JPH08148877A - Shield device for electronic equipment - Google Patents

Abstract

PURPOSE: To shield a circuit, which generates electromagnetic waves, using a printed board only without using an aperture shield member or the like for preventing the electromagnetic waves from leaking through an aperture bored in a shield member. CONSTITUTION: A shield member 1 comprising a circuit, which generates electromagnetic waves, is formed into a constitution, wherein a contact plug 4A or a wire 5A can be inserted in an aperture bored in the member 1, a shield pattern (a grounding pattern) 2A is provided on the surface on at least one side of the surface of a printed board 2, the side of the pattern 2a is made to cover on the aperture 3 in such a way as to cover the aperture 3 to fix the side of the pattern 2A on the shielding member 1, the plug 4A or the wire 5A is made to connect with the board 2 made to face the aperture 3 and the board 2 is made to connect with an external circuit.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shield device for electronic equipment, and more particularly to a shield device for electronic equipment capable of lowering radiation and conduction noise due to electromagnetic interference.

[0002]

2. Description of the Related Art Conventionally, various regulations have been implemented with respect to electromagnetic interference (hereinafter referred to as EMI) from various electronic devices. For example, M
In a disc recording / reproducing apparatus in which a radio is mounted on a D (mini Disc) or a CD (compact Disc), an EMI is given to a tuner of the radio from a circuit block that drives an MD,
It is the cause of noise generation. These EMI generally have radiation noise transmitted through the space from the MD circuit block of the generation source, conduction noise transmitted through the power supply line, and the like, and various shielding measures (hereinafter referred to as shield) are taken.

For these countermeasures, an EMI filter is used, or in the case of a connector or the like, the cable or wire side or the panel side is dropped to the ground potential to enhance the shield effect.
The circuit block that generates MI is shielded by a shield plate or the circuit block is stored in a shield case.

FIG. 8 is a side sectional view showing a printed circuit board of a circuit block system housed in such a shield case to eliminate the influence of electromagnetic waves.

In the figure, reference numeral 1 denotes a metallic shielding member made of a box-shaped copper plate or the like, and shows a printed circuit board 2 on which a circuit block for generating EMI is mounted. The printed circuit board 2 has a stat 8 interposed therebetween. And is fixed to the shielding member 1.

Reference numeral 4 indicates a connector (connector) for leading out or introducing a connection wire or a power supply wire to the outside. These wire cables, FFC (Flex)
ibleFlat Cable) or FPC (Flexible Printed Circ)
A uit) (hereinafter referred to as a flat wire) 5 is configured to be led in and out through an opening 3 formed in the shielding member 1.

However, in the circuit block which generates a strong electromagnetic wave, the opening 3 and the flat wire 5 formed in the shielding member 1
Since the electromagnetic wave leaks to the outside from the gap, the opening shield member 1A that covers the opening 3 is attached near the opening 3. Further, at a higher frequency, it is arranged to be led in and out through a hermetic shield (penetrating capacitor) or the like.

[0008]

As described above, in the conventional structure, the opening shield member 1A must be added in addition to the shield member 1, and in the case of using a feedthrough type capacitor or the like, the number of flat wires is the same. The feedthrough capacitor is required, and not only the number of parts is increased, but also much labor is required, which causes a problem that the cost is increased.

The present invention is to provide a shielding device for electronic equipment, which is designed to solve the above problems, and an object thereof is to provide an opening shield member by simply forming an opening 3 in the shielding member 1. It is intended to obtain a shielding device for an electronic device that effectively shields the printed circuit board 2 of a circuit block that generates EMI without adding 1A.

[0010]

As shown in FIG. 1, a shielding device for electronic equipment according to the present invention is provided with a shielding member 1 for shielding electromagnetic interference, and this shielding member 1.
The opening 3 into which the connector 4A or the wire 5A pierced on the side can be inserted
And a printed board 2 having a circuit to be shielded by the shield member 1 in the shield member 5 and a shield pattern printed to shield leakage of electromagnetic waves from the circuit. The printed circuit board 2 is mounted in the opening 3 so that the shielding pattern side faces each other, and is connected to the circuit to be shielded via the connector 4A or the wire 5A provided in the opening 3.

[0011]

According to the shielding device for electronic equipment of the present invention, the shielding pattern 2A for grounding is formed on the back surface side of the printed circuit board 2 on which the circuit block for generating EMI is mounted, and the shielding pattern 1A is formed on the shielding pattern 2A side. Since it is arranged so as to face the opening 3 and is introduced through the connector 4A or the wire 5A, it is possible to obtain an opening shield member 1A or the like which does not particularly need to be shielded in the opening 3. To be

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a shielding device for electronic equipment according to the present invention will be described below in detail with reference to FIGS. FIG. 1 is a perspective view showing the shield case of the present embodiment by cutting off a part of the overall configuration, FIG. 2A is a perspective view of the printed board viewed from the direction B (back side) of FIG. Is in the C direction of Fig. 1 (front side)
FIG. 3 is a perspective view of the printed board viewed further, and FIG. 3 is a cross-sectional view taken along the line AA of FIG.

In FIG. 1, the shielding member 1 is formed in a box shape of a substantially rectangular parallelepiped shape and is formed of a brass plate, a copper plate, or the like. For example, a rectangular plug into which the plug 4A or the flat wire 5A can be inserted on the upper surface of the shielding member 1. A shaped opening 3 is bored.

One side of the shield pattern 2 is provided with a printed circuit board 2 which is double-sided printed from the inside of the shield member 1 in the opening 3.
It is arranged via a screw 15 (see FIG. 3) or the like so that the side on which A is formed contacts.

An example of a pattern viewed from both sides of the printed board 2 is shown in FIGS. 2A and 2B. FIG. 2A shows the back side of the printed circuit board 2, and the portion indicated by the alternate long and short dash line corresponds to the opening 3. Other than the region 15 in which the through hole 7 connecting the contact plugs 4A and 4B is formed. All have a shielding pattern 2A of copper foil for grounding.

The connector 4A may be a surface mount type FFC or FPC connector or a DIP (dual in line package) type connector, and is shown in a side sectional view near the opening 3 in FIG. Similarly, the shielding pattern 2A is brought into contact with the shielding member 1 for shielding and screwed by the screw 15,
Is fastened to the chassis 13 with screws 16. The flat wire 5A led out from the connector 4A is connected to the circuit block 14 and the like that receives the EMI fixed to the chassis 13 by the stat 8.

On the front side of the printed board 2, a wiring pattern 2B for a normal circuit is formed of copper foil, a through hole 7 and various electric parts 6 are attached, and a plurality of contact holes 4A are arranged in the through hole region 15. The through hole 7 is connected to the contact plug 4B which is penetrated to the front side of the printed board and attached to the front side, and the power supply voltage and various kinds of electric power are supplied to each electronic component on the wiring pattern 2B through the flat wire 5B connected to the contact plug 4B. Supplies or derives signals.

According to the shielding device for an electronic device having the above-described structure, the shielding pattern 2A is only formed when the wiring pattern 2B is formed on the back surface side of the printed board 2, and most of the opening 3 except the through hole region 15. And shield pattern 2
Since it is shielded by A and grounded through the shield member 1 and the chassis 13, a large shield effect can be achieved.

In the structure shown in FIG. 4, an EMI filter 10 is interposed on the wiring pattern 2B side on the line of the through hole 7 connecting the connecting plugs 4A and 4B in order to block the conduction noise. With such a structure, spatial noise and conduction noise can be prevented. The EMI filter may be a capacitor or an inductance coil alone, but a π-type or T-type LPF (low-pass filter) or the like may be used.

FIGS. 5 and 6 show the contact plugs 4A and 4B in order to prevent the electromagnetic waves propagating through the space having the structure described with reference to FIGS. 1 and 2 from leaking from the through hole region 15. The position of the through hole 7 connecting the two is brought to a position separated from the opening 3 of the shielding member 1, and the shielding pattern 2A for grounding on the back surface side of the printed board 2 is formed as shown in FIGS. 5 and 6. The shielding pattern 2A is formed on all except the portion. However, in this case, the shielding member 1
It is necessary to interpose the insulator 11 made of an insulating sheet or the like between the shield pattern 2A and the shield member 1 in order to prevent an electrical short circuit between the shield pattern 2A and the shield member 1A. With this configuration, spatial noise is completely shielded.

FIG. 7 is a side sectional view showing still another structure of the present invention. When the contact plug 4A cannot be arranged in the opening 3 for some reason, the rear surface of the printed board 2 is entirely shielded. Flat wire 5 such as FFC for forming pattern 2A
A is passed between the shielding member 1 and the shielding pattern 2A of the printed circuit board 2 and is connected to the wiring pattern 2B side of the printed circuit board 2 with the plugs 4A and 4A.
Even if the B and EMI filters 10 and the like are provided, connection with an external circuit can be performed without impairing the shielding effect.

In each of the above-mentioned embodiments, one printed circuit board having a pattern on the front and back sides has been described, but it is also applicable to a multilayer printed circuit board configured to connect the front and back sides with through holes. Although the circuit board that generates EMI has been described, a dedicated printed board having a shielding pattern may be provided in the opening and various electric components may be attached to the printed board. Further, in the structure in which the insulating layer 12 such as a resist is applied on the shielding pattern 2A, it is obvious that the screw 15 and the shielding pattern 2A may be connected to each other by a ground wire or the like to maintain the ground potential.

[0023]

Since the present invention is configured as described above, the leakage of electromagnetic waves can be prevented only by covering the opening of the shielding member 1 with the shielding pattern 2A of the printed board 2, so that the opening shielding member and the feedthrough capacitor can be prevented. It is possible to reduce the number of parts and improve workability without requiring the above. Also, the design,
Since conventional parts can be reused in manufacturing, cost and delivery can be shortened, and when patterning as a dedicated printed board, other electric parts can be arranged on the other surface, which is space-friendly for electronic equipment. A shielding device is obtained.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of a shielding device for an electronic device of the present invention.

FIG. 2 is a perspective view of a printed circuit board used in the electronic device shielding apparatus of the present invention, and FIG. 2A is a perspective view seen from the direction B of FIG. 1;
FIG. 2B is a perspective view seen from the direction C in FIG. 1.

FIG. 3 is a side sectional view taken along the line AA of FIG.

FIG. 4 is another side cross-sectional view of the electronic apparatus shielding device of the present invention.

FIG. 5 is a side sectional view (I) showing still another embodiment of the electronic apparatus shielding device of the present invention.

FIG. 6 is a perspective view of the printed board viewed from the lower side of FIG.

FIG. 7 is a side sectional view (II) showing still another embodiment of the shielding apparatus for electronic equipment of the present invention.

FIG. 8 is a configuration diagram of a conventional shielding device for an electronic device.

[Explanation of symbols]

 1 shield member 2 printed board 2A shield pattern 2B wiring pattern 4, 4A, 4B plug 5,5A, 5B flat wire

Claims (1)

[Claims] 1. A shield member provided to shield electromagnetic interference, an opening into which a plug or wire rod formed in the shield member can be inserted, and a circuit to be shielded by the shield member in the shield member. And a printed circuit board on which a shielding pattern for shielding the leakage of electromagnetic waves from the circuit is printed, and is mounted so that the shielding pattern side of the printed circuit board faces the opening formed in the shielding member. A shield device for electronic equipment, wherein the shield device is connected to the circuit to be shielded through a plug or a wire rod provided in the opening.