OLED Display Subpixel Layout for Reduced Viewing-Angle Color Cast
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Solution Overview
Problem
Existing OLED display technologies face challenges in achieving uniformity and reducing color cast issues due to the complexity of the manufacturing process, particularly when using inkjet printing for forming light-emitting functional layers, which can lead to non-flat surfaces and color deviations at different viewing angles.
Innovation Solution
The display substrate design includes specific geometric relationships and overlapping configurations of electrode plates and openings in sub-pixels, along with conductive structures, to minimize color cast by controlling the distances and angles of chromaticity coordinate points, ensuring uniform light emission across viewing angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If inkjet printing is used to form light-emitting functional layers, then manufacturing flexibility and pattern definition are improved, but surface flatness deteriorates leading to color cast issues
Solution Approach 1:
The patent introduces a planarization layer with different properties in different regions: a first planarization layer filling the light-emitting area and a second planarization layer in the non-light-emitting area. This local differentiation allows the light-emitting surface to remain flat for uniform color output while maintaining the manufacturing flexibility of inkjet printing for forming the light-emitting functional layers.
2Manufacturing precision
If complex multi-layer structures are used to improve display uniformity, then color cast is reduced, but device complexity increases
Solution Approach 1:
The patent combines the planarization function with the pixel definition function by integrating the planarization layer into the existing pixel structure. The planarization layer is formed as part of the pixel definition layer structure, merging multiple functions into a single integrated component rather than adding separate complex structures.
Solution Approach 2:
The planarization layer serves multiple functions simultaneously: it planarizes the surface for uniform light emission, defines pixel boundaries, and provides structural support. This multi-functionality reduces the need for additional dedicated structures, thereby limiting the increase in device complexity while achieving improved display uniformity.
3Manufacturing precision
If the second electrode plate is positioned closer to the opening edges, then manufacturing tolerance is reduced, but color cast increases due to viewing angle deviations
Solution Approach 1:
The patent changes the geometric parameters of the second electrode plate, specifically making its length in the second direction greater than its length in the first direction (creating a rectangular rather than square configuration). This parameter change allows the electrode plate to extend further toward the opening edges in one direction while maintaining appropriate spacing in the other direction, thereby achieving both manufacturing tolerance and color cast reduction.
Data Source
AI summary
Provided are a display substrate and a display device. The display substrate includes: a base substrate and a plurality of sub-pixels on the base substrate; each sub-pixel includes: a pixel circuit including a storage capacitor including a first electrode plate and a second electrode plate; a light-emitting element; and a pixel definition layer. The sub-pixels include a plurality of openings, orthographic projections of the opening and the second electrode plate on the base substrate are overlapped; the second electrode plate includes a first edge and a second edge extending in the first direction; the opening includes a first edge and a second edge extending in the first direction; the first edge of the second electrode plate is closer to the first edge of the opening; the second edge of the second electrode plates is closer to the second edge of the opening.