Various liquid crystal molecular structure and the nature of the relationship TFT Display Module

Generally, the elongated rod-like or planar parallel to the beneficial molecules, and molecules of polarizable groups or polar group is related to the interaction between molecules, thereby affecting the phase transition temperature.
Center of the liquid crystal molecules of the liquid crystal properties of the bridge bond influence. The chemical stability of the liquid crystal, the first key depending on the nature of the center bridges, such as benzyl * (benzylidene) type liquid crystal to the center of the bridge bond is-CH == N-, it is susceptible to hydrolysis or oxidation, are extremely sensitive to water. In another example, the compound is easily oxidized even chlorine, especially in the light of the role. Others such as containing double bonds, triple bonds stilbene diphenyl acetylene, cinnamate and other derivatives are also easy to be oxidized and easy polymerization, the chemical stability is relatively poor, and under ultraviolet light may also be due to polymerization or cracking the loss characteristics of the liquid crystal.
Discard the first liquid crystal molecules in the center of the bridge bond, synthesis of biphenyl liquid crystal, liquid crystal stability than the other, indicating that the center bridges constituting the liquid crystal is not the only condition. Biphenyl liquid crystal is the most commonly used as a liquid crystal. Coding System lcd module
The spatial configuration of the liquid crystal molecules affect the thermal stability of liquid crystal, and other characteristics. Stilbene is planar conformation, azoxy molecular plane slightly twisted, distorted benzyl * LCD with large, clear them below stilbene. The clearing point of the oxidation azo rather peculiar, although it has a planar structure of the crystal, it is very likely when the liquid crystal phase, to a non-planar arrangement of molecules, molecular distortion, resulting in lower molecular rigidity, resulting in lower clearing point. Esters LCD weak conjugation it has the lowest clearing point. In addition, because of diphenyl acetylene-based liquid crystal molecular orbitals common yoke effect, so thermal stability than benzyl * class LCD.
In general, if the bridging connection is rigid, is conducive to the formation of a liquid crystal phase, branched chain end groups are generally more negative. Chain length of end groups to more subtle. If the rigid portion of the molecule lead to a strong interaction anisotropy, increase the bond length is not conducive to the stability of liquid crystal phase, if the rigid portion does not cause a strong steric hindrance, increasing chain length favorable interaction anisotropy.
Increased number of rings, which greatly increases the thermal stability of the liquid crystal, for example: low temperature lcd
When n = 1, the clearing point of 121 ℃; when n = 2, the clearing point of 297 ℃, a similar situation with multi-substituted benzene ring or a fused ring, also increased the stability of the liquid crystal.
Cis-trans structure on the thermal stability of the liquid crystal has a great influence. The trans-configuration of the rigid structure have a linear molecule, thus showing a liquid crystal phase, and a non-linear cis structure and a flexible molecular structure, and thus does not exhibit a liquid crystal phase , their molecular structure shown in Figure 18 . For example, many azo compounds, cinnamic acid esters, chlorinated diphenyl allyl, phenyl cyclohexane, hexane bicyclic compounds are trans LCD cis not.