Quantum Dot Light Enhancement Substrate for High CRI Lighting
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Solution Overview
Problem
Current solid-state lighting devices, such as OLEDs, face challenges in achieving high light extraction efficiency and color rendering index (CRI) due to total internal reflection and wave-guiding effects, leading to limited external quantum efficiency and unstable color output.
Innovation Solution
Incorporating a layer of quantum dots dispersed in a host material with a refractive index higher than the substrate and conductive layers, combined with scattering agents, to enhance light out-coupling and convert blue light into high CRI white light, while maintaining stability over a wide range of intensities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If quantum dots are incorporated with higher refractive index host material to enhance light out-coupling, then light extraction efficiency is improved, but device complexity increases
Solution Approach 1:
The patent uses composite materials by combining quantum dots with a host material that has a higher refractive index than both the substrate and conductive layers. This composite structure enhances light out-coupling efficiency by reducing total internal reflection at the interfaces, thereby improving light extraction without requiring complex additional optical components
Solution Approach 2:
The invention changes the refractive index parameter of the host material to be higher than the substrate and conductive layers. This parameter change optimizes the optical properties for light extraction, allowing more light to escape the device structure by modifying the refractive index mismatch at the interfaces
2Illumination intensity
If quantum dots are used to convert blue light into white light, then color rendering index is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent applies local quality by using quantum dots with specific size distributions to target particular wavelength conversions. Different quantum dot sizes convert different portions of the blue spectrum to specific colors, allowing precise control over the white light output spectrum and achieving high color rendering index through localized spectral engineering
3Productivity
If scattering agents are combined with quantum dots, then light out-coupling is enhanced, but loss of substance increases
Solution Approach 1:
The invention merges scattering agents with quantum dots into a single integrated layer. This combination allows the same layer to perform both light scattering (enhancing out-coupling) and wavelength conversion (producing white light), thereby achieving enhanced light extraction without requiring separate additional layers that would increase material usage and complexity
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 significantly increases light extraction efficiency and achieves tunable, high CRI white light with improved stability and efficiency, overcoming the limitations of existing OLED technologies.
Implementation Method 1
a color conversion material comprising quantum dots disposed over a predetermined region of a surface of the substrate
Implementation Method 2
a conductive material disposed over at least a portion of the color conversion material, the conductive material being transparent to light within a second predetermined range of wavelengths
Implementation Method 3
a layer of quantum dots dispersed in a host material with a refractive index higher than the substrate and conductive layers
Data Source
AI summary
A component including a substrate, at least one layer including a color conversion material including quantum dots disposed over the substrate, and a layer including a conductive material (e.g., indium-tin-oxide) disposed over the at least one layer. (Embodiments of such component are also referred to herein as a QD light-enhancement substrate (QD-LES).) In certain preferred embodiments, the substrate is transparent to light, for example, visible light, ultraviolet light, and/or infrared radiation. In certain embodiments, the substrate is flexible. In certain embodiments, the substrate includes an outcoupling element (e.g., a microlens array). A film including a color conversion material including quantum dots and a conductive material is also provided. In certain embodiments, a component includes a film described herein. Lighting devices are also provided. In certain embodiments, a lighting device includes a film described herein. In certain embodiments, a lighting device includes a component described herein.