JPH0497589A - Printed wiring board - Google Patents

Abstract

PURPOSE:To do wiring and pattern cutting at the rear of a board without lowering the density in mounting of parts by providing copper foil pads for wiring and through-holes for wiring via through-holes for wiring to copper foil pads for mounting. CONSTITUTION:A through-hole 2 for wiring is connected to every copper foil pad 1 for parts mounting at the surface of a substrate, and a through-hole 3 for wiring is provided corresponding to it. Moreover, at the rear of the substrate, the through-hole 2 for wiring is provided with a copper foil pad 4 for wiring, and it is connected to the through-hole 3 for wiring by a pattern for cutting 5. For the signal wiring of the inner layer, it is wired using the through- hole 3 for wiring alone. For cutting, the connection between an inner layer wiring pattern 9 and an IC is broken by removing the pattern 5 for cutting, and for wiring, the connection with the IC 10 is performed by soldering a line material 6 to the copper pad 4 for wiring by solder 7.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a printed wiring board, and particularly to the structure of a printed wiring board on which mounted components are mounted.

[Conventional technology]

Conventionally, as shown in FIGS. 5 and 6, this type of printed wiring board only has component mounting copper foil pads 11 on the surface of the board for mounting component pins (FIG. 5);
Alternatively, the substrate has a structure in which a copper foil pad 12 for wiring and a cutting pattern 13 are further provided on the surface of the board (FIG. 6).

[Problem to be solved by the invention]

In recent years, with the development of device technology, components have become more compact, and the pin diameter and pin spacing of component pins have continued to shrink. Along with this, mounting technology to effectively utilize these components has also improved, and printed wiring has become more compact. As for mounting on substrates, high-density mounting and surface mounting are progressing.

If a surface mounting method is adopted, all wiring and pattern cutting due to logic changes etc. will be processed on the component mounting surface. In pattern cutting work, the cutting point may be under the component, which creates extra work to attach and remove the component, and wiring work requires soldering directly to the component pin, but the pin diameter and pin spacing may be Because they are small, soldering tends to be incomplete and defects such as shorts between adjacent pins occur. In order to prevent defects when attaching, removing, and soldering these parts, there is a method of lifting a parts bin above the printed wiring board and wiring it to the bin, but the bottle tends to break when it is lifted, and Because it remains floating, it is vulnerable to shocks and poses a problem in terms of reliability.

On the other hand, if copper foil pads for wiring and cutting patterns are provided on the printed wiring board, the area occupied by the components will increase, leading to a decrease in component mounting density, and there are disadvantages such as eliminating the effectiveness of adopting the surface mount method. .

[Means to solve the problem]

The present invention provides a surface mount type printed wiring board, in which each mounted component bin has a first through hole having a copper foil pad on the front surface and the back surface of the board, and is connected to the first through hole on the back surface by a pattern. and a second through hole.

Further, in the printed wiring board of the present invention, the pattern can be cut.

〔Example〕 Next, the present invention will be explained with reference to the drawings.

Figures 1 and 2 are a plan view of an embodiment of the present invention as seen from the front side and a plane view of the back side, and Figures 3 and 4 are views of this embodiment after cutting and wiring. FIG. 2 is a plan view and a sectional view seen from the back side.

This embodiment has a wiring through hole 2 having a component mounting copper foil pad 1 and a wiring copper foil pad 4 on the front and back sides of the board for each mounted component pin, and a wiring through hole 2 on the back side of the board. It has a wiring through hole 3 connected to the hole 2 by a cutting pattern 5.

That is, a through hole 2 for wiring is connected to each copper foil pad 1 for mounting components on the surface of the board, and a through hole 3 for wiring is provided corresponding to the through hole 2 for wiring. Further, on the back side of the substrate, copper foil pads 4 for wiring are provided in the through holes 2 for wiring, and the through holes 3 for wiring are connected by a cutting pattern 5. Here, the signal wiring in the inner layer is wired using three wiring through holes.

In this embodiment, when performing cutting and wiring work, as shown in FIGS. 3 and 4, the cutting is performed by removing the cutting pattern 5 to connect the inner layer wiring pattern 9 and ICl0. If the connection is broken and the wiring is soldered to the wiring copper foil pad 4 with solder 7, ICl0
Both can be processed on the back side of the board rather than on the component mounting side.

〔Effect of the invention〕

As explained above, in the present invention, by providing a copper foil pad for wiring and a through hole for wiring via a through hole for wiring on a copper foil pad for mounting components, the mounting density of components does not decrease. This has the effect that wiring and pattern cutting due to logic changes etc. can be easily done on the back side of the board.

A plan view and a sectional view as seen from the back side, Fig. 5 is a plan view of the component mounting section of a conventional printed wiring board as seen from the front side, and Fig. 6 is a diagram of the case in which copper foil pads for wiring are provided in Fig. 5. FIG.

1.11...Copper foil pad for component mounting, 2...Through hole for wiring, 3...Through hole for wiring, 4゜12
...Copper foil pad for wiring, 5,13...Cutting pattern, 6...Wire, 7...Solder, 8...Printed wiring board, 9...Inner layer wiring pattern, 10.・IC
.

Claims (2)

[Claims] 1. In a surface mount type printed wiring board, a first through hole having a copper foil pad on the front and back surfaces of the board for each mounted component pin, and a second through hole connected to the first through hole in a pattern on the back surface. A printed wiring board characterized by comprising a through hole. 2. The printed wiring board according to claim 1, wherein the pattern is cuttable.