OLED Fabrication via Joule Heat Transfer Maskless Patterning
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Solution Overview
Problem
Existing methods for fabricating organic light emitting diode (OLED) displays face challenges in precisely patterning light emission layers for larger areas and high definition, as well as increasing process time and chamber size due to the limitations of thermal evaporation methods using metal masks.
Innovation Solution
A method involving the formation of a metal pattern on a donor substrate, which generates Joule heat to sublimate and transfer organic light emission material to an acceptor substrate, eliminating the need for a metal mask and allowing for precise patterning under vacuum or inert gas, with the use of spacers to prevent color mixing and reduce chamber size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the substrate size is increased, then the display area is improved, but the metal mask becomes increasingly bent and patterning precision deteriorates
Solution Approach 1:
The invention extracts and eliminates the metal mask from the deposition system. By using a shadow mask made of a flexible material that can be conformally attached to the substrate, the rigid metal mask is removed, solving the bending and precision issues while enabling large area substrates to be processed without compromising patterning accuracy.
Solution Approach 2:
The invention employs a flexible shadow mask made of a thin film material that can conformally attach to large area substrates. This flexible mask eliminates the bending problems associated with rigid metal masks and maintains patterning precision across large substrate areas through conformal attachment.
2Stability of the object's composition
If the distance between the boat and substrate is increased, then uniformity of light emission layer is improved, but the chamber size and process time are increased
Solution Approach 1:
The invention introduces dynamic control of the deposition process by enabling independent movement and positioning of the shadow mask relative to the substrate. This dynamic adjustment allows optimization of deposition uniformity without requiring increased distance, thereby reducing chamber size and process time while maintaining light emission layer uniformity.
Solution Approach 2:
The shadow mask is pre-attached to the substrate in a conformal manner before the deposition process begins. This preliminary action ensures proper positioning and geometry are established upfront, allowing deposition to proceed efficiently at optimized distances that reduce both chamber size and process time while maintaining uniformity.
3Stability of the object's composition
If the distance between the boat and substrate is increased, then uniformity of light emission layer is improved, but the chamber size is increased
Solution Approach 1:
The dynamic positioning capability of the shadow mask allows optimization of the deposition geometry, enabling uniform light emission layer formation at reduced distances. This eliminates the need for large chamber volumes while maintaining deposition uniformity through controlled, adjustable mask-substrate positioning.
Solution Approach 2:
By pre-attaching the shadow mask conformally to the substrate, the optimal deposition geometry is established before deposition begins. This preliminary configuration enables efficient deposition at reduced distances, minimizing chamber size requirements while ensuring uniform light emission layer formation.
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 precise patterning of light emission layers for larger areas and high definition, reduces process time, and minimizes the chamber size required for forming the light emission layer, improving throughput and accuracy.
Implementation Method 1
an instantaneous voltage/current is applied to the metal pattern of the donor substrate to generate Joule heat
Implementation Method 2
to sublimate the organic light emission material formed on the donor substrate so as to be transferred to the acceptor substrate
Data Source
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AI summary
A method of fabricating an organic light emitting diode display device includes: sequentially forming a thin film transistor (TFT) array (102), the first electrode (104), a bank pattern (106), a spacer (112), and the first relevant layer (108a) on an acceptor substrate (100); sequentially forming a metal pattern (202) and an organic light emission material layer on a donor substrate (200); aligning and attaching the acceptor substrate (100) and the donor substrate (200), and forming the light emission layer (108b) by transferring the organic light emission material onto the acceptor substrate (100) by applying power to the metal pattern (202); and sequentially forming the second relevant layer (108c) and the second electrode (110) on the light emission layer-formed acceptor substrate.