The "liquid crystal" in the LCD liquid crystal screen is one of the three main materials of the LCD liquid crystal screen, and its role is very great.

1. The basic concept of LCD screen:

Liquid crystal as a new physical form. It was discovered by Austrian scientist Friedrich Reinitzer in 1888. When the substance is heated until the crystal melts, it changes into a milky white turbid liquid. If the heating is continued, the milky white liquid will turn into a completely transparent liquid. This phenomenon also occurs correspondingly during the cooling process. Observed with a polarizing microscope, it is found that this milky white liquid is different from ordinary liquids, and presents optical anisotropy, that is, the molecules in the object have a certain degree of orderly arrangement, which is different from the traditional concept of solid and liquid, and is defined as liquid crystal.

2. The main application of liquid crystal characteristics:

(1) Relative temperature T: It must be ensured that within the required temperature range, the entire system is a nematic phase, and no crystallization phenomenon can occur, nor can other phase states appear, such as smectic phase.

(2) Dielectric coefficient △ε: Adjust the size of △ε to meet the user's requirements for the threshold voltage.

(3) Optical anisotropy △n: Adjust the size of △n to meet the user's requirements for different box thicknesses.

(4) Pitch P: An important parameter to determine the thickness of the box and the amount of chiral agent added.

3. Matters needing attention in the use of LCD:

(1) Influence of ultraviolet light

Destroy the C-C bond, break the C chain of the polymer, and affect the above-mentioned properties.

(2) Influence of temperature

Liquid crystals are less sensitive to temperature than to ultraviolet light. During use, try to reduce the heating time of liquid crystals as much as possible, and avoid heating to a higher temperature, such as not higher than the clearing point of 35°C.

(3) Environmental impact

A small amount of conductive material is enough to reduce the resistivity, because the resistivity of liquid crystal is 1011-1012Q/cm2.

(4) Influence of container

It is best to use hard glass, a glass high in borosilicate. The material of ordinary glass bottles is sodium glass, and the resistivity of liquid crystals in glass containers will decrease. The best conditions for LCD liquid crystal storage: sealed, dark, dry, room temperature.