JP7487261B2 - Shield structure - Google Patents

Description

The present invention relates to an electromagnetic wave shielding structure that combines two structures via a shielding member to shield the interiors of both structures from external electromagnetic waves and also shields electromagnetic waves generated inside both structures from the outside, and in particular to a shielding structure that can obtain an appropriate shielding state even if there is a slight error in the outer diameter of the shielding member, and is less susceptible to deterioration of the shielding state due to aging of the shielding member.

The following Patent Document 1 is presented to show an example of a shielding structure invention belonging to the same technical field as the present invention. The shielding structure of this invention has a housing 12, a sealing gasket 14 made of an elastic material whose lower portion is embedded in a predetermined position in the housing 12, a primer layer 18 that covers the upper portion 14a of the sealing gasket 14 and the housing 12, and a metal plating layer 20 deposited on the surface of the primer layer 18. It is believed that this invention can provide an electromagnetic wave shielding housing that is both highly airtight and conductive.

Patent Application No. 2002-198678

Figure 9 is a cross-sectional view showing a schematic diagram of a shielding structure for an electronic device housing previously proposed by the present inventor. As shown in Figure 9(a), this electronic device housing is composed of a box-shaped case 100 and a plate-shaped lid 101. A storage groove 102 is formed in the end face of an opening (not shown) of the case. A shielding member 103 made of a conductive elastic material is placed in the storage groove 102, and the lid 101 is placed on top of it and fixed to the case 100 by a fixing means (not shown), thereby shielding the space inside the case 100 (not shown) from the outside world.

Shield member 103 is a string-like elongated member with a circular cross section, but Fig. 9(a) shows a case where the outer diameter of shield member 103 is larger than the specified dimension due to manufacturing variations, and when pressed into the groove, the cross section is deformed into an ellipse, with a portion protruding outside storage groove 102. When lid body 101 is placed on shield member 103 in the state shown in Fig. 9(a) and fixed to case 100, and shield member 103 is pressed into storage groove 102, as shown in Fig. 9(b), shield member 103 protrudes outside storage groove 102, and the bottom surface of lid body 101 does not abut against the end surface of case 100, creating a gap between lid body 101 and case 100, which may prevent lid body 101 from closing. Furthermore, when the shielding member 103 protrudes from the storage groove 102, the protruding shielding member 103 may become pinched between the lid 101 and the case 100. In that case, even if the necessary shielding performance was obtained in the initial state, the shielding member 103 may be subjected to partial excessive pressure due to being pinched, and may deteriorate over time, resulting in insufficient shielding performance.

Figure 9 (c) shows a case where the outer diameter of the shielding member 103 is smaller than the specified dimension due to manufacturing variations, which is the opposite of the cases shown in Figures 9 (a) and (b). In this case, when the shielding member 103 is pressed into the storage groove 102, the shielding member 103 and the lid body 101 do not come into contact with each other, and the expected shielding may not be obtained.

The present invention has been made to solve the problems in the conventional technology described above, and aims to provide a shield structure that can provide a reliable shielding effect in either case, by ensuring that the shielding member is securely stored in the groove and can properly close the lid even if the dimensions of the shielding member are larger than the specified dimensions, and that can ensure electrical continuity by ensuring that the shielding member is in contact with the lid even if the dimensions of the shielding member are smaller than the specified dimensions, and that can prevent deterioration of the shielding member over time by preventing the shielding member from protruding from the groove.

The shield structure according to claim 1 comprises:
A shielding structure in which a shielding member made of a conductive elastic body is stored in a storage groove provided in a first structure, and a second structure is abutted against the first structure to press the shielding member into the storage groove, thereby shielding the insides of the first structure and the second structure from the outside world,
The storage groove has a shape in which a cut surface intersecting a longitudinal direction of the storage groove has a relative concave portion on both sides of a convex portion on a bottom surface,
The shield member is
When the cartridge is stored in the storage groove, the top portion protrudes out of the storage groove and is not pressed into the recess,
When pressed by the second structure, the entirety of the second structure is pressed into the storage groove, and at least a portion of the second structure is pressed into the recess .

The shield structure according to claim 2 is the shield structure according to claim 1,
The convex portion is characterized in that it has one or more shapes arbitrarily selected from a group of shapes including a rectangular shape, a circular shape, and a triangular shape.

The shield structure according to claim 3 comprises:
A shielding structure in which a shielding member made of a conductive elastic body is stored in a storage groove provided in a first structure, and a second structure is abutted against the first structure to press the shielding member into the storage groove, thereby shielding the insides of the first structure and the second structure from the outside world,
The storage groove has a shape in which a cut surface intersecting a longitudinal direction of the storage groove has a relative concave portion on both sides of a convex portion on a bottom surface,
The shield member is
When the cartridge is stored in the storage groove, the top portion protrudes out of the storage groove and is not pressed into the recess,
When pressed by the second structure, the entire structure is pushed into the storage groove, and is not pushed into the recess, but is in contact with the inner surface of the storage groove excluding the recess and the upper surface of the convex portion .

The shield structure according to claim 4 is the shield structure according to claim 1 or 3,
The shield member is characterized by having a hollow structure.

The shield structure according to claim 5 is the shield structure according to any one of claims 1 to 3 ,
The first structure is a case having a hollow internal space and the storage groove is formed on an end face of an opening that opens up the internal space, and the second structure is a lid provided on the opening of the first structure.

According to the shielding structure described in claim 1, when the shielding member is stored in the storage groove and the first structure and the second structure are assembled, even if the shielding member is larger than the specified dimensions, the shielding member pressed by the second structure is forced into the storage groove and can enter the recesses on both sides of the convex portion, so that it does not protrude outside the storage groove and is securely in close contact with the inner surface of the storage groove and the second structure, thereby obtaining high shielding performance. Also, when the shielding member is stored in the storage groove and the first structure and the second structure are assembled in a shielded state, the shielding member pressed by the second structure has its protruding top pressed into the storage groove and its lower portion entering the recesses on both sides of the convex portion, so that it is securely in close contact with the inner surface of the storage groove and the second structure, thereby providing high shielding performance.

According to the shield structure described in claim 2, the shape of the shield member can be selected according to its elasticity, allowing the state of adhesion of the shield member to the inner surface of the storage groove and the second structure to be appropriately set.

According to the shielding structure described in claim 3, when the shielding member is stored in the storage groove and the first structure and the second structure are assembled, even if the shielding member is larger than the specified dimensions, the shielding member pressed by the second structure is forced into the storage groove and can enter the recesses on both sides of the convex portion, so that it does not protrude outside the storage groove and is securely in close contact with the inner surface of the storage groove and the second structure, thereby obtaining high shielding performance. Also, when the shielding member is stored in the storage groove and the first structure and the second structure are assembled in a shielded state, the protruding top of the shielding member pressed by the second structure is forced into the storage groove, but the other portion does not enter the recess, and is in contact with the inner surface of the groove other than the recess and the upper surface of the convex portion, so that it is securely in close contact with the inner surface of the storage groove and the second structure, thereby obtaining high shielding performance.

According to the shield structure described in claim 4, even if the outer diameter dimension is larger than the specified dimension due to manufacturing errors, the hollow structure allows for a small force to be applied during assembly to press the second structure. In addition, since the structure is flexible, it is easily deformed when pressed by the second structure and easily fits into the storage groove, so it has excellent adhesion to the recesses and protrusions in the storage groove, and can reliably adhere to the inner surface of the storage groove and the second structure, thereby providing high shielding performance.

According to the shielding structure described in claim 5 , by placing electronic devices etc. in the internal space of the case or on the inner surface of the lid, it is possible to install electronic devices etc. in the internal space, and to place the electronic devices etc. in a securely shielded state.

1 is a perspective view of a case having a shield structure according to an embodiment. 1A and 1B are schematic cross-sectional views showing a shield structure of an embodiment using a shield member of a specified dimension, in which FIG. 1A shows the shield structure during assembly, and FIG. 1B shows the shield structure after assembly. 1A and 1B are schematic cross-sectional views showing a shield structure of an embodiment using a shield member smaller than a specified size, in which FIG. 1A shows the shield structure during assembly, and FIG. 1B shows the shield structure after assembly. 1A and 1B are schematic cross-sectional views showing a shield structure of an embodiment using a shield member larger than a specified dimension, in which FIG. 1A shows the shield structure during assembly, and FIG. 1B shows the shield structure after assembly. 1A and 1B are schematic cross-sectional views showing a shield structure of an embodiment using a shield member having a hollow structure, in which FIG. 1A shows the shield structure during assembly, and FIG. 1B shows the shield structure after assembly. 10A and 10B are cross-sectional views showing other shapes of the storage groove in the shield structure of the embodiment. 10A and 10B are cross-sectional views showing other shapes of the storage groove in the shield structure of the embodiment. FIG. 11 is a perspective view showing another example of a case having a shielding structure according to an embodiment of the present invention. 1 is a schematic diagram showing a shielding structure invented by the present inventor prior to the present invention and its problems.

Embodiments of the present invention will be described below with reference to Figures 1 to 8. The components of the embodiments shown in the drawings do not necessarily faithfully represent the same configuration as the actual product, but may be represented diagrammatically to be understood in a manner consistent with the description in the specification, and the dimensional ratios of the components do not necessarily match the actual dimensional ratios.

1 is a perspective view showing an electronic device housing 1 according to an embodiment of the present invention, which is provided with a shielding structure. The electronic device housing 1 (hereinafter also referred to simply as housing 1) includes a box-shaped case 2, which is a first structure, and a plate-shaped lid 3, which is a second structure. The case 2 and the lid 3 are made of metal or a conductive material. A rectangular opening 4 is opened on the upper surface side of the case 2 to expose the internal space S, and a storage groove 6 is formed on the rectangular end surface 5 surrounding the opening 4. The storage groove 6 continues in a rectangular shape along the end surface 5, and the corners are approximately right angles. The outer shape of the lid 3 is a rectangle that matches the outer shape of the end surface 5 of the case 2. The shielding member 7, which will be described later, is pushed into the storage groove 6, the lid 3 is placed on top of it, and the lid 3 is fixed to the case 2 while pressing the shielding member 7 with the lid 3 by a fixing means not shown. As the fixing means, for example, a screw and a screw hole, a clamp-type clamping fixing device, a mechanism for pressing the lid 3 to the case 2, or other known structures, devices, instruments, etc. can be used. This allows the case 2 and the lid 3 to be integrated, shielding the internal space S of the housing 1 from the outside world.

The shielding member 7 is made of a conductive elastic material that has the required hardness and appropriate flexibility and is resistant to gases and moisture that may invade from the outside, for example, an elastic material such as silicone rubber or urethane, to which a conductive substance such as metal particles or powder has been added. The shielding member 7 is a string-like elongated member with a circular cross section and a length at least equal to that of the storage groove 6, and is disposed over the entire length of the storage groove 6.

As mentioned above, the shielding member 7 is a long member with a circular cross section, but as explained in the section "Problems to be Solved by the Invention," its outer diameter may be larger or smaller than the specified dimensions due to manufacturing variations. As a specific example, the outer diameter of the shielding member 7 may include an error of about ±10% of the width of the storage groove 6 due to its material and manufacturing technology. However, even if it deviates from the specified dimensions, it would be convenient if it could be used for a storage groove 6 of the same shape and dimensions and the required shielding performance could be obtained, and the embodiment has exactly such an effect, as explained below.

FIG. 2 shows a shield structure in which a standard shield member 7 having an outer diameter close to a specified value for the dimensions and shape of the storage groove 6 is used.
As shown in Fig. 2(a), the storage groove 6 has a cut surface intersecting its longitudinal direction (perpendicular to the paper surface in Fig. 2) with a rectangular protrusion 8 on the bottom surface, and a corresponding recess 9 on both sides of the rectangular protrusion 8. Such a rectangular protrusion 8 is easily formed by machining such as cutting. When a standard shielding member 7 is pressed into the storage groove 6, the shielding member 7 is deformed and becomes an ellipse whose major axis is the vertical direction in the figure, with a lower part of the shielding member 7 contacting the upper surface of the protrusion 8 and an upper part protruding out of the storage groove 6. In this state, the shielding member 7 does not enter the recess 9 in the storage groove 6.

As shown in FIG. 2(b), when the lid 3 is fixed to the case 2, the shielding member 7 is pressed by the lid 3 and pushed entirely into the storage groove 6, and the lower portion is further deformed and enters evenly into each portion of the two recesses 9, 9. Therefore, due to its shape recovery caused by its elasticity, the deformed shielding member 7 comes into close contact with the back surface (inner surface) of the lid 3, the upper surface of the protrusion 8, the inner surface of the storage groove 6 excluding the recess 9, and part of the inner surface of the recess 9 inside the storage groove 6.

The dividing surface between the lid 3 and the case 2 is therefore sealed by the shielding member 7 placed in close contact with the storage groove 6, achieving a reliable airtight, watertight and electromagnetic wave shielding state.

FIG. 3 shows a shield structure in which an undersized shield member 7S having an outer diameter smaller than a specified value relative to the dimensions and shape of the storage groove 6 is used.
As shown in Fig. 3(a), the storage groove 6 is the same as that shown in Fig. 2. When a shielding member 7S that is in short supply is pushed into this storage groove 6, the shielding member 7S is deformed and becomes an ellipse with the long axis extending vertically in the figure, with a lower part contacting the upper surface of the protrusion 8 and an upper part protruding out of the storage groove 6. The ratio of the short axis to the long axis in the ellipse of the shielding member 7S in Fig. 3(a) is larger than that in Fig. 2(a), and the ellipse of the shielding member 7S in Fig. 3(a) is closer to a circle than that in Fig. 2(a). Therefore, the dimension of the shielding member 7S protruding from the storage groove 6 is smaller than that shown in Fig. 2(a). In this state, the shielding member 7S does not enter the recess 9 in the storage groove 6.

As shown in FIG. 3(b), when the lid 3 is fixed to the case 2, the shielding member 7S is pressed by the lid 3 and deformed, and is pushed entirely into the interior of the storage groove 6, but does not deform to the point of entering the two recesses 9, 9. Therefore, due to its shape recovery caused by its elasticity, the deformed shielding member 7S comes into close contact with the back surface (inner surface) of the lid 3, part of the inner surface of the storage groove 6 excluding the recess 9, and the upper surface of the protrusion 8 inside the storage groove 6.

The dividing surface between the lid 3 and the case 2 is therefore sealed by the shielding member 7S placed in close contact with the storage groove 6, and although the area of the contact surface is somewhat smaller than when a standard shielding member 7 is used, the necessary airtightness, watertightness and electromagnetic wave shielding are achieved without any problems.

FIG. 4 shows a shield structure in which an oversized shield member 7L having an outer diameter larger than a specified value relative to the dimensions and shape of the accommodation groove 6 is used.
As shown in Fig. 4(a), the storage groove 6 is the same as that shown in Fig. 2. When an oversized shielding member 7L is pushed into this storage groove 6, the shielding member 7L is deformed and becomes an ellipse with the long axis extending vertically in the figure, with a lower part contacting the upper surface of the protrusion 8 and an upper part protruding out of the storage groove 6. The ratio of the short axis to the long axis of the ellipse of the shielding member 7L in Fig. 4(a) is smaller than that in Fig. 2(a), and the ellipse of the shielding member 7L in Fig. 4(a) is more elongated than that in Fig. 2(a). Therefore, the dimension of the shielding member 7L protruding from the storage groove 6 is larger than that shown in Fig. 2(a). In this state, the shielding member 7L does not enter the recess 9 in the storage groove 6.

As shown in FIG. 4(b), when the lid 3 is fixed to the case 2, the shielding member 7L is pressed by the lid 3 and pushed entirely into the storage groove 6, and a lower portion of the shielding member 7L is further deformed and enters evenly into the two recesses 9, 9, substantially filling the two recesses 9, 9. Therefore, due to its elastic shape recovery, the deformed shielding member 7L comes into close contact with the back surface (inner surface) of the lid 3, almost the entire inner surface of the storage groove 6 including the recesses 9, and the upper surface of the protrusion 8 inside the storage groove 6.

The dividing surface between the lid 3 and the case 2 is therefore sealed with the shielding member 7L placed in close contact with the storage groove 6, achieving airtightness, watertightness and electromagnetic wave shielding that is equal to or better than that achieved when the standard sealing material 7 is used.

FIG. 5 shows a shielding structure in which a hollow shielding member 7H is used, the outer diameter of which is larger than a prescribed value relative to the dimensions and shape of the storage groove 6 and which has a circular cavity H therein.
As shown in Fig. 5(a), the storage groove 6 is the same as that shown in Fig. 2. When a hollow shielding member 7H is pressed into this storage groove 6, the shielding member 7H is deformed and assumes an elliptical shape with the long axis extending vertically in the figure, with a lower part in contact with the upper surface of the protrusion 8 and an upper part protruding out of the groove. The dimension by which the shielding member 7H protrudes from the storage groove 6 is the same as that shown in Fig. 4(a). In this state, the shielding member 7H does not enter the recess 9 in the storage groove 6.

As shown in FIG. 5(b), when the lid 3 is fixed to the case 2, the shield member 7H is pressed by the lid 3 and pushed entirely into the storage groove 6, and the lower portion is further deformed and enters evenly into each portion of the two recesses 9, 9. The circular hollow portion H of the shield member 7H is crushed into an irregular shape or a roughly star shape as shown. Therefore, due to its shape recovery caused by its elasticity, the deformed shield member 7H comes into close contact with the back surface (inner surface) of the lid 3, the upper surface of the protrusion 8, the inner surface of the storage groove 6 excluding the recess 9, and part of the inner surface of the recess 9 inside the storage groove 6.

The dividing surface between the lid 3 and the case 2 is therefore sealed by the shielding member 7H placed in close contact with the storage groove 6, achieving an airtight condition, watertight condition and electromagnetic wave shielding condition similar to or even more reliable than when the standard shielding member 7 is used.

The hollow shielding member 7H shown in FIG. 5 is easily crushed when pressed into the housing 7 by the lid 3 because it is hollow, and is easily contained within the storage groove 6 and is not likely to protrude from the storage groove 6. In addition, because it is easily crushed, only a small force is required to press the lid 3 into the case 2 when attaching the lid 3 to the case 2, making it easy to assemble the housing 1.

Figure 6 shows another example of the shape of the protrusion 8 provided in the storage groove 6. The protrusion 8R has a semicircular cross-sectional shape in a cross section perpendicular to the longitudinal direction. When the shielding member 7 pressed into the storage groove 6 hits the semicircular protrusion 8R, the load on the shielding member 7 is distributed and made uniform compared to when it hits the rectangular protrusion 8, so the shielding member 7 is less likely to be damaged, and the lower part of the deformed shielding member 7 is more likely to enter the recess 9, making it easier for the shielding member 7 to adhere more closely to the inner surface of the storage groove 6. In addition, when using a shielding member 7 made of a material that is harder and less likely to deform, it is preferable to use a semicircular protrusion 8R rather than a rectangular protrusion 8, because the shielding member 7 is more likely to deform and enter the recess 9.

Figure 7 shows another example of the shape of the protrusion 8 provided in the storage groove 6. This protrusion 8T has a triangular cross-sectional shape in a cross section perpendicular to the longitudinal direction. When the shielding member 7 pressed into the storage groove 6 hits the triangular protrusion 8T, the lower part of the deformed shielding member 7 is more likely to enter the recess 9 than when it hits a rectangular protrusion 8, and the shielding member 7 is more likely to adhere to the inner surface of the storage groove 6. In addition, when using a shielding member 7 made of a material that is harder and less likely to deform, it is preferable to use a triangular protrusion 8T rather than a rectangular protrusion 8, because the shielding member 7 is more likely to deform and enter the recess 9.

Although not shown, the cross-sectional shape of the convex portion in a cross section perpendicular to the longitudinal direction of the storage groove 6 may be a trapezoid with a short upper base and a long lower base, in addition to the examples shown in Figures 2 to 5, 6 and 7. In this case as well, compared to a rectangular convex portion 8, the lower portion of the deformed shielding member 7 is more likely to enter the recessed portion 9, and the shielding member 7 is more likely to adhere to the inner surface of the storage groove 6. Furthermore, when using a shielding member 7 made of a material that is harder and less likely to deform, it is preferable to use a trapezoidal convex portion rather than a rectangular convex portion 8, as this makes it easier for the shielding member 7 to deform and enter the recessed portion 9.

The semicircular convex portion 8R in FIG. 6, the triangular convex portion 8T in FIG. 7, and the trapezoidal convex portion described above are preferably formed at the same time as the case 2 made of metal or conductive material is manufactured using a mold, since this reduces manufacturing costs compared to forming them by machining such as cutting. However, the rectangular convex portion 8 may be formed by a mechanical process, such as cutting, after the case 2 is manufactured.

Figure 8 is a perspective view showing another structural example of the electronic device housing 1a of the embodiment. This housing 1 differs from the housing 1 of the structural example of Figure 1 in that the rectangular storage groove 6 provided on the end surface 5 of the opening 4 of the case 2a is bent at its corners by drawing a curve of approximately 90 degrees at the center angle. With this structure, when attaching the cover 3 to the case 2a, the shielding member 7 is easily bent along the corners of the storage groove 6, making it easier to push it into the storage groove 6. The ease with which the shielding member 7 bends depends on its material, but if the shielding member 7 is relatively flexible, the storage groove 6 with right-angled corners shown in Figure 1 may be used, but if the shielding member 7 is relatively less flexible, the storage groove 6 with rounded corners shown in Figure 8 is preferable.

Although not shown in Figs. 1 and 8, these housings 1, 1a house electronic devices or electronic circuits that generate electromagnetic waves, or electronic devices or electronic circuits that should not be affected by external electromagnetic waves. These electronic devices may be provided on the bottom surface of the case 2, 2a and placed in the internal space S, or may be provided on the back surface of the lid 3 and placed in the internal space S of the case 2, 2a. As an example of a structure in which electronic devices are provided on the back surface of the lid 3, a circuit board on which an electronic circuit is mounted may be used as the lid 3, and the electronic circuit may be attached to the opening of the case 2 with the electronic circuit facing downwards.

In addition, the housing 1 in the embodiment is composed of the case 2, 2a and the cover 3, but two cases 2, 2 or 2a, 2a having the same shape of the opening 4 and the end face 5 surrounding the opening 4 may be combined so that the openings 4, 4 correspond to each other to form one housing 1. In that case, the two cases 2, 2 or 2a, 2a may be combined with a circuit board in between.

The shielding structure of the housings 1 and 1a in the above-described embodiment can effectively shield electromagnetic waves as described above, but because the elastic shielding members 7, 7L, 7S, and 7H are structured to fit closely to the inner surface of the storage groove 6, they also have sufficient sealing properties against moisture and gas, and the term "shield" in this invention means watertightness and airtightness in addition to shielding electromagnetic waves.

1, 1a... Electronic device housing (housing)
2, 2a... Case as a first structure 3... Cover as a second structure 6... Storage groove 7, 7L, 7S, 7H... Shielding member 8, 8R, 8T... Convex portion 9... Concave portion

Claims (5)

A shielding structure in which a shielding member made of a conductive elastic body is stored in a storage groove provided in a first structure, and a second structure is abutted against the first structure to press the shielding member into the storage groove, thereby shielding the insides of the first structure and the second structure from the outside world,
The storage groove has a shape in which a cut surface intersecting a longitudinal direction of the storage groove has a relative concave portion on both sides of a convex portion on a bottom surface,
The shield member is
When the cartridge is stored in the storage groove, the top portion protrudes out of the storage groove and is not pressed into the recess,
A shield structure, characterized in that when pressed by the second structure, the entirety of the shield is pressed into the storage groove and at least a portion of the shield is pressed into the recess . The shield structure according to claim 1, characterized in that the convex portion has one or more shapes arbitrarily selected from a group of shapes including a rectangular shape, a circular shape, and a triangular shape. A shielding structure in which a shielding member made of a conductive elastic body is stored in a storage groove provided in a first structure, and a second structure is abutted against the first structure to press the shielding member into the storage groove, thereby shielding the insides of the first structure and the second structure from the outside world,
The storage groove has a shape in which a cut surface intersecting a longitudinal direction of the storage groove has a relative concave portion on both sides of a convex portion on a bottom surface,
The shield member is
When the cartridge is stored in the storage groove, the top portion protrudes out of the storage groove and is not pressed into the recess,
A shielding structure characterized in that, when pressed by the second structure, the entire structure is pushed into the interior of the storage groove and is in contact with the inner surface of the storage groove excluding the recess and the upper surface of the convex portion without being pushed into the recess . 4. The shield structure according to claim 1, wherein the shield member has a hollow structure . 4. The shielding structure according to claim 1, wherein the first structure is a case having a hollow internal space and the storage groove is formed on an end face of an opening that opens the internal space, and the second structure is a cover provided on the opening of the first structure.

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