Alignment Film Recess Structure for LCD Non-Display Region Narrowing
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Solution Overview
Problem
Existing liquid crystal display devices face challenges in reducing the spreading of alignment film material, which can cover terminals and disrupt circuit continuity, and in narrowing the non-display region, due to limitations in groove structures and asperity formation methods.
Innovation Solution
A recess portion with a specific bank shape on the substrate supports the edge end of the alignment film, preventing it from spreading into the picture-frame region and allowing the insulating film to protect the wiring layer, eliminating the need for a groove structure and enabling continuous formation regardless of wiring layout.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a groove structure is formed to stop alignment film material spreading, then the alignment film material can be contained, but the pixel region is spaced from the sealing material formation region making it difficult to narrow the non-display region
Solution Approach 1:
The invention transitions from a planar groove structure to a three-dimensional protrusion structure rising from the substrate surface. The alignment film material is contained not by a horizontal barrier but by a vertical obstacle, allowing the sealing material formation region to be positioned closer to the pixel region while still preventing material spread.
Solution Approach 2:
The protrusion structure acts as an intermediary element between the pixel region and sealing material formation region. It provides a physical barrier that mediates the interaction between the alignment film material and the terminals, preventing direct contact while maintaining compact device geometry.
2Reliability
If asperities are formed to control spreading by wetting, then alignment film material spreading is reduced, but asperities cannot be formed in areas where lines are present due to break risk
Solution Approach 1:
The invention applies the protrusion structure selectively in specific regions where alignment film material containment is needed, rather than uniformly across the entire substrate. This localized approach allows formation in terminal regions without interfering with wiring layer integrity in other areas.
Solution Approach 2:
The protrusion structure is segmented into discrete elements positioned at specific locations rather than forming a continuous pattern. This segmentation allows the structure to be implemented in regions suitable for protrusion formation while avoiding areas where it would compromise the wiring layer.
3Manufacturing precision
If alignment film material with low viscosity is used for ink jet printing, then the material spreads sufficiently over the substrate surface, but it reaches the terminal region and covers the terminals interrupting circuit continuity
Solution Approach 1:
The invention converts the harmful effect of low-viscosity material spread into a beneficial outcome. The same fluidity that enables sufficient coverage is allowed to occur, but the protrusion structure captures the excess material, preventing it from reaching the terminals while maintaining good coverage in the pixel region.
Solution Approach 2:
The protrusion structure serves as an intermediary barrier between the spreading alignment film material and the terminals. It intercepts the material flow, allowing the material to spread freely in the pixel region while preventing contact with the terminal region, thus preserving circuit continuity.
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 approach effectively reduces the non-display region width to about 1-2 mm, minimizes alignment film spreading, and maintains a constant liquid crystal material volume, reducing air bubbles and enhancing the reliability of the liquid crystal display device.
Implementation Method 1
spreading by wetting of the alignment film material
Data Source
AI summary
A first substrate includes a wiring layer formed on a support substrate, and an insulating film covering the wiring layer on the support substrate and having a surface which is located opposite to the support substrate and partially and directly covered with an alignment film. As seen perpendicularly to (i.e. as seen in the direction of the normal to) a surface of the support substrate, a recess portion formed on the insulating film at least partially overlaps the wiring layer. A bank of the recess portion has such a shape that a tangent plane of the bank increases in inclination toward the support substrate as the tangent plane is shifted toward a bottom of the recess portion, and supports an edge end of the alignment film.