Force Sensor Using Thin Insulating Film for Temperature Stability
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Solution Overview
Problem
Existing force measurement technologies face challenges in achieving high-resolution, temperature-stable, and miniaturized designs without deformation, particularly in the millinewton to meganewton range, and struggle with temperature-dependent drift in piezoresistive layers.
Innovation Solution
A device using thin insulating films, such as zinc oxide or diamond-like carbon, between metal electrodes to measure force with minimal deformation, incorporating a reference electrode for temperature compensation, allowing for high-resolution and continuous force measurement across a wide temperature range, and enabling flexible geometric configurations for various applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If piezoresistive layers are used for force measurement, then sensitivity to force is improved, but temperature-dependent drift occurs
Solution Approach 1:
The patent changes the material parameter from piezoresistive material to thin insulating film material, fundamentally altering the measurement mechanism from resistance change to capacitance change, thereby eliminating temperature-dependent drift while maintaining force measurement sensitivity
Solution Approach 2:
The patent substitutes the electrical resistance-based measurement system with a capacitance-based measurement system using insulating films, replacing the piezoresistive effect with electrostatic field effects that are not subject to temperature-dependent drift
2Force
If deformation bodies are used in force sensors, then mechanical force transmission is achieved, but sensor design complexity increases
Solution Approach 1:
The patent extracts and removes the deformation body from the sensor design, using only rigid mechanical force transmission elements combined with thin insulating films, thereby simplifying the overall sensor design while maintaining force transmission capability
Solution Approach 2:
The patent introduces thin insulating films as intermediary elements between rigid force transmission components, enabling capacitance-based measurement without requiring the components themselves to deform
3Volume of moving object
If miniaturized sensor design is implemented, then installation space is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The patent employs thin insulating films as the core sensing element, utilizing modern thin-film deposition techniques that can precisely control film thickness at the micrometer and sub-micrometer scale, enabling miniaturization without sacrificing manufacturing precision
Solution Approach 2:
The patent uses composite structures combining rigid force transmission elements with thin insulating films, where the insulating films provide the sensing function with precise thickness control through deposition processes, while the rigid components handle mechanical loading
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 robust, temperature-independent, and high-resolution force measurement system with minimal deformation, capable of operating from -80°C to 1200°C, suitable for both miniaturized and large-scale applications, with enhanced mechanical and chemical robustness, and the ability to detect forces in multiple dimensions.
Implementation Method 1
The piezoresistive effect describes a change in the electrical resistance of a material as a result of the application of a high external force or pressure
Implementation Method 2
the electrical conductivity of which describes an unambiguous and exactly traceable function of the acting force
Data Source
AI summary
A device for electrically measuring a force includes a load cell having a first metal electrode and a second metal electrode disposed opposite thereof in the direction of the force, each having contact surfaces in which the force to be measured can be impressed, and electrical resistance in the range of a few milliohms to less than or equal to ten ohms and a mean roughness value (Ra) of less than or equal to 400 nanometers, for forming force-independent conductivity, a thin insulating film disposed between the first and second metal electrodes in a form-locked manner, a reference metal electrode disposed on a section of the thin insulating film such that it is force-decoupled from the first metal electrode and tensioned with respect to the second metal electrode at a constant retaining force by a fastening element, and a measuring circuit designed as a half bridge or a full bridge.