| Abstract: | Abstract— A new optical method for determining the pretilt angle ψ0, particularly on twisted‐nematic (TN) liquid‐crystal (LC) cells, is proposed. ψ0 was rapidly determined with good reproducibility on a TN‐LC cell by using a rotating analyzer optical system, a twist angle Φ, the azimuth of the director at a substrate, ϕ0, and the retardation Δnd as known values. The thickness d was also determined simultaneously with ψ0. ψ0 and d were determined within minutes. ψ0 was previously determined to be in the range of 0.1° with a standard deviation of 0.01°; this was obtained by repeating the measurement 50 times. The principle behind the determination and the experimental set up are described in detail. |
