Improvement in device performance from a mixture of a liquid crystal and photosensitive acrylic prepolymer with the photoinduced vertical alignment method |
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Authors: | Czung-Yu Ho Fa-Hsin Lin Yu-Tai Tao Jiunn-Yih Lee |
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Affiliation: | 1.Institute of Chemistry, Academia Sinica, Taipei 115, Taiwan;2.Department of Materials Science and Engineering, National Taiwan University of Science and Technology, Taipei 106, Taiwan |
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Abstract: | In a multicomponent nematic liquid crystal (NLC) mixture of a liquid crystal (negative-type NLC) and a photosensitive acrylic prepolymer, photopolymerization upon UV irradiation induces the separation of the LC and photosensitive acrylic prepolymer layers, thereby leading to a vertical arrangement of LC molecules. In this study, we propose a simple vertical alignment method for LC molecules, by adding a chiral smectic A (SmA∗) liquid crystal having homeotropic texture characteristics to an NLC mixture solution. Measurements of electro-optical properties revealed that the addition of the SmA∗ LC not only strengthened the anchoring force of the copolymer alignment film surface, but also significantly enhanced the contrast ratio (∼73%), response time and grayscale switching performance of the device. |
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Keywords: | liquid crystal photosensitive prepolymer vertical arrangement effect homeotropic texture electro-optical properties grayscale switching |
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