JPS61111595A - Connection structural body - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a connection structure used in various electronic devices.

[Conventional technology]

Generally, as shown in FIG. 3, a wiring pattern y (1d) consisting of a required Cu pattern is formed on a glass cloth epoxy substrate, and this is attached to, for example, an IC (la) (l) for driving a liquid crystal panel.
b) (In order to connect the rigid wiring board (1) to which 1 is connected and the liquid crystal spring /I/ (2p) thrown on the glass substrate (2) constituting the rigid wiring board, as shown in Fig. 4) For example, a wiring pattern (3b) made of striped Cu foil is formed on a polyimide flexible substrate (3a) having a thickness of 25 μm, and a wiring pattern (3b) is formed on this wiring pattern (3b). For example, the connection is made via a 7 lexiple wiring board (3) with a 25 μm thick polyimide coverlay (3).In this case, the rigid PCB (1) and the 7 lexiple wiring board (3) are connected. The flexible wiring board (3), the liquid crystal panel (21), and the glass substrate (2) are bonded using an adhesive containing conductive particles or conductive fibers, and the wiring patterns are connected to each other at this joint. are electrically connected, and other parts are mechanically connected.

An example of an adhesive containing conductive particles is a hot melt type insulating adhesive t4) in which solder metal particles (5) are added as a fraction. In further detail, this hot melt type insulating adhesive (4) has the following composition.

Insulating adhesive (4) of this composition has a solid content of 100%
10 parts by volume of low melting point solder metal particles (5) per part by volume
disperse. The metal particles (5) are made by dispersing low melting point solder metal particles (5) in an insulating adhesive (4) such as Pb-8n and connecting them to a thickness of 40 μm after drying. 6), and this connection sheet (6) is connected to the wiring pattern (ld) (or (2a)) on the rigid wiring board (1) (or (2)). Place it across the part to be connected to the wiring pattern (3b), and place it on top of it as shown in Figure 5 (,
The flexible wiring board (3) is connected to each wiring pattern (3).
The parts to be connected to each other are placed on the corresponding wiring pattern (ld) (or (2a) so that they extend in the same direction and overlap with each other via the connecting sheet (6), and both are connected to each other by 18
Pressure bonding is carried out at 40 kg/cm2 for 30 seconds at 0°C.

In this way, the hot-melt type insulating adhesive (4) in the connecting sheet (6) becomes fluid when heated, so that the two substrates (1) (or (2)) and (3) are Much of the insulating adhesive (4) interposed between the wiring pattern (Id) (or (2) and the corresponding wiring pattern (3b)) to which pressure is applied because it substantially protrudes from the surface. is pushed out to the side, and these wiring patterns (ld) (or (2a)) and wiring patterns (
3b), the solder metal particles (5)
As shown in FIG. 6, the wiring patterns (ld) (or (2a)) and (3) are melted and crushed by the thermal force DEEVC.
b) Both are soldered together! The insulating adhesive pad (4) is electrically connected to the wiring pattern 1c and is pressed outward from between the wiring patterns 7 (ld) (or Cza)) and (3b).
) wraps around the conductive metal solder particles (5) and adheres and fixes them.

Further, as an example of an adhesive containing conductive fibers, as shown in Fig. 7, carbon fibers (7) are mixed in a hot melt type insulating adhesive (4) oriented almost in one direction. For example, insulating adhesive (4) 1
Carbon fiber (7) 5 to 00 parts by volume
20 parts by volume of the carbon fibers (7) are oriented in almost one direction in the baths 5 to 5 to form a connected sheet (8) having a predetermined thickness, for example, 20 to 120 μm in a dry state. Connecting sheet (8) Connecting sheet (8)
Arrange the fibers so that the direction of the fibers matches the direction of the wiring pattern,
This was then heated and pressed in the same manner as in Figures 5 and 6.

[Problem that the invention seeks to solve]

A rigid wiring board (1) (or (2)) on which a predetermined wiring pattern has been applied to such 4 with an adhesive (4) containing particles (5 particles or conductive fibers (7)) and a predetermined wiring pattern. (3
When bonding a flexible wiring board (3) that has been subjected to b), this flexible wiring board (3) is often used by being bent, and at this bent part, the polyimide of this flexible wiring board (3) Since the flexible substrate (3a) and the coverlay (3) have a relatively strong restoring force, stress is applied to this joint, which can lead to poor conductivity and There was a risk of peeling etc.

In view of this, an object of the present invention is to prevent the joint from causing conduction failure, peeling, etc. due to the restoring force of the bent portion of the flexible wiring board (3).

Means for Solving Problem C] The present invention provides a predetermined wiring pattern (ld) (or (2a)
) Rigid wiring board (1) (or (2))
and a flexible wiring board (3) on which a predetermined wiring pattern (3b) has been applied are bonded using conductive particles (5) or conductive fibers (adhesive (4) containing force), and the wiring pattern is y (ld) (or (2a) ) (3b
) are electrically connected to each other and the other parts are mechanically connected. A reinforcing layer of metal (
9).

[Effect]

According to the present invention, the metal reinforcing layer (9) that prevents the bent portion of the flexible wiring board (3) from restoring due to bending is provided, so that the bent portion of the flexible wiring board (3) is prevented from restoring. (The stress caused by this restoration is not applied to the bonded portion, and there is no risk that this bonded portion will cause poor conductivity, peeling, etc.)

〔Example〕

Hereinafter, one embodiment of the connection structure of the present invention will be described with reference to FIGS. 1 and 2. In FIGS. 1 and 2, parts corresponding to those in FIGS. 3 to 7 are designated by the same reference numerals, and detailed explanation thereof will be omitted.

In this example, as shown in FIG.
The wiring pattern (1d) with a pitch of, for example, 0.3 mm is attached to the specified terminal of the rigid wiring board (1), and a swaying liquid crystal is placed on the transparent glass substrate (2) that grooves the rigid wiring board. For example 0.3 rnH of panel (2p)
In order to connect the wiring pattern (2a) consisting of i-pitch transparent electrodes, an adhesive (3
A wiring pattern (3b) consisting of a striped Cu foil with a thickness of 18 μm with a pitch of 0.3 mm is formed through the LC adhesive (3d) with a thickness of 25 μm on this wiring pattern (3b). The connection is made via a flexible wiring board (3) provided with a polyimide coverlay (3C) with a thickness of . In this case, the rigid wiring board (1) and the flexible wiring board (3) are bonded, and the 7 lexiple wiring board (3) and the liquid crystal panel (2p) glass substrate (
2) is joined with an adhesive (4) containing conductive particles (5) or conductive fibers, and at this joint, the wiring pattern -/ (ld) (2a) (3b) is electrically connected to each other. At the same time as the connection, the other parts are bonded, that is, mechanically joined, using adhesive (4) K.

In this example, nitrile butadiene rubber (NB
R) Ag0100 through a 50 μm thick adhesive a1
A reinforcing layer (9) with a thickness of μm is provided. In this case, when bonding the reinforcing layer (9) with this NBR adhesive, the temperature is 150°C.

Pressure is applied at 10 kg/cm2 for 20 minutes.

In addition, the reinforcing layer (9) is provided on the flexible base material (3a
) on top or coverlay (may be on 3rd place).

The rest of the structure is the same as that shown in FIG.

In this example, since the metal reinforcing layer (9) is provided as described above, this flexible wiring board (3) can be easily bent, and this flexible wiring board (3),! 7)
The restoring force of the bent part is fixed by the Ag reinforcing layer (9) in the bent state, so this reinforcing layer (9) suppresses the restoring force, and the rigid wiring board (1) (or (2)) and the flexible wiring board ( 3) The stress caused by this restoration on the bonded portion can be removed, thereby eliminating the risk of peeling due to poor conduction of this bonded portion, and improving the continuity reliability of this bonded portion.

Incidentally, in this example, the bending was done to a radius of 2 mm, and the above-mentioned bonding was carried out for 100 cycles, with 3 hours at 85°C and 3 hours at -30°C. did not occur.

As a comparative example, in the case shown in FIG. 3 in which the metal reinforcing layer (9) was not used, poor conduction and peeling occurred in the thigh after about 30 cycles.

In addition, as a reinforcing layer (9), a metal such as copper or zinc is added to a thickness of 100 μm.
The same effect as described above was obtained when laminated with NBR adhesive in the same manner as described above. In addition, this metal reinforcement layer (
The same effect as described above was obtained when an acrylic adhesive was used to bond 9) to the flexible wiring board (3)K.

FIG. 2B shows another embodiment of the present invention. In this Figure 2B, the coverlay of the 7 lexiple arrangement substrate (3) (50 μm4 acrylic adhesive or NB instead of 3) is used.
A 100 μm thick metal foil (9) made of aluminum, steel, etc. is thrown through the R-based adhesive a.

Of course, the effect of the above-mentioned colleague can also be obtained in the example shown in FIG. 2B.

In addition, in the above-mentioned embodiment, the thickness of the parallel reinforcing layer (9 mm) was changed to 100 mm.
μm, but this thickness is a flexible wiring board (3)
Of course, any material that can withstand the restoring force of the bent portion is sufficient. Furthermore, the present invention is not limited to the above-described embodiments; it goes without saying that various other configurations may be adopted without departing from the gist of the present invention.

〔Effect of the invention〕

According to the present invention, since there is a metal reinforcing layer (9) in the bent portion of the flexible wiring board that prevents the bending from restoring, the bending of the 7-flexible wiring board (3) becomes easy and the bent portion is restored. This has the advantage of improving the continuity of conduction at the joint, since no stress is applied to the joint due to this restoration, and the joint does not suffer from poor conductivity or peeling.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing one embodiment of the connected structure of the present invention, FIG. 2A is a partially enlarged sectional view showing an example of the main part of FIG.
Fig. B is a partially enlarged cross-sectional view showing the surface of another embodiment of the present invention, Fig. 3 is a perspective view showing an example of a connection structure, Fig. 4 is a cross-sectional view showing an example of a flexible wiring board, FIG. 5, FIG. 6, and FIG. 7 are diagrams for explaining the present invention. (1) is a rigid wiring board, (2) is a glass substrate, (3
) is a 7 lexiple wiring board, (4) is an insulating adhesive, (
5) is a conductive particle, (force is a conductive fiber, and (9) is a metal reinforcing layer.

Claims (1)

[Claims] A rigid wiring board with a predetermined wiring pattern and a flexible wiring board with a predetermined wiring pattern are joined using an adhesive containing conductive particles or conductive fibers, and the wiring patterns are electrically connected at the joint. In the connection structure in which the flexible wiring board is connected mechanically and the other parts are mechanically joined, a metal reinforcing layer is provided at the bent part of the flexible wiring board to prevent the flexible wiring board from restoring its shape when bent. A connection structure characterized by: