• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.627-628
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• 2008

We have studied the optical performance of flexible polymer network liquid crystal (PNLC) films at various bending states. Different measurement setups, wide and narrow opening angles of detector, were used to collect scatting light of PNLC films. The optical and dynamic properties of bent PNLC implied the change of LC domains.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08a
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• pp.73-75
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• 2007

Micro-cell LC film and polymer network liquid crystal (PNLC) film by using continuous compatible process have been developed . A high-contrast micro-cell LC film has a strong potential as a high-performance flexible device. PNLC film has the low driving voltage. Both films show the characteristics of lightness, thinness and mechanical stability.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.10
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• pp.885-890
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• 1998

The electro-optical properties of polymer dispersed liquid crystals (PDLCs) depend on dispersion structures and nematic alignment which can be controlled by taking proper liquid crystal/polymer mixtures and process conditions. To achieve excellent electro-optical properties such as low driving voltage, good contrast ratio and negligible hysteresis, we have developed optimization procedure. Under the optimized conditions, PDLC of low threshold voltage less than 3.1 V, high contrast ratio more than 150 and negligible hysteresis were obtained.

• Applied Chemistry for Engineering
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• v.9 no.4
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• pp.579-584
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• 1998

Polymer dispersed liquid crystal(PDLC) composite films were made by polymerization induced phase separation method using UV-curing to investigate the effect of fabrication conditions, such as photoinitiator concentration, film thickness, polymerization temperature, and electric field during polymerization, etc., on the electro-optic properties. As the amount of photoinitiator increased, the driving voltage of PDLC device increased due to the increase of small-size liquid crystal phases. This was considered as the results from the increased interfacial area between liquid crystal (LC) and polymer matrix, since LC molecules at the interfacial regions were relatively difficult to response for the applied electric field. When the higher molecular weight oligomer (PTDA-1000) was used as matrix, the initial transmittance was observed to be relatively higher than that for the lower molecular weight oligomer (PTDA-250). Saturation transmittance for PTDA-1000 was observed at relatively lower voltage than that for PTDA-250, of which transmittance was not saturated even at 60 V. As polymerization temperature increased, the initial transmittance of resulting PDLC film increased due to the larger LC droplets formation and the more matched refractive index between LC and matrix than those cases for the lower polymerization temperature. Though driving voltage decreased for the thinner film, it was considered that optimum thickness of the film should be maintained to get some practical contrast, which is the ratio of off- and on-state transmittance. Furthermore, electro-optic properties such as initial transmittance, driving voltage, and response time were observed to be considerably affected by application of external field during polymerization.