Intra-cell ionic properties of twisted nematic liquid crystal cells.
- Resource Type
- Article
- Authors
- Chen, Po-An; Yang, Kei-Hsiung
- Source
- Liquid Crystals. Jan2019, Vol. 46 Issue 2, p203-209. 7p.
- Subject
- *NEMATIC liquid crystals
*POLYIMIDES
*INTERFEROMETRY
*ELECTRIC potential
*THIN film transistors
- Language
- ISSN
- 0267-8292
Under 1-kHz and low-frequency driving, we report our investigation of intra-cell ionic properties of two twisted nematic (TN) liquid crystal (LC) cells made of same LC mixture but different polyimide (PI) materials for LC alignments. A heterodyne interferometry system was used to measure the phase retardations of the TN cells versus applied voltages at 1 kHz. We also measured the phase retardations and currents of the TN cells versus time by applying a mid-grayscale voltage of 1.3 V at 0.1 Hz to the cells. Related to the above-measured data, we have developed equations to characterise the field-driven transports of mobile charge carriers within the PI films independently from that within the LC medium of same TN cell to obtain time-dependent in-cell voltages of mobile charge carries across the LC mixture and across two PI-alignment films, respectively. Our experimental methods can be used to optimise LC mixtures and PI materials for low-refresh-rate thin-film-transistor-driven liquid crystal displays (LCDs) for low power and provide bases for further investigations on mobile-charge-carrier generation and transport within thin in-cell PI-alignment films as well as within the LC mixture of same LC cell. [ABSTRACT FROM AUTHOR]