JPS5999786A - Flexible printed circuit board - 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] [Technical Field of the Invention] The present invention provides an auxiliary or
The present invention relates to a flexible printed wiring board having turns.

[Technical background of the invention]

In recent years, flexible printed circuit boards (hereinafter referred to as FPCs) have come into widespread use as electronic devices have become smaller, lighter, thinner, and more densely packaged.

Conventionally, as an FPC, for example, Fig. 1 (a)% (b)
The following are known. 1 in the figure is a flexible substrate made of polyimide resin or the like. A large number of through holes 2... are formed in this substrate 1, and the group Ap'
1 surface has a conductor pattern that connects the front i+F through holes 2, respectively: 31 1.3. p is provided. Said conductor pattern J! , 32 each have one bending part 41, 42. The portions of the through-holes 2 of the substrate 1 except for the second holes 5 are covered with a cover layer. Furthermore, two reinforcing materials 7, 7 are attached to both ends of the back surface of the substrate 1 using an adhesive or the like. Such a structure OFF'', Cy I is used by bending the substrate 1 along its longitudinal and lateral directions, as shown in Figure 2.

・[・Problems in background techniques and techniques] However, in the flexible printed wiring board having the above-described structure, when mounting components on the printed wiring board or when inserting the bent portion after mounting, the bent portion 42 of the conductor pattern 32 Stress is applied to the inner part 8 of the bending part 42, and this stress concentrates on the corner of the bent part 42, causing a crack 9 as shown in FIG.
There was a problem that disconnection occurred.

[Purpose of the invention]

The present invention was made in view of the arrangement circumstances, and its purpose is to provide a flexible printed wiring board that prevents disconnection at the bent portion of the conductor iR pattern on a flexible substrate. [Summary of the Invention] This invention The invention provides an auxiliary turn that is electrically disconnected from the conductive pattern on the inner side of the bent portion of at least one conductive pattern provided on the flexible substrate along the longitudinal direction of the substrate. This is intended to prevent disconnection at the bent portion of the conductor/mother turn on the substrate.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIG.

In the figure, parts that are the same as those of the conventional flexible printed wiring board shown in FIGS. 1(a) and 1(b) are given the same reference numerals, and their explanations will be omitted.

The flexible printed wiring board of the present invention is shown in FIGS.
Compared to b), when or after mounting components on the printed wiring board, the inside part 8 of the bent part 42 of the conductor pattern 32 on the flexible substrate 1 that forms the bent part is made of the same material as the conductor turns 31+32. and the same conductor pattern 31. ．． ?
The structure is such that an auxiliary groove 21 that is electrically disconnected from the conductive pattern 32 is provided along the conductive pattern 32.

According to the flexible printed wiring machine having the above structure, the bent portions 4 of the conductive patterns 32 of the flexible substrate 10
Since an auxiliary groove 21 is provided on the inner part 8 of 2, it is necessary to bend the parts when mounting them on the printed wiring board or after mounting them.

The stress applied to the auxiliary pattern 21 can be suppressed or prevented from concentrating on the corners of the conductive pattern 32. As a result, disconnection of the conductor pattern 32 can be avoided.

Moreover, since the auxiliary pattern 21 is not electrically connected to the conductor patterns 31+32, even if the auxiliary conductor 21 is disconnected, there will be no adverse effect on the equipment using this printed wiring board.

Further, since the auxiliary pattern 21 is made of the same material as the conductor patterns 31 and 32, the auxiliary pattern 21 can be formed at the same time when the conductor patterns 31 and 32 are formed, without increasing the number of man-hours.

In the above embodiment, the auxiliary pattern 21 is provided on the inner part 8 of the bending part 42 of the ψ body pattern 32, but the invention is not limited to this. ◇ The flexible printed wiring board according to the present invention is not limited to the one shown in FIGS. 4 and 5. For example, as shown in FIG.
Conductor patterns 231+232, respectively, are arranged in parallel, and the inner portion 24 of the bending part 222 of the conductor iR pattern 31 and the bending part 22. of the conductor pattern 232 are arranged in parallel. A structure in which auxiliary patterns 21' and 2Z' are provided on the inner part 25 of are arranged in parallel, and the outermost conductor i'? Turn 27. and the inner portion 28 of the bent portion 262 of the other outermost conductor pattern 27n. inner part 29 of
Effects similar to those of the embodiment can be expected even with a structure in which auxiliary patterns 21'' and 21〃 are provided on the sides, respectively.

〔Effect of the invention〕

As described in detail above, according to the present invention, it is possible to provide a highly reliable flexible printed wiring board that prevents disconnection at the bent portion of the conductor/gut on the flexible substrate.

[Brief explanation of the drawing]

FIG. 1(a) is a plan view of a conventional flexible printed wiring board, FIG. 1(b) is a cross-sectional view taken along line X-X in FIG. Fig. 3 is a partially enlarged view of the conductor/gutern of the flexible printed wiring board shown in Fig. 2; 5 is a plan view of a flexible printed wiring board according to an embodiment of the present invention, FIG. 5 is a perspective view illustrating a state in which the flexible printed wiring board shown in FIG. FIG. 7 is a perspective view for explaining a bent state of a flexible printed wiring board showing another embodiment of the present invention.01...Flexible board, 2...Through hole, 5...Land, 6 ...Coverlay, 7...Reinforcement material, 8.24, '25', 2
8.29...inner part, 27°21', 21''...
- Auxiliary pattern, 221.222. 261 p 262... Refraction part, 231+232+
271~27n...Conductor'',! turn. Applicant's agent Patent attorney Suzue Takehiko No. 3!l Figure 6 Figure 7

Claims (2)

[Claims] (1) At least one conductor provided on the flexible substrate along the longitudinal direction of the substrate. 1. A flexible printed wiring board characterized in that an auxiliary pattern is provided on the inner side of the bent part of the turn and is electrically disconnected from the conductor/gutter. (2) A plurality of conductors or turns are arranged in parallel on a flexible substrate in the longitudinal direction of the substrate, and the inner side of the outwardly bent part of the outermost conductor pattern with respect to the direction orthogonal to the longitudinal direction of the substrate. The flexible printed wiring board according to claim 1, characterized in that an auxiliary/main turn electrically connected to the conductive pattern is provided in a portion thereof.