Monolithic Force Sensor Package With Temperature Compensation
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Solution Overview
Problem
Conventional force sensors face challenges in accurately measuring applied forces due to difficulties in mounting sensor elements, asymmetry leading to measurement errors, and temperature-induced strain from differing thermal expansion coefficients, which introduce errors in force measurement.
Innovation Solution
A force sensor package with a monolithic integrated circuit design that includes a force sensor chip, temperature sensor, and processing circuitry for temperature compensation, combined with an integrated deformation body that generates different stress components in orthogonal directions, reducing the need for multiple sensor elements and simplifying mounting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional force sensors use multiple small sensor elements (strain gauges) to measure applied force, then measurement capability is provided, but mounting difficulty increases and measurement accuracy decreases due to asymmetry and thermal expansion differences
Solution Approach 1:
The patent merges multiple sensor elements into a single integrated force sensor package with a unified mounting interface. The sensor package integrates the sensing element, deformation body, and mounting structure into one component that attaches to the deformation body through a single mounting operation, eliminating the complexity of mounting multiple separate strain gauges while maintaining measurement accuracy through symmetric design
Solution Approach 2:
The sensor package serves multiple functions simultaneously: it provides force measurement capability, incorporates temperature compensation, and includes an integrated mounting structure. This multi-functional design eliminates the need for separate mounting operations for each functional component, reducing overall mounting complexity while maintaining measurement precision
2Temperature
If conventional force sensors use sensor elements with different coefficients of thermal expansion, then temperature sensing capability is provided, but measurement accuracy decreases due to thermally-induced strain
Solution Approach 1:
The patent introduces a temperature sensor as an intermediary element that measures temperature independently without introducing thermal expansion errors into the force measurement. The temperature sensor data is then used by processing circuitry to compensate for thermal effects on the force measurement, allowing both temperature sensing and accurate force measurement without the harmful thermal strain introduced by mismatched expansion coefficients
Solution Approach 2:
The system uses feedback from the temperature sensor to dynamically adjust the force measurement readings. The processing circuitry receives both force sensor output and temperature sensor output, then applies temperature compensation algorithms to correct for thermal effects, maintaining measurement accuracy across varying temperature conditions
3Stability of the object's composition
If conventional force sensors require careful material selection for sensor elements, then measurement stability is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The sensor package uses sensor elements and structural components made from materials with matched coefficients of thermal expansion, ensuring homogeneous thermal behavior across the assembly. This eliminates the need for complex material selection and matching processes, simplifying manufacturing while maintaining measurement stability through reduced thermal strain
Solution Approach 2:
The sensor package incorporates temperature compensation functionality within the package itself, using the temperature sensor and processing circuitry to automatically correct for thermal effects. This self-compensating design eliminates the need for external calibration and complex material matching, reducing manufacturing complexity while maintaining measurement stability
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 accurate force measurement by compensating for temperature-induced errors and simplifies the mounting process, reducing the number of sensor elements and manufacturing costs while improving installation ease and accuracy.
Implementation Method 1
the force sensor elements are configured to generate stress measurement signals representative of either in-plane shear stress (sigXY) or the difference of in-plane normal stress components (sigXX−sigYY)
Implementation Method 2
conventional force sensors are impacted by changes in temperature, as the various sensor components may have different coefficients of thermal expansion and thus expand at different rates
Data Source
AI summary
The described techniques are directed to a force sensor package that includes a force sensor and a temperature sensor combined in a monolithic integrated circuit. The force sensor package may also include other components, such as a memory and onboard processing circuitry (e.g. a microcontroller), which allows for temperature compensation to be performed on the force measurement signals generated by the force sensor. Force sensors are also described that include an integrated deformation body, such as a planar spring. Various types of deformation bodies are described, to which a force sensor chip is coupled. The structure and coupling between the force sensor chip and the deformation body facilitates the generation of stresses in two orthogonal directions in the force sensor chip having different values in response to an applied force.