Simultaneous Determination of Large Pretilt Angles and Cell Gap in Liquid Crystal Displays

Abstract

Abstract-A method for the measurement of arbitrary pretilt angles in liquid crystal displays is proposed and demonstrated. The cell gap can also be determined accurately in the same experiment as well. This method makes use of a photo-elastic modulator and is capable of measuring pretilt angles from 0 to 90 precisely.

Anisotropic thin films formation rate on PEDOT : PSS layer with high azimuthal anchoring

“…Pretilt angle was measured by crystal rotation method . Azimuthal anchoring energy increases with the raise of rubbing length.…”

Ultraviolet-light-treated polyimide alignment layers for polarization-independent liquid crystal Fresnel lenses

“…Then the surface of the PI film was mechanically buffed using a nylon cloth. The surface energy of the PI film was determined by measuring the contact angle of distilled water on the film according to the Girifalco-GoodFowkes-Young model [19]. To determine the pretilt angle and the polar anchoring energy (PAE) of LC molecules on UV-treated PI alignment layers, anti-parallel LC test cells were fabricated with a cell gap of 6.7 µm and were capillary filled with positive dielectric anisotropic or negative dielectric anisotropic LC molecules (E7 and MLC 6882, Merck).…”

Controlling the Alignment of Polyimide for Liquid Crystal Devices

“…However, it is difficult to precisely determine the symmetry point of transmission in the rotation-angle-dependent transmission curve for a LC device with a thin cell gap or a medium pretilt angle. A modified crystal rotation method combined with the common path heterodyne interferometer was used in this work (Hwang & Hsu, 2006;Li et al, 2008). Due to the designed common-path configuration, the phase retardation of the LC cell can be accurately determined in terms of the phase difference of the optical heterodyne signal.…”