Liquid Crystal Panel Alignment Film for Fast Response and Low Pre-Tilt
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Solution Overview
Problem
Liquid crystal panels with weak anchoring alignment films face challenges in achieving high-speed response and horizontal alignment due to pre-tilt issues, particularly in FFS and IPS modes, leading to display defects when viewed from oblique angles.
Innovation Solution
A liquid crystal panel design incorporating alignment films with specific polymer groups and liquid crystal compounds that enhance horizontal alignment and high-speed response, using a combination of compounds with polar groups and spacer structures to stabilize alignment and reduce anisotropy of dielectric properties, and a polymer having a specific polymer structure, which are polymer having a group represented by the formula (1 or 2) and a polymer having a group represented by the formula (1-A) or (2-A) to improve alignment control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If high Δn liquid crystal and narrow cell gap are used to achieve high-speed response, then response time is improved, but pre-tilt increases causing alignment defects and loss of horizontal alignment
Solution Approach 1:
The patent modifies the chemical structure parameters of the alignment film polymer by introducing specific groups (formula 1 or 2) that alter the interaction with liquid crystal molecules. This changes the anchoring characteristics to suppress pre-tilt while maintaining high-speed response capabilities through high Δn liquid crystal and narrow cell gap design.
Solution Approach 2:
The alignment film is designed as a composite material containing polymer with specific functional groups (formula 1 or 2) that combine weak anchoring properties with enhanced alignment control. This composite structure enables simultaneous achievement of high-speed response and stable horizontal alignment by balancing the competing requirements.
2Use of energy by moving object
If weak anchoring alignment film is used to reduce power consumption, then energy consumption is improved, but alignment control becomes difficult leading to pre-tilt and display defects
Solution Approach 1:
The patent changes the chemical parameters of the alignment film by incorporating polymer with specific groups (formula 1 or 2) that modify the anchoring strength. This adjustment maintains weak anchoring for low power consumption while improving alignment control capability through optimized molecular interactions at the interface.
3Illumination intensity
If liquid crystal molecules with biphenyl or terphenyl skeleton are used to increase Δn, then birefringence is improved, but pre-tilt increases due to interaction with weak anchoring alignment film
Solution Approach 1:
The patent modifies the alignment film polymer structure with specific groups (formula 1 or 2) that change the interfacial interaction parameters. This allows use of high Δn liquid crystal molecules (biphenyl or terphenyl skeleton) while suppressing the pre-tilt effect through optimized anchoring characteristics.
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 design achieves stable horizontal alignment, low power consumption, and high-speed response with reduced pre-tilt and improved reliability, with reduced anisotropy of dielectric constant anisotropy, and a faster response time, even under varying temperatures and frequencies.
Implementation Method 1
liquid crystal panels have been proposed that utilize weak anchoring alignment films, which have a weaker anchoring strength than conventional alignment films
Implementation Method 2
when a photoalignment film for horizontal alignment is placed on one side of the liquid crystal layer instead of a rubbing alignment film
Implementation Method 3
high Δn liquid crystal and low-viscosity (low γ1) liquid crystal are commonly used
Implementation Method 4
low-viscosity (low γ1) liquid crystal are commonly used
Implementation Method 5
a second compound having a structure in which at least one polar group selected from the group consisting of F, CN, SCN, and OCnH2n+1 is bonded to a phenylene ring
Data Source
AI summary
Provided is a liquid crystal panel in which the liquid crystal has excellent horizontal alignment properties and excellent high-speed response. The liquid crystal panel includes a pair of substrates and a liquid crystal layer between the pair of substrates. At least one of the pair of substrates includes an alignment film on a surface facing the liquid crystal layer. The alignment film contains a polymer having at least one of a group represented by the following formula (1) or a group represented by the following formula (2). The liquid crystal layer contains a liquid crystal material that contains a first compound represented by the following formula (3) and a second compound having a structure in which at least one polar group selected from the group consisting of F, CN, SCN, and OCnH2n+1 is bonded to a phenylene ring.