Inkjet Drive Waveform Correction for Film Thickness Uniformity
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Solution Overview
Problem
Inkjet methods for manufacturing color filters in liquid crystal displays face issues with non-uniform droplet weights, leading to variations in film thickness, which deteriorate display quality due to differences in droplet weights from nozzles in a row.
Innovation Solution
A droplet ejection head drive method that associates nozzles with ranks based on droplet weights, generates drive waveforms to standardize droplet weights, and supplies these waveforms to selected nozzles to ensure uniform droplet ejection, thereby correcting droplet weights and improving film thickness uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If common drive waveform signals are inputted to actuators, then the device complexity is reduced and ease of operation is improved, but manufacturing precision deteriorates due to non-uniform droplet weights from different nozzles
Solution Approach 1:
The patent applies local quality by assigning different drive waveform signals to different nozzles based on their individual droplet weight characteristics. Each nozzle is classified into a rank group according to its droplet weight, and specific drive waveforms are tailored for each rank to correct weight deviations. This localized adjustment ensures that each nozzle operates optimally for its specific characteristics, thereby achieving uniform film thickness across all nozzles while maintaining manageable system complexity through systematic classification.
2Manufacturing precision
If drive waveforms are corrected for each nozzle rank, then manufacturing precision of film thickness is improved, but device complexity increases due to multiple waveform management
Solution Approach 1:
The patent applies segmentation by dividing nozzles into discrete rank groups based on their droplet weight measurements. Instead of individually adjusting each nozzle, the system segments nozzles into categories (rank 1, rank 2, etc.) where each rank receives a specific standardized drive waveform. This segmentation approach simplifies waveform management by reducing the number of unique waveforms needed while still achieving precise droplet weight control across all nozzles through the ranked classification system.
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 standardizes droplet weights for each nozzle, enhancing the uniformity of film thickness and improving the optical characteristics of the liquid crystal display by ensuring consistent droplet ejection patterns.
Implementation Method 1
multiple actuators (for example, piezoelectric elements, resistance heating elements, etc.) for pressurizing the liquid in the cavities
Implementation Method 2
multiple actuators (for example, piezoelectric elements, resistance heating elements, etc.) for pressurizing the liquid in the cavities
Data Source
AI summary
A droplet ejection head drive method includes (1) associating multiple nozzles with ranks corresponding to weights of droplets ejected from the nozzles, (2) generating drive waveforms for driving actuators of the nozzles and correcting the weights of the droplets to a predetermined weight, for each of the ranks, and (3) supplying the drive waveforms corresponding to the ranks of some of the nozzles selected according to drawing data, to actuators of the selected nozzles and ejecting droplets each having the predetermined weight from the selected nozzles onto a target.