JP2006319013A - Single-sided printed wiring board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a single-sided printed wiring board which is inexpensive, and sufficiently reduces radiant noises caused by high-frequency signal return currents flowing through a high-frequency hardwire. <P>SOLUTION: The single-sided printed wiring board 10 is constructed by forming a conductor pattern hardwire 13, which serves as a current path for a high-frequency signal, only on one surface of a board body 12 that is made of an insulator. A conductive sheet member 15 is attached to the other surface of the board body 12 and is electrically connected to ground regions 13b, 13d of the conductor pattern wiring 13 on one surface of the board body 12 via metal wire 16, which is inserted via through-holes 14a, 14b of the board body 12. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a single-sided printed wiring board, and more particularly to a single-sided printed wiring board that can reduce radiation noise due to a return current of a high-frequency signal flowing through a high-frequency wiring.

  In a printed wiring board having a conductor pattern wiring (hereinafter referred to as “high-frequency wiring”) such as a bus line or a clock line that serves as a current path for a high-frequency signal, radiation noise is generated by a return current of the high-frequency signal flowing through the high-frequency wiring. In the case of a multilayer printed wiring board or a double-sided printed wiring board, the radiation noise can be easily reduced because a microstrip structure can be formed relatively easily.

  For example, in the case of a multilayer printed circuit board, a flat conductor facing the high-frequency wiring is provided in the inner ground layer or power supply layer with an insulator constituting a part of the substrate body sandwiched between the high-frequency wiring in the outer layer. Thus, the microstrip structure can be easily configured.

  In the case of a double-sided printed wiring board, a microstrip structure can be easily configured by forming a ground pattern made of a conductor on the back surface of the board main body for high-frequency wiring formed on the surface of the board main body. .

  On the other hand, in the case of a single-sided printed wiring board, in general, by securing the width of the ground pattern as a return current path of the high-frequency signal flowing through the high-frequency wiring as wide as possible, by reducing the impedance of the return current path, Radiation noise due to return current is reduced.

Further, as a means for reducing the radiation noise in a single-sided printed wiring board, there is a noise countermeasure component 101 disposed on the single-sided printed wiring board 100 as shown in FIG. 9 (see, for example, Patent Document 1). This noise countermeasure component 101 is obtained by attaching an insulator 103 to the lower surface of a wide conductor 102 and is disposed so as to straddle the conductor pattern wiring 104 through which a high-frequency signal flows. It is electrically connected to the ground region 105. Therefore, the noise countermeasure component 101 functions as a return current path, and radiation noise due to the return current can be reduced.
Japanese Patent Laid-Open No. 8-250891

  However, in a single-sided printed circuit board, if there is not enough space to ensure that the ground pattern is wide enough on the board, the ground pattern is widened as described above and the radiated noise caused by the return current It is not possible to use a method for reducing the above.

  Further, for example, like a single-sided printed wiring board 110 shown in FIG. 10, a high-frequency signal is generated between a land 112a to which the ground terminal of the IC 111a is directly connected and a land 112b to which the ground terminal of the electronic component 111b is directly connected. When the flowing pattern wiring 113 is arranged, it is necessary to form the ground pattern 114 serving as a return current path so as to bypass the pattern wiring 113, resulting in a large loop of the return current path, and as a result, radiation due to the return current. There is a possibility that noise cannot be reduced sufficiently.

  On the other hand, when the noise countermeasure component 101 is arranged as in the single-sided printed wiring board 100, a complicated process of arranging the noise countermeasure component 101 so as to straddle the conductor pattern wiring 104 is necessary. Therefore, there is a problem that the manufacturing cost is increased.

  The present invention has been made to solve such a problem, and an object thereof is to provide a single-sided printed wiring board that is inexpensive and can sufficiently reduce radiation noise due to a return current of a high-frequency signal flowing through a high-frequency wiring. And

  In order to achieve the above object, the single-sided printed wiring board according to claim 1 is a single-sided printed wiring board in which a conductor pattern wiring serving as a current path for high-frequency signals is formed only on one side of a board body formed of an insulator. In the printed wiring board, the conductive sheet member is attached to the other surface of the substrate body, and the conductive sheet member and the ground area of the conductor pattern wiring on one surface of the substrate body are connected to the substrate body. It is characterized in that it is electrically connected through a metal wire inserted through the through hole.

  The single-sided printed wiring board according to claim 2 is the single-sided printed wiring board according to claim 1, wherein at least a region facing the conductor pattern wiring is provided on the other surface of the board body with the board body interposed therebetween. The conductive sheet member is attached so as to include it.

  A single-sided printed wiring board according to a third aspect is the single-sided printed wiring board according to the first aspect, wherein at least a space between the grounding regions of the conductor pattern wiring is sandwiched between the other side of the board body and the board body. The conductive sheet member is attached so as to include a region facing a region that is linearly connected.

  5. The single-sided printed wiring board according to claim 4, wherein a conductor pattern wiring that forms a current path for a high-frequency signal is formed only on one surface of the board main body formed of an insulator. A portion of one surface side of the substrate body of the metal wire inserted through the through hole of the metal wire is electrically connected to a ground region of the conductor pattern wiring on the one surface, and the substrate of the metal wire A portion on the other surface side of the main body is electrically connected to a conductive casing of an apparatus including the single-sided printed wiring board.

  According to the single-sided printed wiring board of the first aspect, the conductive sheet member can be used as a return current path between the ground areas of the conductor pattern wiring. In addition, since this conductive sheet member is attached to the surface where the conductor pattern wiring is not formed, a sufficient return current path can be secured and the ground pattern formed so as to bypass the conductor pattern wiring. Since the loop of the return current path is smaller than the case where the return current path is used, the radiation noise due to the return current can be sufficiently reduced. In addition, since the conductive sheet member and the ground area of the conductor pattern wiring are electrically connected via a metal wire inserted through the through hole of the board body, the increase in manufacturing cost is suppressed, and one side A printed wiring board can be manufactured at low cost.

  According to the single-sided printed wiring board according to claim 2, since the conductive sheet member is attached at least in a region facing the conductor pattern wiring with the board body interposed therebetween, it is likely to flow along the conductor pattern wiring. The radiation noise due to the return current can be sufficiently reduced. Further, if the conductive sheet member is not attached to a region other than the opposed region, the region (space) can be effectively used for installation of electronic components, for example.

  According to the single-sided printed wiring board according to claim 3, since the conductive sheet member is attached at least in a region facing the region that linearly connects the ground regions of the conductor pattern wiring with the substrate body interposed therebetween. The loop of the return current path becomes small, and the radiation noise due to the return current can be sufficiently reduced. Further, since it is not necessary to use a large conductive sheet member, it is possible to reduce the cost required for reducing radiation noise. Further, if the conductive sheet member is not attached to a region other than the opposed region, the region (space) can be effectively used for installation of electronic components, for example.

  According to the single-sided printed wiring board of the fourth aspect, the conductive casing of the device including the single-sided printed wiring board can be used as a return current path between the ground regions of the conductor pattern wiring. Therefore, a sufficient return current path can be ensured, and radiation noise due to the return current can be sufficiently reduced. In addition, it is a simple configuration in which the housing and the ground area of the conductor pattern wiring are electrically connected via a metal wire inserted through the through hole of the substrate body, and it is necessary to form a ground pattern or the like on the substrate. Therefore, an increase in manufacturing cost can be suppressed and a single-sided printed wiring board can be manufactured at low cost.

  Hereinafter, a single-sided printed wiring board according to a first embodiment of the present invention will be described with reference to the drawings. As shown in FIGS. 1 to 3, a part of this single-sided printed wiring board 10 is a single-sided printed circuit in which chip-formed electronic components 11 (11a and 11b) are mounted only on the surface by surface mounting technology (SMT). It is a wiring board. Here, an IC (Integrated Circuit) 11 a and other electronic components 11 b are mounted as the electronic components 11. The single-sided printed wiring board 10 includes a board body 12, conductor pattern wirings 13 (13a to 13e) formed only on the surface (one side) of the board body 12, and a plurality of through holes provided in the board body 12. 14 (14a and 14b), a conductive sheet (conductive sheet member) 15 attached to the back surface (the other surface) of the substrate body 12, and a metal wire 16 inserted through the through hole 14. Yes.

The substrate body 12 is formed of an insulator having high insulation properties such as paper epoxy resin (insulation resistance of 10 ⁵ MΩ or more) and paper phenol resin (insulation resistance of 10 ³ to 10 ⁵ MΩ or more).

  The conductor pattern wiring 13 is formed of a conductor such as copper foil on the surface of the substrate body 12, and here, as shown in the figure, lands 13a to 13d and a pattern wiring 13e are formed as the conductor pattern wiring 13. ing. The land 13a is a land to which each terminal excluding the ground terminal of the IC 11a is electrically directly connected. The land 13b is a grounding region to which the ground terminal of the IC 11a is directly electrically connected, and is formed so as to extend from the land 13a so as to surround the open portion while opening the upper portion of the through hole 14a. The land 13c is a land to which each terminal excluding the ground terminal of the electronic component 11b is electrically directly connected. The land 13d is a grounding region to which the ground terminal of the electronic component 11b is directly connected. The land 13d is formed to extend from the land 13c so as to surround the open portion while opening the upper portion of the through hole 14b. . The pattern wiring 13e is electrically connected between the land 13a and the land 13c, and serves as a current path for a high-frequency signal between the IC 11a and the electronic component 11b (hereinafter also referred to as “high-frequency wiring”). ).

  The through hole 14 is formed so as to penetrate perpendicularly to the substrate body 12. Here, as shown in the drawing, the through hole 14 is a through hole whose upper end on the surface side of the substrate body 12 is surrounded by a land 13 b. A hole 14a and a through hole 14b in which the upper end of the surface side of the substrate body 12 is surrounded by the land 13d are provided. These through holes 14a and 14b are normal holes (non-through holes) formed in the substrate body 12 by a drill or the like and not plated or the like.

  The conductive sheet 15 is a sheet-like member made of a conductive material such as copper, gold, and aluminum, and covers a wide area including areas facing the lands 13a to 13d and the pattern wiring 13e across the substrate body 12. It is attached so as to be in contact with the back surface of the substrate body 12. The conductive sheet 15 is provided with holes for inserting the metal wires 16 below the through holes 14a and 14b. The method of attaching the conductive sheet 15 to the back surface of the substrate body 12 is not particularly limited, and may be attached by adhesion, sticking, mechanical urging, or the like using a conductive adhesive, for example.

  The metal wire 16 is a linear member made of a metal such as iron, copper, gold, and aluminum. For example, a wire used as a jumper wire can be used. The metal wire 16 is inserted into the through holes 14a and 14b while being in close contact with the conductive sheet 15 from below the substrate body 12 so as to be directly electrically connected to the conductive sheet 15, and the lands 13b and 13d. Are joined to the lands 13b and 13d by solder 17 so as to be directly connected to each other.

  The substrate body 12 is made of an insulator such as a paper epoxy resin having a dielectric constant of 5 or more and 5.5 or less, or a paper phenol resin having a dielectric constant of 4.6 or less. Since the conductive sheet 15 attached so as to face the pattern wiring 13e across the substrate body 12 having such a dielectric constant is attached to the back surface of the substrate body 12, the conductive pattern wiring 13 etc. Without being restricted, the area can be secured sufficiently wide with respect to the lands 13a to 13d and the pattern wiring 13e. In such a case, the single-sided printed wiring board 10 can be regarded as a microstrip structure. As shown in FIG. 3, the conductive sheet 15 serves as a current path for a return current Ir that flows in a direction opposite to the current Io of the high-frequency signal that flows through the pattern wiring 13e. Further, a sufficient area as a return current path is secured by the conductive sheet 15, and as shown in FIG. 10, a ground pattern 114 is formed so as to bypass the pattern wiring 113, and this ground pattern 114 is returned to the return current. Compared with the case where the path is used, the loop of the return current path becomes smaller, and the radiation noise due to the return current Ir of the high-frequency signal current Io flowing through the pattern wiring 13e can be sufficiently reduced.

  In addition, since a sufficient area as a return current path is secured in the conductive sheet 15, the thickness of the conductive sheet 15 can be reduced, and even if the conductive sheet 15 is attached, the single-sided printed wiring board 10 is provided. The overall thickness does not change much. Therefore, even when there is not much room in the thickness direction, radiation noise due to the return current Ir of the high-frequency signal flowing through the pattern wiring 13e can be reduced.

  Moreover, like the single-sided printed wiring board 10 'shown in FIG. 4, a conductive sheet is provided below the metal wire 16' inserted through the through holes 14a and 14b and joined to the lands 13b and 13d by the solder 17. The conductive sheet 15 ′ may be attached so that 15 ′ is brought into close contact and electrically connected directly to the metal wire 16 ′. In this case, it is not necessary to make a hole for inserting the metal wire 16 ′ into the conductive sheet 15 ′, and the conductive sheet 15 ′ and the metal are attached to the conductive sheet 15 ′ so as to apply a predetermined tension or more. The wire 16 'can be reliably electrically connected.

  In the case where the area of the conductive sheet 15 cannot be sufficiently large due to the reason that electronic components are installed on the back surface of the substrate body 12, for example, the single-sided printed wiring board 20 shown in FIG. As described above, the conductive sheet 25 having a size (area) different from that of the conductive sheet 15 is attached to the back surface of the substrate body 12 so as to include at least a region facing the pattern wiring 13e with the substrate body 12 interposed therebetween. Also good. Thus, if the area of the conductive sheet 25 can be secured so as to cover at least the region facing the pattern wiring 13e, the return current due to the conductive sheet 25 flowing along the pattern wiring 13e through which the high-frequency signal flows can be obtained. Radiation noise can be sufficiently reduced.

  Further, for example, the board main body includes at least a region facing a region linearly connecting the land 13b and the land 13d with the substrate main body 12 interposed therebetween, such as the single-sided printed wiring board 30 shown in FIG. A conductive sheet 35 having a certain width may be attached to the back surface of the twelve. This conductive sheet 35 differs from the conductive sheet 15 only in size (area), and the return current path of the high-frequency signal flowing through the pattern wiring 13e is the same as that in the conventional single-sided printed wiring board 110 shown in FIG. Compared with the ground pattern 114 which is a return current path, it can be made sufficiently short. Therefore, by ensuring the width of the conductive sheet 35 at a certain level or more, it is possible to sufficiently reduce the radiation noise due to the return current of the high-frequency signal flowing through the pattern wiring 13e.

  Hereinafter, a single-sided printed wiring board according to a second embodiment of the present invention will be described with reference to the drawings. This single-sided printed wiring board 40 has through-holes in the board body 12 instead of the conductive sheets 15, 25, 35 in the first embodiment, as shown in FIG. 14 (14a and 14b), the portion of the metal wire 46 on the back surface (the other surface) side of the substrate body 12 is electrically connected to the conductive housing 45 of the apparatus including the single-sided printed wiring board 40. To be connected.

  The conductive housing 45 is a part of an apparatus including the single-sided printed wiring board 40, and covers a wide area including areas facing the lands 13a to 13d and the pattern wiring 13e with the board body 12 interposed therebetween. 12 is arranged so as to directly face the back surface of the twelve. Even if the entire case 45 is formed of a sheet metal made of a conductive material such as iron, copper, gold, or aluminum, the casing 45 is electrically conductive on the surface facing the back surface of the substrate body 12. A sheet may be attached, and the shape is not particularly limited.

  The metal wire 46 is inserted into the through holes 14a and 14b while being in close contact with the lower surface of the substrate body 12, and is joined to the lands 13b and 13d by solder 47 so as to be directly connected to the lands 13b and 13d. ing. The single-sided printed wiring board 40 is attached from above the housing 45 so that the housing 45 is electrically directly connected to the metal wire 46 that is in close contact with the lower surface of the substrate body 12. The method of attaching the single-sided printed wiring board 40 to the housing 45 is not particularly limited, and may be attached by adhesion, sticking, mechanical urging, or the like with a conductive adhesive, for example.

  In the single-sided printed wiring board 40 as well, like the conductive sheet 15, the housing 45 is not limited by the space due to the conductor pattern wiring 13 or the like, and the area of the housing 45 is limited to the lands 13 a to 13 d and the pattern wiring 13 e. Enough can be secured. In such a case, the single-sided printed wiring board 40 can be regarded as a microstrip structure. And the housing | casing 45 becomes a path | route of the return electric current which flows into the opposite direction to the electric current of the high frequency signal which flows through the pattern wiring 13e. In addition, since a sufficient area as a return current path is secured by the conductive casing 45, radiation noise due to the return current of the high-frequency signal current flowing through the pattern wiring 13e can be sufficiently reduced.

  Further, since the housing 45 of the apparatus having the single-sided printed wiring board 40 is used as a return current path, it is not necessary to add another member such as the conductive sheet 15 and is necessary to reduce radiation noise due to the return current. Cost can be reduced.

  Hereinafter, a multilayer printed wiring board provided with a return current path such as the conductive sheet 15 will be described with reference to the drawings. As shown in FIGS. 8A and 8B, a part of the multilayer printed wiring board 50 is provided with ground regions 53a and 53b on two inner layers of a ground layer 51 and a power supply layer 52 and an outer layer on the surface. It is a printed wiring board which has the conductor pattern wiring containing this.

  The ground layer 51 and the power supply layer 52 are formed with an insulating layer interposed therebetween. In some cases, a long clearance hole 54 may be provided in the ground layer 51 or the power supply layer 52. In such a case, the microstrip structure cannot be configured using the ground layer 51 and the power supply layer 52. Then, when vias (not shown) are formed in the ground layer 51 from the ground areas 53a and 53b of the conductor pattern wiring on the surface through the insulating layer therebetween, the return between the ground areas 53a and 53b of the conductor pattern wiring via this via. Since the current path passes through the ground layer 51 around the long clearance hole 54 as shown by a two-dot chain line in FIG. 8B, the loop becomes large.

  Therefore, as shown in the figure, a conductor pattern wiring 55 made of copper foil is formed on the back surface of the substrate body, and this conductor pattern wiring 55 and the grounding regions 53a and 53b of the conductor pattern wiring on the front surface are formed through the substrate body. The vias 56a and 56b are electrically connected to each other. These vias 56a and 56b are formed so as to face the short direction in the middle of the long clearance hole 54 in the longitudinal direction, and the conductor pattern wiring 55 passes below the clearance hole 54. Therefore, the return current of the high-frequency signal flowing between the ground areas 53 a and 53 b of the conductor pattern wiring on the surface can use the conductor pattern wiring 55 and the vias 56 a and 56 b as a route, and the clearance hole 54 is formed in the ground layer 51. Since there is no need to bypass, the return current path loop becomes smaller. Therefore, noise due to the return current of the high frequency signal flowing between the ground regions 53a and 53b of the conductor pattern wiring can be reduced.

1 is a schematic surface view showing a part of a single-sided printed wiring board 10 according to a first embodiment of the present invention. It is a schematic longitudinal cross-sectional view in the AA cross section shown in FIG. 1 of the single-sided printed wiring board 10. FIG. FIG. 2 is a schematic vertical cross-sectional view of the single-sided printed wiring board 10 taken along the line BB shown in FIG. 1. It is a schematic surface drawing which shows a part of single-sided printed wiring board 10 'which concerns on the deformation | transformation of the 1st Embodiment of this invention. It is a schematic surface drawing which shows a part of the single-sided printed wiring board 20 which concerns on other deformation | transformation of the 1st Embodiment of this invention. It is a schematic surface view which shows a part of single-sided printed wiring board 30 which concerns on another deformation | transformation in the 1st Embodiment of this invention. It is a schematic longitudinal cross-sectional view which shows a part of single-sided printed wiring board 40 concerning the 2nd Embodiment of this invention. A part of multilayer printed wiring board 50 is shown, (a) is a schematic surface view, (b) is a schematic longitudinal cross-sectional view in CC section shown to (a). It is a schematic longitudinal cross-sectional view which shows a part of conventional single-sided printed wiring board 100. It is a schematic surface view which shows a part of another conventional single-sided printed wiring board 110.

Explanation of symbols

10, 10 ', 20, 30, 40 Single-sided printed wiring board 12 Substrate body 13 Conductor pattern wiring 13b, 13d Land (grounding area)
13e Pattern wiring (conductor pattern wiring)
14 Through-holes 14a, 14b Through-holes 15, 15 ', 25, 35 Conductive sheet (conductive sheet member)
16, 16 ', 46 Metal wire 45 Case

Claims (4)

In the single-sided printed wiring board in which the conductor pattern wiring that becomes the current path of the high-frequency signal is formed only on one surface of the substrate body formed of the insulator,
The conductive sheet member is attached to the other surface of the substrate body, and the conductive sheet member and the ground area of the conductor pattern wiring on one surface of the substrate body are inserted through the through holes of the substrate body. A single-sided printed wiring board characterized in that it is electrically connected via a metal wire.   The single-sided print according to claim 1, wherein the conductive sheet member is attached to the other surface of the substrate body so as to include at least a region facing the conductor pattern wiring with the substrate body interposed therebetween. Wiring board.   The conductive sheet member is attached to the other surface of the substrate body so as to include at least a region opposed to a region that linearly connects the ground regions of the conductor pattern wiring with the substrate body interposed therebetween. The single-sided printed wiring board according to claim 1, wherein: In the single-sided printed wiring board in which the conductor pattern wiring that becomes the current path of the high-frequency signal is formed only on one surface of the substrate body formed of the insulator,
A portion of one side of the substrate main body of the metal wire inserted through the through hole of the substrate main body is electrically connected to a ground region of the conductor pattern wiring on the one surface, and the metal wire A single-sided printed wiring board, wherein a portion of the other side of the board body is electrically connected to a conductive casing of an apparatus including the single-sided printed wiring board.

Images