PCB Conductive Mesh Shielding for MEMS Microphone EMI Control
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Solution Overview
Problem
Existing auditory prostheses face challenges with electromagnetic interference (EMI) and electrostatic discharge (ESD) affecting the performance of microphone assemblies, particularly in implantable devices, which can impair the acoustic sensor's functionality and require specific shielding constraints that limit the choice of microphone packages.
Innovation Solution
Incorporating an electrically conductive mesh within the printed circuit board (PCB) to shield the microphone assembly from EMI and ESD, allowing for customizable shielding and acoustic response, thereby decoupling the shielding requirements from the microphone package's performance attributes and reducing the assembly's thickness for implantable configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electromagnetic shielding is added to protect the acoustic sensor from EMI and ESD, then the sensor's reliability is improved, but the assembly's thickness increases
Solution Approach 1:
The patent combines the electromagnetic shielding function with the printed circuit board structure by integrating a conductive layer directly into the PCB. This merging of functions allows the shielding to be provided without adding separate shielding components that would increase assembly thickness, thereby maintaining sensor reliability while minimizing dimensional increases.
Solution Approach 2:
The printed circuit board is designed to serve multiple functions simultaneously: it provides structural support, electrical connections, and electromagnetic shielding. The conductive layer in the PCB acts as both an electrical pathway and an EMI/ESD shield, eliminating the need for dedicated shielding components that would increase thickness.
2Reliability
If specific shielding constraints are imposed on the microphone package, then the sensor's protection from EMI and ESD is improved, but the adaptability of microphone package selection is reduced
Solution Approach 1:
The patent introduces the printed circuit board with its integrated conductive layer as an intermediary between the external environment and the microphone sensor. This intermediary provides the necessary EMI and ESD protection at the PCB level, allowing the microphone package itself to remain unrestricted in its design choices and selection criteria.
Solution Approach 2:
The PCB serves as a universal protection platform that can accommodate various microphone packages without imposing specific shielding constraints on them. The conductive layer in the PCB provides standardized EMI and ESD protection that works with different microphone package designs, thereby enhancing adaptability.
3Reliability
If additional shielding components are added to the microphone assembly, then the protection from EMI and ESD is improved, but the device complexity increases
Solution Approach 1:
The patent merges the electromagnetic shielding function into the existing printed circuit board structure through the integration of a conductive layer. This eliminates the need for separate shielding components, brackets, or housings, thereby maintaining sensor protection while minimizing device complexity and assembly steps.
Solution Approach 2:
The printed circuit board provides its own electromagnetic shielding capability through the integrated conductive layer, making the shielding function self-contained within the existing structure. This self-service approach eliminates the need for additional dedicated shielding components and simplifies the overall assembly.
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 effectively shields the microphone assembly from EMI and ESD, enhances performance, and allows for a wider variety of microphone packages to be used, while reducing the overall thickness and improving compatibility with implantable devices.
Implementation Method 1
The portion is configured to allow the sound to propagate through the second hole and to at least partially shield the region containing the sensor from electromagnetic interference
Implementation Method 2
The sensor is configured to generate signals indicative of sound received by the sensor through the first hole
Data Source
AI summary
An assembly is provided which includes a package and a printed circuit board. The package includes a housing bounding a region and an acoustic sensor within the region. The housing includes a base with a first hole. The sensor is configured to generate signals indicative of sound received by the sensor through the first hole. The printed circuit board is in mechanical communication with the base and includes a second hole aligned with the first hole such that sound received by the second hole propagates through the first hole to the sensor. The printed circuit board further includes an electrically conductive layer, at least a portion of which extends across the second hole and is configured to allow the sound to propagate through the second hole and to at least partially shield the region containing the sensor from electromagnetic interference.