OLED Subpixel Emission Area and Zigzag Arrangement
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Solution Overview
Problem
Organic light emitting display devices experience luminance deviations over time due to differing luminance lifetimes of sub-pixels, leading to color changes and potential defects during the manufacturing process.
Innovation Solution
The areas of emission regions for sub-pixels are adjusted based on their individual luminance lifetimes, with green sub-pixels having larger emission regions than non-green sub-pixels to ensure uniform luminance and minimize color changes, and the emission regions are arranged in a zigzag pattern to distribute stress evenly during deposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If all sub-pixels are given the same emission region area, then the manufacturing process is simplified, but luminance uniformity deteriorates over time due to different luminance lifetimes of different colored sub-pixels
Solution Approach 1:
The patent applies local quality by assigning different emission region areas to different colored sub-pixels based on their specific luminance lifetime characteristics. Green sub-pixels, which have shorter luminance lifetime, are given larger emission regions while red and blue sub-pixels with longer lifetimes have smaller regions, ensuring that all sub-pixels contribute equally to overall luminance throughout the display's operational life.
2Device complexity
If emission regions are arranged in a regular pattern, then the display structure is simple, but stress distribution during mask deposition becomes uneven causing manufacturing defects
Solution Approach 1:
The patent employs asymmetry by arranging emission regions in a zigzag pattern rather than a regular grid. This asymmetric arrangement ensures that during mask deposition, stress is distributed more uniformly across the substrate, preventing concentration of stress at specific locations and thereby reducing manufacturing defects while maintaining structural simplicity.
Data Source
AI summary
An organic light emitting display device includes a plurality of sub pixels including a plurality of red sub pixels, a plurality of green sub pixels, and a plurality of blue sub pixels, wherein each sub pixel of the plurality of sub pixels includes an emission region and a non-emission region surrounding the emission region, wherein each sub pixel of the plurality of sub pixels has the same size, wherein areas of emission regions of green sub pixels are the same as or larger than an area of an emission region of at least one red sub pixels and blue sub pixels, and wherein the emission region of green sub pixels extends into a portion of the non-emission region of the red sub pixels or a portion of the non-emission region of the blue sub pixels.