Ink Jetting Apparatus Guide Channel Evaporation Control
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Solution Overview
Problem
Conventional ink jetting apparatuses using piezoelectric and electrohydrodynamic methods face limitations in achieving fine line widths due to instability in droplet evaporation and accumulation of electric charges, leading to difficulties in printing precise patterns on large substrates with non-uniform flatness and nozzle clogging issues.
Innovation Solution
An ink jetting apparatus with a guide channel unit that controls evaporation and electric charge management, combined with a nozzle unit and gas supply system, to generate and discharge micro-fine liquid droplets, preventing spray formation and allowing precise printing on large substrates without the need for micro-fine nozzles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the distance between the nozzle and the substrate is increased to enable printing on large substrates, then the adaptability to large substrates is improved, but the manufacturing precision of fine line widths deteriorates due to insufficient electric field intensity
Solution Approach 1:
The patent changes the fundamental parameter of droplet generation from electrohydrodynamic (continuous jetting via electric field) to piezoelectric (drop-on-demand via pressure control). This parameter change allows the system to operate at larger nozzle-to-substrate distances while maintaining precise line width control, as the piezoelectric method generates discrete droplets whose size is controlled by pressure rather than electric field intensity.
Solution Approach 2:
The patent replaces the electrohydrodynamic system (which relies on strong electric fields and continuous jetting) with a piezoelectric drop-on-demand system. This substitution eliminates the need for high-voltage electric fields, allowing stable operation at larger distances from the substrate while maintaining fine line width precision through controlled droplet ejection.
2Manufacturing precision
If the nozzle diameter is reduced to several micrometers to achieve fine line widths, then the manufacturing precision is improved, but the reliability deteriorates due to nozzle clogging from nano-particles in functional ink
Solution Approach 1:
The patent applies preliminary action by controlling the evaporation of liquid droplets in a guide channel unit before the droplets reach the nozzle. This pre-evaporation reduces the liquid content and concentrates the solid components, allowing the use of larger nozzle diameters that are less susceptible to clogging from nano-particles in functional ink, while still achieving fine line width precision through controlled droplet size and evaporation.
3Force
If the electric charges on liquid droplets are increased to enhance the electrohydrodynamic jetting effect, then the jetting force is improved, but the stability deteriorates when electric charges exceed the Rayleigh limit causing droplet pulverization
Solution Approach 1:
The patent replaces the electrohydrodynamic jetting mechanism (which relies on electric charges and electric field forces) with a piezoelectric drop-on-demand mechanism. This substitution eliminates the issue of electric charge accumulation and Rayleigh limit exceeded problems, as the piezoelectric method controls droplet ejection through mechanical pressure from piezoelectric elements rather than electric charges, ensuring stable droplet formation without pulverization.
4Manufacturing precision
If the liquid droplet volume is reduced to picoliter or femtoliter size to achieve fine line widths, then the manufacturing precision is improved, but the productivity deteriorates due to the time-consuming nature of generating and patterning such small droplets
Solution Approach 1:
The patent changes the droplet generation parameter from picoliter/femtoliter scale (electrohydrodynamic) to larger droplet sizes with controlled evaporation (piezoelectric drop-on-demand). By using larger initial droplet volumes that undergo controlled evaporation in the guide channel, the system achieves fine line width precision while maintaining higher productivity, as larger droplets can be generated and ejected more quickly than ultra-fine droplets.
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 formation of micro-fine line widths of less than 1 micrometer, stable printing on large substrates, and increased solid content patterns, while preventing nozzle clogging and maintaining droplet stability.
Implementation Method 1
capable of controlling and using evaporation of the liquid droplets in the process where the liquid droplets pass through the guide channel unit
Implementation Method 2
The piezoelectric method ink jetting apparatuses use a method where pressurization by a piezoelectric element pushes and discharges the ink accommodated in a chamber
Implementation Method 3
in the electrohydrodynamic (EHD) method, ink is discharged by the electrostatic force caused by a potential difference generated between electrodes
Implementation Method 4
since, in the case of the electrohydrodynamic (EHD) method, jetting is performed in the principle of using electric force to pull a meniscus from a nozzle, excessive electric charges will be accumulated on liquid droplets
Data Source
AI summary
The present disclosure relates to an ink jetting apparatus and a printing system including the same, the ink jetting apparatus including a liquid droplet generating unit configured to generate liquid droplets and jet the generated liquid droplets, a guide channel unit having a channel to guide the jetted liquid droplets and control evaporation of the liquid droplets, and being configured to protect the liquid droplets from thermal and physical disturbance; and a nozzle unit configured to discharge the liquid droplets that passed through the guide channel unit towards a substrate.