OLED Array Transfer Printing Reduces Evaporation Complexity
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Solution Overview
Problem
Conventional methods for producing organic light emitting diode (OLED) arrays are complex and costly due to the need for vacuum evaporation and high-temperature processes, which complicate the formation of organic light emitting layers.
Innovation Solution
The method involves creating OLED arrays with a base having convexities, where organic light emitting diodes are formed using transfer printing for layers like the hole injection, hole transport, and electroluminescent layers, while electron transport and injection layers are made by vacuum evaporation, reducing the complexity and cost by utilizing a combination of printing and evaporation techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If vacuum evaporation is used to form the organic light emitting layer, then the layer formation precision is improved, but the device complexity and manufacturing cost increase
Solution Approach 1:
The patent divides the organic light emitting layer formation process into multiple stages: first forming the hole injection layer and hole transport layer by vacuum evaporation, then forming the electroluminescent layer by solution processing, and finally forming the electron transport layer and electron injection layer by vacuum evaporation. This segmentation allows different deposition methods to be used for different layers, reducing overall process complexity while maintaining precision where needed.
Solution Approach 2:
The patent applies different material properties and deposition methods to different regions/layers of the OLED structure. The hole injection layer, hole transport layer, electron transport layer, and electron injection layer are formed with specific material compositions and thicknesses optimized for their respective functions, while the electroluminescent layer uses solution processing for better uniformity. This local optimization resolves the contradiction by applying high-precision vacuum evaporation only where critical.
2Manufacturing precision
If vacuum evaporation is used for organic light emitting layer formation, then the layer quality is improved, but the manufacturing cost increases
Solution Approach 1:
The patent segments the organic light emitting layer formation into multiple sub-layers (hole injection layer, hole transport layer, electroluminescent layer, electron transport layer, electron injection layer) with different formation methods. The electroluminescent layer, which is the most critical for light emission quality, is formed by solution processing to reduce cost, while the transport layers use vacuum evaporation for adequate quality at lower cost than full vacuum evaporation.
Solution Approach 2:
The patent uses solution processing methods (spin coating, dip coating, or inkjet printing) to form the electroluminescent layer, which can be done at lower cost than vacuum evaporation. The solution is deposited and then dried to form a uniform layer, copying the functional requirements of vacuum-evaporated layers but using cheaper manufacturing techniques.
3Manufacturing precision
If high temperature processes are used, then the organic light emitting layer formation is improved, but the energy consumption and process complexity increase
Solution Approach 1:
The patent changes the formation parameters of different layers: the hole injection layer and hole transport layer are formed by vacuum evaporation at relatively low temperatures, the electroluminescent layer is formed by solution processing at low temperatures followed by low-temperature drying, and the electron transport layer and electron injection layer are formed by vacuum evaporation. This parameter optimization reduces energy consumption while maintaining layer quality.
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 simplifies the production process, reduces costs, and enhances the efficiency of OLED array manufacturing by leveraging transfer printing for certain layers, while maintaining the necessary precision and performance through vacuum evaporation for critical layers.
Implementation Method 1
The organic light emitting layer is formed usually by vacuum evaporation which needs mask, high temperature, and vacuum device
Data Source
AI summary
The disclosure relates to an organic light emitting diode array. The organic light emitting diode array includes a number of thin-film transistors arranged to form an array, a first insulative layer, a plurality of first electrodes, a number of electroluminescent layers, a patterned second insulative layer, and at least one second electrode. The first insulative layer is located on the plurality of first electrodes defines a number of convexities. The first electrodes are located on the convexities and electrically connected to the thin-film transistors. The electroluminescent layers are located on the first electrodes. The patterned second insulative layer is located on the first insulative layer to cover the first electrodes and expose the electroluminescent layers. The at least one second electrode is electrically connected to the electroluminescent layers.