Board Level Shield Frame with Integrated Fingers for EMI Leakage
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Solution Overview
Problem
Conventional board level shields (BLS) suffer from gaps or voids in their sidewalls that allow electromagnetic interference (EMI) to leak through, compromising shielding effectiveness.
Innovation Solution
A frame with integrally formed fingers or tabs that extend beyond the sidewalls to fill and cover these gaps, providing enhanced EMI shielding by aligning with and closing off openings in the BLS cover, and optionally forming electrical contact with the cover for improved attachment and reduced EMI leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional board level shields are used with stamped and folded sidewalls, then manufacturing is simplified, but gaps or voids remain that allow EMI leakage
Solution Approach 1:
The frame is segmented into multiple sidewalls with integrated fingers or tabs that extend between cover sidewalls. Each finger acts as an independent EMI barrier segment, collectively forming a complete shielding structure that blocks EMI leakage paths while maintaining manufacturing simplicity through stamping and folding operations.
Solution Approach 2:
The frame's fingers or tabs are nested between the cover's sidewalls, creating a layered shielding structure. The frame is positioned within the cover assembly, with fingers extending into the spaces between cover sidewalls to fill gaps and voids, effectively nesting the EMI barrier within the existing shield structure.
2Object-affected harmful factors
If a frame with fingers or tabs is added to fill gaps, then EMI shielding effectiveness is improved, but device complexity increases
Solution Approach 1:
The frame structure merges the EMI shielding function with the structural support function. The same frame that provides mechanical support for the cover also incorporates fingers or tabs that fill EMI gaps, combining multiple functions into a single component rather than adding separate EMI shielding elements.
Solution Approach 2:
The frame serves multiple functions: it provides structural support for the cover, acts as an EMI barrier through its integrated fingers or tabs, and potentially provides electrical contact paths. This multi-functionality reduces the need for additional components and minimizes overall device complexity while improving EMI shielding.
3Ease of operation
If the cover is made reusable and detachable, then ease of operation for rework is improved, but reliability of EMI shielding may be compromised
Solution Approach 1:
The frame's fingers or tabs are pre-positioned to make electrical contact with the cover's sidewalls before the cover is attached. This preliminary contact ensures that EMI shielding is established as soon as the cover is placed on the frame, maintaining shielding reliability while allowing the cover to be easily detached and reattached for rework operations.
Solution Approach 2:
The frame acts as an intermediary between the PCB and the detachable cover, maintaining EMI shielding continuity. The frame's fingers or tabs provide a consistent EMI barrier that remains in place when the cover is removed and reattached, ensuring shielding reliability is maintained throughout the rework process without requiring permanent modifications.
Data Source
AI summary
According to various aspects, exemplary embodiments are disclosed of frames for shielding assemblies. Exemplary embodiments are also disclosed of shielding assemblies including such frames. In exemplary embodiments, a frame for a board level shield (BLS) may include at least one finger or tab (broadly, a portion or contact) configured to fill, cover, or close off a gap or void defined by a cover's sidewalls to thereby inhibit or prevent EMI leakage through the gap or void.