Polymer Distribution Control of Polymer-Dispersed Liquid Crystals by Uni-Directionally Diffused UV Irradiation Process

Yuya HORII; Yosei SHIBATA; Takahiro ISHINABE; Hideo FUJIKAKE

doi:10.1587/transele.E101.C.857

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Polymer Distribution Control of Polymer-Dispersed Liquid Crystals by Uni-Directionally Diffused UV Irradiation Process

Yuya HORII, Yosei SHIBATA, Takahiro ISHINABE, Hideo FUJIKAKE

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Recently, a control technique of light distribution pattern has become important to improve the functionality and the light utilization efficiency of electronic displays, illumination devices and so on. As a light control technique, polymer-dispersed liquid crystals (PDLCs) have been commonly used so far. However, a precise control of the light diffusion distribution of conventional PDLC has been difficult due to the random polymer network structure, which results in the low light utilization efficiency. On the other hand, reverse-mode PDLCs with homogeneously aligned molecules can anisotropically diffuse light. The reverse-mode PDLC, however, has polarization dependency in the haze value due to homogeneously aligned molecules, which also results in the low light utilization efficiency. Therefore, it is necessary to establish the optimization method of light diffusion distribution without the molecules alignment treatment, and we have proposed a novel PDLC with structure-controlled polymer network which was fabricated by the irradiation with uni-directionally diffused UV light. In this paper, we investigated the effect of the process temperature during UV irradiation on the internal structure and light diffusion distribution of the proposed PDLC. As a result, in case that the mixture during UV irradiation was in isotropic phase, we clarified that the structure-controlled PDLCs with alternating striped LCs/polymer pattern could be obtained because the mixture was sufficiently irradiated with uni-directionally diffused UV light. For the high haze, this structure-controlled PDLC should be fabricated as low temperature as possible with maintaining the mixture in isotropic phase so that the mixture was not a nano-scaled molecular mixing state. Also, this PDLC had no polarization dependency in the haze value and could electrically switch the light distribution pattern between anisotropic light diffusion and light transmission. From the above results, we concluded that the proposed PDLC could precisely control the light diffusion distribution, and realize the high light utilization efficiency.

Publication: IEICE TRANSACTIONS on Electronics Vol.E101-C No.11 pp.857-862

Publication Date: 2018/11/01

Publicized

Online ISSN: 1745-1353

DOI: 10.1587/transele.E101.C.857

Type of Manuscript: Special Section INVITED PAPER (Special Section on Electronic Displays)

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Authors

Yuya HORII
  Tohoku University
Yosei SHIBATA
  Tohoku University
Takahiro ISHINABE
  Tohoku University
Hideo FUJIKAKE
  Tohoku University

Keyword

light control, polymer-dispersed liquid crystal, polymer network structure, UV curing

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Yuya HORII, Yosei SHIBATA, Takahiro ISHINABE, Hideo FUJIKAKE, "Polymer Distribution Control of Polymer-Dispersed Liquid Crystals by Uni-Directionally Diffused UV Irradiation Process" in IEICE TRANSACTIONS on Electronics, vol. E101-C, no. 11, pp. 857-862, November 2018, doi: 10.1587/transele.E101.C.857.
Abstract: Recently, a control technique of light distribution pattern has become important to improve the functionality and the light utilization efficiency of electronic displays, illumination devices and so on. As a light control technique, polymer-dispersed liquid crystals (PDLCs) have been commonly used so far. However, a precise control of the light diffusion distribution of conventional PDLC has been difficult due to the random polymer network structure, which results in the low light utilization efficiency. On the other hand, reverse-mode PDLCs with homogeneously aligned molecules can anisotropically diffuse light. The reverse-mode PDLC, however, has polarization dependency in the haze value due to homogeneously aligned molecules, which also results in the low light utilization efficiency. Therefore, it is necessary to establish the optimization method of light diffusion distribution without the molecules alignment treatment, and we have proposed a novel PDLC with structure-controlled polymer network which was fabricated by the irradiation with uni-directionally diffused UV light. In this paper, we investigated the effect of the process temperature during UV irradiation on the internal structure and light diffusion distribution of the proposed PDLC. As a result, in case that the mixture during UV irradiation was in isotropic phase, we clarified that the structure-controlled PDLCs with alternating striped LCs/polymer pattern could be obtained because the mixture was sufficiently irradiated with uni-directionally diffused UV light. For the high haze, this structure-controlled PDLC should be fabricated as low temperature as possible with maintaining the mixture in isotropic phase so that the mixture was not a nano-scaled molecular mixing state. Also, this PDLC had no polarization dependency in the haze value and could electrically switch the light distribution pattern between anisotropic light diffusion and light transmission. From the above results, we concluded that the proposed PDLC could precisely control the light diffusion distribution, and realize the high light utilization efficiency.
URL: https://global.ieice.org/en_transactions/electronics/10.1587/transele.E101.C.857/_p

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@ARTICLE{e101-c_11_857,
author={Yuya HORII, Yosei SHIBATA, Takahiro ISHINABE, Hideo FUJIKAKE, },
journal={IEICE TRANSACTIONS on Electronics},
title={Polymer Distribution Control of Polymer-Dispersed Liquid Crystals by Uni-Directionally Diffused UV Irradiation Process},
year={2018},
volume={E101-C},
number={11},
pages={857-862},
abstract={Recently, a control technique of light distribution pattern has become important to improve the functionality and the light utilization efficiency of electronic displays, illumination devices and so on. As a light control technique, polymer-dispersed liquid crystals (PDLCs) have been commonly used so far. However, a precise control of the light diffusion distribution of conventional PDLC has been difficult due to the random polymer network structure, which results in the low light utilization efficiency. On the other hand, reverse-mode PDLCs with homogeneously aligned molecules can anisotropically diffuse light. The reverse-mode PDLC, however, has polarization dependency in the haze value due to homogeneously aligned molecules, which also results in the low light utilization efficiency. Therefore, it is necessary to establish the optimization method of light diffusion distribution without the molecules alignment treatment, and we have proposed a novel PDLC with structure-controlled polymer network which was fabricated by the irradiation with uni-directionally diffused UV light. In this paper, we investigated the effect of the process temperature during UV irradiation on the internal structure and light diffusion distribution of the proposed PDLC. As a result, in case that the mixture during UV irradiation was in isotropic phase, we clarified that the structure-controlled PDLCs with alternating striped LCs/polymer pattern could be obtained because the mixture was sufficiently irradiated with uni-directionally diffused UV light. For the high haze, this structure-controlled PDLC should be fabricated as low temperature as possible with maintaining the mixture in isotropic phase so that the mixture was not a nano-scaled molecular mixing state. Also, this PDLC had no polarization dependency in the haze value and could electrically switch the light distribution pattern between anisotropic light diffusion and light transmission. From the above results, we concluded that the proposed PDLC could precisely control the light diffusion distribution, and realize the high light utilization efficiency.},
keywords={},
doi={10.1587/transele.E101.C.857},
ISSN={1745-1353},
month={November},}

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TY - JOUR
TI - Polymer Distribution Control of Polymer-Dispersed Liquid Crystals by Uni-Directionally Diffused UV Irradiation Process
T2 - IEICE TRANSACTIONS on Electronics
SP - 857
EP - 862
AU - Yuya HORII
AU - Yosei SHIBATA
AU - Takahiro ISHINABE
AU - Hideo FUJIKAKE
PY - 2018
DO - 10.1587/transele.E101.C.857
JO - IEICE TRANSACTIONS on Electronics
SN - 1745-1353
VL - E101-C
IS - 11
JA - IEICE TRANSACTIONS on Electronics
Y1 - November 2018
AB - Recently, a control technique of light distribution pattern has become important to improve the functionality and the light utilization efficiency of electronic displays, illumination devices and so on. As a light control technique, polymer-dispersed liquid crystals (PDLCs) have been commonly used so far. However, a precise control of the light diffusion distribution of conventional PDLC has been difficult due to the random polymer network structure, which results in the low light utilization efficiency. On the other hand, reverse-mode PDLCs with homogeneously aligned molecules can anisotropically diffuse light. The reverse-mode PDLC, however, has polarization dependency in the haze value due to homogeneously aligned molecules, which also results in the low light utilization efficiency. Therefore, it is necessary to establish the optimization method of light diffusion distribution without the molecules alignment treatment, and we have proposed a novel PDLC with structure-controlled polymer network which was fabricated by the irradiation with uni-directionally diffused UV light. In this paper, we investigated the effect of the process temperature during UV irradiation on the internal structure and light diffusion distribution of the proposed PDLC. As a result, in case that the mixture during UV irradiation was in isotropic phase, we clarified that the structure-controlled PDLCs with alternating striped LCs/polymer pattern could be obtained because the mixture was sufficiently irradiated with uni-directionally diffused UV light. For the high haze, this structure-controlled PDLC should be fabricated as low temperature as possible with maintaining the mixture in isotropic phase so that the mixture was not a nano-scaled molecular mixing state. Also, this PDLC had no polarization dependency in the haze value and could electrically switch the light distribution pattern between anisotropic light diffusion and light transmission. From the above results, we concluded that the proposed PDLC could precisely control the light diffusion distribution, and realize the high light utilization efficiency.
ER -