Shielded PCB Conductive Adhesive Extension
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Solution Overview
Problem
Conventional shielded printed wiring boards with large through-hole openings for grounding compromise circuit design flexibility due to reduced space for signal transmission and increased electromagnetic interference (EMI), necessitating improved connection stability and design freedom.
Innovation Solution
A shielded printed wiring board design featuring a conductive adhesive layer with an extension into the through-hole, allowing for enhanced contact area and stability even with small opening areas, combined with a manufacturing method involving thermocompression bonding to ensure effective grounding and minimize void formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a large opening area is used for the through-hole to ensure stable connection between the grounding unit and the shielding film, then connection stability is improved, but the degree of freedom in circuit design is reduced
Solution Approach 1:
The conductive adhesive layer extends in the thickness direction (vertical dimension) into the through-hole, transforming a 2D surface contact problem into a 3D volumetric contact solution. This dimensional transition allows the grounding connection to achieve sufficient contact area without increasing the through-hole opening area in the planar direction, thereby maintaining connection stability while preserving circuit design freedom.
Solution Approach 2:
The conductive adhesive layer is nested within the through-hole, with the adhesive material filling and extending into the hole space. This nesting approach utilizes the vertical space inside the through-hole to create additional contact area between the grounding unit and the shielding film, eliminating the need to enlarge the opening area while ensuring reliable electrical connection.
2Reliability
If the conductive adhesive layer extends toward the inside of the through-hole, then connection stability with small opening areas is improved, but manufacturing complexity increases
Solution Approach 1:
The invention changes the geometric parameters of the conductive adhesive layer, specifically its shape and distribution, by controlling it to extend into the through-hole. This parameter modification is achieved through standard manufacturing processes such as adjusting adhesive application patterns or using fill processes, which do not fundamentally alter the manufacturing workflow but optimize the adhesive's positional parameters to achieve better connection stability.
3Adaptability or versatility
If smaller through-hole openings are used to increase circuit design freedom, then EMI is reduced and design flexibility is improved, but connection stability deteriorates
Solution Approach 1:
By extending the conductive adhesive layer into the thickness direction within the through-hole, the invention compensates for the reduced planar opening area. The vertical extension provides sufficient contact area for stable grounding connection even when the through-hole opening is minimized, allowing small opening sizes that reduce EMI and increase design freedom while maintaining connection reliability.
Solution Approach 2:
The conductive adhesive layer acts as a flexible conductive medium that can adapt its shape and extend into the through-hole space. This flexibility allows the adhesive to maximize contact area with both the grounding unit and the shielding film within the constrained geometry of a small through-hole, ensuring stable electrical connection despite the limited opening area.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The design achieves excellent connection stability and high circuit design freedom by maintaining effective grounding and shielding with smaller through-hole openings, reducing EMI and improving reliability.
Implementation Method 1
a manufacturing method involving thermocompression bonding to ensure effective grounding and minimize void formation
Data Source
AI summary
Provided is a shielded printed wiring board that exhibits excellent connection stability even when having a through-hole with a small opening area, and enables a high degree of freedom in circuit design. The shielded printed wiring board 1 according to the present invention includes a printed wiring board 10, an insulating layer 22, and a conductive adhesive layer 21 disposed between the printed wiring board 10 and the insulating layer 22. The printed wiring board 10 includes a base 11, a circuit pattern 13 disposed on the base, and an insulating protective layer 14 covering the circuit pattern 13. The shielded printed wiring board has a through-hole 23 for external grounding that vertically penetrates the insulating layer 22 and the conductive adhesive layer 21. The conductive adhesive layer 21 has an extension 21a extending toward the inside of the through-hole 23 as compared with the insulating layer 22.