Stands for "Thin Film Transistor."
A TFT is a type of transistor used in active-matrix LCD screens. TFT LCD screens use a separate transistor to control each pixel in the display. They allow the electrical current that controls each pixel to turn on and off quickly, which decreases response time and makes on-screen motion smoother. TFT LCDs are often used as computer monitors, televisions, mobile phone screens, and other flat-panel color displays.
The name "Thin Film Transistor" is derived from the manufacturing process. The manufacturer first applies thin films of a semiconductor (like amorphous silicon) and dielectric materials to a flat, non-conductive surface (like glass). Unneeded silicon is etched away, leaving only a grid of transistors and the transparent glass surface. These transistor panels are thin enough to fit between a polarized backlight and the layer of liquid crystals. These transistors apply an electrical current to the liquid crystals, altering their arrangement to block light in certain ways. The light then passes through other layers of the screen, including a color filter and polarized light filter, to display the final image.
Types of TFT Displays
Not all TFT LCD screens are made the same. There are several types of TFT panels, made by distinct methods, and with different performance characteristics. The two most common types are TN and IPS.
- Twisted Nematic (TN) panels contain liquid crystals that twist as an electric current is applied. As the crystals twist, they allow varying amounts of polarized light to pass through. TN panels are the easiest type of TFT LCD to produce and offer the quickest response times. However, TN panels don't display colors as accurately as other types of panels, particularly when viewed at an angle.
- In-Plane Switching (IPS) panels contain liquid crystals that don't twist but instead reorient themselves while remaining parallel to their original planar position. As the crystals realign, they allow varying amounts of polarized light through. IPS panels are more expensive to produce than TN panels, require more power to operate, and have slower response times. However, they are more accurate at color reproduction, even when viewed at an angle.