Inorganic alignment layers using noncontact method for liquid crystal displays

Inorganic alignment materials were deposited on indium-tin-oxide (ITO) glass by reactive sputtering deposition. After deposition, inorganic alignment materials such as a-SiO_x and a-SiO_x:H were irradiated using an Ar⁺ ion beam (IB) for liquid crystal (LC) alignment. On the basis of the experimental results, an a-SiO_x film deposited by sputtering does not align LCs regardless of IB treatment, but an a-SiO _x:H film treated with varying IB energies, IB incident angles, IB doses, and IB irradiation times has excellent alignment properties and electro optical properties, the same as polyimide (PI). We investigated period of the stability of an inorganic alignment layer treated with IB after a long time. From the experimental results, the inorganic alignment layer irradiated with an IB does not experience degradation of its electro optical properties. These results imply that an inorganic alignment layer irradiated with IB can be adopted as an LC alignment layer instead of rubbed PI and that hydrogen plays an important role in LC alignment due to the difference in alignment properties between a-SiO_x films and a-SiO_x:H films.