Layered Wavelength Converter Platelet for LED Edge Color Uniformity
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Solution Overview
Problem
Conventional shaped surface luminance LEDs suffer from unwanted color variation, higher thermal resistance, and reduced internal quantum efficiency due to non-uniform current distribution, leading to increased power consumption and design complexity.
Innovation Solution
Implement a wavelength converter platelet with laterally varying concentrations of scattering pores, combining layers with different scattering densities to achieve a desired luminance profile without altering the LED die design, thereby reducing thermal resistance and maintaining efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If non-uniform current distribution is used to create shaped surface luminance, then luminance distribution is improved, but internal quantum efficiency decreases and thermal resistance increases
Solution Approach 1:
The wavelength converter is designed with spatially varying properties: the first region has different wavelength conversion characteristics than the second region. This local differentiation allows each region to optimize its light conversion efficiency, maintaining high internal quantum efficiency while achieving the desired shaped surface luminance profile through localized optical property variations rather than non-uniform current distribution.
Solution Approach 2:
The patent changes optical parameters of the wavelength converter by varying the thickness of the converter layer across different regions. The first region has a different thickness than the second region, which alters the wavelength conversion characteristics and enables shaped surface luminance while maintaining uniform current distribution and high efficiency.
2Illumination intensity
If non-uniform current distribution is used to control luminance, then luminance profile is improved, but thermal resistance increases
Solution Approach 1:
The wavelength converter features localized variations in thickness and optical properties across different regions. This local quality differentiation enables tailored light conversion in each region, achieving the desired luminance profile through optical design rather than electrical non-uniformity, thereby avoiding the thermal penalties associated with non-uniform current distribution.
3Illumination intensity
If conventional shaped surface luminance LEDs are used, then luminance distribution is improved, but color variation increases
Solution Approach 1:
The patent employs parameter changes in the wavelength converter thickness to control luminance distribution. By varying the thickness parameter across different regions, the optical path length and wavelength conversion efficiency are adjusted, achieving shaped surface luminance while maintaining consistent color characteristics through controlled optical transformation rather than non-uniform electrical excitation.
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 maintains luminance profile while reducing IQE penalties and thermal resistance, allowing for simpler manufacturing processes and cost-effective production of LEDs with controlled color variation.
Implementation Method 1
A shaped surface luminance wavelength converter includes a first wavelength converting layer, which has a first concentration of scattering pores. A second wavelength converting layer is disposed over the first wavelength converting layer and has a second concentration of scattering pores
Data Source
Figure 1A~1B
Figure 2
Figure 3A~3B
AI summary
An LED die, a wafer of LED dies, and methods of manufacture are described. A shaped surface luminance wavelength converter platelet includes a first wavelength converting layer, which has a first concentration of scattering pores. A second wavelength converting layer is disposed over the first wavelength converting layer and has a second concentration of scattering pores with the second concentration of scattering pores being larger than the first concentration of scattering pores.