Droplet Ejection Head Unit Seam Offset for Uniform Panel Deposition
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Solution Overview
Problem
In droplet ejection apparatuses used for manufacturing image display panels, streaks due to differences in ejection amounts or nozzle pitch errors between adjacent heads result in color heterogeneity and diminished image quality.
Innovation Solution
The head unit is designed with multiple droplet ejection heads arranged in a way that their nozzle arrays overlap consecutively, with seams shifted relative to each other, allowing for uniform ejection and preventing streaks from overlapping, thus ensuring high-quality panel manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple droplet ejection heads are arranged to cover a wider substrate area, then productivity and coverage are improved, but streaks and color heterogeneity occur due to differences in ejection amounts and nozzle pitch errors between adjacent heads
Solution Approach 1:
The patent shifts the seam positions of adjacent droplet ejection heads in the scanning direction (perpendicular to nozzle array direction), creating a dimensional offset that prevents streak overlap. This dimensional change in seam positioning resolves the contradiction by allowing multiple heads to operate simultaneously while maintaining uniform liquid material distribution across the entire substrate width.
Solution Approach 2:
The patent introduces asymmetric positioning of seams between adjacent droplet ejection heads, where seams are deliberately offset from aligning with each other in the scanning direction. This asymmetric arrangement prevents the superposition of streaks that would otherwise occur at seam locations, thereby maintaining manufacturing precision while using multiple heads for improved productivity.
2Ease of manufacture
If droplet ejection heads are positioned with aligned seams for easy manufacturing, then device complexity is reduced, but visible streaks appear due to cumulative ejection errors and nozzle pitch variations
Solution Approach 1:
The patent converts the potentially harmful aligned seam configuration into a beneficial offset seam configuration. By intentionally misaligning seams in the scanning direction, the patent transforms what would be a manufacturing complexity issue into a solution that eliminates visible streaks and color heterogeneity, improving image quality while maintaining ease of manufacture through standardized offset positioning.
Data Source
AI summary
A head unit 103 for use in a droplet ejection apparatus is provided with a plurality of droplet ejection heads for ejecting some kinds of liquid materials each having a predetermined color onto a base in the form of droplets. Each of the droplet ejection heads includes at least one nozzle array constituted from a plurality of nozzles linearly aligned. The some kinds of liquid materials are adapted to be ejected through the plurality of nozzles of the plurality of droplet ejection heads in the form of droplets. The plurality of droplet ejection heads include at least two sets of two adjacent droplet ejection heads which are arranged in a consecutive manner in a first direction parallel to each of the nozzle arrays. The two adjacent nozzle arrays of each of the at least two sets of two adjacent droplet ejection heads are arranged so that the nozzles thereof are consecutive via a seam between the two adjacent nozzle arrays of the two adjacent droplet ejection heads when viewed from a second direction perpendicular to the first direction. All the sets of two adjacent droplet ejection heads for ejecting the droplets of the some kinds of liquid materials are arranged so that all the seams thereof are shifted with respect to each other in the first direction when viewed from the second direction.