JPS61276400A - Shielding case - 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 [Field of Industrial Application] The present invention relates to a shield case, and particularly to a shield case suitable for use in a high frequency circuit and capable of minimizing the area required for installation.

[Prior art and its problems]

Generally, when a shield case is attached to a printed circuit board to eliminate interference between circuits, screws are usually used for manufacturing and maintenance reasons. At this time, the edge of the shield case and the opposing surface (for example, a printed circuit board pattern) are electrically connected. but,
In reality, the edge and the opposing surface cannot be perfectly flat, and there is a limit to the tightening pressure, so the actual contact points are only about a few over the entire contact surface. For this reason,
Particularly when used in high-frequency circuits, there is a drawback that a sufficient shielding effect cannot be obtained.

Therefore, a method conventionally employed to ensure conduction between the shielding plate and the substrate will be explained with reference to FIGS. 9 to 12. The shield case 101 shown in FIG.
02-a=Therefore, it can be tightened to the printed board 103. Shield case 104 shown in FIG.
is a conductive gasket 10 made of conductive rubber, wire mesh, etc.
5 is sandwiched between the printed board 106 and tightened with screws 107K. The shield case 108 shown in FIG. 11 is provided with a groove TOSB, into which a conductive gasket 109 is fitted, the gasket contacts the printed board 110, and the screws 111 tighten them. ing. The shield case 112 shown in FIG.
In the above conventional example, the contact surfaces 101a and 104a are fastened onto the contact surfaces 101a and 104a.

108a width Wl, W2. It is necessary that W3 is wide and that the printed pattern (not shown) facing the contact surface is wide.
40 width W4 was very wide. Therefore, a large amount of space is required for shielding, and especially when many small shield cases are arranged side by side on a printed circuit board, the area of the printed pattern used for the circuit part is severely restricted, and it is difficult to improve the degree of integration and reduce the size of equipment. The drawback was that it was extremely difficult. Second, shield case 10
1°104.108. Since l12 is a thick metal plate, processing costs are high, and it also requires a conductive gasket)10
Since the number of man-hours in the assembly process increases due to the insertion of the 5.degree. At the same time, there is a drawback in that maintenance services are difficult to disassemble and assemble.

Thirdly, shield case 101゜104.108,11
2 has low earthquake resistance because of its weight, and especially the shield cases 104 and 108 are conductive gaskets) 105
, 109 changes over time, the contact pressure changes and conduction becomes insufficient, resulting in low reliability.

[Purpose of the invention]

The present invention has been made in order to eliminate the drawbacks of the prior art described above, and its purpose is to arrange a large number of metal pieces of about several millimeters between the shielding plate and the substrate to ensure reliable The purpose of the present invention is to provide a shielding case that makes multi-point contact and provides a sufficient shielding effect even in a high frequency range.

Another object is to form a casing by using a very thin metal plate as a shielding plate, which has a sufficient shielding effect and has the necessary mechanical strength, and to For example, by adjusting K such that a multi-point contact is made with a contact width of less than 1 mm).

The purpose is to save space for installing the shield case, make it possible to narrow the width of the printed pattern for connection to the shield case, and increase the degree of integration per printed board.

Another purpose is to reduce processing costs by using a thin metal plate for the shielding plate, and at the same time to improve earthquake resistance by reducing the weight of the shielding case. Another purpose is to simplify the assembly process and maintenance work by using a contact piece to contact the shielding plate and the board so that the number of fasteners such as screws is minimized. Another purpose is to use a metal material for the contact piece.

The purpose is to prevent changes in contact pressure over time, such as when using a conductive rubber gasket, and to improve reliability. Another purpose is to shorten the conduction path between the shield plate and the board by directly connecting the edge of the shield plate and the board using the contact piece. It is an object of the present invention to provide an installation method that eliminates the need for electrical connection to parts other than the parts and facilitates the assembly work.

[Summary of the invention]

In short, the present invention includes a shielding plate attached to a substrate and a contact piece made of an elastic metal material, and the contact piece is brought into contact with an edge of the upper shielding plate and the substrate, and is not attached to the substrate. Embodiments of the Invention The present invention will be described below based on embodiments shown in the drawings. As shown in the figure, the shield case l according to the present invention is
It includes a shielding plate 2 and a contact piece 3. The shielding plate 2 is formed in the shape of a casing, and the contact piece 3 is fixed with a rivet 4.

As shown in FIG. 2, the contact piece 3 consists of an L-shaped strip 5 and a tongue 6. The diaphragm portion 5 is made of a thin band-shaped metal having elasticity, and the tongue-like pieces 6 are formed integrally extending from one side 5a of the band-like portion, and a plurality of tongue-like pieces 6 are arranged side by side. The angle θ between the band 5 and the tongue 6 is a near right angle, and each tongue 6 is twisted in the direction of the arrow.

Next, FIGS. 3 and 4 show a state in which the shield case l is attached to a printed board 8, which is an example of a board. A printed pattern 9 is pasted on the printed board 8, and a lead case l is fastened to the printed board 8 with screws 10 and nuts 11, and the tongue 6 is inserted into the printed pattern 9. In this state, the tongue 60
The surface 6s is non-parallel and non-perpendicular to the printed board 8, and comes into contact with the edge 2a of the shielding plate 2 and the printed pattern 9 at a constant angle. That is, the contact point 6a of the tongue-like piece 6 contacts the printed pattern 9, and the contact point 6a
b is in contact with the edge 2a.

Next, FIGS. 5 to 8 show other embodiments of the contact piece 3. The contact piece 13 includes a tongue-like piece [4, and a corner part 14a of the tongue-like piece is attached to a substrate (not shown) at a corner part 14i.
) on the edge of the shield plate (not shown).

Each is busy making contact at a certain angle. Contact piece 1
5 is provided with a curved tongue-like piece 16 such that the top part 16a of the tongue-like piece contacts the substrate (not shown) and the end part 16b contacts the edge of the shielding plate (not shown). It has become. Similarly, the end 18a of the tongue-like piece 18 of the contact piece 17
and end portion tsb are adapted to contact a substrate (not shown) and an edge (not shown) of the shielding plate, respectively.

The contact piece 19 shown in FIG. 8 includes a support member 20 having a U-shaped cross section and a tongue-like piece 21. The support member 20 is
The tongue-shaped piece 21 is fitted into the shielding plate 22 as shown by arrow C.
comes into contact with the edge 22a and the substrate (not shown).

The present invention is constructed as described above, and its operation will be explained below. Referring to FIG. 3 and FIG. 4, when attaching the shield case l to the printed board 8, a tightening force is applied in the direction of arrow B. The tongue-like piece 6 is attached to the edge of the shield plate 2 2a and the printed board 8, it deforms in response to the tightening force shown by the arrow B, and generates an elastic repulsive force.The repulsive force causes the contact point 6a of each tongue-like piece 6 to contacts the printed pattern 9, and the contact point 6b
contacts the edge 2a. Therefore, the length of the conductive path from the edge 2a to the printed pattern 9 is the length between the contact 6a and the contact 6.
Since it is equal to the distance from b, the width W6 of the tongue-shaped piece 60 does not exceed the width W6 at the maximum (about several millimeters), and by reducing the value of the width W6, it is possible to make the conduction path extremely short.

In this way, between the shield case l and the printed pattern 9, the edge 2
Stirrup multi-point contact is obtained over the entire circumference of a, and grounding necessary for shielding in the high frequency range is performed.

At this time, as shown in FIG. 1, the length Ll of the tongue-like piece 6
is almost equal to the height Ws of the shielding plate 2 (approximately 1 mm), so the space required for mounting the shielding case l is extremely small (and the width of the printed butter can also be made narrower).

Furthermore, the surface 5b of the strip portion 50 and the surface 2b of the shielding plate 20 facing the core do not necessarily need to be electrically connected, and the quality of conductivity does not matter. Installation with 3 is done by welding.

It is possible to select any method such as rivets or adhesives. Further, like the contact piece 19 shown in FIG. 8, the supporting member 20 can be fixed by fitting it into the shielding plate 22, or by simply inserting it between the substrate and the shielding plate.

The contact pieces 13, 15 and 17 shown in FIGS. 5 to 7 act in the same manner as the contact piece 3, so a detailed explanation will be omitted.

In addition, in the above embodiment, the case where the shield case l is attached to a printed board is explained, but of course the case is not limited to this, and the application can also be applied to a flat shield cover or a connecting part between shield cases. can.

〔Effect of the invention〕

The present invention is constructed and operates as described above, and since a large number of metal pieces of several millimeters are arranged between the shielding plate and the substrate, reliable multi-point contact is made, and high frequency The effect of sufficient shielding can be obtained even in the area. In addition, the casing is formed by using a very thin metal plate as the shielding plate, which has a sufficient shielding effect and has an essential mechanical strength, and the thickness of the metal plate (
Since multi-point contact is made with a contact width of (for example, 1 mm or less), the space where the shield case is installed is reduced, the width of the printed pattern for connection with the shield case is narrowed, and the circuit area per printed board is reduced. The effect is that it becomes possible to increase the degree of integration. Furthermore, since a thin wire mesh plate is used for the shielding plate, processing costs are reduced, and at the same time, the shielding case is made lighter and earthquake resistance is improved. Further, since a contact piece is used for contacting the shielding plate and the board, the number of fasteners such as screws can be minimized, and the assembly process and maintenance operations can be simplified. Further, since metal is used as the material of the contact piece, changes in contact pressure over time, which would occur when Skate is used as the conductive rubber, are prevented, and reliability is improved. In addition, since the edge of the shielding plate and the board are directly connected using the contact piece, the conduction path between the shielding plate and the board can be shortened, and the contact piece can be connected to other parts of the shielding plate other than the wires. The present invention has extremely high industrial utility value because it eliminates the need for electrical connection to the device and allows assembly work and installation to be performed using the easiest method.

[Brief explanation of the drawing]

1 to 8 relate to embodiments of the present invention, FIG. 1 is a perspective view of a shield case, FIG. 2 is a perspective view of a contact piece according to the first embodiment, and FIGS. 3 and 4 are FIGS. 5, 6, 7, and 8 are perspective views of contact pieces according to other embodiments; 9 to 12 are shield cases related to conventional examples? FIG. 1.101.104.10B, 112: Shield case, 2.22: Shielding plate, 3.13.16.17.19: Contact piece, 5: Band-shaped part 6.14.16.18.21: Tongue-shaped piece, 8.103.1
06.11G, 113: A printed board that is an example of a board.

Claims (1)

[Scope of Claims] 1. A shielding plate attached to a substrate and a contact piece made of an elastic metal material, the contact piece contacts an edge of the shielding plate and the substrate, and the contact piece makes contact with the edge of the shielding plate and the substrate. A shield case characterized in that at least a portion of the shield case has non-parallel and non-perpendicular surfaces. 2. The contact piece includes a band-shaped portion attached to the shielding plate;
The shield case according to claim 1, further comprising a tongue-like piece integrally extending from the band-like part. 3. The shield case according to claim 2, wherein the tongue-shaped piece is formed to extend in an L-shape from the band-shaped part.