recess is sealed with the board to form a closed space, which prevents moisture from entering.
Further, there is an advantage that the probability that moisture generated by dew condensation reaches the conductive fibrous material involved in the conduction of adjacent electrodes is extremely small, and electrical connection between these materials can be easily and advantageously performed.

[Brief description of the drawings]

Figures 1 and 2 are longitudinal cross-sectional views of the connector of the present invention, Figure 3 is a vertical cross-sectional view of an example of the use of the connector of the present invention, and Figure 4 shows the depression depth of the conductive fibrous material.
FIG. 12 shows a longitudinal cross-sectional view of a comparative example of a connector in use, which is larger than 30 μm and does not have a surrounding recess. 1 ...Anisotropically conductive elastomer connector, 2...
...Insulating rubber sheet, 3...Conductive fibrous material,
4... Recessed portion, 5... Glass substrate, 6... Circuit board, 7... Connection terminal, 8... Connection terminal, 9... Gap.

Claims (1)

[Claims for Utility Model Registration] 1. Conductive fibrous material is oriented in the thickness direction of an insulating rubber sheet with a thickness of 0.1 mm or more, and one end surface of the conductive fibrous material is attached to the insulating rubber sheet. A protrusion with a dimension of 3 μm or more and 30 μm or less on one surface of the insulating rubber sheet, and a depression of the other end surface with a dimension of 3 μm or more and 30 μm or less on the other surface of the insulating rubber sheet, and a recess surrounding the depressed end surface. 1. An anisotropically conductive elastomer connector, characterized in that an anisotropically conductive elastomer connector is provided on the surface of the insulating rubber sheet. 2. The anisotropically conductive elastomer connector according to claim 1 is placed between a plurality of circuit boards in which at least one of the circuit boards is a glass substrate or a metal substrate with a small electrode height. A circuit board connection structure characterized in that a conductive fibrous material is pressed and clamped so that the recessed surface is brought into contact with the above-mentioned glass substrate or metal substrate.