JPH11195850A - Flexible printed board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an excellent repeated-folding-resistance applied to a hing part and movable connection point between electronic units by folding a single- side flexible printed board part over another single-side flexible printed board part, which is to be a bent part. SOLUTION: Related to a flexible printed board(FPC) 1, both end parts in a longitudinal direction are both-side FPC part III while an intermediate part, in longitudinal direction, forming a fork is a single-side FPC part 11 constituting a bent part. The FPC part II can constitute a bent part which is to be applied to a movable connection part of an electronic unit, etc., both the single-side FPC parts II do not, substantially, interfere or constrain each other at repeated bending operation, so the benefit as a single-side FPC, in other words, excellent durability (bending resistance) is provided. In addition, problem of less wiring pattern is settled.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a flexible printed circuit board.

[0002]

2. Description of the Related Art For example, a flexible printed circuit board (hereinafter, referred to as an FPC) is generally used to electrically interconnect two electronic units rotatably connected about a hinge portion. Generally, an FPC can be divided into a double-sided FPC having a wiring pattern on both sides and a single-sided FPC having a wiring pattern on only one side. The double-sided FPC has a smaller number of wiring patterns than a single-sided FPC. Excellent, but bending resistance (repeated bending resistance)
Is less than or equal to 1 of 10, which is known to be inferior in that respect.

For this reason, it is the single-sided FPC that is arranged so as to straddle the hinge portion of the electronic unit and forms a bent portion mainly in consideration of durability. As an example of this,
Japanese Patent Application Laid-Open No. 8-125299 discloses that a single-sided FPC is used for electrical connection between two units. In particular, in order to eliminate the small number of wiring patterns on one side, an intermediate wide-width single-sided FPC portion is used. Are overlapped to reduce the width of the portion, and the overlapped portion is stored in a hinge portion.

[0004]

However, although it is appropriate for all conventional structures including the structure disclosed in the above publication,
As long as the single-sided FPC is basically used, the small number of the wiring patterns does not fundamentally solve the problem. Therefore, in the present invention, a bending portion having excellent repetition bending resistance that can be applied to a hinge portion and a movable connection portion between electronic units is provided, and further, the small number of wiring patterns can be fundamentally solved, that is, It is an object of the present invention to provide an excellent flexible printed circuit board having both the advantages of a double-sided FPC and the advantages of a single-sided FPC.

[0005]

A flexible printed circuit board according to the present invention is a single flexible printed circuit board including a double-sided flexible printed circuit board portion and a single-sided flexible printed circuit board portion. The configuration is characterized in that the flexible printed board portion is bent and overlapped on another single-sided flexible printed board portion, and the overlapped portion is formed as a bent portion. Since the single-sided flexible printed circuit board constitutes the bent portion, the bending performance is excellent, and the number of wiring patterns can be increased due to the presence of the double-sided flexible printed circuit board.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a plurality of embodiments of the present invention will be described with reference to the drawings. F of the present embodiment shown in FIG.
The PC (flexible printed circuit board) 1 has a double-sided FPC portion at both ends in the longitudinal direction (a portion indicated by III), and an intermediate portion in the longitudinal direction such as a bifurcated portion has a single-sided FPC portion (a single-sided FPC portion). II). In the other figures, the portion indicated by III is a double-sided FPC portion, and the portion indicated by II is a single-sided FPC portion.

The double-sided FPC portion (III) comprises a central insulating base material 3 (for example, a polyimide film having a thickness of about 25 μm) as a base and a conductor (for example, made of copper) laminated on both surfaces of the base material 3. A pattern layer 5, and a protective overcoat layer 7 formed by coating on both conductor pattern layers 5;
It is composed of Single-sided FPC (II) is double-sided FP
It is composed of only the same base material 3 as that of the part C (III), the conductor pattern layer 5 laminated only on one surface of the base material 3, and the overcoat layer 7 formed thereon by coating.

Further, at both ends of the illustrated FPC 1 in the longitudinal direction,
A connector section 9 for external connection is formed. FIG.
In (a), some wiring patterns (constituting the conductor pattern layer) that can be normally seen are drawn, but in FIG. 1 (b), they are omitted. Here, AA in FIG.
Please refer to FIG. 2 which is cut along the line and is seen obliquely from the front side.

In the bifurcated FPC portion (II), the right-hand side portion in FIG. 2 is a single-sided FP composed of the order of the overcoat layer 7, the conductor pattern layer 5, and the base material 3 from top to bottom.
The portion on the left hand side in FIG. 2 is a single-sided FPC portion composed of the base material 3, the conductor pattern layer 5, and the overcoat layer 7 from top to bottom.
The substrate (3) of (II) is also a substrate (3) of double-sided FPC (III)
Are also the same one (single).

The FPC portion (II) on the right hand side is bent downward around the fold line (CC), and
It is superimposed under the FPC part (II) on the left hand side. FIG.
(A) shows a state (unfolded) before bending, and FIG. 1 (b) shows a state after bending. B- in FIG.
As can be understood from FIG. 3 viewed from the direction of the arrow along the line B, the double-sided FPC portion (III) on the right hand side of FIG. 3 constituting the present FPC 1 is a bent portion (a white portion drawn in a rectangular shape). (The two single-sided FPC portions (II) overlap) and are connected to the FPC portion on the left hand side in FIG.

FIG. 3 shows two left-sided FPC portions (I
The FPC portion (which can overlap I)) can constitute a bent portion that is to be applied (arranged) to a movable connection portion such as an electronic unit (not shown). FPC part on both sides (II)
Do not substantially interfere with or restrict each other during the repeated bending operation, and thus can enjoy the benefits of a single-sided FPC, that is, excellent durability (bending resistance).

In addition, since the FPC of this embodiment is basically composed of a double-sided FPC (that is, both ends in the longitudinal direction are composed of a double-sided FPC), it can be compared with a conventional single-sided FPC. In addition, the number of arrangement patterns is remarkably excellent. Finally, for another embodiment,
Although the description will be made with reference to FIG. 4, the same reference numerals will be given to the parts and components common to the above-described embodiment, and the overlapping description will be appropriately omitted.

The FPC 11 of the illustrated embodiment has a double-sided FPC portion (III) at both ends in the longitudinal direction, and a single-sided FPC portion (II) that can form a bent portion at three intermediate portions in the longitudinal direction divided into three branches. It is. FIG. 4A shows a single-sided FPC portion (II) on the right hand side and a single-sided FPC portion (I
As shown in FIG. 4 (b), it is folded and overlapped on the central single-sided FPC portion (II).

A portion where the three single-sided FPC portions (II) overlap each other can constitute a bent portion which is to be applied (arranged) to a movable connection portion such as an electronic unit (not shown). As in the embodiment of FIG. 1 described above, in this embodiment, these three single-sided FPC portions (III) do not substantially interfere or restrain each other during the repeated bending operation.
The advantage as a single-sided FPC, that is, excellent durability (bending resistance) can be enjoyed.

Similarly, the FPC 11 is basically a double-sided FP
C (that is, both ends in the longitudinal direction are formed of double-sided FPCs), so that the number of arrangement patterns is remarkably superior to that of the conventional single-sided FPC. I have.

[0016]

As described above, according to the present invention, there is provided a bent portion having an extremely excellent repetitive bending resistance and a rational and economical solution which can fundamentally solve the small number of wiring patterns. A flexible printed circuit board can be realized.

[Brief description of the drawings]

FIGS. 1A and 1B are plan views of an FPC according to an embodiment of the present invention, in which FIG. 1A shows an unfolded state, and FIG. 1B shows a state in which an intermediate portion is folded and stacked.

FIG. 2 is a diagram cut along the line AA in FIG. 1A and viewed obliquely from an oblique front side.

FIG. 3 is a side view of a main part viewed from a direction of an arrow along a line BB in FIG. 1 (b).

FIGS. 4A and 4B are plan views of an FPC according to another embodiment, in which FIG. 4A shows a developed state, and FIG. 4B shows a state in which an intermediate portion is folded and overlapped.

[Explanation of symbols]

 1, 11 FPC 3 Base material 5 Conductive pattern layer 7 Overcoat layer 9 Connector section II Single-sided FPC section III Double-sided FPC section

Claims (1)

[Claims] 1. A single flexible printed circuit board including a double-sided flexible printed circuit board portion and a single-sided flexible printed circuit board portion, wherein the single-sided flexible printed circuit board portion is bent and overlapped on another single-sided flexible printed circuit board portion. A flexible printed circuit board characterized in that a portion is formed as a bent portion.