OLED Masking for Individual Addressability and Damage Prevention
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Solution Overview
Problem
The manufacturing process for OLED devices with individually addressable areas often results in micro damages and short circuits due to overlapping masks, which can lead to visual damages and reduced efficiency in light emission.
Innovation Solution
A light emitting device with a substrate and multiple active layers and electrode layers, where each layer is deposited using a specific masking process to form distinct active areas, allowing for extended electrode coverage and individual addressability of each area, thereby preventing mask-induced damages and improving homogeneity and current distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If masks are used to deposit organic OLED material and cathode material in individually addressable areas, then individual addressability is achieved, but mask overlapping or touching causes micro damages and short circuits
Solution Approach 1:
The patent introduces an intermediary masking layer that extends beyond the active area boundaries. This extended mask acts as a mediator that prevents direct contact between deposition masks and previously deposited layers, eliminating micro damages and short circuits while maintaining individual addressability of display areas.
Solution Approach 2:
The masking layer is deposited in advance before the cathode material deposition. By preparing the extended mask beforehand, the patent prevents mask-induced damages during subsequent deposition processes, ensuring reliable device manufacturing without compromising addressability.
2Manufacturing precision
If masks are used to coat only the light emitting areas, then precise patterning is achieved, but mask contact with deposited layers causes visual damages
Solution Approach 1:
The extended masking layer serves as a protective intermediary between the deposition mask and the previously deposited organic layers. It enables precise patterning of cathode material while preventing direct mask contact that would cause visual damages to the underlying layers.
Solution Approach 2:
The patent deposits a masking layer that extends beyond the active area boundaries before cathode deposition. This creates a protective cushion that absorbs the mechanical contact stress during mask deposition, preventing visual damages to the precise patterns already formed in previous layers.
3Manufacturing precision
If cathode layer is coated only on light emitting area, then precise light emission control is achieved, but sheet resistance increases and current distribution worsens
Solution Approach 1:
The patent segments the cathode structure into two functional parts: a patterned cathode over the active area for precise light emission control, and an extended cathode region beyond the active area for improved electrical performance. This segmentation allows simultaneous achievement of emission precision and current distribution reliability.
Solution Approach 2:
The extended cathode layer serves multiple functions: it maintains precise light emission control over the active area while simultaneously providing enhanced electrical conductivity and improved current distribution across the device. This multi-functionality resolves the contradiction between precision and reliability.
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 enhances manufacturing yield, reduces visual damages and short circuits, and improves light emission homogeneity by allowing larger cathode coverage, resulting in better current distribution and reduced sheet resistance.
Implementation Method 1
depositing a first organic layer forming a first active area (10) on top of said substrate (12) by using a first masking process; depositing a first electrode layer (20; 50) overcoating said first active area (10) by using a second masking process
Data Source
AI summary
The present invention relates to a light emitting device with at least two active areas and a more robust method of manufacturing such a device, wherein a first electrode layer (20) is deposited through a mask overcoating an active material (10). A second active material (30) is deposited through another mask in such a way that an area which covers and extends beyond the first electrode layer (20) is overcoated with the organic material. Then, a second electrode layer (40) is coated through a mask such that it overcoats the whole second active material (30).