Nested Hollow Rectangular Coating for TFT-LCD Alignment Films
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Solution Overview
Problem
Conventional coating techniques for liquid crystal alignment films in TFT-LCDs, such as roller coating and inkjet coating, face issues like cumbersome equipment, poor mobility, high consumable usage, thick film difficulties, uneven film formation, and low PI usage efficiency, leading to decreased product quality and increased operating costs.
Innovation Solution
A coating method utilizing multiple sized nozzles for nested hollow rectangular coatings, where smaller nozzles are used for edge coatings and larger nozzles for central areas, allowing for continuous linear coating and reducing halo areas by employing a spreading method instead of dripping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional roller coating or inkjet coating methods are used, then the coating process can be completed, but the equipment is cumbersome, mobility is poor, and operating costs are high
Solution Approach 1:
The coating system is segmented into multiple independent nozzle groups, each capable of independent movement and coating operation. This allows the equipment to be divided into modular units that can be independently controlled and positioned, improving mobility while maintaining coating capability.
Solution Approach 2:
The nozzle array is designed to perform multiple functions: coating different regions of the substrate, adjusting coating thickness, and adapting to various substrate sizes. The same nozzle system can switch between different coating patterns and parameters, eliminating the need for multiple specialized equipment pieces.
2Loss of substance
If conventional coating methods are used, then coating can be applied, but PI usage percentage is low and consumable consumption is high
Solution Approach 1:
The conventional mechanical roller coating system is replaced with a non-contact inkjet coating system that deposits PI solution directly through nozzles. This eliminates the need for physical contact and reduces material waste from roller absorption and scraping operations, improving PI usage efficiency.
Solution Approach 2:
The coating process parameters are dynamically adjusted based on real-time feedback, including nozzle-to-substrate distance, deposition speed, and PI solution flow rate. This optimization ensures minimal PI solution is used while achieving complete and uniform coverage, reducing waste without sacrificing productivity.
3Manufacturing precision
If single nozzle coating is used, then coating process is simple, but film uniformity is poor with large uneven areas and thick edges
Solution Approach 1:
The coating system uses multiple nozzles arranged in specific patterns rather than a single nozzle. Each nozzle is responsible for a specific region of the substrate, allowing independent control of deposition in different areas. This segmentation enables precise control over film thickness and uniformity across the entire substrate surface.
Solution Approach 2:
Different nozzles or the same nozzle at different positions are used to deposit PI solution with locally optimized parameters. The system adjusts deposition characteristics for different regions of the substrate, ensuring uniform film formation while preventing edge effects and thick spots that occur with single-nozzle methods.
4Object-affected harmful factors
If conventional inkjet coating with single nozzle size is used, then equipment structure is simple, but halo areas are large and printing quality is affected
Solution Approach 1:
The system employs nozzles of different sizes positioned at different locations to address specific regional requirements. Smaller nozzles are used for edge regions where precision is critical and halo formation is problematic, while larger nozzles handle central areas where broader coverage is needed. This local optimization minimizes halo areas and improves overall printing quality.
Solution Approach 2:
The nozzle array is configured with asymmetric size distribution rather than uniform nozzle sizes. This asymmetric configuration is deliberately designed to compensate for the different coating requirements of edge versus center regions, reducing halo effects at edges while maintaining efficient coverage in the center.
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 enhances coating efficiency, reduces halo areas, and improves product quality by ensuring even film formation, thus providing a convenient and fast high-quality coating process.
Implementation Method 1
The PI drip 8 is then evenly spread on the glass substrate 1, and an even film is formed by diffusion of the PI drip 8
Implementation Method 2
an even film is formed by diffusion of the PI drip 8
Data Source
AI summary
A coating method for liquid crystal alignment film of TFT-LCD, at least two different sized nozzles are used to perform N nested hollow rectangular coatings, the N nested hollow rectangles are ordered based on 1, 2 to N measurements sequentially from the smallest to the biggest, and a smaller sized nozzle is employed for the Nth nested hollow rectangular coating on an edge.