JPH0621681A - Electronic circuit device - Google Patents

Abstract

PURPOSE:To prevent the leakage of electromagnetic noise well by making a flexible substrate for circuit constitution to be enclosed between a pair of flexible substrates wherein a grounded conductor pattern is formed. CONSTITUTION:Electromagnetic noise generated by an electronic circuit which is constituted of an electronic element 4 on a flexible substrate 1 for circuit constitution is screened by a grounded conductor pattern of a pair of shielding flexible substrates 2, 3 holding the substrate 1 therebetween and can be prevented from leaking outside. Since each of the substrates 1, 2, 3 is a flexible substrate, freedom for installation position of an electronic device inside a cage box is improved and just a little occupation volume is required. Furthermore, it is not necessary to use an electronic element wherein what is called EMI countermeasure is considered and compactness and easy manufacturing are possible for an electronic circuit part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic circuit device in which various electronic elements forming an electronic circuit are arranged on a substrate.

[0002]

2. Description of the Related Art Conventionally, various electronic devices have been proposed which are provided with an electronic circuit section composed of a plurality of electronic elements.
In such an electronic device, electromagnetic noise (EMI) generated by the electronic circuit unit is generated.
However, there is a problem in that the c interface leaks to the inside of the housing that constitutes this electronic device or to the outside of the housing. This is because such electromagnetic noise may not only hinder the good operation of this electronic device and other electronic devices, but may also have a considerable effect on the human body.

Therefore, conventionally, the above electronic equipment has been
So-called EMI countermeasures are taken to prevent leakage of the electromagnetic noise. As measures against this EMI, a resistance element is used to reduce the electromagnetic noise together with a signal flowing in the electronic circuit section, a capacitor is used to reduce the electromagnetic noise, and an inductor is used to reduce the electromagnetic noise. There are those which reduce the electromagnetic noise by using an EMI countermeasure filter, and those which seal a portion which becomes an electromagnetic noise generation source in a shield case.

[0004]

By the way, in the electronic equipment as described above, in order to take EMI countermeasures using a resistance element, a capacitor, an inductor, or an EMI countermeasure filter, any portion of the electronic circuit section ( It is necessary to check whether the line) is the source of electromagnetic noise. It is difficult and complicated to find out which line of the electronic circuit section is the source of electromagnetic noise, and it is difficult to take measures against EMI.

Further, in the case where a portion which becomes an electromagnetic noise source is sealed in a shield case, it is necessary to provide a space for accommodating the shield case in the housing of the electronic device, which results in a structure of the electronic device. This leads to an increase in size, a reduction in the degree of freedom of the housing shape, and the like.

Therefore, the present invention has been proposed in view of the above-mentioned circumstances, and does not cause an increase in the size of the configuration of an electronic device and a reduction in the degree of freedom of the housing shape, and does not require complicated work. It is an object of the present invention to provide an electronic circuit device capable of excellently preventing leakage of electromagnetic noise without being accompanied.

[0007]

In order to solve the above-mentioned problems and achieve the above-mentioned object, an electronic circuit device according to the present invention includes a flexible circuit-forming board to which electronic elements forming an electronic circuit are mounted, and A flexible circuit board for shielding, which sandwiches the flexible circuit circuit board from both sides.

Further, according to the present invention, in the above-mentioned electronic circuit device, a grounded conductor pattern is adhered and formed over substantially the entire surface of the shielding flexible substrate.

[0009]

In the electronic circuit device according to the present invention, the electromagnetic noise generated by the electronic circuit formed on the circuit-forming flexible substrate is shielded by the shielding flexible substrate that sandwiches the circuit-forming flexible substrate from both sides. Does not leak outside.

Further, in the above electronic circuit device, when a grounded conductor pattern is formed over substantially the entire surface of the shielding flexible substrate, the electromagnetic noise generated by the electronic circuit is shielded more reliably.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments of the present invention will be described below with reference to the drawings. The electronic circuit device according to the present invention is shown in FIG.
Also, as shown in FIG. 2, it is configured to have a circuit-forming flexible substrate 1 to which a plurality of electronic elements 4 constituting an electronic circuit are attached. Flexible board for circuit configuration 1
Is a base material (base film) made of a highly heat-resistant synthetic resin material such as a polyimide resin (Polyimide).
And a conductor pattern that is adhered and formed in a predetermined shape on the main surface portion of the base material by means of etching or the like.

Each of the electronic elements 4 is a so-called surface-mounting type electronic element, and the terminal portion 4a is soldered to the conductor pattern so as to be placed on the conductor pattern, and the electronic element 4 and the conductor pattern are connected together. It works to form a predetermined electronic circuit.

The surface portion of the conductor pattern is covered with an insulating layer (cover film) except the portion to which the terminal portion 4a of each electronic element 4 is soldered. This insulating layer is formed of a synthetic resin material or the like.

The circuit-forming flexible substrate 1 has a lead-out portion 1a. The lead-out portion 1a is a narrow portion in which a conductor pattern for connecting the electronic circuit to another electronic circuit or an electronic device is formed, and a main body to which the electronic elements 4 of the flexible substrate 1 are attached. It is formed in a peninsular shape protruding from the portion.

In this electronic circuit device, the circuit-forming flexible substrate 1 is sandwiched and sealed from both sides by the first and second shield flexible substrates 2 and 3. As shown in FIG. 3, each of the shield flexible substrates 2 and 3 has a base material made of a polyimide resin, a ground conductor pattern 5 adhered to one main surface of the base material, and the ground conductor. The insulating layer 6 is further formed on the pattern 5 by deposition. The ground conductor pattern 5 is formed of copper foil or the like in a planar shape so as to cover substantially the entire surface of each of the shield flexible substrates 2 and 3 and is grounded to the ground potential.

A solder-plated portion 7 is provided around the ground conductor pattern 5. The respective flexible boards 2 and 3 for shielding are arranged such that the main surface portions on the side where the ground conductor pattern 5 is formed face each other.
The flexible board 1 for circuit configuration is sandwiched. The flexible substrates 2 and 3 for shielding are shown in FIG.
As shown by the middle arrow D, the solder-plated portions 7, 7 are welded to each other and joined. The ground conductor patterns 5 and 5 of the shield flexible substrates 2 and 3 are electrically connected to each other through the solder-plated portions 7 and 7 to form a bag-shaped shield body.

The lead-out portion 1a is drawn outward from the space between the shield flexible substrates 2 and 3.

In the electronic circuit device according to the present invention constructed as described above, the electromagnetic noise generated by the electronic circuit constituted by the electronic elements 4 is caused by the ground conductor pattern of the shielding flexible boards 2, 3. It is shielded by 5, 5 and does not leak to the outside. However, in the derivation unit 1a, as indicated by an arrow A in FIG.
Although a slight leakage of the electromagnetic noise is expected, this electromagnetic noise can be easily blocked because the leakage portion of the electromagnetic noise is limited to a narrow range.

In this electronic circuit device, since each of the substrates 1, 2 and 3 is a flexible substrate, the electronic circuit portion formed on the circuit-forming flexible substrate 1 is:
The degree of freedom in the installation position of the electronic device in the housing is high, and the occupied volume is small. Further, in this electronic circuit device, since the entire electronic circuit portion is shielded, it is not necessary to use an electronic element for so-called EMI measures, and the electronic circuit portion can be downsized and manufactured. Has been facilitated.

The ground conductor pattern 5 may be formed in a mesh shape or a grid shape so as to cover substantially the entire surface of each of the shield flexible substrates 2 and 3.

As shown in FIG. 4, the electronic circuit device according to the present invention may be constructed by providing a pair of lead-out portions 1a and 1b on the flexible board 1 for circuit construction. These lead-out portions 1a and 1b are drawn out to the outside from between the above-mentioned shield flexible substrates 2 and 3. In this case, as shown by arrows B and C in FIG. 4, one of the derivation units 1a and 1b is used for inputting a signal to the electronic circuit unit and the other is a signal output from the electronic circuit unit. Be used for.

Further, the electronic circuit device according to the present invention is not limited to the structure having the first and second shield flexible substrates 2 and 3 as shown in the above-mentioned embodiment, and as shown in FIG. One flexible board for shield 2
May be bent, and the flexible circuit board 1 for shielding may be wrapped with the flexible circuit board 2 for shielding. This flexible board 2 for shield is
First shield flexible substrate 2 in the above-described embodiment
Similarly to the above, it has a base material, a ground conductor pattern 5, an insulating bath 6, and a solder plating portion 7. The shield flexible substrate 2 has the ground conductor pattern 5 described above.
Is substantially half-folded from the center so that the inner side of the flexible substrate 1 for circuit construction is wrapped. The ground conductor pattern 5 constitutes a bag-shaped shield body by welding the portions of the solder-plated portion 7 which face each other, and the flexible board 1 for circuit configuration.
Shields electromagnetic noise generated by the electronic circuit unit configured above.

In each of the above-described embodiments, the conductor pattern and the terminal portion 4a on the circuit-forming flexible substrate 1 are covered with the insulating layer 8, and the ground conductor pattern 5 is covered with the insulating layer 6. By being covered, the conductor pattern, the terminal portion 4a, and the ground conductor pattern 5 are prevented from being electrically short-circuited with each other.

[0024]

As described above, the electronic circuit device according to the present invention is used for shielding electromagnetic noise generated by an electronic circuit formed on a circuit-forming flexible substrate from both sides of the circuit-forming flexible substrate. It can be shielded by the flexible substrate and prevented from leaking to the outside.

Further, in the above electronic circuit device, when the grounded conductor pattern is formed over substantially the entire surface of the shielding flexible substrate, the electromagnetic noise generated by the electronic circuit can be more surely shielded. it can.

In this electronic circuit device, since each of the substrates is a flexible substrate, it can be formed in a small size and can be formed in any shape.

Further, this electronic circuit device does not require an electronic element for so-called EMI countermeasures, and it is not necessary to check which part of the electronic circuit is the electromagnetic noise source.

That is, according to the present invention, the leakage of electromagnetic noise can be satisfactorily prevented without causing an increase in the size of the structure of electronic equipment, a reduction in the degree of freedom of the housing shape, and a complicated operation. It is possible to provide an electronic circuit device configured as described above.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing a configuration of an electronic circuit device according to the present invention.

FIG. 2 is a plan view showing a configuration of the electronic circuit device.

FIG. 3 is an enlarged vertical sectional view of an essential part showing the configuration of the essential part of the electronic circuit device.

FIG. 4 is a plan view showing another example of the configuration of the electronic circuit device.

FIG. 5 is an enlarged vertical sectional view showing still another example of the configuration of the electronic circuit device.

[Explanation of symbols]

1 ... Flexible substrate for circuit configuration 2 ... ...... First shield flexible substrate 3 ・ ・ ・ ・ ・ ・ ・ ・ Second shield flexible substrate 4 ・ ・ ・ ・ ・.... Electronic element

Claims (2)

[Claims] 1. An electronic circuit device comprising: a circuit-forming flexible substrate to which electronic elements constituting an electronic circuit are attached; and a shielding flexible substrate sandwiching the circuit-forming flexible substrate from both sides. 2. The electronic circuit device according to claim 1, wherein a grounded conductor pattern is adhered and formed on substantially the entire surface of the shield flexible substrate.