Multilayer Circuit Board Shielding via Segmented Grounded Patterns
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Solution Overview
Problem
Existing multilayer circuit boards and modules suffer from weak shielding effectiveness due to open-ended line-shaped conductive patterns, leading to insufficient isolation between closely spaced wiring, external terminals, and via conductors, resulting in cross-talk and reduced isolation characteristics.
Innovation Solution
A multilayer circuit board design featuring a laminate with insulating layers, conductive patterns, and a shield electrode layer connected to ground potential, where surrounding conductive patterns with both ends connected to the shield electrode layer effectively shield elements from external interference, enhancing isolation characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If line-shaped conductive patterns with open ends are used for shielding, then the structure is simple and easy to manufacture, but the shielding effectiveness is weak and isolation characteristics are insufficient
Solution Approach 1:
The conductive pattern is segmented into multiple sections with through-holes at intervals, transforming a single continuous structure into a series of connected segments. This segmentation maintains manufacturing simplicity while improving shielding effectiveness by creating multiple shielding zones and reducing parasitic capacitance between adjacent conductive elements.
Solution Approach 2:
Through-holes are strategically positioned at specific locations along the conductive pattern where parasitic capacitance occurs. This local modification approach targets problem areas without changing the overall structure, maintaining ease of manufacture while locally improving shielding performance by interrupting electric field coupling.
2Volume of moving object
If closely spaced wiring and external terminals are disposed to achieve compact design, then device size is reduced, but cross talk occurs and isolation characteristics deteriorate
Solution Approach 1:
The conductive pattern with through-holes acts as an intermediary shielding structure positioned between closely spaced wiring and external terminals. This intermediate element redirects electric fields and reduces direct coupling between adjacent conductors, enabling compact layout while maintaining isolation characteristics.
Solution Approach 2:
The thin conductive pattern with periodic through-holes functions as a flexible shielding film that can be integrated into compact multilayer structures. This thin-film approach provides effective electromagnetic shielding without adding significant volume, allowing close spacing of components while preventing cross talk.
3Ease of manufacture
If traditional line-shaped conductive patterns are used, then manufacturing is simple, but parasitic capacitance occurs between both sides of the pattern
Solution Approach 1:
The conductive pattern incorporates through-holes creating a porous structure along its length. These periodic openings interrupt the continuous conductive path, reducing the effective capacitance between adjacent sides of the pattern while maintaining overall electrical connectivity through the through-holes to ground potential.
Solution Approach 2:
The continuous conductive pattern is segmented by introducing through-holes at regular intervals, dividing it into multiple shorter conductive sections. This segmentation reduces the accumulated parasitic capacitance that would exist in a long continuous pattern, while the through-holes provide alternative grounding paths.
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
The solution provides improved isolation characteristics by ensuring that the surrounding conductive patterns completely shield elements, reducing external noise impact and increasing manufacturing ease and non-defective rates compared to traditional designs.
Implementation Method 1
A shield electrode layer connected to a ground potential is provided on at least one side surface of the laminate
Implementation Method 2
WO 2012/105302 describes each of the line-shaped conductive patterns 204a to 204o as a conductive pattern for suppressing the occurrence of a parasitic capacitance between both sides thereof
Data Source
AI summary
A multilayer circuit board includes a laminate of insulating layers, conductive patterns each provided at an interlayer in the laminate, a via conductor extending through at least one of the insulating layers, and external terminals on a lower main surface of the laminate. A shield electrode layer connected to a ground potential is provided on at least one side surface of the laminate. At least one surrounding conductive pattern surrounding an element to be shielded is provided at an interlayer between corresponding ones of the insulating layers. Both ends of the surrounding conductive pattern are connected to the shield electrode layer.