OLED Pixel Array Layout for Uniform Brightness Centers
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Solution Overview
Problem
Current OLED display devices face challenges with non-uniform actual brightness centers due to larger red and blue sub-pixels, leading to reduced display panel brightness and increased aging speed when operating at high driving currents to meet brightness requirements.
Innovation Solution
The pixel array design includes alternately arranged red and blue sub-pixels with green sub-pixels in between, forming virtual quadrilaterals with non-90° interior angles and adjusted sub-pixel shapes to ensure uniform brightness distribution, achieved by varying the distances and orientations of sub-pixel corners and symmetry axes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If high driving current is used to meet brightness requirements, then display panel brightness is improved, but OLED device aging speed increases and lifetime is reduced
Solution Approach 1:
The patent applies local quality by creating non-uniform sub-pixel shapes with different area distributions. Specifically, red and blue sub-pixels are designed with larger areas compared to green sub-pixels, and each sub-pixel has asymmetric corner rounding with different radii. This local differentiation in sub-pixel geometry compensates for the inherently different luminous efficiencies of red, green, and blue OLED materials, allowing the display to achieve uniform brightness across all sub-pixels without requiring excessive driving current, thereby extending OLED device lifetime.
2Illumination intensity
If larger red and blue sub-pixels are used to compensate for lower luminous efficiency, then brightness requirement can be met, but actual brightness centers become non-uniform
Solution Approach 1:
The patent implements asymmetry by designing sub-pixels with non-uniform corner rounding. Each sub-pixel has four corners with different rounding radii, where opposite corners share the same radius but adjacent corners have different radii. For example, in red sub-pixels, two opposite corners have a first rounding radius while the other two opposite corners have a second rounding radius. This asymmetric design allows precise control over the light emission distribution within each sub-pixel, ensuring that the actual brightness centers align uniformly across the display panel despite the larger physical area of red and blue sub-pixels.
3Manufacturing precision
If sub-pixel shapes are adjusted to ensure uniform brightness distribution, then brightness center uniformity is improved, but device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the sub-pixel shape optimization into distinct, independently controllable parameters. Each sub-pixel is characterized by four corner rounding radii that can be independently adjusted, along with the overall sub-pixel area. This segmentation allows the complex problem of brightness uniformity to be broken down into manageable geometric parameters, simplifying the design and manufacturing process while achieving the desired uniformity in actual brightness centers across the display panel.
Data Source
AI summary
There is provided a pixel array including a plurality of sub-pixels, which include first sub-pixels, second sub-pixels, and third sub-pixels. The first and third sub-pixels are alternately arranged along a row direction and form a plurality of first pixel rows, the first and third sub-pixels, which are in a same column, in the plurality of first pixel rows are alternately arranged, and the second sub-pixels are arranged along the row direction and form second pixel rows. Lines sequentially connecting centers of any two of the first sub-pixels and any two of the third sub-pixels, which are arranged in an array, together form a first virtual quadrilateral, and one of the second sub-pixels is in each first virtual quadrilateral. At least one interior angle of the first virtual quadrilateral is not 90°. At least one of the first, second and third sub-pixels has a corner circularly or rectilinearly chamfered.