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Optical Engineering

Liquid crystal optically variable device with continuously distributed colors
Author(s): Jiwei Zhou; Guangming Ke; Bin Wang; Haibo Chen; Geng Chen; Ruixing Li
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Paper Abstract

A liquid crystal optically variable device (LCOVD) was fabricated by linearly polarized photoalignment technique. The device is composed of a nematic liquid crystal layer on the polyethylene terephthalate (PET) substrate and two parallel polarizers. By continuously changing the polarization direction during photoalignment, the optical axes of the liquid crystal can be variably aligned. We measured the colors and transmission spectra of the LCOVD at different observing angles. The results indicate that the colors of the device distribute continuously. The colors shift to others with the changing of the observing positions, and such color shift phenomenon depends not only on the observing inclination angle but also the azimuth angle. Furthermore, a calculation method based on the Jones matrix for simulating the performance of the LCOVD was established. The theoretical results show good agreement with the experiment. Because of the distinctive optical features, one highly significant application of the LCOVD may be its use for improving document security.

Paper Details

Date Published: 1 August 2011
PDF: 7 pages
Opt. Eng. 50(8) 081203 doi: 10.1117/1.3565042
Published in: Optical Engineering Volume 50, Issue 8
Show Author Affiliations
Jiwei Zhou, BeiHang Univ. (China)
Guangming Ke, Security Printing Institute of People's Bank of China (China)
Bin Wang, Security Printing Institute of People's Bank of China (China)
Haibo Chen, Security Printing Institute of People's Bank of China (China)
Geng Chen, Security Printing Institute of People's Bank of China (China)
Ruixing Li, BeiHang Univ. (China)


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