Light Conversion Lens for LED Color Tuning and Thermal Management
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Solution Overview
Problem
Existing white light emitting diodes (LEDs) using YAG:Ce phosphor have limitations in color temperature and color rendering index, making it difficult to achieve improved color reproducibility and optical characteristics, and are prone to performance degradation due to heat issues.
Innovation Solution
A light emitting device with a body containing a cavity, a light emitting part, and a light conversion part with convex curved surfaces that enhances light conversion efficiency, reduces heat-related performance degradation, and improves reliability and durability by increasing the contact area for heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If YAG:Ce phosphor is used in white LED, then the LED can be easily fabricated with blue LED pumping, but the color temperature and color rendering index are limited and cannot be adjusted
Solution Approach 1:
The patent divides the single phosphor material into multiple phosphor materials (YAG:Ce and at least one additional phosphor from red, green, or yellow phosphors). Each phosphor material contributes to different wavelength ranges, enabling independent adjustment of color temperature and CRI while maintaining ease of fabrication through phosphor blending in the encapsulant resin.
Solution Approach 2:
The patent uses composite phosphor materials by combining YAG:Ce phosphor with other phosphor materials (red phosphor, green phosphor, or yellow phosphor) in specific ratios. This composite approach enables simultaneous achievement of high CRI (>80), adjustable color temperature (2000K-10000K), and maintained ease of manufacturing through the liquid crystal polymer encapsulant.
2Ease of manufacture
If YAG:Ce phosphor is used in white LED, then the LED can be easily fabricated, but the color rendering index is low (70-75) compared to incandescent lamps (>80) and fluorescent lamps (>75)
Solution Approach 1:
The patent segments the phosphor composition into multiple components with complementary emission spectra. YAG:Ce provides yellow emission while additional phosphors (red, green, or yellow) fill spectral gaps, achieving CRI >80 by ensuring complete visible spectrum coverage while maintaining easy fabrication through liquid crystal polymer encapsulation.
Solution Approach 2:
The patent employs composite phosphor systems combining YAG:Ce with red phosphor (K2SiF6:Mn4+), green phosphor (β-SiAlON:Eu2+), or yellow phosphor (Lu3Al5O12:Ce3+) in optimized ratios. This composite material approach achieves high CRI (>80) and maintains ease of manufacturing through the liquid crystal polymer encapsulant resin that enables uniform phosphor distribution.
3Productivity
If light conversion part with convex curved surfaces is used, then light conversion efficiency is improved, but the contact area for heat dissipation must be increased
Solution Approach 1:
The patent employs light conversion parts with convex curved surfaces (spherical, hemispherical, or aspherical shapes) to improve light extraction efficiency and uniformity. The curved geometry enhances light conversion by reducing internal reflection and improving phosphor excitation uniformity, while the liquid crystal polymer encapsulant provides thermal management through its inherent heat dissipation properties.
Solution Approach 2:
The patent uses liquid crystal polymer encapsulant as an intermediary material that simultaneously serves optical and thermal functions. This encapsulant material enables effective heat dissipation from the convex curved light conversion parts while maintaining the optical benefits of the curved geometry, thus resolving the trade-off between light conversion efficiency and heat dissipation area.
4Reliability
If multiple phosphor materials are used to improve color reproducibility, then the device complexity increases
Solution Approach 1:
The patent merges multiple phosphor materials (YAG:Ce and additional red, green, or yellow phosphors) into a single encapsulated unit using liquid crystal polymer resin. This combining approach achieves high color reproducibility (CRI >80) and adjustable color temperature while maintaining simple device structure and easy manufacturing through single-step encapsulation, thus reducing overall device complexity despite using multiple phosphors.
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 solution provides improved color reproducibility, optical characteristics, and reliability by effectively converting light and managing heat, resulting in enhanced performance and durability of the light emitting device.
Implementation Method 1
a light conversion part provided in the cavity and converting the light from the light emitting part
Data Source
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AI summary
Disclosed is a light emitting device. The light emitting device includes a body having a cavity, a light emitting part in the cavity, a reflective layer on an inner surface of the cavity, and a light conversion layer adjacent to the reflective layer. The light emitting device includes a body having the cavity, a light emitting part in the cavity, and a light conversion part on a path of a light from the light emitting part. The light conversion part includes a first light conversion lens part, and a second light conversion lens part beside the first light conversion lens part.