TN – Twisted Nematic

Twisted Nematic (TN) consist of liquid crystal material sandwiched between two polarising plates which are attached to the outside of two glass plates, one upper and one lower. These polarisers have their planes orientated at right angles (90°) to each other. When the light passes through the first polariser, the liquid crystal twists the light at 90° before reaching the the second polariser, allowing no light to pass through.

Response times of the TN based liquid crystal is far too slow to support fast animations or full-frame-rate video. TN Displays are very low cost, low power displays which can have certain viewing angle limitations, depending on multiplex rates. These limitations can be overcome with an or STN display.

Principles of a TN display

In its natural state, the light passing through the first polariser cannot pass through the second polariser due to the different orientations of the filters. When voltage is presented to the molecules, the orientation is altered and bends the light between the two filters so it matches the orientation of the second filter as well. If the orientation is completely changed then the light is passed unfiltered.

TN display

TN display

A low cost LCD display developed in the 1980s with variants such as STN, FSTN, FFSTN, DSTN etc