OLED Display Substrate UV Blocking and Light Extraction Layer
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Solution Overview
Problem
OLED display devices face issues with low light extraction efficiency and short service life, particularly in ultraviolet radiation environments, due to outgassing in the pixel definition layer, which reduces their application range.
Innovation Solution
A display substrate structure is introduced with a modulation structure layer that includes a light extraction layer and a light block layer, where the light block layer is positioned to block ultraviolet rays from entering the pixel definition layer, improving the service life and light extraction efficiency by absorbing UV rays and reducing outgassing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional OLED structure is used, then the device can achieve basic light emission, but the light extraction efficiency is low and service life is short due to UV-induced outgassing
Solution Approach 1:
The patent introduces a light block layer as an intermediary component between the cathode and pixel definition layer. This layer specifically blocks ultraviolet rays from reaching the pixel definition layer, preventing UV-induced outgassing while allowing visible light to pass through. The light block layer acts as a mediator that protects the pixel definition layer from harmful UV radiation without affecting the overall light emission function of the OLED device.
Solution Approach 2:
The patent converts the harmful effect of ultraviolet radiation into a beneficial protective function. By introducing the light block layer with specific optical properties, the previously harmful UV rays are now utilized to highlight the need for protection, and the layer itself becomes the solution that transforms the UV threat into an opportunity to enhance device reliability through targeted UV blocking while maintaining visible light transmission.
2Reliability
If the pixel definition layer is exposed to ultraviolet rays, then the device structure remains simple, but outgassing occurs which reduces service life
Solution Approach 1:
The patent segments the light modulation function into distinct layers: a light extraction layer and a light block layer. The light block layer is specifically positioned between the cathode and pixel definition layer to handle UV blocking, while other layers handle visible light extraction and modulation. This segmentation allows each layer to specialize in a specific function, improving overall device reliability without requiring a complete restructuring of the OLED architecture.
Solution Approach 2:
The patent applies local quality by giving different optical properties to different layers. The light block layer has high UV absorption properties specifically where needed to protect the pixel definition layer, while the light extraction layer has high visible light transmission properties. This localized functional differentiation protects vulnerable areas from UV damage without affecting the overall light emission efficiency, thereby improving reliability with minimal added complexity.
3Productivity
If no light extraction layer is used, then the device structure is simpler, but light extraction efficiency is low
Solution Approach 1:
The patent designs the light extraction layer to perform multiple functions simultaneously: it extracts visible light from the organic light emitting layer, modulates the light output, and works in conjunction with the light block layer to provide UV protection. This multi-functionality allows a single layer to contribute to both light extraction efficiency and device protection, improving productivity without proportionally increasing structural 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
The proposed structure significantly enhances the service life of OLED display devices in ultraviolet environments and improves light extraction efficiency, making them more suitable for various applications by reducing UV-induced degradation.
Implementation Method 1
the light block layer is configured to block ultraviolet rays from being incident on a pixel definition layer
Implementation Method 2
the refractive index of the light extraction layer is greater than the refractive indexes of the cathode and the light block layer
Data Source
AI summary
The display substrate includes a driving structure layer disposed on a base substrate, a light emitting structure layer disposed on the side of the driving structure layer away from the base substrate, and a modulation structure layer disposed on the side of the light emitting structure layer away from the base substrate; the modulation structure layer includes a light extraction layer and a light block layer, the light extraction layer is disposed on the side of a cathode in the light emitting structure layer away from the base substrate, the light block layer is disposed on the side of the light extraction layer away from the base substrate, the refractive index of the light extraction layer is greater than the refractive indexes of the cathode and the light block layer, and the light block layer is configured to block ultraviolet rays from being incident on a pixel definition layer.