JPH03232296A - Printed board solder resist - Google Patents

Abstract

PURPOSE:To improve a pattern in electrical insulation properties by a method wherein ceramic particles are mixed into the solvent of solder resist, and the solder resist is applied overlapping the edge of the pad of a pattern on a wiring board exposed to air. CONSTITUTION:A large number of copper patterns 14 are provided onto the upside of a printed board 13, and a solder resist 15 of high molecular resin is applied onto a space between the copper patterns 14 overlapping the edge of a pad 14a of the pattern 14 which is exposed to air and electronic components are mounted on. Ceramic particles high in electrical insulation properties and breakdown strength are mixed into solvent such as epoxy resin or the like to constitute the solder resist 14. The edge of the pad 14a where a discharge is liable to occur is wrapped with the solder resist 15, and a creeping discharge occurs as conducted along the surface of the complicated ceramic particles of the solder resist 15, so that an insulation creeping distance is substantially elongated, in result the pattern 14 can be improved in electrical insulation properties such as breakdown strength or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a solder resist that can improve the electrical insulation performance of a pattern in a printed circuit board.

[Conventional technology]

A conventional example of a solder resist for a printed circuit board will be explained based on FIG. 4. In this figure, a copper pattern 4 of a printed circuit board 3 is integrally provided on the upper surface of a metal plate 1 via an insulating plate 2, and the remaining surface of the insulating plate 2 is made of polymer resin to prevent adhesion of solder. A solder resist 5 consisting of the pattern 4 is applied with a gap between the solder resist 5 and the pattern 4.

[Problem to be solved by the invention]

In this structure, in order to ensure electrical insulation performance such as withstand voltage strength between the edges of adjacent patterns 4, the higher the working voltage is, the larger the insulation creepage distance between the edges must be. It had the disadvantage of being formalized.

SUMMARY OF THE INVENTION In order to eliminate the above-mentioned drawbacks, it is an object of the present invention to provide a solder resist for a printed circuit board that can improve the electrical insulation performance of a pattern.

[Means to solve the problem]

In order to achieve the above-mentioned object, the present invention mixes ceramic particles having electrical insulation performance and high pressure resistance into the solvent of the solder resist 15 made of polymer resin, and also mixes the ceramic particles in the pattern of the printed circuit board 13. The coating is applied so as to overlap the edge of the pad portion 14a exposed to the air.

[Effect]

The edge of the pad portion 14a where electrical discharge is likely to occur is wrapped in the solder resist 15, and creeping discharge occurs along the intricately intricate surface of the ceramic particles of the solder resist 15, so that the insulation creepage distance is substantially increased and the pressure resistance is improved. The electrical insulation performance can be improved.

〔Example〕

1 to 3 show embodiments of this invention,
Components designated by the same reference numerals as in FIG. 4 are the same parts. In these figures, a large number of copper patterns 14 are integrally provided on the upper surface of a printed circuit board 13, and between adjacent patterns 14, a solder resist 15 made of polymer resin is exposed in the air between the patterns 14 and conducts electrons. Puff part 1 for mounting parts
It is applied to overlap the edges of 4a. The solder resist 15 is made by mixing particles of ceramic having electrical insulation performance and high pressure resistance in a solvent such as epoxy. The pad portion 14a is made larger than that described in the conventional example by the amount of overlap of the solder resist 15.

According to the embodiment, the pad portion 14a where discharge is likely to occur
The edge of the pattern 14 is wrapped in the solder resist 15, and the creeping discharge occurs along the surface of the ceramic particles of the solder resist 15, which are intricately intricate. Therefore, the insulation creepage distance is substantially increased, and the electrical insulation such as the voltage resistance of the pattern 14 is improved. Performance can be improved. Note that the solder resist 1
It has been confirmed that the insulation performance of the pattern 14 can be improved as the coating thickness increases.

〔Effect of the invention〕

According to this invention, in the solder resist for printed circuit boards, ceramic particles are mixed into the solvent of the solder resist made of polymer resin, and the mixture is applied so as to overlap the edges of the pads exposed in the air of the pattern. As a result, it is possible to improve the electrical insulation performance of the pattern and to downsize the printed circuit board.

[Brief explanation of drawings]

FIG. 1 is a front view of an embodiment of the present invention, FIG. 2 is a vertical sectional view taken along line nn in FIG. 1, FIG. 3 is an enlarged longitudinal sectional view of the main part of FIG. FIG. 2 is a vertical cross-sectional view of a main part of a conventional example. 13... Printed circuit board, 14... Pattern, 14a
... Pad part, 15... Solder resist. Figure Figure Figure Figure

Claims (1)

[Claims] 1) In a polymer resin solder resist that is applied between adjacent patterns on a printed circuit board to prevent solder adhesion, ceramic particles that have electrical insulation performance and high pressure resistance are mixed into the resin solvent. and a solder resist for a printed circuit board, characterized in that the solder resist is applied so as to overlap an edge of a pad portion exposed to air of the pattern.