JPS587658Y2 - printed circuit board - Google Patents

Description

[Detailed Description of the Invention] This invention relates to continuity testing of printed circuit boards.

Conventionally, continuity testing of printed circuit boards has been performed using a continuity testing machine whose prober pitch dimension matches the grid pitch dimension of the printed circuit board.

Therefore, for printed circuit boards with different grid pitches, it was necessary to prepare testing machines whose dimensions matched the dimensions. The disadvantage was that equipment costs increased.

This idea was made to overcome the above-mentioned drawbacks, and it is a printed circuit that has been devised so that continuity testing can be performed using the same continuity testing machine even for printed circuit boards with different grid pitches. The purpose is to provide substrates.

The key point of the invention is that by arranging multiple types of pads with different shapes on a printed circuit board, it is possible to test printed circuit boards with different grid pitches using the same continuity tester. .

This invention will be explained in detail below with reference to the drawings.

FIG. 1 shows a component mounting surface of a conventional printed circuit board.

In FIG. 1, 1 is a printed circuit board, 2 is a testable pad, 3 is a non-testable pad, 4 is a component mounting pad, and 5 is a pattern.

As shown in FIG. 1, among the pads on the printed circuit board 1, there are pads 2 that can be tested for continuity and pads 3 that cannot be tested. Pad 2 that can be tested for continuity using pattern 5
Bring it out and have it inspected.

Now, pad 2 that can be inspected and pad 3 that cannot be inspected.
The reason why this occurs is as follows.

If the grid pitch of the printed circuit board 1 is, for example, the pitch of the prober of a 75ml continuity tester 100 mils, then within the least common multiple of 300 mils, there will be 4 grids on the printed circuit board and 3 probers with 3 pitches, so that the pitch of the probers in the vertical and horizontal directions will be 4. One out of every four rows is a pad 3 that cannot be tested for continuity.

Generally, it is calculated as follows. Number of probers / number of printed circuit board grids = (prober pitch) 2 / (grid pitch) 2 In the current example, since the prober has 3 pitches and the grid has 4 pitches, 32/42 = 9/16, and 16 Nine of the pads can be tested, and the remaining seven pads cannot be tested.

FIG. 2 is a diagram showing the shape and arrangement of pads on the back surface of the printed circuit board 1 on which continuity testing is performed, and is a diagram showing an embodiment of this invention.

In FIG. 2, 101 is a circular pad, 102 is a through hole, and 103 is an oval pad.

In FIG. 2, the printed circuit board 1, -1=-, and the circular pads 101 are placed at the positions that match the pitch of the blow μ.

Where continuity testing is required even though the pitch does not match the low μ pitch, use a length of 25 mil (100-75 ml) in the vertical or horizontal direction, or J7 x 25 mil in the 45° direction, using the through hole 103 as a reference. Arrange the elliptical pad 102 so that it matches the pitch of the blow μ.

In areas where the pitch of the blow μ does not match and where continuity testing is not required, circular pads are placed for through holes for printed wiring.

FIG. 3 is a sectional view of the printed circuit board taken along lines A and A' in FIG. 2, showing a state in which the blow μ of the continuity tester is connected.

201 indicates blow μ. As can be seen from FIG. 3, the circular pad 101 is connected to the through hole 102 at the circular pad 101 that matches the pitch of the blow μ, and the blow μ 201 is connected to the oval portion of the oval pad 103 for continuity testing. It will be done.

The component mounting pad 4 explained in FIG. 1 is a circular pad (for example, 101) that can be inspected because it matches the pitch of the blow μ.
In addition, even pads (for example, 103) that do not match the pitch of the blow μ but can be inspected because the blow μ can be connected due to the placement of elliptical pads (for example, 103) need to be drawn out using pattern 5. .

As described above, according to this invention, by arranging, for example, an oval pad on a printed circuit board, continuity testing becomes possible even with a continuity testing machine that has a blow μ with a pitch that does not match the grid pitch of the printed circuit board. , This idea has great practical and economic value.

[Brief explanation of drawings]

FIG. 1 shows a component mounting surface of a conventional printed circuit board. FIG. 2 is a diagram showing an embodiment of this invention, showing the shape and arrangement of pads on the back side of a printed circuit board. FIG. 3 is a sectional view of the printed circuit board taken along lines A and A' in FIG. 2, showing a state in which the blow μ of the continuity tester is connected. In the figure, 1 is a printed circuit board, 2 is a pad that can be inspected, 3 is a pad that cannot be inspected, 4 is a pad for mounting components, 5 is a pattern, 101 is a circular pad, 102 is a through hole, 103 is an oval pad, 201 indicates blow μ.

Claims (1)

[Scope of utility model registration request] A printed circuit board in which multiple types of pads with different shapes are arranged in through holes, and the various types of pads described above can be tested even by a continuity tester having a prober with a pitch different from the grid pitch of the through holes. A printed circuit board characterized by having pads having a defined shape.