After some substances are melted or dissolved by solvents, although they lose the rigidity of solid substances, they gain the fluidity of liquids and retain the anisotropic orderly arrangement of some crystalline substances, forming a kind of both crystals. And the intermediate state of the partial properties of the liquid, This kind of oriented and ordered fluid that exists during the conversion from solid to liquid is called liquid crystal. The definition is relaxed to include substances that can display liquid crystal phase in a certain temperature range and normally crystallize at lower temperatures. For example, liquid crystal can flow like a liquid (fluidity), but its molecules are oriented and ordered like a road (anisotropy). There are many different types of liquid crystal phases, which can be distinguished by their different optical properties (such as birefringence). When using a polarized light source, when observed under a microscope, different liquid crystal phases will appear with different textures. Different textures in the texture contrast area correspond to different liquid crystal molecules. However, the molecules have better orientation and order. The liquid crystal material may not always be in the liquid crystal phase (just as water can turn into ice or water vapor).
Liquid crystal can be divided into thermotropic liquid crystal and lyotropic liquid crystal. Thermotropic liquid crystal refers to a liquid crystal formed from a single compound or a homogeneous mixture of a few compounds. A substance that usually shows a liquid crystal phase within a certain temperature range. The molecular weight of a typical long rod-shaped thermotropic liquid crystal is generally about 200~500g/mol. Lyotropic liquid crystal: It is a liquid crystal formed by two or more compounds including solvent compounds. The liquid crystal phase appears when the concentration of solute molecules in the solution is within a certain range. Its solvent is mainly water or other polar molecular liquid agents. The main reason for the long-range order of the molecular arrangement in this liquid crystal is the interaction between the solute and the solvent molecules, and the interaction between the solute molecules is secondary. A lyotropic liquid crystal is a liquid crystal formed of two or more compounds including a solvent compound.
When the electricity is turned on, the arrangement becomes orderly, making the light easy to pass; when the electricity is not turned on, the arrangement is chaotic, preventing the light from passing. Let the liquid crystal block or allow light to penetrate like a gate. Technically speaking, the LCD panel contains two very delicate soda-free glass materials, called Substrates, with a layer of liquid crystal in between. When the light beam passes through this layer of liquid crystal, the liquid crystal itself will stand in rows or twist in an irregular shape, thus blocking or allowing the light beam to pass smoothly. Most liquid crystals are organic compounds, composed of long rod-shaped molecules. In the natural state, the long axes of these rod-shaped molecules are roughly parallel. When the liquid crystal is poured into a well-processed slotted plane, the liquid crystal molecules will be arranged along the grooves, so if the grooves are very parallel, the molecules are also completely parallel. Liquid crystal is an intermediate substance between the crystalline state and the liquid state. It has some characteristics of both liquid and crystal, showing some unique properties