Inkjet Nozzle Velocity Evaluation for Accurate Display Droplet Placement
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Solution Overview
Problem
The jetting characteristic of inkjet printer heads, which affects printing quality in display devices, is not accurately evaluated, leading to potential defects in the formation of droplets on substrates.
Innovation Solution
A method and device that calculate jetting velocity by adjusting nozzle separation distances and observing hit changes, using image analysis to detect defective nozzles before and during the manufacturing process, ensuring accurate droplet placement and improved display quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If jetting characteristic is evaluated using conventional methods, then evaluation can be performed, but measurement precision is insufficient leading to inaccurate jetting velocity measurement
Solution Approach 1:
The patent applies preliminary action by evaluating jetting characteristics before the actual printing process. Multiple droplets are formed at different separation distances in advance, and their positions are measured to calculate jetting velocity. This preliminary evaluation ensures that only nozzles with appropriate jetting characteristics are used for subsequent manufacturing, preventing defects before they occur.
Solution Approach 2:
The patent implements feedback by measuring the actual positions of formed droplets and comparing them against expected positions. The jetting velocity is calculated based on the difference between actual and expected droplet positions, and this information is fed back to determine whether the nozzle meets the required specifications. This feedback mechanism ensures reliable droplet placement by identifying and excluding defective nozzles.
2Measurement precision
If multiple droplets are formed at different separation distances to measure jetting velocity, then measurement precision improves, but device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the evaluation process into distinct steps: forming droplets at multiple specific separation distances, measuring their positions, calculating jetting velocity, and determining nozzle suitability. This segmentation allows the complex measurement task to be broken down into manageable operations, each performed systematically to achieve accurate results without overwhelming complexity.
Solution Approach 2:
The patent uses dimensionality change by measuring droplet positions in multiple dimensions (different separation distances and corresponding positional deviations). By forming droplets at multiple separation distances and measuring their positions in these dimensional variations, the system calculates jetting velocity more accurately. This multi-dimensional approach transforms a single-point measurement into a comprehensive evaluation while maintaining systematic process control.
3Reliability
If jetting velocity is not accurately measured, then manufacturing process is simpler, but defective nozzles are not identified leading to quality issues
Solution Approach 1:
The patent applies preliminary action by performing nozzle evaluation before the main manufacturing process. Multiple droplets are formed and measured in advance to calculate jetting velocity, and nozzles are screened for defects beforehand. This preliminary screening identifies defective nozzles before they are used in production, ensuring high display device quality while minimizing interruptions during manufacturing.
Solution Approach 2:
The patent implements feedback by continuously measuring droplet positions, calculating jetting velocities, and comparing results against acceptable ranges. This feedback loop identifies defective nozzles in real-time during evaluation, allowing for immediate exclusion from production. The feedback mechanism ensures quality through systematic monitoring while maintaining manufacturing efficiency by preventing defective nozzles from compromising production.
Data Source
AI summary
A manufacturing method of a display device includes forming a first droplet on a first region of a substrate by nozzles, moving the nozzles onto a second region of the substrate spaced apart in a first direction from the first region, forming a second droplet on the second region, calculating a first distance between the first and second droplets, moving the nozzles onto a third region of the substrate spaced apart in a direction opposite to the first direction from the second region, forming a third droplet on the third region, moving the nozzles onto a fourth region of the substrate spaced apart in the first direction from the third region, forming a fourth droplet on the fourth region, calculating a second distance between the third and the fourth droplets, and calculating a jetting velocity of each of the nozzles based on the first distance and the second distance.