JP2001144488A - Box body structure of module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a box body structure of a module that obtains high frequency shield effect and has lightweight properties suitable for a portable communication apparatus while being produced at low cost. SOLUTION: The box body structure of the module is constituted by housing a circuit board 5, containing a high frequency circuit part, in a case 4 that is formed by sectioning a case main body 2, which is formed by thin plate working and opens upward, with a partitioning plate 3, and covering the upper part of the case 4 with a cover 6. The cover 6 is constituted with a cover main body 60, a thin elastic member 61 and a metal thin plate 62 as main bodies. The elastic member 61 is placed on a top surface of the cover main body 60, and further the thin plate 68 is placed on a lower surface of the elastic member 61. The lower surface 620 of the thin plate 62 is brought into contact with a peripheral wall part 20 of the case main body 2 and upper end surfaces 22 and 32 of the partitioning plate 3 when the upper part of the case 4 is covered with the cover 6 for electromagnetic shielding.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a housing structure of a module containing a circuit board including a high-frequency circuit such as an RF circuit, and more particularly, to a high-frequency shielding function used for portable communication equipment such as a portable telephone. The present invention relates to a housing structure of a provided module.

[0002]

2. Description of the Related Art Portable communication devices, such as mobile phones, have rapidly become widespread in recent years along with drastic reductions in call charges and expansion of call areas. In such a portable communication device, a measure for protecting a high-frequency circuit portion performing a communication function from radiated electromagnetic noise emitted from a digital circuit portion mounted with a high operating frequency electronic component such as a processor and an LSI, so-called EMI ( Electro Magnetic I
As one of the countermeasures, a circuit board including a high-frequency circuit is housed in a metal module having a high-frequency shielding function.

[0003] As a prior art relating to such a module, those shown in FIGS. 3 and 4 are known.

As shown in FIGS. 3 and 4, a module 10 includes a circuit including a high-frequency circuit section (not shown) in an aluminum case 12 having a partition plate 11 formed therein by cutting. A circuit board 13 having various functions such as a board is fixed with a plurality of screws 14, and furthermore, upper surfaces 110 and 120 of the partition plate 11 and the peripheral wall of the case 12 are fixed.
The EMI gasket 16 made of a metal wire mesh is fitted and mounted in the groove 15, and an aluminum cover 17 is fixed from above by a screw 18.

In the module 10 having the above-described structure, when the cover 17 is fixed with the screws 18, electrical conduction between the cover 17 and the case 12 is ensured via the EMI gasket 16, and a shielding effect against high frequency is obtained. It is made to be able to be done.

[0006]

By the way, the conventional module 10 has the EMI disposed in the groove 15 as described above.
Since the gasket 16 ensures electrical continuity between the case 12 and the cover 17, the peripheral wall of the case 12 and the partition plate 11 need to have a sufficient thickness for providing the groove 15, and the thickness of the case is reduced. Had limitations. Therefore, since the case 12 is thick and heavy, it is not preferable for a portable communication device for which reduction in size and weight is desired. Further, since the case 12 is manufactured by the cutting process, the manufacturing cost has to be increased. Further, mounting the EMI gasket 16 in the groove 15 is very troublesome.

Therefore, an object of the present invention is to provide a sufficient high-frequency shielding effect without the need for an EMI gasket which takes a lot of time for mounting, and has a light weight suitable for a portable communication device and a low weight. It is an object of the present invention to provide a module housing structure that can be produced at low cost.

[0008]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention includes a high-frequency circuit portion in a case formed by sheet metal working and having a case body defined by a partition plate inside a case body opening upward. A housing structure of a module that accommodates a circuit board and covers an upper part of the case with a cover, wherein the cover mainly includes a cover body, a thin elastic member, and a metal thin plate, and the cover body The elastic member is arranged on the top surface of the elastic member and the thin plate is arranged on the lower surface of the elastic member, and when the upper part of the case is covered with the cover, the lower surface of the thin plate and the peripheral wall of the case body and It is characterized in that the upper end surface of the partition plate is brought into contact with the partition plate to perform electromagnetic shielding.

The thin plate has flexibility and toughness,
A hard metal that does not locally deform is preferable, and among these, a thin plate made of phosphor bronze is particularly preferable. The thickness of the thin plate is preferably 0.2 to 0.5 mm. If it is less than 0.2 mm, local deformation will occur during screwing, etc.
If it exceeds m, flexibility is lost and sufficient adhesion to the case or the partition plate cannot be obtained.

The elastic member may have a thickness of 1 to 3.
mm synthetic rubber sheets are preferred. If it is less than 1 mm, no elastic effect can be obtained, and if it exceeds 3 mm, it is not suitable for reduction in size and weight. Examples of the material of the synthetic rubber include neoprene rubber and silicone rubber, and silicone rubber is particularly preferable. In addition, synthetic rubber to which an electromagnetic wave absorbing powder such as an Fe-based microcrystalline magnetic material, a ferrite-based magnetic material, or an Fe-Si-Al alloy has been added can be used. The shielding effect can be further enhanced.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the accompanying drawings. Note that the present invention is not limited to this embodiment.

FIGS. 1 and 2 show a module to which a module housing structure according to an embodiment of the present invention is applied. In these figures, reference numeral 1 indicates a module.

As shown in FIGS. 1 and 2, the module 1 has a case body 2 formed by pressing and having a case body 2 defined by a metal partition plate 3 inside a case body 2 opening upward.
And a circuit board 5 including a high-frequency circuit unit housed in the case 4 and a cover 6 covering the upper part of the case 4.

The case body 2 and the partition plate 3 are each made of a separate member made of aluminum having a thickness of 1 to 2 mm, and these are bonded by welding. Piece portions 21 and 31 having screw holes corresponding to metal screws 7 for screwing cover 6 on peripheral wall portion 20 and partition plate 3 of case body 2.
Are formed by bender processing. The upper end surfaces 22, 32 of the peripheral wall portion 20 and the partition plate 3 of the case body 2 and the upper end surfaces 23, 33 of the piece portions 21, 31 are formed substantially flush. A nut 24 is fixed to the bottom of the case body 2 by welding.
It is made to be able to screw with 5.

The cover 6 includes a cover body 60, a synthetic rubber sheet 61 adhered to the top surface thereof, a phosphor bronze plate (a thin metal plate) 62 adhered to the synthetic rubber sheet (thin elastic member) 61, Is mainly composed. In the present embodiment, the cover main body 60 is made of aluminum having a thickness of 1 to 2 mm, and the synthetic rubber sheet 61 is formed of a 2 m thick.
m of silicone rubber, and the thickness of the phosphor bronze plate 62 is 0.3 mm.

In the case structure of the module 1 having the above structure, when the cover 6 is screwed with the screw 7 and the upper part of the case 4 is covered with the cover 6, the lower surface 62 of the phosphor bronze plate 62
0, peripheral wall 20 of case body 2 and upper end surface 2 of partition plate 3
Due to the elastic force of the synthetic rubber sheet 9, the synthetic rubber sheets 2 and 32 are almost completely adhered to each other, and electrical continuity between them is ensured and a high-frequency shielding effect is obtained. Further, since the cover 6 is screwed to the case main body 2 and the partition plate 3 with the screws 7, electrical conduction between them is ensured, and the cover 6 itself also functions as a shield.

As described above, according to the housing structure of the module 1 according to the present embodiment, the EMI which is troublesome to mount.
Since a gasket is not required, there is no need to provide grooves on the upper surfaces of the case body and the partition plate as in the related art. Therefore, the thickness of the case body and the partition plate can be reduced, and the weight can be reduced accordingly. Further, since the case main body and the partition plate can be made thin, the case main body can be manufactured by sheet metal processing without cutting, whereby the manufacturing cost can be significantly reduced.

In the present invention, as in the above embodiment, it is preferable to use a phosphor bronze plate as the metal thin plate, but the present invention is not limited to this. As long as it is a hard metal thin plate which has toughness and does not locally deform, a thin plate made of another material, for example, stainless steel, nickel silver (Cu-Ni-Zn alloy), or Be-Cu alloy may be used. it can.

Further, in the present invention, as in the above embodiment, the cover is preferably formed of a metal material such as aluminum. However, the elastic member is contracted by the above-mentioned screwing to form a thin metal plate. Other materials such as plastics, for example, can be used as long as they have strength enough to completely adhere to the case body and the partition plate. In this case, the weight of the module can be further reduced.

[0020]

According to the module housing structure of the present invention, a sufficient high-frequency shielding effect can be obtained without the need for an EMI gasket which is troublesome to mount.
Moreover, it can be produced at a low cost and light weight.

[Brief description of the drawings]

FIG. 1 is a plan view, partially cut away, of a main part of a module housing structure according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along the line AA of a main part of FIG.

FIG. 3 is a plan view of a main part of a conventional module in which a part of a housing structure is cut away.

FIG. 4 is a cross-sectional view of a main part of FIG.

[Explanation of symbols]

1: module, 2: case body, 20: peripheral wall, 2
2, 32: upper end surface, 3: partition plate, 4: case, 5: circuit board, 6: cover, 60: cover body, 61: synthetic rubber sheet (thin elastic member), 62: phosphor bronze plate (made of metal) , Lower surface: 620.

Claims (2)

[Claims] 1. A circuit board including a high-frequency circuit section is accommodated in a case defined by a partition plate inside a case main body formed by sheet metal processing and opening upward, and the upper part of the case is covered with a cover. A housing comprising a cover main body, a thin elastic member, and a metal thin plate, wherein the elastic member is disposed on a top surface of the cover main body, and The thin plate is disposed on the lower surface of the member, and when the upper part of the case is covered with the cover, the lower surface of the thin plate is brought into contact with the peripheral wall of the case body and the upper end surface of the partition plate to perform electromagnetic shielding. A module housing structure characterized in that: 2. The module structure according to claim 1, wherein the thin plate is a phosphor bronze plate.