Phosphor Mixture for Stable Color Rendering in Streetlamps
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Solution Overview
Problem
Existing white light-emitting diodes for street lighting lack high color rendering index stability across varying temperatures and environmental conditions, and require flexibility in color temperature, while also needing high aging stability and efficiency.
Innovation Solution
A phosphor mixture comprising a first phosphor with a yellowish-green emission spectrum and a second phosphor with an orange-red emission spectrum, optimized for use with blue light excitation, providing a color temperature range of 3000 K to 6500 K and a color rendering index of at least 70, with high stability and resistance to temperature, radiation, and moisture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a phosphor mixture is designed to achieve high color rendering index (CRI ≥ 70) across a wide color temperature range (3000 K to 6500 K), then the color rendering performance is improved, but the stability of color point and brightness under varying temperatures becomes difficult to maintain
Solution Approach 1:
The patent employs a composite phosphor mixture comprising multiple phosphor materials with complementary emission characteristics. Specifically, it combines a first phosphor (yellowish-green emission, 540-560 nm peak) with a second phosphor (orange-red emission, 600-620 nm peak) in optimized ratios. This composite approach enables the mixture to maintain high color rendering index (≥70) across the entire color temperature range (3000-6500 K) while simultaneously ensuring color point stability, as each phosphor component compensates for the temperature-dependent shifts of the others.
Solution Approach 2:
The patent utilizes phosphor materials with specific emission wavelength parameters that are optimized for temperature stability. The first phosphor has its intensity maximum at 540-560 nm and the second at 600-620 nm, with both exhibiting minimal shift in peak wavelength across the operating temperature range. This parameter optimization ensures that the overall color point remains stable even as color temperature varies from 3000 K to 6500 K.
2Use of energy by moving object
If the phosphor mixture uses blue light excitation to achieve high system efficiency, then energy conversion efficiency is improved, but the resistance to environmental influences such as moisture and temperature fluctuations becomes more critical
Solution Approach 1:
The patent employs a composite phosphor mixture comprising multiple phosphor materials with complementary emission characteristics. Specifically, it combines a first phosphor (yellowish-green emission, 540-560 nm peak) with a second phosphor (orange-red emission, 600-620 nm peak) in optimized ratios. This composite approach enables the mixture to maintain high color rendering index (≥70) across the entire color temperature range (3000-6500 K) while simultaneously ensuring color point stability, as each phosphor component compensates for the temperature-dependent shifts of the others.
Solution Approach 2:
The patent utilizes phosphor materials with specific emission wavelength parameters that are optimized for temperature stability. The first phosphor has its intensity maximum at 540-560 nm and the second at 600-620 nm, with both exhibiting minimal shift in peak wavelength across the operating temperature range. This parameter optimization ensures that the overall color point remains stable even as color temperature varies from 3000 K to 6500 K.
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 a high color rendering index and stability across a wide temperature range, enhancing the performance of white light-emitting diodes in street lighting applications by maintaining brightness and color consistency under varying conditions.
Implementation Method 1
the first phosphor converts a portion of the incident light in a first wavelength range, in particular blue light, into light in a second wavelength range, in particular yellowish-green light
Implementation Method 2
the second phosphor converts another portion of the incident light in the first wavelength range into light in a third wavelength range, in particular orange-red light
Data Source
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AI summary
The invention relates to a luminescent-substance mixture, comprising a first luminescent substance (1) and a second luminescent substance (2). When the luminescent-substance mixture is excited with blue light, the emission spectrum of the first luminescent substance (1) has a relative intensity maximum in the yellow-green spectral range at a wavelength of greater than or equal to 540 nm and less than or equal to 560 nm and the emission spectrum of the second luminescent substance (2) has a relative intensity maximum in the orange-red spectral range at a wavelength of greater than or equal to 600 nm and less than or equal to 620 nm. The invention further relates to a light-emitting semiconductor component and to a streetlamp having a luminescent-substance mixture.