Curved LCD Self-Alignment Layer Pretilt Angle Control
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Solution Overview
Problem
Curved liquid crystal display (LCD) devices experience misalignment during bending processing, leading to texture formation and reduced transmissivity due to differences in pretilt angles of liquid crystal molecules between the upper and lower substrate domains.
Innovation Solution
A liquid crystal display device with a self-alignment layer having a hydrophilic group at one end and a polymerized group at the other end of a core molecule, where the major axis is angled less than 90° with respect to the substrate, and an alignment layer with a vertically-aligned material, ensuring a pretilt angle difference greater than 0.5° between the two substrate surfaces, reducing misalignment and texture generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If vertically aligned mode LCD devices are used to ensure wide viewing angle and high contrast ratio, then viewing angle and contrast ratio are improved, but pretilt angle misalignment occurs during bending processing leading to texture formation
Solution Approach 1:
The patent modifies the molecular structure of the vertical alignment additive by introducing a hydrophilic group at one end of the core molecule. This parameter change in the additive's chemical structure enables differential interaction with the substrate surface, creating the desired pretilt angle distribution that prevents texture formation during bending while maintaining vertical alignment properties.
Solution Approach 2:
The patent uses a composite molecular structure for the vertical alignment additive, combining a core molecule with a hydrophilic group. This composite structure allows the additive to simultaneously provide vertical alignment functionality and control pretilt angle distribution, resolving the contradiction between maintaining alignment quality and preventing misalignment during bending.
2Adaptability or versatility
If bending processing is applied to create curved display devices, then adaptability to curved formats is improved, but misalignment between upper and lower substrate domains occurs causing texture
Solution Approach 1:
The patent applies local quality by creating different pretilt angle conditions in different regions of the liquid crystal layer. The hydrophilic group in the vertical alignment additive generates a specific pretilt angle at the substrate interface, while the bulk liquid crystal maintains vertical alignment. This spatial variation in alignment properties compensates for the differential bending of upper and lower substrates, preventing texture formation in curved displays.
Solution Approach 2:
The patent implements preliminary anti-action by pre-establishing a controlled pretilt angle distribution through the hydrophilic group-containing additive before bending occurs. This pre-configured alignment state creates a buffer that counteracts the misalignment forces generated during bending processing, maintaining alignment stability in curved configurations.
3Illumination intensity
If liquid crystal molecules are vertically aligned to achieve high contrast ratio, then contrast ratio is improved, but transmissivity reduction occurs due to misalignment in curved panels
Solution Approach 1:
The patent changes the physical-chemical parameters of the vertical alignment additive by incorporating a hydrophilic group, which modifies the interaction between the additive and liquid crystal molecules near the substrate. This parameter change enables the maintenance of optimal pretilt angles that preserve both vertical alignment for high contrast ratio and proper light transmission, preventing the transmissivity loss that would otherwise occur in curved panels.
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 reduces texture formation and maintains high transmissivity even when applied as a curved panel by aligning liquid crystal molecules to minimize luminance reduction and misalignment caused by substrate bending.
Implementation Method 1
a self-alignment layer formed between the first substrate and the liquid crystal layer, the self-alignment layer comprising a vertical alignment additive having a molecular structure having a hydrophilic group formed in an end of a core molecule, wherein the hydrophilic group faces a surface of the first substrate and a major axis of the core molecule is at an angle less than about 90° with respect to the surface of the first substrate
Implementation Method 2
liquid crystal molecules of the liquid crystal layer are aligned by using the electric field
Implementation Method 3
applying a voltage to the field-generating electrodes to generate an electric field on the liquid crystal layer, determining a direction in which the liquid crystal molecules of the liquid crystal layer are aligned by using the electric field
Implementation Method 4
controlling polarization of incident light
Data Source
AI summary
A liquid crystal display (LCD) device comprises a first substrate, a second substrate disposed to face the first substrate, a liquid crystal layer which is disposed between the first substrate and the second substrate and which includes multiple liquid crystal molecules, and a self-alignment layer formed between the first substrate and the liquid crystal layer, the self-alignment layer comprising a vertical alignment additive having a molecular structure having a hydrophilic group and a polymerized group formed in both ends of a core molecule, wherein a major axis of the vertical alignment additive is at an angle less than about 90° with respect to a surface of the first substrate.