OLED Display Panel Subpixel Geometry for Luminance Efficiency
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Solution Overview
Problem
Organic light emitting display panels suffer from low light extraction efficiency and luminance efficiency due to light being trapped inside the panel, and image distortion issues arise with varying viewing angles.
Innovation Solution
A display panel design featuring a substrate with subdivided subpixels, an overcoat layer with convex and concave areas connected by inclined surfaces, and anode electrodes with inclined surfaces, along with a bank layer and multiple organic light emitting layers, enhances light emission and reduces color shift across viewing angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a conventional organic light emitting display panel is used, then the structure is simple, but light extraction efficiency is low and luminance efficiency deteriorates because light is trapped inside the panel
Solution Approach 1:
The patent applies curvature by forming inclined surfaces on the overcoat layer and anode electrode. These inclined surfaces redirect trapped light toward the viewing direction, improving light extraction efficiency without requiring complex additional optical layers. The curved/angled geometry transforms the flat panel structure into one that actively manages light propagation.
Solution Approach 2:
The patent introduces dimensional complexity by adding inclined surfaces that operate in three-dimensional space. Instead of relying solely on flat, two-dimensional light emission, the inclined surfaces create additional light extraction pathways in the vertical and angular dimensions, allowing trapped light to escape more effectively.
2Reliability
If a conventional flat display panel is used, then manufacturing is simple, but image distortion occurs at different viewing angles
Solution Approach 1:
The patent introduces asymmetry through inclined surfaces with specific angles (e.g., 27° or greater) that are designed to compensate for viewing angle effects. These asymmetric geometric features redirect light in a way that maintains consistent color and image quality across different viewing angles, counteracting the natural asymmetry in light propagation from flat panels.
Solution Approach 2:
The inclined surfaces create a curved light extraction path that helps maintain consistent optical properties across different viewing angles. This geometric curvature compensates for the angular dependence of light emission, reducing color shift and image distortion when viewed from oblique positions.
3Loss of energy
If inclined surfaces are added to improve light extraction, then luminance efficiency improves, but manufacturing precision requirements increase
Solution Approach 1:
The patent specifies particular parameter ranges for the inclined surfaces, such as angles of 27° or greater and height differences of 0.7 μm or more. By defining specific parameter thresholds rather than requiring precise continuous values, the design achieves improved light extraction while maintaining manufacturability within standard fabrication tolerances.
Solution Approach 2:
The inclined surfaces are formed in specific localized regions (overcoat layer and anode electrode areas) rather than requiring precision across the entire panel. This localized approach concentrates the light extraction enhancement where it is most effective while limiting the overall manufacturing complexity and precision requirements.
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 design improves luminance efficiency and minimizes color shift, ensuring high luminous efficiency and consistent image quality across different viewing angles.
Implementation Method 1
the overcoat layer may include a first inclined surface surrounding the concave area in at least one of the first, second and third subpixels... At least one of the first, second and third anode electrodes may include a second inclined surface formed along with the first inclined surface
Implementation Method 2
some of the light emitted from the organic light emitting layer cannot be emitted outside the organic light emitting display panel, and therefore trapped inside the organic light emitting display device
Data Source
AI summary
A display panel can include first, second and third subpixels on a substrate; an overcoat layer in the first, second and third subpixels; a concave area and a convex area in the overcoat layer in at least one of the first, second and third subpixels, the concave area being connected to the convex area through a first inclined surface of the overcoat layer; first, second and third anode electrodes corresponding to the first, second and third subpixels, respectively, at least one of the first, second and third anode electrodes includes a second inclined surface overlapping with the first inclined surface of the overcoat layer; first, second and third organic light emitting layers on the first, second and third anode electrodes, respectively; and a bank layer on the overcoat layer, the bank layer including a third inclined surface, at least one of the first, second and third inclined surfaces reflects light.