JPS63158898A - Construction of shielding radio frequency circuit 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] Overview A plurality of four high frequency functional circuits are mounted on a board, each high frequency functional circuit is separated by a ground pattern, and
When mounting and fixing a shielding case having a vertical wall portion corresponding to the ground pattern on the board to provide a shielding structure, apply solder, for example, to a plurality of desired locations on the end surface of the vertical wall portion of the shielding case that contacts the grounding pattern. A shield structure for a high frequency circuit device, characterized by having a convex portion formed from a soft metal such as.

With this structure, a reliable shield structure can be achieved and the productivity of the shield structure can be improved.

The present invention relates to a shield structure for a high frequency circuit device that prevents electromagnetic interference between the high frequency functional circuits in a high frequency circuit device in which a plurality of high frequency functional circuits are mounted on the same printed circuit board.

Wireless communication devices are used in car phones, mobile phones, cordless phones, personal radios, etc., and recently, with the effective use of radio waves and multi-access communication, quasi-microwave frequency bands have been adopted as wireless frequency bands. High frequency bands around 1 GHz, called bands, have come into use. Therefore, in the circuit configuration of wireless communication equipment, prevention of electromagnetic interference between each function circuit has become an important issue. In addition, the digitalization of the social environment has progressed in a wide range of areas, and ftfii communication between various electronic devices, including wireless communication devices,
There is a need to prevent interference, and unnecessary radio wave radiation from various devices is regulated, and for this reason, electromagnetic shielding of high frequency circuits has become an important issue.

Figure 3 shows a partially cutaway exploded perspective view of the shield structure of a conventional high frequency circuit device.
Although component mounting and wiring patterns are omitted, a plurality of high frequency functional circuits 12 are mounted, and each high frequency functional circuit 12 is isolated by a conductive ground pattern 14. The ground pattern 14 is provided with a plurality of through holes 16 for electrically connecting the front and back sides of the printed circuit board 10, and further has mounting holes 18 formed at a plurality of locations. Reference numeral 20 denotes a shield case made of aluminum alloy or the like, which is connected to the ground pattern 1 of the printed circuit board 10.
Each high frequency functional circuit 12 is
A shield space 24 corresponding to the above is formed. Screw holes corresponding to the mounting holes 18 of the printed circuit board 10 are formed in the vertical wall portion 22 of the shield case 20, and the shield case 20 is fixed onto the printed circuit board 10 with screws (not shown).

FIG. 4 is a sectional view taken along the line IV-IV in FIG.
A) and (B) show different structures, and these structures allow the shield case 20 to be connected to machine #1 of the printed circuit board 10.
Good electrical contact is achieved so that the potential is the same as that of the ground pattern 14 divided by circuit. Figure 4 (A
), a long groove 23 is formed on the end face of the vertical wall portion 22 of the shield case 20, a conductive gasket 26 such as a metal mesh gasket or a conductive rubber gasket is fitted into the long groove 23, and the ground pattern 14 and the shield case are connected to each other. 20 to obtain good electrical contact. Also, Figure 4 (
In the structure B), solder bumps (hereinafter referred to as solder bumps) are formed on the plurality of holes 16 of the 7-spat pattern 14.

The solder bump 28 is, for example, a ball solder 29 with a high melting point.
is formed by wrapping it with low melting point solder 30. This structure utilizes the flexibility of solder to ensure reliable electrical contact between the ground pattern 14 of the printed circuit board 10 and the shield case 20.

While the invention is about to be decided.

However, the shield case 20 as shown in FIG. 4(A)
In a structure in which an IJffi gasket 26 such as a metal mesh gasket or a conductive rubber gasket is interposed at the contact portion between the ground pattern 14 of the printed circuit board 10 and the ground pattern 14 of the printed circuit board 10, the shield case 20 is shaped to structurally hold the conductive gasket 26. or I
Shield case 20 at the bent part of W gasket 26
There is a problem in that the space factor of the high frequency circuit device deteriorates because of the shape restriction. Furthermore, since the conductive packing 26 must be incorporated into the groove 23,
In addition to poor productivity, there are other problems such as increased costs due to inclusions such as conductive packing.

Further, as shown in FIG. 4(B), the shield structure in which the solder bumps 28 are formed on the ground pattern 14 of the printed circuit board 10 is designed to weld the formed solder bumps with solder for mounting circuit components. There is a problem in that it is necessary to use solder with a high melting point. Further, there is a problem in that the uniformity of the shape of the solder bumps 28 and the alignment of the bumps are difficult, and especially when it is necessary to provide solder bumps on both sides of the printed circuit board, there are many more restrictive conditions, resulting in extremely poor productivity.

The present invention has been made in view of these points, and an object of the present invention is to provide a shielding structure for a high frequency circuit device that is highly productive and can achieve reliable electromagnetic shielding.

A shield having a plurality of high frequency functional circuits 12 mounted on a substrate 10 for conducting a test, each high frequency functional circuit 12 being separated by a ground pattern 14, and having a vertical wall portion 22 corresponding to the ground pattern 14. A case 20 is mounted and fixed on the board 10. In the present invention, in order to provide an electromagnetic shielding structure for a high frequency circuit device, the ground pattern 1
Vertical wall end surface 22a of shield case 20 that contacts 4
Convex portions 34 made of soft metal are placed at multiple desired locations on the
It is characterized by having the following.

1-1 Since the convex portions 34 formed at multiple locations on the vertical wall end surface 22a of the shield case 20 are made of soft metal such as solder, the shield case 20 is connected to the printed circuit board 10.
When the shield case 20 is fixed to the top by screws or the like, the convex portion 34 is appropriately crushed to achieve reliable electrical contact between the shield case 20 and the ground pattern 14 of the printed circuit board 10.

By appropriately selecting the distance between each convex portion 34, a complete electromagnetic shielding structure for the high frequency circuit device can be provided.

BEST MODE FOR CARRYING OUT THE INVENTION Below, the present invention will be explained in detail based on embodiments shown in the drawings.

FIG. 1 shows an exploded perspective view of one embodiment of the shielding structure of a high-frequency circuit device according to the present invention, and the same components as the conventional shielding structure shown in FIG. 3 will be described with the same reference numerals. I'll decide.

Although component mounting and circuit patterns are omitted on the printed circuit board 10, a plurality of high frequency functional circuits 12 are mounted, and each high frequency functional circuit 12 is connected to the ground pattern 1.
It is isolated by 4. The ground pattern 14 is provided with a plurality of through holes 16 for electrically connecting its front and back sides, and also has a plurality of mounting holes 18 formed therein.

Reference numeral 20 denotes a shield case, which is made of, for example, an aluminum alloy, or by vapor-depositing metal on the surface of a resin mold. The shield case 20 is provided with a vertical wall portion 22 corresponding to the ground pattern 14 of the printed circuit board 10 , and this vertical wall portion 22 forms a plurality of shield spaces 24 corresponding to the high frequency functional circuit 12 .
is formed. A plurality of screw holes 32 corresponding to the mounting holes 18 of the printed circuit board 10 are provided in the vertical wall end surface 22a of the shield case 20, and solder bumps 34 are formed at a plurality of desired locations.

In order to mount and fix the shield case 20 on the printed circuit board 10, it can be fixed by inserting a screw (not shown) into the mounting hole 18 and tightening it into the screw hole 32. When the shield case 20 is tightened and fixed on the printed circuit board 10 with screws in this way, the solder bumps 34, which are preferably made of low melting point solder, are slightly crushed and deformed, causing the ground pattern 14 of the printed circuit board 10 and the shield case to be crushed and deformed. Reliable electrical contact with the vertical wall end surface 22a of 20 can be achieved. According to this structure,
Even if the printed circuit board 14) is bent, distorted, or has surface irregularities, reliable electrical contact is achieved at the desired points.

The cross-sectional shape at the solder bump 34 is shown in Figure 2 (A).
Any of the structures shown in ~(C) can be adopted. Second
In the structure shown in Figure (A), a hole 36 is formed in the end surface 22a of the vertical wall portion of the shield case 20, and by dipping the solder with this end surface 22a facing downward, the solder swells at the hole 36 part due to the surface tension of the solder itself. solder bump 34
can be formed. FIG. 2(B) shows another actual embodiment, in which a recess 3 of the solder pool is formed around a small protrusion.
5, and also solder bump 3 by solder dip.
4'. FIG. 2C shows yet another embodiment, in which a solder bump 34'' is formed by filling a relatively shallow hole 37 formed in the end face of the vertical wall portion 22 with ball solder.

The solder material is low melting point 5nPb eutectic solder,
Alternatively, In-based solder, which is much softer than eutectic solder, can be used. Further, the bump molding position can also be molded simultaneously when molding the shield case.

As mentioned above, the shield structure of the present invention has a protrusion made of soft metal such as solder on the shield case side, so there are no restrictions on the selection of soft metal materials, and productivity can be improved. This has the effect of achieving a reliable shield structure. Therefore, when mounting the shield case by pressing it onto the printed circuit board, it becomes more flexible! 5. Materials with high adhesion properties can be selected. Furthermore, since the protrusion can be formed at a desired location on the shield case, it is possible to form the protrusion uniformly at an accurate position. .

[Brief explanation of the drawing]

FIG. 1 is an exploded perspective view of an embodiment of the present invention, and FIG. 2 is a sectional view taken along the ■-π line in FIG.
) and (C) respectively show different embodiments. FIG. 3 is a partially cutaway exploded perspective view of a conventional shield structure, and FIG. 4 is a cross-sectional view taken along the line IV-rV in FIG.
(B) shows different shield structures. DESCRIPTION OF SYMBOLS 10... Printed circuit board, 12... High frequency functional circuit, 14... Earth pattern, 16... Through hole, 18... Mounting hole, 20... Shield case, 22... Vertical wall part , 22a... Vertical wall end surface, 24... Shield space, 32... Screw hole,
34.34', 34"... solder bump, 35...
・Concavity, 36.37...hole. 14: Turn to ground 16: Through hole 20: Shield space 22: GL straight wall section 34: Solder) -IN! 11'' side view Figure 2 20: Shield case 22: Do direct g! sound F I's shield for laziness/sai nose sana- Figure 3 14: Earth pattern 16: Thru o, -ru Figure 3 ■-■￥ M″ concave figure 4

Claims (1)

[Claims] A plurality of high-frequency functional circuits (12) are mounted on a substrate (10), and each high-frequency functional circuit (12) is separated by a ground pattern (14).
In the shield structure of a high frequency circuit device in which a shield case (20) having a vertical wall portion (22) corresponding to the vertical wall portion (22) is mounted and fixed on the substrate (10), the shield case (20) is in contact with the earth pattern (14). ) A shield structure for a high frequency circuit device, characterized in that convex portions (34) formed from a soft metal are provided at a plurality of desired locations on an end surface (22a) of a vertical wall portion.