JPH0745992Y2 - Grounding structure between electronic parts and shield case - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a grounding structure for an electronic component mounted on a printed circuit board and a shield case for covering the electronic component.

(Prior Art) For example, in a printed circuit board for a high-frequency circuit such as an RF signal oscillator, a space including electronic parts such as a filter and a capacitor that constitutes the oscillator is shielded to enhance the shielding effect of the oscillator. Often covered by a case.

That is, FIGS. 3 (a) and 3 (b) are views showing a state in which an electronic component mounted on a printed circuit board is covered with a metal shield case, and a chip electronic component such as a filter 2 and a capacitor 3 on the substrate 1. After being soldered by reflow, the lower edge 4a of the shield case 4 and the earth pattern portion on the periphery of the substrate 1 are fixed by solder 5. Further, in order to sufficiently ground the electronic components such as the filter 2 and the like, measures are taken such that the package of the electronic component and the inner wall of the shield case 4 are brought into close contact with each other, or a metal plate or the like is inserted to electrically connect them. Was there. The board 1 is mounted on the motherboard by performing reflow connection with the ground pattern, lead terminals, etc. formed on the bottom surface of the board 1 positioned and mounted on the wiring pattern on the motherboard.

However, when the substrate 1 provided with the electronic components 2 and 3 and the shield case 4 is positioned on a mother board (not shown) and reflow connection is performed, the solder 5 that connects the peripheral edge of the substrate and the lower edge of the shield case by heating during reflow is formed. There was a case where the resin melted and caused a positional shift, the connection state between the inner wall of the shield case and the package of the electronic component deteriorated, and a ground failure occurred. If the package of the filter 2 is not sufficiently grounded, it becomes impossible to secure a desired amount of attenuation, resulting in deterioration of the characteristics of the entire circuit.

(Object of the Invention) The present invention has been made to eliminate the drawbacks of the conventional grounding structure of an electronic component and a shield case. The package of the electronic component mounted on the substrate and the grounding of the shield case covering the package are provided. It is an object of the present invention to provide a grounding structure between an electronic component and a shield case that can ensure the above.

(Summary of the Invention) In order to achieve the above object, the grounding structure of an electronic component and a shield case of the present invention has a structure in which an electronic component mounted on a printed circuit board is covered by a metal shield case. When soldering, the package of the electronic component and the inner wall of the shield case are connected by a conductive adhesive.

(Embodiment) Hereinafter, a grounding structure of an electronic component and a shield case of the present invention will be described in detail based on a preferred embodiment shown in the accompanying drawings.

FIG. 1 is a structural explanatory view of a grounding structure of an embodiment of the present invention, in which chip electronic parts such as a filter 2 and a capacitor 3 are solder-grounded by reflow on a substrate 1 and a lower edge 4a of a shield case 4 is formed. The ground pattern portion on the periphery of the substrate 1 is fixed by the solder 5.

The size of the shield case 4 in the height direction is set so that a predetermined minute gap is formed between the package of the electronic component 2 and the inner wall of the shield case 4, and conductive adhesion is applied to the upper surface of the package or the ceiling of the inner wall of the shield case. The shield case 4 is covered on the component with the agent 6 applied, and then the lower peripheral edge of the shield case and the peripheral edge of the substrate are fixed with solder 5.

If the shield case 4 and the board are solder-connected after the electronic component package and the inner wall of the shield case 4 are bonded and fixed in this way, even if the solder 5 is melted when the board 1 is reflow-connected to a motherboard (not shown). Therefore, the shield case 4 is not displaced and the connection state with the electronic component package is not deteriorated.

Next, FIG. 2 is an example in which the connection structure of the present invention is applied to another type of electronic component, and an electronic component 7 having a metal package 8 and leads 9 is laid down and mounted on a substrate 1. In this electronic component 7, the lead 9 and the proper place of the package are soldered to the pattern 11 on the substrate 1 and at the same time,
An intermediate portion of the package is fixed on the substrate 1 with a fixing adhesive 12, and the package and the shield case 4 are bonded and fixed with a conductive adhesive 6.

In this embodiment as well, since the electronic component package 8 and the inner wall of the shield case 4 are adhesively fixed, even if the solder 5 melts when the board 1 is reflow-connected to the motherboard, the displacement of the shield case 4 is caused. Therefore, the connection state with the electronic component package does not deteriorate.

Therefore, it is possible to prevent the characteristic deterioration of the electronic component due to the insufficient grounding of the package.

(Effect of the Invention) As described above, according to the present invention, when the electronic components mounted on the printed circuit board are covered with the metal shield case, the electronic component package and the inner wall of the shield case are bonded and fixed with a conductive adhesive. Therefore, even if the solder connection part between the board and the shield case is displaced due to heat when the board is reflow-connected to the motherboard, the connection between the electronic component package and the shield case will deteriorate. There is no.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view showing a connection structure of one embodiment of the present invention,
FIG. 2 is a vertical sectional view showing a connection structure of another embodiment of the present invention, and FIGS. 3 (a) and 3 (b) are explanatory views of a conventional connection structure. 1 ... Substrate, 2, 3, 7 ... Electronic component 4 ... Shield case, 5 ... Solder 6 ... Conductive adhesive

Claims (1)

[Scope of utility model registration request] 1. A ground structure in which an electronic component mounted on a printed circuit board is covered with a metal shield case to fix the substrate to the shield case by soldering, and a package of the electronic component is connected to an inner wall of the shield case. The ground structure for an electronic component and a shield case, wherein the package and the inner wall of the shield case are bonded and fixed with a conductive adhesive.