Three-Axis MEMS Gyroscope Layout for Decoupled Z-Axis Detection
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Solution Overview
Problem
Existing MEMS gyroscopes suffer from low efficiency in Coriolis force transformation, inefficient utilization of chip area, and significant orthogonal errors due to the arrangement of X/Y proof mass and Z proof masses, leading to reduced detection precision.
Innovation Solution
A fully-decoupled three-axis MEMS gyroscope design with an annularly arranged X/Y proof mass outside Z proof masses and Z decoupled masses, utilizing in-plane translation motion for detection and driving modes, and incorporating symmetrical mass distributions and elastic connections to minimize interference and coupling errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If Z proof masses and driving members are arranged outside the X/Y proof mass, then chip area can be utilized, but Coriolis force transformation efficiency decreases and orthogonal error increases
Solution Approach 1:
The proof mass system is segmented into independent X/Y proof masses and Z proof masses arranged in different planes. The X/Y proof masses are positioned in the X-Y plane while Z proof masses are positioned in the Z plane, with each serving distinct detection functions. This segmentation eliminates interference between axes and reduces orthogonal error while maintaining efficient chip area utilization.
Solution Approach 2:
The design transitions from a two-dimensional arrangement to a three-dimensional configuration by stacking X/Y proof masses in the X-Y plane and Z proof masses in the Z plane at different height levels. This dimensional separation allows independent operation of each axis without mutual interference, improving measurement precision while effectively utilizing chip area.
2Area of stationary object
If X/Y proof mass and Z proof masses are arranged in the same plane, then chip area utilization is improved, but coupling error increases and detection precision decreases
Solution Approach 1:
The proof masses are arranged in three-dimensional space with X/Y proof masses positioned in the X-Y plane and Z proof masses positioned in the Z plane at different height levels. This spatial separation in the vertical dimension eliminates coupling between axes while maintaining effective chip area utilization through optimized layout.
Solution Approach 2:
Different regions of the chip are assigned specific functions with localized proof masses optimized for their respective detection purposes. X/Y proof masses are positioned in regions optimized for in-plane detection while Z proof masses are positioned in the vertical plane, with each local area having properties tailored to its detection function.
3Device complexity
If Z detection is not decoupled from X/Y detection, then device complexity is reduced, but orthogonal error increases and measurement precision decreases
Solution Approach 1:
The detection system is segmented into independent X/Y detection channels and Z detection channels with separate proof masses and electrode arrangements. This segmentation enables complete decoupling of detection modes, eliminating orthogonal error while maintaining manageable device complexity through modular design.
Solution Approach 2:
The Z decoupled masses act as intermediary elements that facilitate independent Z-axis detection without interfering with X/Y detection. These dedicated Z proof masses serve as mediators between the Z-axis motion and the detection electrodes, enabling clean separation of detection modes.
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
Enhances Coriolis force transformation, maximizes chip area utilization, reduces chip size and cost, and improves detection precision by decoupling Z detection from X/Y detection, thereby increasing sensitivity and stability.
Implementation Method 1
When applying angular velocity Ω, the gyroscope transfers energy to a sensitive mode due to the Coriolis effect, causing a vibrating disk to oscillate out-of-plane in relative driving. The magnitude of Ω can be obtained by detecting the displacement of the out-of-plane oscillation.
Implementation Method 2
each of the Z proof masses is elastically connected to one of the driving structures adjacent thereto
Data Source
AI summary
Provided are a fully-decoupled three-axis MEMS gyroscope and an electronic product. The gyroscope includes a substrate, an X/Y proof mass, Z proof masses, driving structures, and Z decoupled masses fixed to the substrate. The X/Y proof mass is annularly arranged outside the Z proof masses, the driving structures, and the Z decoupled masses; the X/Y proof masses are arranged oppositely along an x-axis direction; the driving structures are arranged oppositely along the x-axis direction outside the Z proof masses; and the Z decoupled masses are arranged oppositely along the x-axis direction at inner sides of the Z proof masses. The X/Y proof mass is elastically connected to the driving structures adjacent thereto, each Z proof mass is elastically connected to one driving structure adjacent thereto, and each Z decoupled mass is elastically connected to one Z proof mass adjacent thereto. The gyroscope has improved detection precision.