Smectic A Liquid Crystal Material for Residual Image Elimination
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Solution Overview
Problem
Siloxane smectic A phase liquid crystal materials exhibit strong memory effects, leading to residual images and low contrast in displays due to high drive voltage and narrow temperature range, as well as low birefringence, which limits their application in optical display materials.
Innovation Solution
A smectic A phase liquid crystal material comprising heterocyclic compounds and ester compounds, which induce the smectic phase, increase conductivity, and enhance birefringence, allowing for low drive voltage operation (20-50 V) and high contrast without residual images.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If siloxane smectic A phase liquid crystal materials are used, then the drive voltage is reduced and temperature range is broadened, but residual images occur and contrast is low
Solution Approach 1:
The patent changes the chemical composition parameters of the liquid crystal material by introducing heterocyclic compounds with specific molecular structures (containing nitrogen, oxygen, or sulfur atoms in six-membered rings) and adjusting the ratio of smectic phase-inducing compounds to nematic phase compounds. This parameter change eliminates the strong memory effect of siloxane materials while maintaining broad temperature range, thereby resolving the residual image problem without sacrificing temperature adaptability
Solution Approach 2:
The patent creates a composite liquid crystal formulation by mixing smectic phase-inducing compounds (heterocyclic compounds with specific functional groups) and nematic phase compounds in controlled ratios (30-70 wt% smectic phase inducer). This composite approach combines the advantages of both phase types: the smectic phase provides broad temperature range while the nematic phase reduces memory effect, eliminating residual images and improving contrast
2Use of energy by moving object
If siloxane smectic A phase liquid crystal materials are used, then the drive voltage is reduced, but contrast is low due to low birefringence
Solution Approach 1:
The patent changes the optical parameters of the liquid crystal material by selecting heterocyclic compounds with high birefringence coefficients (Δn > 0.15). The specific molecular structure parameters (ring type, substituent groups, chain length) are optimized to maximize birefringence while maintaining smectic A phase stability. This enables high contrast (>10:1) to be achieved at low drive voltages (20-50 V), simultaneously improving both energy efficiency and optical performance
3Device complexity
If conventional smectic A phase materials (8CB, 8OCB) are used, then the material structure is simple, but drive voltage is high and temperature range is narrow
Solution Approach 1:
The patent develops a composite liquid crystal formulation containing multiple components: smectic phase-inducing heterocyclic compounds (30-70 wt%), nematic phase compounds (10-40 wt%), and additives (1-20 wt%). This multi-component composite structure broadens the temperature range to -20°C to +85°C and reduces drive voltage to 20-50 V, significantly improving upon conventional single-component materials while maintaining manageable structural complexity through systematic formulation design
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 new smectic A phase liquid crystal formulation effectively eliminates residual images and achieves high contrast (>10:1) while reducing drive voltage, enhancing the performance of smectic liquid crystal displays.
Implementation Method 1
All the liquid crystals have the dielectric anisotropy, and the liquid crystal molecules can be driven by an electric field
Implementation Method 2
A smectic A phase liquid crystal material comprising at least one heterocyclic compound of Formula (III), (IV), (V), (VI) or (VII)... which induce the smectic phase
Implementation Method 3
since the birefringence of the siloxane smectic A phase materials is very low (Δn≈0.08)... the smectic A phase liquid crystal formulation with siloxane as the main body has a low birefringence
Data Source
Figure 1-a~2
Figure 3-a~3-c
Figure 4~6
AI summary
The present invention relates to a smectic A phase liquid crystal material, which contains at least one heterocyclic compound of Formula (I): where X and Z are a phenyl ring, F is a fluorine atom, and any one of hydrogen atoms on the phenyl ring may be substituted with a fluorine atom; in the case of Y being a phenyl ring, T is a nitrogen atom, and any one of carbon atoms on the phenyl ring may be substituted with a nitrogen atom; and in the case of Y being a cyclohexyl ring, T is an oxygen atom, a sulfur atom and/or a boron atom, and any one of carbon atoms on the cyclohexyl ring may be substituted with an oxygen atom, a sulfur atom and/or a boron atom. The smectic A phase liquid crystal material of the present invention may further contain at least one ester compound of Formula (II) and an ionic compound. By using the smectic A phase liquid crystal material in a display device, a displayed image can be completely erased without any residual images after long-term placement or long-term drive, the contrast is generally higher than 10, and the drive voltage is generally 20 to 50 V.