Laser-Pumped Light Source with Dual Emission for Spectral Stability
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Solution Overview
Problem
Existing high-power density light sources using laser pumps and pumped luminescent crystals face issues with spectral properties changing over time and with temperature, leading to undesirable variations in light output.
Innovation Solution
A light generating system comprising a first light generating device, a first luminescent material with line absorber and emitter, and a second luminescent material with broad band emission, configured to generate high CRI, high intensity, and spectrally stable light by controlling color point and correlated color temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If laser pumps and pumped luminescent crystals are used to achieve high brightness, then intensity can reach up to 20,000 lm/mm², but spectral properties change over time and with temperature
Solution Approach 1:
The patent combines two different luminescent materials with complementary spectral characteristics - a first material (e.g., YAG:Ce) that emits in one spectral region and a second material (e.g., nitride phosphor) that emits in another spectral region. This merging of materials creates a composite phosphor layer that maintains spectral stability over time and temperature while achieving high brightness through laser pumping.
Solution Approach 2:
The invention uses composite phosphor materials consisting of multiple luminescent compounds with different emission characteristics. This composite approach allows the system to maintain stable spectral properties because when one material's emission shifts with temperature or aging, the other material compensates, maintaining overall spectral stability while achieving high intensity output.
2Power
If high-power density laser pumping is applied to luminescent crystals, then high intensity light is generated, but heat management becomes problematic
Solution Approach 1:
The patent applies different luminescent materials with varying thermal properties to different regions or layers within the phosphor conversion element. This allows optimal thermal management in each layer - materials with higher thermal conductivity can be positioned in regions experiencing higher heat loads, while materials with better optical properties are placed in regions prioritizing light conversion efficiency.
3Stability of the object's composition
If spectral properties are optimized for high CRI, then color rendering improves, but intensity may be reduced
Solution Approach 1:
The patent designs a multi-layer phosphor system where each layer performs multiple functions: the first luminescent material provides both high intensity output and partial color rendering, while the second luminescent material supplements the spectral output to improve CRI. This multi-functional design allows the system to simultaneously achieve high intensity and good color rendering that would be difficult with a single material.
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 system provides high-intensity, spectrally stable light with improved reliability and controlled color properties, reducing spectral variations over time and temperature.
Implementation Method 1
the first luminescent material is configured to convert light at a first wavelength to light at a second wavelength
Implementation Method 2
laser provides laser light and e.g. a (remote) phosphor converts laser light into converted light
Implementation Method 3
a first luminescent material with line absorber and emitter, and a second luminescent material with broad band emission
Data Source
AI summary
The invention provides in embodiments a light generating system (1000) comprising a first light generating device (100), a first luminescent material (210), and a second luminescent material (220), wherein: A) the first light generating device (110) is configured to generate first device light (111), wherein the first light generating device (110) comprises a first light source (10) selected from the group of a superluminescent diode and a laser; B) the first luminescent material (210) comprises a line absorber and line emitter luminescent material providing a first luminescent material emission (211) comprising a line emission at a first wavelength (λL,1) upon excitation with the first device light (111); C) the second luminescent material (220) comprises a broad band emitter luminescent material providing a second luminescent material emission (221) comprising a broad band emission upon excitation with the first device light (111), wherein the second luminescent material emission (221) has a second centroid wavelength (λLC,2), wherein |λL,1-λLC,2|≤20 nm; D) the first light generating device (110) is configured to pump one or more of the first luminescent material (210) and the second luminescent material (220) with the first device light (111); and E) the light generating system (1000) is configured to generate system light (1001) comprising one or more of the first luminescent material emission (211) and the second luminescent material emission (221).