MEMS Accelerometer Anti-Phase Proof Masses
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Solution Overview
Problem
Conventional MEMS accelerometers face challenges in performance and reliability, particularly in mechanical and electrical sensitivities, and require improvements for commercial applications, including effective breakout forces for moving parts.
Innovation Solution
The design incorporates at least two proof masses with a flexible coupling to the substrate, allowing them to move in anti-phase directions normal and parallel to the substrate plane in response to acceleration, utilizing unbalancing torque and capacitive sensing for enhanced measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional single proof mass design is used, then device complexity is low, but measurement precision and sensitivity are insufficient
Solution Approach 1:
The single proof mass is divided into two separate proof masses (first proof mass and second proof mass) that can move independently. Each proof mass is connected to the substrate through separate flexible couplings, allowing differential measurement of acceleration forces and improving measurement precision while maintaining manageable device complexity
Solution Approach 2:
The two proof masses are combined into a single integrated mechanical structure with shared flexible couplings to the substrate. This merging approach allows the system to achieve enhanced measurement precision through differential motion while avoiding the complexity of completely separate measurement systems
2Reliability
If proof masses are rigidly coupled to substrate, then mechanical stability is high, but mechanical stress and reliability deteriorate
Solution Approach 1:
Flexible couplings in the form of thin film structures are used to connect the proof masses to the substrate. These flexible couplings allow controlled motion of the proof masses while reducing mechanical stress concentrations, thereby improving the reliability of moving parts and preventing failure under acceleration loads
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 configuration enhances the sensitivity and reliability of MEMS accelerometers by enabling precise measurement of acceleration in multiple directions, improving performance and adaptability to existing environments while reducing mechanical stress on moving parts.
Implementation Method 1
The at least two proof masses move in an anti-phase direction normal to a plane of the substrate in response to acceleration of the sensor via an unbalancing torque
Implementation Method 2
move in anti-phase in a direction parallel to the plane of the substrate in response to an acceleration of the sensor in the same direction via an unbalancing torque
Data Source
AI summary
A sensor is disclosed. The sensor includes a substrate and a mechanical structure. The mechanical structure includes at least two proof masses including a first proof mass and a second proof mass. The mechanical structure also includes a flexible coupling between the at least two proof masses and the substrate. The at least two proof masses move in an anti-phase direction normal to the plane of the substrate in response to acceleration of the sensor normal to the plane and move in anti-phase in a direction parallel to the plane of the substrate in response to an acceleration of the sensor parallel to the plane. The at least two proof masses move in a direction parallel to the plane of the substrate in response to an acceleration of the sensor parallel to the plane.