Two-Dye Fluorescence Thermography for Plastic Packaging
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Solution Overview
Problem
Infrared thermography is limited by high costs and incompatibility with inexpensive materials like plastics, making it less suitable for actively cooled applications and requiring expensive equipment for high frame rates.
Innovation Solution
An optical thermography system using a pumped two-dye fluorescence technique with a base member having temperature and fluorescent solution channels, allowing for visible light thermography that is cost-effective and compatible with plastics, with a test sample surface above the channels, and utilizing two fluorophores to reduce errors from light fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If infrared thermography is used to achieve high frame rates, then temporal resolution is improved, but equipment cost increases significantly
Solution Approach 1:
The patent replaces expensive infrared detection systems with a visible light fluorescence-based optical system. By using fluorescent dyes that emit visible light in response to temperature changes, the system achieves high frame rate thermography using standard optical cameras instead of costly infrared equipment, directly resolving the contradiction between temporal resolution and equipment cost
Solution Approach 2:
The patent changes the detection parameter from infrared radiation detection to visible light fluorescence detection. This parameter change allows the use of conventional optical cameras with high frame rates, eliminating the need for expensive specialized infrared equipment while maintaining high temporal resolution for thermography applications
2Measurement precision
If infrared thermography is used, then temperature measurement capability is achieved, but compatibility with plastics and inexpensive materials is lost
Solution Approach 1:
The patent substitutes infrared detection with visible light fluorescence detection, which is not constrained by material transparency requirements. This allows temperature measurement on plastics and inexpensive materials that are opaque to infrared radiation but can support fluorescent dye attachment, significantly improving material compatibility while maintaining temperature measurement precision
Solution Approach 2:
The patent introduces fluorescent dyes as intermediary substances that mediate between the target surface and the detection system. These dyes can be applied to various materials including plastics, and they convert temperature information into visible light signals, enabling temperature measurement on materials that would be incompatible with direct infrared thermography
3Device complexity
If single-dye fluorescence technique is used, then system simplicity is maintained, but measurement accuracy deteriorates due to light fluctuations
Solution Approach 1:
The patent extracts and separates the temperature-dependent fluorescence signal from the light intensity fluctuation signal by using two different dyes with distinct spectral characteristics. One dye's fluorescence is primarily temperature-dependent while the other serves as a reference for light fluctuations, allowing the system to eliminate measurement errors while maintaining relative system simplicity
Solution Approach 2:
The patent changes from a single fluorescence parameter to a dual-fluorescence parameter system. By monitoring the ratio or difference between two dye fluorescence signals with different temperature dependencies and excitation/emission characteristics, the system can distinguish temperature-induced changes from light source fluctuations, improving measurement accuracy without significantly increasing system complexity
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 system achieves high sensitivity and repeatability in temperature measurements with reduced photobleaching effects, enabling local heat flux and temperature data collection with high spatial and temporal resolutions, and is compatible with actively cooled applications.
Implementation Method 1
A fluorescent solution is flowed through the fluorescent solution channel. The fluorescent solution has an absorption band at a first wavelength and an emission band at a second wavelength
Implementation Method 2
A temperature regulating fluid is flowed through the temperature regulating fluid channel
Implementation Method 3
utilizing two fluorophores to reduce errors from light fluctuations and reduced photobleaching effects
Data Source
AI summary
A backside thermography technique was developed based on the temperature sensitivity of laser-induced fluorescence in flowing two-dye solutions. The approach utilizes visible light and optically transparent packaging materials to obtain spatially resolved transient thermal measurements. This technique is compatible with optically transparent water-cooled packaging, which will allow for the characterization of processes where heat is added as well as removed. A setup was designed, constructed, and used to study the performance of seven two-dye Rhodamine B (RhB)-Rhodamine 110 (Rh110) fluorescent solutions. The effect of dye concentration ratio on sensitivity, maximum frame rate, and excitation area was characterized. The system was used to demonstrate in-situ temperature measurements showing the importance of two-dye light compensation, as well as backside thermography using a simple droplet contact method to investigate temporal response. Droplet contact experiments were conducted on actively heated and cooled surfaces to study local temperature and heat flux behavior during phase change.