JP2003060323A - Flexible circuit board having projecting terminal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flexible circuit board having a terminal with large mechanical strength, without the loss of the thinness of the flexible board. SOLUTION: In the flexible circuit board, the projecting end of a circuit pattern 3 is held, and this projecting part is a terminal 1, and a bending edge line 2 extending along the longitudinal direction is provided on the terminal. In a method for manufacturing the flexible circuit board having the projecting terminal, the flexible circuit board is prepared having a circuit pattern formed thereon, so that the projecting end is the terminal, and having on both of the upper and lower surfaces thereof an electrical conductor with surface-protecting layer formed thereon, and the flexible circuit board is press-molded, so that the bending edge line extending in the longitudinal direction and a bump for the terminal of the electrical conductor are formed on the electrical conductor.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flexible circuit board having terminals and a method for manufacturing the same, and more particularly to a structure for increasing the strength of the terminals and a method for manufacturing the same.

[0002]

2. Description of the Related Art As a component of an electronic device, a component having a terminal protruding outward is generally used. For example, as shown in FIG. 6, in a semiconductor integrated circuit, a group of terminals is formed on four peripheral edges of a package for connection with external elements.

The terminal for the battery power supply device disclosed in Japanese Patent Laid-Open No. 9-231953 is formed as a battery terminal in a battery pack.

These terminals are formed by punching or etching an electric conductor such as a metal plate or the like to form a lead frame or a desired shape as a circuit pattern, and an adhesive agent so that the terminal portions are exposed on the front and back. An insulating film is attached to form a surface protective layer using, and then punching or the like for outer shape processing is performed.

[0005]

In a circuit board having such protruding terminals, the protruding terminals need to have mechanical strength, and in order to achieve this, it is necessary to make the metal plate forming the terminals thick. There is.

On the other hand, the circuit board used for electronic equipment is
For ease of mounting and miniaturization, flexibility and thinness like a flexible circuit board are required, and providing a metal plate with a thickness goes against the requirement.

In order to obtain the strength of the terminal portion without increasing the thickness of the metal plate, as shown in Japanese Patent Laid-Open No. 61-208859, a finger-like projecting terminal in the lead frame is formed in the longitudinal direction thereof. There is a method of forming a groove along the groove.

This method constitutes a circuit and a terminal by plating, and requires a multi-step process such as formation of a resist layer, development, plating, and peeling. As a result, it is not suitable to provide a flexible circuit board having a strong terminal at low cost.

In addition to the above, as a flexible circuit board having protruding terminals, a copper clad laminate is used, a circuit pattern is formed on this copper foil by a well-known etching technique, and surface protection is performed on this circuit pattern. There are flexible circuit boards formed by forming layers and removing the base material. in this case,
The surface protective layer is formed by sticking a flexible insulating film or applying an insulating resin. Further, the base material is removed by ablation removal using an excimer laser or chemical etching treatment using a well-known polyimide etching solution. Also, it is the same in that a flexible circuit board having appropriate terminals cannot be provided by this technique.

The present invention has been made in view of the above points, and provides a flexible circuit board having terminals having high mechanical strength, the board portion having flexibility, and the thinness being maintained. The purpose is to do.

[0011]

To achieve the above object, in the present invention, a flexible circuit board is constructed so that an end portion of a circuit pattern is projected and held, and the projected portion serves as a terminal. In the terminal, the terminal is provided with a bent ridgeline extending along the longitudinal direction thereof, and a flexible circuit board having a protruding terminal, and a circuit pattern is formed so that the terminal has a protruding terminal. A flexible circuit board having a conductor having surface protection layers formed on both front and back surfaces is prepared, and the conductor is formed with a bent ridgeline extending in the longitudinal direction and a bump of a terminal of the conductor. An object of the present invention is to provide a method for manufacturing a flexible circuit board having a protruding terminal, which is formed by press molding a flexible circuit board.

[0012]

FIG. 1 is a perspective view showing the structure of a terminal in one embodiment of the present invention. As shown in FIG. 1, the terminal 1 is basically flat and has a bent ridge line portion 2 along its longitudinal direction. This bent ridge 2
Has a ridge line on the upper surface of the terminal 1 in the drawing, and has inclined surfaces on both sides in the longitudinal direction. Then, the tip end portion and the base end portion of the terminal 1 have flat portions, and between the flat portion and the inclined portion,
An oblique continuous portion is formed.

To form the bent ridge line portion 2, the terminal 1 is used.
The number of steps can be saved if the bending process is performed by press molding using a mold at the same time as the cutting of the outer shape or the outer shape punching of the flexible circuit board.

The bent ridge line portion 2 is formed in the central portion of the terminal 1 in the longitudinal direction and the width direction, and mainly gives the terminal 1 rigidity in the thickness direction, but also increases rigidity in other directions.

The terminal 1 is a portion of the circuit pattern 3 in the flexible circuit board protruding outside the board, and the circuit pattern 3 in the board is a surface protection layer 4 formed of an insulating film.
Is covered by.

FIG. 2 is a perspective view showing an embodiment of a terminal whose side shape is bent in a U shape. In this embodiment, the terminal 1 has a bent portion on the upper side in the drawing and a U-shaped portion on the lower side in the drawing.
It is bent along the longitudinal direction so that it has a V-shaped opening. Then, when the terminal 1 is viewed in the transverse cross section, it is almost U
One convex strip 5 having a V shape is provided straight along the longitudinal direction of the terminal 1.

In the embodiment shown in FIG. 2, the number of the ridges 5 is one, but it may be plural. The protruding direction of the ridge 5 may be arranged on the side in which the thickness of one ridge is different from that of the other ridge.

By bending the terminal 1 so that the side surface is U-shaped as described above, the terminal 1 has flexibility in the extending direction of the terminal 1 on the circuit board. As a result, if the material of the terminal 1 is elastic, the terminal 1 can contact the object with a contact pressure utilizing the elasticity. Then, the contact resistance can be reduced. Moreover, since the rigidity of the terminal 1 is increased by the ridge 5, the contact pressure can be further increased.

3 (a) and 3 (b) are a perspective view of an embodiment in which both sides of the terminal are bent to form a rising portion, and a cross-sectional view showing a cross-sectional shape of the rising portion. That is, as shown in FIG. 3A, both sides of the central portion in the longitudinal direction of the terminal 1 are bent downward at substantially right angles to form downward rising portions. The tip end and the base end of the terminal 1 are formed in a flat plate shape, and the rising width is gradually reduced between the flat plate portion and the central portion.

As shown in FIG. 3 (b), the lateral cross-sectional shape of the rising portion in FIG. 3 (a) taken along the line AA at the longitudinal center of the rising portion rises downward as shown in FIG. 3 (b). It has a shape.

FIGS. 4 (a) and 4 (b) are perspective views showing an embodiment in which the bump 6 is formed at the tip portion of the terminal 1 in the embodiment shown in FIG. 1 and a cross section taken along line BB thereof. It is a figure. Although the tip of the terminal 1 is formed to be flat, the bump 6 increases the rigidity and increases the contact pressure with respect to the object.

In order to form the bumps 6, the bumps 6 may be provided at the required positions of the terminals by press molding at the same time as the ridge bending process or at the same time as the outer shape punching process of the substrate.

FIG. 4 (b) is a sectional view taken along line BB in FIG. 4 (a).
The cross-sectional shape of the bump 6 when cut along a line is shown. The bump 6 has a shape that forms a part of a sphere that protrudes upward in the drawing, and can increase the rigidity in the thickness direction of the terminal 1. In addition, as shown in FIG.
The terminal 1 has a plated layer 7 formed on the outer surface of the base material.
The plating layer 7 can increase the rigidity of the entire terminal 1 by using a metal that is harder than the base material.

FIG. 5 is a perspective view showing still another embodiment of the present invention. In this embodiment, rigidity is imparted by bending the terminal 1 into an arc extending over the entire width of the transverse cross section, and an arc-shaped ridge line is formed instead of a streak shape.

(Modification) In the above embodiment, the center of the terminal,
Although a ridge line is formed on the side or the whole to give rigidity to the terminal, this ridge line may be any one as long as it produces an effect of substantially increasing the thickness of the terminal. Therefore,
For example, not only is there a plurality of ridges for forming a ridge line, but the ridges do not extend through the entire length, but short ridges may be arranged with appropriate intervals.

[0026]

As described above, according to the present invention, the flexible circuit board configured so that the end portion of the circuit pattern is projected and held and the projected portion is used as a terminal along the longitudinal direction. Since the terminal having the bent ridgeline that extends is provided, the substantial thickness is increased even if the metal plate material forming the terminal is thin, and the rigidity corresponding to the substantial thickness is provided.
Therefore, it is possible to form a terminal having a large contact pressure on a thin flexible circuit board while maintaining flexibility.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a configuration of a first embodiment according to the present invention.

FIG. 2 is a perspective view showing the configuration of a second embodiment according to the present invention.

FIG. 3 (a) is a perspective view showing a configuration of a third embodiment according to the present invention, and FIG. 3 (b) is a cross-sectional view taken along line AA of FIG. 3 (a). .

FIG. 4 (a) is a perspective view showing a configuration of a fourth embodiment according to the present invention, and FIG. 4 (b) is a cross-sectional view taken along line BB of FIG. 4 (a). .

FIG. 5 is a perspective view showing a configuration of a fifth embodiment according to the present invention.

FIG. 6 is an explanatory diagram showing a conventional connection structure in a semiconductor integrated circuit.

[Explanation of symbols] 1 terminal 2 ridge 3 circuit patterns 4 Surface protection layer 5 convex stripes 6 bumps 7 plating layer

Claims (6)

[Claims] 1. An end portion of a circuit pattern is projected and held,
In the flexible circuit board configured such that the protruding portion serves as a terminal, the terminal is provided with a bending ridge line extending along a longitudinal direction of the terminal. Circuit board. 2. The flexible circuit board having protruding terminals according to claim 1, wherein the bent ridge line has a gentle curvature in cross-sectional shape. 3. The flexible circuit board having protruding terminals according to claim 1, wherein the flexible circuit board has a surface protective layer made of an insulating film on both sides of the circuit pattern excluding the terminals. A flexible circuit board having protruding terminals. 4. The flexible circuit board having protruding terminals according to claim 1, wherein the terminals are provided with bumps and have protruding terminals. 5. A flexible circuit board having a conductor on which a circuit pattern is formed so as to form terminals with protruding end portions and surface protection layers formed on both front and back surfaces, is prepared. A method of manufacturing a flexible circuit board having protruding terminals, comprising press-molding the flexible circuit board so as to form bent ridges extending in a direction and bumps of the terminals of the conductor. 6. The method for manufacturing a flexible circuit board according to claim 5, wherein the bending ridgeline and the bump are simultaneously press-molded, and the flexible circuit board having a protruding terminal.