MEMS Angular Velocity Sensor with Dual Charge Amplifiers for Stable Detection
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Solution Overview
Problem
Existing MEMS sensors face challenges in achieving high accuracy for angular velocity detection due to issues like nonlinearity and instability in vibration states, which affect detection sensitivity and precision.
Innovation Solution
The sensor design incorporates a circuit section with two charge amplifiers having non-inverting inputs set to different potentials, along with electrostatic tuning and optimization of vibration directions, to correct vibration states and enhance detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional MEMS sensor design is used, then device simplicity is maintained, but detection accuracy and precision deteriorate due to nonlinearity and instability in vibration states
Solution Approach 1:
The sensor is divided into distinct functional sections: an element section containing the movable portion and electrodes, and a circuit section containing charge amplifiers and signal processing circuits. This segmentation allows independent optimization of each section, enabling high detection accuracy through specialized circuit design while maintaining clear functional boundaries that manage overall system complexity.
Solution Approach 2:
Charge amplifiers are introduced as intermediary components between the electrodes and the signal processing circuits. These amplifiers convert the small charges generated by the movable portion's vibration into measurable voltage signals, serving as a mediator that bridges the mechanical vibration domain and the electrical signal domain, thereby improving detection accuracy without requiring direct complex interaction between the mechanical and electrical systems.
2Measurement precision
If vibration state optimization is implemented, then detection sensitivity improves, but nonlinearity and instability increase
Solution Approach 1:
The circuit section processes signals from multiple electrodes and uses feedback mechanisms to maintain stable vibration states. The charge amplifiers and subsequent signal processing circuits continuously monitor the vibration signals and provide feedback control, enabling the system to maintain high detection sensitivity while compensating for and correcting nonlinearity and instability in the vibration states.
Solution Approach 2:
The system utilizes parameter changes in the vibration state, specifically the frequency shift caused by Coriolis force when the sensor rotates. By detecting and measuring these parameter changes (frequency shifts) rather than relying on absolute vibration state stability, the system achieves high detection sensitivity for angular velocity while the actual vibration state can naturally vary without compromising measurement accuracy.
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 improves the detection accuracy of angular velocity by stabilizing vibration states and reducing nonlinearity, resulting in more precise angular velocity measurements.
Implementation Method 1
a first gap being provided between the base face and the movable portion, and a plurality of fixed electrodes fixed to the base face and facing the movable portion
Data Source
Figure 1
Figure 2A~2B
Figure 3~4
AI summary
According to one embodiment, a sensor includes an element section and a circuit section. The element section includes a base including a base face, a fixed portion fixed to the base face, a movable portion supported by the fixed portion, a first gap being provided between the base face and the movable portion, and a plurality of fixed electrodes fixed to the base face and facing the movable portion. The plurality of fixed electrodes includes a first electrode and a second electrode. A first direction from the fixed portion to the first electrode is along a first plane along the base face. A second direction from the fixed portion to the second electrode is along the first plane and is inclined with respect to the first direction. The circuit section includes a first charge amplifier and a second charge amplifier.