Smart Optical Materials for Phosphor Hiding and Thermal Stability
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Solution Overview
Problem
Existing optical materials fail to effectively hide wavelength converters like phosphors in off-state optical devices while maintaining high light transmittance efficiency and resistance to thermal aging, as they either remain hazy or require camouflage, which compromises cracking resistance and aesthetic appeal.
Innovation Solution
Development of smart optical materials with a thermo-optical matrix and treated athermo-optical filler, which are opaque at room temperature but transparent at elevated temperatures, ensuring good light transmittance and resistance to thermal aging, and are designed to hide wavelength converters without altering the binder's color or cracking resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If refractive index matching is used to maximize transparency, then light transmittance efficiency is improved, but the ability to hide wavelength converters in off-state is lost
Solution Approach 1:
The optical material transitions from opaque at room temperature to transparent at elevated temperatures, dynamically changing its optical properties based on operating conditions. This allows the material to hide wavelength converters during off-state while maintaining high light transmittance efficiency during on-state operation.
Solution Approach 2:
The material's refractive index and optical transparency are changed as a function of temperature. At room temperature, the material exhibits opaque characteristics to hide phosphors, while at operating temperatures, it becomes transparent to maximize light output, thus resolving the contradiction between hiding wavelength converters and maintaining light transmittance efficiency.
2Loss of information
If hazy or cloudy materials are used to hide phosphors, then off-state appearance is improved, but light transmittance efficiency and cracking resistance deteriorate
Solution Approach 1:
The material dynamically transitions from hazy/opaque to clear/transparent based on temperature, allowing it to provide phosphor hiding capability when needed while maintaining excellent light transmittance efficiency during operation, thus avoiding the permanent degradation associated with traditional hazy materials.
Solution Approach 2:
The optical properties of the material are changed as a function of temperature, allowing it to exhibit opaque characteristics at room temperature for aesthetic purposes while becoming transparent at operating temperatures to maximize light output, thereby resolving the contradiction between off-state appearance and on-state performance.
3Loss of information
If untreated filler is used to provide opacity, then off-state hiding capability is improved, but cracking resistance and light transmittance after thermal aging deteriorate
Solution Approach 1:
The material uses temperature-dependent parameter changes to achieve opacity at room temperature and transparency at elevated temperatures, providing phosphor hiding capability without the need for untreated filler that would compromise cracking resistance and reliability after thermal aging.
Solution Approach 2:
The invention uses a composite material system with specific refractive index matching and temperature-dependent optical properties that provides both aesthetic appearance and structural reliability, avoiding the use of untreated filler that would degrade performance after thermal aging while maintaining the ability to hide wavelength converters in off-state.
4Loss of information
If camouflage techniques are used to hide phosphors, then off-state appearance is improved, but cracking resistance deteriorates
Solution Approach 1:
The material uses dynamic temperature-dependent optical changes to achieve phosphor hiding capability without relying on camouflage techniques that compromise cracking resistance. The material transitions from opaque to transparent based on temperature, providing aesthetic appearance while maintaining structural strength.
Solution Approach 2:
The optical parameters of the material are changed as a function of temperature to achieve the desired aesthetic appearance in off-state while maintaining the binder's color and cracking resistance properties, thus resolving the contradiction between appearance and structural integrity.
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 smart optical materials achieve enhanced light output and transmittance efficiency when powered on, maintain mechanical integrity, and provide an aesthetically pleasing appearance by being opaque at room temperature and transparent at elevated temperatures, while resisting cracking and maintaining high elongation-at-break values after thermal aging.
Implementation Method 1
the smart optical material is opaque according to the Opaqueness Test Method 1 at a temperature less than 30° C. and optically transparent at a temperature of from 80° to 200° C.
Implementation Method 2
the smart optical material provides an aesthetically pleasing appearance by being opaque at room temperature and transparent at elevated temperatures, while resisting cracking and maintaining high elongation-at-break values after thermal aging.
Data Source
Figure 1
AI summary
A smart optical material characterized in that when the material is at ambient temperature (≤ 30° C), it is opaque to at least one color light in the visible light spectrum and when the material is at an elevated temperature of at least 80° C, it is substantially transparent to the at least one color light. The smart optical material is also characterized as having before thermal aging an elongation-at-break of at least 15% and after thermal aging in air at 200° C for seven days an elongation-at-break that is unchanged or is at least 12% and has decreased by from > 0% to less than 50%. Also included are related formulations, methods, uses, articles and devices.