Laser-Excited White Light Source With Ce-Garnet for High CRI
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Solution Overview
Problem
Existing white LED sources face challenges in achieving high intensity with high color rendering index (CRI) and low correlated color temperature (CCT), as phosphors often cannot withstand high pump powers and exhibit thermal quenching, leading to degradation.
Innovation Solution
A light generating device comprising a blue laser light source, a red laser light source, and a cerium-doped garnet luminescent material that converts blue light into green and yellow emissions, with the red light source contributing to achieve a high CRI and adjustable CCT within the range of 2000-3150 K.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If phosphor materials are used in traditional LED sources to generate white light, then the device can provide illumination, but the phosphors cannot withstand high pump powers and exhibit thermal quenching leading to degradation
Solution Approach 1:
The patent extracts the problematic phosphor material from the system and replaces it with a laser diode light source operating at 450-470 nm that directly excites the down-conversion layer, eliminating thermal quenching and degradation issues associated with traditional phosphors under high pump power conditions
Solution Approach 2:
The patent changes the operational parameters by using a laser diode with specific wavelength range (450-470 nm) and controlling the down-conversion layer thickness (1-100 μm) to optimize light conversion efficiency while maintaining reliability under high power operation, avoiding the thermal quenching phenomenon
2Illumination intensity
If traditional phosphor-based LED sources are used, then the structure is simple, but achieving high intensity with high CRI and low CCT is difficult
Solution Approach 1:
The patent segments the lighting system into distinct functional layers: a laser diode light source layer emitting at 450-470 nm, and a separate down-conversion layer with specific thickness (1-100 μm), allowing independent optimization of each component to achieve high intensity and high CRI while maintaining a relatively simple overall structure
Solution Approach 2:
The patent employs composite material structure combining a laser diode material with specific wavelength characteristics and a down-conversion layer material, creating a hybrid system that achieves high illumination intensity and high color rendering index (CRI ≥ 80) while controlling correlated color temperature (CCT: 2000-3150 K)
3Productivity
If high pump power is applied to phosphor materials, then light output intensity increases, but thermal quenching occurs causing degradation
Solution Approach 1:
The patent converts the potential harmful effect of high pump power by using a laser diode that operates efficiently at high power levels without thermal quenching, transforming the high energy input into beneficial high-intensity light output with CRI ≥ 80 and adjustable CCT, while the controlled down-conversion layer thickness (1-100 μm) prevents any residual thermal effects
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 device provides high-intensity white light with a CRI of at least 75, preferably 85, and a CCT of 2400-3000 K, effectively overcoming the limitations of thermal quenching and degradation in traditional phosphor-based systems.
Implementation Method 1
a cerium-doped garnet luminescent material that converts blue light into green and yellow emissions
Data Source
Figure 1~2A
Figure 2B~2C
Figure 2D~3
AI summary
The invention provides a light generating device (1000) configured to generate device light (1001), wherein the light generating device (1000) comprises a first light source (110), a first luminescent material (210), a second light source (120) of second light source light (121), and a second light source (130), wherein: the first light source (110) is configured to generate blue first light source light (111) having a first peak wavelength λ1 selected from the spectral wavelength range of 437- 472 nm, wherein the first light source (110) is a first laser light source (10); the first luminescent material (210) is configured to convert at least part of the first light source light (111) into first luminescent material light (211) having an emission band having wavelengths in one or more of (a) the green spectral wavelength range and (b) the yellow spectral wavelength range, wherein the first luminescent material (210) comprises a luminescent material of the type A3B5O12:Ce, wherein A comprises one or more of Y, La, Gd, Tb and Lu, especially (at least) one or more of Y, Gd, Tb and Lu, and wherein B comprises one or more of Al, Ga, In and Sc; the second light source (120) of second light source light (121) is configured to provide the second light source light (121) having an emission band having a dominant wavelength or peak wavelength in the spectral wavelength range of 580-610 nm; the second light source (130) is configured to generate red second light source light (131) having a second peak wavelength λ3 selected from the spectral wavelength range of 630-670 nm, wherein the second light source (130) is a second laser light source (30); the light generating device (1000) is configured to provide in a first operational mode white device light (1001) comprising the first light source light (111), the first luminescent material light (211), the second light source light (121), and the second light source light (131), with a correlated color temperature selected from the range of 2000-3150 K and a color rendering index (CRI) of at least 80.