Dual Pixel Power Source Lines for OLED Brightness Uniformity
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Solution Overview
Problem
In organic light emitting displays, IR drops along pixel power source lines cause non-uniform brightness due to varying voltage supply to pixels, especially as the panel size increases, leading to inconsistent light emission.
Innovation Solution
The implementation of first and second pixel power source lines, each receiving a pixel driving voltage from separate power supply sources, with each pixel comprising a pair of light emitting diodes coupled to these lines, ensuring uniform distance and resistance, thereby reducing IR drop effects and brightness non-uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single pixel power source line is used to supply voltage to all pixels, then the device structure is simple, but IR drops cause non-uniform brightness across the display
Solution Approach 1:
The single pixel power source line is segmented into multiple pixel power source lines (first and second sets), with each line supplying voltage to specific regions of pixels. This segmentation reduces the length of each power source line, thereby reducing IR drops and improving brightness uniformity across the display while maintaining reasonable structural complexity
Solution Approach 2:
Different pixel power source lines are assigned to different regions of the display (odd columns vs even columns, or upper vs lower regions). Each local region receives power through its dedicated line, ensuring that local brightness uniformity is maintained by minimizing the distance and resistance variations in each local power delivery path
2Area of stationary object
If the panel size is increased to meet display requirements, then the display area is improved, but IR drops increase causing greater brightness non-uniformity
Solution Approach 1:
As the panel size increases, the power source lines are segmented into multiple shorter lines rather than using one long line across the entire panel. This allows the display area to be expanded while each individual power source line maintains a manageable length, preventing excessive IR drops even in large-scale displays
Solution Approach 2:
The power source lines are arranged in a two-dimensional grid pattern (multiple lines extending in opposite directions) rather than a single linear arrangement. This dimensional approach allows power to be delivered efficiently across large areas by providing multiple parallel paths, reducing the cumulative effect of IR drops in large panels
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 configuration ensures uniform voltage distribution to pixels, reducing IR drop-induced brightness variations and maintaining consistent light emission across the display, even as the panel size enlarges.
Implementation Method 1
the organic light emitting diode is a self-emission element for emitting light from a phosphor by the recombination of electrons and holes
Implementation Method 2
the voltages supplied to the pixels are reduced by the IR drops on the pixels that are remote from an external power supply source
Data Source
AI summary
An organic light emitting display having first pixel power source lines receiving a pixel driving voltage from first power supply sources and second pixel power source lines arranged between the first pixel power source lines and receiving a pixel driving voltage from second power supply sources, the light emitting diode of each of a plurality of pixels included in an image display unit is divided into two, and the divided light emitting diodes are coupled to the different pixel power source lines so that brightness non-uniformity of the image display unit caused by the IR drops of the pixel power source lines is reduced or prevented.