Curved Electrode Organic EL Display Light Blocking
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Solution Overview
Problem
Organic electroluminescence display apparatuses face reduced display quality due to external light reflection from metal layers, which affects light efficiency and image quality.
Innovation Solution
Incorporating a light blocking layer with a smaller opening than the pixel definition layer opening, combined with a curved electrode and optical layers to effectively block external light and enhance light extraction efficiency, while maintaining a concave surface structure to condense and emit light efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a light blocking layer is added to prevent external light reflection, then display quality improves, but device complexity increases
Solution Approach 1:
The light blocking layer is integrated within the existing display structure, nested between the pixel definition layer and the encapsulation layer. This nesting approach prevents external light reflection without adding a separate external component, thereby improving display quality while minimizing increases in device complexity.
Solution Approach 2:
The light blocking layer is segmented into multiple openings corresponding to different pixel regions, allowing selective light blocking. This segmentation enables precise control over where light blocking occurs, improving display quality while maintaining structural efficiency and avoiding unnecessary complexity.
2Object-affected harmful factors
If the light blocking layer completely covers the electrode, then external light reflection is prevented, but light extraction efficiency decreases
Solution Approach 1:
The light blocking layer is designed with local quality variations through strategically positioned openings that expose specific electrode portions. This allows the structure to block external light in certain regions while permitting light extraction in others, simultaneously addressing both external light reflection prevention and light extraction efficiency maintenance.
Solution Approach 2:
The curved electrode surface, which could potentially cause uneven light distribution, is converted into a beneficial feature by using it to condense and uniformly distribute extracted light across wide viewing angles. The same curvature that might cause issues is leveraged to improve light extraction efficiency and viewing characteristics.
3Object-affected harmful factors
If the opening of light blocking layer is made smaller, then external light reflection is reduced, but light extraction area is reduced
Solution Approach 1:
The electrode is designed with a curved surface that condenses light extraction from a potentially small opening area and distributes it uniformly across wide viewing angles. This curvature compensates for the reduced opening area by improving light extraction efficiency per unit area, allowing smaller openings to achieve the same effective light output.
Solution Approach 2:
The refractive indices of optical layers are optimized and adjusted to enhance light extraction efficiency. By changing optical parameters such as refractive index matching and layer thickness, the system maximizes light extraction from the reduced opening area, compensating for the smaller light extraction area while maintaining reduced external light reflection.
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 significantly reduces external light reflectance and improves light efficiency, enhancing display quality by effectively blocking external light and uniformly distributing light across a wide viewing angle.
Implementation Method 1
the first electrode includes a curved electrode portion having a concave second upper surface... the curved electrode portion satisfies the following Equation 1... to condense and emit light efficiently
Implementation Method 2
a light blocking layer disposed on the second electrode and including a second opening defined therethrough... effectively block external light
Implementation Method 3
a first optical layer disposed on the light blocking layer, and the first optical layer has a first refractive index equal to or greater than a refractive index of the encapsulation layer... uniformly distributing light across a wide viewing angle
Data Source
AI summary
An organic electroluminescence display apparatus includes an insulating layer including a concave portion having a concave first upper surface, a first electrode including a curved electrode portion having a concave second upper surface overlapped with the concave portion, a pixel definition layer including a first opening defined therethrough to expose the second upper surface, an organic layer disposed on the first electrode, a second electrode disposed on the organic layer, and a light blocking layer including a second opening defined therethrough. The second opening has a width smaller than the first opening and overlaps with the first opening.