THE IN-PLANE SWITCHING OF HOMOGENEOUSLY ALIGNED NEMATIC LIQUID CRYSTALS

We have investigated the electro-optical effects and physical switching principle of homogeneously aligned nematic liquid crystals when applying an in-plane electric field with interdigital electrodes. By using the in-plane switching (IPS) of the liquid crystals which is achieved by the in-plane electric field, the viewing angle characteristics of the electro-optical effects were confirmed to be far superior to those of the conventional twisted nematic mode in which the electric field is applied along the direction perpendicular to the substrates. The non-reversal region of grey scales was extremely wide in which a high contrast ratio was kept, even along quite an oblique direction in the IPS mode. In order to clarify the switching principle of the liquid crystals in the IPS mode, a simplified expression describing the threshold behaviour of the device was derived with the assumption that a uniform in-plane electric field was applied along a direction perpendicular to the director and parallel to the homo...