LCD Alignment Layer Pinhole Repair via Localized Solution
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Solution Overview
Problem
Liquid crystal displays (LCDs) in the vertically aligned mode face issues with side visibility degradation and pinhole formation during the manufacturing process of the alignment layer, leading to bad pixels and reduced display quality.
Innovation Solution
An LCD with a substrate and an alignment layer containing a vertical functional group and a photoreactive group, along with a repair layer filled in the pinhole, where the repair layer and alignment unit share similar solvent and polymer compositions to maintain uniformity and prevent pinhole-induced bad pixels, using a repair solution with specific weight percentages of N-methyl pyrrolidone, butyl carbitol, polycarbonate, and additives, and employing a method to detect and remove foreign particles using laser beams and inkjet printing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an alignment layer is formed during the manufacturing process, then the liquid crystal molecules can be properly aligned, but pinholes may form in the alignment layer leading to bad pixels
Solution Approach 1:
The patent applies preliminary action by forming a repair layer on the alignment layer before the alignment layer is fully cured. The repair layer is applied in advance to prevent pinhole formation, and then the alignment layer is cured to complete the repair process. This proactive approach addresses pinholes before they can cause bad pixels, thereby improving display quality while managing the harmful effect of pinhole formation during manufacturing.
2Reliability
If a repair layer is applied to fix pinholes, then bad pixels can be prevented, but the manufacturing process becomes more complex
Solution Approach 1:
The patent applies local quality by forming a repair layer only in specific regions where pinholes are detected, rather than treating the entire alignment layer uniformly. The repair layer is applied locally to affected areas, and then cured to restore pixel functionality. This targeted approach prevents bad pixels while minimizing the increase in manufacturing process complexity compared to a full-layer repair approach.
3Reliability
If the alignment layer configuration is made uniform to prevent bad pixels, then display quality improves, but the manufacturing precision requirements increase
Solution Approach 1:
The patent applies preliminary action by forming a repair layer on the alignment layer before the alignment layer is fully cured. The repair layer is applied in advance to prevent pinhole formation, and then the alignment layer is cured to complete the repair process. This proactive approach addresses pinholes before they can cause bad pixels, thereby improving display quality while managing the harmful effect of pinhole formation during manufacturing.
Solution Approach 2:
The patent applies parameter changes by controlling the curing conditions of the alignment layer and repair layer to achieve uniform configuration. By adjusting curing parameters such as temperature, time, and UV irradiation intensity, the patent ensures that the repair layer integrates uniformly with the alignment layer, maintaining consistent thickness and optical properties. This reduces the manufacturing precision requirements while achieving the desired uniformity for high display quality.
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 effectively repairs pinholes during the manufacturing process, ensuring uniform alignment layer configurations and preventing bad pixels, thereby enhancing the display quality and maintaining the same height and composition as the surrounding alignment layer, thus improving the LCD's performance.
Implementation Method 1
the alignment layer includes an alignment unit including a vertical functional group and a photoreactive group
Data Source
AI summary
A liquid crystal display includes a substrate, an alignment layer disposed on the substrate and in which a pinhole is defined in the alignment unit, the alignment layer including an alignment unit including a vertical functional group and a photoreactive group, and a repair layer filled in the pinhole, wherein the repair layer and the alignment unit include a solvent and polymers, and the solvent of the repair layer and the alignment unit includes at least two materials with the same content, and a polymer content of the repair layer is less than a polymer content of the alignment unit.