ACCURATE DETERMINATION AND MEASUREMENT ERROR OF PRETILT ANGLE IN LIQUID-CRYSTAL CELL

To measure the pretilt angle in a liquid crystal cell, the crystal rotation method is commonly used because it is very precise and measurements can be obtained rapidly. However when a liquid crystal cell with insufficient uniformity of the cell gap is used, a significant error occurs due to a shift in the measurement point. This shift is caused by refraction of the glass plate during rotation of the cell. In this paper, we estimate the magnitude of this error theoretically and propose a new method by which an accurate value can be obtained even if the cell gap is not uniform.