Single Proof-Mass 3-Axis Gyroscope with Integrated Suspension
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Solution Overview
Problem
Existing micromachined 3-axis gyroscope and accelerometer systems require multiple sensors and proof-masses, leading to increased size and cost, and complex control electronics due to separate drive loops for each axis, which is not suitable for cost-effective and compact applications.
Innovation Solution
A micromachined monolithic 3-axis gyroscope and accelerometer design utilizing a single center-anchored proof-mass with unique partitioning and flexure structures to decouple response modes, allowing for single drive-mode oscillation and reduced cross-axis sensitivity, thereby simplifying control electronics and minimizing size and cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple separate sensors and proof-masses are used to form a 3-axis gyroscope cluster, then each axis can be detected independently, but the size and cost of the system increases excessively
Solution Approach 1:
The patent merges multiple separate proof-masses into a single integrated proof-mass structure that can detect all three acceleration axes simultaneously. The single proof-mass is designed with multiple suspension beams arranged in specific geometries (x-axis beams, y-axis beams, and z-axis beams) that enable independent detection of acceleration in all three directions through coupled oscillation modes.
Solution Approach 2:
The single proof-mass structure serves multiple functions by detecting acceleration along all three axes (x, y, and z) simultaneously. The proof-mass is designed with universal sensitivity to all three acceleration directions through its multi-directional suspension beam configuration, eliminating the need for separate proof-masses for each axis.
2Measurement precision
If multiple separate sensors are integrated into a 3-axis gyroscope cluster, then comprehensive 3-axis detection is achieved, but the cost increases due to separate drive and sense electronics for each sensor
Solution Approach 1:
The patent combines multiple separate drive loops into a single drive loop that simultaneously drives the proof-mass in multiple directions. The single drive electrode structure generates coupled oscillations that excite the proof-mass for detection in all three axes, eliminating the need for separate drive electronics for each sensor.
Solution Approach 2:
The single drive electrode and control electronics system serve multiple functions by enabling simultaneous detection across all three axes. The universal drive mechanism creates coupled oscillation modes that allow the single proof-mass to function as a multi-axis sensor, reducing the need for separate drive and sense electronics for each axis.
3Measurement precision
If multiple proof-masses are used for each acceleration axis, then accurate 3-axis acceleration detection is achieved, but the size and cost of the integrated sensor increases
Solution Approach 1:
The patent merges multiple proof-masses into a single proof-mass structure with integrated suspension beams for all three axes. The single proof-mass is designed with x-axis suspension beams, y-axis suspension beams, and z-axis suspension beams that are coupled together, allowing one compact structure to replace multiple separate proof-mass assemblies.
Solution Approach 2:
The patent implements a nested structure where the suspension beams for different axes are integrated within a single compact proof-mass assembly. The x-axis, y-axis, and z-axis suspension beams are arranged in a nested configuration that allows all three detection functions to coexist in a single small volume, significantly reducing the overall sensor size.
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 solution enables efficient 3-axis angular rate and acceleration detection with reduced complexity and cost, achieving significant size reduction and minimizing cross-axis sensitivity, making it suitable for consumer, automotive, and aerospace applications.
Implementation Method 1
the drive electrode and the central suspension system are configured to oscillate the 3-axis gyroscope about a z-axis normal to the x-y plane at a drive frequency
Implementation Method 2
a central suspension system configured to suspend the 3-axis gyroscope from the single, central anchor
Implementation Method 3
the single proof-mass 3-axis gyroscope can include symmetrical x-axis proof-mass sections configured to move anti-phase along the x-axis in response to z-axis angular motion
Data Source
AI summary
This document discusses, among other things, a cap wafer and a via wafer configured to encapsulate a single proof-mass 3-axis gyroscope formed in an x-y plane of a device layer. The single proof-mass 3-axis gyroscope can include a main proof-mass section suspended about a single, central anchor, the main proof-mass section including a radial portion extending outward towards an edge of the 3-axis gyroscope sensor, a central suspension system configured to suspend the 3-axis gyroscope from the single, central anchor, and a drive electrode including a moving portion and a stationary portion, the moving portion coupled to the radial portion, wherein the drive electrode and the central suspension system are configured to oscillate the 3-axis gyroscope about a z-axis normal to the x-y plane at a drive frequency.