JP2002157920A - Flexible printed circuit harness - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an FPC harness capable of reducing a manufacturing cost. SOLUTION: This FPC harness 1 is composed of a base film 2 using PET or the like as a base material, conductive patterns 3-7 formed on the base film 2, and connection terminals 8 and 9 connected to both end parts of the conductive patterns 3-7. The conductive pattern 3 is connected to a large current circuit, and comprises a upper conductive pattern formed on one surface of the base film 2 and a lower conductive pattern formed on the other surface thereof, and the upper conductive pattern and the lower conductive pattern are formed by being overlapped so as to interpose the base film 2. The conductive patterns 4-7 are respectively connected to a small current circuit and each formed on one surface of the base film 2. The conductive patterns 4-7 are alternately disposed on both the surfaces of the base film 2 in a zigzag form so as not to be overlapped by interposing the base film 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a flexible printed circuit (FPC) harness.

[0002]

2. Description of the Related Art In an automobile harness or the like, an FPC harness using a lightweight FPC has been used in place of a heavy wire harness due to a demand for digitization and weight reduction. FIG. 5 is a plan view of a conventional FPC harness, and FIG. 6 is a cross-sectional view showing a state cut along line VI-VI in FIG. As shown in FIG. 5 and FIG.
The C harness 101 is provided on one side of the base film 102.
Using a copper foil laminated film or the like obtained by laminating copper foil, the conductive patterns 103 to
What formed 107 is used. This conductive pattern 1
Connection terminals (not shown) are connected to both ends of 03 to 107 by welding or the like, and are connected to a connector or the like on the vehicle-mounted module.

[0003] Such an FPC harness 101 is designed such that its conductor width and thickness are optimal values according to the magnitude of the current flowing through the conductive pattern. For example, as shown in FIGS. 5 and 6, the conductive pattern 103 connected to the large current circuit is formed to be wide, and the conductive patterns 104 to 107 connected to the small current circuit are formed to be narrow. Further, the thickness of the copper foil needs to have a sufficient margin in consideration of a conductive pattern to be connected to a large current circuit. At present, a single-sided FPC having a copper foil thickness of 75 μm or more is used.

[0004]

However, in the above-described single-sided FPC having a copper foil thickness of 75 μm or more, the lead time for etching for forming a conductive pattern is long, which is
This is a major factor in raising the manufacturing cost of PCs.

[0005] The present invention has been made in consideration of the above circumstances, and has as its object to provide an FPC harness that can reduce manufacturing costs.

[0006]

An FPC harness according to the present invention comprises a harness main body in which conductive patterns are formed on both sides of a base film, and a conductive pattern which is opposed to the harness main body through the base film. And a first connection terminal connected to a first external circuit.

According to the present invention, the conductive patterns connected to the large current circuit are formed separately on both sides of the base film, and the conductive patterns on both sides are connected at the ends by the connection terminals, so that a current is applied to both conductive patterns. Since the structure is made to flow, the thickness of the conductive pattern can be reduced to half as compared with the case where the conductive pattern forming the large current circuit is formed on one surface of the base film. For this reason, the lead time of etching, which is a circuit forming step, can be reduced to half of the conventional case, and the manufacturing cost can be significantly reduced.

When one harness is connected to a large current circuit and a small current circuit, the harness is connected to a conductive pattern formed on one surface of the base film of the harness main body at an end, and A second connection terminal connected to a second external circuit having a current capacity smaller than that of the first external circuit may be further provided. In this case, it is preferable that a plurality of conductive patterns connected to the second connection terminals are alternately formed on both surfaces of the base film so as not to overlap with the base film interposed therebetween. With such a staggered arrangement, the second connection terminals for small current can be arranged without interfering with each other.

The harness body may be formed by forming the conductive pattern on a copper foil laminated film by etching, or may be formed by plating copper on both sides of the base film and then forming the conductive pattern by etching. Can be used. In particular, in the latter case, since the thickness of the conductive pattern can be reduced, the plating time can be reduced, and the total cost reduction effect is further enhanced.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a plan view of an FPC harness according to an embodiment of the present invention, FIG. 2 is a cross-sectional view showing a state cut along line II-II in FIG. 1, and FIG. 3 is a state cut along line III-III in FIG. A sectional view showing the
FIG. 4 is a sectional view showing a state cut along the line IV-IV in FIG.

As shown in FIGS. 1 and 2, the FPC harness 1 comprises a base film 2 made of polyethylene terephthalate (PET) or the like, and copper foil conductive patterns 3 to 7 formed on both sides of the base film 2. It is composed of a harness main body and connection terminals 8 and 9 connected to both ends of the conductive patterns 3 to 7. FPC harness 1
Is formed by etching a copper foil laminated film in which copper foil having a thickness of 35 μm is attached to both sides of a base film 2 with an adhesive to form conductive patterns 3 to 7 having a predetermined pattern.

The conductive pattern 3 is a conductive portion to be connected to a large current circuit (first external circuit).
And an upper conductive pattern 3a formed on the lower surface and a lower conductive pattern 3b formed on the lower surface. The upper conductive pattern 3a and the lower conductive pattern 3b are formed so as to sandwich the base film 2 therebetween. . On the other hand, the conductive patterns 4 to 7 are conductive portions connected to a small current circuit (second external circuit), and are staggered on both sides of the base film 2 so as not to overlap with the base film 2 therebetween. ing. In this embodiment, the conductive patterns 103 to 1 of the conventional FPC harness 101 shown in FIGS.
The width of the conductive patterns 4 to 7 is twice as large as that of the conductive patterns 4 to 7 because the thickness of the conductive patterns 4 to 7 is reduced to half.

The connection terminal 8 is a member for electrically connecting a connected member such as a connector connected to a large current circuit to both ends of the upper conductive pattern 3a and the lower conductive pattern 3b, and is shown in FIG. As seen from the side, the base end is divided into upper and lower forks to form connection pieces 8a and 8b, and the appearance as viewed from the side is a substantially Y-shaped terminal formed on one surface side of the base film 2. The connection piece 8a is connected to the upper conductive pattern 3a, and the connection piece 8b is connected to the lower conductive pattern 3b formed on the other surface side. The connection terminal 9 is a member for electrically connecting a connected member such as a connector connected to the small current circuit and both ends of the conductive patterns 4 to 7, and is formed on one surface side of the base film 2. The connection pieces 9a are connected to the patterns 4 to 7. Upper conductive pattern 3
When the connection terminal 8 is fixed to the upper conductive pattern 3a and the lower conductive pattern 3b, when the connection terminal 8 is fixed to the lower conductive pattern 3b, The electrodes may be fixed by series welding in which a pair of electrodes (not shown) are brought into contact with each other at predetermined intervals in the direction of the arrow in FIG. When the connection terminals 9 are fixed to the conductive patterns 4 to 7, they can be fixed by the same method. Note that the tips of the connection terminals 8 and 9 are
In order to couple with a mating connector, it is desirable to have a common shape.

The present invention is not limited to the embodiment described above, and various modifications or changes are possible. For example, in the above embodiment, the substantially L-shaped connection terminal 9 is connected to the conductive patterns 4 to 7 constituting the small current circuit.
A substantially Y-shaped connection terminal 8 connected to the conductive pattern 3 connected to the large current circuit may be connected to the conductive patterns 4 to 7. In this case, one of the connection pieces 8a and 8b may be connected to the conductive patterns 4 to 7. Alternatively, the FPC harness may be formed by subjecting the base film to electroless plating and then electrolytic copper plating.

[0015]

As described above, according to the present invention, the conductive patterns to be connected to the large current circuit are formed separately on both sides of the base film, and the conductive patterns on both sides are connected at the ends by the connection terminals. Since the current flows through both conductive patterns, the thickness of the conductive pattern forming the large current circuit can be reduced to half the thickness when formed on one surface of the base film. For this reason, the lead time for etching, which is a circuit forming step, can be reduced to half of the conventional case, and the manufacturing cost can be significantly reduced.

[Brief description of the drawings]

FIG. 1 is a plan view of an FPC harness according to one embodiment of the present invention.

FIG. 2 is a sectional view showing a state cut along a line II-II in FIG. 1;

FIG. 3 is a cross-sectional view showing a state cut along a line III-III in FIG. 1;

FIG. 4 is a sectional view showing a state cut along the line IV-IV in FIG. 1;

FIG. 5 is a plan view of a conventional FPC harness.

FIG. 6 is a cross-sectional view showing a state cut along a line VI-VI in FIG. 5;

[Explanation of symbols]

1,101: Flexible printed circuit (FPC) harness, 2,102: Base film, 3-7, 103-
107: conductive pattern, 3a: upper conductive pattern, 3b
... lower conductive pattern, 8, 9, 108 ... connection terminals.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H05K 1/11 H05K 1/11 F H01R 9/09 D (72) Inventor Kazuya Akashi 1440 Mutsuzaki, Sakura City, Chiba Prefecture Address Fujikura Sakura Works Co., Ltd. F-term (reference) 5G311 CA02 CB01 CC02 CD10 CF04

Claims (6)

[Claims] 1. A harness main body having conductive patterns formed on both sides of a base film, and the conductive patterns facing each other via the base film of the harness main body are connected at their ends, and are connected to a first external circuit. A flexible printed circuit harness, comprising: a first connection terminal to be connected. 2. An end connected to a conductive pattern formed on one surface of the base film of the harness main body, and connected to a second external circuit having a current capacity smaller than that of the first external circuit. 2. The flexible printed circuit harness according to claim 1, further comprising a second connection terminal. 3. A plurality of conductive patterns to which the second connection terminals are connected are formed alternately on both surfaces of the base film so as not to overlap with the base film therebetween. 2. The flexible printed circuit harness according to 2. 4. The flexible printed circuit harness according to claim 1, wherein the conductive pattern has a thickness of 35 μm or less. 5. The flexible printed circuit harness according to claim 1, wherein the harness main body is formed by forming the conductive pattern on a copper foil laminated film by etching. 6. The harness main body according to claim 1, wherein the conductive pattern is formed by etching after plating copper on both surfaces of the base film. Flexible printed circuit harness.