Stretchable OLED Using Nano-Fiber Transport Layers
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Solution Overview
Problem
Current methods for manufacturing stretchable OLEDs and three-dimensional tactile displays face challenges such as reduced device density, complex processes, and limited directional stretchability, with existing solutions having high driving voltage and neglecting the stretchability of key layers like the hole transport, emission, and electron transport layers.
Innovation Solution
A three-dimensional tactile display apparatus and manufacturing method that incorporates a stretchable light emitting part with a hole transport layer, emission layer, electron transport layer, and cathode formed from stretchable materials, including conductive polymer nano-fibers, metal oxide nano-particles, and nano-wire materials, allowing for deformation in multiple directions and low voltage operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the island interconnect method is used to manufacture stretchable OLEDs, then existing devices can be used as is, but the device density is lowered and the process becomes complicated
Solution Approach 1:
The patent changes the material parameters of the OLED components by using stretchable materials with elastomeric properties for the substrate, electrode, hole transport layer, emission layer, electron transport layer, and encapsulation layer. This material parameter change enables the entire device to be stretched without compromising performance, thereby increasing device density while maintaining ease of manufacture through solution processing techniques.
2Adaptability or versatility
If the mechanical buckling method is used to manufacture stretchable OLEDs, then devices can be transferred to pre-strained substrate, but it is difficult to secure large area and stretch is limited to one direction
Solution Approach 1:
The patent employs solution processing techniques to fabricate the OLED device directly on a large-area stretchable substrate. By using low-temperature solution processing, the device can be manufactured over large areas without the need for mechanical buckling or pre-strained substrates, enabling both large display area and multi-directional stretchability.
3Adaptability or versatility
If Ag nano-wire-based cathode and anode are formed on transparent polyurethane substrate, then stretchability is achieved, but driving voltage becomes very high
Solution Approach 1:
The patent uses composite material structures for the electrode and transport layers, combining stretchable conductive polymers with traditional OLED materials. The hole transport layer uses stretchable materials with good hole transport capability, and the electron transport layer uses metal oxide nano-particles in a stretchable matrix, creating composite structures that maintain low driving voltage while achieving stretchability.
4Reliability
If conventional rigid materials are used for hole transport layer, emission layer, and electron transport layer, then device performance is maintained, but stretchability cannot be achieved
Solution Approach 1:
The patent systematically changes the material parameters of all functional layers by selecting stretchable materials with appropriate electrical and optical properties. The hole transport layer uses stretchable conductive polymers, the emission layer uses flexible phosphorescent or fluorescent materials, and the electron transport layer uses metal oxide nano-particles in elastomeric matrices, maintaining transport characteristics while enabling stretchability.
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
Enables the creation of a stretchable OLED and three-dimensional tactile display with improved mechanical stability and reduced voltage requirements, achieving stable hole and electron transport characteristics while allowing for 3D deformation and large-area applications.
Implementation Method 1
a conductive polymer material into a nano-fiber structure by adding a nonionic surfactant having a predetermined mass ratio to a solution containing the conductive polymer material
Implementation Method 2
a stretchable emission layer (EML) formed on the stretchable HTL and including a light-emitting material
Implementation Method 3
a stretchable electron transport layer (ETL) formed on the stretchable EML and including metal oxide nano particles
Data Source
AI summary
Provided are an organic light emitting diode (OLED), a three-dimensional (3D) tactile display apparatus, and a manufacturing method thereof. The OLED includes a stretchable driving part including a stretchable field effect transistor (FET) and a stretchable light emitting part including a stretchable material on the stretchable driving part. The 3D tactile display apparatus includes a stretchable actuator having a driving layer formed of transparent rubber, a stretchable driving part having a stretchable FET, and a stretchable light emitting part including a stretchable material.