OLED Pixel Power Lines with Variable Widths for Brightness Uniformity
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Solution Overview
Problem
Organic light emitting displays experience non-uniformity in pixel brightness due to variations in power transmission caused by differences in internal resistance of pixel power source lines, leading to brightness inconsistencies across pixels.
Innovation Solution
The use of pixel power source lines of varying widths, with the blue sub-pixel lines having the largest width and green sub-pixel lines the smallest, to match the specific voltage drops and current error ratios of each sub-pixel, thereby reducing power variations and maintaining an optimal aperture ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If uniform width pixel power source lines are used, then manufacturing is simplified, but brightness non-uniformity occurs due to varying internal resistance
Solution Approach 1:
The patent applies local quality by varying the width of pixel power source lines according to their specific location and electrical characteristics. Different sub-pixels (red, green, blue) receive power lines with widths optimized for their individual voltage drop and current error ratio requirements, rather than using a uniform width for all lines. This localized optimization compensates for resistance variations and achieves brightness uniformity across the display.
Solution Approach 2:
The patent changes the physical parameter of line width to compensate for electrical parameter variations. By adjusting the width parameter of power source lines, the patent compensates for differences in internal resistance across different pixel locations, thereby maintaining consistent current delivery and brightness uniformity without requiring complex active compensation circuits.
2Illumination intensity
If larger width power source lines are used to reduce resistance, then voltage drop is reduced, but aperture ratio decreases
Solution Approach 1:
The patent applies local quality by assigning different line widths to different sub-pixels based on their specific electrical characteristics. Rather than uniformly increasing all line widths to reduce resistance, the patent optimizes each line's width individually - using larger widths only where needed to compensate for higher resistance or voltage drop, and smaller widths where sufficient voltage stability is already achieved. This localized approach minimizes the total area occupied by power lines, preserving aperture ratio while maintaining voltage stability.
3Manufacturing precision
If different width lines are used for different sub pixels, then brightness uniformity is improved, but manufacturing complexity increases
Solution Approach 1:
The patent implements local quality by varying line widths according to the specific electrical characteristics of each sub-pixel location. This approach achieves brightness uniformity by compensating for location-specific resistance variations through tailored line width optimization, rather than using a one-size-fits-all manufacturing approach.
Solution Approach 2:
The patent applies preliminary action by pre-calculating and designing the optimal line width for each pixel power source line before manufacturing. The different width configurations are built into the display structure during the fabrication process, eliminating the need for post-manufacturing adjustments or complex real-time compensation mechanisms, thereby simplifying the overall manufacturing process despite the varied line widths.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces non-uniformity in pixel brightness and minimizes brightness deterioration by tailoring the width of pixel power source lines to the specific requirements of each sub-pixel, resulting in improved display uniformity and reduced aperture ratio changes.
Implementation Method 1
the organic light emitting display displays an image using organic light emitting diodes (OLEDs) that generate light by the recombination of electrons and holes
Data Source
AI summary
An organic light emitting display is capable of reducing variation in power transmitted to pixels to reduce or prevent non-uniformity of brightness from being generated. The organic light emitting display includes a pixel including a red sub pixel, a green sub pixel, and a blue sub pixel and first pixel power source lines for supplying a first pixel power from a first pixel power source to the red sub pixel, the green sub pixel, and the blue sub pixel, wherein the first pixel power source lines coupled to at least two different color sub pixels of the red, green and blue sub pixels have different widths. The first pixel power source lines have widths that may correspond to a voltage drop of the first pixel power source or may correspond to deterioration of the respective sub pixels to which they are coupled.