Inkjet Head Microdroplet Ejection via Ink Column Segmentation
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Solution Overview
Problem
Current inkjet technologies face challenges in ejecting microdroplets smaller than the nozzle diameter, leading to grainy images and clogging issues, and are unable to meet the requirements of high-density interconnects and ultrathin films due to limitations in nozzle accuracy and clogging.
Innovation Solution
A method involving an inkjet head with a plate and pressure generating member, where a meniscus is controlled to form ink columns and microdroplets by varying the driving voltage, allowing for the separation and merging of ink columns to eject microdroplets smaller than the nozzle diameter, achieving sub-picoliter volumes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the nozzle diameter is reduced to eject smaller ink droplets, then the droplet size decreases, but the production cost increases and clogging occurs more easily
Solution Approach 1:
The ink ejection process is segmented into multiple phases: first forming an ink column, then separating the tip end to create a microdroplet, and finally using a second ink column to push the microdroplet out. This segmentation allows the use of larger nozzle diameters while still achieving sub-picoliter droplet volumes through controlled separation and ejection mechanics.
Solution Approach 2:
The method performs preliminary actions by first forming an ink column and separating its tip end to create a microdroplet before actual ejection. This preliminary formation and separation process enables the subsequent ejection of precisely sized microdroplets without requiring small nozzle diameters, thereby preventing clogging while maintaining reliability.
2Manufacturing precision
If the nozzle diameter is reduced to achieve higher precision, then the manufacturing accuracy improves, but the production cost increases
Solution Approach 1:
The invention changes the parameters of the ink ejection process by using larger nozzle diameters combined with controlled ink column formation and separation. Instead of relying on small nozzle dimensions for precision, the method achieves sub-picoliter droplet precision through controlled volume changes and separation mechanics, thereby reducing manufacturing costs while maintaining high precision.
3Manufacturing precision
If the ink droplet volume is reduced to eliminate graininess, then the image quality improves, but the ejection velocity requirements increase
Solution Approach 1:
The method employs periodic action by first forming an ink column, then separating and ejecting a microdroplet, followed by returning the remaining ink column to the pressure chamber. This periodic cycle of formation, separation, ejection, and return enables consistent sub-picoliter droplet delivery with controlled velocities, improving image quality while managing ejection speed requirements.
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
Enables the stable ejection of microdroplets at high velocities, overcoming the limitations of grainy images and clogging, and facilitating the formation of high-density interconnects and uniform ultrathin films by precisely controlling ink volume and velocity.
Implementation Method 1
The pressure generating member applies pressure to ink in each ink pressure chamber in response to electric signals applied to the pressure generating member
Implementation Method 2
one method enables the ejection of ink droplets that are smaller than the nozzle diameter by controlling oscillations of the ink surface in the nozzle opening (hereinafter referred to as the 'meniscus')
Data Source
AI summary
The method of ejecting microdroplets of ink includes a first step for generating one ink column on the outside of the nozzle and for separating a tip end of the one ink column from a remaining part of the one ink column to form a microdroplet of ink on the outside of one nozzle, and a second step for controlling an ink volume velocity in the ink pressure chamber that is connected to the nozzle to generate another ink column and to push the another ink column out of the nozzle, thereby causing the another ink column to overtake and merge with the remaining part of the one ink column and to return into the nozzle while pulling the remaining part of the one ink column back into the nozzle.