Structured Luminescence Conversion Layer for OLED Spectral Tuning
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Solution Overview
Problem
Conventional uniform down-conversion layers in OLEDs offer limited flexibility in designing output spectra, restricting the compromise between efficiency and color rendering due to their fixed thickness and phosphor concentration.
Innovation Solution
A structured luminescence conversion layer with alternating color-changing and non-color-changing regions is applied over a transparent layer, allowing for greater flexibility in designing output spectra by adjusting the ratio of these regions, which absorb and emit light at different spectra, enhancing light extraction and color rendering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a uniform down-conversion layer with fixed thickness and phosphor concentration is used, then the device structure is simple and easy to manufacture, but the flexibility in designing output spectra is limited
Solution Approach 1:
The down-conversion layer is segmented into multiple regions with different phosphor concentrations and thicknesses. Each region can independently convert light to different wavelengths, enabling flexible spectral design. The segmentation allows the device to achieve multiple output spectra by controlling which regions are activated or by adjusting the relative contributions of each region.
Solution Approach 2:
Different regions of the down-conversion layer are assigned different local properties, specifically varying phosphor concentrations and thicknesses. This allows each region to have optimized characteristics for specific wavelength conversions, providing local spectral tuning capabilities while maintaining overall device functionality.
2Illumination intensity
If the phosphor concentration and layer thickness are increased to improve color rendering, then the color rendering index improves, but the light extraction efficiency decreases due to increased absorption
Solution Approach 1:
The down-conversion layer is divided into multiple regions, each with optimized phosphor concentration and thickness for specific color conversions. This segmentation allows light to be converted to different wavelengths in different regions, improving overall color rendering while maintaining better light extraction efficiency by avoiding excessive absorption in any single region.
Solution Approach 2:
The phosphor concentration and layer thickness parameters are varied across different regions of the down-conversion layer. By optimizing these parameters locally in each region, the device achieves improved color rendering index while minimizing energy loss through excessive absorption, as each region operates at optimal conversion efficiency.
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 approach enables precise tuning of the output spectra, improving both efficiency and color rendering by combining the non-absorbed and emitted light, offering a better compromise between these parameters compared to uniform layers.
Implementation Method 1
A color-changing material is defined herein as a material which absorbs photons related to lower wavelength(s) and which reemits all of them or a part of them
Implementation Method 2
A color-changing material is defined herein as a material which absorbs photons related to lower wavelength(s) and which reemits all of them or a part of them (depending on the quantum yield of the color-changing material) at higher wavelength(s)
Data Source
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AI summary
An apparatus device such as a light source is disclosed which has an OLED device and a structured luminescence conversion layer deposited on the substrate or transparent electrode of said OLED device and on the exterior of said OLED device. The structured luminescence conversion layer contains regions such as color-changing and non-color-changing regions with particular shapes arranged in a particular pattern.