Screen Print Technology Ltd of Llantrisant, mid-Glamorgan has made a breakthrough which, it claims, will render glass liquid crystal displays obsolescent within a few years. The new display is the Nematic Curvilinear Aligned Phase liquid crystal display, called NCAP for short. Whereas traditional displays use a continuous layer of liquid-crystal coating sandwiched between aligned glass plates, NCAP products are made up of micron-sized droplets of liquid crystal dispersed within a latex paint base. The emulsion then coats a polyester base film sandwiched between polyester sheets coated with transparent conductors made of Indium-Tin Oxide. At this point the sheet is opaque and its colour is deepened to black by adding dyes to the emulsion. When a voltage is applied to the polyester sheet, the nematic molecules behave, analogously, like venetian blinds in that they align with the electronic field, reducing their refractive index as they do so, and enable light to pass through them. When this happens the polyester sheet becomes transparent. NCAP thus has two main advantages over traditional liquid crystal displays. Firstly, it can show a variety of colours and graphic images, since graphic shapes and alphanumeric characters can be custom patterned onto the polyester film. These patterns then become alternately opaque or transparent as voltage is turned off or on, and coloured dyes can be added for greater contrast and visual diversity. Secondly, the liquid crystal film is only 0.010 to 0.015 thick and can be cut to virtually any size and shape. This means that displays can be lighter and thinner than previously, and they can also be at an angle rather than being flat. When these features become part of a membrane switch panel assembly, designers will have at their fingertips keys that flash and change colour, as well as a variety of graphic images. Any new product requiring an information display will thus be able to benefit from the new type of display. All of which leaves Screen Print Technology contemplating the multi-million pound business that it believes will shortly come its way. The company is currently investing UKP500,000 in the revolutionary NCAP product, which will have its first public airing at the British Electronics Week Exhibition at London’s Olympia on Tuesday, Wednesday and Thursday next week.
