JPH0695463B2 - Heat seal connector for electric circuit connection and its connection method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a connection terminal of a display body such as an LCD, an EL, and a plasma display, a circuit board on which a driving part thereof is mounted, or a connection between boards of various electric circuits. The present invention relates to a heat-seal connector used in the above and a connecting method thereof.

[Conventional technology]

Generally, heat seal connectors are used for LCD, EL, LED, ECD,
It is used to connect a display such as a plasma display to a PCB, FPC, or between a PCB and an FPC, PCB, or between FPCs, but in recent years the display has become larger, colorized, more compact, or electronic devices have become smaller. The number of circuits has increased with the miniaturization, and the pitch of the connection pattern has been reduced to 0.3, 0.2, and 0.1 mm, and it has become necessary to reduce the resistance of the connection member.

In the past, metal was used for the conductive part of the connector, and this was connected with an anisotropic conductive adhesive.However, in order to connect with a lower resistance value, the conductive part is exposed and directly contacted with the connection pattern. Along with this, a structure has been adopted in which it is held by an adhesive provided between the conductive parts.

[Problems to be Solved by the Invention]

However, in the case of using the heat seal connector b in which the conductive portion a is exposed as in the conventional case, as shown in FIG. 4, the exposed portion of the conductive portion, that is, the exposed portion in the slight portion from the heat seal portion to the resist film c, that is, The gap d remains on the circuit board e. As a result, electrolytic corrosion or migration is likely to occur due to dew condensation or the like, and the reliability of the electric circuit is significantly reduced, which is a problem.

An object of the present invention is to provide a connection structure of an electric circuit using a heat seal connector and an effective connection method, which solves the above conventional problems.

[Means for Solving the Problems]

According to the present invention, in the connection portion of the electric circuit pattern, the conductive portion is made of any one of a metal wire, a conductive paste, a metal foil, a metal thin film layer, or a combination thereof, and the conductive portion is exposed at the connection portion with the electric circuit. When connecting an electric circuit using a heat seal connector having a resist film on a portion other than the connecting portion, at least a portion of the resist film near the connecting portion has thermal adhesiveness, and the electric circuit It is characterized in that the conductive portion is covered by heat-sealing a part of the resist film at the time of heat-sealing connection with, and the exposed portion of the connecting portion is eliminated.

[Action]

To connect an electric circuit using the heat-seal connector provided with the resist film of the present invention, heat is applied while crimping the resist film on the electric circuit pattern of the electrically insulating base material on the circuit board. Once connected, this connection can prevent water from entering the continuous part due to condensation, etc., reducing the risk of electrolytic corrosion and migration.
The connection structure of the electric circuit has higher reliability.

〔Example〕

The present invention will be described with reference to FIGS. 1 and 2 where a conductive pattern 4 is provided together with a heat-adhesive adhesive 3 on a base film 2 serving as an electrically insulating base, and a non-heat-adhesive resist film 7 is used for polymerization coating. The heat-sealable connector film 1 is formed by polymerizing and laminating a heat-adhesive resist film 5 which serves as a heat-adhesive portion on the connection portion formed at one end thereof. That is, as the heat seal connector 1, a conductive metal is used for the conductive portion in order to reduce the resistance, the conductive pattern 4 is exposed at the connection portion, and the heat adhesive adhesive 3 is provided between them. And can be connected by heat sealing.

The substrate used for the heat seal connector of the present invention is
It can be used as long as it has electrical insulation, but considering heat conductivity and heat resistance during heat sealing, it is 1 of PET or PI.
It is preferable to use a film of 0 to 200 μm, preferably a film of 20 to 100 μm.

In this case, examples of the form of the metal used for the conductive portion include a conductive metal wire, a conductive paste, a metal foil, and a metal thin film, and the metal wire includes Cu, SUS, phosphor bronze, brass, beryllium copper, Ni, etc. Other examples are metal wires plated with Au, Ag, Pd, etc., but from the viewpoint of strength and formability of metal wires, those made of Ni, brass, phosphor bronze are preferable, and connection resistance should be considered. Then, it is more preferable that the layer is covered with Au. The conductive paste is Ag paste, Au paste, Ag
-c paste is an example, but in terms of price and resistance, Ag
It is preferable to use a paste, and in consideration of migration resistance, it is best to use an Ag-c paste, and the compounding ratio of Ag-c paste is 50% by weight or more from the viewpoint of resistance. Further, in order to suppress the exposure of the Ag paste as much as possible, it is also effective to put the c paste on the Ag pesto.

As metal foil, Cu foil, Al foil, Cr foil, etc., and Au, S
What is plated with n, solder, Ni, etc. is further used as a metal thin film such as a plating layer provided on the conductor, an Au thin film formed by sputtering or vapor deposition on a conductor formed of a carbon paste, An example is an ITO thin film.

A generally known adhesive can be used as the heat-adhesive adhesive provided between the conductive parts of the connection portion of the heat-seal connector 1, and may be thermoplastic, thermosetting, or thermoplastic and thermosetting resin. The blend of. More specifically, thermoplastic adhesives include polyamide-based, polyester-based, ionomer-based, EVA, EAA, EMA, E
Examples include polyolefins such as EA, various synthetic rubbers, and modified products and composites of these. Examples of thermosetting adhesives include epoxy resin-based, urethane-based, acrylic-based, silicone-based, chloroprene-based, nitrile-based synthetic rubbers, and mixtures thereof.
From the viewpoint of preventing conduction failure due to springback,
It is preferably thermosetting, and it is preferable that it contains a one-component thermosetting epoxy resin from the viewpoint of reaction rate. In any of these cases, a curing agent, a vulcanizing agent, a control agent, a deterioration preventing agent, a heat resistance additive, a thermal conductivity improver, a tackifier, a softening agent, a coloring agent, etc. may be appropriately added. From the viewpoint of improving reliability, it is preferable that impurity ions are not included as much as possible, and addition of a metal deactivator may be considered.

Further, at least a portion of the non-heat-adhesive resist film 7 of the heat-seal connector 1 which is close to the connection portion must have a heat-adhesive property, but the heat-adhesive material used here is The same adhesives as the adhesives provided between the conductive parts can be exemplified.
Further, the adhesives at these two locations may be of the same kind or of different kinds, but it is preferable to select one having good compatibility from the viewpoint of completely eliminating the gap.

The electric circuit on the circuit board 8 is connected using such a heat seal connector 1, but at the time of connection, thermocompression bonding is performed by a heat seal head wider than the connection portion involved in conduction, or twice heat is applied. By crimping or the like, the connection structure of the electric circuit of the present invention in which the conductive portion is not exposed can be obtained.

In the specific example of FIG. 3, a conductive metal wire 6 is used as a conductive portion, and a heat-adhesive resist film 5 is continuously provided at one end of the non-heat-adhesive resist film 7 to expose the metal wire 6. The connection part was formed.

Example 1 A pattern of 0.4 mm pitch was formed by Ag paste on a 25 μm PET film, an adhesive layer was provided between them, and a resist film was formed with the same material as this adhesive. This heat seal connector was provided to intermittently apply pressure to the resist portion for heat seal connection with the circuit board.

In this case, apply a voltage of 50V between adjacent electrodes and
When left in 5% RH for 1000 hours, no electrolytic corrosion or migration was observed. Further, when the peel strength was measured, an average of 1500 mg / cm, which was a considerably high value, was obtained.

Example-2 A thermosetting adhesive was formed on a 25 μm PET film, and Ni Au-plated wires with a wire diameter of 20 μm were arranged at a pitch of about 80 μm so that about 2/3 of the wires were buried. On this, a heat-adhesive resist film was formed in a portion close to the connection portion, and a non-heat-adhesive resist film was formed in other portions.

Using this heat-seal connector, circuit boards having a pitch of 0.3 mm were connected to each other so as to be heat-sealed simultaneously with a resist layer having thermal adhesiveness. As in Example 1, a voltage of 50 V was applied between adjacent electrodes, and the temperature was 60 ° C. and 95% RH.
It was left inside for 1000 hours, but no leak due to electrolytic corrosion or migration occurred. Further, when the peel strength was measured, a fairly high value of 1.8 kg / cm was obtained.

〔The invention's effect〕

According to the present invention, the electric circuit pattern is exposed at the heat seal connection portion, and at least the portion of the resist film in the vicinity of the connection portion is provided with the heat adhesive portion, so that the conventional defects are eliminated and the heat seal is achieved. It is possible to make the connection of the electric circuit using the connector a reliable form,
It can be safely maintained in strength over a long period of time, and it helps prevent the exposure of conductive parts to prevent deterioration, greatly improves heat conduction, does not cause electrolytic corrosion due to condensation, does not cause leakage due to migration, and is a safe connection. The state can be maintained for a long period of time, and further, since the heat-adhesive resist film can have a sufficient thickness, an effect of improving peel strength can be obtained.

[Brief description of drawings]

FIG. 1 is a perspective view of a part of a heat seal connector used in the present invention, FIG. 2 is a vertical sectional view of a connection structure in a used state, and FIG. 3 is a perspective view of a part of another embodiment. The figure is a vertical cross-sectional view showing a conventional connection structure. 1 ... Heat seal connector, 2 ... Base film,
3 ... Thermal adhesive adhesive, 4 ... Conductive pattern, 5 ... Thermal adhesive resist film, 6 ... Metal line, 7 ... Non-thermal adhesive resist film, 8 ... Circuit board.

Claims (4)

[Claims] 1. A connector in which an electric circuit pattern is formed on an electrically insulating base material from any of a conductive metal wire, a conductive paste, a metal foil, a metal thin film layer, or a combination thereof, and which is covered with a resist film. The heat seal connector for electric circuit connection, wherein the electric circuit pattern is exposed at the heat seal connection portion, and the resist film at least in the vicinity of the connection portion has a heat adhesive portion. . 2. The heat-seal connector according to claim 1, wherein the conductive paste used for the conductive circuit pattern has a lower layer containing Ag and a surface layer containing carbon paste. 3. The thermal adhesive portion of the resist film is an adhesive layer containing a thermosetting component containing an epoxy resin.
Or the heat-seal connector according to 2. 4. A heat-sealing connector, wherein, at the heat-sealing connection part of an electric circuit pattern, when heat-sealing connection is performed with a heat-sealing connector, a heat-adhesive resist film adjacent to the connection part is thermocompression-bonded at the same time. How to connect the used electric circuit.