JPH05145269A - Electronic apparatus - Google Patents

Abstract

PURPOSE:To obtain a high shielding effect and a high heat-dissipation effect of a shielding member, together with reducing the formal size of a shielding system to a minimum. CONSTITUTION:An electric circuit board 2 is covered with a shielding member 1 comprising a mesh-like conductor which is so covered by an insulator as to leave the holes of its mesh intact, and the conductor of the shielding member 1 is connected with the earth part of the circuit board 2. Even though the shielding member 1 is contacted with the elements provided on the circuit board 2, there is no problem for it is covered with the insulator. Therefore, the shielding member 1 is used compactly in a lump, and the electronic apparatus using it can be made compact. Also, the high heat-dissipation effect of the shielding member 1 can be obtained by making its form mesh-like.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic device having an electric circuit board covered with a shield member that shields radio waves.

[0002]

2. Description of the Related Art Conventionally, in electronic equipment such as a document creation device,
Radio waves such as malfunction of own electronic device and other electronic devices occur due to miscellaneous radio waves generated from the electronic device itself, radio waves from the outside, and the like. Therefore, a structure is adopted in which the electric circuit board is surrounded by a shield member, and the shield member is electrically connected to the ground portion of the electric circuit board to block internal and external radio waves.

For example, the electric circuit board (not shown) in the housing 5 of the document creating apparatus 10 shown in FIG. 3 is covered with the shield member shown in FIGS. 4 and 5. As shown in FIGS. 4 and 5, the shield member includes a box-shaped upper shield plate 11 and a lower shield plate 12 which are formed by sheet metal forming a shield material, and the shield member sandwiches the electric circuit board 2. They are placed one above the other. The upper shield plate 11 and the lower shield plate 12 are attached to their respective mounting flange portions 13 and 14
Is brought into contact with and fixed to a ground pattern (not shown) of the electric circuit board 2. Upper shield plate 11 and lower shield plate 1
The electric circuit board 2 encapsulated by 2 is housed in a housing 5a composed of an upper case 3a and a lower case 4a as shown in FIG.

As a means for shielding the electric circuit board 2, in addition to the above-mentioned shield member, a casing 5a (FIG. 3) in which the electric circuit board 2 is housed may be conductively painted or plated. Has been adopted.

[0005]

The shield member shown in FIGS. 4 and 5 has the following problems. That is, various elements and element legs are arranged so as to project on the electric circuit board 2. Therefore, these and the upper shield plate 1
It is necessary to take sufficient clearance to avoid contact with the lower shield plate 1 and the lower shield plate 12. Therefore, the volumes of the upper shield plate 11 and the lower shield plate 12 become large, which causes a problem that it becomes difficult to store them in the compact housing 5a.

Further, since the electric circuit board 2 becomes extremely high in heat, it is necessary to release generated heat. Therefore, it is necessary to form a heat dissipation hole in the upper shield plate 11 and the lower shield plate 12. However, since the shield effect is reduced in proportion to the size of the diameter of the heat dissipation hole, it is possible to provide a heat dissipation hole of a sufficient size. Absent.

On the other hand, in the case of a means for conducting the inside of the casing 5a with conductive treatment such as conductive coating or conductive plating, masking is required between the outer surface of the casing 5a and the inside during the conducting treatment, and the work process However, there is a problem that it becomes complicated and the manufacturing cost becomes high. Further, since the housing 5a is usually composed of two or more parts, means for electrically connecting the parts is required, which causes a problem of high cost.

An object of the present invention is to solve the above problems, and an object thereof is to provide a structure of an electronic device which has a high shielding property and a high heat dissipation property and can be compactly assembled to save space.

[0009]

According to the present invention to solve the above problems, there is provided an electronic device having an electric circuit board covered with a shield member for shielding a radio wave, wherein the shield member has a mesh shape. The conductor was covered with an insulator so as to leave the holes of the mesh, and the conductor was electrically connected to the ground portion of the substrate.

[0010]

Since the shield member is made of a mesh-shaped conductor covered with an insulator, there is no particular problem even if the shield member comes into contact with the electronic circuit board to be encapsulated, and the shield member can be compactly assembled.
Further, since it is formed in a mesh shape, it has good air fluidity and can dissipate heat from the electric circuit board.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

First Embodiment FIG. 1 illustrates a shield structure for an electronic device according to a first embodiment of the present invention. In FIG. 1, reference numeral 1 is a shield member, reference numeral 2 is an electric circuit board, reference numeral 3 is an upper case, and reference numeral 4 is a lower case. The case 5 (FIG. 3) is formed by the upper case 3 and the lower case 4.

The shield member 1 is in the form of a bag, and is formed by laminating a copper mesh with an insulator while leaving mesh holes. The bag-shaped shield member 1 completely encloses the electric circuit board 2. Although a large number of elements and element legs are arranged on the electric circuit board 2, since the shield member 1 is an insulator, it can come into contact therewith and is formed in a compact shape.

On the other hand, although not shown in the drawing, a ground pattern is formed on the fixing portion 6 fixed to the lower case 4 of the electric circuit board 2, and the attaching portion 7 of the shield member 1 which overlaps with the earth pattern is made of a laminated insulator. Are being removed. That is, the electric circuit board 2 is covered with the shield member 1, the screws 8 are inserted into the mounting portion 7 and the fixed portion 6, and the lower case 4 is tightened, so that the shield member 1 is pressed against the earth pattern of the electric circuit board 2. And are electrically connected.

With the above structure, the electric circuit board 2 is surrounded by the shield member 1 and the radio wave can be shielded. Further, since the shield member 1 is formed in a mesh shape, it has a high air fluidity, so that the heat in the shield member 1 can be radiated to the outside and the heat accumulation can be minimized. Further, the shield member 1 is made of a single piece of copper mesh formed into a bag shape, and is different from the contact resistance of the contact portions between the seal materials as in the case of stacking a plurality of (two) shield materials as in the prior art. Attenuation of the shield effect can be minimized, and a high shield effect can be obtained.

Second Embodiment In the first embodiment, the shield member 1 and the electric circuit board 2 are electrically connected to each other by pressing the insulation-removed mounting portion 7 of the shield member 1 against the ground pattern of the electric circuit board 2. However, in the second embodiment, the two are electrically connected by the conductor member 9 shown in FIG.

The conductor member 9 is made of a clip and is connected to the copper mesh of the shield member 1 by a lead wire, and one to several conductor members 9 are provided. Clip-shaped conductor member 9
The shield member and the electric circuit board 2 are electrically connected to each other by sandwiching the resist pattern of the electric circuit board 2 into the ground pattern from which the resist has been removed.

According to the second embodiment, the effect of facilitating the connection between the shield member 1 and the electric circuit board 2 as compared with the electric connection by the screw 8 of the first embodiment is enhanced.

In the first embodiment, the bag-shaped shield member 1
However, when only the upper side or the lower side of the electric circuit board 2 needs to be shielded, a sheet-shaped shield member is covered or laid on the upper side or the lower side of the electric circuit board 2,
It may be electrically connected to the ground portion of the circuit board 2. In this case, as compared with the case where the bag-shaped shield member 1 covers the electric circuit board 2, it is possible to enhance the heat dissipation effect and configure a shield system having a minimum size. Further, in the above description, the shield member 1 is made of copper mesh, but other mesh-shaped conductors may of course be used.

[0020]

As described above, according to the present invention, as the shield member, a mesh-shaped conductor covered with an insulator in the form of a mesh hole is used, and the shield member is formed into a bag or By arranging the electric circuit board in the form of a sheet so as to cover the electric circuit board, a large shield effect can be achieved by a shield member having a minimum size and a heat dissipation effect can be improved. Further, since the shield member is formed of a bag-shaped or sheet-shaped member, it can be made as compact as possible and the housing can be made compact.
Further, unlike a case where a plurality of members are stacked, a high shield effect can be obtained without the attenuation of the shield effect due to the contact resistance of the overlapping portion.

[Brief description of drawings]

FIG. 1 is a perspective view of an embodiment of the present invention.

FIG. 2 is a perspective view of a main part showing a connection structure between a shield member and an electric circuit board according to another embodiment.

FIG. 3 is a perspective view showing an external appearance of a document creation device to which the present invention is applied.

FIG. 4 is a cross-sectional view showing a conventional shield structure.

FIG. 5 is a perspective view showing a conventional shield structure.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 shield member 2 electric circuit board 3 upper case 4 lower case 5 housing 6 fixing part 7 mounting part 8 screw 9 conductor member 10 document preparation device

Claims (1)

[Claims] 1. An electronic device having an electric circuit board covered with a shield member for radio wave shielding, wherein the shield member is formed by covering a mesh-shaped conductor with an insulator so as to leave holes in the mesh. The electronic device is characterized in that the conductor is electrically connected to a ground portion of the substrate.