The Zenithal Bistable Display: A Grating Aligned Bistable Nematic Liquid Crystal Device

The flexibility, durability, and lightweight offered by plastic displays have not been accomplished commercially, despite years of research. However, significant commercial progress of a bistable nematic liquid crystal display (LCD) did not occur until the invention of the Zenithal Bistable Display (ZBD) in 1995. Thermotropic liquid crystal behavior occurs in rigid, anisotropic organic molecules, with the degree of order being related to the temperature of the material. Compared with other LCD alignment surfaces, either rubbed or photoaligned polymers, the ZBD surface requires considerable engineering to achieve consistent device operation. Surface bistability in ZBD is realised using a surface grating as one of the liquid crystal alignment layers. Although it is possible to create a scattering mode ZBD LCD, this technology is usually configured to operate by modulating polarized light. As well as a two-polariser fully reflective LCD mode, the ZBD technology can be deployed in other configurations, which can have merits for particular applications.