Reflective Cup-Shaped Pixel Defining Layer for OLED Efficiency
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Solution Overview
Problem
Conventional OLED display devices suffer from reduced display efficiency due to waveguide light being absorbed by the second electrode, leading to a lower external quantum effect and light-emitting efficiency.
Innovation Solution
A display back panel with a patterned second electrode confined in a reflective cup-shaped structure, where the first electrode reflects waveguide light, allowing it to pass freely and avoiding absorption by the second electrode, enhancing the external quantum effect and light-emitting efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional OLED structure with a continuous second electrode is used, then the device structure is simple and easy to manufacture, but the waveguide light is absorbed by the second electrode, reducing light-emitting efficiency and external quantum effect
Solution Approach 1:
The second electrode is segmented into multiple discrete electrode regions corresponding to different sub-pixels (red, green, blue), separated by insulating pixel defining layers. This segmentation prevents the second electrode from absorbing waveguide light that should be reflected by the first electrode, thereby improving light-emitting efficiency while maintaining manufacturing simplicity through standard patterning processes
Solution Approach 2:
The harmful function of the second electrode (absorbing waveguide light) is extracted and eliminated by introducing pixel defining layers that block the second electrode from contacting the light-emitting layer in certain regions. This allows waveguide light to be reflected by the first electrode without being absorbed, improving external quantum effect
2Reliability
If the second electrode covers the entire light-emitting layer, then the electrical connection is complete and easy to achieve, but the external quantum effect is reduced due to absorption of reflected waveguide light
Solution Approach 1:
The second electrode is designed with local quality variations - it is present in some regions (contacting the light-emitting layer for electrical connection) and absent in other regions (where pixel defining layers block it). This local presence/absence pattern ensures reliable electrical connection where needed while preventing harmful light absorption in regions where waveguide light reflection is desired, thereby improving external quantum effect
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 significantly improves light-emitting efficiency and external quantum effect, resulting in lower energy consumption and better display performance compared to conventional OLED devices.
Implementation Method 1
the first electrode reflect waveguide light laterally propagated by the light-emitting layer
Implementation Method 2
waveguide light laterally propagated by the light-emitting layer and reflected by a first electrode may freely pass from the display device and not be absorbed by the second electrode
Data Source
AI summary
A display back panel may include a substrate, an insulating layer disposed on one side of the substrate and including a plurality of recesses, the plurality of recesses including a bottom surface, a first electrode disposed on a surface of the insulating layer away from the substrate, a pixel defining layer disposed on a surface of the first electrode away from the substrate and including a plurality of openings, a light-emitting layer disposed in the plurality of openings and covering the first electrode, and a second electrode disposed on a surface of the light-emitting layer away from the substrate. Therein, the first electrode may reflect waveguide light laterally propagated by the light-emitting layer, thereby improving a light-emitting efficiency of the light-emitting layer. Further, the reflected waveguide light may not be absorbed by the second electrode, thereby enhancing an external quantum effect of the light-emitting layer.