Inkjet Printing Alignment Layer Uniformity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing LCD alignment layer printing technologies, such as flexography and inkjet methods, suffer from ink wastage and undesirable thickness variations leading to longitudinal 'stripes' in the alignment layer, which affect the alignment of liquid crystal molecules and image quality.
Innovation Solution
An inkjet printing apparatus with a novel orifice unit and control system, featuring piezoelectric elements and variable resistors, which allows for precise control of ink ejection and spacing between nozzles, enabling uniform thickness application of the alignment layer in a single pass without stripe formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If flexography technique is used to print alignment layer, then alignment layer can be formed on substrate, but large amount of ink is wasted
Solution Approach 1:
The patent replaces the mechanical flexography system with a piezoelectric inkjet system. The piezoelectric elements precisely control ink ejection at the molecular level, eliminating the need for mechanical rollers and resin plates that cause ink wastage. This substitution achieves both precise alignment layer formation and significant ink savings.
Solution Approach 2:
The patent changes the fundamental parameter of ink delivery from mechanical contact-based (flexography) to electro-based (piezoelectric). By controlling the voltage applied to piezoelectric elements, the system precisely regulates ink ejection volume and positioning, eliminating the ink wastage inherent in mechanical systems while maintaining alignment layer formation capability.
2Manufacturing precision
If ink jet head with spaced nozzles is used, then direct ink ejection is achieved, but thickness variation and stripe formation occur
Solution Approach 1:
The patent segments the ink ejection function by assigning multiple nozzles to each piezoelectric element, with each nozzle serving a specific sub-region. This segmentation allows independent control of ink ejection in different areas, enabling uniform thickness distribution across the entire alignment layer while maintaining the simplicity of the overall device structure.
Solution Approach 2:
The patent incorporates feedback control through variable resistors that adjust the voltage applied to piezoelectric elements based on real-time monitoring of ink ejection patterns. This feedback mechanism dynamically compensates for any thickness variations or stripe formations, ensuring uniform alignment layer thickness without requiring complex mechanical adjustments.
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 apparatus ensures a uniform alignment layer thickness, reducing ink wastage and eliminating longitudinal stripes, thereby enhancing the quality of the liquid crystal display by improving the alignment of molecules and image formation.
Implementation Method 1
an ink jet head incorporating a structure for ensuring that the printed alignment layer has a uniform thickness
Data Source
AI summary
An apparatus for printing a liquid crystal alignment layer of uniform thickness on a substrate of an LCD and a method for its use include an ink jet head that prevents the formation of stripes in the alignment layer as a result of variations in thickness of the alignment layer. The apparatus includes an alignment layer ink ejecting unit that includes an orifice unit having a plurality of orifices, and a plurality of control units, each including a piezoelectric element that controls the flow of ink through a corresponding one of the orifices. Each of the orifices includes a plurality of ink ejection passages through which the ink is ejected, and each of the passages terminates at nozzle, or ink ejection hole.