OLED Encapsulation via Selective ALD and Organic Defining Film
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Solution Overview
Problem
Current OLED encapsulation methods for flexible devices face challenges in removing atomic layer deposition masks and incurring high production costs due to the difficulty in cleaning alumina films, which are essential for effective water and oxygen barrier formation.
Innovation Solution
The method involves forming an organic defining film around the OLED device using ink-jet printing, followed by atomic layer deposition to create an inorganic film, and then removing the organic film using oxygen plasma to achieve selective ALD without a mask, allowing for the formation of a package film with alternating inorganic and organic layers for effective encapsulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a metal mask is used for patternizing in ALD processes, then the encapsulation precision is improved, but the device complexity and production cost increase due to mask cleaning and replacement requirements
Solution Approach 1:
The patent removes the metal mask from the ALD process by using a polymer-based self-aligned deposition approach. The polymer layer is deposited first, then ALD is performed without a mask, allowing selective deposition through the polymer's physical properties rather than requiring mask fabrication, cleaning, and replacement operations.
Solution Approach 2:
The patent introduces a polymer layer as an intermediary material that enables selective ALD deposition. This polymer mediator allows the ALD process to deposit material selectively in certain regions without requiring a metal mask, thereby simplifying the overall process while maintaining encapsulation precision.
2Manufacturing precision
If wet etching is used to clean the mask, then the encapsulation precision is maintained, but the productivity decreases due to mask life span reduction and increased production cost
Solution Approach 1:
The patent eliminates the mask cleaning step entirely by removing the metal mask from the process. Instead of using wet etching to clean masks, the invention uses a maskless ALD approach where selectivity is achieved through polymer-based methods, thereby avoiding mask life span issues and associated cleaning costs.
Solution Approach 2:
The patent replaces expensive, reusable metal masks with a disposable polymer layer that is deposited fresh for each process run. This polymer layer serves the same function as a mask but can be easily removed or degraded after use, eliminating the need for costly mask maintenance and replacement operations.
3Ease of manufacture
If plasma is used to remove the polymer, then the ease of manufacture is improved, but the manufacturing precision may be affected by potential damage to underlying layers
Solution Approach 1:
The patent applies plasma treatment with controlled local quality by adjusting plasma parameters (power, time, gas flow) to selectively remove the polymer layer without affecting the underlying sensitive OLED structures. The plasma process is optimized to have different etching rates for the polymer versus the underlying inorganic and organic layers, ensuring selective removal while preserving layer integrity.
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 process, reduces costs, and provides a robust encapsulation that effectively blocks external water and oxygen, meeting the requirements for flexible OLED panels while avoiding mask-related issues.
Implementation Method 1
removing the organic defining film by using oxygen plasma
Implementation Method 2
removing the organic defining film by using oxygen plasma
Implementation Method 3
performing atomic layer disposition on the substrate and the OLED device to obtain a layer of inorganic film
Data Source
AI summary
The invention provides a encapsulation method for OLED panel, by forming an organic defining film surrounding the OLED device on the substrate, then using ALD process to form an inorganic film on the substrate and OLED device covering the package region and then removing the organic defining film to obtain an ALD film corresponding to the above of the package region, and finally forming a package film on ALD film corresponding to the above of the package region complete encapsulation the OLED panel. The present invention uses an organic defining film to realize selective atomic layer deposition, thereby avoiding using the atomic layer deposition mask and related cleaning and replacement problems. The process is relatively simple, thus saving costs, and the resulted package structure meets the encapsulation requirements of flexible OLED panel, able to effectively block the external water oxygen to protect the OLED device.