Shared Low Refractive Index Layer for OLED Light Extraction
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Solution Overview
Problem
Organic light-emitting devices face challenges with low light extraction efficiency and the complexity of forming separate low refractive index layers for each emission color, which increases costs and reduces efficiency when used across multiple emission colors.
Innovation Solution
A light-emitting apparatus structure is implemented where a low refractive index layer with an optical path based on the emission color of the shortest wavelength is shared across light-emitting devices with different emission colors, accompanied by an optical adjustment layer to enhance extraction efficiency without significant efficiency loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a low refractive index layer is formed for each emission color, then light extraction efficiency is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent applies universality by designing a single low refractive index layer that serves multiple emission colors simultaneously. The layer is positioned and designed to optimize extraction for the shortest wavelength (highest energy) emission, while also providing beneficial extraction enhancement for longer wavelength emissions, thereby eliminating the need for separate optimized layers for each color.
Solution Approach 2:
The patent merges the function of multiple wavelength-specific extraction layers into a single unified low refractive index layer. This consolidation reduces structural complexity while maintaining effective light extraction across multiple emission colors, directly addressing the contradiction between extraction efficiency and device complexity.
2Loss of energy
If a low refractive index layer is formed for each emission color, then light extraction efficiency is improved, but manufacturing cost increases
Solution Approach 1:
The universal low refractive index layer design allows a single manufacturing process to produce a structure that benefits multiple emission colors, reducing material costs, process costs, and fabrication complexity compared to producing separate optimized layers for each wavelength.
Solution Approach 2:
By combining multiple extraction optimization functions into one layer, the patent reduces the number of manufacturing steps, materials required, and process variations needed, thereby lowering overall manufacturing cost while maintaining improved light extraction efficiency.
3Device complexity
If a single low refractive index layer is shared across multiple emission colors, then device complexity is reduced, but light extraction efficiency may decrease for some wavelengths
Solution Approach 1:
The patent applies local quality by optimizing the low refractive index layer's properties (such as refractive index value and thickness) specifically for the shortest wavelength emission, while accepting and managing the extraction performance at other wavelengths. This localized optimization approach balances overall system performance with structural simplicity.
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 inhibits a decrease in light extraction efficiency while improving the extraction efficiency of multiple emission colors, allowing for a high-emission-efficiency light-emitting apparatus to be produced easily, promptly, and inexpensively.
Implementation Method 1
The ordinary refractive index of the first layer A is lower than the ordinary refractive index of the light-emitting layer A at the emission peak wavelength of the light-emitting substance A
Data Source
AI summary
A light-emitting apparatus with high emission efficiency is provided. A light-emitting apparatus including a light-emitting device A and a light-emitting device B is provided. The light-emitting device A includes a first electrode A, a second electrode A, a light-emitting layer A between the first electrode A and the second electrode A, and a first layer A between the first electrode A and the light-emitting layer A. The light-emitting device B includes a first electrode B, a second electrode B, a light-emitting layer B between the first electrode B and the second electrode B, a first layer B between the first electrode B and the light-emitting layer B, and a second layer B between the first electrode B and the light-emitting layer B. The light-emitting layer A contains a light-emitting substance A. The light-emitting layer B contains a light-emitting substance B. An emission peak wavelength of the light-emitting substance A is shorter than an emission peak wavelength of the light-emitting substance B. The first layer A and the first layer B contain the same material. The ordinary refractive index of the first layer A is lower than the ordinary refractive index of the light-emitting layer A at the emission peak wavelength of the light-emitting substance A. The ordinary refractive index of the first layer A is less than or equal to 1.75 at the emission peak wavelength of the light-emitting substance A.