What is STN?

- Mar 25, 2020-

STN (Super Twisted Nematic) uses an electric field to change the arrangement of liquid crystal molecules that have been twisted above 180 degrees to change the optical rotation state. The applied electric field changes the electric field by means of progressive scanning. During the process of the electric field repeatedly changing the voltage, each point The recovery process is slower, resulting in afterglow. It has the advantage of low power consumption and the biggest advantage of power saving.

 

Introduction

 

The display principle of color STN is to add a color filter to the traditional monochrome STN LCD display, and divide each pixel in the monochrome display matrix into three sub-pixels, and display the red, green, and blue three through the color filter. The primary color displays a color picture. Different from TFT, STN is a passive LCD, which can display up to 65536 colors.

 

The main classification of STN

 

It is mainly divided into ordinary STN, FSTN, CSTN and DSTN.

 

Ordinary STN means that the LCD rotates 180 ~ 270 degrees in the LCD screen, and ordinary polarizers are affixed on the LCD screen. Due to the dispersion, the background color of the LCD screen will show a certain color, usually yellow-green or blue. Yellow-green or blue.

 

FSTN (Film + STN), in order to improve the background color of ordinary STN, a layer of compensation film is added to the polarizer to eliminate dispersion and realize black and white display.

 

CSTN (Color STN), color STN, on the basis of FSTN technology, add a layer of RGB color film to achieve color display, and generally has a higher number of drive channels.

 

DSTN (Double STN), double-layer STN, one of which is the driver layer and the other is the compensation layer. It belongs to STN black and white technology. Compared with FSTN, it has higher contrast and can automatically compensate for dispersion with temperature. High contrast of range.

 

STN technology principle

 

The display principle of STN is similar to that of TN. The difference is that TN twisted nematic field effect liquid crystal molecules rotate the incident light 90 degrees, while STN super twisted nematic field effect rotates the incident light 180 ~ 270 degrees. It should be explained here that the simple TN liquid crystal display itself only has two conditions of light and dark (or black and white), and there is no way to change the color. However, if a color filter is added to a conventional monochrome STN LCD, and any pixel of the monochrome display matrix is divided into three sub-pixels, the color filters are passed through Display the three primary colors of red, green, and blue, and then adjust the ratio of the three primary colors to display the colors of the full color mode. In addition, the larger the screen size of a TN-type LCD, the lower the screen contrast, but with the improved technology of STN, it can make up for the lack of contrast.