JPS63164395A - Printed wiring board - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a printed wiring board used when mechanical electronic components are primarily fixed to a board by bending lead terminals of electronic components and then soldered.

Conventional technology A conventional printed wiring board will be explained using FIGS. 3 and 4.

FIG. 3 is a mounting view of a conventional printed wiring board in which electronic components are mounted and the lead terminals of the electronic components are bent and temporarily fixed, that is, soldering is performed from the previous soldering surface. 1 is a lead terminal of an electronic component, and 2 is a conductive foil printed and wired on a board, and is covered with a solder resist except for the shaded area. Also, the character and symbol 3 (thick line in this example) is a service map. FIG. 4 is a cross-sectional view of the mounted printed wiring board shown in FIG. 3 after soldering, and the same parts as in FIG. 3 are given the same numbers. 4 is a substrate, and 6 is a solder resist. The shaded area 6 is solder.

According to such a configuration, when the lead terminal 1 and solder 6 of an electronic component exist on a conductive foil with different potentials as shown in FIG. 4, electrical insulation can be maintained with only one layer of very thin solder resist 6. ing. Furthermore, in today's world where high-density electronic components are required to be mounted, the number of such locations has increased significantly.

Problems to be Solved by the Invention In the above configuration, reliability of the solder resist 6 is extremely required, but the thickness of the solder resist 6 is approximately 1
Because it is extremely thin, at around 0 μm, electrical insulation may not be maintained due to pinholes or scratches caused by mechanical shock. It is also conceivable that scratches may occur due to contraction or expansion of the substrate itself. That is, as high-density packaging is required, the lead terminals 1 or solder 6 of electronic components often exist on conductive foils at different potentials, so insulation defects in these parts increase significantly. This has become a major technical challenge for high-density packaging. In addition, when electronic components are automatically mounted on a printed wiring board using an automatic machine, the length of the lead terminal 1 is unique to the automatic machine, and the number of tubes is very large, so after automatic mounting, It is virtually impossible to reliably cut the lead terminal 1 so that it does not exist on a conductor foil having a different potential.

Therefore, the present invention provides a printed wiring board that is more reliable when mounting electronic components by actively using the coating film of the service map to electrically insulate the lead terminals and the conductive foil at a different potential. .

Means for Solving the Problems The technical means of the present invention for solving the above problems is that the soldering lead terminals 10 of electronic components have a length equal to or longer than the length of the bent portion of the lead terminals 1 in the direction of bending the surface. This is a double registration using service map 3 for areas larger than the length and width.

action The effect of this technical means is as follows.

In other words, when soldering a lead terminal of an electronic component, double register the length and width of the lead terminal in the bending direction of the surface with a service map, so that the lead terminal has a conductive potential different from that of the lead terminal. A double structure of solder resist and service map is used to electrically insulate between the body foils, which greatly reduces defects caused by pinholes and scratches, and improves the performance of printed wiring boards under high-density mounting. Reliability can be greatly improved without increasing man-hours.

Embodiment FIG. 1 shows an embodiment of the printed wiring board of the present invention. The soldering is from the front soldering side, and FIG. FIG.

Parts that are the same as those in FIGS. 3 and 4 are given the same numbers. In FIGS. 1 and 2, 3' is a double resist based on a service map, and in this example, there are four locations in each of FIGS. 1 and 2, which are shown filled in.

That is, this filled-in area forms a double electrically insulating layer with the solder resist 6 and the service maps 3 and 3'.

That is, by adopting such a configuration, even when the lead terminal 1 and the solder 6 of the electronic component are present on the conductive foil at different potentials, the solder resist 6 and the service map 3'
This results in a double insulating layer, which provides better electrical insulation against scratches caused by pinholes, mechanical shock, etc., and scratches caused by contraction and expansion of the board 2 itself, compared to the case where only one layer of solder resist 5 is used. can have very high reliability.

Furthermore, since the second electrically insulating layer is formed using the service map 3', a highly reliable printed wiring board can be provided without increasing the number of man-hours.

In addition, a service map 3' which is a second electrically insulating layer is provided.
The shape may be any shape as long as it covers the projected shape of the lead terminal 10 of the electronic component onto the substrate.

Effects of the Invention As described above, soldering of lead terminals of electronic components is achieved by double-registering the length and width of the lead terminal in the bending direction with a service map on the bending part of the surface. Even during high-density mounting, where the lead terminals or solder of electronic components often exist on conductive foils with different potentials, the double electrical insulating layer of solder resist and service map prevents electrical damage caused by pinholes and scratches. The present invention provides a highly reliable printed wiring board under high-density packaging without increasing the number of man-hours since insulation defects are prevented and the second electrical insulating layer is formed using a service map.

[Brief explanation of the drawing]

Figure 1 is a plan view of the soldering of the printed wiring board according to an embodiment of the present invention from the previous soldering surface, and Figure 2 is a plan view of the soldering of the printed wiring board mounted in Figure 1. Figure 3 shows an example of a conventional printed wiring board. Figure 4 is a plan view of the mounted state from the previous soldering surface. Figure 4 is the printed wiring mounted in Figure 3. The soldering of the plate is a cross-sectional view of the later Mu people. 1... Lead terminal for electronic components, 2...
Conductive foil, 3.3'...Service map, 4.
... Board, 5 ... Solder resist. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2

Claims (1)

[Claims] A lead for an electronic component placed on the board includes a conductive foil printed with wiring on a board, a solder resist placed on the conductive foil, and a service map placed on the solder resist. A printed wiring board in which a service map is double-registered on a bent portion of a soldering surface of a terminal with a length and width greater than or equal to the length of the bent portion of the lead terminal in the bending direction.