Inkjet Nozzle Misalignment Compensation via Dummy Ink Calibration
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Solution Overview
Problem
Inkjet printing for color filters in liquid crystal displays faces challenges in maintaining symmetrical ink distribution, leading to misalignment and spread of ink between neighboring filters, which deteriorates display characteristics.
Innovation Solution
A method involving the use of a dummy ink drop and CCD imaging to calculate and adjust the ink drip time for each nozzle, ensuring precise positioning by compensating for misalignment, using a reference point determined by the inkjet printer's coordinate system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If ink is dripped using an inkjet printer with multiple nozzles, then color filter ink can be deposited efficiently, but misalignment of ink droplets occurs leading to spread between neighboring filters
Solution Approach 1:
The patent applies preliminary action by dripping dummy ink drops before the actual color filter ink to detect and measure nozzle misalignment. The dummy ink drops serve as reference markers that allow the system to calculate escape values and determine time adjustment values for each nozzle before actual production, thereby preventing positioning errors in the final ink deposition.
Solution Approach 2:
The patent implements feedback by using a CCD camera to capture images of the dummy ink drops, calculating their actual positions, and comparing them with reference positions. This feedback loop generates escape values that quantify the misalignment, which then feeds into the time adjustment calculation to compensate for nozzle positioning errors in subsequent ink deposition.
2Manufacturing precision
If engineer directly checks and controls dripping position, then ink can be dripped at correct positions, but it is difficult to determine numerical nozzle movement when ink shape is asymmetrical
Solution Approach 1:
The patent introduces an intermediary measurement system consisting of dummy ink drops and CCD imaging. Instead of directly measuring nozzle positions or relying on visual inspection of asymmetrical ink shapes, the system uses the symmetrical dummy ink drops as intermediaries to indirectly measure and quantify nozzle misalignment through image analysis and escape value calculation.
Solution Approach 2:
The patent transforms the physical misalignment parameter into a measurable escape value parameter. By capturing CCD images of dummy ink drops and calculating the deviation between actual and reference positions, the system converts physical nozzle displacement into quantifiable escape values that can be used to determine time adjustment parameters for correction.
3Ease of manufacture
If ink is dripped without position compensation, then manufacturing process is simple, but ink spreads between neighboring color filters deteriorating display characteristics
Solution Approach 1:
The patent applies preliminary action by performing a calibration step with dummy ink drops before actual color filter ink deposition. This preliminary measurement and calculation of time adjustment values adds a step to the manufacturing process, but ensures that subsequent ink deposition achieves proper positioning and prevents ink spread that would compromise display quality.
Solution Approach 2:
The patent implements feedback by measuring actual nozzle positions using dummy ink drops and CCD imaging, then using this information to calculate compensatory time adjustments. This feedback mechanism ensures that display characteristics quality is maintained by preventing ink spread between neighboring filters, justifying the additional measurement and calculation steps required.
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
This method effectively compensates for misalignment, ensuring ink is dripped at the correct position, reducing spread between neighboring filters, improving display characteristics and reducing manufacturing costs and time.
Implementation Method 1
providing a CCD (charge-coupled device) image of the dripped dummy ink drop
Data Source
AI summary
A method for inkjet printing includes providing a light blocking member pattern including a plurality of openings at positions corresponding to pixels, dripping a dummy ink drop on the light blocking member pattern by using an inkjet printer, providing a CCD (charge-coupled device) image for the dripped dummy ink drop, representing the CCD image on rectangular coordinates, calculating a central point under an x-axis and a y-axis of the CCD image, calculating an escape value as a deviation of the central point under the x-axis and the y-axis in the CCD image from a reference point established by the inkjet printer, calculating a time adjustment value of the ink drip based on the escape value, and controlling the time for the ink drip for each nozzle of the inkjet printer by the time adjustment value of the ink drip.