Laser-Excited Phosphor Housing for Color-Uniform Light Output
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Solution Overview
Problem
Existing light emitting devices face challenges in achieving color uniformity and chromaticity flexibility due to saturation of fluorescent output from phosphors when excited with high-power density laser light, leading to decreased conversion efficiency and color irregularity.
Innovation Solution
A light emitting device design incorporating a laser light source, a housing with a reflecting bottom wall and side wall-mounted first wavelength converters containing phosphors, where the laser light is diffused by a light diffusing layer before exciting the phosphors, reducing power density and preventing saturation, and allowing for additive mixing of laser light and phosphor-emitted optical components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high power density laser light is used to excite the phosphor, then light output is improved, but conversion efficiency decreases due to saturation of fluorescent output
Solution Approach 1:
The invention divides the excitation process into two stages: first, laser light excites the phosphor to produce fluorescence; second, UV irradiation excites the fluorescent substance to produce additional light. This segmentation allows the system to achieve high light output without over-saturating the phosphor, maintaining conversion efficiency while improving overall light output.
Solution Approach 2:
The fluorescent substance acts as an intermediary between the laser-excited phosphor and the final light output. The phosphor first converts laser light to fluorescence, which then serves as the excitation source for the fluorescent substance. This intermediary approach distributes the excitation energy more effectively, preventing phosphor saturation while maintaining high conversion efficiency.
2Power
If high power density laser light is used to excite the phosphor, then light output is improved, but color uniformity decreases due to color irregularity in the irradiation spot
Solution Approach 1:
The invention segments the light generation process into phosphor fluorescence and fluorescent substance emission, which are spatially and spectrally separated. The phosphor is excited by laser light in a controlled manner, while the fluorescent substance is excited by UV irradiation from a different direction, reducing color irregularity and improving color uniformity across the irradiation spot.
Solution Approach 2:
The invention applies different excitation methods to different regions: the phosphor is excited by laser light with specific spatial distribution, while the fluorescent substance is excited by UV irradiation from the side surface. This local differentiation of excitation quality ensures uniform color output across the entire emission area, preventing color irregularity.
3Manufacturing precision
If excessive light scattering is used to improve color uniformity, then color uniformity is improved, but light extraction efficiency decreases
Solution Approach 1:
The fluorescent substance serves as an intermediary that converts UV light to visible light with high extraction efficiency. By using the fluorescent substance excited from the side surface, the system achieves good color uniformity without relying on excessive scattering, thereby maintaining high light extraction efficiency.
Solution Approach 2:
The invention introduces a new dimension for light input by irradiating the fluorescent substance from the side surface rather than from above. This dimensional change allows UV light to penetrate and excite the fluorescent substance without requiring excessive scattering, thus maintaining high extraction efficiency while achieving color uniformity.
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
This design enhances color uniformity and chromaticity flexibility while maintaining high conversion efficiency, preventing output saturation and improving the reliability and industrial applicability of the light emitting device.
Implementation Method 1
the bottom wall of the housing is made of a reflecting member that reflects the laser light
Implementation Method 2
the first phosphor is excited by diffused light of the laser light diffused by the bottom wall
Implementation Method 3
the first wavelength converter containing a first phosphor, wherein the first phosphor is excited by diffused light of the laser light diffused by the bottom wall
Data Source
Figure 1~1(b)
Figure 2~2(b)
Figure 3
AI summary
A light emitting device (A) includes a laser light source (1) that emits laser light (100), a housing (2A) that includes a bottom wall (3) and a side wall, and a first wavelength converter (20) provided on the side wall, the first wavelength converter (20) containing a first phosphor. The bottom wall of the housing is irradiated with the laser light emitted from the laser light source, and the first phosphor is excited by diffused light of the laser light diffused by the bottom wall. With such a configuration, the light emitting device (A) improves color uniformity and chromaticity flexibility while increasing power density of output light.