Liquid Coating Uniformity via Nozzle Variation Segmentation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing liquid coating methods for display devices and organic EL devices face challenges in reducing variations in coating amounts across multiple nozzles, leading to increased complexity in driving circuits and decreased productivity due to the need for precise adjustment of driving signals for each nozzle.
Innovation Solution
A method that divides the variation in coating amount into sections and assigns adjustment amounts to droplet groups, allowing for the use of a limited number of driving signals to achieve uniform coating across multiple nozzles, thereby reducing the complexity of the driving circuit and improving productivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If driving signals are adjusted for each nozzle to reduce coating amount variation, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The patent segments the continuous variation in coating amounts into discrete sections or levels. By dividing the range of coating variations into multiple sections, the system can assign specific adjustment amounts to each section, thereby reducing the complexity of the driving circuit while maintaining manufacturing precision. This segmentation allows the system to handle nozzle variations without requiring unique driving signals for every possible variation level.
Solution Approach 2:
The patent changes the parameter of driving signals by assigning different adjustment amounts based on the section to which the coating variation belongs. Instead of adjusting each nozzle individually with complex signals, the system modifies the driving signal parameters (such as voltage or pulse width) in discrete steps corresponding to different sections of coating variation. This approach simplifies the driving circuit while achieving uniform coating across nozzles with different ejection characteristics.
2Manufacturing precision
If multiple sequences of liquid ejecting head scanning are used to align nozzle positions, then manufacturing precision is improved, but productivity decreases
Solution Approach 1:
The patent performs preliminary measurement and classification of nozzle ejection amounts before the actual coating process. By obtaining nozzle information (ejection amounts) in advance and dividing nozzles into sections based on their characteristics, the system can assign appropriate adjustment amounts and driving signals beforehand. This preliminary action eliminates the need for multiple scanning sequences during production, thereby maintaining manufacturing precision while improving productivity.
Solution Approach 2:
The patent creates a model or map of nozzle characteristics (ejection amounts) in advance and uses this copied information to guide the coating process. Instead of repeatedly scanning and adjusting during production, the system uses the pre-acquired nozzle information to determine the appropriate section and adjustment amount for each nozzle, significantly reducing the number of scanning sequences required and thereby improving productivity without sacrificing precision.
3Measurement precision
If a large number of driving pulses are generated for each nozzle, then coating amount precision is improved, but device complexity increases
Solution Approach 1:
The patent applies partial adjustment by assigning adjustment amounts only to the extent necessary for each section of coating variation. Instead of using excessive driving pulses for every nozzle to achieve precise control, the system determines the appropriate adjustment level based on the nozzle's section classification. This partial action approach maintains coating amount control precision while reducing the number of driving pulses required, thereby simplifying the driving circuit.
Data Source
AI summary
Droplets of a liquid are ejected through a plurality of nozzles to a plurality of coating regions on a substrate based on nozzle information including the ejection amount of a droplet of the liquid ejected through each nozzle. According to arrangement information for disposing the liquid, a plurality of droplet groups are disposed in each coating region while the plurality of nozzles and the substrate are scanned for relative movement. A calculation is performed according to the nozzle information and the arrangement information. Adjustment amount is calculated so that the assigned adjustment amounts vary from one droplet group to another. Driving signals, which drive selected nozzles, are set so that combinations of the driving signals give coating amounts that have taken the assigned adjustment amounts into account.