OLED Encapsulation Planar Surface Oxygen Barrier
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Solution Overview
Problem
OLED structures face limited lifetime due to material degradation and the formation of non-emissive dark spots caused by moisture and oxygen ingress, leading to decreased electroluminescence efficiency and increased drive voltage.
Innovation Solution
An encapsulating layer is deposited over the OLED structure with a substantially planar surface to fully enclose it, reducing oxygen penetration and preventing material degradation, which includes methods such as inkjet deposition of organic materials like acrylate, methacrylate, and acrylic acid mixtures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the OLED structure is exposed to ambient atmosphere during manufacturing, then the manufacturing process is simpler and faster, but moisture and oxygen ingress causes material degradation and dark spot formation
Solution Approach 1:
The patent applies preliminary action by depositing the encapsulating layer immediately after the OLED structure is formed, before the device is exposed to ambient atmosphere. This prevents moisture and oxygen ingress from occurring in the first place, rather than attempting to repair damage after it happens. The encapsulating layer is deposited as the next sequential step in the manufacturing process, creating a protective barrier before degradation can occur.
Solution Approach 2:
The patent uses a thin film encapsulating layer deposited over the entire OLED structure to provide protection against moisture and oxygen. This thin film approach allows protection without significantly increasing device thickness or complexity, and enables continuous deposition that covers all surfaces including edges and interfaces where degradation is most likely to occur.
2Ease of manufacture
If a non-planar encapsulating layer is deposited, then the deposition process is simpler, but subsequent layers cannot be evenly deposited and device performance deteriorates
Solution Approach 1:
The patent applies preliminary action by depositing the encapsulating layer with planarization properties as part of the initial encapsulation step. This layer serves dual purposes: providing the moisture and oxygen barrier while simultaneously creating a planar surface. Subsequent layers are then deposited over this planar surface, ensuring uniform thickness and performance without requiring additional planarization steps.
Solution Approach 2:
The patent changes the physical or chemical parameters of the encapsulating layer to achieve planarity. By selecting materials and deposition conditions that produce a planar surface (such as using spin-coating followed by curing, or using specific deposition parameters), the encapsulating layer simultaneously provides protection and creates a uniform surface for subsequent layers.
3Device complexity
If the encapsulating layer does not fully enclose the OLED structure, then the deposition process is simpler, but oxygen penetration occurs at interfaces and degradation occurs
Solution Approach 1:
The patent uses a thin film encapsulating layer that completely covers the OLED structure including all edges and interfaces. This continuous film approach ensures that no gaps or openings remain where oxygen and moisture could penetrate. The layer is deposited to extend beyond the boundaries of the OLED structure, creating a complete enclosure that protects all vulnerable interfaces.
Solution Approach 2:
The patent extends the encapsulating layer in multiple dimensions to ensure complete coverage. The layer not only covers the top surface but also extends down the sidewalls and covers the edges of the OLED structure. This multi-dimensional coverage approach ensures that oxygen and moisture cannot penetrate through edges or interfaces, providing comprehensive protection.
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
The encapsulating layer increases the OLED structure's lifetime by preventing oxygen penetration, reducing dark spot formation, and ensuring uniform deposition of subsequent layers, thereby enhancing the device's performance and longevity.
Implementation Method 1
The encapsulating layer reduces any oxygen penetration into the OLED structure
Implementation Method 2
inkjet depositing an organic encapsulating layer over a substrate
Data Source
AI summary
The present invention generally relates to organic light emitting diode (OLED) structures and methods for their manufacture. To increase the lifetime of an OLED structure, an encapsulating layer may be deposited over the OLED structure. The encapsulating layer may fully enclose or “encapsulate” the OLED structure. The encapsulating layer may have a substantially planar surface opposite to the interface between the OLED structure and the encapsulating layer. The planar surface permits successive layers to be evenly deposited over the OLED structure. The encapsulating layer reduces any oxygen penetration into the OLED structure and may increase the lifetime of the OLED structure.