JPH08130387A - Shield structure of circuit unit - Google Patents

Abstract

PURPOSE: To provide a simplified shield structure of a circuit unit composed of a printed wiring board unit, etc. CONSTITUTION: A shield sheet 15 having a conductive layer 17 formed on the outer face of an insulator 16 is covered with a circuit unit 5, a tool 21 having protrusions 22 is pressed to the outer face of the sheet 15 enough to pass the protrusions through the sheet to contact with a ground pattern 6 of a circuit board which forms the circuit unit, thus conductively connecting the layer 17 to the pattern 6 whereby the unit 5 is shielded by the sheet 15.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shield structure for a circuit unit including a printed wiring board unit and the like.

In recent years, electronic devices, communication devices, etc. have rapidly advanced along with higher performance. On the other hand, there are problems that the electromagnetic waves emitted from the device to the space may affect an external device or may be affected by the electromagnetic waves from another device. Countermeasures against such problems (EMI countermeasures) have become an important issue.

[0003]

2. Description of the Related Art As a measure against EMI of a device, when a device housing is made of a conductive material such as a metal plate, a circuit part (including a power source) which is a source of electromagnetic waves and a circuit board are made of metal The electromagnetic wave is shielded by being housed and covered in the casing.

However, in a device having a complicated appearance and design, the material forming the housing is plastic, and in such a device, the housing is plated with conductive material or coated with a conductive material. Dressing,
Shielding against electromagnetic waves was performed by providing a metal shield plate inside the housing.

Such a typical conventional structure is shown in a perspective view in a separated state in FIG. In FIG. 11, metal plate shields 3 and 4 are provided inside plastic casings 1 and 2, and a circuit unit 5 is sandwiched between the shields 3 and 4.

The shields 3 and 4 are, for example, formed by press-molding a relatively thin structural steel plate into a shallow box-like shape having a brim for mounting around, and the entire surface is rust-proofed by nickel plating or the like. Has been applied.

The circuit unit 5 is composed of a printed wiring board, and ground (earth) patterns 6 of the circuit are formed on both sides of the printed circuit board. The circuit unit 5 is conductively connected to the shields 3 and 4 by tightening with a screw 7, and the shields 3 and 4 are connected. Becomes the same potential as the ground potential of the circuit unit 5 and the circuit unit 5 is electrically covered with the shields 3 and 4, so that electromagnetic waves emitted from the circuit unit 5 to the space are shielded.
At the same time, the intrusion of electromagnetic waves from the outside into the circuit unit 5 is shielded.

[0008]

However, plating or conductive coating for forming a conductive layer for shielding on the conventional plastic casing is expensive and requires secondary processing after plastic molding. Therefore, there is a problem that the cost becomes high.

Providing a shield made of a metal plate inside the housing increases the size and weight of the apparatus and increases the number of parts. This is nothing but an obstacle to downsizing and weight saving in response to the recent demand for downsizing of the device.

In view of the above conventional problems, the present invention provides
It is to provide an effective circuit unit shield structure with a simple structure.

[0011]

According to the gist of the means of the present invention for solving the above problems, the first gist is that a shield sheet having a conductive layer formed on the outer surface of an insulating material is used. A metal fitting having a projection is pressed from the outer surface of the shield sheet while being covered with the circuit unit, and the projection of the metal fitting penetrates the shield sheet and comes into contact with the ground pattern of the circuit board constituting the circuit unit, and through the metal fitting. The shield structure of the circuit unit is configured such that the conductive layer of the shield sheet and the ground pattern of the circuit unit are conductively connected and the circuit unit is shielded by the shield sheet.

According to the second aspect of the invention, a shield sheet having a conductive layer formed on the outer surface of an insulating material is continuously covered on both sides of the circuit unit, and a metal fitting having a protrusion from the outer surface of the shield sheet is provided. When pressed, the protrusion of the metal fitting penetrates the shield sheet and contacts the ground pattern of the circuit board that constitutes the circuit unit, and the conductive layer of the shield sheet and the ground pattern of the circuit unit are conductively connected through the metal fitting. This is a shield structure of a circuit unit in which the unit is shielded by a shield sheet.

According to a third aspect of the present invention, a shield sheet having a conductive layer formed on the outer surface of an insulating material covers the front surface side of the circuit unit and the shield member covers the back surface side of the circuit unit. The metal fitting having a protrusion is attached from the outer surface of the shield sheet, and the protrusion of the metal fitting penetrates the shield sheet and comes into contact with the shield member, and the conductive layer of the shield sheet and the shield member are conductively connected via the metal fitting. A circuit unit has a shield structure in which the circuit unit is shielded by a shield sheet and a shield member.

According to a fourth aspect of the present invention, a circuit board in which a bent conductive layer at an edge of a shield sheet having a conductive layer formed on an outer surface of an insulating material which covers the circuit unit constitutes the circuit unit. Is a shield structure of a circuit unit, which is conductively contacted with the ground pattern of 1. and is shielded by a shield sheet.

A fifth aspect of the invention is that the shield sheet is provided with ventilation holes in the shield structure of the circuit unit according to the above aspects. According to the sixth constitution, the means for attaching the shield sheet to the circuit board and the shield member is a screw in the shield structure of the circuit unit having the constitution.

[0016]

According to the first aspect of the present invention, according to the first aspect of the present invention, the protrusion of the metal fitting is pressed against the shield sheet covering the circuit unit, so that the metal fitting surface or a part of the projection contacts the conductive layer. At the same time, since the protrusion penetrating the shield sheet comes into contact with the ground circuit pattern of the circuit board, the conductive layer of the shield sheet is conductively connected to the ground pattern, and the conductive layer has the same potential as the ground pattern. Shielded by
To be done.

According to the second constitution, since the shield sheet is continuously covered on both sides of the circuit unit, both sides of the circuit unit are shielded by the continuous conductive layers. The ground pattern of the circuit board is conductively connected in the same manner as the means of the first configuration.

According to the third aspect of the invention, the conductive layer of the shield sheet is conductively connected to the shield member by the means for attaching the circuit board to the shield member, and the projection of the metal fitting penetrating the shield sheet by the means for attaching the shield sheet and the shield member. Thus, the conductive layer of the shield sheet and the shield member are conductively connected.

According to the fourth aspect of the invention, by folding back the edge of the shield sheet covering the metal fitting unit, the conductive layer on the outer surface comes into contact with the ground circuit pattern of the circuit board, and the conductive layer of the shield sheet. Is conductively connected to the ground pattern, the conductive layer has the same potential as the ground pattern, and the circuit unit is shielded by the conductive layer.

According to the fifth aspect of the invention, in contrast to the aspects of the above aspects of the invention, ventilation holes are formed in the shield sheet, so that the heat generated on the circuit board is effectively cooled together with the shielding function. obtain.

According to the sixth aspect of the present invention, in addition to the above aspects of the present invention, the shield sheet can be attached and detached by using screws.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The shield structure of a circuit unit according to the present invention will be described in detail below with reference to the accompanying drawings. Note that the same reference numerals are given to the same parts throughout the drawings.

FIG. 1 is a perspective view of a main portion of a first embodiment of the present invention in a separated state. The circuit unit 5 is formed of a printed wiring board and has various circuit components 8 mounted and mounted thereon while forming a circuit pattern for performing a predetermined circuit function. A wiring member 11 for connecting to an external circuit is connected to the connector 9.

A circuit ground pattern 6 made of a conductor foil is formed around the circuit unit 5, and holes 12 for mounting and fixing are provided at important points. The shield sheet 15 of this embodiment has a conductive layer 17 made of metal formed on the outer surface of an insulating material 16 made of plastic such as polyester, and has a bag shape with one end sealed.

The thickness of the insulating material 16 is 0.1 mm (100 μm).
m) is a flexible film or sheet, and the thickness of the conductive layer 17 is about 0.015 mm (15 μm),
For example, aluminum or the like is deposited by vapor deposition, but the material of the insulator 16 and the conductive layer 17 is an example, and the material is not limited to such.

Metal fittings 21 having protrusions are provided at a plurality of holes 12
Are arranged above and below the position corresponding to, respectively. The metal fitting 21 is, for example, as shown in the perspective view of FIG. 2. In FIG. 2A, the protrusions 22 are three conical protrusions integrally formed on one surface.

In FIG. 5B, the protrusions 22 are three protrusions integrally formed in a triangular mountain shape extending in the radial direction and having a higher peripheral side. In FIG. 3C, the protrusions 22 are three protrusions integrally formed in a triangular mountain shape extending in the radial direction and having a higher peripheral side, and a corresponding valley shape on the rear side.

Each of the metal fittings 21 has a circular outer shape, and a through hole 23 for inserting the screw 7 is formed at the center thereof. These metal fittings 21 are, for example, relatively hard steel materials, and are made by press working and are plated with nickel which is excellent in conductivity and rust prevention ability. As other materials, hard copper alloy, stainless steel, etc. can be applied.

The important points inside the plastic casing 1 are
A protrusion (boss) 25 for mounting the circuit unit is integrally formed, and a hole 26 for screwing the screw 7 is provided in each. This hole 26 is the pilot hole of the screw 7, in which case the screw 7 is a self-tapping screw.

In FIG. 1, the metal fittings 2 arranged one above the other
1 is positioned so that the respective protrusions 22 face each other. With the above configuration, the circuit unit 5 is inserted into the bag-shaped inside of the shield sheet 15 through its opening, and the whole circuit unit 5 is covered and accommodated in the shield sheet 15. A side cross-section in this state is shown in FIG. 3 as an enlarged view of a main part.

Although the metal fitting 21 may be selected from any of the embodiments of FIG. 2, the metal fitting 21 illustrated in FIG. 2C is representatively shown in FIG. , Fig. 3
The protrusions 22 are formed at four places.

On the inner surface of the hole 12 formed in the circuit board of the circuit unit 5, a conductive layer (through hole conductor) 28 for connecting the ground patterns 6 formed on both surfaces is formed. Since the position of the hole 12 of the circuit unit 5 can be easily found by pressing it with a finger, the tip of the screw 7 is inserted and inserted through the hole 23 of the metal fitting 21.

By inserting the tip of the screw 7 into the hole 26 of the protrusion 25 of the housing 1 and screwing it in, a screw thread is formed around the inner surface of the hole 26, and the metal fitting 21 is screwed onto the head of the screw 7 and the housing. The circuit board of the circuit unit 5 and the shield sheet 15 are pressed against each other by being pressed against the protrusion 25 of the body 1.

By further tightening the screw 7, as shown in the assembled state of FIG. 4, the tip portion of the protrusion 22 of the metal fitting 21 pushes through the shield sheet 15 and penetrates to contact the ground pattern 6 of the circuit board. Then, cut into the ground pattern 6.

Since the spring washer 29 is inserted and compressed between the head of the screw 7 and the metal fitting 21, the tip of the projection 22 of the metal fitting 21 is kept in contact with the ground pattern 6 by this restoring force. , Shield sheet 15 as shown
The conductive layer 17 and the ground pattern 6 of the circuit unit 5 are electrically connected via the metal fitting 21.

Such a conductive connection is provided by the shield sheet 1.
The conductive layer 17 of No. 5 becomes equal to the ground potential of the circuit unit 5, becomes the ground potential with respect to the entire surface of the circuit unit 5, and is shielded from the outside.

That is, electromagnetic waves from the circuit unit 5 do not leak to the external space, and similar electromagnetic waves from the external space are prevented from entering the circuit unit 5.

FIG. 5 is a perspective view showing a main part of the second embodiment of the present invention in a separated state. The circuit unit 5 is formed of a printed wiring board as in the case of FIG. 1, and various circuit components 8 are mounted and mounted together with the formation of a circuit pattern for performing a predetermined circuit function. A wiring member 11 for connecting to an external circuit is connected to the connector 9.

A circuit grounding pattern 6 made of a conductor foil is formed around the circuit unit 5, and holes 12 for mounting and fixing are provided at important points. The shield sheet 31 of the present embodiment has the same material configuration as the shield sheet 15 of FIG. 1, but is a flat sheet having a shape sufficient to cover the upper surface of the circuit unit 5. The lower surface of the shield sheet 31 in the figure is the insulating material 16, and the upper surface thereof is the conductive layer 17. In this embodiment, the shield sheet 31 has holes 3 at positions corresponding to the holes 12 of the circuit unit 5, respectively.
2 are provided.

The metal fitting 21 arranged on the upper side of the shield sheet 31 can be arbitrarily set and applied from the one shown in FIG. 2, but the projection 22 is directed in the surface direction of the shield sheet 31. The metal fitting 21 has the same configuration and material as those described above.

The important points inside the plastic casing 1 are
A protrusion (boss) 25 for mounting the circuit unit 5 is integrally formed, and a hole 26 for screwing the screw 7 is provided in each. This hole 26 is a pilot hole for the screw 7, in which case the screw 7 is likewise a self-tapping screw.

With the above configuration, the shield sheet 31 is arranged and covered in the state shown in the upper surface of the circuit unit 5. Then, insert the tip of the screw 7 through the hole 23 of the metal fitting 21 into the hole 32 of the shield sheet 31 and the circuit unit 5.
The hole 12 is also inserted and penetrated.

By inserting the tip of the screw 7 into the hole 26 of the protrusion 25 of the housing 1 and screwing it in, a screw thread is formed around the inner surface of the hole 26, and the metal fitting 21 is pressed against the head of the screw 7. The circuit unit 5 with respect to the protrusion 25 of the housing 1.
The circuit board and the shield sheet 31 are brought into pressure contact with each other.

By further tightening the screw 7, the tip portion of the protrusion 22 of the metal fitting 21 pushes through the shield sheet 31 and penetrates into the ground pattern 6 of the circuit board, as described with reference to FIG.

Since a spring washer 29 is inserted between the head of the screw 7 and the metal fitting 21 as in the case of FIG. 4, the tip of the protrusion 22 of the metal fitting 21 is in contact with the ground pattern 6 by this restoring force. Therefore, between the conductive layer 17 of the shield sheet 31 and the ground pattern 6 of the circuit unit 5,
Conductive connection is made via the metal fitting 21.

Such a conductive connection is provided by the shield sheet 3
The conductive layer 17 of No. 1 becomes equal to the ground potential of the circuit unit 5, the entire surface side of the circuit unit 5 becomes the ground potential, and is shielded from the outside world.

That is, electromagnetic waves and the like from the surface of the circuit unit 5 will not leak to the external space, and similar electromagnetic waves and the like in the external space will be prevented from entering the surface side of the circuit unit 5.

In this embodiment, the shield sheet 31 is attached to the front surface side of the circuit unit 5, but
If necessary, it can be selectively applied to mounting on the back side of the circuit unit 5.

In other words, the fact that the shield can be selectively shielded in this way means that the shield sheet 31 is placed in the circuit unit 5.
It is also applicable to both sides of the above, and the use of both sides is substantially the same as the embodiment of FIG. 1, but in this case the shield sheet is not in the shape of a bag, so it is possible to easily comply with any size appropriately. Will be possible.

FIG. 6 is a perspective view showing a main part of the third embodiment of the present invention in a separated state. The circuit unit 5 is composed of a printed wiring board as in the previous embodiment, and various circuit components 8 are mounted and mounted together with the formation of a circuit pattern for performing a predetermined circuit function. A wiring member 11 for connecting to an external circuit is connected to the connector 9.

A circuit ground pattern 6 made of a conductor foil is formed around the circuit unit 5, and holes 12 for mounting and fixing are provided at important points. The shield sheet 35 of the present embodiment has the same material configuration as the shield sheet 15 of the previous embodiment, but the shape is a flat sheet having a size large enough to continuously cover both surfaces of the circuit unit 5. Therefore, it is in the state of being folded back at the intermediate portion in the illustrated state. This shield sheet 35 has an insulating material 16 on the inner side facing
The surface layers on both outer sides are the conductive layers 17.

The metal fittings 21 arranged on both outer sides of the shield sheet 35 can be arbitrarily selected and set from those shown in FIG. 2, but the projections 22 are oriented in the direction of the surface of the shield sheet 35. The metal fitting 21 has the same configuration and material as those described above.

Inside the plastic case 1,
A protrusion (boss) 25 for mounting the circuit unit 5 is integrally formed, and a hole 26 for screwing the screw 7 is provided in each. This hole 26 is the pilot hole of the screw 7, in which case the screw 7 is a self-tapping screw.

With the above configuration, the shield sheet 35 is moved in the direction of the arrow to be arranged on both sides of the circuit unit 5 and covered. Then, insert the tip of the screw 7 through the hole 23 of the metal fitting 21 and push it into the shield sheet 35 to penetrate it.
The hole 12 of the circuit unit 5 and the shield sheet 35 on the back surface side are also penetrated.

The hole 23 of the metal fitting 21 and the housing 1 in the lower part of the drawing
The tip of the screw 7 is inserted into the hole 26 of the protrusion 25 of the screw 25 and screwed in while forming a screw thread around the inner surface of the hole 26, and the metal fitting 21 connects the head of the screw 7 and the surface of the protrusion 25. The circuit board of the circuit unit 5 and the shield sheet 35 are pressed against each other by the space.

By further tightening the screw 7, the tip portion of the protrusion 2 of the metal fitting 21 pushes through the shield sheet 31 and penetrates into the ground pattern 6 of the circuit board, exactly as described with reference to FIG.

A spring washer 29 is inserted between the head of the screw 7 and the metal fitting 21 as in FIG. 4, so that the tip of the protrusion 22 of the metal fitting 21 maintains the contact state with the ground pattern 6 by this restoring force. The conductive layer 17 of the shield sheet 35 and the ground pattern 6 of the circuit unit 5 are conductively connected via the metal fitting 21.

Such a conductive connection is provided by the shield sheet 3
The conductive layer 17 of 5 becomes the same as the ground potential of the circuit unit 5, and the entire surfaces of both sides of the circuit unit 5 become the ground potential and are shielded from the outside.

That is, electromagnetic waves from the circuit unit 5 will not leak to the external space, and similar electromagnetic waves from the external space will be prevented from entering the circuit unit 5.

In this embodiment, both sides of the circuit unit 5 can be shielded. However, since the shield sheet is not in the shape of a bag or a plurality of sheets is used, it is not only easy to handle but also has an arbitrary size. It will be possible to easily respond appropriately.

FIG. 7 is a perspective view showing a main part of a fourth embodiment of the present invention in a separated state. The circuit unit 5 is composed of a printed wiring board as in the previous embodiment, and various circuit components 8 are mounted and mounted together with the formation of a circuit pattern for performing a predetermined circuit function. A wiring member 11 for connecting to an external circuit is connected to the connector 9.

A circuit ground pattern 6 made of a conductor foil is formed around the circuit unit 5, and holes 12 for mounting and fixing are provided at important points. Illustrated circuit unit 5
The shield part 41 arranged below the plate is a rectangular plate made of a conductive material such as a metal plate, and the peripheral flat edge part 42 is provided with inner and outer rows of screw holes 43 and 44. ing. A circuit portion inside the ground pattern 6 of the circuit unit 5 is located in the central recess 45.

Of these, the 43 rows of screw holes on the inner side are aligned so as to match the positions corresponding to the mounting holes 12 of the circuit unit 5. Shield sheet 4 of this embodiment
6 has the same material composition as the shield sheet 15 of the previous embodiment, but is a flat sheet having a shape large enough to cover the shield component 41. Inner and outer rows of holes 47 and 48 are provided at positions corresponding to 44 rows, respectively. In the shield sheet 46, the lower side in the figure is the insulating material 16, and the upper surface side is the conductive layer 17.

The metal fitting 21 arranged on the upper side of the shield sheet 46 can be arbitrarily selected and set from the one shown in FIG. 2, but the projection 22 is directed toward the surface of the shield sheet 46. The metal fitting 21 has the same configuration and material as those described above.

With the above configuration, the shield sheet 46 is covered over the circuit unit 5 and the shield component 41.
Then, the screw 7 is screwed into the screw hole 43 of the shield component 41 through the hole 47 of the shield sheet 46 and the hole 12 of the circuit unit 5 and tightened.

This state is often shown in the right side portion of the enlarged side sectional view of FIG. The shield sheet 46 fastened with the screw 7 and the circuit board of the circuit unit 5 are as follows.

That is, the conductive layer 1 of the shield sheet 46
7 is a flat washer 49 and a spring washer 2 due to the head of the screw 7.
The ground pattern 6 on the lower surface side of the circuit unit 5 is conductively connected to the surface of the edge portion 42 of the shield component 41 in a pressure contact state via a screw 9. Since the screw portion of the screw 7 is screwed into the screw hole 43 of the shield component 41, it is electrically conductively connected to the shield component 41.

As described above, the shield sheet 46
The conductive layer 17 of the circuit unit 5, the ground pattern 6 of the circuit unit 5, and the shield component 41 are all connected to the ground potential of the same potential as the ground circuit of the circuit unit 5 by tightening the screws 7. Is shielded by the shield component 41 and the conductive layer 17 of the shield sheet 46.

Further, the screw 7 is inserted into the hole 23 of the metal fitting 21, and the tip thereof is screwed into the screw hole 44 of the shield component 41 through the hole 48 of the shield sheet 46 and tightened. This state is often shown in the left side portion of the enlarged cross-sectional view of the main part of FIG. The tip portion of the protrusion 22 of the metal fitting 21 fastened with the screw 7 pushes through the shield sheet 46 and penetrates into the surface of the edge portion 42 of the shield component 41.

Since the spring washer 29 is inserted between the head of the screw 7 and the metal fitting 21, the tip of the projection 22 of the metal fitting 21 is kept in contact with the shield component 41 by this restoring force. The conductive layer 17 of the shield sheet 46 and the shield component 41 are conductively connected via the metal fitting 21.

Such conductive connection is provided by the shield sheet 4.
The conductive layer 17 of 6 is the same as the ground potential of the circuit unit 5 and is directly conductively connected to the shield component 41, so that the entire circuit unit 5 is covered and covered.

Therefore, since the circuit unit is doubly shielded, the open end face of the dielectric layer on the end face of the circuit board of the circuit unit 5 is also shielded. In this way, the entire circuit unit 5 is completely shielded, electromagnetic waves from the circuit unit 5 do not leak to the external space, and similar electromagnetic waves from the external space are prevented from entering the circuit unit 5. To be done.

According to the present embodiment, the circuit unit 5 is supported and protected by the shield component 41 which is relatively mechanically strong, so that it is easy to handle. Further, since the metal fitting 21 is not applied to the circuit board of the circuit unit 5, the embodiment of the present invention can be applied to a circuit board made of a ceramic board or the like which is easily damaged.

The shield component 41 described above is not limited to a metal plate but may be a plastic plate or the like having a conductive coating formed thereon, which is sufficiently applicable. FIG. 9 shows a fifth embodiment of the present invention in an enlarged side sectional view of an essential part. In FIG. 1A, the circuit unit 5 has the same structure as that described above, and the circuit board surface has a ground pattern 6 formed of a conductive foil on the periphery thereof.
Is formed, and holes 12 for mounting and fixing are provided at important points. A conductor layer 28 is formed on the inner surface of the hole 12 and electrically connects the ground patterns 6 and 6 on the upper and lower surfaces.

The shield component 51 arranged below the illustrated circuit unit 5 is almost the same as the shield component 41 shown in FIG. 7, and has conductivity such as a metal plate, and the surroundings thereof. It has a flat edge portion 52, and a screw hole 53 for mounting is formed therein so as to correspond to the position of the hole 12 of the circuit unit 5.

The shield sheet 55 of the present embodiment has the same material constitution as the shield sheet 15 of the previous embodiment, and the main surface portion covering the circuit unit 5 is the insulating material 16 on the lower side in the drawing and the conductive layer on the upper surface side. Seventeen.

The periphery of the shield sheet 55 is a bent portion 56 which is folded back downward in the drawing, and therefore the lower surface side of the bent portion 56 in the drawing is the conductive layer 17, and the insulating materials 16 face each other. The width of the bent portion 56 is almost equal to the width of the ground pattern 6 of the circuit unit 5.

A hole 57 is provided in the upper main surface portion of the shield sheet 55 and the bent portion 56 so as to correspond to the hole 12 for mounting the circuit unit 5. With the above configuration, as shown in FIG. 2B, the screw 7 is inserted into the hole 57 of the shield sheet 55, and the screw 12 is also passed through the hole 12 of the circuit unit 5 and screwed into the screw hole 53 of the shield component 51 to be tightened. . This state is illustrated.

Shield sheet 5 fastened with screws 7
5 and the circuit board of the circuit unit 5 are as follows. That is, the conductive layer 17 of the shield sheet 55 is
The screw head is electrically conductively connected to the screw 7 via the flat washer 49 and the spring washer 29, and the conductive layer 17 of the bent portion 56 continuous with the screw was connected to the ground pattern 6 of the circuit unit 7 in a pressure contact state. Has been done.

Ground pattern 6 on the lower surface side of the circuit unit 5
Are conductively connected to the surface of the edge portion 52 of the shield component 51 in a pressure contact state. The screw part of the screw 7 is a shield component 51.
Since it is screwed into the screw hole 53, the shield component 51 is electrically connected.

From the above, the conductive layer 17 of the shield sheet 55, the ground pattern 6 of the circuit unit 5, and the shield component 51 are all set to the same ground potential as the ground circuit of the circuit unit 5 by tightening the screws 7. Now that they are connected, both sides of the circuit unit 5 are shield parts 5.
1 and the conductive layer 17 of the shield sheet 55.

In this way, electromagnetic waves from the circuit unit 5 will not leak to the external space, and similar electromagnetic waves from the external space will be prevented from entering the circuit unit 5.

Also in this embodiment, since the circuit unit 5 is supported and protected by the shield component 51 which is relatively mechanically strong, the handleability becomes good. Further, since the metal fitting 21 is not applied to the circuit board of the circuit unit 5, the embodiment of the present invention can be applied to the metal fitting board made of a ceramic board or the like which is easily damaged.

The above-described shield component 51 is not limited to a metal plate, but a plastic film or the like having a conductive film formed thereon can be sufficiently applied. Shield sheet 5
No. 5 does not leave the bent portion 56 as it is, but by utilizing its property, the main surface and the insulators 16 of the bent portion 56 are fused to each other, so that an easier handling mode can be obtained.

Here, the scope of application of the embodiment of the present invention can be implemented in the following modes. By replacing and applying all the embodiments disclosed in FIGS. 1 to 7 to the shield sheet of the embodiments shown in FIG. 10 which will be described later, a stable shield without using the metal fitting 21 ( That is, the action and effect on the (shielding) function can be obtained.

FIG. 10 is a perspective view showing a main part in a separated state according to a sixth embodiment of a sectional view of the present invention. The circuit unit 5 is composed of a printed wiring board similar to that of FIG. 1, and forms various circuit components 8 together with formation of a circuit pattern for performing a predetermined circuit function.
Has been implemented. A wiring member 11 for connecting to an external circuit is connected to the connector 9.

A ground pattern 6 of a circuit made of a conductor foil is formed around the circuit unit 5, and holes 12 for mounting and fixing are provided at important points. The shield sheet 61 of this embodiment has the same material configuration as the shield sheet 15 of FIG. 1, but is a single flat sheet having a size sufficient to cover the upper surface of the circuit unit 5. In the shield sheet 61, the lower surface in the figure is the insulating material 16 and the upper surface is the conductive layer 17.

In this embodiment, the shield sheet 61 has holes 62 at positions corresponding to the holes 12 of the circuit unit 5.
Is provided. Further, a large number of ventilation holes 63 are formed inside the row of holes 12. The size of the vent hole 63 is appropriately small as will be described later, and is the minimum required for ventilation or slightly larger than that.

The metal fitting 21 arranged on the upper side of the shield sheet 61 can be arbitrarily set and applied from the one shown in FIG. 2, but the projection 22 is directed in the surface direction of the shield sheet 61. The metal fitting 21 has the same configuration and material as those described above.

Protrusions (bosses) 2 for mounting the circuit unit 5 are provided at important points inside the plastic casing 1.
5 is integrally formed, and a hole 2 for screwing in the screw 7
6 are provided for each. This hole 26 is a pilot hole for the screw 7, in which case the screw 7 is likewise a self-tapping screw.

With the above-mentioned structure, the shield sheet 61 is placed on the circuit unit 5 at the position shown in the figure and covered therewith. Then, the tip of the screw 7 is inserted into the hole 62 of the shield sheet 61 and the hole 12 of the circuit unit 5 through the hole 23 of the metal fitting 21.

By inserting the tip of the screw 7 into the hole 26 of the protrusion 25 of the housing 1 and screwing it in, a screw thread is formed around the inner surface of the hole 26, and the metal fitting 21 is pressed against the head of the screw 7. The circuit unit 5 with respect to the protrusion 25 of the housing 1.
The circuit board and the shield sheet 61 are brought into pressure contact with each other.

By further tightening the screw 7, the tip of the projection 22 of the metal fitting 21 and the shield sheet 61 are crushed and pierced through the circuit unit 5 in the same manner as described with reference to FIG.
Bite into the ground pattern 6 on the circuit board.

Since a spring washer 29 is inserted between the head of the screw 7 and the metal fitting 21 as in the case of FIG. 4, the tip of the protrusion 22 of the metal fitting 21 and the ground pattern 6 are also affected by this restoring force.
Since the contact state of is located between the conductive layer 17 of the shield sheet 61 and the ground pattern 6 of the circuit unit 5,
Conductive connection is made via the metal fitting 21.

Such a conductive connection is provided by the shield sheet 6
The conductive layer 17 of No. 1 becomes equal to the ground potential of the circuit unit 5, and the entire front surface side of the circuit unit 5 becomes the ground potential.
It is in a state of being shielded from the outside world.

That is, electromagnetic waves from the surface of the circuit unit 5 are not radiated and leaked to the external space, and similar electromagnetic waves from the external space are prevented from entering the surface side of the circuit unit 5.

According to the embodiment of the present invention, a large number of vent holes 63 are provided.
The heat generated by the operation of the circuit component 8 mounted and mounted on the circuit unit 5 is effectively conducted and dissipated to the external space by the inflow and outflow of air through the ventilation holes 63. By setting the size of the vent hole 63 to be equal to or smaller than the cutoff frequency wavelength of the electromagnetic wave that affects, it is possible not to allow or significantly reduce the passage of harmful electromagnetic wave.

In this embodiment, the shield sheet 61 is attached to the front surface side of the circuit unit 5, but
It can be selectively applied to mounting on the back surface side of the circuit unit 5 as required. When mounting on the back side in this way, the ventilation holes 6 are provided depending on the heat generation state.
The presence / absence of 3 can be set appropriately.

The applicable range of the embodiment of the present invention can be implemented in the following modes. By providing the vent holes 63 in the shield sheets for all the embodiments disclosed in FIGS. 1 to 9, heat can be released and a stable shield can be obtained corresponding to high-density mounting.

As described above, the present invention is not limited to each of the embodiments, and can be applied to the following things, for example, and it is possible to combine such contents. Of course, the present invention also includes combinations of the embodiments.

The means for attaching and pressing each shield sheet in the present invention is not limited to screws, and various known fastening means such as rivets, eyelets, blind rivets, etc. can be applied. Screws are preferred.

The present invention is not limited to mounting on a housing, but can be applied to a shield by a shield sheet. In this case, in addition to the mounting means as described above, in the case of using a screw, a combination with a nut or a nut plate is used. Become.

The nut plate may correspond to each screw or it may be sufficient that a screw hole is formed at a key part of a continuous plate. Such a plate is continuous. Therefore, the workability of tightening the screw or loosening and removing the screw is improved.

The metal fitting is not limited to the one shown in FIG. 2, but it is also possible, for example, to provide a plurality of holes for tightening means in a continuous plate-like main portion and to form a protrusion around each hole. With such a structure, similarly to the nut plate as described above, the tightening operation can be successively and conveniently performed.

Furthermore, the invention is not limited to covering and shielding the entire circuit unit, but it is also possible to appropriately cover and shield the essential parts in terms of parts.

[0106]

As described in detail above, according to the shield structure of the circuit unit of the present invention, a shielded state can be obtained simply and surely, so that the cost is low. Since the inner side is made of an insulating material, it can be brought into close contact with a circuit component or the like, and therefore, the mounting state of the device can be realized by occupying the minimum shield space.

Since the air can flow in and out from the outside with a shortest distance with respect to a place where heat is generated and heat is required to be released, the ventilation efficiency is high. As described above, according to the present invention, since various excellent practical effects are obtained, the present invention can be applied to various types of devices to obtain special actions and effects.

[Brief description of drawings]

FIG. 1 is a perspective view of an essential part of a first embodiment of the present invention.

FIG. 2 is an example of a metal fitting applied to the present invention.

FIG. 3 is an enlarged side sectional view of an essential part in a state in which the shield sheet of FIG. 1 is covered.

FIG. 4 is an enlarged side sectional view of an essential part of FIG. 1 in an assembled state.

FIG. 5 is a perspective view of essential parts of a second embodiment of the present invention.

FIG. 6 is a perspective view of an essential part of a third embodiment of the present invention.

FIG. 7 is a perspective view of an essential part of a fourth embodiment of the present invention.

FIG. 8 is an enlarged side sectional view of an essential part of the assembled state of FIG.

FIG. 9 is an enlarged side cross-sectional view of the essential part of the fifth embodiment of the present invention.

FIG. 10 is a perspective view of essential parts of a sixth embodiment of the present invention.

FIG. 11: Shield structure of conventional circuit unit

[Explanation of symbols]

 1 Case 5 Circuit Unit 6 Ground Pattern 7 Screw 8 Circuit Component 9 Connector 11 Wiring Material 15 Shield Sheet 16 Insulation Material 17 Conductive Layer 21 Metal Fitting 22 Protrusion 23 Hole 25 Protrusion 26 Hole 28 Conductive Layer 29 Spring Washer 31 Shield Sheet 32 Hole 35 Shield sheet 41 Shield component 42 Edge portion 43,44 Screw hole 45 Recess 46 Shield sheet 47, 48 hole 51 Shield component 52 Edge portion 53 Screw hole 55 Shield sheet 56 Bent portion 57 hole 61 Shield sheet 62 hole 63 Vent hole

Claims (6)

[Claims] 1. A shield sheet having a conductive layer formed on an outer surface of an insulating material is covered on a circuit unit, and a metal fitting having a projection is pressed from the outer surface of the shield sheet, and the projection of the metal fitting penetrates through the shield sheet to form a shield sheet. The circuit unit is in contact with the ground pattern of the circuit board, the conductive layer of the shield sheet and the ground pattern of the circuit unit are conductively connected through the metal fittings, and the circuit unit is shielded by the shield sheet. A shield structure for the circuit unit. 2. A shield sheet having a conductive layer formed on the outer surface of an insulating material is continuously covered on both surfaces of a circuit unit, and a metal fitting having a projection is pressed from the outer surface of the shield sheet to shield the projection of the metal fitting. It penetrates through the sheet and contacts the ground pattern of the circuit board that constitutes the circuit unit, and the conductive layer of the shield sheet and the ground pattern of the circuit unit are conductively connected through the metal fittings so that the circuit unit is shielded by the shield sheet. The shield structure of the circuit unit, which is characterized by 3. A shield sheet having a conductive layer formed on the outer surface of an insulating material is covered on the front surface side of the circuit unit, and the circuit unit is attached to a shield member covering the rear surface of the circuit unit from the outer surface of the shield sheet. The metal fitting having the projection is pressed, the projection of the metal fitting penetrates the shield sheet and contacts the shield member, and the conductive layer of the shield sheet and the shield member are conductively connected via the metal fitting, and the circuit unit is shielded by the shield sheet. A shield structure for a circuit unit, which is shielded by a member. 4. A bent conductive layer at the edge of a shield sheet having a conductive layer formed on the outer surface of an insulating material covering the circuit unit is conductively contacted with a ground pattern of a circuit board constituting the circuit unit. A shield structure for a circuit unit, wherein the circuit unit is shielded by a shield sheet. 5. The shield structure for a circuit unit according to claim 1, wherein the shield sheet is formed with ventilation holes. 6. The shield structure for a circuit unit according to claim 1, wherein the means for attaching the shield sheet to the circuit board and the shield member is a screw.