Organic Light Emitting Display Bus Line and Black Matrix Design
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Solution Overview
Problem
Organic light emitting display apparatuses face issues with IR drop and decreased contrast ratio due to the high resistance of top emission-type organic light emitting display apparatuses, which affects the uniformity of light emission and overall performance.
Innovation Solution
A method involving the formation of an opposite electrode bus line using aerosol jet printing, covered by a black matrix, to reduce IR drop and maintain high contrast ratio, where the bus line is strategically placed between adjacent pixel electrodes and the black matrix is formed to minimize reflection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a top emission-type organic light emitting display apparatus is used, then the aperture ratio is improved, but the device has high resistance causing an IR drop
Solution Approach 1:
The opposite electrode is segmented into two functional parts: a transparent electrode portion covering the pixel area for light emission, and a separate conductive bus line portion for current supply. This segmentation allows each part to optimize its function - the transparent electrode maintains high aperture ratio while the bus line provides low resistance current path.
Solution Approach 2:
A black matrix is introduced as an intermediary element that covers the bus line. This black matrix serves as a visual barrier to prevent light reflection from the conductive bus line, thereby maintaining high contrast ratio while allowing the bus line to perform its electrical function underneath.
2Reliability
If a conductive bus line is added to prevent IR drop, then the resistance is reduced, but the contrast ratio is lowered
Solution Approach 1:
A black matrix is introduced as an intermediary element that covers the bus line. This black matrix serves as a visual barrier to prevent light reflection from the conductive bus line, thereby maintaining high contrast ratio while allowing the bus line to perform its electrical function underneath.
Solution Approach 2:
The black matrix is selectively positioned only where needed - covering the bus line in non-pixel areas where it would otherwise cause reflection. This localized application maintains contrast ratio in critical viewing areas while preserving the electrical functionality of the bus line.
3Illumination intensity
If the opposite electrode is made transparent, then light emission is improved, but the resistance increases causing IR drop
Solution Approach 1:
The opposite electrode is segmented into two functional parts: a transparent electrode portion covering the pixel area for light emission, and a separate conductive bus line portion for current supply. This segmentation allows each part to optimize its function - the transparent electrode maintains high aperture ratio while the bus line provides low resistance current path.
Solution Approach 2:
The opposite electrode structure serves multiple functions through different portions: the transparent electrode portion provides both electrical function and light emission, while the bus line portion provides purely electrical function with optimized conductivity. This multi-functional design resolves the conflict between transparency and resistance.
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 effectively prevents IR drop and maintains a high contrast ratio by reducing the resistance of the opposite electrode and minimizing light reflection, enhancing the reliability and performance of the organic light emitting display apparatus.
Implementation Method 1
the opposite electrode bus line and the black matrix are formed by aerosol jet printing
Implementation Method 2
the black matrix covers side surfaces and an upper surface of the opposite electrode bus line
Data Source
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AI summary
An organic light emitting display apparatus capable of preventing or reducing an IR drop and a decrease in a contrast ratio, and a method of manufacturing the same. The organic light emitting display apparatus includes: a substrate; a plurality of thin film transistors on the substrate; a plurality of organic light emitting diodes, each of the organic light emitting diodes including: a pixel electrode electrically connected to a corresponding one of the thin film transistors, a portion of an opposite electrode, the opposite electrode being above the substrate and covering all of the substrate, and an intermediate layer between the pixel electrode and the opposite electrode and comprising at least an organic light emitting layer; an opposite electrode bus line between adjacent pixel electrodes of the organic light emitting diodes on the opposite electrode of the organic light emitting diodes; and a black matrix covering the opposite electrode bus line.