Viscous Media Ejector Control for Consistent Droplet Deposition
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Solution Overview
Problem
Existing ejector systems for jetting viscous media onto substrates face challenges in achieving high production accuracy and reliability, often resulting in issues such as dry joints, short-circuiting, and defective contacts due to variations in droplet size and shape.
Innovation Solution
A method for controlling an ejector that involves obtaining a control parameter based on factors such as the time period between droplets, differences in target size and actual size of previous droplets, and the droplet's position in the sequence, to optimize the actuating force and feeding rate for precise droplet ejection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the actuator arrangement operates with fixed parameters to eject droplets, then the device complexity is reduced, but the manufacturing precision of deposits deteriorates due to variations in droplet size and shape
Solution Approach 1:
The control parameter is made dynamic by adjusting it based on the position of the droplet in the sequence. This allows the actuator arrangement to adapt its operation (e.g., actuation voltage, pulse width) to compensate for rheological effects that vary with sequential position, thereby improving deposit precision without requiring complex real-time sensing systems
Solution Approach 2:
The system implements feedback by using the droplet sequence position information to adjust the control parameter for subsequent droplets. This feedback mechanism compensates for cumulative rheological effects and ensures consistent droplet characteristics, improving manufacturing precision through intelligent parameter adjustment
2Productivity
If the feeding rate is increased to maintain production speed, then the productivity is improved, but the manufacturing precision deteriorates due to variations in droplet volume
Solution Approach 1:
The feeding rate is made dynamic rather than fixed. The system adjusts the feeding rate based on the droplet sequence position to compensate for rheological effects, ensuring consistent droplet volumes even at high production speeds. This dynamic adjustment reconciles the conflict between productivity and precision
3Reliability
If the actuator arrangement uses high actuating force to ensure droplet ejection, then the reliability of droplet formation is improved, but the manufacturing precision deteriorates due to droplet deformation and spraying
Solution Approach 1:
The actuating force is made dynamic by adjusting the control parameter based on droplet sequence position. This allows the system to apply optimal force levels that ensure reliable droplet formation without excessive force that would cause deformation or spraying, thereby maintaining both reliability and precision
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables improved control over the size and quality of deposits on the substrate, enhancing the reliability and accuracy of the jetting process by accounting for the rheological characteristics of the viscous medium and adjusting parameters accordingly.
Implementation Method 1
jetting droplets of viscous medium or fluid
Implementation Method 2
facilitate droplet formation
Data Source
AI summary
A method for controlling an ejector is disclosed, wherein the ejector comprises an actuator arrangement configured to eject a droplet of viscous medium onto a substrate, and wherein the droplet forms part of a sequence of a plurality of droplets. The method comprises obtaining a control parameter for controlling the operation of the actuator arrangement, and operating the actuator arrangement, using the control parameter, in order to eject the droplet. The obtained control parameter is based on at least one of: a time period between the droplet and a previous droplet in the sequence, a difference in target size of the droplet and a size of the previous droplet in the sequence, and the droplets position in the sequence.