Liquid Crystal Displays (LCD)
STN vs TFT
LCD
Liquid Crystal Displays (LCD) are made up of cells which twist to change their polarization direction in response to an electrical voltage. This causes a change in the amount of light that is allowed to pass though and form each pixel.
There are currently two main types of Liquid Crystal Displays: STN and TFT.
STN
Super Twisted Nematic (STN) screens are an improvement over the original Twisted Nematic(TN) screens. STN screens use a fluid with a greater twist (200° or more). It can be used in larger matrix displays and has better contrast and viewing range than TN.
Super Twisted Nematic LCDs use a passive matrix screen technology that has no active or controlling element inside the display cell. Pixels are controlled by energizing the appropriate row and column drive lines of the matrix from outside the display, resulting in a slow frame rate.
STN screens have limited color range, and viewing angle (~15 degrees max).
TFT
With Thin Film Transistor (TFT) LCDs, each pixel is controlled by one to four transistors. Typically one transistor is used for each of the RGB color channels. Because of this direct control technique, TFT screens are sometimes called Active-Matrix LCDs.
TFT technology provides more accurate color control, allowing it to display more colors
TFT screens also offer a wider viewing angle range (30 to 70 degrees) than the other popular types of LCDs.
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