Ink-jet Printing Substrate Alignment via Dual Compensation Periods
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Solution Overview
Problem
Existing ink-jet printing technologies face challenges in accurately aligning substrates for display device manufacturing, particularly due to errors in measuring and adjusting alignment marks during the printing process.
Innovation Solution
The proposed ink-jet printing apparatus includes a stage with a substrate mounted, an ink-jet head, a mark measuring part for aligning alignment marks, and a substrate fixing part that moves the substrate to align the marks accurately. This apparatus measures the coordinates of alignment marks during compensation periods and adjusts the substrate's position based on these measurements to ensure precise alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If substrate alignment is performed using conventional single-period measurement methods, then the alignment process is simple and fast, but measurement precision and manufacturing precision deteriorate due to errors in measuring and adjusting alignment marks
Solution Approach 1:
The patent performs preliminary alignment mark measurements during a first compensation period before the actual printing process, and conducts additional measurements during a second compensation period. This preliminary action allows the system to pre-determine substrate position deviations and calculate correction values in advance, improving measurement precision without compromising the printing speed significantly.
Solution Approach 2:
The patent implements a feedback mechanism where alignment mark coordinates are measured, compared against reference values, and used to generate substrate position correction instructions. The mark measuring part continuously monitors alignment mark positions, and the substrate fixing part adjusts substrate positioning based on this feedback, creating a closed-loop control system that improves alignment precision.
2Manufacturing precision
If substrate position is adjusted frequently based on real-time measurements, then manufacturing precision improves, but productivity decreases due to additional adjustment time
Solution Approach 1:
The system performs substrate alignment measurements and position corrections during compensation periods that occur before or between printing operations. By completing alignment adjustments in advance, the actual printing process can proceed without interruption, maintaining high productivity while achieving precise substrate positioning.
Solution Approach 2:
The patent divides the alignment process into periodic compensation periods (first and second compensation periods) rather than continuous adjustments during printing. This periodic measurement and correction approach allows the system to maintain manufacturing precision while minimizing interference with the continuous printing workflow, thereby preserving productivity.
3Manufacturing precision
If alignment marks are measured and substrate is repositioned multiple times, then manufacturing precision improves, but loss of time increases due to multiple compensation periods
Solution Approach 1:
The system performs the majority of alignment measurements and corrections during a first compensation period before the second compensation period. This preliminary correction approach addresses most positioning errors in one go, reducing the need for extensive adjustments later and minimizing total time loss.
Solution Approach 2:
The patent introduces a coordinate comparison mechanism as an intermediary step that efficiently translates alignment mark measurements into substrate position corrections. By using reference coordinates and calculating position deviations mathematically, the system achieves precise alignment without requiring multiple physical measurement cycles, thereby reducing time loss.
Data Source
AI summary
An ink-jet printing apparatus includes: a stage on which a substrate including first and second alignment marks is mounted; an ink-jet head part discharging ink; a mark measuring part measuring a first coordinate of each of the first and second alignment marks during a first compensation period, the mark measuring part measuring a second coordinate of the first alignment mark during a second compensation period; and a substrate fixing part holding the substrate. The substrate fixing part performs a first operation to move the substrate such that the first coordinates of the first and second alignment marks in a first direction align with each other during the first compensation period, and performs a second operation to move the substrate according to a result obtained by comparing the second coordinate of the first alignment mark with a reference coordinate of the first alignment mark during the second compensation period.