Wavelength Conversion Element Stabilizing Color Locus Across Temperature
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Solution Overview
Problem
Conversion elements used in lighting systems experience shifts in color locus and correlated color temperature due to temperature changes, leading to undesirable changes in light color perception as they generate waste heat, which existing solutions fail to adequately stabilize.
Innovation Solution
A conversion element comprising a temperature-dependent matrix material and multiple types of luminophore particles with specific refractive index and emission wavelength properties, optimized to maintain a stable color locus and correlated color temperature across a wide temperature range by balancing scattering and emission effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a conversion element is used to convert blue light to other wavelengths, then light conversion efficiency is improved, but color locus stability deteriorates due to temperature changes
Solution Approach 1:
The patent applies parameter changes by selecting luminophore particles with specific emission wavelengths and the matrix material with a particular refractive index temperature coefficient. By carefully choosing these parameters - the emission wavelengths of green and red luminophores and the refractive index temperature dependence of the matrix material - the patent achieves compensation of temperature-induced color shifts while maintaining high conversion efficiency
Solution Approach 2:
The patent uses a composite material system consisting of multiple types of luminophore particles (green-emitting and red-emitting) embedded in a matrix material with specific optical properties. This composite structure enables the conversion element to simultaneously achieve high light conversion efficiency and stable color locus by combining the wavelength conversion capabilities of different luminophores with the temperature-compensating optical properties of the matrix material
2Stability of the object's composition
If the matrix material has a temperature-dependent refractive index, then color locus stability is improved, but manufacturing precision deteriorates
Solution Approach 1:
The patent specifies precise parameter ranges for the matrix material's refractive index temperature coefficient and the luminophore particles' emission wavelengths. By defining these parameters within specific ranges, the patent achieves color locus stability while maintaining manufacturability through clear specification criteria that guide material selection and production processes
3Stability of the object's composition
If multiple types of luminophore particles are used, then color stability across temperature range is improved, but device complexity increases
Solution Approach 1:
The patent employs a composite material approach by combining green-emitting and red-emitting luminophore particles in a matrix material with specific optical properties. This composite structure achieves color stability across temperature ranges through the complementary temperature dependencies of different luminophores, while the complexity is managed by integrating these components into a single monolithic conversion element rather than separate modules
Solution Approach 2:
The patent merges multiple luminophore types with different emission characteristics into a single conversion element structure. By combining green and red luminophores in one matrix material body, the patent achieves color stability through their complementary temperature responses while simplifying the overall device architecture compared to using separate conversion layers or components
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 ensures that the color temperature and locus of the emitted light remain substantially constant between 25°C and 150°C, preventing perceptible changes in light color even with temperature fluctuations, thus providing stable lighting performance.
Implementation Method 1
The matrix material has an optical refractive index that is temperature-dependent. In particular, the refractive index is temperature-dependent in a temperature range of approximately 20° C. to approximately 200° C.
Implementation Method 2
the conversion element converts at least part of a primary radiation, for example blue light, to a secondary radiation, for example red, green and/or yellow light
Implementation Method 3
optimzed to maintain a stable color locus and correlated color temperature across a wide temperature range by balancing scattering and emission effects
Data Source
AI summary
A conversion element for the wavelength conversion of electromagnetic radiation from a first wavelength range to electromagnetic radiation from a second wavelength range, which includes longer wavelengths than the first wavelength range, the conversion element includes: a matrix material, the optical refractive index of which is temperature-dependent, and at least two different types of luminophore particles wherein a multiplicity of luminophore particles of each of the types are distributed in the matrix material, luminophore particles of different types differ from one another in terms of average particle size and/or material, the conversion element, upon excitation by electromagnetic radiation from the first wavelength range emits mixed radiation including electromagnetic radiation from the first and the second wavelength range, and the correlated color temperature and/or the color locus of the mixed radiation remain(s) substantially the same when the matrix material is at a temperature of between 25° C. and 150° C.