Strain Sensor with Color Emission via Phosphor Conversion
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Solution Overview
Problem
Current strain sensors lack the ability to effectively indicate strain with red color emission, which is crucial for safety-related and biomedical applications, and there is a limited capability to convert green emission to red emission within the inorganic phosphor group.
Innovation Solution
A strain sensor with a mechano-luminescent layer comprising green emissive particles and red emissive particles, where the green emissive particles emit green light due to external force or pressure, and the red emissive particles absorb and convert this green emission to red emission, using a polymer matrix and conductive fillers, including ZnS:Cu and rhodamine B-coated silica particles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If ZnS:Cu is mixed with elastic material PDMS to realize friction organic electroluminescence, then displacement sensing capability is improved, but red color emission is not achieved
Solution Approach 1:
The patent combines ZnS:Cu green emissive particles with red phosphor particles in a PDMS matrix to create a composite mechano-luminescent material that simultaneously achieves displacement sensing capability and red color emission through the composite effect of different phosphor materials
Solution Approach 2:
The patent modifies the emission color parameter by introducing red phosphor particles that convert the green emission from ZnS:Cu to red emission, thereby changing the output light parameter while maintaining the displacement sensing mechanism
2Measurement precision
If conventional trap emission mechano-luminance mechanism is used with rigid matrix materials, then stress sensing is achieved, but UV activation is required and displacement measurement capability is limited
Solution Approach 1:
The patent replaces the conventional trap emission mechanism requiring UV activation with a friction organic electroluminescence mechanism that is directly activated by mechanical displacement, eliminating the need for UV activation while maintaining stress sensing capability
Solution Approach 2:
The mechano-luminescent material performs self-activation through friction organic electroluminescence generated by displacement itself, without requiring external UV activation, making the system self-sufficient and easier to operate
3Illumination intensity
If red emissive particles are added to convert green emission to red emission, then red color emission is achieved, but device complexity increases
Solution Approach 1:
The patent merges the green emissive ZnS:Cu particles and red phosphor particles into a single integrated mechano-luminescent layer within the PDMS matrix, combining multiple functions (displacement sensing and red emission) in one component rather than separate systems
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 sensor achieves red color emission proportional to strain rate, enhancing visual warning effectiveness for safety and biomedical applications by combining piezoresistive and mechano-luminescent layers with a polymer matrix, allowing for precise strain measurement and visualization.
Implementation Method 1
light emission resulting from displacement in a different manner from conventional methods such as friction organic electroluminescence is generated at a high luminance
Implementation Method 2
red emissive particles configured to absorb the green emission from the green emissive particles, to convert the absorbed green emission to red emission
Implementation Method 3
a piezoresistive layer configured to have varying electrical resistance according to a displacement due to external force or pressure applied thereto
Data Source
AI summary
A strain sensor with color emission indicating a strain is disclosed. The strain sensor can include a piezoresistive layer having a first portion of a polymer matrix body and conductive fillers dispersed in the first portion of the polymer matrix body, a mechano-luminescent layer having a second portion, which is disposed on the first portion, of the polymer matrix body, green emissive particles, and red emissive particles, the green and red emissive particles being dispersed in the second portion of the polymer matrix body, and a first and second electrodes spaced apart from each other and directly connected to the piezoresistive layer.