Display Substrate Reset Zone for Uniform Rubbing
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Solution Overview
Problem
In Thin Film Transistor Liquid Crystal Displays (TFT-LCDs), the non-uniformity of alignment grooves due to uneven frictional strengths and surface deformations during the rubbing process leads to 'Rubbing Mura' and degraded display quality, particularly exacerbated by the presence of via holes for bonding ICs which disrupt the planarity of the surface.
Innovation Solution
A display substrate with a reset zone in the non-display region, where the thin film layer thickness is uniformly reduced, creating a uniform step height and size that ensures consistent deformation of the rubbing cloth, thereby maintaining alignment groove uniformity and preventing 'Rubbing Mura'. Additionally, a protective layer covers exposed areas to prevent environmental damage to lead wires.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If via holes are provided at the bonding region to connect lead wires, then electrical connection is achieved, but the planarity of the surface is degraded causing non-uniform alignment grooves
Solution Approach 1:
The patent divides the substrate into distinct regions: a first region containing via holes for bonding, and a second region without via holes. This segmentation allows the via holes to be isolated to specific areas, preventing them from affecting the planarity of the rubbing surface in the alignment region, thus resolving the contradiction between achieving electrical connection and maintaining alignment groove uniformity.
2Ease of manufacture
If thin film layers are removed at via holes, then lead wire connection is enabled, but surface planarity is degraded leading to Rubbing Mura
Solution Approach 1:
The patent applies local quality by creating a regional distinction where via holes and associated thin film removal are confined to a first region, while a second region maintains complete thin film coverage and surface planarity. This localized approach allows ease of manufacture for lead wire connection in the first region without compromising the surface quality needed for uniform alignment grooves in the second region.
3Productivity
If alignment grooves are fabricated with non-uniform depth, then rubbing process completes, but grayscale non-uniformity occurs
Solution Approach 1:
The patent performs preliminary action by pre-defining the regional structure with and without via holes before the rubbing process. This preliminary configuration ensures that when the rubbing process occurs, the surface planarity in the alignment region is already optimized, preventing non-uniform alignment groove formation and subsequent grayscale non-uniformity, thus maintaining both productivity and manufacturing precision.
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 solution ensures uniform alignment grooves, reducing grayscale non-uniformity and enhancing display quality by maintaining consistent rubbing force and protecting lead wires from environmental exposure.
Implementation Method 1
fabricate alignment grooves in a same direction at a surface of each alignment layer by a rubbing process
Implementation Method 2
different deformed zones are generated at a surface of a rubbing cloth on a rubbing roller
Data Source
AI summary
A display substrate, a manufacturing method thereof, a display panel and a display device are provided. The display substrate includes a display region and a non-display region. A reset zone is provided in the non-display region, and a thickness of a thin film layer provided in the reset zone is smaller than a thickness of a thin film layer provided in a zone adjacent to the reset zone. A step between the thin film layer in the reset zone and the thin film layer in the zone adjacent to the reset zone at the boundary of the reset zone and the zone adjacent to the reset zone is uniform in height; and in a direction within a surface of the display substrate and perpendicular to a rubbing direction of the display substrate, a size of the reset zone is greater than or equal to a size of the display region.