LCD display must according to the requirements of the liquid crystal molecules in a certain direction oriented graphics in the electric field, and with the plane at an angle, which is called "pre-tilt angle." The liquid crystal molecules can be ordered liquid crystal cell is applied to the surface of the alignment film, the film is formed of such a material is a liquid crystal aligning agent. Now used as a liquid crystal aligning agent are polymer materials industry. The polymer film in a certain direction such friction after such liquid crystal molecules have the ability. But not just any polymer film after rubbing the liquid crystal molecules can obtain the required pre-tilt angle. Aligning agent used as a polymer material should have a choice in the structure, in order to meet the requirements needed for the pre-tilt angle. Furthermore, since the need for processing and use of properties, should also meet the following conditions:
1. For the performance oriented long-term use and stability, as the molecular alignment agent must have a high thermal stability.
2. ITO has good bonding properties, and will not come off in the wash after the friction.
3. Aligning agent solution has a good leveling in the coating when.
4. Good chemical stability, physical contact with, such as liquid crystal stable, but also has good storage stability.
5. Sufficient mechanical strength.
6. In order to ensure good insulation properties, aligning agent should have a low ionic content.
7. Good transparency.