Integrated Semiconductor Strain Gauge for Multiaxial Measurement
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Solution Overview
Problem
Existing mechanical-quantity measuring devices face challenges in accurately measuring torque, axial force, and multiaxial strain with high precision due to variations in sensor sensitivity and adherence errors, and are prone to noise interference, especially in stress concentration fields and environments with external noise.
Innovation Solution
The solution involves forming multiple bridge circuits on a semiconductor chip with n-type and p-type diffusion resistors oriented in specific directions to maximize sensitivity and minimize interference, including the use of polysilicon wiring resistors and temperature compensation, and integrating these circuits with amplifiers to reduce noise and improve precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If two pieces of strain measuring chips are adhered to the rotation axis to measure torque and axial force, then measurement capability is provided, but measurement precision deteriorates due to variation in sensor sensitivity and adherence errors
Solution Approach 1:
The patent merges multiple strain measuring chips into a single integrated semiconductor substrate, forming a multi-element strain gauge array. This eliminates the adherence errors and sensitivity variations that occur when separate chips are adhered to the measurement object, while maintaining the capability to measure multiple strain components simultaneously.
Solution Approach 2:
The semiconductor substrate is segmented into multiple independent strain measurement regions, each capable of measuring specific strain components. This segmentation allows simultaneous measurement of torque and axial force with high precision by isolating each measurement function within the integrated structure.
2Adaptability or versatility
If multiple strain measuring chips are adhered to measure multiaxial strain, then measurement coverage is improved, but adherence errors increase and measurement precision deteriorates
Solution Approach 1:
Multiple strain measuring elements are merged into a single semiconductor substrate, eliminating the adherence errors associated with multiple separate chips. The integrated structure ensures consistent reference surfaces and eliminates variations in adherence quality across different measurement locations.
Solution Approach 2:
The semiconductor substrate serves as a universal platform that can simultaneously measure multiple strain components in different directions. This multi-functional design provides comprehensive measurement coverage while maintaining high precision through the unified substrate structure.
3Adaptability or versatility
If multiple strain measuring chips are adhered for multiaxial strain measurement, then measurement capability is enhanced, but the required area increases causing separation of measurement points
Solution Approach 1:
Multiple measurement functions are merged into a single compact semiconductor substrate, eliminating the need for separate chips and reducing the total area required. The integrated structure allows multiple strain components to be measured at closely spaced locations within the same substrate footprint.
Solution Approach 2:
The patent utilizes the third dimension (depth into the substrate) to separate measurement functions, allowing multiple strain measurement elements to be positioned at different depths and orientations within the same planar footprint, thereby reducing the required surface area.
4Measurement precision
If strain measuring chips are used in stress concentration fields, then measurement relevance is improved, but adherence stability deteriorates due to high stress and noise interference
Solution Approach 1:
The patent replaces traditional mechanical adherence methods with a semiconductor integration approach, where strain measurement elements are fabricated and mounted within a semiconductor substrate. This substitution provides superior adherence stability in high-stress environments while maintaining measurement relevance through the substrate's mechanical coupling to the test object.
Solution Approach 2:
The patent employs composite material structures within the semiconductor substrate, combining different material layers and compositions to provide both high measurement sensitivity in stress concentration fields and enhanced adherence stability through the composite structure's superior mechanical properties.
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 enables precise measurement of torque, axial force, and multiaxial strain with reduced noise interference and adherence errors, allowing for accurate strain detection even in noisy environments and stress concentration fields.
Implementation Method 1
a resistance value of the metallic foil changes by a strain
Implementation Method 2
a strain gauge in which a metallic foil resistor having sensitivity for strain and a wheatstone bridge circuit for performing temperature compensation is formed on the same substrate
Data Source
AI summary
A mechanical-quantity measuring device capable of measuring a strain component in a specific direction with high precision is provided.At least two or more pairs of bridge circuits are formed inside a semiconductor monocrystal substrate and a semiconductor chip, and one of these bridge circuits forms a n-type diffusion resistor in which a direction of a current flow and measuring variation of a resistor value are in parallel with a <100> direction of the semiconductor monocryastal silicon substrate, and an another bridge circuit is composed of combination of p-type diffusion resistors in parallel with a <110> direction.