JPH11261285A - Electromagnetic shielding structure and electronic equipment using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electromagnetic shielding structure preventing propagation of noise between one main surface and the other main surface of a substrate. SOLUTION: A substrate 2 where an electronic component 9 is mounted on one main surface 2a and an electronic component 12 is mounted on the other main surface 2b is arranged in a chassis 13. A first and a second penetrating holes 21 and 22 are formed at the upper part and the lower part from the substrate 2 of the chassis 13, and penetrating capacitors 23 and 24 are inserted. One terminal 23a of the penetrating capacitor 23 is connected with a wiring electrode 4, and one terminal 24a of the penetrating capacitor 24 is connected with a wiring electrode 5, respectively. The other terminals 23b and 24b of the penetrating capacitors 23 and 24 are connected with each other in the outside of the chassis 13. As a result, propagation of noise between the one main surface 2a of the substrate 2 on which the electronic component 9 is mounted and the other main surface 2b of the substrate 2 on which the electronic component 12 is mounted can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic shielding structure and an electronic device using the same, and more particularly to an electromagnetic shielding structure used for digital equipment and high-frequency communication equipment and an electronic device using the same.

[0002]

2. Description of the Related Art With the recent increase in the frequency of digital equipment and communication equipment, the problem of interference in another circuit due to noise generated in one circuit in the equipment has been increasing. I'm in a hurry.

FIG. 8 is a sectional view of a conventional electromagnetic shielding structure for preventing propagation of noise between one main surface and the other main surface of a substrate. In the electromagnetic shielding structure 1 of FIG. 8, the substrate 2 has a ground electrode layer 3 inside, and a wiring electrode 4 is formed on one main surface 2a and a wiring electrode 5 is formed on the other main surface 2b. A ground electrode 6 is also formed on one main surface 2 a and the other main surface 2 b of the substrate 2, and is electrically connected to the ground electrode layer 3 by a via hole 7. The wiring electrode 4 and the wiring electrode 5 are connected by a through hole 8 formed through the substrate 2. On one main surface 2a of the substrate 2, the first
The electronic component 9 and the noise filter 10 constituting the circuit are mounted on the wiring electrode 4 by the solder 11. On the other main surface 2 b of the substrate 2, an electronic component 12 constituting a second circuit is mounted on the wiring electrode 5 by solder 11. The end of the substrate 2 is a metal chassis 13.
The substrate 2 is fixed to the chassis 13 by electrically connecting the ground electrodes 6 formed on both surfaces of the substrate 2 to the chassis 13 with solder 11. In FIG. 8, only one end of the substrate 2 is connected to the chassis 13, but the entire periphery of the substrate 2 is similarly connected to the chassis 13, and the inside of the chassis 13 is vertically separated by the substrate 2. ing. Although not shown in FIG. 8, the chassis 13 has an upper surface and a bottom surface, and the substrate 2 is provided in parallel with the upper surface and the bottom surface of the chassis 13.

FIG. 9 shows an electrical connection relationship of the electromagnetic shielding structure 1. As shown in FIG. 9, the electronic component 9 is connected to the electronic component 12 through the noise filter 10 and the through hole 8.
Is connected to Except for the through hole 8, the ground electrode layer 3 of the substrate 2 functions as a shielding plate between the electronic components 9 and 12, thereby preventing mutual electromagnetic interference.

[0005] With this configuration, the one main surface 2a side and the other main surface 2b side of the substrate 2 are electromagnetically shielded, and for example, noise generated in the electronic component 9 is reduced by the noise filter 1.
It is suppressed at 0 so that it is difficult to reach the electronic component 12.

[0006]

However, in the conventional electromagnetic shielding structure 1, the noise generated in the electronic component 9 does not necessarily propagate only through the wiring electrode 4, but is indicated by, for example, an arrow 14 in FIG. Through the air and bypass the noise filter 10 directly through the
May be reached. There is a problem that such noise cannot be removed by the noise filter 10 and reaches the electronic component 12.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, and an electromagnetic shielding structure for preventing propagation of noise between one main surface and the other main surface of a substrate, and an electronic device using the same. I will provide a.

[0008]

In order to achieve the above object, an electromagnetic shielding structure according to the present invention is provided in a chassis having a top surface, a bottom surface, and a side surface, and inside the chassis between the side surfaces of the chassis. A substrate having first and second circuits on one main surface and the other main surface, and having first and second through holes at upper and lower positions with respect to the substrate position on the side surface of the chassis. Forming the first and second noise removing components into the first and second through holes, and connecting one terminal of the first noise removing component to the first circuit and the second noise removing component. One terminal of the removing component is connected to the second circuit, and the other terminals of the first and second noise removing components are connected outside the chassis.

Further, the electromagnetic shielding structure of the present invention has the first
And a ground electrode of the second noise removing component is electrically connected to the chassis.

Further, in the electromagnetic shielding structure of the present invention, a gap between the first and second through holes and the first and second noise removing components is filled with an electric conductor, respectively, and the electric conductor is filled with the electric conductor. It is characterized by being electrically connected to a ground electrode of the first and second noise removing components and the chassis.

Further, the electromagnetic shielding structure of the present invention is provided with a chassis having an upper surface, a bottom surface, and a side surface, a flange protruding from an inner surface of the chassis, and a space inside the chassis between the side surfaces of the chassis. The substrate has first and second circuits on one main surface and the other main surface, and has an end connected to the collar, forming a through hole in the collar. Insert the noise removal parts into the through holes,
One terminal of the noise elimination component is connected to the first circuit, and the other terminal of the noise elimination component is connected to the second circuit.

Further, the electromagnetic shielding structure of the present invention is characterized in that a ground electrode of the noise elimination component is electrically connected to the collar.

In the electromagnetic shielding structure according to the present invention, a gap between the through hole and the noise removing component is filled with an electric conductor,
The electric conductor is electrically connected to a ground electrode and the collar of the noise elimination component.

Further, an electronic device according to the present invention is characterized by being configured using the above-mentioned electromagnetic shielding structure.

With this configuration, in the electromagnetic shielding structure of the present invention, it is possible to prevent propagation of noise between one main surface and the other main surface of the substrate. Further, in the electronic device of the present invention, the plurality of circuits do not become noise sources for each other, and each circuit can always function normally.

[0016]

FIG. 1 is a sectional view showing an embodiment of an electromagnetic shielding structure according to the present invention. In FIG. 1, the same or equivalent parts as those in FIG. 8 are denoted by the same reference numerals, and the description thereof will be omitted.

In the electromagnetic shielding structure 20 shown in FIG. 1, a first through hole 21 and a second through hole 22 are provided above and below the substrate 2 of the chassis 13 in the vicinity of a portion where the chassis 13 and the substrate 2 are connected. Are formed respectively. The first through hole 21 and the second through hole 22
A feedthrough capacitor 23 as a noise removing component and a feedthrough capacitor 24 as a second noise removing component are respectively inserted. The ground electrodes on the side surfaces of the feedthrough capacitors 23 and 24 are electrically connected to and fixed to the chassis 13 by the solder 1. The lead pin 23a, which is one terminal of the feedthrough capacitor 23, is connected to the wiring electrode 4 formed on the one main surface 2a of the substrate 2, and the feedthrough capacitor 24
Is connected to the wiring electrode 5 formed on the other main surface 2b of the substrate 2, and the lead pin 23a is the other terminal of the feedthrough capacitors 23 and 24.
b and 24b are electrically connected to each other outside the chassis 13.

FIG. 2 shows the electrical connection of the electromagnetic shielding structure 20. As shown in FIG. 2, the electronic component 9 once goes out of the chassis 13 via the feedthrough capacitor 23, and then returns to the chassis 13 via the feedthrough capacitor 24.
And is connected to the electronic component 12. And
The ground electrode of the feedthrough capacitors 23 and 24 is the chassis 1
3 is electrically connected.

With this configuration, the substrate 2
Only the path passing through the feedthrough capacitors 23 and 24 connects the one main surface 2a and the other main surface 2b. In this case, for example, noise generated in the electronic component 9 is suppressed when passing through the feedthrough capacitor 23, and
Is suppressed when passing through, and hardly reaches the electronic component 12. Therefore, unlike the conventional example, noise does not directly reach from the one main surface 2a of the substrate 2 to the other main surface 2b via the air. As a result, in the electromagnetic shielding structure 20 of the present invention, one main surface 2 of the substrate 2
It is possible to prevent noise from propagating between a and the other main surface 2b.

Although noise coming from outside the chassis 13 may be received by the lead pins 23b and 24b of the feedthrough capacitors 23 and 24, the noise is also suppressed when passing through the feedthrough capacitors 23 and 24, and the electronic components 9 and 12 is unlikely to be noise.

FIG. 3 shows a sectional view of another embodiment of the electromagnetic shielding structure of the present invention. 3, the same or equivalent parts as those in FIG. 1 are denoted by the same reference numerals, and the description thereof will be omitted.

In the electromagnetic shielding structure 30 shown in FIG. 3, a metal flange 31 is integrally formed with the chassis 13 so as to project from the inner surface of the chassis 13 in parallel with the upper surface and the bottom surface (not shown) of the chassis 13. The edge of the substrate 2 is connected to the flange 31 by electrically connecting the ground electrode 6 formed on the other main surface 2 b of the substrate 2 to the flange 31 with solder 11. A through hole 32 is formed in the flange portion 31, and a through capacitor 33 which is a noise removing component is inserted into the through hole 32. The lead pin 33a, which is one terminal of the feedthrough capacitor 33, is connected to the wiring electrode 4 formed on one main surface 2a of the substrate 2, and the lead pin 33b, which is the other terminal of the feedthrough capacitor 33, is connected to the other main surface 2b of the substrate 2. It is connected to the formed wiring electrode 5. In addition,
In FIG. 3, only one end of the substrate 2 is connected to the collar 31, but the substrate 2 is connected to the chassis 13 directly or through the collar 31 around the entire periphery of the substrate 2, and 31 separates the inside of the chassis 13 up and down.

FIG. 4 shows the electrical connection of the electromagnetic shielding structure 30. As shown in FIG. As shown in FIG. 4, the electronic component 9 is connected to the electronic component 12 via the feedthrough capacitor 33. The ground electrode of the feedthrough capacitor 33 is electrically connected to the flange 31.

With this configuration, the substrate 2
The one main surface 2a and the other main surface 2b are connected only to a path passing through the feedthrough capacitor 33. In this case, for example, noise generated in the electronic component 9 is suppressed when passing through the feedthrough capacitor 33 and hardly reaches the electronic component 12. Therefore, unlike the conventional example, noise does not directly reach from the one main surface 2a of the substrate 2 to the other main surface 2b via the air. As a result, in the electromagnetic shielding structure 30 of the present invention, one main surface 2a of the substrate 2 and the other main surface 2b
Can be prevented from propagating noise.

FIG. 5 is a sectional view showing still another embodiment of the electromagnetic shielding structure of the present invention. 5, the same or equivalent parts as those in FIG. 3 are denoted by the same reference numerals, and the description thereof will be omitted.

In the electromagnetic shielding structure 40 shown in FIG. 5, an electric conductor 41 is filled between the inner surface of the through hole 32 of the flange 31 and the ground electrode of the through capacitor 33, and the electric conductor 41 is penetrated. The capacitor 33 is electrically connected to the ground electrode and the flange 31.

With such a configuration, the gap between the through hole 32 of the flange portion 31 and the through capacitor 33 is completely eliminated by the electric conductor 41, and the one main surface 2a side of the substrate 2 and the other main surface 2b The electromagnetic wave can be more effectively shielded from the side of the substrate 2 to prevent the propagation of noise between the one main surface 2a and the other main surface 2b of the substrate 2.

Although the case where the electric conductor 41 is filled in the gap between the feedthrough capacitor 33 and the flange portion 31 in FIG. 3 has been described, the gap between the feedthrough capacitors 23 and 24 and the chassis 13 in FIG. The same operation and effect can be obtained even when the conductor is filled.

In each of the embodiments described above, a feedthrough capacitor is used as a noise removing component. However, another component such as a noise filter may be used. When a noise filter is used, a low-pass filter is generally used, but depending on the type of noise to be prevented from propagating, a band-pass filter, a high-pass filter, and a band-elimination filter (including a notch filter) are used. It does not matter. Further, the shape is not necessarily limited to a cylindrical shape such as a feedthrough capacitor.

FIG. 6 shows still another embodiment of the electromagnetic shielding structure of the present invention. 6, the same or equivalent parts as those in FIG. 3 are denoted by the same reference numerals, and the description thereof will be omitted.

In the electromagnetic shielding structure 50 shown in FIG. 6, both the first circuit including the electronic component 9 and the second circuit including the electronic component 12 are digital circuits, and the through-hole 32 of the flange 31 is provided.
, A photocoupler 51 is inserted as a noise removing component. An input terminal 5 which is one terminal of the photocoupler 51
1a is a lead wire 52 to the wiring electrode 4 formed on the one main surface 2a of the substrate 2, and an output terminal 51b, which is the other terminal of the photocoupler 51, is connected to the wiring electrode 5 formed on the other main surface 2b of the substrate 2. Each of the solders 11 is connected by a lead wire 53.
It is fixed at. Here, the input terminal 51a side of the photocoupler 51 is the photodiode side, the output terminal 51b side is the phototransistor side, and signals are transmitted in one way from the input terminal 51a side to the output terminal 51b side.

In the electromagnetic shielding structure 50 configured as described above, even if high-frequency noise is superimposed on the digital signal output from the electronic component 9, if the level is low, the noise reaches the threshold value of the photocoupler 51. And does not reach the electronic component 12 side. Further, since the electrical pulse of the digital signal is once converted into an optical pulse and transmitted, there is no electrical connection of the signal line between the one main surface 2a side and the other main surface 2b side of the substrate 2. Therefore, the efficiency of noise removal is increased. Thus, one main surface 2a of substrate 2
It is possible to more effectively electromagnetically shield the space between the first main surface 2b and the other main surface 2b, thereby preventing the propagation of noise between the one main surface 2a and the other main surface 2b of the substrate 2.

When a photocoupler is used as a noise removing component, the signal flow is one-way, so if there is a signal flow in the opposite direction, it is necessary to separately provide a photocoupler directed in the reverse direction if necessary. There is.

FIG. 7 is a sectional view showing an embodiment of the electronic device of the present invention. The electronic device 60 shown in FIG. 7 is a device such as a computer that incorporates both a digital circuit portion and an analog power supply circuit portion.

In FIG. 7, an electronic device 60 includes a metal box-shaped chassis 61 and a flange 62 projecting from the inner surface of the chassis 61 in parallel with the upper and lower surfaces of the chassis 61.
And a substrate 63 having one end connected to the collar portion 62 and provided so as to vertically divide the space inside the chassis 61 together with the collar portion 62, and a first circuit formed on one main surface of the substrate 63. , A switching power supply circuit 65 as a second circuit formed on the other main surface of the substrate 63, and a feedthrough capacitor 66 provided through the collar 62. The substrate 63 has a ground electrode layer as an inner layer, and this ground electrode layer is electrically connected to the chassis 61 and the collar portion 62. Electronic device 6
Compared with the electromagnetic shielding structure 30 of FIG. 3, the substrate 63 corresponds to the substrate 2, the digital circuit 64 corresponds to the electronic component 9, the switching power supply circuit 65 corresponds to the electronic component 12, and the feedthrough capacitor 66 corresponds to the feedthrough capacitor 33. I do.

By configuring the electronic device 60 in this manner, when a DC voltage generated by the switching power supply circuit 65 on the other main surface of the substrate 63 is supplied to the digital circuit 64 formed on one main surface of the substrate 63 In addition, noise generated in the switching power supply circuit 65 can be cut by the feedthrough capacitor 66 so that the noise does not reach the digital circuit 64. Thus, in the electronic device 60, the switching power supply circuit 65
Digital circuit 64 without being a source of noise for
Can function normally.

FIG. 7 shows an electronic device such as a computer for preventing the propagation of noise from an analog circuit to a digital circuit. However, the present invention is not limited to this. Alternatively, the present invention is similarly effective in a case where a high-frequency circuit, which is two analog circuits that easily generate noise or is easily affected by noise, such as a tuner, is separated. Although the electronic device using the electromagnetic shielding structure shown in FIG. 3 has been described here, the same operation and effect can be obtained in the electronic device using the electromagnetic shielding structure shown in FIGS. 1, 5, and 6. be able to.

[0038]

According to the electromagnetic shielding structure of the present invention, a substrate having first and second circuits formed on one main surface and the other main surface is provided in the chassis in parallel with the upper and lower surfaces of the chassis. The first and second noise elimination components are inserted by providing through holes above and below the substrate on the side surface of the first noise elimination component, one terminal of the first noise elimination component is connected to the first circuit, and the second noise elimination component is Is connected to the second circuit, and the other terminals of the first and second noise elimination components are connected to each other outside the chassis. Can be prevented from propagating. Also, on the inner surface of the chassis, a flange portion protruding parallel to the top and bottom surfaces of the chassis is connected, the end of the board is connected thereto, a through hole is provided in the collar portion, and a noise removing component is inserted,
A similar effect can be obtained by connecting one terminal to the first circuit and the other terminal to the second circuit. Further, by electrically connecting the ground electrode of the noise removing component to the chassis or the brim portion, the propagation of noise can be effectively prevented. Further, by filling the gap between the noise removing component and the through hole formed in the chassis or the brim portion with the electric conductor, the propagation of the noise can be more effectively prevented.

According to the electronic device of the present invention, by using the above-mentioned electromagnetic shielding structure, a plurality of circuits do not become noise sources for each other, and each circuit always functions normally. Can be done.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of the electromagnetic shielding structure of the present invention.

FIG. 2 is a diagram showing an electrical connection relationship of the electromagnetic shielding structure of FIG.

FIG. 3 is a sectional view showing another embodiment of the electromagnetic shielding structure of the present invention.

4 is a diagram showing an electrical connection relationship of the electromagnetic shielding structure of FIG.

FIG. 5 is a sectional view showing still another embodiment of the electromagnetic shielding structure of the present invention.

FIG. 6 is a sectional view showing still another embodiment of the electromagnetic shielding structure of the present invention.

FIG. 7 is a sectional view showing an embodiment of the electronic device of the present invention.

FIG. 8 is a sectional view showing a conventional electromagnetic shielding structure.

9 is a diagram showing an electrical connection relationship of the electromagnetic shielding structure of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 2 ... Substrate 2a ... One principal surface 2b ... The other principal surface 3 ... Ground electrode layer 9 ... Electronic component (1st circuit) 12 ... Electronic component (2nd circuit) 20, 30, 40 ... Electromagnetic shielding structure 21 ... 1 through hole 22 ... second through hole 23, 24, 33 ... through capacitor (noise removing component) 31 ... flange 32 ... through hole 41 ... electric conductor 60 ... electronic device

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hiroaki Tanaka 2-26-10 Tenjin, Nagaokakyo-shi, Kyoto Inside Murata Manufacturing Co., Ltd.

Claims (7)

[Claims] 1. A chassis having an upper surface, a bottom surface, and a side surface, and a substrate provided between the side surfaces of the chassis inside the chassis. The substrate has first and second main surfaces on one main surface and the other main surface. Wherein first and second through-holes are formed at upper and lower positions with respect to the substrate position on the side surface of the chassis, and first and second noises are formed in the first and second through-holes. A noise removal component is inserted, and one terminal of the first noise reduction component is connected to the first circuit, and one terminal of the second noise reduction component is connected to the second circuit.
Wherein the other terminals of the first and second noise elimination components are connected outside of the chassis. 2. The electromagnetic shielding structure according to claim 1, wherein ground electrodes of said first and second noise removing components are electrically connected to said chassis. 3. The first and second through holes and the first through hole.
And a gap between the first and second noise elimination components is filled with an electric conductor, and the electric conductor is electrically connected to a ground electrode of the first and second noise elimination components and the chassis. The electromagnetic shielding structure according to claim 1, wherein 4. A chassis having an upper surface, a bottom surface, and side surfaces, a flange protruding from an inner surface of the chassis, and a substrate provided between the side surfaces of the chassis inside the chassis. It has first and second circuits on one main surface and the other main surface, and has end portions connected to the collar portion. A through hole is formed in the collar portion, and a noise removing component is inserted into the through hole. An electromagnetic shielding structure wherein one terminal of the noise removing component is connected to the first circuit, and the other terminal of the noise removing component is connected to the second circuit. 5. The electromagnetic shielding structure according to claim 4, wherein a ground electrode of the noise elimination component is electrically connected to the collar. 6. A gap between the through hole and the noise removing component is filled with an electrical conductor, and the electrical conductor is electrically connected to a ground electrode and the collar of the noise removing component. The electromagnetic shielding structure according to claim 4, wherein: 7. An electronic device comprising the electromagnetic shielding structure according to claim 1. Description: