The main difference between TN and STN in structure is the twist angle of liquid crystal molecules. The twist angle of TN type is 90 degrees, and the twist angle of STN type is 90 degrees to 270 degrees. Depending on the twist angle and the angle of the polarizer, the STN type can have yellow-green mode, blue mode, gray mode and so on. And TN has positive and negative and so on. Compared with TN, STN has higher drive capability and better electro-optical performance.

The FSTN type is to add a compensation film on the basis of the STN, which can compensate the interference color of the STN and realize its true black and white display effect. The angle of the compensation film is different, so there can be positive (black characters on a white background) and negative (white characters on a black background) displays.

Holographic: FSTN adds a layer of holographic film on the basis of STN, which can make the display effect more pleasing and beautiful, and also has higher electro-optic parameters.

Its main process introduction:

Photolithography: Electrodes of required shape are formed on the surface of ITO.

More important processes in the photolithography process:

Orientation layer coating: Uniform coating on the surface of the glass - an orientation layer.

Orientation layer rubbing: Use flannelette to rub a groove on the surface of the alignment layer, so that the liquid crystal molecules can be arranged in the required direction.

Silk-screen printing into a box: Use silk-screen glue to bond the upper and lower pieces of glass together, and then form an empty box.

Cutting and cracking: Cutting a large piece of glass into a small liquid crystal cell for easy filling of liquid crystal.

Liquid crystal test: Adjust the liquid crystal according to the background color and driving conditions required by the customer, and determine the liquid crystal that can meet the requirements.

Pouring and sealing: Pour the adjusted liquid crystal into the empty box, and then use sealing glue to seal the box.

Cleaning: Clean off the liquid crystal that remained on the LCD screen before.

Optical table and electrical test: Check the LCD screen on the optical table for defects such as appearance, pollution, and uneven box thickness. Electric test to check whether the LCD power-on display is normal.

Polarizer: Paste polarizers that meet the requirements according to some different LCDs.

Inspection and reliability experiment: Carry out the final inspection to ensure that the appearance and electrical properties of the LCD can meet the requirements of customers.

The reliability test is divided into high temperature and high humidity test, high temperature test, low temperature test, high and low temperature impact test, high temperature and high humidity.