Uneven Pixel Circuit Sizing for Display Yield
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Solution Overview
Problem
Self-light emitting display units, such as organic EL and LED displays, face manufacturing yield issues due to uneven pixel pattern densities caused by differences in drive current or capacitive element sizes, leading to increased pattern defect rates.
Innovation Solution
The solution involves setting the sizes of color pixel circuits unevenly within the pixel circuit according to the magnitude ratio of drive currents or area ratios between overlapping regions and capacitive elements, ensuring even pixel pattern densities across all colors, thereby reducing pattern defect rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If sizes of drive transistor and accumulated capacitative element are adjusted according to necessary display drive current for each color, then light emission luminance uniformity is improved, but pixel pattern density becomes uneven and pattern defect rate increases
Solution Approach 1:
The patent applies local quality by making the pixel circuit sizes color-specific rather than uniform. Each color (R, G, B) has its pixel circuit size adjusted according to its specific drive current requirements, creating localized variations in circuit dimensions that optimize luminance output for each color while maintaining overall display uniformity.
Solution Approach 2:
The patent employs asymmetry by intentionally creating uneven pixel circuit sizes across different colors. The pixel circuits for R, G, and B are designed with different dimensions to match their respective drive current characteristics, breaking the symmetry of uniform sizing to achieve better luminance control and reduce pattern defects.
2Ease of manufacture
If pixel circuit sizes are made uniform across all colors, then manufacturing process is simplified, but pixel pattern density becomes uneven and manufacturing yield is lowered
Solution Approach 1:
The patent resolves this contradiction by implementing local quality through color-specific pixel circuit sizing. Instead of applying a uniform size across all pixels, each color region has its pixel circuit dimensions optimized for its specific electrical characteristics, thereby maintaining manufacturing simplicity while improving yield through localized optimization.
3Stability of the object's composition
If pixel circuit sizes are adjusted to match drive current requirements, then display uniformity is improved, but device complexity increases due to multiple size specifications
Solution Approach 1:
The patent manages device complexity by applying local quality principles - each color region has its pixel circuit size specifically tailored to its drive current requirements. This localized approach achieves display uniformity without requiring complex global optimization, as each local region is independently optimized for its specific characteristics.
Data Source
AI summary
A self-light emitting display unit capable of improving manufacturing yield is provided. Sizes of color pixel circuits corresponding to pixels for R, G, and B are respectively set unevenly within a pixel circuit according to a magnitude ratio of drive currents which allow color self-light emitting elements in the pixel to emit with a same light emission luminance. Thereby, the pattern densities of color pixel circuits respectively corresponding to the pixels for R, G, and B become even to each other, and the pattern defect rate as the whole pixel circuit is decreased.