The main difference between TN and STN in the structure is the twist angle of the liquid crystal molecules. The twist angle of the TN type is 90 degrees, and the twist angle of the STN type is 90 degrees to 270 degrees. Depending on the twist angle and the angle of the polarizer, the STN type can have a yellow-green mode, a blue mode, a gray mode, and so on. And TN has positive and negative characteristics and so on. STN has a higher number of driving capabilities than TN and its better electro-optical performance.
For the FSTN type, a compensation film is added to the foundation of the STN, which can compensate for the interference color of the STN and realize its correct black and white display effect. The angle of the compensation film is different, so there can be positive (black text on a white background) and negative (white text on a black background) display.
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-optical parameters
The main process introduction:
1 Photolithography: An electrode of the required shape is formed on the surface of the ITO.
2 The more important processes in the photolithography process:
3 Orientation layer coating: Coat a layer of orientation layer evenly on the surface of the glass.
4 Orientation layer rubbing: Use flannel to rub a groove on the surface of the orientation layer so that the liquid crystal molecules can be arranged in the required direction.
5 Silk screen into a box: The upper and lower two pieces of glass, use silk screen glue to glue them together, and then form an empty box.
6 Cutting cracks: Cut a large piece of glass into a small liquid crystal cell to facilitate the infusion of liquid crystal.
7 Liquid crystal test: According to the background color and driving conditions required by its customers, the liquid crystal is modulated, and the liquid crystal that can meet the requirements is determined.
8 Filling and sealing: Fill the adjusted liquid crystal into the empty box, and then use the sealing glue to seal the box.
9Cleaning: Clean the remaining liquid crystal on the LCD screen before.
10 Optical table, electrical measurement: Check the LCD screen on the optical table for defects such as appearance, pollution, and uneven thickness of the box. Electrical test to check whether the LCD power-on display is normal.
11 Polarizer: According to some different LCDs, paste the polarizer that can meet the requirements.
12 Inspection and reliability experiment: Carry out the shipment inspection to ensure that the appearance and electrical properties of the LCD can meet customer requirements.
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 test.
