OLED Display Substrate Via Layout for Color Cast Suppression
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Solution Overview
Problem
The issue of color cast in OLED display devices is caused by the inclination of anodes in sub-pixels of different colors, leading to mismatched light emission directions and resulting in color shifts when viewed from different angles.
Innovation Solution
The display substrate design includes a specific arrangement of via holes to move the location of certain via holes closer to their corresponding anodes, ensuring the flatness of anodes and reducing resistance, thereby preventing short-circuiting and color cast.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If via holes are arranged in conventional positions, then manufacturing is simplified, but anode flatness deteriorates and resistance increases causing color cast
Solution Approach 1:
The patent applies local quality by differentiating the positioning of via holes based on their location relative to anodes. Specifically, via holes corresponding to anodes in certain columns are positioned at different distances from the anodes compared to via holes in other columns. This localized variation in via hole positioning ensures uniform anode flatness across all columns while avoiding unnecessary complexity in the overall design.
2Reliability
If anodes are inclined due to via hole positioning, then via hole alignment is simplified, but light emission direction mismatches causing color cast
Solution Approach 1:
The patent implements local quality by adjusting via hole positioning specifically for anodes in certain columns to ensure they are at equal distances from their corresponding anodes. This localized adjustment corrects anode inclination and ensures uniform light emission directions across all sub-pixels, preventing color cast while maintaining via hole alignment simplicity.
3Reliability
If via holes are positioned far from anodes, then short-circuiting risk is reduced, but resistance increases affecting display performance
Solution Approach 1:
The patent applies parameter changes by optimizing the distance between via holes and anodes based on column position. Via holes for anodes in first and second columns are positioned at a first distance, while via holes for anodes in third and fourth columns are positioned at a second distance. This parameter variation ensures reliable electrical connections with appropriate resistance levels, balancing short-circuit prevention and power consumption.
Data Source
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Figure 4B~5B
AI summary
A display substrate and a display device are disclosed. The display substrate includes a base substrate; a pixel circuit layer, including a plurality of pixel driving circuits; a first conductive layer; a first planarization layer; and a second conductive layer; the second conductive layer includes a plurality of conductive portions, and the plurality of conductive portions include a first conductive portion, the first conductive portion includes a closed annular portion, the closed annular portion is separated from at least one conductive portion adjacent thereto in the first direction in the second conductive layer, each light emitting element groups includes a first light emitting element, the first light emitting element includes a first anode, and an orthographic projection of the first anode on the base substrate overlaps with an orthographic projection of the closed annular portion on the base substrate; the plurality of conductive portions further include a second conductive portion adjacent to the first conductive portion, and an orthographic projection of the second conductive portion on the base substrate overlaps with the orthographic projection of the first anode on the base substrate. Therefore, the display substrate can effectively alleviate the phenomenon of color cast.