OLED Pixel Defining Layer With Reflective Cladding for Light Extraction
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Solution Overview
Problem
Organic light-emitting diode (OLED) display devices suffer from low light output efficiency, with only about 20% of emitted light being output into the air, while 80% is restricted or consumed within the device, necessitating a solution to reduce internal light consumption and enhance service life.
Innovation Solution
A pixel defining layer comprising an insulating transparent cladding layer and a reflecting layer, where the reflecting layer is configured to reflect light emitted from the light-emitting layer, with specific thickness, inclination, and material properties to maximize light reflection and output efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional OLED structure is used, then the device structure is simple, but the light output efficiency is low (only 20% of light is output into air)
Solution Approach 1:
The pixel defining layer is divided into two functional segments: a transparent cladding layer for insulation and a reflecting layer for light redirection. This segmentation allows each layer to perform its specific function optimally while working together to solve the light efficiency problem.
Solution Approach 2:
The reflecting layer is designed with an inclined side surface that redirects light from the horizontal plane to the vertical direction (toward the air interface). This dimensional change in light path redirects previously trapped lateral light into the air, improving light output efficiency without complicating the overall device structure.
2Loss of energy
If the reflecting layer thickness is increased to improve light reflection, then the light reflection efficiency is improved, but the manufacturing complexity increases
Solution Approach 1:
The reflecting layer thickness is optimized to a specific range (0.5-1.4 μm) that provides sufficient light reflection (greater than 90%) while remaining compatible with standard OLED manufacturing processes. This parameter optimization achieves high reflection efficiency without requiring complex manufacturing steps.
3Loss of energy
If the reflecting layer completely surrounds the light-emitting layer, then light reflection is maximized, but the device layer formation becomes more difficult
Solution Approach 1:
The reflecting layer partially surrounds the device layer, covering the lateral surfaces where light escape occurs most significantly. This partial coverage achieves the majority of light reflection benefits while leaving the top surface open for device layer formation, balancing manufacturing ease with light 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
The solution effectively increases light output efficiency by reflecting lateral light emitted from the OLED device, reducing waveguide effects and enhancing light emission performance, thereby improving the overall efficiency and longevity of OLED display panels.
Implementation Method 1
a reflecting layer in the transparent cladding layer, wherein the reflecting layer is configured to reflect light emitted from a light-emitting layer of the organic light-emitting diode display panel
Data Source
AI summary
Provided is a pixel defining layer of an organic light-emitting diode display panel. The pixel defining layer includes: an insulating transparent cladding layer; and a reflecting layer in the transparent cladding layer, wherein the reflecting layer is configured to reflect light emitted from a light-emitting layer of the organic light-emitting diode display panel. Organic light-emitting diode display panels and methods for manufacturing an organic light-emitting diode display panel are also provided.