OLED Pixel Defining Layer Shielding Against UV Light Damage
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Solution Overview
Problem
Existing display devices face reliability issues due to damage from external light, which can cause characteristic deterioration of the organic electroluminescent element and pixel defining layer, particularly in the ultraviolet and visible wavelength range.
Innovation Solution
Incorporation of a light blocking layer that covers the top surface and side surface of the pixel defining layer, including a light absorbent that absorbs light in the wavelength band ranging from 350 nm to 450 nm, to prevent external light from reaching the pixel defining layer and insulating layer, thereby protecting the organic electroluminescent element.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a light blocking layer is added to protect the pixel defining layer and insulating layer from external light, then the reliability of the organic electroluminescent element is improved, but the device complexity increases
Solution Approach 1:
A light blocking layer is introduced as an intermediary component between the external environment and the pixel defining layer/insulating layer. This layer absorbs harmful light in the 350-450 nm wavelength range, preventing it from reaching and damaging the organic electroluminescent element and surrounding structures, thereby improving reliability without fundamentally changing the device architecture
Solution Approach 2:
The light blocking layer is formed using composite materials that combine light-absorbing properties with compatibility to the existing device structure. The layer integrates with the pixel defining layer and insulating layer, providing protective functionality while maintaining structural coherence and avoiding excessive complexity
2Reliability
If the light blocking layer covers the top surface and side surface of the pixel defining layer, then the protection against light damage is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The light blocking layer extends from the top surface to the side surface of the pixel defining layer, adding a vertical dimension to the protection. This three-dimensional coverage ensures that light cannot reach the protected areas from any angle, improving protection effectiveness while using standard layer deposition techniques that do not require excessive manufacturing precision
3Object-affected harmful factors
If the light blocking layer absorbs light in the wavelength band ranging from 350 nm to 450 nm, then the damage to the pixel defining layer and insulating layer is reduced, but the device complexity increases
Solution Approach 1:
The light blocking layer is designed with specific optical parameters to absorb light in the 350-450 nm wavelength range. By adjusting the material composition and thickness of this layer, optimal light absorption is achieved in the harmful ultraviolet and visible range while maintaining transparency or appropriate optical properties for the display function, reducing light-induced damage without adding complex systems
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 light blocking layer effectively reduces damage to the pixel defining layer and insulating layer from external light, enhancing the reliability and display quality of the organic electroluminescent element without affecting its light emitting characteristics.
Implementation Method 1
a light blocking layer covering a top surface and a side surface of the pixel defining layer... the light blocking layer may include at least one light absorbent that absorbs light of a wavelength band ranging from 350 nm to 450 nm
Data Source
AI summary
A display device including a substrate that includes a circuit layer; an insulating layer on the substrate; a pixel defining layer on the insulating layer, the pixel defining layer having an opening exposing a region of a top surface of the insulating layer; a light blocking layer covering a top surface and a side surface of the pixel defining layer; and an organic electroluminescent element in the opening, wherein the organic electroluminescent element includes a first electrode on the region of the top surface of the insulating layer exposed through the opening; at least one organic layer on the first electrode; and a second electrode on the at least one organic layer.