Organic Light Emitting Device Film Edge Geometry
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Solution Overview
Problem
Existing organic light emitting devices face challenges in achieving high precision in forming organic compound layers and ensuring electrical connections due to issues with vacuum vapor deposition using metal masks, which result in low-definition displays and potential electrical disconnection, as well as exposure of the organic compound layer to the environment leading to deterioration.
Innovation Solution
The organic light emitting device incorporates a substrate with a lower electrode, an organic compound layer, and an upper electrode, where the organic compound layer covers the lower electrode and the upper electrode covers the organic compound layer, with specific angle and thickness requirements for the film ends to ensure secure electrical connection and minimize frame region width, using photolithography to pattern the layers and a sealing layer to protect against environmental exposure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If vacuum vapor deposition using a metal mask is used to form organic compound layers, then the manufacturing process is simple, but the alignment precision and film forming precision are low
Solution Approach 1:
The patent replaces the mechanical vacuum vapor deposition method with a photolithography-based chemical deposition method. Instead of using physical masks and vapor deposition, the organic compound layers are formed by photopatternable precursors that are chemically transformed into the final organic layers through light exposure and thermal processing, achieving high precision without complex mechanical alignment
Solution Approach 2:
The patent uses photomasks to create optical copies of the desired pattern, which are then transferred to the photoresist and organic precursor layers through photolithography. This optical copying method achieves high precision pattern transfer without the alignment issues of mechanical mask alignment in vacuum deposition
2Manufacturing precision
If photolithography is used to pattern organic compound layers without metal masks, then alignment precision and film forming precision are improved, but the ends of the film are exposed to the external environment causing deterioration
Solution Approach 1:
The patent forms an upper electrode layer over the entire substrate before patterning, so that the electrode layer is already in place to protect the organic compound layers from environmental exposure. This preliminary action ensures that when the organic layers are patterned, their ends are covered by the electrode layer rather than being exposed to deterioration
Solution Approach 2:
The patent creates a nested structure where the organic compound layers are embedded within and covered by the upper electrode layer. The electrode layer acts as a protective outer shell that encloses the organic layers, preventing direct exposure to environmental factors like moisture and oxygen
3Manufacturing precision
If photolithography patterns organic compound layers and upper electrode layer, then manufacturing precision is improved, but electrical connection to organic light emitting elements may fail
Solution Approach 1:
The patent forms the upper electrode layer over the entire substrate before patterning, ensuring that continuous electrode material is deposited across the whole surface. This preliminary complete coverage ensures that even after photolithographic patterning, the electrode maintains sufficient continuity and connection pathways to the feeding pad portions, preventing electrical connection failures
4Ease of manufacture
If metal masks are used in vacuum vapor deposition, then the process is simple, but the frame region width increases due to non-effective regions at mask edges
Solution Approach 1:
The patent replaces mechanical mask-based deposition with photolithographic patterning of precursors, which allows for precise definition of the organic compound layer boundaries. This eliminates the gradual thickness transition at mask edges, enabling the frame region to be minimized to the exact dimensions needed without non-effective transition zones
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 secures reliable electrical connections and reduces the frame region width, enhancing the precision and durability of the organic light emitting device while preventing deterioration from environmental exposure.
Implementation Method 1
Vacuum vapor deposition using a metal mask is widely employed as a method of forming an organic compound layer and an upper electrode
Implementation Method 2
Organic light emitting elements each include a pair of electrodes and an organic emission layer interposed between the pair of electrodes
Data Source
AI summary
Provided is an organic light emitting device, including: a lower electrode; an upper electrode and a substrate having an electrode pad portion, in which when an angle formed by a slant in section of a film end in a region between the lower electrode and the electrode pad portion and a surface of the substrate is given as θ1, Formula (1) and Formula (2) are satisfied; and when an angle formed by a slant in section of a film end in at least a part of other regions than the region between the lower electrode and the electrode pad portion and the surface of the substrate is given as θ3, Formula (3) and Formula (4) are satisfied.tan(θ1)=d1/d2 (1)tan(θ1)<0.2 (2)tan(θ3)=d3/d4 (3)tan(θ3)≧0.2 (4)