Fast-response twisted nematic liquid crystal displays with ultrashort pitch liquid crystalline materials

A new method to improve the response time of twisted nematic (TN) liquid crystal displays (LCDs) with liquid crystalline (LC) materials of pitch length shorter than twice the cell gap is proposed. It was known that by using LC materials possessing shorter pitch length, the response time could be improved. However, in previous studies, the pitch length p was limited to values larger than the twice of the cell gap d. This is because 90 degrees TN arrangements become unstable and transform into a 270 degrees super-twisted nematic (STN) arrangement for p < 2d. It was found that by applying voltage to 270 degrees STN arrangement, the 90 degrees TN arrangement could be formed and the obtained TN-LCDs could be stabilised by photopolymerisation. This is because the 270 degrees STN arrangement contains splay deformation. The obtained TN-LCDs exhibit a fast response. By using this method, fast-response TN-LCDs could be realised maintaining moderate driving voltage.