OLED Encapsulation with Side-Contact Contour
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Solution Overview
Problem
Existing organic light-emitting diode (OLED) devices face challenges due to sensitivity to oxygen and water, requiring careful sealing with gaps that increase manufacturing complexity and device depth, and are prone to shorts during electrical connection.
Innovation Solution
An electroluminescent device with a closed contour encapsulation means that eliminates gaps between the substrate and the counter electrode, using a non-conductive encapsulation layer to prevent moisture and oxygen ingress and facilitate electrical connection without getters, allowing for a three-dimensional contacting scheme.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a gap is left between the substrate and the encapsulation means, then the device can be manufactured more easily, but the device depth increases and reliability decreases due to oxygen and water diffusion
Solution Approach 1:
The encapsulation means is designed to extend vertically from the substrate surface into the gap region, creating a three-dimensional structure that seals the gap from the side. This vertical extension transforms a two-dimensional sealing problem into a three-dimensional solution, allowing the encapsulation to reach the counter electrode and eliminate the gap without increasing horizontal device footprint.
Solution Approach 2:
The encapsulation means is positioned within the gap structure, nesting the sealing function inside the existing gap architecture. The encapsulation material fills and seals the gap space, effectively removing the harmful void while utilizing the available volume within the device structure.
2Reliability
If getters are added within the sealed volume, then oxygen and water diffusion is reduced, but manufacturing complexity and device depth increase
Solution Approach 1:
The invention extracts and removes the need for getters by implementing a gap-free sealed structure. Instead of adding getters to address diffusion issues, the design eliminates the root cause (the gap) through direct contact between the encapsulation means and the counter electrode, making getters unnecessary.
Solution Approach 2:
The encapsulation means is designed to extend and seal the gap before the device is fully assembled and sealed. This preliminary sealing action prevents oxygen and water diffusion from occurring in the first place, eliminating the need for subsequent getter materials to mitigate diffusion effects.
3Reliability
If the encapsulation means extends to contact the counter electrode, then the gap is eliminated and reliability improves, but the risk of electrical short increases
Solution Approach 1:
The encapsulation means serves as an intermediary material positioned between the substrate electrode and the counter electrode. It extends vertically to seal the gap while its electrically insulating properties prevent direct electrical contact, thus eliminating the gap for sealing purposes while maintaining electrical isolation through its material characteristics.
Solution Approach 2:
The encapsulation means exhibits different functional properties at different locations: at the horizontal interface with the substrate, it provides mechanical sealing; at the vertical interface with the counter electrode, it provides electrical insulation while maintaining sealing. This local differentiation of function allows simultaneous gap elimination and short prevention.
Data Source
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AI summary
This invention relates to an electroluminescent device (10) comprising an organic light emitting layer (50) and an encapsulation means (70) with a closed contour encapsulating the side of the electroluminescent layer stack (59) and for electrically contacting the counter electrode (40) to an electrical source. Furthermore, the invention relates to a method for providing such a device, the use of the contiguous contour as an encapsulation means and a covered substrate to be used in such a device.