OLED Spacer Segmentation for Mask Alignment
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Solution Overview
Problem
In organic light emitting displays (OLEDs), the separation regions of odd and even spacers are not differentiated, leading to issues where the fine metal mask gets caught during the patterning process, causing defects such as cathode electrode shorting due to step differences between spacers.
Innovation Solution
The OLED design incorporates odd and even spacers with distinct separation regions, where the odd separation regions are formed in different columns than the even separation regions, preventing the fine metal mask slits from being caught and reducing the likelihood of cathode electrode shorting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If spacers are integrated without being separated from each other, then manufacturing is simplified, but cathode electrode shorting occurs due to step differences between spacers
Solution Approach 1:
The spacers are segmented into separate individual spacers rather than being integrated as a single continuous structure. This segmentation allows each spacer to be independently positioned and prevents step differences that cause cathode electrode shorting, while still maintaining the structural support function.
Solution Approach 2:
A separate spacer layer is introduced as an intermediary element between the pixel define layer and the cathode electrode. This intermediary layer fills gaps and levelizes the surface, preventing direct contact between cathode electrodes on adjacent spacers and eliminating shorting paths.
2Reliability
If spacers are separated from each other, then cathode electrode shorting is prevented, but the fine metal mask gets caught in the separation regions during patterning
Solution Approach 1:
The separation regions between spacers are designed with specific local characteristics - they are positioned and sized to provide adequate spacing that prevents mask entanglement. The local geometry of separation regions is optimized to allow mask slits to pass through without being caught, while still maintaining spacer separation for reliability.
Solution Approach 2:
The spacer separation structure is predetermined and pre-formed before the fine metal mask patterning process. This preliminary arrangement of spacers with controlled separation regions ensures that when the mask is applied, the slits can move freely without being caught, as the separation regions are already optimized for mask passage.
3Ease of manufacture
If uniform spacer structure is used, then manufacturing is simplified, but endurance against external shocks is reduced
Solution Approach 1:
The spacers are designed with asymmetric or varied structures rather than uniform identical structures. Different spacer configurations (varying heights, positions, or dimensions) are used to create a more resilient structure that can better absorb and distribute external shock forces, improving overall durability while maintaining manufacturability through standardized fabrication processes.
Data Source
AI summary
Disclosed is an OLED in which separation regions of spacers in odd and even rows are formed so that a fine metal mask (FMM) between light emission layers may move without being caught in the spacers. The OLED includes even and odd spacers protruding upwardly between light emission layers and are separated by separation regions. The separation regions of each row of spacers is aligned with spacers of adjacent rows and are not aligned with the separation regions of the adjacent rows.