Circuit Board EMI Seal Using Outer Surface Ground Strips
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional EMI shields, such as metallic chassis and module cages, hinder the visibility of LEDs due to small air holes and consume significant circuit board space, making them ineffective for providing reliable EMI protection and allowing LED light access.
Innovation Solution
A circuit board design with a boundary section featuring outer surface elongated ground strips that form an EMI seal, allowing EMI shields to mount and provide effective shielding for high-speed circuitry while keeping LEDs exposed for better access.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a metallic chassis completely surrounds the circuit board to provide EMI shielding, then EMI protection is improved, but LED visibility deteriorates due to small air holes
Solution Approach 1:
The circuit board is divided into two distinct sections: an EMI-sensitive section with high-speed circuitry that requires shielding, and a non-sensitive section with LEDs that remain exposed. The EMI shield is segmented to cover only the sensitive section, allowing LEDs to be visible while still providing EMI protection where needed.
Solution Approach 2:
EMI shielding is applied locally only to the section of the circuit board containing high-speed circuitry, rather than completely surrounding the entire board. This localized approach provides EMI protection for sensitive components while leaving the LED section exposed for visibility.
2Illumination intensity
If larger light pipe holes are provided in the metallic chassis to enable LED light access, then LED visibility is improved, but EMI shielding performance deteriorates
Solution Approach 1:
The circuit board is segmented into EMI-sensitive and non-sensitive areas, with the EMI shield configured to cover only the sensitive section. This allows light pipes to be positioned in the non-sensitive section where they can extract LED light without compromising the EMI shielding integrity of the sensitive section.
Solution Approach 2:
The circuit board boundary section acts as an intermediary between the EMI-sensitive and non-sensitive sections. The EMI shield is mounted on this boundary, creating a clear separation that allows light pipes to access LEDs in the non-sensitive area while the sensitive area remains shielded.
3Object-affected harmful factors
If a metallic module cage is used to protect individual circuit board components, then EMI shielding is improved, but circuit board space consumption increases
Solution Approach 1:
The EMI shield is merged with the circuit board structure itself, using the board's boundary section as the mounting surface. This integration eliminates the need for separate module cages and reduces overall space consumption while maintaining EMI shielding effectiveness for the sensitive circuitry.
Solution Approach 2:
The EMI shield serves multiple functions: it provides EMI protection for high-speed circuitry, defines a clear boundary between sensitive and non-sensitive sections, and allows the non-sensitive section to remain accessible for light pipe integration without requiring additional shielding structures.
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
This design enables reliable EMI shielding for high-speed circuitry while allowing LEDs to be visible and reducing the need for large light pipe holes, thus improving both EMI protection and LED visibility.
Implementation Method 1
The boundary section includes a set of outer surface elongated ground strips configured to form an EMI seal onto which a set of EMI shields is capable of mounting
Data Source
AI summary
A circuit board includes a first circuit board section which is configured to support a set of light emitting diodes, a second circuit board section which is configured to support high-speed electronic circuitry, and a boundary section which defines an EMI boundary between the first circuit board section and the second circuit board section. The boundary section includes a set of outer surface elongated ground strips configured to form an EMI seal onto which a set of EMI shields is capable of mounting. In some arrangements, the set of outer surface elongated ground strips take the form of metallic bands (e.g., layers of copper). Such bands can be integrated into the circuit board itself (e.g., during PCB fabrication), or added onto one or more of the circuit board surfaces (e.g., after PCB fabrication).