JP2008124259A - Electromagnetic-wave shield housing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To miniaturize an electromagnetic-wave shield housing without damaging its electromagnetic-wave shield effect, in the electromagnetic-wave shield housing so constituted as to be able to store electronic components therein and suppress the inputting/outputting of the electromagnetic wave to/from the electronic components. <P>SOLUTION: Fig. 3 shows such a state that in an electromagnetic-wave shield housing of an embodiment a printed wiring board 90 is so fastened onto a spacer 18 by a screw 91 as to be covered with a cap portion 20. A rubber sheet 22 filled with a ferrite is stuck on the surface of the inner wall of the cap portion 20, and since a hole portion 24 is drilled in the opposite portion to the spacer 18 with respect to the rubber sheet 22, the head portion of the screw 91 is engaged with the hole portion 24. Since the head portion of the screw 91 is made of a metal, all the electromagnetic waves intended to pass through the hole portion 24 are reflected by the head portion of the screw 91, and the rubber sheet 22 absorbs the electromagnetic wave. Also, since the head portion of the screw 91 is engaged with the hole portion 24, even though the rubber sheet 22 is not thinned extremely, any unavailable space present in the inside of the electromagnetic-wave shield housing can be reduced effectively. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a housing configured to be able to store an electronic component, and more particularly, to an electromagnetic shielding housing capable of suppressing electromagnetic waves from entering and exiting the electronic component.

Conventionally, electromagnetic waves are radiated from electronic components such as CPUs and ICs to affect surrounding circuits, or electromagnetic waves radiated from surrounding circuits are superimposed on signal lines of the electronic components to operate the electronic components. In order to suppress the influence on the electronic component, it is considered that the electromagnetic wave from the electronic component is suppressed. In order to achieve such a so-called electromagnetic wave shield, it has been proposed to form a conductive layer made of an electromagnetic wave shielding material on the inner surface of a box-shaped housing covering an electronic component (see, for example, Patent Document 1).
JP 2001-111282 A

  However, in recent years, there has been a strong demand for downsizing devices using this type of electronic component, as represented by, for example, mobile phones and flat-screen televisions. For this reason, the housing of the electronic component is also required to be downsized. However, if the electromagnetic shielding layer such as the conductive layer is made too thin, a sufficient electromagnetic shielding effect cannot be obtained.

  Accordingly, the present invention is made for the purpose of satisfactorily reducing the size of an electromagnetic wave shielding casing that does not impair the electromagnetic wave shielding effect in an electromagnetic wave shielding case that is configured to be capable of accommodating electronic parts and that can suppress the entry and exit of electromagnetic waves from the electronic parts. It was.

  In order to achieve the above object, the present invention provides a housing body configured to be able to store electronic components, and the housing body provided in at least a part of the inner wall surface of the housing body and housed in the housing body. An electromagnetic wave shielding layer that suppresses electromagnetic waves from entering and exiting an electronic component, and a hole that is formed in the electromagnetic wave shielding layer and that fits a head of a male screw member used in the housing body. It is characterized by that.

  In the present invention configured as described above, an electromagnetic wave that suppresses the electromagnetic waves from entering and exiting from the electronic component housed in the housing body on at least a part of the inner wall surface of the housing body configured to be capable of housing the electronic component. A shield layer is provided. For this reason, the electromagnetic wave entering and exiting the electronic component can be well shielded by the electromagnetic wave shielding layer. Further, the electromagnetic wave shielding layer is provided with a hole portion into which a head portion of a male screw member used in the housing body is fitted. For this reason, even if the electromagnetic wave shielding layer is not so thin, the useless space in the housing body can be reduced and the housing body can be favorably downsized. And since the head part of the external thread member fitted to the said hole part is metal and reflects electromagnetic waves, it can also suppress satisfactorily that electromagnetic waves pass through the part of the hole. Therefore, the electromagnetic wave shielding casing of the present invention can be favorably downsized without impairing the electromagnetic wave shielding effect.

  In addition, although this invention is not limited to the following structures, the said hole part may be drilled ranging from the said electromagnetic wave shield layer to the inner wall face of the said housing body. In this case, the useless space in the housing body can be further reduced by fitting the head portion of the male screw member deeper into the hole. Therefore, in this case, the electromagnetic wave shielding housing can be further downsized.

  The male screw member may be a screw for fixing the electronic component in the housing body. In this case, the useless space in the housing body in the vicinity of the electronic component can be further reduced, and the electromagnetic wave shielding housing can be further downsized.

  Furthermore, the electromagnetic wave shielding layer may be composed of a sheet-like member filled with an electromagnetic wave absorber. In this case, when the electromagnetic wave absorber filled in the sheet-like member absorbs the electromagnetic wave, the electromagnetic wave entering and exiting from the electronic component can be well shielded. Further, since the electromagnetic wave reflected by the head of the male screw member can also be absorbed by the electromagnetic wave absorber, the electromagnetic wave can be shielded better.

  In this case, at least a portion of the housing body on which the electromagnetic wave shielding layer is provided may be formed by cutting a flat synthetic resin plate. When the casing body is molded by injection molding or the like, it is difficult to mold the inner wall surface into a flat shape, and the above-described sheet-shaped electromagnetic wave shielding layer cannot be satisfactorily fixed. On the other hand, when the portion where the electromagnetic wave shielding layer is provided is formed by cutting a flat synthetic resin plate, the flatness of the portion can be ensured satisfactorily. The electromagnetic wave shielding layer can be fixed well without gaps. Therefore, in this case, the durability of the electromagnetic wave shielding casing can be improved and the size can be further reduced.

  Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing the configuration of an electromagnetic wave shielding casing 1 to which the present invention is applied. As shown in FIG. 1, the case main body of the electromagnetic wave shielding case 1 includes a box part 10 configured in a rectangular tray shape and a lid part 20 provided on the box part 10 so as to be opened and closed. ing.

  The box portion 10 includes a rectangular bottom plate 11, and a right side wall 12, a left side wall 13, a rear side wall 14, and a front side wall 15 are erected from the outer periphery of each side of the bottom plate 11. Flange 12 a, 13 a, 14 a, 15 a is erected on the upper end of each side wall 12, 13, 14, 15, and this flange 12 a, 13 a, 14 a, 15 a is formed in a groove 21 having a rectangular cross section formed in the lid portion 20. By fitting, the lid portion 20 is fixed to the box portion 10.

  Further, the bottom plate 11 is provided with columnar female screw members 17 for fixing the lid portion 20 with screws at four corners, and a printed wiring board 90 as an example of an electronic component on which a plurality of CPUs, ICs and the like are mounted is provided in a box portion. Four columnar spacers 18 for supporting inside 10 are provided near the center. Further, the rear side wall 14 is provided with a cord hole 14b for allowing the cord to pass through the inside and outside of the box portion 10.

  On the other hand, a rubber sheet 22 (for example, trade name “MG absorption sheet” manufactured by Kitagawa Industries) filled with ferrite as an example of an electromagnetic wave absorber is attached to the inner wall portion inside the groove 21 of the lid portion 20. A circular hole 23 is formed in a portion of the rubber sheet 22 facing the female screw member 17 over a part of the inner wall of the lid portion 20. In addition, a circular hole 24 is formed in a portion of the rubber sheet 22 facing the spacer 18 over a part of the inner wall of the lid 20. Further, a screw hole 23 a through which a screw (not shown) can be inserted is formed in the center of the hole 23, and a female screw 17 a is cut in the center of the female screw member 17. For this reason, the lid portion 20 is covered by covering the box portion 10 with the lid portion 20, fitting the grooves 21 into the flanges 12 a, 13 a, 14 a, and 15 a, and screwing the screws into the female screw 17 a through the screw holes 23 a. 20 is fixed to the box part 10.

  Next, the lid portion 20 is formed by cutting a flat synthetic resin plate to form an outer shape and a groove 21. After the rubber sheet 22 is attached with an adhesive, the lid portion 20 is further cut to form the hole portion 23. 24 and screw holes 23a.

  The box part 10 is also produced as follows by cutting a flat synthetic resin plate. FIG. 2 is an exploded perspective view showing the configuration of the box portion 10. As shown in FIG. 2, the bottom plate 11 is cut by cutting from a synthetic resin plate integrally with the right side wall 12 and the left side wall 13, and is formed by cutting between the bottom plate 11, the right side wall 12, and the left side wall 13. The fold groove 19 having a V-shaped cross section is bent substantially at a right angle. In the vicinity of the front and rear end edges of the bottom plate 11, the right side wall 12, and the left side wall 13, grooves 11b, 12b, and 13b having a rectangular cross section are formed on the inner wall side. The rear side wall 14 and the front side wall 15 are cut out separately from each other by cutting from a flat synthetic resin plate, and the aforementioned flanges 14a and 15a are formed over the entire circumference. For this reason, after bending the right side wall 12 and the left side wall 13 as described above, the outer frame of the box part 10 is created by fitting the flanges 14a and 15a to the grooves 11b, 12b and 13b and bonding them. .

  Further, circular recesses 11c and 11d are formed in the bottom plate 11 at positions where the female screw member 17 and the spacer 18 are to be fixed, and the female screw member 17 and the spacer 18 are bonded to this portion. The box part 10 is completed. The female screw member 17 and the spacer 18 are both made by injection molding or the like integrally with the metal parts constituting the female screws 17a and 18a.

  Next, FIG. 3 is a cross-sectional view showing a state in which the printed wiring board 90 is fixed on the spacer 18 by screwing a screw 91 as an example of a male screw member to the female screw 18a, and the lid portion 20 is covered. It is. As described above, since the hole 24 is formed in the portion facing the spacer 18 over the inner wall of the lid portion 20, the head of the screw 91 is formed in the hole 24 formed in the rubber sheet 22. They are fitted and lined up with the rubber sheet 22 in the same plane. Since the head of the screw 91 is made of metal, all the electromagnetic waves that have attempted to pass through the hole 24 are reflected by the head of the screw 91. Further, since the rubber sheet 22 is filled with ferrite, the electromagnetic wave that is about to pass through the rubber sheet 22 and the electromagnetic wave reflected on the head of the screw 91 can be satisfactorily absorbed.

  For this reason, in this Embodiment, the electromagnetic waves which are going to enter / exit through the cover part 20 from the printed wiring board 90 can be shielded favorably. Moreover, in this Embodiment, since the head of the screw | thread 91 fits into the hole part 24, even if it does not make the rubber sheet 22 so thin, it can reduce the useless space inside the electromagnetic wave shielding housing | casing 1 favorably. Can do. For this reason, the electromagnetic wave shielding casing 1 can be favorably downsized without impairing the electromagnetic wave shielding effect.

  In addition, this invention is not limited to the said embodiment at all, It can implement with a various form in the range which does not deviate from the summary of this invention. For example, the male screw member is not limited to a screw, and may be a hexagonal nut, for example. Further, instead of the rubber sheet 22 filled with ferrite, various electromagnetic wave shielding layers (for example, trade name “EMI absorption sheet”) such as a resin sheet filled with ferrite, a sheet filled with conductive filler, metal foil, magnetic foil, etc. “Leach Film”, “Cool Provide (registered trademark)”, “Change Gel (registered trademark)”, “Les Miller (registered trademark)”, “Magnefilm”, etc .: all manufactured by Kitagawa Industries Co., Ltd.) can also be used.

  Further, in the above embodiment, the box portion 10 and the lid portion 20 are formed by cutting a flat synthetic resin plate, but these may be formed by injection molding or the like. However, when each part is created as in the above embodiment, it is not necessary to create a mold, and the manufacturing cost can be reduced well. Further, in injection molding, it is difficult to form a portion where the rubber sheet 22 is to be pasted into a flat shape. However, according to the above creation method, the flatness of the portion where the rubber sheet 22 is to be pasted easily. And it can be secured satisfactorily. Therefore, in the said embodiment, the rubber sheet 22 can be favorably fixed to the cover part 20 without a gap, and the durability of the electromagnetic wave shielding housing 1 can be improved and further miniaturized.

It is a perspective view showing the structure of the electromagnetic wave shielding housing | casing to which this invention was applied. It is a disassembled perspective view showing the structure of the box part of the electromagnetic wave shielding housing | casing. It is sectional drawing showing the state which fixed the printed wiring board inside the electromagnetic wave shielding housing | casing.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Electromagnetic shielding housing 10 ... Box part 18 ... Spacer 18a ... Female screw 20 ... Cover part 22 ... Rubber sheet 23, 24 ... Hole part 90 ... Printed wiring board 91 ... Screw

Claims (5)

A housing body configured to store electronic components;
An electromagnetic wave shielding layer that is provided on at least a part of the inner wall surface of the housing body and suppresses electromagnetic waves from entering and exiting the electronic component housed in the housing body;
A hole formed in the electromagnetic wave shielding layer and fitted with a head of a male screw member used in the housing body;
An electromagnetic wave shielding housing comprising:   2. The electromagnetic wave shielding casing according to claim 1, wherein the hole is formed from the electromagnetic shielding layer to an inner wall surface of the casing main body.   3. The electromagnetic wave shielding casing according to claim 1, wherein the male screw member is a screw for fixing the electronic component in the casing main body.   The electromagnetic wave shielding casing according to any one of claims 1 to 3, wherein the electromagnetic wave shielding layer is composed of a sheet-like member filled with an electromagnetic wave absorber.   The electromagnetic shielding casing according to claim 4, wherein at least a portion of the casing main body on which the electromagnetic shielding layer is provided is formed by cutting a flat synthetic resin plate.

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