OLED Display Assisting Lines for Voltage Drop Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Electrical color mixing between adjacent pixels in organic EL display devices reduces display quality due to lateral current transmission through functional layers, leading to unwanted light emission from non-intended pixels.
Innovation Solution
Incorporating assisting lines on the common electrode between sub-pixels with varying distances based on the color of adjacent sub-pixels, where distances are longer for sub-pixels with high relative luminosity factors and shorter for those with low relative luminosity factors, to control current flow and minimize electrical color mixing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a transparent conductive film formed of ITO, IZO or the like is used as a common electrode, then the display device can be manufactured with standard materials, but a significant voltage drop is caused in the central area due to high resistance
Solution Approach 1:
The common electrode is segmented into a cathode and multiple assisting lines (first assisting lines and second assisting lines) with different resistance values. The cathode has high resistance while the assisting lines have low resistance, creating a segmented structure that reduces overall voltage drop in the central area.
Solution Approach 2:
Different regions of the common electrode structure are assigned different resistance characteristics. The cathode maintains high resistance for manufacturability, while the assisting lines positioned in specific areas (central region) have low resistance to locally reduce voltage drop and improve display uniformity.
2Use of energy by moving object
If the cathode resistance is increased to reduce current consumption, then energy efficiency improves, but voltage drop in the central area increases
Solution Approach 1:
The common electrode is divided into a high-resistance cathode and low-resistance assisting lines. This segmentation allows the cathode to maintain high resistance for low current consumption while the assisting lines compensate for voltage drop in the central area.
Solution Approach 2:
The assisting lines act as intermediary conductive paths between the high-resistance cathode and the pixel electrodes. They mediate the electrical connection, allowing the cathode to maintain high resistance for energy efficiency while the assisting lines provide low-resistance pathways to reduce voltage drop.
3Illumination intensity
If a thin film of MgAg or transparent conductive film is used as common electrode, then light transmission is improved for top emission type, but resistance increases causing voltage drop
Solution Approach 1:
The common electrode structure is segmented into a light-transmissive cathode (MgAg or transparent conductive film) and assisting lines. The cathode maintains high light transmission for top emission type displays, while the assisting lines provide additional conductive pathways to reduce voltage drop caused by the high resistance of the thin film cathode.
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 effectively reduces electrical color mixing by adjusting the resistance values and current paths, maintaining optimal OLED performance without sacrificing efficiency or chromaticity, thereby enhancing display quality and reducing unwanted light emission.
Implementation Method 1
An EL element is capable of emitting light of a color of any of various wavelengths in accordance with a light emitting material selected to form a light emitting layer
Data Source
AI summary
A display device includes a display area including a plurality of pixels located in a matrix. The plurality of pixels include first sub pixels and second sub pixels, the second sub pixels being adjacent to the first sub pixels. The display device further comprises a plurality of assisting lines formed between the first sub pixels and the second sub pixels, the areas not overlapping the openings of the banks as seen in a plan view. As seen in a cross-sectional view, regarding each of the first sub pixels and the second sub pixel adjacent thereto, a distance between an edge of the opening of the bank demarcating the first sub pixel and a corresponding assisting line, among the assisting lines, is longer than a distance between an edge of the opening of the bank demarcating the second sub pixel and the corresponding assisting line.