JPH0697608A - Connection part structure of flexible circuit board and its forming method - Google Patents

Abstract

PURPOSE:To realize sure contact connection structure with other circuit board, by laminating and bonding an auxiliary plate wherein protruding parts are formed at specified part positions, to a terminal part rear of a flexible circuit board, and forming contact points type protruding parts corresponding with the protruding parts of the auxiliary plate, on the terminal part. CONSTITUTION:An auxiliary plate 5 wherein semi-spherical protruding parts 6 are formed at specified portions is manufactured by using a suitable resin plate. As to a flexible circuit board, connection parts 2 of a wiring pattern 2A are formed at part positions corresponding to the positions of the protruding parts 6 of the auxiliary plate 5, on the flexible insulating base member 1, by using conductive part member like a copper foil. The auxiliary plate 5 is arranged on the rear side of the flexible circuit board, and both of them are mutually bonded via adhesive agent 4. Protruding parts 3 which protrude in contact points type are formed at the connection parts 2 by the protruding parts 6 of the auxiliary plate 5. The shape of the protruding part 3 can be arbitrarily constituted by selecting the shape of the protruding part 6 formed on the auxiliary plate 5. Thereby sure contact connection structure with other circuit board can be realized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an auxiliary plate having a protrusion on the back surface of a flexible circuit board when connecting the flexible circuit boards to each other or connecting the flexible circuit board and the hard circuit board. The present invention relates to a connecting portion structure of a flexible circuit board in which a contact-shaped raised portion is formed in the connecting portion of the flexible circuit board by arranging the flexible circuit board and a method for forming the same.

[0002]

2. Description of the Related Art As a method for connecting flexible circuit boards to each other or connecting a flexible circuit board and a rigid circuit board to each other, for example, in addition to the dimple connection method shown in FIG. There is a bump connection method as shown in FIG.

In the dimple connection type structure, a flexible circuit board having a wiring pattern 12 adhered to a flexible insulating base material 15 via an adhesive layer 14 is prepared as shown in FIG. ,
A dimple portion 13 mechanically deformed into a dome shape is formed in a connecting portion of the flexible circuit board by a die, and the back surface of the dimple portion 13 is formed of a suitable elastic member 1 such as a synthetic resin plate.
The dimple portion 13 is connected to the connection on the mating circuit board 18 while the dimple portion 13 is supported by the protruding portion 17 formed in 6.

In such a dimple connection system, the dimple portion 13 in the form of a dome is formed only by deforming a thin flexible circuit board including a flexible insulating base material 15, an adhesive layer 14 and a wiring pattern 12. Since it is a structure that forms a dimple portion 1 that is extremely vulnerable to an external force during its manufacturing process or during or after being incorporated into a device, it is a dome-shaped dimple portion 1
3 is easily deformed.

Therefore, in this dimple connection method, it is difficult to improve the connection yield, and as described above, since the flexible circuit board cannot be incorporated into a device by itself, it has the protrusions 17. Elastic member 16 having elasticity
Therefore, it is necessary to provide deformation protection of the dimple portion 13 and contact reliability.

In any case, this dimple connection method requires the elastic member 16 at the lower portion of the flexible circuit board, which is disadvantageous in terms of cost.
If the alignment of the dimple portion 13 of the flexible circuit board 19 and the protrusion 17 of the elastic member 16 is not accurately performed as in the case of 1, the protrusion 17 may be deformed or the dimple 13 may be deformed. There is also an inconvenience that the positioning accuracy of is required.

Further, in this dimple connection method, since the dimple portion 13 is forcibly and suddenly deformed by a mold, at that time, the wiring pattern made of the flexible insulating base material 15 and the copper foil is used. -There is also a possibility that peeling from the
Further, since the minimum pitch and diameter of the dimples 13 are determined by the strength of the mold, it is impossible to cope with a high-density connection mode in which the dimples 13 are densely packed.

On the other hand, in the bump connection method, as shown in FIG.
As described above, since the bumps 20 are formed by printing after forming the wiring pattern 12 of the flexible circuit board, it is possible to control the variation of the height which is fatal to the reliability of the contact connection in addition to the increase in the number of steps. Is very difficult, resulting in a decrease in connection yield.

Further, this bump connection method also requires an elastic member 21 in the lower portion of the flexible circuit board as in the dimple connection method, which is also disadvantageous in terms of cost.

[0010]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides a flexible circuit board by bonding an auxiliary plate having a protrusion to the back surface of a connection portion of the flexible circuit board. A contact-shaped ridge is formed at the connection part of, thereby reducing the manufacturing man-hours and assembling man-hours of the flexible circuit board,
The present invention also provides a flexible circuit board connecting portion structure and a method of forming the same for high-density and highly reliable circuit board interconnection in which the contact-like ridges are not crushed.

Therefore, according to the present invention, an auxiliary plate having a protrusion of an arbitrary shape is provided at a required portion, and the connecting portion of the flexible circuit board is joined to the protrusion-forming surface of the auxiliary plate. A contact-shaped ridge corresponding to the protrusion of the auxiliary plate is formed at the connecting portion.

Further, in the case of adopting a structure in which an appropriate through hole is formed around the protrusion of the auxiliary plate to give elasticity to the protrusion, the flexible circuit board in the contact connection state with the counterpart circuit board is used. As a result, the contact-shaped ridge can appropriately absorb the unevenness of the other circuit board including the change over time.

[0013]

The present invention will be described in more detail below with reference to the illustrated embodiments. In FIGS. 1 and 2, reference numeral 1 is an insulating base material for a flexible circuit board, and a required number of wiring patterns 2A are formed on one surface of the insulating base material by etching a copper foil. The wiring patterns 2A can be terminated at the connecting portion 2, for example. Reference numeral 3 denotes a contact-shaped protruding portion which is formed on the connecting portion 2 and which is formed by a method described later and protrudes upward. Reference numeral 5 denotes an auxiliary plate made of an appropriate resin member.
Is integrally provided with a protrusion 6 for forming a contact-shaped raised portion 3 at a predetermined position, and the auxiliary plate 5 is provided with a connecting portion 2 in a flexible circuit board by using an adhesive 4. Also, the flexible circuit board connection portion according to one embodiment of the present invention is formed by pressure-bonding to the back surface of the predetermined portion.

In order to manufacture such a connecting portion structure of a flexible circuit board, as shown in FIG. 3, an auxiliary plate 5 having, for example, hemispherical projections 6 formed at predetermined positions is manufactured in advance with an appropriate resin plate member. On the other hand, with respect to the flexible circuit board, a wiring pattern is formed on the flexible insulating base material 1 at a position corresponding to the position of the protruding portion 6 of the auxiliary plate 5 with a conductive member such as copper foil. -Connecting part 2 of 2A is formed in advance. Then, when the auxiliary plate 5 is arranged on the back surface side of the flexible circuit board and is joined to each other through the adhesive 4, the protrusion 6 of the auxiliary plate 5 causes the connection part 2 to project in a contact-like shape on the connection part 2. 3 can be formed.

Here, the shape of the protruding portion 3 protruding like a contact point can be formed into a trapezoidal protruding portion 3A as shown in FIG. 4, depending on the shape of the protruding portion 6 formed on the auxiliary plate 5, for example. The shape of 3 can be configured arbitrarily according to the shape of the protrusion 6 of the auxiliary plate 5.

FIG. 5 shows a structure for imparting elasticity to the connection portion 2. For that purpose, for example, a U-shaped through hole 7 is formed in the peripheral portion of the projection 6 of the auxiliary plate 5 as shown in FIG. When the flexible circuit board is joined to the flexible circuit board in the state where the ridges are formed, since the peripheral portion of the protrusion 6 of the auxiliary plate 5 has an appropriate elasticity due to the action of the through hole 7, the connection portion 2 is accordingly The contact-shaped ridges 3 formed can also be configured to have elasticity, and therefore, the unevenness of the mating circuit board during manufacturing or the unevenness due to aging can be suitably absorbed to ensure reliable contact between the circuit boards. The connection status can be secured.

As a method of imparting such elasticity to the contact-shaped raised portion 3, as shown in FIG. 6, the periphery of the connecting portion 2 of the flexible circuit board is made to correspond to the through hole 7 of the auxiliary plate 5. It is also preferable to provide a U-shaped through hole 1A.

As described above, the structure for imparting elasticity to the connecting portion 2 can be provided in various forms. 7, 8 and 9 show specific examples thereof. First, (1) and (2) of FIG. 7 are suitable for the bottom portion of the auxiliary plate 5 at a portion corresponding to the connecting portion of the flexible circuit board. 8 shows a structure in which a recess 8 is formed and a through hole 9 having an appropriate shape is formed in a portion between the contact-shaped raised portions 3. Further, the structures (1) and (2) in FIG. The holes are formed in the flexible circuit board in common with the through holes 10.

Further, FIG. 9 shows an example in which a recess 11 is formed below the protrusion 6 of the auxiliary plate 5 so that the contact-like ridge 3 is appropriately elastic. Indicates.

[0020]

According to the structure of the terminal portion of the flexible circuit board and the method of forming the same according to the present invention, an auxiliary plate having a protrusion at a predetermined portion is laminated and bonded to the rear surface of the terminal portion of the flexible circuit board. Since the contact-shaped ridges corresponding to the protrusions of the auxiliary plate are formed in the terminal portion, the mechanical strength of the contact-shaped ridges in this terminal portion is high, and there is no fear of collapse or deformation. It is possible to obtain a reliable contact connection structure with the circuit board of the other party.

In addition, in the terminal portion structure of the flexible circuit board in which the through holes are provided around the protrusions of the auxiliary plate and around the terminal portions of the flexible circuit board, unevenness of the counterpart circuit board and aging Since the unevenness due to the dynamic change is appropriately absorbed, the contact connection state between the circuit boards can be favorably maintained.

The contact-shaped raised portion in the terminal portion of the flexible circuit board can be easily formed into an optimum shape by arbitrarily forming the shape of the protrusion of the auxiliary plate.

Since the auxiliary plate is in close contact with the back surface of the required connection portion of the flexible circuit board, the alignment process during assembly is simple, and the high density and highly reliable contact-like protrusions are provided. It is possible to provide an improved terminal structure.

[Brief description of drawings]

FIG. 1 is a conceptual perspective view of a terminal portion structure of a flexible circuit board constructed according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along the line AA.

FIG. 3 is a diagram for explaining a mode of laminating and joining a flexible circuit board and an auxiliary plate according to the present invention.

FIG. 4 is an explanatory view showing another shape of the contact-like raised portion in the terminal portion.

FIG. 5 is a perspective configuration diagram for explaining a structure for imparting elasticity to the contact-like raised portion of the terminal portion.

FIG. 6 is a perspective configuration diagram of a terminal portion according to another embodiment of the flexible circuit board having a structure in which a through hole is formed around the terminal portion of the flexible circuit board.

7A and 7B are a perspective configuration diagram and a BB line cross-sectional configuration diagram illustrating a structure for giving elasticity to a terminal portion of a flexible circuit board.

8A and 8B are a perspective configuration diagram and a CC line cross-sectional configuration diagram illustrating another structure for giving elasticity to the terminal portion of the flexible circuit board.

FIG. 9 is an explanatory cross-sectional view of a structure in which the auxiliary plate alone imparts elasticity to the terminal portion of the flexible circuit board.

FIG. 10 is a diagram for explaining a conventional dimple connection method.

FIG. 11 is a diagram for explaining the problem.

FIG. 12 is a diagram for explaining a conventional bump connection method.

[Explanation of symbols]

 1 Flexible Insulation Base Material 2 Terminal Part 2A Wiring Pattern 3 Contact-Shaped Protrusion 4 Adhesive 5 Auxiliary Plate 6 Projection 7 U-Shaped Through Hole 8 Cave 9 Elasticity-Providing Through Hole 10 Elasticity Through hole for imparting sex 11 Cave

Claims (10)

[Claims] 1. A flexible circuit board is provided with an auxiliary plate laminated and joined to the back surface of the connection part, the auxiliary plate having projections at predetermined positions corresponding to the positions of the connection parts. A connection part structure of a flexible circuit board, wherein the connection part has a contact-shaped protrusion protruding upward according to the shape. 2. The connecting portion structure of a flexible circuit board according to claim 1, wherein a through hole is provided around a protrusion of the auxiliary plate. 3. The flexible circuit board connecting portion structure according to claim 1, wherein the flexible circuit board has a through hole around a terminal portion thereof. 4. The connecting portion structure for a flexible circuit board according to claim 1, wherein a recess is formed on a bottom surface of the auxiliary plate located on the protrusion. 5. An auxiliary plate laminated and joined to the back surface of the connecting portion of the flexible circuit board, the auxiliary plate having a protrusion at a predetermined position corresponding to the position of the connecting portion, According to the shape, the connecting portion has a contact-shaped ridge protruding upward, and a through hole is provided at a portion of the auxiliary plate located between the contact-shaped ridges of the adjacent terminal portions. Structure of the connecting portion of the configured flexible circuit board. 6. The flexible circuit board connecting portion structure according to claim 5, wherein a through hole is also provided in a portion of the flexible circuit board located in the through hole of the auxiliary plate. 7. An auxiliary plate having a required number of protrusions formed at predetermined locations, and a flexible circuit board having a connection portion formed on one surface of a flexible insulating base material together with a required wiring pattern. And forming a contact-like raised portion on the connection portion by laminating and joining the auxiliary plate to the back surface of the connection portion in a state where the protrusion is located on the back surface of the connection portion. Method for forming connection part of flexible circuit board. 8. The connecting portion of the flexible circuit board according to claim 7, wherein the protrusion of the auxiliary plate is formed in a predetermined shape required to form the contact-shaped raised portion such as a hemisphere or a trapezoid. Forming method. 9. A flexible circuit board connecting portion according to claim 7, wherein an auxiliary plate having a through hole formed around said protrusion or an auxiliary plate having a recess formed on the bottom surface of said protrusion is used. Forming method. 10. The method for forming a connecting portion of a flexible circuit board according to claim 7, wherein a through hole is formed around the connecting portion of the flexible circuit board.