Gradient pretilt angle alignment materials with different photosensitivity for tunable polarization‐independent self‐aligned liquid crystal lens

• Published in: Journal of the Society for Information Display 2021-11, Vol.29 (11), p.825-832
• Main Authors: Bezruchenko, Veronika S., Muravsky, Alexander A., Murauski, Anatoli A., Stankevich, Alexander I., Mahilny, Uladzimir V.
• Format: Article
• Language: English
• Subjects: Alignment; Benzaldehyde; Exposure; gradient alignment materials; Lenses; Liquid crystals; Nematic crystals; Photosensitivity; Polarization; polarization‐independent LC lens; Refractivity
• ISSN: 1071-0922; 1938-3657
• DOI: 10.1002/jsid.990

Alignment of benzaldehyde materials with different photosensitivity thresholds, capable of changing the pretilt angles of nematic liquid crystal (LC) from 90° to 0° in a controlled manner under UV‐B exposure, has been developed. Inhomogeneous exposure of uniform rubbed alignment layers allows the formation of a refractive index gradient inside the LC cell. The concept of tunable polarization‐independent self‐aligned LC lens based on gradient pretilt angle alignment materials with different photosensitivity is demonstrated. Self‐alignment of two polarization‐dependent sub‐lens is achieved due to a single exposure act of two alignment layers, which are located on the same piece of glass on both sides, forming one common optical axis for a polarization‐independent LC lens. The sub‐lens cells have uniform cell gap and are independently controlled using low‐voltage driving. Devices based on gradient benzaldehyde alignment materials can be used in many modern optical and photonic devices. The concept of tunable self‐aligned polarization‐independent LC lens (PILCL) based on pretilt angle alignment materials with different photosensitivity is demonstrated. Self‐alignment is realized through simultaneous exposure of alignment layers with different photosensitivity, with perpendicular crossing of the azimuthal alignment rubbing direction, coated on both sides of the middle double‐sided ITO glass substrate. The sample of PILCL was made and characterized.