JP3283161B2 - Shield case and electronic equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shield case suitable for electronic equipment such as a portable radio and a portable receiver such as a portable telephone and a cordless telephone, and an electronic equipment having this shield case.

[0002]

2. Description of the Related Art A schematic configuration of a conventional portable telephone is shown in FIG.
As shown in FIG. 1, the housing of the device is constituted by upper and lower cases 10 and 20 made of plastic, and the circuit board 30 is housed in the upper and lower cases 10 and 20. . In this type of electronic equipment, the circuit board 30
It is necessary to electromagnetically shield the electronic component 31 mounted on the device from the outside of the housing, and a shield structure as shown in FIGS. 16 to 18 has been used.

A conductive layer 21 is formed on the inner wall surface of the lower case 20 by a conductive process such as conductive coating, plating, or vapor deposition.
The conductive layer 21 formed on the periphery of the lower case 20 is brought into contact with the ground pattern 32 of the circuit board 30, or is formed on the rib 22 that partitions the inside of the lower case 20 into a small room for each electric circuit unit. The conductive layer 21 is in contact with the conductive layer 21. In some cases, as shown in FIG. 18, a metal piece 23 having a spring property is attached to an end of the rib 22.
The conductive layer 21 and the ground pattern 32 are electrically connected reliably. On the other hand, the ground pattern 33 is also provided on the back side of the circuit board 30, or a mesh-shaped ground pattern is provided on the inner layer of the circuit board 30. Therefore, the electronic component 31 is covered with the conductive layer 21 provided on the lower case 20 and the ground pattern provided on the circuit board 30, so that the inside and outside can be shielded.

However, as described above, the lower case 20
However, the shield structure in which the conductive treatment is performed has the following problems. First, it is necessary to perform a conductive treatment after the molding of the lower case 20, and therefore, the lower case 2 having the appearance of the device is required.
It is necessary to transport the lower case 20 to the conductive processing step with care so as not to damage the lower case 20 and to perform complicated masking so as not to stain the lower case 20 by the conductive processing. It took a lot of man-hours to finally complete the process, and the cost of the conductive treatment was also high. In addition, as a matter of course, the defective rate of the lower case 20 has been increased due to the presence of the conductive treatment step.

Secondly, in recent years, recycling of plastic products has also become an important issue. However, there is a problem that it is difficult to recycle the lower case 20 which has been subjected to a conductive treatment.

On the other hand, as a shield structure which does not require the lower case 20 to be subjected to a conductive treatment, as shown in FIGS. 19 and 20, a metal case 34 covers the electronic component 31 and the metal case 34 is Although there are some which are joined to the ground pattern 32 of the substrate 30, in this structure, it is very difficult to remove the metal case 34 when repairing an electronic component or the like. Since the metal case 34 is heavy, it is lightweight. However, there is a problem that a dead space is generated between the metal case 34 and the lower case 20, which is not suitable for portable devices such as telephones, which are required to be downsized.

[0007]

As described above, in the shield structure constituted by applying a conductive treatment to a plastic casing, a large number of manufacturing steps are required until the casing is finally completed. In addition, there are problems that the cost is high, the defective rate of the housing is increased due to the presence of the conductive treatment process, and plastic cannot be recycled. Further, in the shield structure using the metal case, there is a problem that the attaching / detaching operation of the metal case is difficult, and the use of the metal case is incompatible with downsizing of the electronic device.

SUMMARY OF THE INVENTION The present invention has been made to solve such a conventional disadvantage, and it is possible to shield electronic components without using a metal case. Therefore, the size and weight of the device can be reduced. It is another object of the present invention to provide a shield structure of an electronic device that can be made and does not need to perform a conductive treatment on a plastic housing itself.

The shield case according to the first aspect of the present invention is provided in a case of an electronic device, wherein the shield case is attached to the circuit board so as to cover an electronic component on the circuit board having a ground pattern. When the case is sandwiched between the inner wall surface of the housing and the circuit board, a plastic sheet is formed so that a tongue piece is provided at a position where the case is brought into contact with the ground pattern of the circuit board. In the sheet, a conductive layer for shielding is formed by performing a conductive process on a position including a portion of the tongue portion in contact with the ground pattern. The electronic device according to the invention according to claim 2 is provided in a housing of the electronic device, has a ground pattern, is mounted on a circuit board on which electronic components are mounted, and is sandwiched between the inner wall surface of the housing and the circuit board. A plastic sheet is formed so that a tongue piece is provided at a position where it can be brought into contact with the ground pattern of the circuit board, and a portion of the formed plastic sheet that contacts the ground pattern in the tongue piece. And a shield case in which a conductive layer for shielding is formed by performing a conductive process on the position including the conductive layer. The shield case according to the invention according to claim 3, wherein the shield case is provided in a housing of an electronic device, and is attached to the circuit board so as to cover an electronic component on the circuit board having a ground pattern. When being sandwiched between the inner wall surface of the housing and the circuit board, a tongue piece is provided at a position where the tongue piece is brought into contact with the ground pattern of the circuit board, and a first engaging portion provided on the housing of the electronic device is provided. A plastic sheet is formed so as to include a second engaging portion to be engaged, and a portion of the formed plastic sheet that contacts the ground pattern in the tongue piece portion and the second engaging portion. A conductive layer is formed by applying a conductive process to a portion of the portion including the portion in contact with the ground pattern. The electronic device according to the invention according to claim 4 is provided in a housing of the electronic device, has a ground pattern, and has a circuit board on which electronic components are mounted, and is sandwiched between an inner wall surface of the housing and the circuit board. A tongue piece is provided at a position where the tongue is brought into contact with the ground pattern of the circuit board, and a first tongue provided on a housing of the electronic device.
A plastic sheet is formed so as to include a second engaging portion that engages with the engaging portion of the tongue piece portion of the formed plastic sheet, the portion being in contact with the ground pattern; And a shield case in which a conductive layer for shielding is formed by performing a conductive process on a position including a portion in contact with the ground pattern in the second engagement portion.

The electronic device according to the invention according to claim 5 is
In a shield case provided on a housing of an electronic device, the shield case is attached to the circuit board so as to cover an electronic component on the circuit board having a ground pattern and an insulated circuit pattern. When sandwiched between the inner wall surface of the housing and the circuit board,
A plastic sheet is formed so as to have a tongue portion at a position where the tongue portion is brought into contact with the ground pattern of the circuit board, and the molded plastic sheet includes a portion of the tongue piece that contacts the ground pattern. A conductive layer for shielding is formed by applying a conductive process to the position, and a conductive layer for a circuit pattern that is insulated from the conductive layer for shielding and is brought into contact with the circuit pattern is formed. . The electronic device according to the invention according to claim 6, wherein the electronic device has a ground pattern and a circuit pattern that is insulated from the ground pattern. When sandwiched between the inner wall surface of the body and the circuit board, a plastic sheet is formed so as to have a tongue piece at a position where it can be brought into contact with the ground pattern of the circuit board, and among the formed plastic sheets, A conductive layer for shielding is formed by applying conductive processing to a position including a portion in contact with the ground pattern in the tongue piece, and the conductive layer for shielding is insulated from the conductive layer for contact with the circuit pattern. And a shield case on which a conductive layer for a circuit pattern is formed.

In the first aspect of the present invention, when the shield case is sandwiched between the inner wall surface of the housing and the circuit board, the tongue portion is provided at a position where the shield case is brought into contact with the ground pattern of the circuit board. Since the shield case is configured by molding a plastic sheet into the shield case, the tongue piece of the shield case is formed from a plastic sheet. Contact is obtained. A second aspect according to claims 3 and 4.
According to the invention, in addition to the above-described configuration, the shield case is further provided with a second engagement portion that engages with the first engagement portion of the housing by molding a plastic sheet. When sandwiched between the substrate and the substrate, the second engaging portion is pressed against the circuit substrate, and the conductive layer is brought into contact with the ground pattern.

In the third aspect of the present invention, the molded plastic sheet is subjected to a conductive treatment so that, in addition to the conductive layer for shielding, a conductive layer for a circuit pattern insulated from the conductive layer is formed. Since it is formed, in addition to the first aspect, a circuit pattern, a lead wire, and a jumper wire that need to be provided on a circuit board can be substituted by the conductive layer for the pattern.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to FIGS. 1 to 8 are views showing a first embodiment, FIG. 1 is a schematic configuration diagram of a mobile phone, FIG. 2 is a cross-sectional view of the mobile phone of FIG. 1, and FIG. 3 is an enlarged view of a circle A in FIG. 4, FIG. 4 is a perspective view of a shield case used in the mobile phone of FIG. 1, FIG. 5 is a cross-sectional view of the shield case of FIG. 4, FIG. 6 is a cross-sectional view of the shield case of FIG. 6, and FIG. 8 is a diagram comparing properties of various plastic sheets.

As shown in FIG. 1, a schematic configuration of a mobile phone according to the present embodiment is formed of upper and lower cases (housings) 110 and 120 made of plastic, and upper and lower cases 110 and 12.
0, and a lower case 110 for covering the electronic components 131 mounted on the circuit board 130.
And a shield case 140 fitted in the concave portion 121 of FIG.

As shown in FIGS. 2 and 4, the shield case 140 is formed of a thin plastic sheet into a shape which can be fitted into the concave portion 121 of the lower case 120 which is divided into a plurality of small rooms by a rib 122 and has a complicated shape. As shown in FIG. 5, the inner wall surface of the molded plastic sheet 141 is subjected to a conductive treatment to provide a conductive layer 142 for shielding.

In this case, in the present embodiment, the thickness of the plastic sheet 141 is 0.15 mm to 0.25 mm, the weight is about 0.6 g, and the plastic sheet 141 is formed of polycarbonate (PC). The thickness of the case 120 (1
mm-2.5 mm) and much thinner and lighter than the weight (about 15 g). Therefore, a complicated case shape can be easily obtained by molding means such as vacuum molding, hot pressing, and in some cases, vacuum injection molding.

As shown in FIG. 8, the material of the plastic sheet 141 is polyester (PET),
PC, polyvinyl chloride (PVC), acrylonitrile butadiene styrene (ABS) and the like can be used, but from the viewpoint of heat resistance and aging (especially curing), it is considered that PC or ABS is good, In particular, PC is used in this example because it is used in food containers and the like and can be manufactured at low cost.

As the conductive treatment for the plastic sheet 141, a conductive coating mixed with a filler of Ni or Cu, electroless plating or electrolytic plating of Ni, Cu, Au, Ag, etc., sputtering, ion plating or the like may be used. Evaporation of the used metal such as Ni, Cu, Au, and Ag can be used. The plastic sheet 14
The thickness of the conductive layer 142 provided on the substrate 1 is about 1 μm to 3 μm.

As shown in FIGS. 6 and 7, the shield case 140 may be provided with conductive layers 142 on both the inner and outer wall surfaces of the plastic sheet 141. In this case, the plastic sheet 141 By providing a large number of small holes 143, the conductive layers 142 provided on the inner wall surface and the outer wall surface of the shield case 140 are electrically connected through the holes 143. As described above, in the shield case 140 in which the conductive layers 142 are provided on both surfaces of the plastic sheet 141, the shielding effect of the electromagnetic wave is as follows: the case where the shield case is formed of a metal plate having the same thickness as the shield case 140. The same shielding effect can be expected.

The above-described shield case 140 is fitted into the concave portion 121 of the lower case 120, and the circuit board 130 is attached to the lower case 120, thereby covering the electronic component 131 as shown in FIGS. It is attached to the circuit board 130. In this case, a tongue piece 145 is provided on the periphery of the shield case 140,
Since this tongue piece 145 is formed of a thin plastic sheet, it has sufficient elasticity. Therefore, since the tongue piece 145 adheres to the ground pattern 132 of the circuit board 130 in a state of elasticity, the conductive layer 142 of the shield case 140 and the ground pattern 132 are securely connected electrically. Further, the recess 1 into which the rib 122 of the lower case 120 of the shield case 140 is inserted.
Since the wall surface 147 of the 46 also contacts the ground pattern 132, the shield case 140 is electrically connected to the ground pattern 132 for each room. On the other hand, the circuit board 130
The ground pattern 133 is also provided on the back side of the.
Therefore, the electronic component 131 includes the conductive layer 142 of the shield case 140 and the ground pattern 133 of the circuit board 130.
, And inside and outside electromagnetic shielding can be performed for each room formed in the shield case 140.

FIGS. 9 and 10 are views showing a second embodiment. FIG. 9 is a perspective view of a shield case, and FIG. 10 shows a change when a tongue portion of the shield case is brought into contact with a circuit board. FIG.

The shield case 140A of the present embodiment has the same configuration as the shield case 140 except that the tongue piece 145A has a curved shape and notches 146 are formed at predetermined intervals. Has become. In this example,
The tongue piece 145 is attached to the ground pattern 132 of the circuit board 130.
When A is pressed, the tongue piece 145A is deformed from the state shown in FIG. 10A to the crushed state as shown in FIG.
Electrical connection between the 45A and the ground pattern 132 can be reliably ensured at many locations. Since the tongue piece 145A has elasticity, it returns to the original state when the pressure is released.

FIGS. 11 and 12 show a third embodiment. FIG. 11 is a perspective view of a shield case, and FIG. 12 shows a change when a tongue portion of the shield case is brought into contact with a circuit board. FIG.

The shield case 140B of this embodiment has the same configuration as the shield case 140 except that spherical protrusions 147 are formed at predetermined intervals on the tongue piece 145B. In this example, when the protrusion 147 of the tongue piece 145B is pressed against the ground pattern 132 of the circuit board 130, the protrusion 147 changes from the state shown in FIG.
Since the shape changes to a collapsed shape as shown in FIG. 3B and closely adheres to the ground pattern 132, electrical connection between the tongue piece 145B and the ground pattern 132 can be reliably secured at many places. Since the projection 147 of the tongue piece 145B has elasticity, it returns to the original state when the pressure is released.

FIGS. 13 and 14 show a fourth embodiment. FIG. 13 is a perspective view of a shield case, and FIG. 14 is a cross-sectional view showing a state where the shield case is mounted on a circuit board. The shield case 140C of this example is common to the shield case 140 in that the shield case 140C is formed into a case shape with a thin plastic sheet 141. However, the masking is performed during the conductive processing, so that the shield conductive layer 142 and the conductive layer 142 are formed. Conductive layer 148 for pattern insulated from layer 142
Is formed. In this example, when the electronic component 131 of the circuit board 130 is covered with the shield case 140C, the pattern conductive layer 148 can be connected to the connection pattern section 136 of the hot line 135 of the circuit board 130. Accordingly, the electronic component can be shielded, and can also serve as a lead wire or a jumper wire.

[0026]

As described above, according to the first aspect of the present invention, when the shield case is sandwiched between the inner wall surface of the housing and the circuit board, the position where the shield case is brought into contact with the ground pattern of the circuit board. Since the shield case is formed by molding a plastic sheet so as to have a tongue portion, since the tongue portion of the shield case is formed from a plastic sheet, by pressing from the housing,
The tongue piece flexes and good electrical contact is obtained. This has the advantage that electrical contact with the ground pattern eliminates the need to provide a separate member from the shield case. According to the second aspect of the present invention, in addition to the above-described configuration, the shield case further includes a second engaging portion that engages with the first engaging portion of the housing. When the shield case is sandwiched between the housing and the circuit board, the second engaging portion is pressed against the circuit board to bring the conductive layer into contact with the ground pattern. It is also possible to prevent radio wave interference between the circuit blocks partitioned by the joint.

In the electronic device according to the third aspect of the present invention, the shield case is insulated from the conductive layer for shielding in addition to the conductive layer for shielding by subjecting the formed plastic sheet to conductive treatment. Since the conductive layer for the patterned pattern is formed, in addition to the effect of the first invention,
There is an effect that a circuit pattern, a lead wire, and a jumper wire that need to be provided on a circuit board can be substituted for the circuit pattern conductive layer of the shield case, and the number of parts of the electronic device can be reduced.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing a schematic configuration of a mobile phone according to a first embodiment of the present invention.

FIG. 2 is a sectional view of the mobile phone according to FIG. 1;

FIG. 3 is an enlarged view of a circle A in FIG. 2;

FIG. 4 is a perspective view of a shield case (one-sided conductive treatment) used for the mobile phone according to FIG. 1;

FIG. 5 is a partial sectional view of the shield case of FIG. 4;

FIG. 6 is a perspective view of a shield case (double-sided conductive treatment) used in the mobile phone according to FIG. 1;

FIG. 7 is a partial sectional view of the shield case of FIG. 6;

FIG. 8 is a diagram comparing the properties of various plastic sheets that can be used for molding the shield case.

FIG. 9 is a perspective view of a shield case according to a second embodiment of the present invention.

FIG. 10 is a view showing the operation when the tongue piece of the shield case in FIG. 9 is brought into contact with the circuit board.

FIG. 11 is a perspective view of a shield case according to a third embodiment of the present invention.

FIG. 12 is a diagram showing an operation when the tongue piece of the shield case of FIG. 11 is brought into contact with the circuit board.

FIG. 13 is a perspective view of a shield case according to a fourth embodiment of the present invention.

FIG. 14 is a sectional view showing a state where the shield case of FIG. 13 is attached to a circuit board.

FIG. 15 is an exploded perspective view showing a configuration of a conventional mobile phone.

FIG. 16 is a sectional view of the mobile phone according to FIG. 15;

FIG. 17 is an enlarged view of a circle B in FIG. 16;

FIG. 18 is a sectional view showing an example in which a metal piece is provided on a rib of a lower case of the mobile phone according to FIG. 15;

FIG. 19 is a cross-sectional view showing the configuration of another conventional mobile phone.

FIG. 20 is an enlarged view of a circle C in FIG. 19;

[Explanation of symbols]

Reference Signs List 120 plastic casing (lower case) 121 recess 130 circuit board 131 electronic component 140, 140A, 140B, 140C shield case 141 plastic sheet 142 shielding conductive layer 148 pattern conductive layer

Continuation of front page (56) References JP-A-4-215500 (JP, A) JP-A-8-30387 (JP, A) JP-A-5-235577 (JP, A) JP-A-8-70195 (JP JP-A-8-222877 (JP, A) JP-A-61-276400 (JP, A) JP-A-61-152445 (JP, A) JP-A-64-57798 (JP, A) 4-18492 (JP, U) Japanese Utility Model 2-20395 (JP, U) Japanese Utility Model 58-133989 (JP, U) Japanese Utility Model 63-90894 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) H05K 9/00

Claims (8)

(57) [Claims] 1. A shield case provided on a housing of an electronic device and attached to the circuit board so as to cover an electronic component on a circuit board having a ground pattern, wherein the shield case is provided on an inner wall surface of the housing. When sandwiched between the circuit boards, a plastic sheet is formed so as to have a tongue piece at a position where it can be brought into contact with the ground pattern of the circuit board. A shield case, wherein a conductive layer for shielding is formed by performing a conductive process on a position including a portion in contact with the ground pattern. 2. A circuit board which is provided in a housing of an electronic device, has a ground pattern, and on which an electronic component is mounted, and a circuit board which is sandwiched between an inner wall surface of the housing and the circuit board. A plastic sheet is formed so that a tongue piece is provided at a position where the tongue piece is brought into contact with the ground pattern. And a shield case in which a conductive layer for shielding is formed by applying the method. 3. A shield case provided on a housing of an electronic device and attached to the circuit board so as to cover an electronic component on the circuit board having a ground pattern, wherein the shield case is provided on an inner wall surface of the housing. A second to engage a first engaging portion provided on a housing of the electronic device, the tongue portion being provided at a position to be brought into contact with an earth pattern of the circuit board when being sandwiched by the circuit board; A plastic sheet is molded so as to have an engaging portion. Of the molded plastic sheet, a portion of the tongue piece that contacts the ground pattern and a ground pattern of the second engaging portion are formed. A shield case wherein a conductive layer for shielding is formed by performing a conductive process on a position including a contacting portion. 4. A circuit board provided in a housing of an electronic device, having a ground pattern, and on which an electronic component is mounted, wherein the circuit board is mounted between an inner wall surface of the housing and the circuit board. A plastic sheet is formed so as to have a tongue piece at a position where it can be brought into contact with the ground pattern, and to have a second engagement portion that engages with a first engagement portion provided on a housing of the electronic device. In the molded plastic sheet, conductive treatment is performed on a position including a portion of the tongue piece that contacts the ground pattern and a portion of the second engagement portion that contacts the ground pattern. And a shield case in which a conductive layer for shielding is formed by the electronic device. 5. A shield case provided on a housing of an electronic device, said shield case being attached to said circuit board so as to cover electronic components on the circuit board having an earth pattern and an insulated circuit pattern. When the shield case is sandwiched between the inner wall surface of the housing and the circuit board, a plastic sheet is formed so as to include a tongue piece at a position where the shield case is brought into contact with an earth pattern of the circuit board. In the plastic sheet thus obtained, a conductive layer for shielding is formed by performing a conductive process on a position including a portion in contact with the ground pattern in the tongue piece, and the conductive layer for shielding is insulated from the conductive layer for shielding. A shield case, wherein a conductive layer for a circuit pattern to be brought into contact with the circuit pattern is formed. 6. A circuit board provided in a housing of an electronic device, having a ground pattern and a circuit pattern insulated from the ground pattern, and a circuit board on which electronic components are mounted; When sandwiched between circuit boards, a plastic sheet is formed so as to have a tongue piece at a position where it can be brought into contact with the earth pattern of the circuit board,
In the molded plastic sheet, a conductive layer for shielding is formed by performing a conductive process on a position including a portion in contact with the ground pattern in the tongue piece, and the conductive layer for shielding is An electronic device comprising: a shield case in which a conductive layer for a circuit pattern that is insulated and brought into contact with the circuit pattern is formed. 7. The shield case according to claim 1, wherein said tongue piece is formed in a curved shape. 8. The electronic apparatus according to claim 2, wherein said tongue piece is formed in a curved shape.