JPS6243309B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to the configuration of a wiring board connector, and in particular, connects a flexible wiring board (hereinafter referred to as a double-sided wiring FPC board) having wiring patterns on both sides to a thin film wiring board by soldering. The present invention relates to the configuration of a wiring board connector.

In general, a thin film wiring board is a substrate made of glass, ceramic, etc., with electrodes of 1 μm or less thick formed by vapor deposition, and a double-sided wiring FPC board is a substrate made of polyimide film, polyester film, etc., with conductor wiring patterns on both sides. was formed.

Conventionally, double-sided FPC boards that are connected by soldering to the above-mentioned thin film wiring boards are as shown in Figure 1.
The front surface of the FPC film 1 is formed by a conductor wiring pattern 2 that is not soldered, and this pattern is covered with an overcoat 3 made of resin, etc., while the back surface is a conductor wiring pattern for connecting to a thin film wiring board by soldering. 4 is formed, and a solder layer 5 is partially formed on the pattern by solder plating.

The above double-sided wiring FPC formed in this way
A case in which a substrate is connected to a thin film wiring board by soldering will be explained based on FIG. 2. In the diagram A
is the cross section of the FPC explained in Figure 1, and B is A.
This is a thin film wiring board that is connected by soldering. This substrate is made of glass, ceramic, etc.
For example, a thin film wiring 7 with a thickness of 1 μm or less,
7 is formed by vapor deposition or the like. In such a conventional configuration, a conductor wiring pattern 4 formed on one surface of the FPC 1 and having a solder plating layer 5;
The conductor wiring patterns 2 formed on the other side of the FPC 1 and covered with the overcoat 3 without being subjected to solder plating treatment do not face each other, in other words, the patterns 4 and 2 do not face each other.
They were not provided so that the front and back sides of the FPC1 were aligned with each other.

However, when connecting such an FPC to a thin film wiring board by soldering using a heating and pressurizing device such as the heating head 8, the FPC is
Since a large force is applied to the front pattern 2 of 1, the gap P between the solder layers 5, 5 at the soldering part plated on the back pattern 4 becomes narrower, and the surplus solder 5 is applied to the adjacent thin film wiring board 6. The problem was that the solder started to flow in the direction of the wiring patterns 7, 7, and the solder touched each other due to uneven pressure, which caused the problem of electrical shoot failure.

The present invention was made in order to eliminate the drawbacks of the above-mentioned conventional wiring board connector configuration.
Especially formed on one side of double-sided wiring FPC board,
By forming and arranging a conductor wiring pattern that is not to be soldered on the other side of the FPC board, facing each other to the conductive wiring pattern that is to be soldered, it is possible to prevent solder spots due to uneven pressure. This is what I did.

An embodiment of the present invention will be described below with reference to the drawings. FIG. 4 shows an example of a double-sided wiring FPC according to the present invention, and 1 is a flexible wiring board (FPC) made of polyimide film, polyester film, etc.
Then, on this FPC, front conductor wiring patterns 2', 2'' and back conductor wiring patterns 4', 4'' are formed and arranged so as to face each other, and among these patterns, according to the embodiment, pattern 2' is Pattern 2'' is a necessary pattern on the circuit, and pattern 2'' is an unnecessary pattern on the circuit, and is placed facing the front and back patterns to prevent uneven pressure.In other words, patterns 2'' and 4'' are unnecessary on the circuit. Similarly to the necessary patterns 2' and 4', the pressure applied to the solder plating layers 5 and 5 can be made uniform by appropriately replenishing them and forming and arranging them.The unnecessary patterns are also called pseudo patterns. be able to.

Figure 5 is a cross-sectional view of the FPCA and thin film wiring board B before soldering connection, and Figure 6 is a cross-sectional view of the FPCA and thin film wiring board B before being connected by soldering.
FIG. 3 is a cross-sectional view of the connection between the FPC and the thin film wiring board. In the figure, when a conductor pattern 2' is formed on the other side of the FPC that faces the conductor pattern 4' having the solder plating layer 5 of the FPC 1, and the conductor pattern 2' cannot be made to face each other only with the conductor patterns necessary for the circuit. forms a pseudo pattern and forms other conductive patterns in preparation for pressure adjustment. That is, in the solder plating layer of the FPC, each conductor pattern is formed at the same position on both sides of the FPC.

When formed and arranged as in the present invention, a uniform load is applied to the pattern having the solder plating layer, and the gap between the FPC board and the thin film wiring board, the so-called base board, is uniformly reduced. Therefore, the solder does not flow in the direction of the adjacent wiring, causing no solder touches, and it is possible to eliminate touch defects in board connections and significantly improve reliability.

[Brief explanation of the drawing]

Figure 1 is a partially transparent plan view of a conventional FPC board, Figure 2 is a cross-sectional view of the same FPC board and base board, and Figure 3 is an explanatory diagram of the operation when both of the same boards are connected.
FIG. 4 is a partially transparent plan view of the FPC board according to the present invention, FIG. 5 is a sectional view of the FPC board and the base board, and FIG. 6 is an explanatory diagram of the operation when the two boards are connected. 1: FPC board, 2, 2', 2'': conductor pattern, 4, 4', 4'': conductor pattern with solder plating layer, 5: solder plating layer, 6: base board,
7: Thin film wiring.

Claims (1)

[Claims] 1. A flexible wiring board (hereinafter referred to as double-sided wiring FPC) having conductive wiring patterns on both sides of a thin film wiring board.
It is called a board. ) are connected by soldering, the conductive wiring patterns formed on one side of the above-mentioned double-sided wiring FPC board and solder-plated are opposite to each other, and the other side of the above-mentioned FPC board is A configuration of a wiring board connector characterized by forming and arranging a conductor wiring pattern that is not subjected to solder plating.