Bistable twisted nematic (BTN) liquid crystal displays (LCDs) traditionally have bistable twisted states that differ in twist angle by 2π. Unfortunately, these 2π-BTN displays have an intermediate twist state in π which is more stable than the two metastable states 0 and 2π. So, the 2π-BTN has not been useful....[ Read more ]

Bistable twisted nematic (BTN) liquid crystal displays (LCDs) traditionally have bistable twisted states that differ in twist angle by 2π. Unfortunately, these 2π-BTN displays have an intermediate twist state in π which is more stable than the two metastable states 0 and 2π. So, the 2π-BTN has not been useful.

Recently, different researches on π-BTN have been conducted. In this thesis, truly bistable twisted nematic liquid crystal display has been fabricated using photoalignment technology. This display can be switched between the -22.5° and 157.5° twist state by breaking of the anchoring on one of the substrates. The application of a photoalignable polymer SDA-1 was able to achieve the weak anchoring condition necessary for switching. Both theoretical and experimental results show that this mode has excellent contrast ratio and wide viewing angles.