Twisted nematic (TN) technology for LCDs
Light and dark
TN flat screens are constructed from multiple layers. The ultra-thin layer of liquid crystal mixture, twisted by 90°, is located between two thin panels of glass coated with clear electrodes. Polarization filters are found on the outside of the glass plates, while on the inside there are color filters, transparent electrodes, and a two-sided layer for orienting the LC molecules. The thin layer of liquid crystals, around four to eight micrometers thick, is the heart of every LC display. In conjunction with polarization filters, it works as a "light valve" for the backlight. The first polarization filter allows only a specific oscillation level of light to pass through. The light then meets the liquid crystals. When
The light follows this
The TN cell was invented around 1971 by James Fergason, Martin Schadt, and Wolfgang Helfrich.