JPH01192191A - Printed wiring board - Google Patents

Abstract

PURPOSE:To obtain a structure which is simple in structure and able to shield an electronic circuit section that includes a shielding body by a method wherein a printed wiring board connects electronic components mounted on it with each other and a shielding pattern is provided to be interlinked with a wiring pattern which composes an electronic circuit. CONSTITUTION:A through-hole 8, which electrically connects a front wiring pattern 5 with a rear wiring pattern 5, is provided half way between a front shielding pattern 2 and a rear shielding pattern 3 shifted from each other. Electronic components 6 disposed at meshes respectively are successively connected with each other through the intermediary of the through-hole 8 and the wiring pattern 5 so as to compose a required electronic circuit. Concerning the printed wiring board, a current flowing through the wiring pattern 5 and the through- hole 8 is made to flow through a closed circuit composed of both the shielding patterns 2 and 3 and a shielding through-hole 4. Therefore, the radiation generated from the current which flows through the wiring pattern 5 and the through- hole 8 is attenuated as being absorbed by the above closed circuit, and thus a shielding effect can be attained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a shield structure for shielding radiation from electronic circuits on a printed wiring board.

[Conventional technology]

FIG. 4 shows a conventional shielding structure of an electronic circuit as disclosed in, for example, Japanese Utility Model Application Publication No. 192499/1983. In FIG. 1, (L) is Il! A substrate made of la material, (5
) is a wiring pattern formed on the substrate (1), and (6) is an IC.

These are electronic components such as capacitors and resistors, and the electronic circuit is composed of a substrate (1), a wiring pattern (5), and an electronic component (6). α・ is a frame made of metal, aD is an upper cover made of metal, and (2) is a lower cover made of metal. The frame Q11, the upper cover crane, and the lower cover (2) constitute a shield body, and this shield body The radiation is shielded by covering the outer periphery of the electronic circuit that is the radiation source.

[Problem to be solved by the invention]

In the conventional shielding structure as described above, even if the radiation from the electronic circuit of the printed wiring board is allowed below the standard, there is no simple shielding structure, so it is necessary to cover the outer periphery of the printed wiring board with metal plates, etc. It had a shield structure. Therefore, there were problems in that the external dimensions and thickness of the electronic circuit portion including the shield body became large, and the structure became complicated because the shield body was composed of separate parts.

This invention was made to solve the above problems,
The purpose is to obtain a structure that can shield an electronic circuit portion including a shield body with a simple structure.

[Means to solve the problem]

The printed wiring board of the present invention is provided with a shield pattern that connects electronic components mounted on the printed wiring board and interlinks with a wiring pattern that constitutes an electronic circuit.

[For production]

In this invention, a shield pattern provided on a printed wiring board attenuates radiation emitted from an electronic circuit by electromagnetic induction.

〔Example〕

FIG. 1 is a plan view showing an embodiment of the present invention, and FIG. 2 is a sectional view taken along line n-n in FIG.
1) is a substrate made of an insulating material, and (2) is a mesh-like surface shield pattern formed by etching the metal foil pasted on the surface of the substrate (1), leaving the necessary parts.

(3) is a mesh-like back shield pattern formed on the back side of the substrate (11) by the same method as in the above (2) and shifted horizontally and vertically from the front shield (2) in the plane projection direction.

(4 is a shield through hole, which connects both shield patterns +21. (21, 131) is provided at several places where they overlap in the planar projection of 31. (5) is a shield through hole that connects both shield patterns +21. pattern(
2).

(3) is a wiring pattern formed at the same time and using the same method, and is formed in a predetermined circuit wiring pattern on both sides of the substrate (IL).
(7) is a through hole into which the legs (terminals) of electronic component (6) are inserted, and the legs are connected to wiring pattern (5) with solder, etc., and fixed to the board (1), and (8) is the wiring on the surface. This is a through hole that connects the pattern (5) and the wiring pattern (5) on the back side, and is a front shield pattern +2
1 and the back shield pattern (3). This through hole (8) and the wiring pattern (
A predetermined electronic circuit is constructed by sequentially connecting to electronic components (6) in other meshes via the wires (5).

In the printed wiring board configured as described above, the current passing through the wiring pattern (5) and the through hole (8) is both shield patterns +21. +31 and the shield through hole (4). Therefore, the wiring pattern (5) and the through hole (
A shielding effect can be obtained by absorbing and attenuating radiation emitted from the current flowing through Bl by this closed circuit.

FIG. 3 is a cross-sectional view of a multilayer printed wiring board showing an embodiment of the present invention, and in the figure (1) to
(8) is the same as explained in the above embodiment,
(9) is a glabellar wiring pattern provided between the board +11, and is used in the case of a complicated circuit configuration.

Also in this embodiment, the shield pattern (21i3) and the shield through hole (4) can obtain the same shielding effect as in the above embodiment.

In addition, in the above embodiment, the shield pattern 12),
(According to experiments, the relationship between the shielding effect and the mesh size of 31 and the radiation frequency is as follows: L +, , = 40 Tsuru.

The attenuation was 5 dB in the case of Lx''30 days 1 frequency - 3QOMHz.

〔Effect of the invention〕

By providing this, it is possible to shield the electronic circuit section including the shield body with a simple structure.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing one embodiment of the present invention, FIG. 2 is a sectional view taken along line nn in FIG. 1, FIG. 3 is a sectional view showing another embodiment of the invention, and FIG. The figure is a sectional view showing a conventional shield structure. In the figure, +11 is a board, (2) is a front shield pattern, (3) is a back shield, a shield pattern, (5) is a wiring pattern, and (6) is an electronic component. Note that the same reference numerals in each figure indicate the same or corresponding parts. Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] A printed wiring board characterized by comprising a wiring pattern that connects electronic components mounted on the printed wiring board to form an electronic circuit, and a shield pattern that interlinks with the wiring pattern.