JPH06283884A - Shielded board and its shield process - Google Patents

Abstract

PURPOSE:To provide a shielded board and its shield process whose shield is made easy and shield effect is improved. CONSTITUTION:After a circuit pattern 4 is formed in a circuit board 2 and a grounding pattern 8 is formed in a position wherein the circuit pattern is enclosed, positioning frames 12A, 12B are formed along the grounding pattern. A shield member (shield case 16) is positioned by the positioning frame, and the shield member and the grounding pattern are fixed by a sealing member (conductive adhesive 18) and electrically connected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shield substrate provided with a shield member for shielding noise and a method for treating the shield substrate.

[0002]

2. Description of the Related Art Generally, when forming a power supply device or the like by using a thick film circuit device, a shield measure is indispensable as a noise measure for an adjacent circuit. For example, the power supply is DC
Although a DC converter is used, such a circuit generates high frequency noise, and therefore a sufficient shield treatment is required.

Generally, as a measure for shielding a circuit device, a method of housing a circuit board in a metal case is generally used. The circuit board is housed in the metal case by fixing the circuit board in the metal case having a hermetically sealed structure and pulling out its leads in a non-contact state with the metal case. Naturally, it is necessary to take insulation measures between the metal case and the leads, and conventionally, methods such as air insulation and interposition of an insulating material have been taken.

In the case of air insulation, there is a method of forming a through hole in a metal case and installing a lead at a position corresponding to the hole. Such a method requires positional accuracy and absorbs positional errors, so that it is necessary to increase the size of the through hole. However, when the through hole is made large, the leakage of noise from this through hole becomes a problem. Also,
The interposition of the insulator complicates the treatment, and after the treatment of the insulator, it becomes difficult to open and close the metal case, and in order to enable the opening and closing, a device for that is required.

[0005]

From such a background,
By installing a shield member on the surface of the circuit board,
It has been proposed to cover the entire circuit pattern or selectively with a shield member. In the shield of such a shield member, the shield effect is impaired depending on the connection with the ground pattern to the circuit pattern, its mounting structure, etc., and the mounting accuracy affects the yield in mass production, and the manufacturing cost deteriorates.

Therefore, it is an object of the present invention to provide a shield substrate and a method of treating the shield substrate, which facilitates the shield treatment and enhances the shield effect.

[0007]

As shown in FIG. 2, a shield substrate of the present invention surrounds a circuit pattern (4) of a circuit substrate (2) to be shielded by a shield member (shield case 16). The ground pattern (8) formed and the positioning frame (12A, 12B) of the shield member formed along the ground pattern are provided, and the shield member is fixed by the fixing member (conductive adhesive 18). It is characterized in that it is connected to a ground pattern and the circuit pattern of the circuit board is covered with the shield member.

Further, in the method for treating a shield substrate of the present invention, as shown in FIGS. 2 and 3, a circuit pattern (4) is formed on the circuit substrate (2), and the circuit pattern (4) is formed at a position surrounding the circuit pattern. After forming the ground pattern (8), the positioning frames (12A, 1
2B) is formed, the shield member (shield case 16) is positioned by this positioning frame, and the shield member and the ground pattern are fixed by a fixing member (conductive adhesive 18) and electrically connected. Is characterized by.

[0009]

In this shield board, the ground pattern is formed at a position surrounding the circuit pattern of the circuit board, the positioning frame of the shield member is formed, and the shield member is installed on the basis of this positioning frame and the fixing member is provided. It is fixed and electrically connected to the ground pattern. In such a shield structure, a desired circuit pattern can be wholly or partially surrounded by a ground pattern, and the shield member can shield the circuit pattern.

The ground pattern surrounding the circuit pattern and the shield member for concealing the circuit pattern are electrically connected, and the shield member and the ground pattern reliably shield the circuit pattern entirely or partially. It is possible to obtain a highly reliable shield effect. Moreover, since the positioning frame is installed to position the shield member, the mounting position is highly accurate and the shield reliability can be improved.

Further, in this shield substrate processing method,
Corresponding to the formation of the circuit pattern, a ground pattern is formed at a position surrounding the circuit pattern, and a positioning frame is formed along the ground pattern. A fixing member is installed on the positioning frame to fix the shield member. Such a process is at the same level as the circuit pattern formation, and the circuit pattern on the circuit board can be easily shielded entirely or partially, and a highly reliable shield can be obtained by a uniform process. Can be realized. The positioning frame facilitates positioning of the shield member, enhances the positional accuracy of the shield member, and prevents the sticking member having fluidity from protruding to prevent the influence on the circuit device. It also contributes to improving the quality.

[0012]

The present invention will be described in detail below with reference to the embodiments shown in the drawings.

FIGS. 1A, 1B and 2 show an embodiment of the shield substrate and its processing method of the present invention, and FIG. 2 shows a part of the shield substrate shown in FIG. .
An insulating substrate such as a ceramic substrate is used as the circuit board 2, and an arbitrary circuit pattern 4 is formed on the surface thereof. A plurality of circuit components 6 such as capacitors, resistors and transistors are mounted on the circuit pattern 4.

The circuit pattern 4 is formed on the circuit board 2.
A ground pattern 8 is formed at a position surrounding the. The ground pattern 8 is formed by printing Ag-based conductive paste or the like and firing the same as the conductive layer forming the circuit pattern 4. In this embodiment, a plurality of conductor layers 10 for connecting lead terminals are formed on the edge of the circuit board 2.

Positioning frames 12A, 12B are formed on the surface of the circuit board 2 so as to surround the ground pattern 8 and indicate the mounting positions of the shield members. Each positioning frame 12A, 12B is formed in an annular shape by printing an insulator, for example, an insulating paste, and each positioning frame 12A, 12B
A constant space 14 is formed between the 12B. This space 14 is a shield case 16 as a shield member.
And a space for holding the conductive adhesive 18 as a fixing member for fixing.

The shield case 16 is formed by molding a metal plate having good conductivity, and its opening area corresponds to the annular portion formed by the space 14 between the positioning frames 12A and 12B. The shield case 16 is fixed inside the space 14, that is, by the conductive adhesive 18 filled inside the shield case 16, and is electrically connected to the ground pattern 8. In this case, the positioning frame 1
2A and 12B have a volume within the space 14 to prevent the conductive adhesive 18 from squeezing out to the outside and to retain a surplus.

Next, FIG. 3 shows positioning frames 12A and 12B.
7 shows the treatment of the conductive adhesive 18 with respect to. The positioning frames 12A and 12B are formed by printing and firing a thick film dielectric paste. In this case, the positioning frame 12
In order to set the height of A and 12B, at least 40 μm is obtained by printing the thick film dielectric paste two or more times.
Set to m or more. Then, the positioning frames 12A and 12B
The ground pattern 8 is formed in the space 14 between the ground patterns 8 and the ground pattern on the circuit pattern 4 side is integrally and electrically connected to the ground patterns 8 in the space 14 between the positioning frames 12A and 12B. . As a result, the ground point of the circuit pattern 4, the ground pattern 8 and the shield case 16 are set to the same potential, and a reliable shield effect is obtained.

Then, as a means for supplying the conductive adhesive 18 into the space 14 between the positioning frames 12A and 12B, for example, a dispenser 20 is used to pour the conductive adhesive 18 and then the shield case 16 is installed and pushed. The shield case 16 is fixed and electrically connected to the ground pattern 8 by being dried and cured by.

Next, FIGS. 4 and 5 show another embodiment of the shield substrate and the processing method thereof according to the present invention.

In the above embodiment, the conductive adhesive 18 is filled inside the shield case 16. However, as shown in FIG. 4, the conductive adhesive 1 is placed outside the shield case 16.
8 may be filled.

Further, in the above embodiment, the positioning frame 12
Although A and 12B are formed at positions surrounding the circuit pattern 4 and the ground pattern 8 is set to be positioned within the interval 14, the positioning frame is placed on the ground pattern 8 as shown in FIG. 5, for example. 12B may be formed, and although not shown, the positioning frames 12A and 12B may be formed on the ground pattern 8 having a wide area.

In the embodiment, a conductive adhesive is used as the fixing member, but if the electrical connection is made with solder or the like,
An insulating adhesive may be used. Alternatively, solder may be used as the fixing member.

[0023]

As described above, according to the shield substrate of the present invention, the circuit pattern on the circuit substrate can be wholly or partially shielded, and the processing can be simplified. In addition, a highly reliable shield effect can be realized.

Further, according to the method for processing a shield substrate of the present invention, the positioning accuracy of the shield member to be installed on the circuit board can be improved, the processing can be simplified and a highly reliable shield effect can be realized. The sticking member for fixing and electrically connecting the shield member can be prevented from protruding, and the appearance quality of the shield substrate can be improved.

[Brief description of drawings]

FIG. 1 shows an embodiment of a shield substrate of the present invention,
(A) is the top view, (B) is the BB sectional view taken on the line of (A).

FIG. 2 is a cross-sectional view showing a part of the shield substrate shown in FIG. 1 and a processing method thereof.

FIG. 3 is a perspective view showing an embodiment of a method for treating the shield substrate shown in FIG.

FIG. 4 is a cross-sectional view showing another embodiment of the shield substrate and the processing method thereof according to the present invention.

FIG. 5 is a cross-sectional view showing another embodiment of the shield substrate and the processing method thereof according to the present invention.

[Explanation of symbols]

 2 circuit board 4 circuit pattern 8 ground pattern 12A, 12B positioning frame 16 shield case (shield member) 18 conductive adhesive (fixing member)

Claims (2)

[Claims] 1. A fixing member, comprising: a ground pattern formed surrounding a circuit pattern of a circuit board to be shielded by a shield member; and a positioning frame for the shield member formed along the ground pattern. The shield board is characterized in that the shield member is connected to the ground pattern and the circuit pattern of the circuit board is covered with the shield member. 2. A circuit pattern is formed on a circuit board, and a ground pattern is formed at a position surrounding the circuit pattern, and then a positioning frame is formed along the ground pattern, and the shield member is positioned by the positioning frame. Then, the shield member and the ground pattern are fixed by a fixing member and electrically connected to each other, and the shield substrate processing method.