TFT LCD (Thin Film Transistor Liquid Crystal Display) has a sandwich-like structure with liquid crystal filled between two glass plates.
TFT Glass has as many TFTs as the number of pixels displayed, while a Color Filter Glass has color filter which generates color. Liquid crystals move according to the difference in voltage between the Color Filter Glass and the TFT Glass. The amount of light supplied by Back Light is determined by the amount of movement of the liquid crystals in such a way as to generate color.

　 It uses liquid crystal to control the passage of light. The basic structure of a TFT-LCD panel may be thought of as two glass substrates sandwiching a layer of liquid crystal. The front glass substrate is fitted with a color filter, while the back glass substrate has transistors fabricated on it. When voltage is applied to a transistor, the liquid crystal is bent, allowing light to pass through to form a pixel. A light source is located at the back of the panel and is called a backlight unit. The front glass substrate is fitted with a color filter, which gives each pixel its own color. The combination of these pixels in different
colors forms the image on the panel.
　A TFT substrate is composed of a matrix of pixels and ITO region ( a transparent electric conducting film)each with a TFT device and is so called array. Thousands or millions of these pixels together create an image on the display. The diagram below shows the simple structure of a pixel.No matter how the design of the TFT panel changes or the process modified, it's structure have to contain TFT devices and LC control region ( ITO film for transmissive type of LCD, metal such as AI is used for reflective type of LCD).
TFT device is a switching device, which functions to turn each individual pixel on or off hence controlling the number of electrons flow into the ITO zone. As the number of electrons reaches the expected value, TFT turns off and these electrons can be kept within the ITO zone.