Liquid Crystal Composition for One-Drop-Fill Stability
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Solution Overview
Problem
Liquid crystal display devices face challenges in achieving a liquid crystal composition with positive dielectric anisotropy, wide temperature range, low viscosity, high specific resistance, and high voltage holding ratio, while also requiring stable production processes to prevent defects like screen burn-in and droplet stains.
Innovation Solution
A liquid crystal composition containing specific compounds represented by General Formulae (i) and (ii), which are optimized in terms of concentration and structure to provide the desired properties, allowing for stable and continuous dropping during the one-drop-fill technique, ensuring high-yield production of liquid crystal display devices with improved display quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a liquid crystal composition with positive dielectric anisotropy is used to achieve high voltage holding ratio and high specific resistance, then display quality is improved, but the composition becomes sensitive to impact and pressure change during the one-drop-fill process
Solution Approach 1:
The patent modifies the molecular structure of liquid crystal compounds by changing physical and chemical parameters - specifically introducing fluorine atoms at particular positions in the molecular structure and adjusting the balance between compounds with positive and neutral dielectric anisotropy. This changes the physical properties to reduce sensitivity to impact while maintaining voltage holding ratio
Solution Approach 2:
The patent uses a composite liquid crystal composition comprising multiple compounds - specifically at least one compound of Formula (i) with positive dielectric anisotropy and at least one compound of Formula (ii) with neutral dielectric anisotropy. This composite approach allows the composition to achieve high voltage holding ratio through the positive Δ∈ compound while the neutral Δ∈ compound provides stability and reduces sensitivity to impact
2Manufacturing precision
If the amount of liquid crystal composition to be dropped is precisely controlled for small-size devices, then display quality is improved, but it becomes difficult to control variation from the optimum amount
Solution Approach 1:
The patent changes the physical parameters of the liquid crystal composition, specifically adjusting viscosity and density through molecular structure modification. These parameter changes make the composition less susceptible to variation during the one-drop-fill process, enabling precise control of the dropped amount even for small-size devices while maintaining high production yield
3Ease of manufacture
If liquid crystal composition is dropped using one-drop-fill technique to adapt to large substrate sizes, then manufacturing process is simplified, but droplet stains are generated degrading display quality
Solution Approach 1:
The patent modifies the physical parameters of the liquid crystal composition, specifically adjusting surface tension and viscosity through molecular structure changes. These parameter modifications enable the composition to be dropped without generating droplet stains, maintaining display quality while preserving the simplicity of the one-drop-fill manufacturing process
Solution Approach 2:
The patent converts the potential harm of the one-drop-fill process (droplet stain generation) into a benefit by carefully selecting and optimizing the liquid crystal composition. The composition is designed to be ideally suited for dropping, transforming a potentially defective process into a high-quality manufacturing method
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 optimized liquid crystal composition achieves improved resistance to low temperature, high specific resistance, and high voltage holding ratio, enabling high-yield production of liquid crystal display devices with reduced defects, suitable for applications in IPS and FFS types.
Implementation Method 1
a liquid crystal composition having a positive Δ∈ is used in horizontal alignment-type displays such as a TN type, an STN type, and an IPS (in-plane switching) type
Implementation Method 2
a liquid crystal composition having a positive Δ∈ has therefore further increased. In all types of driving, however, there have been demands for low driving voltage, a quick response, and a broad range of operation temperature
Data Source
AI summary
It is an object of the present invention to provide a liquid crystal composition having a positive Δ∈, the liquid crystal composition also having a liquid crystal phase in a wide temperature range, a good resistance to resolution at low temperature, an excellent adaptability to an ODF process, a high specific resistance and voltage holding ratio, and stability to heat and light. In order to achieve this object, a liquid crystal composition containing compounds represented by Formulae (i) and (ii) is provided.(where Ri1 represents an alkyl group having 1 to 5 carbon atoms or an alkenyl group having 2 to 5 carbon atoms).