Groove Pattern Containment for LCD Orientation Film Inkjet Printing
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Solution Overview
Problem
The inkjet printing method for forming orientation films in liquid crystal display devices faces challenges in controlling the position of the outer perimeter of the applied region due to low viscosity ink, leading to spreading and potential defects such as insufficient adhesiveness and liquid crystal material leakage.
Innovation Solution
The implementation of a liquid crystal display device structure featuring an annular sealing material with conductive layers and insulation layers, including recessed grooves on the substrate to prevent spreading of the orientation film material ink, ensuring it does not reach the sealing region and maintaining uniform film thickness within the display area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the inkjet printing method is used to form the orientation film, then the contamination of substrate surfaces and fabrication facility is reduced and solvent consumption is decreased, but the position of the outer periphery of the applied region cannot be controlled due to low viscosity ink spreading
Solution Approach 1:
A guide pattern layer is introduced as an intermediary between the inkjet printing process and the final orientation film. This guide pattern layer has a groove pattern that acts as a physical barrier to contain the low-viscosity orientation film material ink within the display region, preventing it from spreading to the sealing region while still allowing the inkjet method's contamination reduction benefits to be realized.
2Loss of time
If the orientation film material ink is applied using inkjet printing, then the process time is shortened, but the ink spreads by wetting and reaches the sealing region causing insufficient adhesiveness
Solution Approach 1:
The guide pattern layer with groove patterns is formed in advance before the inkjet printing of the orientation film material. These pre-formed grooves create physical boundaries that prevent the ink from spreading to the sealing region, ensuring proper adhesiveness is maintained while allowing the quick inkjet printing process to proceed without additional containment steps.
3Manufacturing precision
If the viscosity of the orientation material ink is increased to suppress spreading, then the spreading by wetting is reduced, but injection failure occurs due to clogging of the nozzle
Solution Approach 1:
Instead of changing the viscosity of the entire orientation film material ink, the guide pattern layer introduces localized structural variations through groove patterns. These grooves are strategically positioned to provide containment exactly where needed at the boundaries between the display region and sealing region, while the bulk ink maintains its low viscosity for reliable inkjet injection.
4Loss of substance
If the inkjet printing method is used, then solvent consumption is reduced, but the outer periphery of the applied region spreads uncontrollably
Solution Approach 1:
The guide pattern layer serves as a mediator that enables the use of low-solvent inkjet printing while preventing uncontrolled spreading. The groove patterns in the guide layer create physical boundaries that contain the orientation film material within the display region, allowing the process to benefit from reduced solvent consumption without sacrificing positional control.
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 solution effectively suppresses unwanted spreading of the orientation film material, ensuring proper adhesiveness and preventing defects like positional displacement and leakage, while maintaining uniformity of the film thickness within the display region.
Implementation Method 1
a groove portion which has a recessed groove opening on the orientation film side
Implementation Method 2
it is difficult to control the position of the outer periphery of the applied region formed along with spreading by wetting of the orientation material ink
Data Source
AI summary
An LCD device has a pair of substrates including orientation films on surfaces thereof which face opposing substrates. The substrate on which signal lines are formed, on a side thereof which is disposed between a region on which sealing material is arranged and a display region and along which the signal lines extend to the outside of the sealing material from the display region, includes a first conductive layer, a second conductive layer and an insulation layer which is interposed therebetween. The insulation layer extends in the direction at least along an outer periphery of the display region, and includes groove portion having a recessed groove which opens on the orientation film side. The first conductive layer is covered on the surface of the recessed groove. The signal lines are formed in a state that the signal lines go around the recessed groove.