Coaxial Gyro Accelerometer in Semiconductor Substrate
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Pendulating integrating gyroscopic accelerometers (PIGAs) are bulky, expensive due to high-precision machining requirements, and not optimal for many applications despite their high sensitivity and accuracy in inertial navigation systems.
Innovation Solution
An integrated interferometric gyroscope and accelerometer device using a resonating cantilever beam within a semiconductor substrate, incorporating a piezoresistor driver and sensor, and a semiconductor interferometric optical gyro with a spiraled waveguide, capable of sensing both linear and rotational forces simultaneously.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a pendulating integrating gyroscopic accelerometer (PIGA) is used to achieve high sensitivity and accuracy in inertial navigation systems, then measurement precision is improved, but device size and weight increase
Solution Approach 1:
The patent combines the gyroscope and accelerometer into a single integrated device where the resonating cantilever beam serves dual purposes: as the accelerometric sensing element and as the gyroscopic rotation reference. This merging eliminates the need for separate PIGA components, thereby reducing overall device weight while maintaining high measurement precision through the coupled sensing mechanisms.
Solution Approach 2:
The patent replaces the traditional mechanical PIGA structure with a semiconductor-based resonating cantilever beam system that uses piezoresistive sensing and optical interferometry. This substitution of mechanical systems with semiconductor and optical technologies significantly reduces device weight and size while achieving equivalent or superior measurement precision.
2Measurement precision
If a pendulating integrating gyroscopic accelerometer (PIGA) is used to achieve high sensitivity and accuracy in inertial navigation systems, then measurement precision is improved, but manufacturing cost increases due to high-precision machining requirements
Solution Approach 1:
The patent replaces complex mechanical PIGA components with semiconductor-fabricated resonating cantilever beams and integrated piezoresistive sensors. This substitution eliminates the need for high-precision mechanical machining, as the structures are created through standard semiconductor fabrication processes, thereby significantly reducing manufacturing cost while maintaining measurement precision.
Solution Approach 2:
The patent changes the manufacturing approach from mechanical machining to semiconductor fabrication processes. By parameterizing the design in terms of semiconductor layer thickness, doping concentrations, and lithographic patterns, the manufacturing process becomes scalable and cost-effective, eliminating the need for expensive high-precision machining while achieving the required measurement precision.
3Volume of moving object
If a resonating cantilever beam with piezoresistor driver and sensor is integrated into a semiconductor substrate, then device size is reduced, but device complexity increases
Solution Approach 1:
The patent merges the driver and sensor piezoresistors into the same resonating cantilever beam structure, along with the optical interferometric gyro components. This consolidation into a single integrated semiconductor device reduces overall device size. The complexity is managed through co-design of all components during the semiconductor fabrication process, where the driver, sensor, and optical elements are created in the same manufacturing sequence.
Solution Approach 2:
The resonating cantilever beam serves multiple functions simultaneously: it acts as the accelerometric sensing element, the gyroscopic rotation reference, and the mechanical resonator for both sensing modes. This multi-functionality reduces the number of separate components needed, thereby reducing device size. The universal design is achieved through careful structural optimization of the cantilever beam geometry and material properties.
4Adaptability or versatility
If a spiraled waveguide is incorporated in the substrate around the RC beam, then rotational sensing capability is added, but device complexity increases
Solution Approach 1:
The patent merges the optical interferometric gyro function into the same semiconductor substrate as the resonating cantilever beam accelerometer. The spiraled waveguide is integrated alongside the RC beam using the same fabrication processes, creating a unified device structure. This merging adds rotational sensing capability while minimizing the increase in device complexity through shared manufacturing steps and integrated optical pathways.
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 provides a compact, cost-effective device that maintains high sensitivity and accuracy, enabling efficient use in various applications by integrating gyroscopic and accelerometric functions within a single semiconductor substrate.
Implementation Method 1
The driver electrothermally resonates the RC beam
Implementation Method 2
The sensor piezoresistively senses a signal that relates to an acceleration force out-of-plane of the RC beam
Implementation Method 3
The gyro senses rotational motion about the axis that is the same as the acceleration vector
Data Source
AI summary
A coaxial gyro accelerometer device in a semiconductor substrate for simultaneously sensing coaxial linear and rotational forces. An exemplary device includes a resonating cantilever beam within a substrate and a package having a resonating cavity. The package supports the substrate while allowing the beam to resonate. The substrate also includes a piezoresistor driver, a piezoresistor sensor, and a semiconductor interferometric optical gyro. The piezoresistor driver and sensor are incorporated within the beam. The driver electrothermally resonates the beam. The sensor piezoresistively senses a signal that relates to an acceleration force out-of-plane of the beam. A waveguide of the semiconductor interferometric optical gyro is incorporated in the substrate around the beam. The gyro senses rotational motion about the axis that is the same as the acceleration vector (out-of-plane of the beam). The gyro also includes a laser source and a light detector. The beam is formed contiguously from the semiconductor substrate.