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http://dx.doi.org/10.3807/JOSK.2014.18.6.753

Enhanced Adhesion and Transmittance Uniformity in Laminated Polymer-Dispersed Liquid Crystal Films  

Yoo, Seong-Hyeon (Department of Sensor and Display Engineering, Kyungpook National University)
Park, Min-Kyu (School of Electronics Engineering, Kyungpook National University)
Park, Ji-Sub (School of Electronics Engineering, Kyungpook National University)
Kim, Hak-Rin (Department of Sensor and Display Engineering, Kyungpook National University)
Publication Information
Journal of the Optical Society of Korea / v.18, no.6, 2014 , pp. 753-761 More about this Journal
Abstract
We propose a two-step UV irradiation procedure to fabricate polymer-dispersed liquid crystal (PDLC) films by lamination. During the first UV treatment, before lamination, the UV-curable monomers coated on one film substrate are solidified through photo-polymerization as the phase separation between the liquid crystals and the monomers. Introducing an adhesion-enhancement layer on the other plastic substrate and controlling the UV irradiation conditions ensure that UV-induced cross-linkable functional groups remain on the surfaces of the photo-polymerized layers. Thereby, the adhesion stability between the top and bottom films is much improved during a second (post-lamination) UV treatment by further UV-induced cross-linking at the interface. Because the adhesion-enhancement and PDLC layers prepared by the bar-coating process are solidified before lamination, the PDLC droplet distribution and the cell gap between the two plastic substrates remain uniform under the lamination pressure. This ensures that the voltage-controlled light transmittance is uniform across the entire sample.
Keywords
Liquid crystals; Polymer-dispersed liquid crystals; Flexible displays; Lamination process; Phase separation;
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