JPH021914Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a shielding device for electrically shielding electrical components disposed on, for example, a printed circuit board.

FIG. 1 shows this type of device, in which 1 is a printed circuit board, 2, 3, and 4 are resistors, high-frequency transformers, and integrated circuits arranged on this printed circuit board 1, and the upper surface of this integrated circuit 4 is shown in FIG. is provided with a metal shield lid 5 that serves both the lid function of the package and the shield function. Further, this shield plate 5 is connected to the ground terminal 6 of the integrated circuit 4 via a conductive wire.
2 shows a cross section taken along the line A-A' in FIG.
c penetrates the printed circuit board 1 and is connected to the conductive pattern 7 by a solder 8. Furthermore, a solder resist 9 is coated on the back side of the printed circuit board 1 in order to prevent the printed circuit board 1 from moisture and to provide voltage resistance between the conductive patterns 7 and the like.

In such a configuration, when power is applied and the resistor 2 disposed on the printed circuit board 1 is operated,
Internal noise generated by the transformer 3 etc. and external noise coming from outside enter the integrated circuit 4,
This caused malfunctions.

In order to reduce the influence of these noises, the integrated circuit 4
The shield lid 5 was connected to the ground terminal 6a via a conductive wire. However, this shield lid 5
As shown in the figure, the shielding range is small and the shielding range is also limited due to its structure, so a sufficient shielding effect could not be obtained. Furthermore, in this case, it is not possible to prevent the influence of noise propagated and radiated by the conductor pattern 7 on the back side of the printed circuit board 1 or the terminals 6 of the integrated circuit 4.

Furthermore, as a conventional shielding device, there is a method of reducing the influence of external noise by, for example, placing the entire electric circuit shown in FIG. 1 in a conductor case and grounding the conductor case. However, in this case, although the effect of suppressing external noise can be expected, internal noise, that is, resistance 2,
It is impossible to prevent the noise generated from the transformer 3 from entering the integrated circuit 4, and almost no effect on suppressing this internal noise can be expected.

This idea was made in order to eliminate the drawbacks of the conventional ones as mentioned above, and by providing an insulating layer on the surface of each electrical component and a conductive layer on this insulating layer, a special insulation mechanism is provided. The purpose of the present invention is to provide an electrical circuit shielding device that can be electrically shielded without any problems.

FIG. 3 is a cross-sectional view showing one embodiment of the present invention, and since the symbols 1 to 9 in FIG. 3 are the same as those in the conventional device shown in FIG. 2, their explanation will be omitted.

12 is the conventional printed circuit board 1 shown in FIG.
An insulating layer uniformly covers the outer surface of each electrical component such as the resistor 2, transformer 3, integrated circuit 4, etc., and 13 is a conductive layer uniformly covering the outer surface of this insulating layer 10, and this conductive layer is held at a ground potential. The connection is configured to

Note that the insulating layer 10 and the conductive layer 11 are deposited using a spray gun or the like.

In such a configuration, even if external noise arrives, each of the electrical components 1 to 4 is covered with the conductive layer 11 via the insulating layer 10, so the intrusion of external noise is prevented and sufficient noise and noise are prevented. It will be done.

On the other hand, internal noise generated inside each of the electrical components 1 to 4 is similarly prevented from radiating outward by the conductive layer 11, and is sufficiently suppressed.

Thereby, not only external noise but also internal noise is protected, and a stable and highly reliable electric circuit can be formed without the problem of the integrated circuit 4 malfunctioning as in the conventional case.

In addition, although the above embodiment describes the case of electrical components arranged on a printed circuit board, it may also be applied to other chassis wiring, three-dimensional circuits, etc., and electrical components are not limited to resistors, transformers, integrated circuits, etc.
Similar effects can be obtained even when applied to other electrical components.

As described above, according to this invention, since a conductive layer is uniformly deposited on the outer surface of each electrical component through an insulating layer, not only external noise but also each electrical component itself generates and radiates radiation. It has the advantage that it can provide sufficient immunity against internal noise and can be constructed at low cost.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a conventional shielding device, FIG. 2 is a sectional view taken along line A-A' in FIG. 1, and FIG. 3 is a sectional view showing an embodiment of the present invention. In the figure, 1 is a printed circuit board, 2 is a resistor, 3 is a transformer, 4 is an integrated circuit, 10 is an insulating layer, and 11 is a conductive layer. In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Scope of utility model registration request] An integrated circuit package arranged on a printed circuit board, a terminal led out from this package, and a conductive pattern provided on the back side of the printed circuit board to which the terminal is fixed by penetrating the printed circuit board. An electrical circuit comprising an insulating layer uniformly deposited on the outer surface of the insulating layer and a conductive layer uniformly deposited on the outer surface of the insulating layer, the conductive layer being maintained at a ground potential. Yahei device.