Organic EL Device Electrode Structure for Aperture Ratio
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Solution Overview
Problem
The manufacturing process of organic EL light emitting devices often results in a low aperture ratio due to roughened surfaces and short circuits, leading to decreased luminous flux and increased costs, especially when used in panel or curved surface applications.
Innovation Solution
A simplified manufacturing method involving the formation of transparent electrode films without gaps, with separate layers for positive and negative electrode contact portions, and the use of protective and insulating layers to prevent short circuits and enhance aperture ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a transparent conductive electrode film (ITO) is used and etching treatment is performed during manufacturing, then the electrode can be formed and connected, but the surface and edges of ITO become roughened leading to short circuits and device failure
Solution Approach 1:
The patent extracts the problematic etching treatment step from the manufacturing process. By forming electrode patterns through deposition without subsequent etching, the roughening of ITO surfaces and edges is eliminated, preventing short circuits while maintaining ease of manufacture.
Solution Approach 2:
The patent applies prior cushioning by forming a protective insulating film covering the electrode patterns before final assembly. This insulating film prevents direct contact between adjacent electrodes, cushioning against potential short circuits that could occur during handling or operation.
2Reliability
If electrode takeoff portions are formed on each side of the panel to enable voltage application, then stable voltage can be applied, but the aperture ratio decreases leading to reduced luminous flux
Solution Approach 1:
The patent transitions from a two-dimensional planar electrode arrangement to a three-dimensional stacked structure. By forming positive and negative electrode contact portions in different layers (different dimensions), stable voltage application is achieved without requiring large lateral takeoff portions that would reduce aperture ratio.
Solution Approach 2:
The patent segments the electrode structure into distinct positive electrode contact portions and negative electrode contact portions located in different layers. This segmentation allows each electrode type to have its own dedicated contact area, enabling stable voltage application while minimizing the overall footprint and maximizing aperture ratio.
3Reliability
If a complex manufacturing process with multiple layers (transparent conductive electrode film, electrode, interlayer insulating film, photosensitive organic insulator) is used, then reliable device structure can be achieved, but manufacturing cost increases significantly
Solution Approach 1:
The patent merges multiple functions into fewer layers. The insulating film serves both as an electrical insulator and as a structural support layer, while electrode patterns are formed directly during deposition without separate patterning steps. This merging reduces manufacturing complexity while maintaining device reliability.
Solution Approach 2:
The patent implements multi-functionality where the insulating film performs multiple roles: electrical insulation, mechanical support, and process simplification. The electrode patterns formed during deposition serve both as conductive elements and as alignment references for subsequent layers, reducing the need for separate processing steps.
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 method increases the aperture ratio, reduces the number of process steps, prevents short circuits, and enhances luminous flux while maintaining reliability and cost-effectiveness.
Implementation Method 1
An organic EL light emitting device comprises a substrate, a transparent electrode film (positive electrode film), a positive electrode contact and power supplying portion, a negative electrode contact and power supplying portion, an auxiliary electrode, an insulating layer, an organic light emitting layer, and a negative electrode film
Data Source
Figure 1A~1F
Figure 2~3B
Figure 4A~4F
AI summary
An organic EL light emitting device (100) comprises a transparent substrate (1), a transparent electrode film (2) formed on the substrate (1), a positive electrode contact portion (4) in contact with a part of the transparent electrode film (2) and electrically connected therewith, an insulating layer (7) formed on the transparent electrode film (2) such that the an insulating layer (7) covers a portion excluding a light emitting part, an organic light emitting layer (8) formed on the transparent electrode film (2) and on the insulating layer (7), a negative electrode film (9) formed on the organic light emitting layer (8), a negative electrode contact portion (5) in contact with at least a part of the negative electrode film (9) and electrically connected therewith, and a protective layer (3) for separating and electrically insulating the positive electrode contact portion (4) and the transparent electrode film (2) from the negative electrode contact portion (5). The transparent electrode film (2) is formed without a gap across an area including areas where the protective layer (3), the positive electrode contact portion (4), the negative electrode contact portion (5), the insulating layer (7), the organic light emitting layer (8) and the negative electrode film (9) are formed.