OLED Display With Patterned Organic Layers and Common Cathode
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Solution Overview
Problem
Conventional OLED technologies face challenges in achieving efficient and cost-effective production of saturated color pixels, particularly in flexible and transparent displays, due to limitations in organic thin film deposition and encapsulation, which affect the durability and performance of the devices.
Innovation Solution
The use of organic vapor jet printing (OVJP) to create a substrate with repeating unit areas and discontinuous organic layers, where the organic film is disposed over portions of the device other than the unit areas, allowing for continuous or discontinuous patterns that minimize defects and enhance encapsulation, and the integration of a common cathode addressed by a ground bus line through vias, ensuring efficient electrical connections and reduced mechanical stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional organic thin film deposition is used for OLED fabrication, then continuous film coverage is achieved, but mechanical stress and defects increase
Solution Approach 1:
The patent applies segmentation by transitioning from continuous organic thin film deposition to patterned/discontinuous film deposition. The organic layers are deposited only in specific regions corresponding to pixel areas, leaving inter-pixel regions uncovered. This segmented approach reduces mechanical stress and defect propagation while maintaining device functionality through discrete, isolated film segments.
2Reliability
If continuous organic layers are used across the entire substrate, then complete coverage is achieved, but encapsulation efficiency decreases
Solution Approach 1:
The patent segments the organic film coverage to exclude inter-pixel regions, creating discrete covered areas that correspond to functional pixel regions. This segmentation enables effective encapsulation by isolating the organic layers from environmental exposure in non-functional areas, improving overall encapsulation quality while maintaining necessary coverage in active regions.
3Manufacturing precision
If organic thin film is deposited over the entire substrate including inter-pixel regions, then uniform deposition is achieved, but mechanical stress increases
Solution Approach 1:
The patent implements segmentation by restricting organic film deposition to discrete pixel regions rather than continuous coverage. This creates isolated film segments that cannot transmit mechanical stress across the entire substrate, thereby reducing overall mechanical stress while maintaining deposition uniformity within each segmented region through controlled deposition processes.
4Reliability
If patterned organic layers are used to reduce defects, then reliability improves, but manufacturing complexity increases
Solution Approach 1:
The patent replaces conventional mechanical photomask-based patterning methods with organic vapor jet printing technology. This substitution eliminates the need for complex mask alignment and physical contact processes, enabling direct digital patterning of organic layers with reduced mechanical complexity while achieving the desired defect reduction through precise spatial control of deposition.
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 enables the production of flexible and transparent OLEDs with improved durability, reduced defects, and enhanced performance by minimizing mechanical stress and optimizing encapsulation, while allowing for efficient electrical connections and uniform brightness across the display.
Implementation Method 1
The use of organic vapor jet printing (OVJP) to create a substrate with repeating unit areas and discontinuous organic layers
Implementation Method 2
OLEDs make use of thin organic films that emit light when voltage is applied across the device
Data Source
AI summary
Embodiments of the disclosed subject matter provide a device having a substrate, and a plurality of unit areas of an organic light emitting diode (OLED) display disposed on the substrate. The unit areas may be repeating, area-filling subdivisions on the substrate that each have an anode and a cathode. The organic film may be disposed over portions of the device other than the unit areas. The device may include at least one pixel having a plurality of sub-pixels disposed within each of the plurality of unit areas. The cathode of at least one pixel of each of the plurality of unit areas may be a common cathode.