JPH0211037B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field: This invention relates to a method and apparatus for shielding electrical equipment from electricity or magnetism.

"Prior Art" Conventionally, as shown in FIG. 3, this type of method or apparatus includes a printed circuit board in which a conductive thin film 3 is formed on the inner wall surface of a case 1 made of synthetic resin, and an electronic circuit is formed inside the case. There is one in which the lead wire 6 that electrically connects the ground conductor of the substrate and the conductive thin film 3 is made of an elastic material, and the lead wire is brought into elastic contact with the conductive thin film. This method can reduce conductivity due to surface oxidation of the elastic material, or when used as a product, may cause non-contact problems due to resonance in places with vibrations, or the contact point between the conductive thin film and the lead wire. There is a problem that this may cause damage, which may cause non-conductivity.

In order to solve this problem, there is a method of bonding one end of the lead wire 6 to a conductive thin film using a conductive adhesive 5, as shown in FIG. The wire 6 cannot be moved and the method of fixing it is difficult, and as the shape of the case 1 becomes more complex, the workability becomes worse.

Alternatively, as shown in Fig. 5, there is a method in which a conductive adhesive 5 is applied to a conductive thin film 3, the adhesive is dried, and a lead wire is directly soldered 7 to this. This has the disadvantage that the thin film 3 itself is often destroyed, and the underlying resin material, that is, the case 1, is also melted and deformed.

Furthermore, as shown in FIG. 6, there is a method in which the lead wire 6 is mechanically fixed to the case 1 etc., for example, by a metal ring 11 with a screw 12, and then a metal is vapor-deposited or a conductive paint is applied thereon. However, since the interface area of the lead wire 6 or the attached terminal of the lead wire is small, that is, the membrane 3 is too thin, there is a drawback that the joint portion is easily broken due to expansion of the underlying resin.

Alternatively, as shown in FIG. 7, there is a method of covering the outer periphery of the case with a metal box 13, but this method has the disadvantage of complicating the manufacturing method and increasing the cost.

"Purpose" This invention takes into consideration the drawbacks of the conventional technology, and
The present invention aims to provide a stable shielding method and device.

"Embodiment" An embodiment of the present invention will be described below with reference to the drawings.

That is, in FIG. 1, an insulating case 1 is made of synthetic resin, and a printed circuit 2 forming an electronic circuit is accommodated within this case. Further, a conductive thin film 3 is formed on the inner wall surface of the case 1 by means such as vapor deposition. Furthermore, a tape-shaped metal foil 4 is pasted on this conductive thin film. The back surface of this metal foil is coated with an adhesive in advance, and the material of the metal foil is, for example, copper foil. Furthermore, a conductive adhesive 5 is applied at the peripheral edge of the metal foil 4 over the metal foil and the conductive thin film 3, thereby electrically connecting them to each other. Then, with the adhesive 5 hardened, one end of the lead wire 6 is soldered 7 to the metal foil 4, and the other end of the lead wire is electrically connected to the ground conductor 9 of the printed circuit board 2 by soldering 8, etc. connected to.

This shields the electronic circuitry within the case 1, including the printed circuit board 2, from electricity or magnetism.

In the case shown in FIG. 2, the middle part of the metal foil 4 is placed a little apart from the conductive thin film 3, and both ends are glued to the conductive thin film 3, so that when the case 1 is expanded due to heat, It also absorbs that growth.

"Effects" According to the present invention, the conductive thin film 3 and the metal foil 4 are bonded together with the conductive adhesive 5, so that sufficient conduction can be obtained, and the metal foil 4 and the lead wire 6 are connected by soldering 7. Since the connection is made with
Furthermore, it is sufficient to use a small amount of the metal foil 4, and therefore it is inexpensive.

[Brief explanation of drawings]

FIG. 1 is a side sectional view showing an embodiment of the shielding method and device for electrical equipment according to the present invention;
FIG. 2 is a side sectional view showing another embodiment of the invention;
FIGS. 3-7 are side cross-sectional views illustrating a conventional method and apparatus. DESCRIPTION OF SYMBOLS 1... Case, 2... Printed circuit board, 3... Conductive thin film, 4... Metal foil, 5... Conductive adhesive, 6...
Lead wire, 7...Soldering, 8...Soldering, 9...Ground conductor.

Claims (1)

[Claims] 1. Forming a conductive thin film on the wall of an insulating case, and pasting metal foil on the conductive thin film,
and applying a conductive adhesive for electrically connecting the metal foil and the conductive thin film to each other on the peripheral edge of the metal foil so as to span the metal foil and the conductive thin film, A method for shielding electrical equipment, comprising: soldering one end of a lead wire to the metal foil, and further connecting the other end of the lead wire to a ground conductor of a printed circuit board forming an electronic circuit. 2. An insulating case, a conductive thin film formed on the wall of the case, a metal foil pasted on the conductive thin film, and a metal foil that straddles the metal foil and the conductive thin film at the peripheral edge of the metal foil. It consists of a conductive adhesive that is applied to electrically connect these two to each other, and a lead wire that has one end connected to the metal foil and the other end connected to the ground conductor of the printed circuit board forming the electronic circuit. shielding equipment for electrical equipment.