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Title: The new electro-optic effects for chiral nematic liquid crystals
Author: Chen, J.
Awarding Body: University of Cambridge
Current Institution: University of Cambridge
Date of Award: 2009
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This thesis studies several electro-optic effects of chiral nematic liquid crystals (N*LCs) for applications in displays and telecommunications. During these studies, an unusual coloured scattering effect of N*LC was observed. Further developing the experiment technique and the use of LC compounds, the reversible colour switching of a polymer stabilised N*LC at an oblique angle has also been demonstrated. In addition, by controlling the processing at different stages we are able to form a new switching mode 10 times faster in response time for a reflective display compared to normal switching modes in N*LC. The flexoelectro-optic effect of the N*LC provides fast switching and when it is aligned in the ULH texture; An in-plane switching of the optic axis that is linear to applied electric field across the sample. These remarkable characteristics give a grey scale capability and provided a potential application in amplitude or phase modulation. In this work, an investigation of the flexoelectro-optic effect of the N*LC in the ULH texture was carried out by examining the LC compounds and a novel LC material with a large tilt angle. Result show the relationship of the pitch length of the N*LC helix, a weak polymer network and an applied frequency to the flexoelectro-optic effect of the N*LC in the ULH texture. In addition, we also show the feasibility of using ferroelectric nanoparticles to optimise the flexoelectro-optic effect. Both a significant improvement in tilt angle and response time was observed.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available