JPS5911458Y2 - printed wiring board - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a printed wiring board, and more particularly to the shape of a circuit pattern at a circuit branch point of a printed wiring board and its connection.

Conventionally, this type of circuit pattern connection has been performed using solder joints, and therefore a circuit pattern having a structure in which a conductor 1 is separated by a gap 2 as shown in FIG. 1 has been formed on an insulating substrate.

Such conventional means are convenient for voltage-controlled electric circuits with high impedance input/output characteristics, but in current-controlled electric circuits with low impedance input/output characteristics, due to changes over time as shown in Figure 2. It has been confirmed from the results of cycle tests and field tests that there is a fatal defect in that the bridge joint portion 3a of the solder material 3 cracks, resulting in disconnection.

This is explained as follows.

First, solder materials commonly used for electronic devices have a resistance value about 10 times higher than that of copper.

Furthermore, as shown in Fig. 2, by soldering, the tin in the precipitate is used to form an alloy layer (hereinafter referred to as alloy layer) 4 of an intermetallic compound between it and the underlying conductor 1, and as a result, the solder material 3
As the lead content increases, the resistivity increases.

Since a current is continuously or intermittently applied to the solder material 3 from the conductor 1, a portion of the current is converted into thermal energy due to the resistance inside the solder material 3, giving stress.

Furthermore, the bridge section deteriorated due to environmental stress.

The purpose of the present invention is to provide a printed wiring board in which the circuit pattern has a unique shape in order to solve the fatal drawbacks of these conventional techniques.

According to the present invention, a notch is provided in a part of the main circuit pattern, and the circuit pattern includes the notch and a land portion that holds and fills the notch in a certain gap. A printed wiring board characterized by this is obtained, and furthermore, a printed wiring board characterized by having the gaps connected by lead wires is also obtained.

In particular, according to the present invention, in a printed wiring board having a circuit pattern in which a second circuit pattern narrower than the first circuit pattern is branched in a direction substantially orthogonal to the first circuit pattern, the first circuit pattern and the second circuit pattern are shaped so that the branch part of the second circuit pattern enters into the first circuit pattern,
A printed wiring board is obtained in which the branch portion of the second circuit pattern has a width wider than the width of the second circuit pattern.

The present invention will be explained below with reference to the drawings.

FIG. 3 shows the structure of one embodiment of the circuit pattern of the printed wiring board of the present invention, where 6 is a main circuit pattern having a notch in a part of the circuit pattern, and 7 is a main circuit pattern that fills the notch of the main circuit pattern 6. The seat 7 is shaped by maintaining a certain gap 8 so that
This is a circuit pattern with a.

FIG. 4 shows a side view in which the gap 8 at the circuit pattern branch point in FIG. 3 is soldered and connected by a joining bus bar (hereinafter abbreviated as lead wire) 9 such as a copper wire.

As described above, by using circuit pattern branching points according to the structure of the present invention, or because connections can be made at multiple locations with more gaps than conventional linear gaps, even if one of the joints breaks, there will still be connections.

The joint is firmly connected and stable by the alloy layer 4, and the electrical resistance can be kept low by the connecting lead wire 9.

Furthermore, FIGS. 5, 6, and 7 show other embodiments of the present invention, and by using the circuit pattern shapes of these branch points, unconnected parts can be easily recognized. There is an advantage that the joining work can be easily performed when the parts are lined up as shown in the figure.

[Brief explanation of the drawing]

Figure 1 shows the circuit pattern of a conventional printed wiring board branch point. FIG. 2 is a sectional view of the solder bridge connection state of FIG. 1. Figure 3 shows the circuit pattern of the printed wiring board branch point of the present invention. FIG. 4 is a sectional view of the connection state shown in FIG. 3; Figures 5 to 7
The figure shows a circuit pattern of another embodiment of the printed wiring board of the present invention. FIG. 8 is a circuit pattern showing an applied example of the printed wiring board branch connection state according to the present invention. In the figure, 1゜゜゜...Conductor, 2, 8...Gap, 3...Solder material, 4...Alloy layer, 5
...Insulating board, 6...Main circuit pattern, 7...Circuit pattern with seat, 7a...
- Seat, 9... Connection bus bar (lead wire).

Claims (2)

[Scope of utility model registration request] (1) A printed wiring board having a circuit pattern in which a second circuit pattern narrower than the first circuit pattern is branched in a direction substantially orthogonal to the first circuit pattern,
A thin separation region where the first circuit pattern and the second circuit pattern are separated is shaped so that a branch part of the second circuit pattern enters into the first circuit pattern, and A printed wiring board characterized in that a branch portion of a circuit pattern has a width wider than the width of the second circuit pattern. (2) A utility model registration request characterized in that the first circuit pattern and the second circuit pattern are electrically connected by a connecting lead wire along the extending direction of the first circuit pattern. A printed wiring board according to scope 1.