Batch-Micromachined 3D Shell Gyroscope for Low-Cost Inertial Navigation
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Solution Overview
Problem
Current quartz hemispherical resonator gyroscopes (HRG) are expensive and unsuitable for portable applications due to their high size, weight, and power (SWaP) metrics, limiting their use in man-portable navigation systems despite their precision.
Innovation Solution
A three-dimensional batch-micromachined shell gyroscope with elastic wave propagation and precession, fabricated using extended glass-blowing technology, which allows for batch production of spherical or hemispherical shells with integrated driving and sensing electrodes, enabling precise angle and angular rate measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional boutique manufacturing process is used for HRG, then high precision inertial navigation performance is achieved, but extremely high cost and large size are resulted
Solution Approach 1:
The patent segments the manufacturing process into standardized fabrication steps that can be performed in batches on multiple wafers simultaneously. The gyroscope structures are divided into repeating units that can be processed together through photolithography, etching, and deposition steps, enabling parallel production while maintaining precision requirements.
Solution Approach 2:
The patent changes the manufacturing parameters from single-unit boutique processes to batch-processing parameters. By adjusting wafer dimensions, batch sizes, and processing temperatures to optimize for high-volume production, the cost per unit decreases while maintaining the required measurement precision through controlled parameter specifications.
2Measurement precision
If conventional HRG is designed for precision navigation, then high accuracy is achieved, but large size and high power consumption make it unsuitable for portable applications
Solution Approach 1:
The patent transitions from macro-scale HRG designs to micro-scale implementations by fabricating gyroscope structures on silicon wafers with dimensions reduced by factors of 100 or more. This dimensional change enables portable applications while maintaining precision through microfabrication techniques that control structural geometry at the micrometer level.
Solution Approach 2:
The patent creates multiple copies of the gyroscope structure on each silicon wafer, with each wafer containing numerous identical or variations of the basic gyroscope unit. This copying approach enables selection of the best-performing units while distributing the manufacturing process across many identical templates, ensuring consistency and precision across all devices.
3Productivity
If batch fabrication is implemented, then productivity and cost-effectiveness are improved, but manufacturing complexity increases
Solution Approach 1:
The patent employs universal photolithography masks and etching processes that can fabricate multiple gyroscope structures simultaneously on a single wafer. The same fabrication equipment and process parameters are used across all batches, standardizing the complexity management while enabling high productivity through parallel processing of multiple devices.
Solution Approach 2:
The patent replaces manual boutique manufacturing operations with automated semiconductor fabrication equipment. Photolithography, plasma etching, and chemical vapor deposition processes substitute for hand-crafted mechanical assembly, reducing per-unit complexity while increasing overall productivity through automation and batch processing capabilities.
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 the production of portable, low-cost, high-precision inertial sensors suitable for consumer and military navigation systems by leveraging wafer-scale self-inflation techniques and multi-material structures, overcoming the cost and size limitations of traditional HRG technologies.
Implementation Method 1
heating the glass layer to a plastic state and gas in the plurality of cavities
Implementation Method 2
heating the glass layer to a plastic state and gas in the plurality of cavities
Implementation Method 3
heating the glass layer to a plastic state and gas in the plurality of cavities
Implementation Method 4
a three-dimensional batch-micromachined shell adapted to vibrate and support elastic wave propagation and wave precession
Data Source
AI summary
A vibratory sensor is fabricated as a three-dimensional batch-micromachined shell adapted to vibrate and support elastic wave propagation and wave precession in the shell or membrane and at least one driving electrode and preferably a plurality of driving electrodes directly or indirectly coupled to the shell to excite and sustain the elastic waves in the shell. The pattern of elastic waves is determined by the configuration of the driving electrode(s). At least one sensing electrode and preferably a plurality of sensing electrodes are provided to detect the precession of the elastic wave pattern in the shell. The rotation of the shell induces precession of the elastic wave pattern in the shell which is usable to measure the rotation angle or rate of the vibratory sensor.