JPH1139953A - Flexible flat cable - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent breakage of a conductor resulting from vibration by providing a stress relaxation means on a wiring portion connecting both end terminal portions where plural rows of conductors arranged on insulation resin are exposed for soldering and covered with an insulation resin film. SOLUTION: Slits 7 or plural through holes as the cutout portions of a stress relaxation means are formed between the respective conductors 2 of a wiring portion 6 between both terminal portions 4 covered with an insulation resin film 5 in plural rows of conductors 2 on a heat resistant insulation resin 1. Thereby, rigidity in a lengthwise direction L is reduced so as to deform easily, and when a flat cable is used for the connection of a liquid crystal display panel and a circuit board, stress applied to a corner connection portion in vibration is relieved. Insulation resin coated conductors of a single wire or a stranded wire of a circular cross section may be independently formed in the wiring portion 6, or when respective coated conductors are twisted at connection portions between the wiring portion 6 and the terminal portion 4, the flat cable becomes flexible. If a film covering the wiring portion 6 is mounted at a mounting assembling time and is removed later, the assembling work is facilitated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flexible flat cable. More specifically, the present invention relates to a flexible flat cable used for connecting between electronic devices and electronic components, or between electronic components, and the like.

[0002]

2. Description of the Related Art Conventional flexible flat cable F
As C, for example, as shown in FIGS. 9 to 10, the base film 50, a plurality of conductors 51 disposed on the base film 50, and the terminal portions 52 at which both ends of the conductor 51 are exposed are removed. Some include an insulating film 54 coated on the wiring portion 53. The terminal portion 52 in such a flexible flat cable is connected to a board or an electronic component by soldering, an anisotropic conductive film (Anisotoropy Conductive Film, hereinafter referred to as ACF) or a connector.

For example, as shown in FIGS. 11 to 12, in a liquid crystal display device, a liquid crystal display panel 56 fitted into a backlight frame 55 and a circuit board 57 fixed to the backlight frame 55 by screws are connected. In this case, the terminal portion 52 of the flexible flat cable FC is attached to the connection terminal of the panel 56 and the connection terminal of the circuit board 57 by soldering or ACF.

[0004]

In the liquid crystal display device, the liquid crystal display panel is accurately fitted in a backlight frame so that the liquid crystal display panel does not move. However, in a liquid crystal display panel, since liquid crystal and TFT are sealed between a pair of glass substrates, it is necessary to prevent deformation due to pressure. For this reason, a minimum gap is provided between the panel and the backlight frame. Therefore, the panel may be 0.2 to 0.5 m thick due to vibration generated when the liquid crystal display device is carried.
Repeat the movement of about m. When such a panel vibrates in the X direction and the Y direction shown in FIG. 11, the flexible flat cable has high rigidity in the vertical direction (X, Y directions), so that the flexible flat cable is pulled to the corners A, B, C, and D of the cable, respectively. , Compression and twist are alternately applied, and the conductor may be disconnected from the end of the cable.

[0005] As a countermeasure against such disconnection, a method of stiffening the liquid crystal display panel and the flexible flat cable with resin or double-sided tape can be considered. However, this method has a problem that if it becomes defective after fixing, it cannot be disassembled and repaired.

[0006] In view of the circumstances described above, an object of the present invention is to provide a flexible flat cable that can prevent conductor breakage due to vibration or the like.

[0007]

SUMMARY OF THE INVENTION A flexible flat cable according to the present invention comprises a plurality of conductors disposed on an insulating resin, the terminals being exposed so that they can be connected by soldering or the like; A flexible flat cable partitioned into a wiring portion covered with an insulating resin film connecting the portions, wherein a stress relaxation means is provided in the wiring portion.

[0008] The flexible flat cable according to the present invention is characterized in that a plurality of conductors arranged on an insulating resin are exposed so that they can be connected by soldering or the like, and the terminal portions at both ends are connected to each other by an insulation connecting the terminal portions. A flexible flat cable partitioned into a wiring portion covered with a resin film,
It is characterized in that the conductors in the wiring portion are each independently formed as a coated conductor coated with an insulating resin.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A flexible flat cable according to the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a partially enlarged plan view showing an embodiment of a flexible flat cable according to the present invention, and FIG.
And FIG. 3 is a partially enlarged plan view showing another embodiment of the flexible flat cable according to the present invention, and FIG.
7 is a sectional view taken along the line II in FIG. 3, FIG. 5 is a partially enlarged plan view showing still another embodiment of the flexible flat cable of the present invention, FIG. 6 is a sectional view taken along the line II-II in FIG.
7 is a partially enlarged plan view showing still another embodiment of the flexible flat cable of the present invention, and FIG. 8 is a sectional view taken along the line III-III in FIG.

As shown in FIG. 1, a flexible flat cable FC1 comprises an insulating resin 1 as a base film,
Both ends 3 of a plurality of conductors 2 arranged on the insulating resin 1
Is composed of a terminal portion (terminal pattern) 4 exposed so as to be connected by soldering, ACF or a connector, and a wiring portion (wiring pattern) 6 covered with an insulating resin film 5 connecting the terminal portions 4. I have. That is, the plurality of conductors 2 are divided into the terminal portions 4 and the wiring portions 6.

The wiring portion 6 is provided with a stress relaxation means for reducing the rigidity in the longitudinal direction L and making it easy to deform. In the present embodiment, a slit 7 formed between the conductors 2 is used along the substantially entire length of the wiring portion as a notch portion serving as such a stress relaxation means. The invention is not limited to this, and for example, a plurality of through holes may be formed.

As the material of the insulating resin 1 and the insulating resin film 5, for example, a polyimide resin having heat resistance and insulating properties can be used.

The flexible flat cable FC1 according to the present embodiment is used for connecting a liquid crystal display panel 8 and a circuit board 9 in a liquid crystal display device, for example, as shown in FIG. Reference numeral 10 denotes a backlight frame in which the liquid crystal display panel 8 and the circuit board 9 are incorporated. The liquid crystal display panel 8 and the flexible flat cable FC
1 and the circuit board 9 and the flexible flat cable FC1 are respectively attached via ACF.

In such a liquid crystal display device, since the circuit board 9 is fixed to the backlight frame 10, when the liquid crystal display panel 8 vibrates in the vertical direction (X, Y directions) parallel to the circuit board 9, a flexible flat panel is formed. Cable FC
The corner connections A, B, C, and D of each of the connection portions 1 are subjected to a force to shear the corner connections A, B, C, and D. When a force is applied to the liquid crystal display panel 8 in the rotational direction with the circuit board 9 as a fulcrum due to the vibration, a tensile force and a compressive force act on the corner connection portions A, B, C and D, respectively.

However, since the slit 7 is formed in the wiring section 6 of the flexible flat cable F1 of the present embodiment, the wiring section 6 is easily deformed, and the corner connecting sections A, B, C, and D are formed. The acting stress is reduced. For this reason, the corner connection portions A, B, C, and D are not disconnected, and there is no disconnection.

Next, another embodiment of the present invention will be described. In the present embodiment, as shown in FIGS. 3 and 4, the insulating resin between the conductors 12 in the wiring portion 11 of the flexible flat cable FC2 is omitted, and the conductors 12 are each formed into a coated conductor 14 independently coated with the insulating resin 13. ing. That is, in the present embodiment, the slit is greatly widened, the periphery of the conductor 12 is made only of the film of the insulating resin 13, the rigidity of the flexible flat cable FC2 is further reduced as compared with the above-described embodiment, and the corner connection portion A , B, C and D
The stress acting on the ACF (see FIG. 2) is reduced.

Next, still another embodiment of the present invention will be described. In the present embodiment, as shown in FIGS. 5 and 6, at least the connecting portion 16 between the wiring portion 11 and the terminal portion 15 is connected to the covering conductor 14 in the present embodiment by 90 °, for example.
It twists to give flexibility to external forces.

Next, still another embodiment of the present invention will be described. In the present embodiment, as shown in FIGS.
Instead of the coated conductor 14 in the present embodiment, a coated conductor 18 in which a single wire of a conductor 17 having a circular cross section is coated with an insulating resin 18 is used. In the present invention,
However, the present invention is not limited to this. Instead of the single wire, a conductor can be used as a stranded wire. Since the cross-sectional area of the connecting portion is reduced by such a single wire or a stranded wire,
Flexibility is improved as compared with the flexible flat cable in the embodiment.

Since the flexible flat cable according to the embodiment shown in FIGS. 3 to 8 is difficult to assemble during mounting, a film corresponding to a base film is temporarily attached so as to cover the wiring portion. Can be removed to facilitate the work.

[0021]

As described above, according to the present invention,
Since the stress acting on the terminals is reduced, the ACF
And the corner connection portion of the soldered terminal portion of the fine terminal does not come off due to an external force due to vibration or the like, thereby causing a disconnection. Therefore, the vibration resistance of an electronic device such as a liquid crystal display device can be improved.

[Brief description of the drawings]

FIG. 1 is a partially enlarged plan view showing an embodiment of a flexible flat cable according to the present invention.

FIG. 2 is an explanatory diagram in which the flexible flat cable in FIG. 1 is used for a liquid crystal display device.

FIG. 3 is a partially enlarged plan view showing another embodiment of the flexible flat cable of the present invention.

FIG. 4 is a sectional view taken along a line II in FIG. 3;

FIG. 5 is a partially enlarged plan view showing still another embodiment of the flexible flat cable of the present invention.

FIG. 6 is a sectional view taken along line II-II in FIG.

FIG. 7 is a partially enlarged plan view showing still another embodiment of the flexible flat cable of the present invention.

8 is a sectional view taken along the line III-III in FIG.

FIG. 9 is a partially enlarged plan view showing an example of a conventional flexible flat cable.

FIG. 10 is a front view of the flexible flat cable in FIG. 9;

FIG. 11 is a plan view showing an example of a conventional liquid crystal display device.

12 is a cross-sectional view of the liquid crystal display device shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Insulating resin 2 Conductor 3 Both ends 4 Terminal part 5 Insulating resin film 6 Wiring part 7 Slit 8 Liquid crystal display panel 14, 19 Coated conductor FC1, FC2 Flexible flat cable, FC3

Claims (8)

[Claims] 1. A terminal part at both ends, and a wiring part covered with an insulating resin film connecting the terminal parts, wherein a plurality of conductors arranged on the insulating resin are exposed so as to be connected by soldering or the like. A flexible flat cable, wherein the wiring portion is provided with a stress relaxation means. 2. The flexible flat cable according to claim 1, wherein said stress relaxation means is a notch formed between conductors in said wiring portion. 3. The flexible flat cable according to claim 2, wherein the notch is a slit. 4. A plurality of conductors disposed on an insulating resin are exposed so as to be connected by soldering or the like, and terminal portions at both ends and a wiring portion covered with an insulating resin film connecting the terminal portions are provided. A flexible flat cable, wherein the conductors in the wiring portion are each independently formed into a coated conductor coated with an insulating resin. 5. The flexible flat cable according to claim 4, wherein the covered conductor is twisted at least at a connecting portion between the wiring portion and the terminal portion. 6. The flexible flat cable according to claim 4, wherein the coated conductor is formed by coating a single wire of the conductor with an insulating resin. 7. The flexible flat cable according to claim 4, wherein the covered conductor is formed by covering a stranded wire of the conductor with an insulating resin. 8. The flexible flat cable according to claim 4, wherein a film covering the wiring portion is mounted.