JPH088573A - Structure for shield case - Google Patents

Abstract

PURPOSE:To prevent the leakage of signals to upper and lower substrate, adjacent circuits and the outside and the interference of signals in a multilayered substrate having circuits which generate high frequencies including an oscillation circuit. CONSTITUTION:A multilayered substrate 1 having a along rectangular through hole 4 and metallized side faces formed by plating is put between an upper metallic cover 2 and a low metallic cover 3. Therefore, the leakage of signals and interference between the upper and lower substrates and between adjacent circuits of the substrate 1 can be prevented and the leakage of signals to the outside of the lower cover 3 from the upper cover 2 can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shield case structure, and more particularly to a shield case structure for a high frequency circuit for microwave radio communication devices.

[0002]

2. Description of the Related Art In a conventional shield case structure, a multilayer circuit board 9 is provided inside a case 8 as shown in FIG. 2, various electric parts 6 are provided, and an oscillating circuit 7 and other high frequency circuits are provided. In the circuit that generates the signal, a metallic shield plate 10 is erected so as to prevent the signal from leaking to other circuits to shield the other circuits. Such a shield case structure is described in, for example, JP-A-1119096.

[0003]

In this conventional shield case structure, the frequency of a circuit that generates a high frequency such as an oscillating circuit becomes high, and in the microwave band, the space between the upper substrate and the lower substrate of the multilayer substrate is increased. However, there is a problem that a large amount of signal leaks between adjacent circuits and from the inside of the shield case to the outside, which causes deterioration of electrical characteristics. As described above, an object of the shield case structure of the present invention is to provide a shield case structure having a sufficient shield effect even in a microwave band where the conventional leak shield structure cannot sufficiently prevent signal leakage interference.

[0004]

A shield case structure of the present invention is a shield case structure for shielding a plurality of high-frequency circuits mounted on a printed circuit board, wherein a side surface metalide for plating a peripheral side surface of the printed circuit board and the side surface. A plurality of through-holes are provided around the plurality of high-frequency circuits except for metallides, and a metallic upper and lower cover that sandwiches the printed circuit board from above and below so as to contact the side surface metallization and the plurality of through-holes. It is equipped with.

[0005]

The present invention will be described below with reference to the drawings. FIG. 1A shows a shield case structure according to an embodiment of the present invention. This shield case structure is composed of a multi-layer substrate 1 having a rectangular through hole 4 and a side surface metallization 5 for plating the side surfaces, a metallic upper cover 2 and a lower cover 3 for shielding the upper and lower portions of the multi-layer substrate 1. Has been done.

FIG. 1B is a sectional view of the shield case structure taken along the line AA 'in FIG. 1A. The upper substrate and the lower substrate of the multi-layer substrate 1 have various electric components 6 and a circuit for generating a high frequency including an oscillation circuit 7.

The long hole through hole 4 is brought into the same electric potential as the ground potential of the upper cover 2 and the lower cover 3 by mechanically contacting the upper cover 2 and the lower cover 3, thereby electrically providing a shielding effect. . Also, the long hole through hole 4 is
Since a large number of shields are provided around each circuit that requires a shield shielded by the upper cover 2 and the lower cover 3, the shield between the circuits is sufficiently effective even for a high frequency signal in the microphone band.

On the other hand, the side surface metallization 5 of the present multilayer substrate 1
Mechanically comes into contact with the outer side surfaces of the upper cover 2 and the lower cover 3 to have the same potential as the ground potential of the upper cover 2 and the lower cover 3, thereby electrically providing a shielding effect.

Further, since the side surface metallization 5 shields the entire outer peripheral surfaces of the upper cover 2 and the lower cover 3, the high frequency signal in the shield case is unnecessarily transmitted to the outside or an unnecessary wave is generated from the outside. It prevents you from typing.

As described above, the shield structure of the present invention is the multilayer substrate 1
However, it is needless to say that the double-sided substrate having the long hole through hole 4 and the side surface metallization 5 of the present invention is not limited to the multilayer substrate and has the same effect.

[0011]

As described above, according to the present invention, by providing elongated through-holes and side surface metallization in a multilayer substrate and sandwiching a metallic shield cover from above and below the multilayer substrate, an adjacent circuit and an upper circuit can be formed. It can be applied to the shield of high frequency circuits in the microwave band, for example, by enhancing the shielding property of the lower circuit and the outside. Further, since the structure is simple, it also has the effect of being able to downsize the communication device.

[Brief description of drawings]

FIG. 1A is a structural diagram of a shield case according to an embodiment of the present invention. (B) It is a shield cross-sectional view of one embodiment of the present invention.

FIG. 2 is a structure diagram of a conventional shield case.

[Explanation of symbols]

 1 Multilayer Substrate 2 Upper Cover 3 Lower Cover 4 Long Hole Through Hole 5 Side Metallization 6 Electrical Components 7 Oscillation Circuit 8 Shield Case 9 Multilayer Substrate 10 Shield Plate

Claims (3)

[Claims] 1. A shield case structure for shielding a plurality of high-frequency circuits mounted on a printed circuit board, wherein a side surface metallization for plating a peripheral side surface of the printed circuit board and the side surface metallization are provided around the plurality of high-frequency circuits. A shield case structure comprising a plurality of through holes, and a metallic upper cover and a lower cover that sandwich the printed circuit board from above and below so as to contact the side surface metallization and the plurality of through holes. . 2. The shield case structure according to claim 1, wherein the printed circuit board is a multilayer board having two or more layers. 3. The shield case structure according to claim 1, wherein the through hole has an elongated hole shape.