Microcavity Ink Filling for Precise, Spill-Resistant Deposition
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Solution Overview
Problem
Challenges exist in achieving uniform, precise, and rapid filling of microcavities in substrates with ink compositions during additive manufacturing, particularly for micro-LED display devices, due to issues such as spilling of low-viscosity inks and stringing of higher viscosity inks.
Innovation Solution
An additive manufacturing system with a print head and controller that dispenses ink into microcavities while moving in a horizontal path with a directional change of at least 15 degrees, adjusting parameters like wettability, viscosity, and surface tension to ensure complete filling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the nozzle is positioned close to the microcavity sidewall to improve filling precision, then manufacturing precision is improved, but the risk of spilling low-viscosity ink increases
Solution Approach 1:
The nozzle is positioned close to the microcavity sidewall before dispensing the ink composition. This preliminary positioning ensures that when the ink is dispensed, it immediately contacts the sidewall and is guided into the cavity, preventing spilling while maintaining precision. The close proximity is established in advance before the actual filling action.
2Manufacturing precision
If the nozzle moves in a horizontal path with directional changes to improve ink distribution, then manufacturing precision is improved, but the complexity of the positioning system increases
Solution Approach 1:
The nozzle is moved in a horizontal path that includes directional changes of at least 15 degrees during the dispensing process. This dynamic movement allows the ink composition to be distributed more uniformly across the microcavity by changing the angle of deposition. The controller dynamically adjusts the nozzle position and orientation to achieve optimal ink distribution while filling the cavity.
3Productivity
If the nozzle is disposed proximal to the microcavity to improve filling speed, then productivity is improved, but the risk of stringing higher viscosity ink increases
Solution Approach 1:
The nozzle is positioned close to the microcavity sidewall before dispensing the ink composition. This preliminary positioning allows the ink to be deposited directly onto the sidewall, which acts as a guide and containment structure. For higher viscosity inks, this close proximity with the sidewall guidance prevents the ink from forming strings or droplets that would otherwise hang from the nozzle, enabling faster filling speeds.
4Manufacturing precision
If the horizontal path includes directional changes to improve ink coverage, then manufacturing precision is improved, but the time required for filling increases
Solution Approach 1:
The nozzle moves continuously in a horizontal path that includes directional changes of at least 15 degrees during the dispensing process. This continuous movement with controlled directional changes ensures that the ink composition is deposited uniformly across the microcavity surface. The controller maintains continuous dispensing action while adjusting the nozzle trajectory, eliminating idle time and ensuring that the entire cavity is filled efficiently with uniform coverage.
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
The method enables uniform and precise filling of microcavities with minimal defects, optimizing production efficiency by controlling the height and coverage of the ink composition.
Implementation Method 1
The horizontal path is created based on at least one parameter selected from the group consisting of a wettability of the substrate, a viscosity of the ink composition, a geometry of the microcavity, a surface tension of the ink composition, a contact angle between the ink composition and the substrate
Implementation Method 2
a contact angle between the ink composition and the substrate
Data Source
AI summary
An apparatus and methods for filling microcavities are provided. For example, a method can include disposing a nozzle of a print head of an additive manufacturing system proximal to a microcavity defined in a substrate. The nozzle is disposed such that a first distance between the nozzle and a sidewall of the substrate defining the microcavity is no greater than a droplet size of an ink composition. The method can further include dispensing the ink composition from the nozzle into the microcavity. The nozzle moves at least in a horizontal path while dispensing, and the horizontal path includes a directional change of at least 15 degrees.