JPH0818266A - Electromagnetic wave shielded circuit unit - Google Patents

Abstract

PURPOSE:To reduce the cost and weight of a circuit unit by forming board holding pieces for holding a circuit board therebetween and sheet inside bent pieces on the bottom of an upper case or top of a lower case and sheet outside bent pieces on the top of the lower case or bottom of the upper case. CONSTITUTION:An electromagnetic wave shielded circuit unit 1 is composed of a circuit board 2 and flattened rectangular shield case 3. A synthetic resin upper and lower cases 4 and 5 are formed as an upper and lower halves of a shield case 3. On a central part of the top of the case 5, two sets of board holding pieces 5a are formed and two vertically up directed sheet inside bent pieces 5b are formed near each piece 5a. On a central part of the bottom of the case 4, board hold pieces 4a are formed at positions corresponding to the pieces 5a and two vertically down directed sheet outside bent pieces 4b are formed near each piece 4a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic wave shielding type in which a circuit board is surrounded by a substantially rectangular parallelepiped conductive shield case so as to prevent electromagnetic waves from leaking to the outside from a circuit unit mounted on an electronic device such as a television game machine. It relates to a circuit unit.

[0002]

2. Description of the Related Art A circuit board is
In an electromagnetic wave shielding type circuit unit surrounded by a flat rectangular parallelepiped conductive shield case, a metal plate is formed by pressing as shown in JP-B-57-3356 and JP-A-3-13793. Since the conductive shield case is constructed by using the conductive shield case, its mechanical strength and rigidity must be dependent on the thickness of the metal plate, and it is difficult to reduce the weight.

Further, in order to hold the circuit board in the approximate center of the space inside the conductive shield case, the work of fixing the circuit board to a holding piece inside the shield case, and a lid for holding the case projecting portion of the circuit board from above and below. It became difficult to reduce the number of parts and work man-hours because it was necessary to fix the to the shield case, and it was not possible to significantly reduce the cost.

[0004]

SUMMARY OF THE INVENTION The present invention relates to an improvement of an electromagnetic wave shielding type circuit unit which overcomes the above-mentioned problems, and a circuit board is surrounded by a substantially rectangular parallelepiped conductive shield case, In an electromagnetic wave shielding type circuit unit for preventing leakage of electromagnetic waves to the outside, an upper case body and a lower case body formed by dividing the outer shape of the rectangular parallelepiped conductive shield case into upper and lower halves, and the upper case. An upper conductive sheet capable of contacting the lower surface of the main body, a lower conductive sheet capable of contacting the upper surface of the lower case body, and held in a substantially vertical center of an internal space formed by the upper case body and the lower case body. And a circuit board that protrudes toward the center of the thickness of the case body on the lower surface of the upper case body and the upper surface of the lower case body. A board holding piece that is sandwiched from above and below is formed, and the inside of the sheet that is located on the outer peripheral side of the board holding piece and projects toward the center of the case body thickness is formed on the lower surface of the upper case body or the upper surface of the lower case body. A bent piece is formed, and a bent piece is formed on the upper surface of the lower case body or the lower surface of the upper case body, and is located on the outer peripheral side by a dimension corresponding to the thickness of the seat inner bent piece with respect to the seat inner bent piece. A sheet outer side bent piece that protrudes toward the center of the thickness of the case body is formed.

Since the present invention is constructed as described above, the case body of the circuit unit need not be made of a metal plate but made of synthetic resin, and the upper conductive sheet and the lower conductive sheet are mechanical strength and rigidity of the case. Therefore, it is possible to reduce the cost by saving the material cost and to reduce the weight.

In the present invention, the circuit board can be electromagnetically sealed by combining the upper and lower case bodies with the upper and lower conductive sheets and integrally connecting the upper and lower case bodies to each other. The number of points and man-hours can be reduced to reduce the cost in this respect.

Further, in the present invention, since the circuit board is sandwiched by the board holding pieces protruding inward from the upper and lower case bodies, the circuit board can be stably and firmly held, and the upper and lower sides of the case body can be held firmly. Since the thickness can be reduced, it is possible to save the cushioning material that suppresses the impact during transportation, reduce the volume, and carry it efficiently,
Moreover, the storage space can be reduced.

By configuring the present invention as in claim 2, the upper and lower conductive sheets can be easily bent and deformed, and the productivity can be greatly improved.

Further, by constructing the present invention as claimed in claim 3 or 4, it is possible to easily perform the bending and deformable processing of the upper and lower conductive sheets.

Further, according to the present invention, the lower conductive sheet, the circuit board, the upper conductive sheet and the upper case body are sequentially stacked on the lower case body, and these are pressed downward. By simply bending the ends of the upper and lower conductive sheets at a right angle, the circuit board can be electromagnetically sealed by the upper and lower conductive sheets, and it is easy to efficiently and efficiently shield the electromagnetic wave shielding circuit unit. Can be produced.

[0011]

EXAMPLES An example of the electromagnetic wave shielding circuit unit 1 of the present invention shown in FIGS. 1 to 6 will be described below. An electromagnetic wave shielding type circuit unit 1 used in a television game machine comprises a circuit board 2 and a flat rectangular parallelepiped shield case 3. The circuit board 2 may be an ordinary printed circuit board or a multilayer circuit board, and has an external connection terminal 2a. It has a main circuit 2b.

An upper case body 4 and a lower case body 5 made of synthetic resin are formed in a shape obtained by dividing the outer shape of the shield case 3 into upper and lower parts, and the lower surface of the upper case body 4 and the upper surface of the lower case body 5 are formed. The upper conductive sheet 6 and the lower conductive sheet 7, which can be respectively contacted with, are made of a thin metal plate. In the upper conductive sheet 6 and the lower conductive sheet 7, the left and right side edges 2c and the back side edge of the circuit board 2 are Local bending parts 6a and 7a as shown in FIG. 2 are formed at the portions corresponding to 2d.

Further, two substrate holding pieces 5a are formed in the substantially central portion of the upper surface of the lower case body 5, and the seat inner side bending portion is located on the left and right outer sides and the inner side of the substrate holding pieces 5a. Two pieces 5b are respectively provided to project upward at a right angle and two board engaging projections 5c are formed on the top ends of the board holding pieces 5a.

Furthermore, a board holding piece 4a is formed at a position corresponding to the board holding piece 5a at a substantially central portion of the lower surface of the upper case body 4, and a sheet inside bent piece of the lower case body 5 is formed. The upper conductive sheet 6 is provided on the outer surface of 5b.
Two sheet outer side bending pieces 4b are provided at right angles and project downward at a position where they can contact each other.

Further, the main circuit 2b of the circuit board 2 is formed with an engagement hole 2e into which the board engagement protrusion 5c of the lower case body 5 can be fitted.

The upper conductive sheet 6 and the lower conductive sheet 7 are provided with fitting holes 6b and 7b, respectively, into which the board holding piece 4a of the upper case body 4 and the board holding piece 5a of the lower case body 5 can be fitted. Has been.

Since the embodiment shown in FIGS. 1 to 7 is constructed as described above, in order to assemble the electromagnetic wave shielding type circuit unit 1, as shown in FIG. The lower conductive sheet 7 is inserted into the sheet inner side bent piece 5 of the lower case body 5 in a state where the dynamic bending portion 7a is positioned inside the sheet inner side bent piece 5b of the lower case body 5.
Placed on b, the left and right side edges 2c, the back side edge 2 of the circuit board 2
The circuit board 2 is placed on the lower conductive sheet 7 so that d is located directly above the locally bent portion 7a of the lower conductive sheet 7, and the circuit board 2 is evenly pressed down over the entire surface. Thus, as shown in FIG. 5, the lower conductive sheet 7 is bordered by the locally bent portion 7a of the lower conductive sheet 7.
The right and left side portions 7c and the rear side portion 7d can be bent upward at a right angle, and can be attached to the inner side surface of the seat inner side bent piece 5b of the lower case body 5, and further, the circuit board 2 The engagement hole 2e can be engaged with the board engagement protrusion 5c of the lower case body 5.

Next, as shown in FIG. 6, with the locally bent portions 6a of the upper conductive sheet 6 positioned outside the tips of the left and right side portions 7c of the lower conductive sheet 7, the upper conductive sheet 6 is formed. 6 is placed on the left and right side portions 7c of the lower conductive sheet 7, and the sheet outer side bent piece 4 of the upper case body 4 is placed.
The lower end of b is the locally bent portion 6a of the upper conductive sheet 6
7 is formed by stacking the upper case body 4 on the upper conductive sheet 6 so that the upper case body 4 is positioned parallel to the lower case body 5. As shown in FIG.
Is closely contacted with the upper surface of the lower case body 5, and the right and left side portions 6c and the rear side portion 6d of the upper conductive sheet 6 are bent downward at right angles, and the outer surface of the sheet inner side bending piece 5b and the sheet outer side bending piece are bent. 4b, and the upper conductive sheet 6 is brought into close contact with the lower surface of the upper case body 4, and the circuit board 2 can be sandwiched between the board holding piece 4a and the board holding piece 5a. The electromagnetic wave shielding circuit unit 1 can be assembled by integrally joining the abutting portions of the upper case body 4 and the lower case body 5 with an adhesive or heat fusion.

As described above, in the embodiment shown in FIGS. 1 to 7, the electromagnetic wave shielding circuit unit 1 can be easily assembled and the productivity can be remarkably improved.

Further, the upper case body 4 and the lower case body 5 are molded by injection molding without fixing means such as screws and bolts and nuts, and the upper conductive sheet 6 and the lower conductive sheet 7 are simply pressed. Since it can be molded, the number of parts can be greatly reduced, the material cost can be reduced, and the cost and weight can be greatly reduced.

Further, the circuit board 2 is sandwiched between the board holding pieces 4a, 5a of the upper case body 4 and the lower case body 5, and the engaging holes 2e are provided in the board engaging protrusions 5 of the lower case body 5.
Since it is engaged with c, no matter what force acts on the electromagnetic wave shielding circuit unit 1, the circuit board 2 is firmly and stably held.

In the electromagnetic wave shielding circuit unit 1 shown in FIGS. 1 to 7, since the front side of the electromagnetic wave shielding circuit unit 1 is open, the electromagnetic wave shielding effect may not be sufficiently exerted. If the electromagnetic wave shielding circuit unit 11 is configured as shown in FIGS. 8 to 9, the front side of the electromagnetic wave shielding circuit unit 11 is an upper conductive sheet.
16, the lower conductive sheet 17 is hermetically sealed by the front side portions 16e, 17e of the lower conductive sheet 17, so that a higher electromagnetic wave shielding effect can be achieved.

The components of the electromagnetic wave shielding type circuit unit 11 shown in FIGS. 8 to 9 are the same as those of the electromagnetic wave shielding type circuit unit 1 shown in FIGS. Is added.

[Brief description of drawings]

FIG. 1 is an overall perspective view showing an embodiment of an electromagnetic wave shielding type circuit unit according to the present invention.

FIG. 2 is an enlarged front view of a portion II of FIG.

FIG. 3 is an exploded perspective view of FIG.

FIG. 4 is a front view showing a first step in assembling an electromagnetic wave shielding circuit unit.

FIG. 5 is a front view showing a second step of assembling the electromagnetic wave shielding circuit unit.

FIG. 6 is a front view showing a third step of assembling the electromagnetic wave shielding circuit unit.

FIG. 7 is a front view showing a fourth step of assembling the electromagnetic wave shielding circuit unit, showing a state where the electromagnetic wave shielding circuit unit is completely assembled.

FIG. 8 is an overall perspective view of another embodiment of the present invention.

9 is an exploded perspective view of the embodiment shown in FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Electromagnetic wave shielding type circuit unit, 2 ... Circuit board, 3 ... Shield case, 4 ... Upper case main body, 5 ... Lower case main body, 6 ... Upper conductive sheet, 7 ... Lower conductive sheet, 11
... electromagnetic wave shielding type circuit unit, 12 ... circuit board, 13 ... shield case, 14 ... upper case body, 15 ... lower case body, 16 ... upper conductive sheet, 17 ... lower conductive sheet.

Claims (5)

[Claims] 1. An electromagnetic wave shielding type circuit unit in which a circuit board is surrounded by a substantially rectangular parallelepiped conductive shield case to prevent leakage of electromagnetic waves from the circuit board to the outside. An upper case main body and a lower case main body formed in a shape divided into two parts, an upper conductive sheet capable of contacting a lower surface of the upper case main body, and a lower conductive sheet capable of contacting an upper surface of the lower case main body. A circuit board which is held substantially vertically in the center of the internal space formed by the upper case body and the lower case body, and the case body has a center thickness in the lower surface of the upper case body and the upper surface of the lower case body. A board holding piece is formed to project toward and clamp the circuit board from above and below. A sheet-inside bent piece that is located on the outer peripheral side of the substrate holding piece and protrudes toward the center of the case body thickness is formed, and the sheet-inside folded piece is formed on the upper surface of the lower case body or the lower surface of the upper case body. An electromagnetic wave characterized in that a sheet outer side bent piece is formed which is located on the outer peripheral side by a dimension corresponding to the thickness of the sheet inner side bent piece with respect to the bent piece and protrudes toward the center of the thickness of the case main body. Shielded circuit unit. 2. The upper conductive sheet and the lower conductive sheet can be easily bent and deformed with each inner edge of the sheet bending piece of the upper case body and the sheet bending piece of the lower case body as a boundary. The electromagnetic wave shielding circuit unit according to claim 1, wherein the circuit unit is treated. 3. The electromagnetic wave shielding circuit unit according to claim 2, wherein the processing is local bending. 4. The electromagnetic wave shielding circuit unit according to claim 2, wherein the processing is perforation processing. 5. The upper and lower protruding dimensions of the seat inner side bent piece and the seat outer side bent piece are substantially the same as the inner diameter (outer) of the case body formed by combining the upper case body and the lower case body. The electromagnetic wave shielding type circuit unit according to claim 1, which is characterized in that.