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Proceedings Paper

Liquid crystal devices based on photoalignment and photopatterning materials
Author(s): Vladimir Chigrinov
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Paper Abstract

Liquid crystal (LC) display and photonics devices based on photo-alignment and photo-patterning LC cells are developed. A fast switchable grating based on ferroelectric liquid crystals and orthogonal planar alignment by means of photo alignments. Both 1D and 2D gratings have been constructed. The proposed diffracting element provides fast response time of around 20 μs, contrast of 7000:1 and high diffraction efficiency, at the electric field of 6V/μm. A switchable LC Fresnel zone lens was also developed with the efficiency of ~42% that can be further improved, and the switching time for the 3 μm thick cell is ~6.7 ms which is relatively fast in comparison of existing devices. Thus, because of the photoalignment technology the fabrication of Fresnel lens became considerably simpler than others. A thin high spatial resolution, photo-patterned micropolarizer array for complementary metal–oxide–semiconductor (CMOS) image sensors was implemented for the complete optical visualization of so called “invisible” objects, which are completely transparent (reflective) and colorless. Four Stokes parameters, which fully characterized the reflected light beam can be simultaneously detected using the array of photo-patterned polarizers on CMOS sensor plate. The cheap, high resolution photo-patterned LC matrix sensor was developed to be able successfully compete with the expensive and low reliable wire grid polarizer patterned arrays currently used for the purpose.

Paper Details

Date Published: 19 February 2014
PDF: 10 pages
Proc. SPIE 9004, Emerging Liquid Crystal Technologies IX, 90040A (19 February 2014); doi: 10.1117/12.2036555
Show Author Affiliations
Vladimir Chigrinov, Hong Kong Univ. of Science and Technology (Hong Kong, China)

Published in SPIE Proceedings Vol. 9004:
Emerging Liquid Crystal Technologies IX
Liang-Chy Chien; Antonio M. Figueiredo Neto; Kristiaan Neyts; Masanori Ozaki, Editor(s)

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