LCD is made of a cell that contains liquid crystal material sandwiched between two glass plates. Lines and columns of the transparent conductor are configured on the inner surfaces of the cell. A transparent polarizing film is attached to the top glass plate. Pre-tilted angle is to twist LC for the direction. LCD is classified by difference in twist angle; TN(90°) and STN(160~240°).

The weakness of STN LCD, when compared with TN, is that it is difficult to display black and white because STN LCD mainly uses properties of birefringence. Thus, display becomes yellow mode, blue mode, and gray mode according to the different conditions. Optical compensation is required to neutralize these color distortion.