Flower-of-Life MEMS Gyroscope Resonator for High Q and Vibration Resistance
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Solution Overview
Problem
Prior art silicon disk resonator gyroscopes are sensitive to vibration, shock, and temperature, requiring large size, weight, and volume to mitigate these effects, and have limited resonance frequency and Q-factor.
Innovation Solution
A high-Q MEMS silicon Flower-of-life Vibratory Gyroscope (FVG) resonator design featuring an anchor, outer stiffener ring, and curved springs arranged in a flower-of-life pattern, with a high aspect ratio and rotational symmetry, which reduces sensitivity to vibration and temperature and increases resonance frequency and Q-factor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If prior art silicon disk resonator gyroscopes are used, then the device can operate at lower resonance frequencies around 14 kHz, but the Q-factor is limited to around 80,000 and the device is sensitive to vibration and temperature
Solution Approach 1:
The patent applies curved springs with specific curvature radii instead of straight springs. The curved geometry allows the springs to expand and contract radially during vibration, reducing stress concentration and improving the Q-factor. The curvature also helps distribute thermal stresses more evenly, reducing temperature sensitivity.
Solution Approach 2:
The patent changes key geometric parameters including the aspect ratio of springs (length to width), curvature radii, and the dimensions of stiffener rings. By optimizing these parameters, the resonator achieves higher Q-factor (>150,000) and higher resonance frequency (>30 kHz) while reducing sensitivity to external disturbances.
2Object-affected harmful factors
If prior art DRGs are designed with larger size to reduce vibration and temperature effects, then sensitivity to vibration and shock is reduced, but the device weight and volume increase
Solution Approach 1:
The patent uses a composite structure combining silicon resonator elements with specific material properties. The silicon-based resonator with optimized geometry achieves high mechanical quality factor without requiring increased size, thereby maintaining low weight and volume while reducing vibration sensitivity.
Solution Approach 2:
The resonator is segmented into multiple functional components: curved springs for vibration isolation, stiffener rings for structural support, and a central mass for inertial sensing. This segmentation allows each component to be optimized independently, achieving high vibration resistance without proportional increases in overall size.
3Object-affected harmful factors
If the resonance frequency is increased to reduce vibration sensitivity, then the device becomes less sensitive to vibration and shock, but the Q-factor and manufacturing precision requirements increase
Solution Approach 1:
The patent optimizes geometric parameters such as spring thickness, width, length, and curvature radii to achieve resonance frequencies above 30 kHz. The aspect ratio of springs is specifically designed to balance high frequency operation with manufacturability, ensuring that standard semiconductor fabrication processes can achieve the required precision.
Solution Approach 2:
The curved springs have asymmetric cross-sections with different thicknesses at different locations. This asymmetric design allows the springs to flex more easily in the vibration direction while maintaining structural integrity, enabling high resonance frequencies with relaxed manufacturing tolerances.
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 FVG achieves a resonance frequency greater than 30 kHz and a Q-factor of over 150,000, significantly reducing sensitivity to vibration and shock, and allowing for thermal tuning, enabling operation in harsh environments with improved bias stability and reduced acceleration sensitivity.
Implementation Method 1
a plurality of curved springs between the anchor and the outer stiffener ring
Implementation Method 2
a thermoelastic damping limited quality factor (QTED) greater than 150,000
Data Source
AI summary
A resonator includes an anchor, an outer stiffener ring on an outer perimeter of the resonator, and a plurality of curved springs between the anchor and the outer stiffener ring.