JP2005158931A - Shielding structure of printed circuit board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide the shielding structure of a printed circuit board which can obtain an excellent shielding effect by a simple structure. <P>SOLUTION: In the shielding structure of a printed circuit board, a plurality of printed circuit boards, in each of which a conductive layer 25 is formed on the front surface side of a base material 21 and a copper foil circuit 23 is provided on the rear surface, are stacked in the thickness direction thereof. In this structure, the printed circuit boards 3, 5 are stacked in a state that the conductive layers 25, 25 of the respective printed circuit boards 3, 5 are arranged on the same surface side, and the conductive layers 25, 25 of the respective printed circuit boards 3, 5 are grounded. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a shielding structure for a printed circuit board.

  Various electronic devices such as lamps and motors are mounted on automobiles and the like. In order to supply current from a power source such as a battery or control signals from a control device to the electronic devices, FIG. As shown in FIG. 2, a wire harness 103 composed of a plurality of general electric wires or shielded electric wires 101 is connected. A connector 105 is provided at the end of the wire harness 103.

FIG. 11 is a perspective view showing an end portion of the shielded electric wire 101. This shielded electric wire 101 is composed of a coating layer 107, an electromagnetic shielding layer 109, and two core wires 111, 111 from the outside. The electromagnetic shielding layer 109 is a grounded (grounded) high-conductivity conductor. The core wire 111 is protected from induction by static coupling, that is, static noise (see, for example, Patent Document 1).
JP-A-8-293692

  However, in the prior art, it is necessary to arrange a large number of shielded electric wires 101 to be connected to each electronic device, and the joint processing or the like at the connecting portion for connecting the end of the shielded electric wire 101 to the conduction circuit may be complicated. was there.

  Accordingly, an object of the present invention is to provide a shielding structure for a printed circuit board that can obtain an excellent shielding effect with a simple structure.

  In order to achieve the above object, the invention described in claim 1 is a printed circuit board in which a conductive layer is provided on the surface side of a base material and a plurality of printed circuit boards provided with circuits on the back side are laminated in the thickness direction. The printed circuit board is laminated in a state where the conductive layer of at least one printed circuit board is arranged on the surface side, and the conductive layer of each printed circuit board is grounded.

  According to a second aspect of the present invention, there is provided the printed circuit board shielding structure according to the first aspect, wherein a grounding body is provided on a side of the circuit on the back surface side of the printed circuit board.

  The invention described in claim 3 is the printed circuit board shielding structure according to claim 1 or 2, wherein the conductive layer is a copper foil, and the circuit is etched copper along a pattern. It consists of foil.

  Furthermore, the invention described in claim 4 is the printed circuit board shielding structure according to claim 2, wherein the grounding body is a shield circuit made of copper foil.

  The invention described in claim 5 is the printed circuit board shielding structure according to any one of claims 1 to 4, wherein a connection connector is provided at one end of the side edge of the printed circuit board, When the printed circuit boards are stacked, the orientations of the printed circuit boards are alternately arranged so that the connection connectors do not overlap.

  According to the printed circuit board shielding structure described in claim 1, since the plurality of printed circuit boards are stacked in the thickness direction, the circuit formed on the back side of the predetermined printed circuit board Since it is shielded by the conductive layer formed on the surface side and the conductive layer on the surface side of the adjacent printed circuit board, it is possible to shield the circuit on the printed circuit board with a very simple structure.

  According to the shielding structure of the printed circuit board described in claim 2, since the grounding body is provided on the side of the circuit on the back surface side of the printed circuit board, the circuit is also shielded from noise entering from the side. be able to. Therefore, the circuit formed on the back side of the printed board can be efficiently shielded not only from the front side and the back side of the printed board but also from the side of the circuit.

  According to the printed circuit board shielding structure described in claim 3, the conductive layer is a copper foil, and the circuit is formed of an etched copper foil, and is formed of a copper foil that is highly conductive and inexpensive. Therefore, it is possible to obtain a printed circuit board shielding structure with high shielding efficiency at low cost.

  According to the shielding structure of the printed circuit board described in claim 4, since the grounding body is made of copper foil formed on the back side of the base material, the shielding structure from the side of the circuit is also shielded at a low cost. Efficiency can be increased.

  According to the printed circuit board shielding structure described in claim 5, the printed circuit boards are stacked while alternately arranging the directions of the printed circuit boards so that the connectors do not overlap with each other. Can be laminated. Therefore, the shielding efficiency of the circuit can be improved.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[First embodiment]
1 is a perspective view showing a harness module 1 according to a first embodiment of the present invention, FIG. 2 is a cross-sectional view taken along the line AA of FIG. 1, and FIG. 3 is an exploded perspective view of the harness module 1 of FIG.

  As shown in these drawings, the harness module 1 according to the first embodiment is composed of two printed boards 3 and 5 stacked one above the other, and the first printed board 3 is on the upper side (front side) of these. The second printed circuit board 5 is disposed on the lower side (back side).

  As shown in FIG. 2, a conductive layer 25 made of a copper foil attached to the surface side of the base material 21 is formed on one surface on the surface side of the first printed circuit board 3 and the second printed circuit board 5. .

  Further, as shown in FIGS. 2 and 3, three protruding portions 7 are formed on the side edge of the first printed circuit board 3, and two connecting connectors 11 are provided in the protruding portion 7. They are fixed in close contact with each other. The connection connector 11 is formed in a box shape having a substantially U-shaped cross section from the upper surface, the lower surface, the side surface, and the front surface. In addition, connector terminals 17 and 19 that penetrate the front surface 15 from the inside of the connection connector 11 are provided vertically. As shown in FIG. 2, the upper-side connector terminal 17 is bent in a substantially L shape when viewed from the side, one end 17 a is disposed inside the connector 11 for connection, and the other end 17 b is a plate for the substrate 21. It penetrates in the thickness direction and is connected to the conductive layer 25 on the surface of the base material 21 and the copper foil circuit 23 on the back surface of the base material 21. The conductive layer 25 is formed from a copper foil, and the copper foil circuit is formed from an etched copper foil. A plurality of the upper connector terminals 17 are arranged along the longitudinal direction of the base member 21, but only the rightmost upper connector terminal 17 in FIG. The other upper connector terminal 17 is connected to the conductive layer 25, and is supported by a portion of the general surface 27 other than the conductive layer 25 in the protruding portion 7. It is not always necessary that one or more connector terminals of each connector be grounded to the conductive layer 25, and it is sufficient that at least one connector terminal is grounded to the conductive layer 25 on the same substrate.

  Further, the lower connector terminal 19 is also bent in a substantially L shape when viewed from the side, one end 19 a is disposed inward of the connector 15 for connection, and the other end 19 b penetrates the base material 21 and the back surface of the base material 21. It is connected to the copper foil circuit 23 on the side.

  The second printed circuit board 5 is also configured in substantially the same structure as the first printed circuit board 3. That is, the base material 21 itself is formed with a conductive layer 25 made of copper foil on the front surface side and the copper foil circuit 23 made of etched copper foil on the back surface side, like the first printed circuit board 3. Is formed. However, it differs from the first printed circuit board 3 in that only one connection connector 13 is arranged on each protrusion 9.

  FIG. 4 is a bottom view of the harness module 1 of FIG. 1 viewed from below.

  A copper foil circuit 23 is formed on the back surface side of the second printed circuit board 5, and the upper side connector terminal 17 and the lower side connector terminal 19 are provided at the ends of the circuit pattern constituting the copper foil circuit 23. The other end portions 17b and 19b are connected.

  The first embodiment has the following operational effects.

  As shown in FIG. 2, the copper foil circuit 23 formed on the back surface side of the first printed circuit board 3 includes a conductive layer 25 formed on the front surface side of the first printed circuit board 3 and a second printed circuit board. 5 is protected from above and below by a conductive layer 25 formed on the front surface side of 5. Since these conductive layers 25 and 25 are formed on one surface widely on the surface side of each printed circuit board 3 and 5 and are grounded, they serve as shield surfaces that shield and protect the copper foil circuit 23. .

  Therefore, it is possible to efficiently protect the copper foil circuit 23 formed on the back surface side of the first printed circuit board 3 from static noise caused by various electrical components, drive components, and the like.

  Moreover, since the conductive layer 25 is a copper foil attached to the entire surface of the base material 21, the shield surface can be easily and inexpensively manufactured.

  In the first embodiment, the two printed boards 3 and 5 have been described. However, the present invention is not limited to this, and three or more printed boards are arranged in the plate thickness direction. You may laminate | stack sequentially.

[Second Embodiment]
Next, a second embodiment of the present invention will be described, but portions having the same structure as that of the first embodiment will be described using the same reference numerals.

  FIG. 5 is a bottom view of the printed circuit board 31 according to the second embodiment of the present invention, and FIG. 6 is an enlarged bottom view of a portion B in FIG.

  A copper foil circuit 23 obtained by etching the copper foil according to the circuit pattern is formed on the bottom surface of the printed board 31. A plurality of shield circuits 33 are formed on the side of the copper foil circuit 23 so as to surround the copper foil circuit 23. The shield circuit 33 is formed in the vertical and horizontal directions along the circuit pattern of the copper foil circuit 23, so that the copper foil circuit 23 is disposed so as to be surrounded by the shield circuit 33. The shield circuit 33 is formed wider than the circuit pattern of the copper foil circuit 23. The shield circuit 33 can be combined by appropriately adding a pattern of the shield circuit 33 extending in the vertical and horizontal directions, and the branch of the shield circuit 33 can be appropriately taken out from the circuit pattern of the shield circuit 33 by jumper printing. it can.

  Next, the cross-sectional structure of the printed circuit board when jumper printing is performed will be briefly described with reference to FIGS. 7 is a cross-sectional view of a printed circuit board in which copper foil circuits are connected to each other via a jumper. FIG. 8 is a bottom view of the printed circuit board of FIG. 7. Both FIGS. A sectional view of the formed state is shown.

  A copper foil circuit 23 made of a copper foil is formed on the surface side of the insulating base material 21, and a resist 35 is formed on the surfaces of the copper foil circuit 23 and the base material 21. A first undercoat 37 and a second undercoat 39 are sequentially laminated on the surface of the resist 35. The resist 35, the first undercoat 37 and the second undercoat 39 all have insulating properties. doing. Further, among the three copper foil circuits 23 in FIG. 7, the upper surfaces of the left and right copper foil circuits 23, 23 are connected by a copper paste jumper 41, and a transparent overcoat 43 is formed on the outermost surface side. ing. Since the overcoat 43 is transparent, it is not shown in FIG. The copper paste jumper 41 is a conduction path for connecting the left and right copper foil circuits 23, and the overcoat is provided for the purpose of protecting the copper paste jumper 41 from the outside and preventing insulation and corrosion. Yes.

  According to the second embodiment, since the circuit formed on the back surface side of the base material 21 is shielded not only from the front surface side and the back surface side but also from the side, the shielding efficiency is further improved.

  The present invention is not limited to the above-described embodiments, and various modifications and changes can be made based on the technical idea of the present invention.

  For example, in the first embodiment, the upper connector terminal 17 is connected to the conductive layer 25 on the surface of the base material 21, but as shown in FIG. 9, a part of the conductive layer 125 faces the connector for connection 111. If the harness module 101 is configured such that the upper connector terminal 117 is connected to the extended portion 125a, the upper connector terminal 117 and the lower connector terminal 119 provided in the connector 111 are the same length. Can be unified.

  In addition, as described with reference to FIG. 2, the upper and lower portions of the copper foil circuit 23 are sandwiched between the conductive layers 25, 25, but a similar shielding effect can be obtained by arranging an earth circuit in place of these conductive layers 25. Can be obtained.

It is a perspective view which shows the harness module by 1st Embodiment of this invention. It is sectional drawing by the AA line of FIG. It is a disassembled perspective view of the harness module of FIG. It is the bottom view which looked at the harness module of Drawing 1 from the lower part. It is a bottom view of the printed circuit board by 2nd Embodiment of this invention. It is the bottom view to which the B section of Drawing 5 was expanded. It is sectional drawing of the printed circuit board which connected copper foil circuits through the jumper. It is a top view of the printed circuit board of FIG. It is a perspective view which shows the harness module by the modification of this invention. It is a perspective view which shows the conventional wire harness. It is an enlarged side view which shows the edge part of the shield electric wire which comprises the wire harness of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Harness module 3 ... 1st printed circuit board (printed circuit board)
5 ... Second printed circuit board (printed circuit board)
DESCRIPTION OF SYMBOLS 11, 13 ... Connector for connection 21 ... Base material 23 ... Copper foil circuit (circuit)
25 ... Conductive layer 31 ... Printed circuit board 33 ... Shield circuit (grounding body)

Claims (5)

With a shielding structure for a printed circuit board in which a plurality of printed circuit boards (3, 5) provided with a conductive layer (25) on the front surface side of the substrate (21) and a circuit (23) on the back surface side are laminated in the thickness direction. There,
The printed circuit board (3, 5) is laminated in a state where the conductive layer (25) of at least one printed circuit board (3, 5) is arranged on the surface side, and the conductive layer (25 of each printed circuit board (3, 5) ) Is a grounding structure of a printed circuit board.   The shielding structure for a printed circuit board according to claim 1, wherein a grounding body (33) is provided on a side of the circuit (23) on the back surface side of the printed circuit board (3, 5).   The shield structure for a printed circuit board according to claim 1 or 2, wherein the conductive layer (25) is a copper foil, and the circuit (23) is made of a copper foil etched along a pattern.   The said grounding body (33) is a shield circuit which consists of copper foil, The shielding structure of the printed circuit board of Claim 2 characterized by the above-mentioned.   When connecting connectors (11, 13) are provided on the side edges of the printed circuit boards (3, 5) and the printed circuit boards (3, 5) are stacked, the connecting connectors (11, 13) do not overlap. The printed circuit board shielding structure according to any one of claims 1 to 4, wherein directions of the printed circuit boards (3, 5) are alternately arranged.

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