Annular Ground Pattern Shielding for PCB Noise Suppression
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Solution Overview
Problem
Existing electronic apparatuses face challenges in perfectly covering circuit elements generating noise with shield members due to signal lines connecting circuit elements inside the shield and external connectors on the printed board's surface, leading to incomplete noise suppression.
Innovation Solution
An electronic apparatus design featuring annular ground patterns surrounding shield areas on the printed board, with connectors and communication control circuits positioned outside these patterns, and shield members electrically connected to the ground patterns to prevent noise propagation, ensuring complete shielding without interrupting the ground patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a shield member is disposed to cover the circuit element serving as a noise generation source, then noise propagation is suppressed, but signal lines connecting the circuit element inside the shield member and external connectors cannot be properly routed
Solution Approach 1:
The printed board is divided into a shield area surrounded by the annular ground pattern and a non-shield area outside it. Circuit elements requiring noise suppression are placed within the shield area, while connectors are positioned in the non-shield area. This spatial segmentation allows signal lines to connect elements across the boundary without interrupting the ground pattern, resolving the conflict between noise suppression and signal routing.
Solution Approach 2:
The annular ground pattern serves as an intermediary structure between the shield member and the signal lines. It provides a continuous reference potential that allows signal lines to pass through or near the shield area without compromising either the shielding effectiveness or the signal integrity, thus mediating between noise suppression requirements and signal routing needs.
2Object-affected harmful factors
If connectors are disposed outside the ground pattern, then noise suppression is improved, but the distance between connectors and communication control circuits increases
Solution Approach 1:
The ground pattern is designed with an annular shape that provides different electromagnetic environment qualities in different regions. The area inside the annular ground pattern has enhanced noise suppression characteristics, while the area outside allows for connector placement. This local differentiation of electromagnetic properties enables connectors to be positioned outside the ground pattern for optimal noise suppression while maintaining reasonable connection distances through proper circuit layout.
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 propagation from communication control circuits by ensuring continuous ground patterns and secure electrical connections between shield members and connectors, enhancing noise suppression within the shield areas.
Implementation Method 1
a shield member disposed to face the printed board... the shield member covers the shield area and is fixed to the printed board such that a portion facing the ground pattern is electrically connected to the ground pattern
Implementation Method 2
an annular ground pattern surrounding, without interruption, a shield area including the plurality of communication control circuits is formed on a front surface of the printed board
Data Source
AI summary
Disclosed is an electronic apparatus including a printed board, a plurality of connectors mounted on the printed board, a plurality of communication control circuits that is mounted on the printed board and that controls communication through corresponding ones of the plurality of connectors, and a shield member disposed to face the printed board, in which an annular ground pattern surrounding, without interruption, a shield area including the plurality of communication control circuits is formed on a front surface of the printed board, the plurality of connectors is all disposed outside the ground pattern surrounding the shield area, and the shield member covers the shield area and is fixed to the printed board such that a portion facing the ground pattern is electrically connected to the ground pattern.