Flexible OLED Display Lifetime via Low-Temp Plastic Substrate
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Solution Overview
Problem
Current OLED displays on plastic substrates face challenges with high processing temperatures, leading to increased power consumption, reduced TFT performance, and shorter lifetimes due to thermal expansion mismatches and increased operating temperatures, which degrade display longevity.
Innovation Solution
The development of an active-matrix driven flexible OLED display with a phosphorescent emissive layer on a plastic substrate with a glass transition temperature less than 200°C, using organic vapor jet printing and an organic TFT backplane, which operates at a luminance of at least 500 cd/m2 with minimal luminance decay (less than 3%) after 10,000 hours, and maintains low power dissipation and controlled temperature rise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If OLED displays are fabricated on plastic substrates with high processing temperatures, then manufacturing is feasible, but device lifetime is reduced due to thermal expansion mismatches and increased operating temperatures
Solution Approach 1:
The patent applies parameter changes by selecting a plastic substrate with a glass transition temperature of less than 200°C, which is a specific parameter change from conventional higher-temperature substrates. This parameter change enables the substrate to maintain dimensional stability at operating temperatures while allowing fabrication processes to proceed without excessive thermal stress, thereby extending OLED display lifetime to over 10,000 hours at 500 cd/m2 luminance
Solution Approach 2:
The patent employs composite materials by combining a plastic substrate with a specific glass transition temperature characteristic with OLED functional layers and TFT backplane structures. This composite approach creates a thermally matched system where the substrate's thermal properties are optimized to reduce expansion mismatches with other layers, solving the contradiction between manufacturability and device lifetime
2Manufacturing precision
If processing temperatures are increased to ensure manufacturing quality, then manufacturing precision is improved, but power consumption increases and TFT performance degrades
Solution Approach 1:
The patent changes the temperature parameter by using a substrate with glass transition temperature <200°C, which allows precise control of fabrication temperatures. This enables manufacturing to be conducted at lower temperatures that prevent TFT performance degradation and reduce power consumption during operation, while still achieving high manufacturing precision through controlled low-temperature processing
3Illumination intensity
If operating temperature is increased to maintain luminance output, then brightness is maintained, but device lifetime is reduced due to thermal degradation
Solution Approach 1:
The patent applies parameter changes by utilizing the substrate's glass transition temperature characteristic to maintain structural integrity at lower operating temperatures. This enables the display to achieve 500 cd/m2 luminance output while operating at temperatures that do not cause thermal degradation, extending device lifetime to over 10,000 hours
Solution Approach 2:
The patent implements thermal management through feedback mechanisms that monitor and control operating temperature. By maintaining temperature within optimal ranges, the system preserves luminance output while preventing thermal degradation, ensuring both brightness performance and long device lifetime
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 solution extends OLED display lifetime to over 10,000 hours while maintaining high luminance and reducing power consumption, ensuring flexibility and cost-effectiveness by using lower processing temperatures and optimizing TFT properties for reduced stress and improved performance.
Implementation Method 1
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 including an active-matrix driven flexible display including a plurality of Organic Light Emitting Diodes (OLEDs) formed on a plastic substrate, where each OLED includes a phosphorescent first emissive layer, where the display operates at a luminance value of at least 500 cd/m2 with a luminance decay of not more than about 3% after 10,000 hours of operation, and where the display is formed on the plastic substrate having a glass transition temperature of the less than 200° C.