Ingress Protection Mechanism for MEMS Sensor Housing
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Solution Overview
Problem
Autonomous vehicle sensors, particularly micro-electromechanical systems (MEMS) like microphones, are vulnerable to moisture and debris ingress, which can degrade their performance due to the harsh environmental conditions encountered during vehicle operation.
Innovation Solution
A protective sub-assembly is designed to prevent the ingress of moisture and debris into sensor components, featuring a t-protector mounted on a face-plate with a membrane covering the acoustic port, secured using fasteners or adhesives and protected by an o-ring, ensuring effective sealing while allowing sound passage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If MEMS sensors are exposed to the environment for data collection, then sensor functionality is enabled, but moisture and debris ingress degrades performance
Solution Approach 1:
The sensor assembly is divided into separate functional components: a face-plate with acoustic port for environmental exposure, a membrane for selective blocking, and internal sensor components. This segmentation allows different parts to serve different functions - the face-plate enables sound passage while the membrane prevents contaminant ingress, resolving the contradiction between sensor functionality and protection.
Solution Approach 2:
A membrane is introduced as an intermediary component between the external environment and the MEMS sensor. This membrane selectively allows acoustic waves to pass through while blocking moisture and debris particles. The intermediary enables the sensor to function in harsh environments without direct exposure to harmful contaminants.
2Reliability
If a protective membrane is added to block moisture and debris, then sensor protection is improved, but device complexity increases
Solution Approach 1:
Multiple protective functions are merged into a single integrated face-plate assembly that includes the membrane, sealing structures, and mounting features. Rather than adding separate protective components, the design combines protection functions into the existing structural elements, minimizing complexity while achieving reliable sensor protection.
Solution Approach 2:
The face-plate assembly serves multiple functions simultaneously: it provides structural support, enables acoustic passage, seals the sensor environment, and mounts the membrane for contamination protection. This multi-functionality reduces the need for additional specialized components, keeping the overall device complexity manageable while achieving comprehensive protection.
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 MEMS sensors from environmental hazards, enhancing their reliability and longevity by preventing moisture and debris from reaching sensitive components, thus maintaining accurate data collection and vehicle operation.
Implementation Method 1
protected by an o-ring, ensuring effective sealing
Implementation Method 2
a membrane covering the acoustic port
Data Source
AI summary
The disclosed technology provides solutions for preventing the ingress of potentially harmful materials, such as moisture and debris, into a sensor housing. In some aspects, an ingress-protection sub-assembly is provided. The sub-assembly can include a t-protector mounted to an outer surface of a face-plate, wherein the t-protector is disposed above an inlet in the face-plate, a printed circuit board (PCB) mounted to an inner surface of the face-plate, and a membrane disposed between the PCB and the face-plate. Methods for assembling and mounting a sub-assembly are also provided.