We have investigated the electrooptical characteristics and viewing-angle properties of liquid crystal (LC) display devices referred as the electrically induced hybrid twisted nematic (EHTN) LC display devices, in which LC molecular orientation effects in inhomogeneous electric fields induced by grating electrode structures are utilized. The properties of EHTN display devices are studied in a measurement setup with an actual backlight unit as a light source. We have demonstrated that these devices have high contrast ratios, wide and symmetrical viewing-angle properties, specially in the direction perpendicular to the grating direction. Since there are diffraction effects from the gratings of periodic LC molecular orientations, we discuss the influence of the diffraction effects on viewing-angle properties by evaluating two kinds of EHTN LC cells fabricated by Al metal thin film (obscure) and ITO (transparent) grating electrode structures, show the possibility of realizing good viewing- angle properties by appropriate grating structures.
By determining Stokes' parameters of light diffracted from a nematic liquid crystal grating fabricated with a grating electrode structure, polarization modulation properties of this LC grating are characterized. The electrically controllable polarization modulations of its diffracted light are demonstrated as well as its diffraction light intensity modulations. A unique property of symmetrical diffraction light intensities but antisymmetrical polarization states in corresponding negative and positive diffraction orders is shown.