TFD screen and STN screen

TFD screen

TFD is short for Thin Film Diode. Since TFT is power-intensive and expensive, which increases the availability and cost of mobile phones, TFD technology has been developed by seiko Epson, a mobile screen giant, specifically for mobile phone screens. It is a compromise between TFT and STN, with better brightness and color saturation than STN, but less power than TFT. TFD features "high image quality, ultra-low power consumption, miniaturization, dynamic image display capability and fast response time". The display principle of TFD is that each pixel on LCD is equipped with a separate diode as the control source. Due to such a separate control design, each pixel will not interact with each other, so that the dynamic screen and bright colors can be displayed on the Ssreen of TFD. Like TFT, TFD is also an active matrix driver.

The STN screen

STN, short for Super Twisted Nematic, is the most common LCD we've ever seen, because the grey scale phones we've used in the past have STN screens. Compared with TFD, STN liquid crystal is a passive matrix LCD device, which has the advantage of low power consumption and the biggest advantage of power saving. The principle of color STN display is to add a color filter to the traditional monochrome STN Liquid crystal display device, and divide each pixel in the monochrome display matrix into three sub-pixels, and display the three primary colors of red, green and blue through the color filter respectively, then the color screen can be displayed. Different from TFT, STN is Passive LCD and can display 65536 colors at most.

Leaving aside the gray-scale STN, STN is now mainly divided into CSTN and DSTN. The CSTN (Color STN) is usually a transmissive light. The transmissive screen is illuminated by an external source, called a backlight, which is mounted on the back of the LCD. Transmission type LCD displays well under normal and dark light, but in the outdoors, especially in daylight, it is difficult to distinguish the content of the display and the backlight needs power to produce lighting light, which consumes electrical power.