Gyro Sensor Beam Layout for Stable Resonant Frequency
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Solution Overview
Problem
Existing gyro sensors face reduced detection accuracy due to variations in the cross-sectional shape of elastic parts caused by uneven etching gas distribution during the dry etching process, leading to variations in resonant frequency.
Innovation Solution
The physical quantity sensor design includes a structure with specific beam configurations and spacing relationships to minimize the aperture ratio variations, reducing the impact of etching gas spreading and thereby stabilizing the resonant frequency and detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If dry etching is used to manufacture the sensor element, then manufacturing efficiency is improved, but the cross-sectional shape of elastic parts varies due to uneven etching gas distribution, reducing detection accuracy
Solution Approach 1:
The patent applies local quality by configuring beams with different aperture ratios in different regions of the etching pattern. Specifically, beams adjacent to the through-hole are designed with smaller aperture ratios to reduce etching gas spreading in that local region, while other beams maintain larger aperture ratios. This localized adjustment compensates for the uneven etching gas distribution and achieves consistent cross-sectional shapes across all beams.
Solution Approach 2:
The patent changes the aperture ratio parameter of beams based on their position relative to the through-hole. By adjusting this geometric parameter locally, the patent compensates for the varying etching conditions caused by gas spreading, thereby maintaining uniform cross-sectional shapes and resonant frequencies across all elastic parts.
2Measurement precision
If the aperture ratio of beams is increased to reduce resonant frequency variation, then detection accuracy is improved, but etching gas spreads more, causing greater cross-sectional shape variation
Solution Approach 1:
The patent implements local quality by differentiating the aperture ratios of beams based on their spatial relationship to the through-hole. Beams adjacent to the through-hole use smaller aperture ratios to counteract the pronounced gas spreading effect in that region, while beams farther away can use larger aperture ratios. This localized parameter adjustment achieves consistent cross-sectional shapes without requiring uniform reduction of all aperture ratios.
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 reduces the variation in resonant frequency and enhances detection accuracy by controlling the cross-sectional shape variations, resulting in more stable and reliable angular velocity sensing.
Implementation Method 1
the resonant frequency at each site of the elastic part varies
Implementation Method 2
the etching gas spreads unevenly, thus causing the cross-sectional shape of each site to vary
Implementation Method 3
An angular velocity about a Z-axis (or Y-axis) acting on the vibrator in such a vibrating state generates a Coriolis force
Data Source
AI summary
A gyro sensor includes: a spring having an inner span beam connected to an outer span beam via a turnaround beam; and a fixed driver that laterally faces the outer beam. A first beam is provided to the structure side of the outer beam so as to face the outer beam. T1 is a width of a space between the outer beam and the structure, T2 is a width of a space between the inner and outer beams, and T2<T1.