OLED Concavo-Convex Passivation Layer Light Extraction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current OLEDs face limitations in enhancing luminous power per unit pixel electrode and the lifespan of thin film transistors due to constraints in developing high-efficiency luminescent materials and increasing electrical current, which affects the overall efficiency and lifespan of the device.
Innovation Solution
The design incorporates a substrate with a first and second signal line, thin film transistors, a passivation layer with a concavo-convex surface, and a light emitting member with refractive index differences between layers, along with a second electrode, to increase the luminescent area and efficiency by altering the reflection angle of light through refractive index differences and concavo-convex structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the efficiency of luminescent material is enhanced or electrical current is increased to increase luminous power per unit pixel, then luminous power per unit pixel is improved, but device lifespan and overall efficiency deteriorate due to practical limitations and stress on TFTs
Solution Approach 1:
The patent applies curvature by forming a convex portion on the pixel electrode surface with a specific radius of curvature (5-50 μm). This curved structure increases the luminous area by reflecting and scattering light, thereby enhancing luminous power without increasing electrical current or using less efficient luminescent materials, thus preserving device lifespan
Solution Approach 2:
The patent transitions from a planar pixel electrode to a three-dimensional structure with a convex portion. This dimensional change creates additional light extraction paths and increases the effective luminous area, achieving higher luminous power without the trade-off of reduced device lifespan
2Power
If electrical current applied to pixel electrodes is increased to increase luminous power, then luminous power is improved, but TFT lifespan and efficiency deteriorate due to increased stress
Solution Approach 1:
The convex portion on the pixel electrode creates a curved surface that enhances light extraction efficiency through reflection and scattering. This allows the device to achieve higher luminous power at lower electrical current levels, reducing stress on TFTs and extending their operational lifespan
Solution Approach 2:
The patent changes the physical parameter of the pixel electrode surface from flat to convex with a specific radius of curvature. This parameter change increases the luminous area and light extraction efficiency, enabling higher luminous power without increasing electrical current, thus protecting TFT lifespan
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 enhances the luminous power per unit pixel electrode and improves light extraction efficiency by increasing the luminescent area and altering the reflection angle of light, thereby addressing the limitations of existing OLEDs.
Implementation Method 1
The refractive indices of the light emitting member and the first passivation layer are different, and the refractive indices of the first passivation layer and the first electrode are different
Implementation Method 2
altering the reflection angle of light through refractive index differences
Data Source
AI summary
An organic light emitting device (OLED) is presented that includes: signal lines formed on a substrate; thin film transistors formed on the substrate and electrically connected to the signal lines; a first passivation layer having a concavo-convex surface; a first electrode formed on the first passivation layer; a partition formed on the first electrode and having an opening extending to the first electrode; a light emitting member formed in the opening and covered by a second electrode. The refractive indices of the light emitting member and the first passivation layer are different, and the refractive indices of the first passivation layer and the first electrode are different. The concavo-convex surface increases the luminescent surface area without decreasing the opening size, thereby enhancing the luminous power per unit pixel electrode. Forming an interface of materials whose refractive indices differ by at least 0.2 within the OLED increases light extraction efficiency.