JP2013012528A - Printed board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a printed board which suppresses external electromagnetic noise being transmitted to circuit components.SOLUTION: In a printed board 1 of this invention, multiple conductor layers are laminated with dielectric layers disposed therebetween, and an external interface is mounted on a frame ground pattern 5 formed on a surface of a portion of the conductor layer which is separated through a slit 7. The printed board 1 includes guard patterns 6a, 6b which are provided facing the frame ground pattern 5, are mounted on the conductor layers facing the exterior, and suppressing external electromagnetic noise being transmitted to circuit components.

Description

  The present invention is a print in which a dielectric layer is interposed between a plurality of conductor layers, and an external interface is mounted on a frame ground pattern formed on the surface of a portion of the conductor layer isolated through a slit. Regarding the substrate.

In recent years, electronic devices have been miniaturized and high-density mounting has progressed, and accordingly, the interval between circuit components such as patterns on printed boards and IC components has become narrower, and noise has been easily propagated.
For this reason, external electromagnetic noise such as static electricity is easily propagated into the printed circuit board, and malfunction of circuit components on the printed circuit board is likely to occur.
As a conventional printed circuit board, there is known one in which a slit is provided between a frame ground pattern and a signal ground pattern in order to prevent external electromagnetic noise from propagating onto the printed circuit board (see, for example, Patent Document 1).

JP 2010-50298 A

The printed circuit board of Patent Document 1 is provided with a slit between the frame ground pattern and the signal ground pattern, and the external interface housing mounted on the frame ground pattern includes an external component containing high frequency components (several kHz or more). When electromagnetic noise (for example, electrostatic noise) is applied, most of the electromagnetic noise propagates through the frame ground pattern and propagates to a stable potential such as the ground or the housing of the device.
However, at this time, a part of the electromagnetic noise is spatially coupled to a region where circuit parts such as signal wiring and IC parts are mounted, and there is a problem that the circuit parts on the printed circuit board cause malfunction.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a printed circuit board that reduces the propagation of external electromagnetic noise (for example, electrostatic noise) to circuit components. Yes.

  The printed circuit board according to the present invention includes a guard pattern that is provided facing the frame ground pattern and is mounted on a conductor layer facing the outside.

  According to the printed circuit board of the present invention, the amount of electromagnetic noise coupled to the circuit component from the frame ground pattern can be reduced by the guard pattern, and the reliability against external electromagnetic noise is improved.

It is a top view which shows the printed circuit board of Embodiment 1 of this invention. It is a disassembled perspective view which shows the printed circuit board of FIG. It is arrow sectional drawing along the III-III line | wire of FIG. It is a disassembled perspective view which shows the conventional printed circuit board. It is a figure which shows the comparison of the noise propagation amount of the printed circuit board of Embodiment 1 of this invention, and the conventional printed circuit board. It is a disassembled perspective view which shows the printed circuit board of Embodiment 2 of this invention. It is arrow sectional drawing along the VII-VII line of FIG. It is a disassembled perspective view which shows the printed circuit board of Embodiment 3 of this invention. It is a disassembled perspective view which shows the printed circuit board of Embodiment 4 of this invention. It is arrow sectional drawing along the XX line of FIG. It is a disassembled perspective view which shows the modification of the printed circuit board of Embodiment 4 of this invention. It is a disassembled perspective view which shows the printed circuit board of Embodiment 5 of this invention. It is arrow sectional drawing along the XIII-XIII line | wire of FIG. It is a disassembled perspective view which shows the printed circuit board of Embodiment 6 of this invention. It is arrow sectional drawing along the XV-XV line | wire of FIG. It is a disassembled perspective view which shows the printed circuit board of Embodiment 7 of this invention. It is a disassembled perspective view which shows the printed circuit board of Embodiment 8 of this invention. It is a top view which shows the printed circuit board of Embodiment 9 of this invention. It is a disassembled perspective view which shows the printed circuit board of FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding members and parts will be described with the same reference numerals.
Embodiment 1 FIG.
FIG. 1 is a top view showing a printed circuit board 1 according to Embodiment 1 of the present invention, and FIG. 2 is an exploded perspective view showing the printed circuit board 1 of FIG.
This printed circuit board 1 has a dielectric layer (not shown) between the conductor layers of the first conductor layer, the second conductor layer, the third conductor layer, and the fourth conductor layer on the bottom floor. Intervene.
This printed circuit board 1 has a frame ground pattern 5 on a region 2 where a signal wiring, a signal ground pattern 9 and a power supply pattern 20 are formed on a conductive layer, and a region separated by a slit 7 in a third conductor layer. The first guard pattern 6a and the second guard pattern 6b are formed on the second conductor layer and the fourth conductor layer so as to face the frame ground pattern 5, respectively. It is divided into three.
In the region 2, a circuit component (not shown) such as an IC component is mounted in the region 2 of the first conductor layer and the fourth conductor layer.
The frame ground pattern 5 in the region 3 is connected to a stable potential 10 such as a ground provided on the conductor layer or a housing of the device, and an external interface (not shown) such as a connector or a switch is mounted. The

The first guard pattern 6a and the second guard pattern 6b are electrically connected via vias 8 extending across both sides of the frame ground pattern 5, as shown in FIG.
The first guard pattern 6 a and the second guard pattern 6 b are larger than the projected area of the frame ground pattern 5 and cover the entire area of the frame ground pattern 5.
The first guard pattern 6 a is provided on the same conductor layer as the second conductor layer on which the signal ground pattern 9 is provided, and is electrically connected to the signal ground pattern 9.
The first guard pattern 6 b is provided in the same conductor layer as the fourth conductor layer in which the signal ground pattern 9 is provided, and is electrically connected to the signal ground pattern 9.

In the printed circuit board 1 configured as described above, when external electromagnetic noise (for example, electrostatic noise) including a high-frequency component (several kHz or more) is applied to the housing of the external interface, most of the electromagnetic noise is Then, it propagates through the frame ground pattern 5 and propagates to a stable potential 10 such as the ground or the housing of the device.
Further, although a part of the electromagnetic noise is spatially coupled to the region 2 where the circuit component is mounted, the spatial coupling of the electromagnetic noise to the region 2 is reduced by the first guard pattern 6a and the second guard pattern 6b. be able to. In other words, propagation of electromagnetic noise to the circuit components can be reduced by the first guard pattern 6a and the second guard pattern 6b.

The inventor of the present application transmits noise to each region 2 of the printed circuit board 1 of the first embodiment and the printed circuit board 100 that does not have the first guard pattern 6a and the second guard pattern 6b shown in FIG. The quantity was determined by electromagnetic field analysis.
FIG. 5 shows the analysis result at this time, and the case of the printed circuit board 1 without the first guard pattern 6a and the second guard pattern 6b is set as a noise propagation amount reference (0 dB).
In the frequency region shown in FIG. 5, it can be seen that the amount of noise propagation to the region 2 is smaller in the printed circuit board 1 than in the printed circuit board 100.
That is, when external electromagnetic noise is applied to the housing of the external interface, the printed circuit board 1 of the first embodiment causes malfunction of circuit components on the printed circuit board 1 as compared with the conventional printed circuit board 100. I find it difficult.

Embodiment 2. FIG.
FIG. 6 is an exploded perspective view showing a printed circuit board 1 according to Embodiment 2 of the present invention.
In this embodiment, the first guard pattern 6a and the second guard pattern 6b are not electrically connected to the signal ground pattern 9 provided in a part of the region 2 of the conductor layer.
Further, the first guard pattern 6a and the second guard pattern 6b are not electrically connected.
Further, as shown in FIG. 7, the width dimensions of the first guard pattern 6 a and the second guard pattern 6 b are the same as the width dimensions of the frame ground pattern 5.
Other configurations are the same as those of the printed circuit board 1 of the first embodiment.

In this embodiment, the first guard pattern 6a and the second guard pattern 6b are not electrically connected to the signal ground pattern 9, and the first guard pattern 6a and the second guard pattern 6b are different from each other. Although not electrically connected, the first guard pattern 6a and the second guard pattern 6b reduce the spatial coupling of the electromagnetic noise to the region 2 (in other words, the propagation of the electromagnetic noise to the circuit component is reduced). Thus, malfunction of circuit components can be reduced.
Further, the size of the printed circuit board 1 can be reduced by the amount that the width dimensions of the guard patterns 6a and 6b are made smaller than that of the printed circuit board 1 of the first embodiment.

Embodiment 3 FIG.
FIG. 8 is an exploded perspective view showing the printed circuit board 1 according to the third embodiment of the present invention.
In this embodiment, the first guard pattern 6a is disposed only on the upper side of the frame ground pattern 5, and the second guard pattern 6b is not provided on the lower side.
Other configurations are the same as those of the printed circuit board 1 of the second embodiment.
Note that the second guard pattern 6a may be disposed below the frame ground pattern 5 except for the first guard pattern 6a.
In this embodiment, although the effect of reducing the coupling of electromagnetic noise to the region 2 described above is inferior to that of the printed circuit board 1 of the second embodiment, the guard pattern is reduced and the manufacturing cost is reduced.

Embodiment 4 FIG.
FIG. 9 is an exploded perspective view showing a printed circuit board 1 according to Embodiment 4 of the present invention.
In this embodiment, the width dimension of the first guard pattern 6 a and the second guard pattern 6 b is larger than the width dimension of the frame ground pattern 5.
That is, the first guard pattern 6 a and the second guard pattern 6 b are larger than the projected area of the frame ground pattern 5 and cover the entire area of the frame ground pattern 5.
Other configurations are the same as those of the printed circuit board 1 of the second embodiment.

According to the printed circuit board 1 of this embodiment, the first guard pattern 6a and the second guard pattern 6b are made larger than the projected area of the frame ground pattern 5, and the electromagnetic waves from the frame ground pattern 5 to the region 2 are increased. Noise coupling can be further reduced as compared with the printed circuit board 1 of the second and third embodiments.
Note that only one width dimension of the guard patterns 6 a and 6 b may be larger than the width dimension of the frame ground pattern 5.
For example, as shown in FIG. 11, the printed circuit board 1 may be the printed circuit board 1 in which the first guard pattern 6 a is left from the printed circuit board 1 in FIG. 9 and the second guard pattern 6 b is removed.

Embodiment 5 FIG.
12 is an exploded perspective view showing the printed circuit board 1 according to the fifth embodiment of the present invention, and FIG. 13 is a cross-sectional view taken along the line XIII-XIII in FIG.
In this embodiment, the first guard pattern 6a and the second guard pattern 6b are connected by a via 8 penetrating the frame ground pattern 5 and the conductor layer.
Further, the first guard pattern 6 a and the second guard pattern 6 b are larger than the projected area of the frame ground pattern 5.
Other configurations are the same as those of the printed circuit board 1 of the second embodiment.

  In this embodiment, since the first guard pattern 6a and the second guard pattern 6b are electrically connected by the via 8, the first guard pattern 6a and the second guard pattern 6b are equipotential. Thus, the coupling of electromagnetic noise from the frame ground pattern 5 to the region 2 can be further reduced as compared with the printed circuit board 1 of the second and fourth embodiments.

Embodiment 6 FIG.
14 is an exploded perspective view showing the printed circuit board 1 according to the sixth embodiment of the present invention, and FIG. 15 is a cross-sectional view taken along the line XV-XV in FIG.
In this embodiment, the first guard pattern 6 a and the second guard pattern 6 b are connected by vias 8 extending in the vertical direction across both sides of the frame ground pattern 5.
Further, the first guard pattern 6 a and the second guard pattern 6 b are larger than the projected area of the frame ground pattern 5.
Other configurations are the same as those of the printed circuit board 1 of the second embodiment, and the same effects as those of the fifth embodiment can be obtained.

Embodiment 7 FIG.
FIG. 16 is a perspective view showing a printed circuit board 1 according to the seventh embodiment of the present invention.
In this embodiment, the guard patterns 6 a and 6 b are provided on the same conductor layer as the second and fourth conductor layers on which the power supply pattern 20 is provided, and are electrically connected to the power supply pattern 20.
Other configurations are the same as those of the printed circuit board 1 of the first embodiment, and the same effects as those of the printed circuit board 1 of the first embodiment can be obtained.

In addition, when the signal ground pattern 9 and the power supply pattern 20 are formed on the same conductor layer, and the power supply pattern 20 has a larger area than the signal ground pattern 9, the large area causes the influence of, for example, voltage vibration due to noise. Therefore, the guard patterns 6a and 6b are preferably electrically connected to the power supply pattern 20.
However, when the power supply pattern 20 and the signal ground pattern 9 have the same area, the signal ground pattern 9 is designed to suppress the influence of noise voltage oscillation, so that the guard patterns 6a and 6b are It is preferable to electrically connect to the signal ground pattern 9.

Embodiment 8 FIG.
FIG. 17 is an exploded perspective view showing the printed circuit board 1 according to the eighth embodiment of the present invention.
In this embodiment, the first guard pattern 6 a is electrically connected to the signal ground pattern 9 via the electronic device 11.
There may be a plurality of electronic devices 11 or different types of electronic devices 11.
The electronic device 11 is a capacitor, an inductor, or a resistor, for example.

  According to the printed circuit board 1 according to this embodiment, the frequency characteristics of electromagnetic noise differ depending on the installation environment. By selecting the electronic device 11 corresponding to the frequency characteristics, the amount of noise propagation to the region 2 The malfunction of the circuit component on the printed circuit board 1 can be further reduced.

Embodiment 9 FIG.
18 is a top view showing a printed circuit board 1 according to Embodiment 9 of the present invention, and FIG. 19 is an exploded perspective view showing the printed circuit board 1 in FIG.
In this embodiment, the frame ground pattern 5 is L-shaped, and the external interface 4 is provided at the tip of the frame ground pattern 5. The first guard pattern 6a and the second guard pattern 6a are formed in accordance with this shape. The guard pattern 6b is also L-shaped.
The first guard pattern 6 a and the second guard pattern 6 b are larger than the projected area of the frame ground pattern 5 and cover the entire area of the frame ground pattern 5.
Other configurations are the same as those of the printed circuit board 1 of the first embodiment, and the same effects as those of the printed circuit board 1 of the first embodiment can be obtained.

In the printed circuit board 1 of each of the embodiments described above, the conductor layers are all four layers, but the present invention is not limited to this.
The frame ground pattern 5 is formed on the third conductor layer, but may be formed on another conductor layer.
Moreover, the 1st guard pattern 6a and the 2nd guard pattern 6b may be laminated | stacked continuously by multiple layers.

  1 printed circuit board, 2, 3 area, 4 external interface, 5 frame ground pattern, 6a first guard pattern, 6b second guard pattern, 7 slit, 8 via, 9 signal ground pattern, 10 stable potential, 11 electrons Device, 20 power pattern.

Claims (14)

A printed circuit board in which a dielectric layer is interposed between a plurality of conductor layers and an external interface is mounted on a frame ground pattern formed on a surface of a portion of the conductor layer separated by a slit. ,
A printed circuit board comprising a guard pattern provided facing the frame ground pattern and mounted on the conductor layer facing outward.   The printed circuit board according to claim 1, wherein the guard pattern is larger than a projected area of the frame ground pattern and covers the entire area of the frame ground pattern.   The printed circuit board according to claim 1, wherein the guard pattern is a single body.   The printed circuit board according to any one of claims 1 to 3, wherein the guard pattern is continuously laminated in a plurality of layers.   The guard patterns are a first guard pattern and a second guard pattern disposed opposite to both sides of the frame ground pattern, respectively, and the first guard pattern and the second guard pattern are The printed circuit board according to claim 1, wherein the printed circuit board is electrically connected by a via.   The printed circuit board according to claim 5, wherein the first guard pattern and the second guard pattern are electrically connected through the vias extending across the frame ground pattern.   The printed circuit board according to claim 5, wherein the first guard pattern and the second guard pattern are electrically connected by the via extending through the frame ground pattern. .   The guard pattern is provided in the conductor layer provided with a signal ground pattern and a power supply pattern, and is electrically connected to a signal ground pattern or a pattern having a large area among the power supply patterns. The printed circuit board according to any one of 1 to 7.   The print according to any one of claims 1 to 7, wherein the guard pattern is provided on the conductor layer provided with a signal ground pattern and is electrically connected to the signal ground pattern. substrate.   The printed circuit board according to claim 1, wherein the guard pattern is provided on the conductor layer provided with a power supply pattern and is electrically connected to the power supply pattern.   The printed circuit board according to claim 8, wherein the guard pattern is connected to the signal ground pattern via an electronic device corresponding to the frequency characteristics of the electromagnetic noise.   The printed circuit board according to claim 11, wherein the electronic device is a capacitor.   The printed circuit board according to claim 11, wherein the electronic device is an inductor.   The printed circuit board according to claim 11, wherein the electronic device is a resistor.

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