Knit EMI Shield Wire Positioning via Nonmetallic Yarn Loops
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Solution Overview
Problem
Woven wire electromagnetic interference (EMI) shields are difficult to manufacture due to the stiffness of metal wire, leading to inconsistent mesh sizes and performance over time, allowing EMI to pass through as the wire positions shift during installation or use.
Innovation Solution
A knit EMI shield using nonmetallic yarn with inserted wires, where the yarn loops fix the wires in place to maintain their optimal position, preventing movement and ensuring consistent EMI shielding, and the wires extend for grounding connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If woven wire EMI shields are manufactured using traditional weaving processes, then EMI shielding function is achieved, but manufacturing complexity and difficulty increase due to wire stiffness
Solution Approach 1:
The patent changes the manufacturing method from weaving to knitting, which fundamentally alters how the structure is formed. Knitting allows for more flexible handling of wire materials and produces a structure where wires are less prone to shifting, thereby reducing manufacturing difficulty while maintaining EMI shielding effectiveness
Solution Approach 2:
The patent uses composite construction by inserting wires into a knit fabric structure. This combination of knit fabric and metal wires creates a hybrid structure that is easier to manufacture than pure woven wire shields while maintaining the EMI shielding function through the embedded wire network
2Manufacturing precision
If woven wire EMI shields are installed and used over time, then EMI shielding is provided initially, but mesh size consistency deteriorates as wire positions shift
Solution Approach 1:
The patent changes the structural configuration from a rigid woven mesh to a knit structure with embedded wires. The knit structure's inherent flexibility and the way wires are integrated into the fabric prevent wire migration and mesh distortion over time, maintaining both manufacturing precision and long-term stability
Solution Approach 2:
The patent segments the EMI shielding function from the structural framework by inserting wires into a knit fabric rather than relying on a pure wire mesh. This segmentation allows the knit structure to provide stable positioning while the embedded wires provide EMI shielding, preventing the mesh size inconsistency that occurs in traditional woven shields
Data Source
AI summary
An electromagnetic interference (EMI) shield assembly and method of construction is provided. The assembly includes a body having a wall of warp knit nonmetallic yarn having opposite sides extending generally parallel with one another between opposite ends and a plurality of weft inserted metal wires. The wire is inserted to provide discrete bundles each arranged in side-by-side relation with one another and extending beyond the opposite sides of the wall to provide a plurality of exposed free ends. The nonmetallic yarn is looped about the wires, thereby fixing the wire relative to the nonmetallic yarn and to other wires in an optimal EMI shielding position. Metal brackets adapted for ready attachment to a source of electrical ground are attached to the exposed free ends. The individual bundles of wires extend parallel to one another, with a gap having a predetermined width extending between the adjacent bundles.