Piezoelectric Ring Gyroscope Bridge Masses
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Solution Overview
Problem
Existing microelectromechanical systems (MEMS) gyroscopes face challenges in detecting angular rotation rates due to small capacitance values and limited space for transducers, which affects the accuracy and compatibility with standard packaging requirements.
Innovation Solution
The use of piezoelectric transducers to drive and detect the primary and secondary resonance modes in a ring gyroscope, along with the attachment of mass elements via narrow bridge connectors to adjust resonance properties, allowing for improved dimensioning and signal strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If capacitive transducers are used to detect angular rotation rates in MEMS gyroscopes, then the device can be manufactured with standard processes, but the capacitance values are small which limits detection accuracy and signal strength
Solution Approach 1:
The patent replaces capacitive transducers with piezoelectric transducers for both driving and detecting functions. The piezoelectric transducer converts electrical signals to mechanical vibrations (driving) and mechanical vibrations to electrical signals (detecting), providing stronger signal output and better detection accuracy compared to capacitive transducers while maintaining compatibility with standard silicon manufacturing processes.
Solution Approach 2:
The patent changes the physical principle from capacitive coupling to piezoelectric effect, fundamentally altering the transduction mechanism. This parameter change enables stronger electrical signals to be generated from mechanical vibrations, directly addressing the limitation of small capacitance values and improving signal-to-noise ratio.
2Adaptability or versatility
If the ring structure is made compact to fit standard packaging requirements, then compatibility with standard silicon device packaging is improved, but the space for transducers is limited which affects measurement accuracy
Solution Approach 1:
The patent strategically positions piezoelectric transducers at specific locations on the ring structure where they can maximize their effectiveness. By placing transducers at optimal positions (e.g., at 45 degrees to the oscillation axes), the system achieves high measurement accuracy without requiring excessive space, thus maintaining compatibility with standard packaging while improving precision.
Solution Approach 2:
The replacement of capacitive transducers with piezoelectric transducers reduces the space required for transducer elements. Piezoelectric transducers can be fabricated as thin films directly on the ring structure, requiring minimal additional space compared to capacitive transducer configurations, thereby enabling compact designs that fit standard packaging.
3Reliability
If mass elements are attached to the ring to adjust resonance properties, then the resonance frequency and Q-value can be optimized, but the device complexity increases
Solution Approach 1:
The patent integrates mass elements as part of the ring structure, creating a composite system where the mass elements and ring work together as a unified resonator. This integration approach optimizes resonance properties while minimizing the increase in device complexity, as the mass elements are fabricated using the same semiconductor processing techniques as the ring structure itself.
Solution Approach 2:
The patent uses mass elements to adjust and optimize the resonance frequency and Q-value of the ring oscillator. By carefully selecting the mass, position, and distribution of attached elements, the system achieves desired resonance characteristics without requiring complex control mechanisms, thereby improving reliability while keeping device complexity manageable.
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 enhances the signal-to-noise ratio, reduces errors from misalignment, and increases the output signal amplitude, making it more compatible with standard silicon device packaging while maintaining high resonance frequency and Q-value.
Implementation Method 1
a piezoelectric transducer configured to drive the ring into oscillation
Implementation Method 2
a piezoelectric transducer configured to detect oscillation of the ring
Implementation Method 3
When a ring in drive oscillation undergoes an angular rotation rate Ω about the z-axis (perpendicular to the xy-plane defined by the ring), the ring is affected by the Coriolis force FC
Implementation Method 4
the oscillation mode will be labelled called the 'primary resonance mode', since the ring typically oscillates in resonance
Data Source
AI summary
A ring gyroscope which comprises first and second transversal symmetry axes and first and second diagonal symmetry axes in the ring plane. The gyroscope further comprises one or more primary piezoelectric split transducers configured to drive the ring into resonance oscillation and one or more secondary piezoelectric split transducers configured to sense the oscillation of the ring. The gyroscope further comprises four or more mass elements which form a symmetrical mass distribution in relation to both the first and second transversal symmetry axes and to the first and second diagonal symmetry axes, wherein each mass element is attached to the ring from a bridge connector and the bridge connectors are evenly distributed along the ring.