Active-matrix liquid-crystal display

The term active - matrix display or AMLCD (short for engl. Active matrix liquid crystal display) is mainly used for liquid crystal displays, containing a matrix of thin film transistors with which LCD pixels can be controlled. Each individual pixel has a circuit with active components (usually transistors) and power connectors.

Pioneers of this kind of matrix addressing of LCDs were Bernard J. Lechner ( RCA Laboratories ), T. Peter Brody and Fang - Chen Luo (both at Westinghouse Electric). Lechner invented the concept and implemented a prototype with discrete components (FET transistors and capacitors) in 1968. Brody and Luo in 1974 could imagine a first active-matrix LCD with thin film transistors in an integrated form.

The each pixel associated with sample-and- hold circuit has two important functions:

Both effects ( arbitrarily small control voltage and compensating parasitic capacitance ) cause active matrix displays the constant desire for smaller pixels (PDAs, mobile phones with color display ) or higher pixel numbers (notebook, digital camera, display, liquid crystal display ) as the only LCD form be able to meet.

By using IPS - LCD cells is also the wide angle of the display against Super - Twisted Nematic (STN ) - improves passive - matrix displays.

The most important representative of active matrix displays are displays with thin film transistors (English Thin Film Transistor TFT), in which the transistor is deposited directly on the glass substrate. OLED displays are also implemented as active matrix displays. As long as no high-frequency transistors, made ​​of plastic are also possible, an OLED requires a similar amplifier structure on a glass or silicon-based, such as a conventional LCD with the difference that a light emitting diode with a current, not driven by a voltage. Therefore, low impedance, narrow leads in the display area of ​​a challenge.

Displays with electronic paper also included a TFT active matrix driving of the pixels.