Optical Sensor Module EMI Shield Grounding With Conductive Vias
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Solution Overview
Problem
Conventional EMI shielding methods for optical sensors, such as metal can shielding, result in increased footprint, EM leakage, and internal crosstalk, while being costly and requiring complex assembly processes.
Innovation Solution
The method involves using a module substrate with protruding grounding pads and an EMI shield, employing cutouts, conductive coatings, and conductive vias to create a robust conductive connection, thereby preventing EM leakage and crosstalk.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional metal can shielding is used, then EMI shielding effect is achieved, but footprint increases due to minimum corner radius requirements
Solution Approach 1:
The patent integrates the EMI shield directly into the circuit board substrate by forming a conductive shield layer that extends from the bottom surface through internal ground vias to the top surface, merging the shield structure with the substrate itself. This eliminates the need for separate metal cans and their corner radius requirements, thereby reducing footprint while maintaining EMI shielding effectiveness.
2Object-affected harmful factors
If multiple metal cans are used to cover irregularly shaped components, then EMI shielding is improved, but EM leakage points increase
Solution Approach 1:
The patent creates a continuous conductive shield structure integrated into the circuit board substrate that provides seamless coverage over irregularly shaped components. The shield layer and internal ground vias form an unbroken conductive path, eliminating gaps and leakage points that would occur with multiple separate metal cans.
3Object-affected harmful factors
If circuit board level metal can shielding is used, then EMI shielding is achieved, but internal EMI crosstalk between components is not prevented
Solution Approach 1:
The patent extends the EMI shield into the vertical dimension by forming a conductive shield layer that spans from the bottom surface through internal ground vias to the top surface of the circuit board substrate. This three-dimensional conductive structure creates shielding barriers in multiple dimensions, effectively blocking internal EMI crosstalk between components while maintaining external EMI shielding.
4Object-affected harmful factors
If conventional metal can assembly is used, then EMI shielding is achieved, but assembly complexity and quality assurance costs increase
Solution Approach 1:
The patent integrates the EMI shield directly into the circuit board substrate through a multi-layer construction with internal ground vias, merging the shield function with the substrate manufacturing process. This eliminates separate assembly steps for attaching metal cans, reducing assembly complexity and quality assurance requirements while maintaining effective EMI shielding.
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 approach reduces EM leakage and crosstalk, enhances solder joint strength, and simplifies assembly, while maintaining effective EMI shielding without increasing the circuit board footprint.
Implementation Method 1
spraying the EMI shield with a conductive coating such that the conductive coating grounds the EMI shield to the one or more grounding pads
Implementation Method 2
Electromagnetic interference shielding creates a Faraday cage effect which attenuates radiation of electromagnetic (EM) waves and/or prevents EM emissions from circuit components
Data Source
AI summary
Methods, systems, and apparatuses for grounding of integrated external electromagnetic interference (EMI) shields are provided. A portion of a module substrate, different from a circuit board substrate, may protrude past the module as a location for one or more grounding pads to which the EMI shield is grounded. The EMI shield may cover at least a portion of the thickness of the module substrate. The EMI shield may be comprised of one or more parts, which may be coupled to one another. The module substrate may include conductive vias. The EMI shield may include a sprayed and/or printed coating. The EMI shield may include a darkened coating.