Composite Phosphor Materials for Display Color Gamut and Cost Reduction
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Solution Overview
Problem
Existing phosphor materials for emitting visible light under optical excitation are limited in their ability to produce a wide range of colors, particularly red light, due to the high cost and limited availability of certain transition metal compounds, which restricts the color gamut and brightness in display applications.
Innovation Solution
A composite phosphor material is developed by mixing red-emitting nitride phosphors with orange-red emitting silicate phosphors, optimizing the emission wavelength to achieve desired colors while reducing the cost and maintaining thermal quenching performance, using a combination of (Ba,Sr,Ca)AlSiN3:Eu, (Ca,Sr,Ba) Si2O2N2:Eu, and (Ca,Sr,Ba)2Si5N8:Eu for red emission and (Sr,Ba,Ca)2SiO4:Eu for green emission, along with Sr3MgSi2O8:Eu for blue emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If red-emitting nitride phosphors are used to achieve desired color emission, then color gamut and brightness are improved, but cost increases due to high cost and limited availability of certain transition metal compounds
Solution Approach 1:
The patent applies composite phosphor materials combining red-emitting nitride phosphors with orange-red emitting silicate phosphors. This composite approach allows the system to achieve the desired color gamut and brightness through the synergistic effect of multiple phosphor materials, while reducing dependence on expensive and limited transition metal compounds by substituting part of the red phosphor with cheaper orange-red phosphor.
Solution Approach 2:
The patent optimizes the emission wavelength and composition ratios of the composite phosphor materials. By adjusting the parameters such as the ratio of red to orange-red phosphors and optimizing emission wavelengths, the system achieves the desired color properties while minimizing cost through reduced use of expensive materials.
2Adaptability or versatility
If red-emitting nitride phosphors are used to expand color gamut, then color reproduction is improved, but availability of materials deteriorates due to limited availability of certain transition metal compounds
Solution Approach 1:
The patent uses composite phosphor materials that combine red-emitting nitride phosphors with orange-red emitting silicate phosphors. This composite structure expands the color gamut by utilizing the spectral characteristics of both phosphor types, while simultaneously reducing the demand for limited transition metal compounds by substituting orange-red silicate phosphor for some of the red nitride phosphor.
3Ease of manufacture
If composite phosphor material mixing red and orange-red phosphors is used, then cost is reduced by using less expensive silicate phosphors, but manufacturing precision must be optimized to achieve desired color
Solution Approach 1:
The patent optimizes the emission wavelength and composition ratios of the composite phosphor materials. By carefully adjusting the ratio of red to orange-red phosphors and selecting specific emission wavelengths, the system achieves the desired color properties while minimizing cost through reduced use of expensive materials.
Solution Approach 2:
The patent provides flexibility in the composition ratios of the composite phosphor materials, allowing optimization of both cost and color accuracy based on specific application requirements. This dynamic approach enables manufacturers to adjust the formulation to balance material cost against manufacturing precision needs.
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 composite phosphor material enhances color reproduction, reduces costs by using less expensive silicate phosphors, and maintains high thermal quenching performance, improving brightness and color accuracy in display systems while adhering to NTSC/PAL color gamut requirements.
Implementation Method 1
phosphor materials which absorb excitation light to emit visible light
Implementation Method 2
absorb excitation light at a given excitation wavelength
Implementation Method 3
the composite phosphor material having reduced thermal quenching
Data Source
AI summary
Techniques and optically excited light-emitting devices based on phosphors are provided to use phosphor materials which absorb excitation light to emit visible light and include a composite phosphor material including two or more different transition metal compounds that, under optical excitation of the excitation light, emit visible light at spectrally close but different spectral wavelengths or bands that spectrally overlap to produce a desired color.