Wavelength Conversion Element for Thermal Stress Reduction
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Summary
Problems
The existing wavelength conversion elements face issues with temperature gradients in the fluorescent layer due to high-density excitation light irradiation, leading to potential cracks and reduced luminous efficiency.
Innovation solutions
A wavelength conversion element with a fluorescent layer where the volume density of fluorescent particles is higher on the substrate side than on the incident surface side, and the layer is at least 5 times thicker than the average particle size, with a substrate for heat radiation, moderating the temperature gradient and enhancing heat dissipation.
TRIZ Analysis
Specific contradictions:
General conflict description:
Principle concept:
If excitation light is condensed and irradiated at high density onto the fluorescent layer, then luminous efficiency is improved, but temperature gradient increases causing cracks and reduced reliability
Why choose this principle:
The fluorescent layer is designed with non-uniform fluorescent particle density distribution, where particles are more densely distributed near the substrate side and less densely near the incident surface side. This local variation in density allows different regions to handle thermal stress differently, with higher density regions providing better heat radiation near the substrate while lower density regions reducing thermal stress concentration near the incident surface, thereby preventing cracks while maintaining luminous efficiency.
Principle concept:
If fluorescent particles are dispersed uniformly in the binder, then manufacturing is simplified, but temperature gradient causes stress and cracks
Why choose this principle:
Instead of uniform dispersion, the invention employs localized density variation of fluorescent particles within the binder matrix. The particles are arranged such that their concentration gradient creates optimal thermal management properties in different regions of the layer, addressing the temperature uniformity issue while remaining compatible with conventional manufacturing processes like screen printing or sintering.
Application Domain
Data Source
AI summary:
A wavelength conversion element with a fluorescent layer where the volume density of fluorescent particles is higher on the substrate side than on the incident surface side, and the layer is at least 5 times thicker than the average particle size, with a substrate for heat radiation, moderating the temperature gradient and enhancing heat dissipation.
Abstract
A wavelength conversion element includes a fluorescent portion in which fluorescent particles are dispersed in a binder. The fluorescent portion has a first surface and a second surface which are opposite to each other in a thickness direction and excitation light is irradiated from a second surface side. A volume density of the fluorescent particles in a first portion is higher than that in a second portion where the fluorescent portion is divided in the thickness direction into two of the first portion on a first surface side and the second portion on the second surface side. A thickness of the fluorescent portion is at least 5 times as long as an average particle size of the fluorescent particles.