MEMS Acoustic Sensor Slit Covering Design
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Solution Overview
Problem
The existing MEMS acoustic sensors have limited acoustic performance due to the restricted area of the piezoelectric functional layer, which is constrained by the polymer layer with a smaller Young's modulus, limiting the diaphragm's vibration area and preventing further improvements in acoustic performance.
Innovation Solution
A MEMS acoustic sensor design featuring a base with structural layers and a piezoelectric functional layer, where the flexible connector has a smaller Young's modulus than the structural layers, forming slits that allow the piezoelectric functional layer to extend and cover these slits, thereby increasing the effective vibration area of the diaphragm.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a polymer layer with smaller Young's modulus is used on the electrode layer, then the piezoelectric functional layer area is restricted to the cavity range, but the diaphragm vibration area is limited, resulting in inability to improve acoustic performance
Solution Approach 1:
The patent divides the support structure into multiple independent structural layers (first structural layer, second structural layer, etc.) with different Young's modulus values. Each structural layer can be independently designed and optimized, allowing the piezoelectric functional layer to extend beyond the cavity range while maintaining structural integrity. This segmentation enables the diaphragm to have a larger vibration area without compromising the support provided by the polymer layer.
Solution Approach 2:
The patent employs a composite structure combining multiple layers with different material properties (Young's modulus values). The structural layers have progressively smaller Young's modulus values compared to the piezoelectric plate, creating a gradient structure that provides both support and flexibility. This composite approach allows the piezoelectric functional layer to extend beyond the cavity range while maintaining the necessary mechanical support, thereby increasing the diaphragm vibration area and improving acoustic performance.
2Area of moving object
If the piezoelectric functional layer area is extended beyond the cavity range, then the diaphragm vibration area is increased, but the structural support and sealing may be compromised
Solution Approach 1:
The support structure is segmented into multiple structural layers, each providing localized support to different regions of the piezoelectric functional layer. This segmentation allows the piezoelectric layer to extend beyond the cavity range while maintaining structural integrity through the distributed support provided by multiple layers rather than relying on a single polymer layer.
Solution Approach 2:
The patent uses a composite structure with multiple structural layers having different Young's modulus values to provide graded support to the extended piezoelectric functional layer. This composite approach ensures that the piezoelectric layer has sufficient structural support even when extending beyond the cavity range, maintaining both strength and flexibility where needed.
3Area of moving object
If the piezoelectric functional layer area is extended beyond the cavity range, then the diaphragm vibration area is increased, but the sealing and flexibility may be affected
Solution Approach 1:
The sealing structure is segmented into multiple structural layers, each contributing to the sealing function in different regions. This segmentation allows the piezoelectric functional layer to extend beyond the cavity range while maintaining effective sealing through the distributed sealing action of multiple layers, each positioned and dimensioned to contribute to the overall seal integrity.
Solution Approach 2:
The patent employs a composite sealing structure with multiple structural layers having different material properties. This composite approach provides both sealing functionality and flexibility in the extended regions beyond the cavity range, allowing the piezoelectric functional layer to expand while maintaining effective sealing through the coordinated action of multiple layers with appropriate mechanical properties.
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 design enhances the acoustic performance by increasing the vibration area of the diaphragm, allowing for improved sound production and consistency, while maintaining low power consumption and small size.
Implementation Method 1
The piezoelectric functional layer deforms after being energized, which drives the diaphragm to vibrate and produce sound
Implementation Method 2
a flexible connector completely covering the slit; wherein a Young's modulus of the flexible connector is smaller than a Young's modulus of the structural layer
Data Source
AI summary
One of the main objects of the present invention is to provide a MEMS acoustic sensor with improved acoustic performance and liability. To achieve the above-mentioned objects, the present invention provides a MEMS acoustic sensor, including: a base with a cavity; a number of structural layers fixed on the base, each including a fixed end fixed to the base and a suspension end extending from the fixed end for being suspended above the cavity, the suspension end being spaced from the base for forming a slit; a piezoelectric functional layer on the suspension end; and a flexible connector completely covering the slit; wherein a Young's modulus of the flexible connector is smaller than a Young's modulus of the structural layer.