Inkjet Display Panel Coating With Randomized Subpixel Areas
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Solution Overview
Problem
Inkjet-based display panel manufacturing faces challenges with color unevenness due to inconsistent ink droplet volumes from nozzles, leading to material waste and complexity in drive circuits, especially for expensive and chemically vulnerable materials like OLEDs and quantum dots.
Innovation Solution
Forming black matrices with randomly varying subpixel areas and using a single inkjet print head to apply the same amount of RGB ink, which is then dried or cured, simplifying the drive circuit and minimizing the number of ink droplet applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If photolithography process is used to configure subpixels, then manufacturing precision is improved, but material waste increases significantly
Solution Approach 1:
The patent extracts and removes the photolithography process from the manufacturing flow, replacing it with inkjet printing. This eliminates the need for complex photoresist application, exposure, and development steps that cause significant material waste, while still achieving precise subpixel configuration through digital inkjet deposition.
Solution Approach 2:
The patent replaces the mechanical photolithography system with an inkjet printing system. Instead of using photoresist, UV exposure, and chemical development, the invention uses non-contact inkjet deposition to directly apply color materials, eliminating material waste associated with the photolithography process.
2Loss of substance
If inkjet printing is used to apply color resist, then material waste is reduced, but color unevenness occurs due to inconsistent ink droplet volumes
Solution Approach 1:
The patent converts the harmful effect of inconsistent ink droplet volumes into a beneficial randomization mechanism. Instead of trying to eliminate thickness variations, the invention intentionally allows random thickness differences that mask color unevenness, transforming a manufacturing defect into a visual quality improvement.
3Manufacturing precision
If multiple inkjet patterns are applied per display panel, then color uniformity is improved, but productivity decreases and drive circuit complexity increases
Solution Approach 1:
The patent merges multiple inkjet printing operations into a single pass by applying all necessary color resists (red, green, blue) simultaneously to their respective subpixels. This consolidation eliminates the need for multiple sequential printing patterns, thereby improving productivity while maintaining color uniformity through the random thickness variation effect.
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 ensures visually imperceptible color deviation between subpixels, enhancing productivity by reducing the complexity of the drive circuit and minimizing ink droplet applications, while being suitable for various display technologies like OLED, QD, and LED panels.
Implementation Method 1
ejecting RGB ink to lay down the same amount of an RGB ink to the subpixels from a plurality of inkjet print head nozzles
Implementation Method 2
drying the RGB ink sprayed on the subpixels with a dryer
Implementation Method 3
curing with an ultraviolet curing device
Data Source
AI summary
Proposed is a method for manufacturing display panel with no color unevenness using an inkjet and, more particularly, to a method for manufacturing display panel with no color unevenness using an inkjet. The method may include applying the same amount of ink droplets to respective subpixels having randomly different areas so that the thickness of a coating film is randomly varied. A color deviation of the subpixels can be randomized so that the human eye may not perceive color unevenness.