Luminescent Concentrator Gradient Converter Efficiency
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Solution Overview
Problem
Luminescent concentrators currently have limited efficiency, with only about 18% of converted light being outcoupled, and existing solutions do not effectively enhance this efficiency without increasing costs or shifting the color point.
Innovation Solution
A luminescent concentrator with a radiation converter element concentration at least three times higher than necessary to absorb 98% of light source radiation, optimized to increase efficiency by 10-20%, using materials like Lu3Al5O12:Ce and other luminescent materials that absorb UV and blue radiation to convert into green, yellow, or red emission, with a higher concentration of cerium ions to enhance conversion efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the radiation converter concentration is increased to improve light absorption, then the light absorption efficiency improves, but the light outcoupling efficiency decreases due to increased reabsorption
Solution Approach 1:
The patent applies local quality by creating a non-uniform distribution of radiation converter elements within the waveguide. The concentration is highest near the light source where absorption is needed, and decreases toward the exit face where outcoupling occurs. This gradient distribution allows different regions to have optimized properties: high absorption near the source, high transmission at the exit.
Solution Approach 2:
The patent transitions from considering only the concentration magnitude to considering the spatial distribution dimension. By optimizing the concentration profile as a function of position within the waveguide (creating a gradient), the system resolves the contradiction between absorption and outcoupling efficiency that cannot be solved by uniform concentration alone.
2Productivity
If the radiation converter concentration is increased to absorb more light, then the conversion efficiency improves, but reabsorption of emitted light increases reducing overall efficiency
Solution Approach 1:
The patent implements local quality by spatially varying the radiation converter concentration. High concentration regions are positioned where incident light intensity is highest (near the source), while low concentration regions are positioned where emitted light needs to exit. This local optimization allows high conversion efficiency where needed while minimizing reabsorption losses where light must escape.
Solution Approach 2:
The patent applies preliminary action by pre-distributing radiation converter elements in a optimized concentration profile before light propagation occurs. The gradient is designed in advance to predictably guide light absorption and emission processes, preventing reabsorption losses before they can occur by ensuring emitted light passes through progressively lower converter concentrations.
3Ease of manufacture
If a uniform radiation converter concentration is used to simplify manufacturing, then the manufacturing process is easier, but the light outcoupling efficiency is limited to maximum 18%
Solution Approach 1:
The patent applies parameter changes by transitioning from a uniform concentration parameter to a spatially varying concentration parameter. The concentration becomes a function of position within the waveguide, creating a gradient profile. This parameter transformation enables the system to achieve 20-24% outcoupling efficiency while remaining manufacturable through established gradient fabrication techniques.
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 increased radiation converter concentration in the luminescent concentrator enhances light outcoupling efficiency from 18% to 20-24%, improving the overall efficiency of the lighting device while maintaining desired color properties.
Implementation Method 1
The radiation converter element is configured to absorb at least part of the light source radiation and to convert into radiation converter element radiation
Implementation Method 2
light should especially remain in total internal reflection (TIR) until the end of the concentrator
Data Source
Figure 1~2
Figure 3A~3B
Figure 3C~3D
AI summary
The invention provides a device (1) comprising (i) a luminescent concentrator (100), the luminescent concentrator (100) comprising a waveguide (4000) having a radiation input face (4100), a radiation exit face (4200), and a width (W) defined by the radiation input face (4100) and an opposite face (4500), the waveguide (4000) comprising a radiation converter element (20) distributed in the waveguide (4000) with a converter concentration; (ii) a solid state light source (10) configured to irradiate the radiation input face (4100)of the waveguide (4000) with solid state light source radiation (11); wherein the radiation converter element (20) is configured to absorb at least part of the light source radiation (11) and to convert into radiation converter element radiation (21), and wherein the converter concentration is at least three times higher than necessary to absorb 98% of the light source radiation (11) over the width (W) of the waveguide (4000).