Phosphor Mixture for Warm-White Light with Thermal Stability
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Solution Overview
Problem
There is a need for a phosphor mixture that can generate warm-white light efficiently and maintain stability at high temperatures, suitable for use in optoelectronic components and street lamps.
Innovation Solution
A phosphor mixture comprising a first phosphor with a yellow emission spectrum and a second phosphor with a red emission spectrum, both specifically formulated as (LuxY1−x)(Al1−y)Gay)5O12:Ce3+, where x and y are within defined ranges, to convert blue light into yellow and red light, respectively, while maintaining stability and efficiency under thermal loading.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If conventional phosphor mixtures are used to generate warm-white light, then light output is achieved, but lifetime is reduced and efficiency drops at high temperatures
Solution Approach 1:
The patent employs a composite phosphor mixture comprising multiple phosphor materials with distinct emission characteristics. Specifically, it combines a first phosphor (Y3Al5O12:Ce3+) emitting in the yellow-green range with a second phosphor emitting in the red range. This composite structure allows the system to maintain stable light output and color temperature across wide temperature ranges, while extending operational lifetime by preventing individual phosphor degradation that would occur in single-phosphor systems.
2Use of energy by moving object
If phosphor mixtures are used for warm-white light generation, then light output is produced, but efficiency decreases due to quenching behavior at high temperatures
Solution Approach 1:
The patent optimizes the emission wavelength parameters of the constituent phosphors to minimize thermal quenching. The first phosphor is selected with peak emission in the yellow-green range (540-570 nm) and the second phosphor in the red range (610-650 nm). This parameter selection ensures that the phosphors operate in wavelength regions less susceptible to thermal quenching effects, thereby maintaining high conversion efficiency even under significant thermal loading conditions.
3Ease of manufacture
If simple phosphor formulations are used, then manufacturing is easier, but color rendering index and temperature stability are insufficient
Solution Approach 1:
The patent assigns specific functional roles to different phosphor components based on their local emission characteristics. The first phosphor (Y3Al5O12:Ce3+) is specifically chosen for its yellow-green emission to provide the dominant warm-white component, while the second phosphor is selected for its red emission to fill spectral gaps and improve color rendering. This localized functional assignment allows each component to be optimized for its specific role, achieving high color rendering index (Ra > 90) and temperature stability without requiring complex multi-component formulations.
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 phosphor mixture achieves high color rendering index and temperature stability, ensuring efficient warm-white light generation with minimal quenching behavior, making it suitable for long-term use in optoelectronic components and street lamps.
Implementation Method 1
the phosphor mixture including a first phosphor and a second phosphor, wherein an emission spectrum of the first phosphor has a relative intensity maximum in a yellow spectral range and an emission spectrum of the second phosphor has a relative intensity maximum in a red spectral range... which converts at least part of radiation of a first wavelength range emitted by the semiconductor body into radiation of a second wavelength range different from the first wavelength range, and into radiation of a third wavelength range different from the first and second wavelength ranges
Data Source
AI summary
A phosphor mixture includes a first phosphor and a second phosphor, wherein an emission spectrum of the first phosphor has a relative intensity maximum in a yellow spectral range and an emission spectrum of the second phosphor has a relative intensity maximum in a red spectral range, the first phosphor corresponds to the following chemical formula: (LuxY1−x)3(Al1−yGay)5O12:Ce3+, where x is greater than or equal to 0 and less than or equal to 1 and where y is greater than or equal to 0 and less than or equal to 0.4, and the phosphor mixture is formed from a plurality of particles, which includes a plurality of particles of the first phosphor and a plurality of particles of the second phosphor.