JPH04119700A - Shielding structure of electronic equipment - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a shielding structure for electronic equipment when the casings of electronic equipment whose surfaces are insulating layers are connected to each other. [Prior Art] Conventionally, electromagnetic shielding has been applied to the housings of electronic devices according to VCCI (Voluntary Control Council for Interference with Information Processing Equipment) regulations. For example, in a television receiver or the like, since radiated radio waves are generated from a CRT, it is necessary to have radio wave shielding properties. Electronic devices that use conductive plastic or decoratively coated metal as electromagnetic shielding materials have an insulating coating on their surfaces, so it is difficult to ensure electrical connection when they are bonded. is difficult. Conductive plastic is made by dispersing conductive filler inside the plastic, so the inside of the plastic maintains conductive properties due to the action of the filler, but the outermost surface has a skin layer that is an insulating layer during molding. is formed, making it difficult to obtain electrical connections at the end faces. In this case, the presence or absence of electrical connection at the joint portion influences the electromagnetic shielding effect. For example, in the device described in JP-A-1-41300, a conductive elastomer strip (a conductive rubber piece with fitting grooves and protrusions) is fitted onto the end face of a conductive plastic. By maintaining an electrical connection,
I was using electromagnetic shielding. In this case, in order to bond the conductive elastomer and conductive plastic, heat fusion or solvent bonding is used, and the skin layer, which is an insulating layer, is destroyed by heat or solvent, and the internal conductive layer (conductive filler) and conductive By fusing them with an elastomer (conductive rubber), they are electrically connected. [Problems to be Solved by the Invention] As mentioned above, in the conventional method, the conductive filler inside the conductive plastic and the conductive elastomer are electrically bonded by heat fusion or solvent bonding. The work was complicated6.Furthermore, the conductive elastomer to be bonded to the outside must be suitable for heat fusion or solvent bonding, which inevitably limits the material it can be made of. Furthermore, in order to achieve electrical connection at the end face of the painted case, it is necessary to perform masking painting or scraping off the surface coating after painting. This process has a problem that the workability is very poor and the quality of the electrical connection becomes highly variable. The purpose of the present invention is to solve these conventional problems, to create an electronic device that can ensure electrical connection at the end face of a conductive plastic or painted case, and that can easily shield the case from electromagnetic waves. The purpose is to provide a shield structure. [Means for Solving the Problems] In order to achieve the above object, the shield structure of an electronic device according to the present invention is (a) made of a conductive material, and has a protrusion on the inside and a conductive contact on the outside. By providing the attached joint piece and inserting the joint piece into the metal case or conductive plastic material on the end face of the housing, the protrusion will pierce the inside of the conductive plastic and connect electrically, and the conductive contacts will be connected to each other. The feature is that the casing is electrically connected to shield the casing from electromagnetic waves. (b) The joint piece has a curved metal surface that matches the outer shape of the conductive contact body,
A U-shaped member that sandwiches the conductive plastic or metal case on the end face of the casing from both sides of the metal surface, and a protrusion that is attached to the tip of the member and sticks into the conductive plastic or metal case on the end face of the casing. 6 Also, (c) the joining piece is attached to the conductive contact body and is attached to the conductive contact body, and when sandwiching the conductive plastic member or metal case on the end face of the casing from the outside. Another feature is that it includes a metal part provided with a plurality of slits to enable bending, and a protrusion provided inside the metal part. Furthermore, (d) the connecting piece has an S-shaped shape that is attached to the conductive contact body and inserts a conductive plastic member or metal case on the end surface of the casing into the U-shaped groove of one of the conductive contact bodies. It is also characterized in that it includes a metal member having a handle and a protrusion attached to the inside of the metal member. [Function] In the present invention, a protrusion made of metal, conductive plastic, or ceramic is inserted into the conductive plastic from its surface. This protrusion protrudes inside the metal, conductive plastic, or ceramic that is shaped to sandwich the end surface of the casing. A conductive gasket or a conductive elastomer is attached as a conductive contact to the opposite surface of the protrusion. For attachment, use conductive adhesive or conductive double-sided tape to ensure electrical connection. The joint piece between the inner protrusion and the outer conductive contact body can destroy the painted surface film of the painted case and electrically connect it to the internal metal part. [Example] Hereinafter, an example of the present invention will be described in detail with reference to the drawings. FIGS. 1(a) and 1(b) are cross-sectional views of a conductive plastic and a bonding piece, respectively, showing a first embodiment of the present invention. In FIG. 1, 1 is a conductive plastic, 2 is a conductor, 3 is a skin layer, 4 is a joining piece, 5 is a protrusion, 6 is a conductive adhesive, and 7 is a conductive contact. The conductive plastic 1 includes a conductor portion 2 containing a conductive filler such as SUS fiber, Cu fiber, and C powder, and a skin layer 3 that is an insulating layer with a thickness of 10 to 50 μm present on the surface.
formed from. This conductive plastic 1 forms a housing that covers an electronic device such as a television receiver. A joining piece 4 according to the invention was then provided for joining two conductive plastics 1. The joint piece 4 shown in FIG. 1(b) has a U-shaped cross section and has a protrusion 5 on the inside, and a conductive adhesive 6 and a conductive contact 7 on the outside. As for the material of the joint piece 4, metals with high conductivity and resistance to oxidation, such as stainless steel and beryllium copper, are used, but plastics, ceramics, etc. may also be used as long as they have conductivity. . The protrusion 5 of this embodiment is inserted into the conductive plastic l from the surface and electrically connected to the conductive filler inside the conductive plastic 1. Existing metals or conductive plastic or ceramic materials and the conductive plastic 1 are also bonded in the same way. A conductive elastomer or a conductive gasket, which is the conductive contact body 7, is attached to the surface of the joint piece 4 using a conductive adhesive 6 or a conductive double-sided tape. Therefore, the electrically conductive plastic 1 and the electrically conductive elastomer or electrically conductive gasket present on the end surface of the electrically conductive plastic have the same potential, and electrical connection of the joint portion is ensured via this elastomer or gasket. As a result, electrical connection can be made at the end face of the conductive plastic l. i! ! Even in the case of a protective case, the protrusions break through the paint film and electrically connect with the metal inside.
Electrical bonding is possible at the end faces. FIGS. 2(a) and 2(b) are cross-sectional views of the casing attached with the joint pieces of FIG. 1(b) and the joints thereof. Here, a top case 8 and a bottom case 9 forming the housing of an electronic device (for example, a television receiver) are shown.
This shows the case when connecting with. The top case 8 and bottom case 9 of the housing are both
It is made of conductive plastic as shown in FIG. 1(a). End face 1 of rib 19 formed on top case 8
0 and the end surface 11 of the rib 19 formed on the bottom case 9
The joining piece 4 according to the present invention is attached to. As shown in FIG. 2(b), when the joining piece 4 is inserted into the conductive plastic l, the protrusion 5 breaks through the skin layer 3, reaches the conductor part 2, and is electrically joined. On the other hand, a conductive contact body 7 is attached to the outside of the joint piece 4 via a conductive adhesive body 6. Here, a conductive double-sided tape is used as the material for the conductive adhesive body 6, but a conductive adhesive may also be used. Gaskets are used in which fibers are wrapped around the outside of urethane, but rubber surfaces are covered with wire mesh, elastomers made of silicone rubber with electrical conductivity, etc., which are generally used for the joints of metal casings. It is also possible to use a conductive gasket. As described above, in this embodiment, the conductive plastic conductor part 2 and the conductive contact body 7 formed by the top case 8 are held at the same potential, and the joint piece 4 in contact with each other is maintained at the same potential.
The conductor portion 2 made of conductive plastic forming the bottom case 9 is also held at the same potential. Therefore, since the top case 8 and the bottom case 9 are electrically connected,
The entire structure becomes a conductor and shields electromagnetic waves. FIG. 3 is a sectional view of a joint piece showing a second embodiment of the present invention. FIG. 3 shows a joint where the joint piece 4 according to this embodiment is attached to the conductive plastic 1, and corresponds to FIG. 2(b) of the first embodiment. The feature of this embodiment is that the metal surface 1 to which the conductive contact body 7 is attached
2 has a curved shape, this portion acts as a spring and strongly pinches the conductive plastic 1 that enters the inside of the joint piece 4 from the outside. Furthermore, since the protrusion 5 has a sharp tip and an acute angle formed inside the joint piece 4, it can be easily inserted into the end surface of the conductive plastic 1, but it can be removed after attachment. This results in a difficult structure. FIG. 4 is a perspective view of a joint piece showing a third embodiment of the present invention. In this embodiment, a suitable joining piece is provided when the end surface of the casing has a bent shape. That is, when the housing of an electronic device has a complicated shape and the end face of the housing to be joined forms a bent surface, in the joining piece 4 of FIG. cannot be inserted inside. In the joint piece 4 in this embodiment, a slit 14 is provided in the metal portion 13. That is, by sandwiching the conductive plastic 1 between both metal parts 13 attached to the conductive contact body 7, it can be sandwiched well even on a curved surface. Since protrusions are provided on the back side of these metal parts 13, they can be inserted inside the conductive plastic 1. Due to the function of these slits 14, the joining piece 4 can be bent in the direction in which it extends linearly. As a result, even if the end surface of the casing has a curved shape, it can be deformed into an arched shape and can be mounted. FIG. 5 is a perspective view of a joint piece protrusion showing a fourth embodiment of the present invention. In this embodiment, various shapes of the protrusions existing inside each joint piece 4 are shown. - As an example, as shown in FIG. 4, a case is shown in which the conductive contact body 7 is provided with a metal part and a protrusion is provided inside the metal part. FIG. 5(a) shows a structure in which a cut-and-raised portion 15 is provided on the inside of the joining piece. A cut and raised portion 15 is inserted inside the conductive plastic l. FIG. 5(b) shows a structure in which the tip of the raised cut 15 is made into a sharp shape to make it easier to tear the skin layer. FIG. 5(C) shows a structure in which the tip of the cut and raised portion 15 is further sharpened. FIG. 5(d) shows a structure in which the cut and raised portion 15 is shaped like a four-sided pyramid, and the skin layer is broken at the sharp point at the apex. FIG. 5(e) shows a structure in which only the tip of the cut and raised portion 15 is further bent inward to provide a protrusion 16. FIG. 5(f) shows a structure in which the raised cut 15 is shaped like a roof, and a plurality of protrusions 17 are provided at the ridge of the roof. FIG. 5(g) shows a joint piece equipped with a metal piece 13 having a slit 14 as shown in FIG. It is. In the case of FIG. 5(e), the protrusions 18 are provided on the metal piece at intervals of 10 mm. This distance is 2mm to 30mm
If it is narrower than 2 mm, it will be difficult to insert it into the conductive plastic, and if it is wider than 30 mm, the conductive bond will become thinner, making it impossible to ensure electrical connection. Further, the height of the protrusion is 2 mm. The second height is preferably 1 mm to 3 mm. because,
The thickness of the conductive plastic skin layer is 10 to 50 μm.
The thickness of the decorative coating on the metal casing is 0.5 to 0.8 m.
m, so in order to insert a protrusion there and ensure electrical connection, the height of the protrusion must be at least 1 mm. Furthermore, if the height of the protrusion is greater than 3 mm, it becomes difficult to insert the joining piece. Next, a case will be described in which electrical connection is made using a joining piece to a decoratively painted metal case. Metal cases are painted for the sake of appearance, but since the paint film is an insulating film, even if a conductive contact such as a conductive gasket is used at the joint of the members, it will have little effect. In order to improve the electrical connection, it was necessary to perform masking painting or to scrape off the surface coating after painting. When the joint piece according to the present invention is attached to the end face of a painted metal case, the protrusions present inside the joint piece destroy the coating film, which is an insulating layer, and create an electrical connection with the metal member.
It is possible to perform simple and effective electromagnetic shielding. FIGS. 6(a) and 6(b) are a sectional view of a terminal device to which the present invention is applied and a perspective view of its bottom case. Here, in order to maintain the aesthetic appearance of the device, a method is shown in which a joining rib 19 is provided inside the device and the joining piece 4 of the present invention is attached onto the rib 19. FIG. 7(a) shows a case where the joining piece 4 according to the present invention is attached to the end face of the casing. FIG. 7(b) shows the mounting tab 19 shown in FIG. 7(a) viewed from the bottom case 9 side. In FIGS. 6(a) and 6(b), 8 is a top case, 9 is a bottom case, 4 is a joint piece, and 19 is a rib. If the joining piece 4 is attached to the end face of the outer casing of the device, it is undesirable because it spoils the appearance, and the metal part is exposed to the outside, which tends to cause electrostatic damage. Therefore, here, ribs 19 for joining are provided inside the upper and lower cases 8. Get a junction. This makes it possible to provide electromagnetic shielding without damaging the appearance. FIGS. 7(a) and 7(b) are cross-sectional views of a joint piece and a casing to which the joint piece is attached, showing a fifth embodiment of the present invention. FIG. 7(a) shows a case where the joining piece 4 is attached to the end of the casing. 1 is a conductive plastic, 7 is a conductive contact, and 20 is an upper lid. The cross-sectional shape of the joint piece 4 is U as shown in FIGS. 1 to 3.
It is not limited to the shape of a letter or a U-shape, as long as it can sandwich the end face of the casing, and it is also possible to make it into an S-shape as shown in FIG. 7(a). In this case, contact is made on the side surface of the end surface of the housing. Also, S
Although a conductive contact 7 is attached to the character-shaped joint piece 4, the conductive contact 7 does not necessarily have to be present. That is, even if the conductive contact body 7 is not present, it is also possible to ensure electrical connection with the metal portion of the joining piece 4. FIG. 7(b) shows a cross section of the entire casing of FIG. 7(a), which can be used for the joint part of the upper lid 20. FIG. 8 is a structural perspective view of a protrusion of a joint piece showing a sixth embodiment of the present invention. In FIG. 8, the joint piece 4 attached to the conductive contact body 7 is shown, and a plurality of cut and raised portions 5 are provided on the joint piece 4. The protrusion is provided so that the angle formed between the cut and raised portion 5 and the inner metal surface of the joint piece 4 is an obtuse angle at the insertion opening of the joint piece 4. In this case, the joint piece 4 is easily inserted into the end of the casing, but it is difficult to remove it. However, since the protrusion has a weak force of digging into the end surface of the casing when inserted, it is necessary to remove the skin layer or make up the surface. Less effective against paint peeling. Further, the angle formed between the cut and raised portion 5 and the inner metal surface of the joint piece 4 is provided so that the insertion opening of the joint piece 4 forms an acute angle. In this case, the skin layer can be easily removed or the decorative coating can be peeled off when the protrusion is inserted, but it becomes difficult to remove the joint piece 4 after insertion. In order to compensate for the drawbacks of both, the angle formed by the cut and raised portion 5 and the inner metal surface of the joint piece 4 is alternated between protrusions where the insertion opening of the joint piece 4 has an obtuse angle and protrusions where the angle is acute. It is arranged in The obtuse-angled protrusion prevents the joining piece 4 from falling off after insertion, and the acute-angled protrusion is effective for removing the skin layer or peeling off the decorative coating. As a result, the joint piece 4 can be made to have a structure that ensures conduction and is difficult to remove.

【Effect of the invention】

As explained above, according to the present invention, electrical connection can be easily secured by attaching a joint piece having a protrusion to the end face of conductive plastic or the end face of a painted metal case. Electromagnetic wave shielding of the casing can be performed by a method that

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a joint piece and conductive plastic showing a first embodiment of the present invention, FIG. 2 is a cross-sectional view of a casing and a joint part to which the joint piece of FIG. 1 is applied, and FIG. FIG. 4 is a cross-sectional view of a joint piece showing a second embodiment of the invention, FIG. 4 is a perspective view of a joint piece showing a third embodiment of the invention, and FIG. 5 shows a fourth embodiment of the invention. Figure 6 is a cross-sectional view of a housing to which the present invention is applied and a perspective view of a bottom case. Figure 7 is a diagram showing the shape of a protrusion of a joint piece, and Figure 7 is a joint piece showing a fifth embodiment of the present invention and a view to which it is applied. FIG. 8 is a cross-sectional view of the housing and a perspective view of the protrusion arrangement of the joint piece showing the sixth embodiment of the present invention. 1: conductive plastic, 2: conductor portion of conductive plastic, 3. Conductive plastic skin layer, 4: Joint piece, 5: Projection, 6: Conductive adhesive, 7: Conductive contact, 8 Ni dot case, 9: Bottom case, 10 Ni dot case end face, 11: Bottom case end face, 12 : bent surface of joint piece, 13 metal part of joint piece, 14: slit of joint piece, 15: cut and raised part, 16: bending of cut and raised part,
17: Protrusion of cut and raised part, 18: Bending of metal piece, 19
: Rib, 20: Upper lid of the housing. Representative Patent Attorney Masatoshi Isomura ← Pregnancy (a) Figure Figure (Part 1) Figure (Part 2) Figure (Part 1) (a) Figure (Part 2) Figure

Claims (4)

[Claims] 1. In a shield structure that conductively connects the end face of an electronic device case, the inside is made of a metal case or conductive plastic material and the outside is covered with an insulating coating or an insulating skin layer. By providing a joining piece to which a conductive contact body is attached to the outside, and inserting the joining piece into the metal case or conductive plastic material on the end face of the housing, the protrusion will pierce into the inside of the conductive plastic. A shielding structure for an electronic device, characterized in that the conductive contact members are electrically connected to each other, and the conductive contact members are electrically connected to each other to shield the housing from electromagnetic waves. 2. In the shielding structure for an electronic device according to claim 1, the joining piece has a curved metal surface that matches the outer shape of the conductive contact body, and a conductive plastic or metal case on the end surface of the housing from both sides of the metal surface. A shielding structure for an electronic device, comprising a U-shaped member having a sandwiching shape, and a protrusion that is attached to the tip of the member and pierces into the conductive plastic or metal case on the end face of the housing. 3. In the shielding structure for an electronic device according to claim 1, the joining piece is attached to a conductive contact body and is attached to the conductive contact body, and when sandwiching the conductive plastic member or metal case on the end face of the casing from the outside. A shield structure for an electronic device, comprising: a metal part provided with a plurality of slits for bendability; and a protrusion provided inside the metal part. 4. 2. The shielding structure for electronic equipment according to claim 1, wherein the connecting piece includes a conductive contact body, and a conductive plastic member or metal attached to the conductive contact body, and a conductive plastic member or metal on the end surface of the housing in one of the U-shaped grooves. A shield structure for an electronic device, comprising a metal member having an S-shape into which a case is inserted, and a protrusion attached to the inside of the metal member.