Screen Printing Device Optical Axis Calibration
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Solution Overview
Problem
Current screen printing devices with two imaging optical axes face challenges in achieving high precision substrate positioning due to errors in optical axis alignment and local position errors in the moving mechanism, leading to printing deviations and complex calibration processes, making it difficult to confirm positioning precision during production.
Innovation Solution
A screen printing device and method that includes an imaging unit with two imaging optical axes for recognizing marks on the substrate and mask plate, an optical axis calibration process to detect relative positions, and surface correction data creation to correct positional deviations, allowing for precise positioning and evaluation of substrate positioning precision before and during production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single imaging unit with two imaging optical axes is used to image both substrate and mask plate, then the imaging unit can be moved by a single travel unit to enable both imaging, but positional deviation occurs between coordinate systems leading to incorrect position recognition
Solution Approach 1:
The patent replaces mechanical alignment methods with an optical field-based coordinate system transformation method. By using imaging data from the two imaging optical axes and performing coordinate transformation calculations, the system compensates for mechanical positioning errors and achieves precise position recognition without complex mechanical adjustments.
Solution Approach 2:
The patent changes the parameter of coordinate system reference by establishing a transformation relationship between the two imaging optical axes coordinate systems. This allows the system to adapt to positional deviations by calculating and applying coordinate transformations, thereby maintaining accurate position recognition despite mechanical variations.
2Ease of operation
If ball screws are used for moving mechanism to horizontally move imaging unit, then movement is achieved, but local position error occurs between command position and moved position
Solution Approach 1:
The patent implements a feedback mechanism where the actual position of the imaging unit is detected through imaging recognition marks on the substrate and mask plate. This actual position information is fed back to the control system, which then corrects positioning errors by adjusting subsequent movement commands, thereby compensating for ball screw positioning inaccuracies.
Solution Approach 2:
The patent substitutes mechanical positioning precision requirements with an optical detection and computational correction system. By using imaging units to detect mark positions and performing coordinate transformations, the system achieves high positioning precision without relying solely on mechanical accuracy.
3Manufacturing precision
If calibration processing is conducted to confirm positioning precision, then positioning accuracy can be verified, but complicated operation and processing are required making it difficult to confirm during production
Solution Approach 1:
The patent enables the imaging unit to perform self-calibration by imaging recognition marks on the substrate and mask plate and automatically calculating coordinate transformations. This self-service calibration process eliminates the need for complex external calibration procedures and allows positioning precision to be confirmed quickly during production without interrupting the workflow.
Data Source
AI summary
Prior to a mark imaging process executed for the purpose of detecting a position of recognition marks for positioning the substrate and the mask, an optical axis calibration processing process of detecting a horizontal relative position between imaging optical axes, and a surface correction data creation processing process of detecting a local positional deviation of the imaging optical axes, which is caused by the travel of the imaging unit, are executed. Before starting production, a production pre-start precision evaluation process for evaluating a substrate positioning precision is executed by using a verification substrate and a verification mask, and after starting the production, a production post-start precision evaluation process for evaluating a substrate positioning precision after starting the production is executed by using a commercial production substrate and a commercial production mask.