JPS61135191A - single-sided 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] [Industrial application field] The present invention relates to improvements in single-sided printed wiring boards.

Single-sided printed wiring boards in which a conductive pattern is formed on only one surface are widely used as the material for the printed circuit board, since the phenolic material is inexpensive.

However, compared to other materials such as glass epoxy materials, it has a high water absorption rate and is inferior in mechanical rigidity, etc., so these points must be kept in mind when using it.

[Conventional technology]

FIG. 3 is a sectional view of a conventional single-sided printed wiring board, and FIG. 4 is a plan view of the component mounting surface side.

In FIG. 3, a conductor pattern 4 is formed on a pattern surface 3, which is one surface (lower surface in FIG. 3) of a printed circuit board 1 made of, for example, a phenol material. On the component mounting surface 2, which is the other surface (the top surface in FIG. 3), the mounted components 5 are mounted by inserting each glue 5a of the mounted components 5 into the corresponding component holes 6. ing.

The tip of this lead 5a faces the pattern surface 3 side,
The parts are dipped in solder and fixedly connected to the respective component lands 12 using solder 7.

Before mounting the mounting component 5, the pattern surface 3 is screen printed to form a solder resist film 8 using a desired mask pattern that does not print the component lands 12. Therefore, the entire surface of the pattern surface 3 including the surface of the conductor pattern 4, except for the component land 12, is coated with the solder resist film 8.

Therefore, in such a conventional single-sided printed wiring board, since the pattern surface 3 of the printed circuit board 1 is coated with the solder resist film 8, the solder does not adhere to parts other than the through holes during solder dipping, and the conductor pattern It is possible to prevent a short circuit between the two.

Further, the solder resist film 8 is an insulator, and has a dense film surface and strong moisture resistance. This compensates for the disadvantage of the paper phenol material that it has a relatively high water absorption rate, prevents the pattern surface 3 from absorbing moisture, and increases the reliability of the insulation between the conductor patterns 4.

As shown in FIG. 4, before mounting the mounted components 5 on the component mounting surface 2, the component name symbol (indicated by C-1 in FIG. 4) and polarity symbol ( Ink markings 9 (indicated by 10 near the component hole 6 in Fig. 4), etc.
is printed to prevent incorrect mounting of the mounted components 5.

[Problem that the invention seeks to solve]

However, in the conventional single-sided printed wiring board mentioned above, the pattern surface becomes particularly hot during soldering, so
There is a problem in that the printed circuit board is warped or twisted, making it difficult to insert it into a guide such as a chassis or to fix it to a mounting plate.

Further, during use, the component mounting surface absorbs moisture and expands, causing the printed circuit board to warp and cause problems such as the mounted components hitting an adjacent printed board or other components.

Another problem is that the ink marking process for marking each mounted component on the component mounting surface is troublesome.

[Means for solving problems]

The above conventional problems can be solved by the present invention, in which a screen-printed solder resist film is formed on both the component mounting surface and the conductor pattern surface of a single-sided printed wiring board, except for the desired pattern area. Solved by single-sided printed wiring board.

[Effect]

According to the above means of the present invention, since the solder resist film is formed on the component mounting surface and the conductor pattern surface, mechanical rigidity is imparted almost symmetrically, thereby preventing warping, twisting, etc. during solder dipping. Decrease.

Furthermore, since the solder resist film is formed on the component mounting surface, the component mounting surface does not absorb moisture, so that the single-sided printed wiring board does not warp or twist during use.

Furthermore, the solder resist is screen printed on the component mounting surface using a mask pattern provided with component holes, component name symbols, etc., so that parts such as component name symbols, etc., are not printed in the same manner as the component holes. As a result, the color of the surface of the printed circuit board and the color of the solder resist film are different, so that component name symbols and the like can be read. Therefore, no special marking process is required.

〔Example〕

The gist of the present invention will be specifically explained below with reference to illustrated examples. Note that the same reference numerals indicate the same objects throughout the figures.

FIG. 1 is a sectional view of a single-sided printed wiring board according to an embodiment of the present invention, and FIG. 2 is a plan view of the component mounting surface side.

1 and 2, a conductor pattern 4 is formed on a pattern surface 3, which is one surface (lower surface in FIG. 1) of a printed circuit board 1. As shown in FIGS. In addition, on the component mounting surface 2, which is the other surface (the top surface in FIG. 1), the mounted components 5 are mounted by inserting the respective adhesives 5a of the mounted components 5 into the corresponding component holes 6. has been done.

The tip of this lead 5a faces the pattern surface 3 side,
The parts are dipped in solder and fixedly connected to the respective component lands 12 using solder 7.

Before mounting the mounting component 5, the pattern surface 3 is screen printed to form a solder resist film 8 using a desired mask pattern that does not print the component lands 12. Therefore, the entire surface of the pattern surface 3 including the surface of the conductor pattern 4, except for the component land 12, is coated with the solder resist film 8.

In addition, the component mounting surface 2 is provided with a component name symbol (indicated by C-1 in FIG. 2) around the component hole 6, a component name symbol (indicated by C-1 in FIG. 2) of the mounted component 5, and a polarity symbol (+ The solder resist film 10 is formed by screen printing using a desired mask pattern in which markings 11 such as (shown in ) are not printed.

A single-sided printed wiring board is constructed as described above, and the component mounting surface 2
Since the solder resist film 10 is formed on the pattern surface 3 and the solder resist film 8 is formed on the pattern surface 3, rigidity is imparted to the printed circuit board 1 almost symmetrically, thereby reducing warping, twisting, etc. during solder dipping.

Furthermore, since the solder resist film 10 is also formed on the component mounting surface 2, the component mounting surface 2 also does not absorb moisture like the pattern surface 3. Therefore, the printed circuit board 1 does not warp or twist during use. It never happens.

Therefore, the single-sided printed wiring board does not become an obstacle when inserted into a guide such as a chassis, or is easily fixed to a mounting plate. Further, the mounted component 5 does not collide with an adjacent printed board or other components.

Next, the marking 11 will be explained. printed circuit board l
The surface of the solder resist film 10 is, for example, brown, and the color of the solder resist film 10 is green. Therefore, since there is no solder resist film in the marking 11 portion such as a component name symbol, the marking 11 is displayed in the green color of the solder resist film 10 in the surface color of the printed circuit board 1.

Therefore, in the process of forming the solder resist film 1o, there is no need for a special printing marking process as in the past.
Markings 11 can be formed.

〔Effect of the invention〕

As explained above, the present invention reduces warpage, twisting, etc. of the printed circuit board by configuring a solder resist film of a desired pattern on the entire component mounting surface and conductor pattern surface of a single-sided printed wiring board. It is easy to insert and fix to a mounting plate, etc., and the mounted components do not bump into adjacent printed boards or other components, and it is easy to mark component names, etc. , has excellent practical effects.

[Brief explanation of drawings]

Fig. 1 is a sectional view of a single-sided printed wiring board according to an embodiment of the present invention, Fig. 2 is a plan view of the component mounting side, Fig. 3 is a sectional view of a conventional single-sided printed wiring board, and Fig. 4 is a sectional view of a conventional single-sided printed wiring board. FIG. 3 is a plan view of the mounting surface side. In the figure, l is a printed circuit board, 2 is a component mounting surface, 3 is a pattern surface, 4 is a conductor pattern, 5 is a mounted component, 5a is a lead, 6 is a component hole, 7 is solder, 8.10 is a solder resist film, Reference numeral 9 indicates ink marking, 11 indicates marking, and 12 indicates component land.

Claims (2)

[Claims] (1) Single-sided printed wiring characterized in that a screen-printed solder resist film is formed on both the component mounting side and the conductor pattern side of a single-sided printed wiring board, except for the desired pattern area. Board. (2) The single-sided printed wiring board according to claim 1, wherein markings for mounted components are included in desired pattern portions of the component mounting surface.