Segmented Common Power Lines for OLED IR-Drop
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Solution Overview
Problem
Organic light emitting displays using digital driving methods experience luminance differences across display regions due to IR-drop phenomena, particularly in large-sized displays, where voltage decreases lead to significant current reductions, causing uneven luminance.
Innovation Solution
The implementation of a display device with a substrate having common power lines that supply a common power voltage to pixels, including first and second common power lines connected at the center, and pixel power lines that supply distinct voltages to pixels, with resistances optimized to maintain constant voltage differences across the display region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single common power line is used to supply voltage to pixels in a large-sized display, then the device complexity is reduced, but luminance uniformity deteriorates due to IR-drop phenomenon causing significant voltage decrease across the display region
Solution Approach 1:
The single common power line is divided into multiple segments (first common power line and second common power line) that extend in opposite directions from a central connection point. This segmentation allows voltage to be supplied from multiple locations, reducing the IR-drop along each segment and improving luminance uniformity across the large display region while maintaining relatively simple device complexity
Solution Approach 2:
The power line configuration transitions from a one-dimensional single line to a two-dimensional radial pattern with multiple lines extending from a central point. This dimensional change enables voltage distribution across a larger area with reduced resistance, addressing the luminance uniformity issue in large-sized displays
2Illumination intensity
If the resistance of common power lines is reduced to maintain consistent voltage, then luminance uniformity is improved, but the manufacturing precision requirements increase
Solution Approach 1:
By segmenting the power line into multiple parallel paths (first and second common power lines), the total resistance is reduced without requiring any single line to have extremely low resistance. This approach improves voltage consistency while maintaining achievable manufacturing precision for each individual line
Solution Approach 2:
Multiple common power lines are merged at a central connection point to form a combined power distribution network. This merging creates parallel current paths that reduce overall resistance and improve voltage consistency across the display, while each individual line can be manufactured within standard precision tolerances
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 reduces luminance differences between display regions, enhancing image quality by maintaining consistent voltage and current distribution across the display area, particularly in large-sized organic light emitting displays.
Implementation Method 1
the organic light emitting display adopting or utilizing a digital driving method may exhibit an IR-drop phenomenon, and if a voltage that is applied to a pixel is decreased, current that flows thereto may abruptly decrease
Implementation Method 2
the organic light emitting display is a display device that displays information, such as an image or text, using light that is generated through combination of holes and electrons
Data Source
AI summary
A display device including a substrate having a display region on which an image is configured to be displayed, a plurality of pixels on the display region of the substrate, and a plurality of common power lines on the display region of the substrate and configured to supply a common power voltage to the plurality of pixels, the plurality of common power lines including first and second common power lines extending in a first direction, the second common power line being connected to the plurality of pixels arranged along the first direction, and the first and second common power lines being connected to each other in a central portion of the display region.