Shield Member Waveguide Opening for PCB Noise Leakage
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Solution Overview
Problem
In electronic apparatuses with printed boards, wiring connections often prevent complete coverage by shield members, leading to noise leakage through openings, which compromise noise shielding effectiveness.
Innovation Solution
An electroconductive shield member with a tubular opening that extends along the wiring path, electrically connected to a conductor, forms a waveguide with the printed board's ground layer to prevent noise propagation, allowing wiring to pass through while shielding specific frequency electromagnetic waves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a shield member is provided to cover a circuit element generating noise, then noise shielding effectiveness is improved, but wiring connections require opening parts that become routes for noise leakage
Solution Approach 1:
The patent applies the nesting principle by placing the wiring inside the opening of the shield member, where the wiring is nested within the protective structure rather than requiring the shield to be broken or separated. The opening is positioned and sized to accommodate the wiring while maintaining the shield's continuity for noise blocking, effectively nesting the wiring within the shield member's protective envelope.
Solution Approach 2:
The patent resolves the contradiction by transitioning from a two-dimensional planar shield to a three-dimensional structure with a controlled opening. The opening extends in the thickness direction of the shield member, creating a vertical dimension that allows wiring passage while the opening's dimensions in other directions are controlled to prevent noise leakage. This dimensional approach allows the wiring to pass through without compromising the shield's noise-blocking capability.
2Ease of operation
If an opening part is provided in the shield member for wiring passage, then wiring connectivity is improved, but noise leakage through the opening increases
Solution Approach 1:
The patent applies parameter changes by carefully controlling the opening's dimensions, position, and orientation. The opening is designed with specific width and length parameters that are sufficient for wiring passage but small enough to block noise frequencies. The opening is positioned at the outer edge of the shield area where it minimizes interference with the shield's overall noise-blocking performance while maintaining wiring connectivity.
3Object-affected harmful factors
If the shield member completely covers the circuit element, then noise shielding is improved, but wiring cannot make contact with circuit elements on the front surface
Solution Approach 1:
The patent applies nesting by allowing the wiring to pass through the opening and make contact with circuit elements on the front surface, while the opening itself is nested within the shield member's protective structure. This enables wiring accessibility without compromising the shield's coverage, as the opening is an integrated part of the shield rather than a separate access point.
Solution Approach 2:
The patent resolves the accessibility issue by utilizing the thickness direction of the shield member for the opening. Instead of creating a lateral opening that would compromise shielding, the opening extends vertically through the shield's thickness, allowing wiring to access front surface circuit elements while maintaining the shield's lateral continuity for noise blocking.
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
Effectively restrains noise leakage by creating a waveguide that blocks unwanted electromagnetic frequencies, ensuring efficient noise shielding even with wiring connections on the printed board surface.
Implementation Method 1
the opening and the conductor form a waveguide surrounding the wiring
Data Source
AI summary
An electronic apparatus includes a printed board and an electroconductive shield member disposed such as to cover a shield area which is a part of a front surface of the printed board. A wiring connecting an inside and an outside of the shield area is disposed on the front surface of the printed board. The shield member has an opening that connects an inside and an outside of the shield member, at a position where the wiring passes through an outer edge of the shield area, and that extends in an extending direction of the wiring. The opening is electrically connected to a conductor disposed on an opposite side of the wiring from the opening, and the opening and the conductor form a waveguide surrounding the wiring.