Curved Electrode Pixel Structure for Wide-Angle Luminance Stability
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Solution Overview
Problem
Display devices experience significant quality deviation and luminance decrease when viewed from different angles due to the structure of light-emitting devices and pixel driving circuits, leading to inconsistent image quality across varying viewing angles.
Innovation Solution
The display device incorporates a design with a protruding portion on the upper planarization layer, a bank insulating layer with an opening exposing a portion of the first electrode, and a curved first electrode overlapping with the edge of the protruding portion, along with an intermediate electrode symmetrically positioned, to enhance light emission and reduce angle-dependent luminance variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the first electrode is disposed parallel to the upper surface of the device substrate, then the manufacturing process is simple, but the luminance decreases rapidly when viewed from an angle
Solution Approach 1:
The first electrode is configured with a curved surface having a specific radius of curvature, replacing the conventional flat parallel arrangement. This curvature causes light to be emitted at multiple angles, maintaining luminance consistency across different viewing directions and resolving the contradiction between manufacturing simplicity and angular luminance performance.
2Ease of manufacture
If a planarization layer is added to cover the pixel driving circuit, then the light-emitting device can be properly disposed, but the image quality deviation according to viewing angle increases
Solution Approach 1:
The upper planarization layer is designed with a protruding portion that locally extends into the pixel area, creating different surface heights in different regions. This local structural variation allows the light-emitting device to be properly disposed while the curved first electrode compensates for the viewing angle dependency, maintaining image quality consistency.
3Stability of the object's composition
If the first electrode covers the protruding portion, then the structural integrity is improved, but the emission angle needs to be enhanced
Solution Approach 1:
The first electrode's curved surface configuration enables light to be emitted at wider and more uniform angles compared to a flat electrode. The curvature radius is specifically designed to optimize the emission angle while maintaining structural integrity, allowing the electrode to cover the protruding portion effectively.
Data Source
AI summary
A display device includes a light-emitting device that may be disposed on an upper planarization layer of a pixel area. A bank insulating layer defining an emission area may be disposed on the upper planarization layer. The upper planarization may include a protruding portion overlapping with the emission area. An edge of the protruding portion may be a curved surface having a constant curvature. The light-emitting device may include a first electrode, a light-emitting layer and a second electrode, which are sequentially stacked on the emission area. The protruding portion may be covered by the first electrode. Thus, in the display device, a decrease in luminance according to a viewing angle may be reduced.