JPH0132390Y2 - - Google Patents

Description

[Detailed explanation of the invention] Industrial application field This invention is a plastic material for electromagnetic shielding.
It concerns housing.

BACKGROUND TECHNOLOGY In general, when installing electronic equipment, measures are taken to prevent the electronic equipment from emitting interference radio waves and having a negative impact on other electronic equipment in the vicinity, or to prevent the electronic equipment from generating interference radio waves from outside. Equipment must be installed to block electromagnetic waves to prevent malfunctions. In recent years, automation of molding, freedom of design,
Plastic housings are often used as housings for electronic devices due to their light weight and cost efficiency, but they are transparent to interfering electromagnetic waves. For this reason, conventionally, a conductive layer was provided inside the plastic housing to block electromagnetic waves. However, such conventional plastic housings have the following problems.

That is, conventional plastic housings are made of laminates with an insulating layer made of thermoplastic synthetic resin and a conductive layer made of thermoplastic synthetic resin mixed with a conductive filler. Cuts with a V-shaped cross section were provided in the inner conductive layer at predetermined locations in the laminate to bend the corners at right angles or other predetermined angles. When the laminate is bent through this cut, the end surfaces of the conductive layer portions separated from each other on both sides of the cut are unlikely to come into close contact with each other.
For this reason, the conductive layer is not partially connected at the corners of the housing, and electromagnetic waves leak from the corners of the housing, making it impossible to obtain a stable shielding effect.

To solve this problem, conventional methods have involved cutting a strip of conductive reinforcing material inside the housing corner and pasting it so that it spans the conductive layer on both sides, or applying conductive paint. However, in the former case, there is a risk that the reinforcing material may peel off due to heat or vibration during long-term use of the housing;
In the latter case, the disadvantage is that the conductive coating may peel off and fall, or cracks may occur in the conductive coating at the cut areas, creating discontinuous areas in the conductive layer, which also reduces the electromagnetic shielding effect. It was hot.

Purpose of the invention The purpose of this invention is to eliminate the above-mentioned drawbacks, to be able to reliably connect and conduct the conductive layers at the corners of the housing, to obtain a complete electromagnetic shielding effect, and to have a simple structure. It is an object of the present invention to provide a plastic housing for electromagnetic shielding that is simple, can be manufactured easily and inexpensively, and can withstand long-term use.

Structure of the Device In order to achieve the above object, the device includes a laminate comprising an insulating layer made of a thermoplastic synthetic resin and a conductive layer made of a thermoplastic synthetic resin mixed with a conductive filler. This is a plastic housing for electromagnetic shielding, in which the laminated plate that is to form the corner of the housing is provided with cuts to separate the conductive layer at required locations, a piece of wire mesh is placed in the cut, and the laminated plate is attached to the wire mesh. Plastic for electromagnetic shielding, in which the edges of the conductive layer on both sides of the notch are softened by heating when bent with the single cut inward, forming corners where pieces of wire mesh are embedded in the conductive layer.・The gist is housing.

Embodiments and Operations Next, embodiments of this invention will be described based on the drawings.

In the drawing, a plastic housing 1 for electromagnetic shielding according to this invention is made of a conductive synthetic resin laminate 2 and has a substantially box shape with an opening downward, and a steel base 3 is mounted on the bottom surface of the plastic housing 1. It is fastened.

The laminate 2 has an insulating layer 4 made of thermoplastic synthetic resin.
and a conductive layer 5 made of a thermoplastic synthetic resin mixed with a conductive filler. The insulating layer 4 has a thickness of, for example, 1 to 5 mm, and is made of thermoplastic synthetic resin such as vinyl chloride resin, ABS resin, polyethylene resin, and polypropylene resin. The conductive layer 5 has a thickness of, for example, 1 to 3 mm, and is made of the same thermoplastic synthetic resin as described above mixed with a conductive filler. As the conductive filler, carbon black, carbon fiber, metal-plated glass fiber, metal ribbon or flake, metal fiber, etc. are used. The insulating layer 4 and the conductive layer 5 are integrated by heating and pressing,
An adhesive layer may be appropriately interposed between the layers 4 and 5.

As shown in FIG. 4, cuts 6 having a V-shaped cross section for separating the conductive layer 5 are provided at required locations on the laminated plate 2 where the corner portion 1a of the housing 1 is to be formed.
A wire mesh piece 7 is housed within this notch 6 over its entire length. The cut 6 separates the conductive layer 5 and has a depth that slightly penetrates into the insulating layer 4, so that the insulating layer 4 is connected.

The wire mesh piece 7 is made of metal such as aluminum, iron, brass, and copper. The width of the wire mesh piece 7 accommodated in the cut 6 having a V-shaped cross section may be equal to or slightly smaller than the width of the inclined inner surface of the cut 6, and the mesh of the wire mesh piece 7 should be at least as thick as the thickness of the conductive layer 5. It needs to be smaller. The length of the wire mesh piece 7 is approximately the same as the length of the cut 6.

Then, in a state where the laminated plate 2 is bent with the notches 6 into which the wire mesh pieces 7 are inserted, the ends of the conductive layer portions 5a, 5a on the side of the notches 6 are softened by heating, and the conductive layer portions are formed into the mesh of the wire mesh pieces 7. 5a,
A corner portion 1a in which the wire mesh piece 7 is embedded in the conductive layer 5 is formed by partially entering the wire mesh piece 5a. Electrical communication is established through the The illustrated electromagnetic shielding housing 1 is used as a housing for an electronic device such as a fish finder, and a screen 8 is provided on its front wall.

Note that the corners of the plastic housing 1 are not all formed by bending the laminated plate 2, but for example, the corners 1a of the top wall and the four walls facing it on the front, rear, left and right sides are formed. is formed by bending the laminated plate 2, and the laminated plate 2 is completely separated at the other corners 1b. These corners 1
In b, the connecting ends of adjacent walls are connected using, for example, a conductive reinforcing plate.

In addition, the inner surfaces of the left and right side walls 11 and 12 of the plastic housing 1 have screw holes 1 opened downward.
Brackets 14, 14 having screw holes 1, 13 are respectively attached, and the upper end male threaded portions of double threaded bolts 15, 15 passing through the base 3 are inserted into these screw holes 1.
3 and 13, and nuts 16 and 16 are screwed onto the lower end male threaded portion of the base 3.
is attached to the lower surface of the housing 1. A rising wall 17 is provided at the periphery of the base 3, and a notch 18 having a cross section of > shape is provided horizontally on the inner surface of the lower edge portion of the peripheral side wall of the housing 1.
A conductive sealing material 19 is fitted into this notch 18, and the sealing material 19 is sandwiched between the peripheral side wall of the housing 1 and the rising wall 17 of the base 3. Furthermore, legs 20 made of synthetic rubber, synthetic resin, or the like are attached to the four corners of the lower surface of the base 3.

In the above embodiment, the housing 1 has a box shape, but it may have other shapes such as a chevron shape. Furthermore, the housing 1 is made of a laminated board 2 except for the base 3 and the screen 8.
In this invention, among the walls constituting the housing 1,
It is applicable as long as at least two side walls are formed by bending the laminated plate 2. Although the bending angle of the corner portion 1a of the housing 1 is 90 degrees in the illustration, it is not limited to this and may be any other suitable angle.

Effects of the invention As described above, this invention includes a laminate 2 composed of an insulating layer 4 made of a thermoplastic synthetic resin and a conductive layer 5 made of a thermoplastic synthetic resin mixed with a conductive filler. In the plastic housing 1 for electromagnetic shielding, cuts 6 for separating the conductive layer 5 are provided at required locations on the laminated plate 2 that is to form the corner portion 1a of the housing 1, and a piece of wire mesh 7 is provided in the cuts 6. When the laminated plate 2 is folded with the notch 6 containing the wire mesh piece 7 inside, the ends of the conductive layer portions 5a, 5a on both sides of the notch 6 are softened by heating.
A corner portion 1a is formed in which a piece of wire mesh 7 is embedded in the conductive layer 5, and the conductive layer 5 can be reliably connected to the corner portion 1a of the housing 1 via the piece of wire mesh 7 to establish continuity. It is possible to obtain a complete electromagnetic shielding effect. Furthermore, since an inexpensive piece of wire mesh 7 is simply embedded in the conductive layer 5 at the corner 1a of the housing 1, the structure is very simple and can be manufactured easily and at low cost. Also, the conductive layer portions 5a, 5 on both sides of the cut 6
a is softened by heating, and a part of it enters the mesh of the wire mesh piece 7, and the wire mesh piece 7 becomes embedded in the conductive layer 5, so that the wire mesh piece 7 is softened by external or internal stress. The housing 1 has the advantage of being able to withstand long-term use without coming off or falling off from the corner 1a.

[Brief explanation of the drawing]

The drawings show an embodiment of this invention; FIG. 1 is a partially enlarged perspective view of a corner of the housing, FIG. 2 is a partially cutaway perspective view of the housing with a base, and FIG.
The figure is a sectional view taken along the line of FIG. 2, and FIG. 4 is a partially enlarged perspective view of the laminate before forming the corner portion of the housing. DESCRIPTION OF SYMBOLS 1... Plastic housing for electromagnetic shielding, 2... Laminate plate, 3... Base, 4... Insulating layer, 5... Conductive layer, 5a, 5a... Conductive layer portion,
6...notch, 7...piece of wire mesh.

Claims (1)

[Scope of utility model registration request] An insulating layer 4 made of thermoplastic synthetic resin, and a conductive layer 5 made of thermoplastic synthetic resin mixed with a conductive filler.
A plastic housing 1 for electromagnetic shielding is provided with a laminated plate 2 configured by the above, and cuts for separating the conductive layer 5 are provided at required locations of the laminated plate 2 where the corner portion 1a of the housing 1 is to be formed. 6 is provided, a piece of wire mesh 7 is housed in this cut 6, and when the laminated plate 2 is bent with the cut 6 containing the wire mesh piece 7 inside, the ends of the conductive layer portions 5a, 5a on both sides of the cut 6 are A plastic housing for electromagnetic shielding, which is softened by heating to form a corner 1a in which a wire mesh piece 7 is embedded in a conductive layer 5.