Organic Light Emitting Display Capacitor Electrode Asymmetry
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Solution Overview
Problem
The display quality of organic light emitting displays is degraded due to critical dimension (CD) distribution, leading to the generation of horizontal line shaped spots, which is costly to mitigate by lowering the tolerance of manufacturing masks.
Innovation Solution
The organic light emitting display design alternates the widths of the upper and lower electrodes of capacitors between adjacent pixels, ensuring the same overlap area while differing in size, thereby preventing the degradation of display quality caused by CD distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the mask tolerance is lowered to reduce CD distribution effects, then the manufacturing precision is improved, but the manufacturing cost increases considerably
Solution Approach 1:
The patent applies asymmetry by intentionally designing the capacitor electrodes with different widths (first width for one electrode, second width for the other electrode) rather than using symmetric equal-width electrodes. This asymmetric design compensates for CD distribution effects without requiring higher mask precision, thereby resolving the contradiction between manufacturing precision and manufacturing cost.
Solution Approach 2:
The patent implements local quality by making each capacitor electrode pair have specific width characteristics tailored to its position and function. The first electrode has a first width and the second electrode has a second width, allowing local optimization of capacitor performance while maintaining uniform overlap area across all pixels, thus avoiding the need for costly high-precision masks.
2Device complexity
If the capacitor electrode widths are made equal for simplicity, then the device complexity is reduced, but horizontal line shaped spots are generated due to CD distribution
Solution Approach 1:
The patent resolves this contradiction by introducing asymmetric electrode widths while maintaining the same overlap area for all capacitors. The first electrode has width W1 and the second electrode has width W2 where W1 ≠ W2, but their overlap area is kept constant. This asymmetric design eliminates horizontal line spots caused by CD distribution without significantly increasing device complexity.
Solution Approach 2:
The patent changes the width parameters of the capacitor electrodes from equal widths to different widths (first width and second width) while maintaining the overlap area parameter constant. This parameter change compensates for CD distribution effects and prevents display quality degradation without requiring complex additional structures.
Data Source
AI summary
The general inventive concept relates to an organic light emitting display that has the same area where the upper and lower electrodes of a capacitor are overlapped for adjacent pixels, for respective pixels that constitute the organic light emitting display but implements the sizes of the upper and lower electrodes to be different. This thereby prevents the display quality of horizontal line shaped spot generated due to the effects of a critical dimension (CD) distribution from being degraded.