TFT, Thin Film Transistor, technology uses Transistor switching to control a display array.
A thin-film transistor is a special kind of field-effect transistor made by depositing thin films of an active semiconductor layer as well as the dielectric layer and metallic contacts over a supporting (but non-conducting) substrate which is usually glass.
The circuit layout of a TFT is very similar to the one used in a DRAM memory. However, rather than building the transistors out of silicon which has been formed into a crystalline wafer, they are fabricated from a thin film of silicon deposited on a glass panel. (TFT can also be placed on a plastic backing in E Ink Mobius display.) A transistor is connected to each pixel and a matrix selection of the X/Y array is used to select an individual crystal. These devices store the electrical state of each pixel on the display while all the other pixels are being updated. This method provides a much brighter, sharper display than a passive matrix of the same size.