Substrate Mask Alignment via Iterative Optical Sensing
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Solution Overview
Problem
As the size of substrates for large-sized organic electroluminescent displays increases, there is a need for a precise alignment system to prevent sagging and ensure accurate deposition of organic material layers, which existing vertical aligning systems fail to address effectively.
Innovation Solution
A device and method for aligning substrates and masks using aligning marks, a sensing unit, and a control unit to adjust the position of the substrate relative to the mask, ensuring precise alignment by iteratively correcting alignment errors until they meet predetermined criteria.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the substrate size is enlarged for large-sized display manufacture, then the display size increases, but the substrate sags during effusion and alignment precision deteriorates
Solution Approach 1:
The patent applies preliminary action by pre-positioning aligning marks on both the substrate and mask before the deposition process. The sensing unit detects these marks in advance to determine alignment status, allowing the system to identify and correct alignment errors before material deposition begins, thereby preventing sagging-related precision loss in large substrates
Solution Approach 2:
The patent implements feedback through a sensing unit that continuously monitors the alignment between substrate and mask by detecting aligning marks. The control unit receives alignment information from the sensing unit and adjusts the substrate or mask position accordingly, creating a closed-loop control system that maintains alignment precision even for enlarged substrates
2Stability of the object's composition
If a vertical aligning system is used to prevent substrate sagging, then substrate stability improves, but alignment accuracy between substrate and mask deteriorates
Solution Approach 1:
The patent replaces purely mechanical alignment methods with an optical sensing system. The sensing unit uses optical detection of aligning marks to determine alignment status, substituting mechanical adjustment alone with a combination of optical detection and controlled mechanical correction, thereby achieving both stability and precision
Solution Approach 2:
The patent introduces aligning marks as an intermediary element between the substrate and mask. These marks serve as reference points that the sensing unit detects to mediate the alignment process, enabling precise alignment measurement and correction without direct mechanical contact that could compromise stability
Data Source
AI summary
A device for aligning a substrate and a mask, and a method using the same, where the device includes aligning marks in unused portions of the substrate and the mask, a sensing unit for determining overlap of the aligning marks when the substrate is aligned with the mask, and a control unit for controlling an aligning process to be repeated on the basis of data sensed and determined by the sensing unit. The sensing unit may include a camera positioned in photographic range to determine any alignment error in the alignment marks. According to another embodiment of the present invention, the alignment error between the substrate and the mask is sensed to determine whether it is acceptable or not. When the alignment error is unacceptable, the operations for aligning the substrate with the mask are repeated until the alignment error is acceptable.