OLED Packaging with Copper Film and Hydrogen Sealing
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Solution Overview
Problem
OLED displays have a short operational life due to sensitivity to water vapor and oxygen, which causes degradation, and the use of low work function metals in cathodes leads to oxidation and further reduction in device life.
Innovation Solution
A packaging method for OLED displays involving the formation of a copper film layer on a substrate, a desiccant layer inside a frame sealant on another substrate, and sealing them in a vacuum with hydrogen, where the copper film reacts with oxygen to form CuO, which is reduced to Cu and absorbed by the desiccant, preventing water and oxygen damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a low work function metal is used in the cathode to reduce electron injection barrier, then the electron injection efficiency is improved, but the device life is decreased due to oxidation of the metal
Solution Approach 1:
A copper layer is introduced as an intermediary between the low work function metal cathode and the OLED layer. This copper layer serves as a protective barrier that prevents oxidation of the reactive metal while maintaining electron injection efficiency. The copper layer is formed by evaporation in a vacuum environment and is subsequently protected by a desiccant layer.
Solution Approach 2:
The device is packaged in a vacuum environment (0.1-10 Pa) filled with hydrogen gas, creating an inert atmosphere that prevents oxidation of the copper layer and other metal components. This inert environment significantly extends device life by eliminating oxygen exposure.
2Ease of manufacture
If the OLED is exposed to water vapor and oxygen, then the manufacturing process is simplified, but the organic thin film degrades rapidly causing short operation life
Solution Approach 1:
The OLED device is hermetically sealed in a vacuum package filled with hydrogen gas, creating an inert atmosphere that prevents water vapor and oxygen from reaching the organic thin film. This inert environment protects the sensitive OLED materials from degradation while allowing for relatively simple manufacturing processes.
Solution Approach 2:
A desiccant layer is incorporated into the packaging structure to actively absorb and remove any trace amounts of water vapor that may be present in the vacuum package. This extraction of harmful substances (water and oxygen) from the internal environment ensures long-term stability of the OLED.
3Duration of action of stationary object
If a vacuum packaging method is used to protect OLED from water and oxygen, then the device life is extended, but the packaging process complexity increases
Solution Approach 1:
The copper layer formation, desiccant layer deposition, and vacuum packaging processes are merged into a single integrated manufacturing step. The entire packaging structure is formed in one vacuum evaporation process, reducing the number of separate manufacturing steps and simplifying the overall packaging process while maintaining extended device life.
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 method significantly extends the operational life of OLED displays by effectively removing oxygen and absorbing water vapor, protecting the OLED layer from degradation.
Implementation Method 1
when O2 enters inside the OLED display device, Cu in the copper layer will react with the O2 to produce CuO so as to remove the O2
Implementation Method 2
When OLED display device emits light and generates heat, the CuO is reduced to Cu and produces H2O
Implementation Method 3
the produced H2O can be absorbed by desiccant in the desiccant layer in order to prevent water and oxygen from damaging the OLED layer
Implementation Method 4
curing the frame sealant in order to seal hydrogen between the copper film layer and the second substrate
Implementation Method 5
forming a copper film layer on an OLED layer of a first substrate through an evaporation method
Data Source
AI summary
An OLED display and a packaging method for the same are disclosed. The method includes: forming a copper film layer on an OLED layer of a first substrate; forming a frame sealant at an outer peripheral edge of a second substrate; in a vacuum machine filled with hydrogen, pressing and bonding the first substrate and the second substrate; curing the frame sealant in order to seal hydrogen between the copper film layer and the second substrate. The OLED display includes a first substrate, a copper film layer, a desiccant layer and a second substrate. Hydrogen is filled between the copper film layer and the second substrate. The present invention can effectively increase the packaging effect and extends the operation life of the OLED display.