LED Conversion Layer Layout for Angular Color Homogeneity
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Solution Overview
Problem
Optoelectronic components, such as LEDs, face issues with color homogeneity due to varying intensity ratios of primary and secondary radiation across different emission angles, leading to color segregation and efficiency losses when using scattering particles to address this problem.
Innovation Solution
An optoelectronic component design featuring a layer sequence with an active layer and a conversion element comprising a conversion layer and a conversion potting, where the concentration of converter material abruptly decreases from the conversion layer to the potting, ensuring higher concentrations in the conversion layer for primary radiation conversion and lower concentrations in the potting for correction, maintaining constant intensity ratios across emission angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If scattering particles are added to the conversion element to increase color homogeneity, then color homogeneity depending on emission angle is improved, but efficiency of the optoelectronic component deteriorates due to scattering losses and reabsorption losses
Solution Approach 1:
The conversion element is divided into multiple conversion layers with different converter material concentrations. The first conversion layer has a higher concentration of converter material than the second conversion layer, allowing each layer to contribute differently to the radiation conversion process. This segmentation enables color homogeneity improvement without the need for scattering particles that would cause energy losses.
Solution Approach 2:
Different regions of the conversion element are assigned different converter material concentrations tailored to their specific functions. The first conversion layer (closer to the semiconductor chip) has higher converter material concentration for primary radiation conversion, while the second conversion layer has lower concentration for fine-tuning the spectral output. This local quality differentiation achieves color homogeneity without introducing scattering losses throughout the entire conversion element.
2Productivity
If converter material concentration is increased in the conversion layer, then conversion efficiency is improved, but color homogeneity deteriorates due to varying intensity ratios at different emission angles
Solution Approach 1:
The conversion element is segmented into multiple layers with progressively decreasing converter material concentrations. The first conversion layer has high converter material concentration for efficient primary radiation conversion, while subsequent layers have lower concentrations to correct the angular dependence of intensity ratios. This segmentation allows high overall conversion efficiency while maintaining color homogeneity across different emission angles.
Solution Approach 2:
The converter material concentration parameter is varied across different conversion layers. The first conversion layer has a higher converter material concentration optimized for conversion efficiency, while the second conversion layer has a lower concentration optimized for color homogeneity. This parameter change across layers resolves the contradiction between conversion efficiency and color homogeneity.
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 achieves improved color homogeneity and efficiency by maintaining constant color locus and intensity ratios of primary and secondary radiation across emission angles, reducing chromatic aberration and increasing luminous flux compared to components without this configuration.
Implementation Method 1
Converter materials convert the primary radiation emitted by a radiation source wholly or partly into a secondary radiation having an altered, for example longer, wavelength
Implementation Method 2
The color homogeneity depending on the emission angle can be increased for example by scattering particles being added to the conversion element, such that the primary radiation and the secondary radiation have constant intensity ratios as a result of scattering at different emission angles
Data Source
AI summary
An optoelectronic component may include a layer sequence having an active layer configured to emit an electromagnetic primary radiation and a conversion element arranged in the beam path of the primary radiation. The conversion element may include a conversion layer and a conversion potting arranged over the conversion layer. The conversion layer may include a first matrix material and a converter material, and the conversion potting may include a second matrix material and a converter material. There may be a jump in concentration of converter material between the conversion layer and the conversion potting.