Multilayer Printing Alignment via Image Subtraction
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Solution Overview
Problem
The challenge in solar cell manufacturing lies in accurately aligning and controlling the deposition of multilayer patterns on substrates during the printing process, particularly in screen printing, which often results in misalignment and defects due to the complexity of aligning successive layers with high precision, leading to reduced device efficiency and increased costs.
Innovation Solution
A method and apparatus utilizing a closed-loop control system that acquires optical images of printed layers, performs image subtraction to determine precise alignment, and adjusts subsequent printing operations, enabling real-time feedback for improved alignment and quality control without the need for dedicated vision systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional screen printing processes are used for multilayer pattern deposition, then manufacturing simplicity is maintained, but alignment precision deteriorates leading to misalignment and defects
Solution Approach 1:
The patent applies preliminary action by performing alignment verification through image acquisition and subtraction analysis before completing the printing process. The system captures images of previously printed layers, performs subtraction to identify misalignment, and adjusts subsequent printing operations proactively to prevent defects rather than detecting them after occurrence.
Solution Approach 2:
The patent implements feedback control by using image subtraction results to generate alignment error signals that are fed back to the printing system. This closed-loop feedback mechanism continuously monitors layer alignment and dynamically adjusts printing parameters to maintain precision, transforming the open-loop conventional printing process into a controlled system.
2Adaptability or versatility
If multiple successive printing operations are performed to create multilayer patterns, then functional complexity is improved, but alignment control deteriorates due to cumulative positioning errors
Solution Approach 1:
The patent applies feedback control by using image subtraction results to generate alignment error signals that are fed back to the printing system. This closed-loop feedback mechanism continuously monitors layer alignment and dynamically adjusts printing parameters to maintain precision, transforming the open-loop conventional printing process into a controlled system.
Solution Approach 2:
The patent applies preliminary action by performing alignment verification through image acquisition and subtraction analysis before completing the printing process. The system captures images of previously printed layers, performs subtraction to identify misalignment, and adjusts subsequent printing operations proactively to prevent defects rather than detecting them after occurrence.
3Measurement precision
If dedicated vision systems are implemented for alignment verification, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent applies universality by making the existing optical detection system serve multiple functions: it is used both for process monitoring and for alignment verification through image subtraction. This eliminates the need for dedicated vision systems, as the same optical infrastructure performs both manufacturing and measurement tasks, reducing device complexity and cost.
Solution Approach 2:
The patent applies self-service by enabling the printing system to perform its own alignment verification using its existing optical detection capabilities. The system captures images, performs subtraction analysis, and adjusts alignment without requiring external dedicated vision systems, making the system self-sufficient for both production and quality control.
Data Source
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AI summary
The present invention provides a control method and apparatus for printing a multilayer pattern on a substrate. In one embodiment, a method for printing a multilayer pattern includes a first printing operation comprising depositing a first patterned layer on a region of a surface of the substrate, a second printing operation comprising depositing a second patterned layer over the region of the surface or first patterned layer, and verifying the precision of the alignment of the second patterned layer relative to the first patterned layer. Verifying comprises acquiring a first optical image of the first patterned layer after the first printing operation, acquiring a second optical image of the second patterned layer after the second printing operation, and determining the position of the second patterned layer by performing an image subtraction process to form a first subtracted optical image and comparing the subtracted optical image with the first image.