Browsing by Author "Hsu, Hsuan-Tsung"

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Dielectric and Electro-Optical Properties of Polymer-Stabilized-Blue-Phase Cells
(2015-08-13)
Hsu, Hsuan-Tsung
;
Wu, Po-Chang
;
Lee, Wei
;
光電學院
;
影像與生醫光電研究所
Dielectric characterization and voltage holding ratio of blue-phase cells
(2016-09)
Wu, Po-Chang
;
Hsu, Hsuan-Tsung
;
Chen, Hsin-Li
;
Lee, Wei
;
光電學院
The phase behaviors of a blue-phase (BP) liquid crystal in a planar-aligned cell were investigated by means of temperature-dependent dielectric spectroscopy. With auxiliary observations of optical transmission spectra and birefringent textures, we found that the transition temperatures of two adjacent mesophases, including the cholesteric-to-BPI, the BPI-to-BPII, and the BPII-to-isotropic, can clearly be distinguished by the first and second derivatives of the real-part dielectric permittivity function to the temperature at a specific frequency. Furthermore, an attempt to evaluate the device performance of a polymer-stabilized BP, derived from the photopolymerization of two monomers (R1V1257 and TMPTA), was achieved with a new circuital design for the voltage-holding-ratio (VHR) measurement. Preliminary results of the VHRs of samples at 180 Hz and their temperature dependence were obtained accordingly. (C) 2015 Elsevier B.V. All rights reserved.
Dielectric characterization and voltage holding ratio of blue-phase cells
(2016-09-01)
Wu, Po-Chang
;
Hsu, Hsuan-Tsung
;
Chen, Hsin-Li
;
Lee, Wei
;
光電學院
The phase behaviors of a blue-phase (BP) liquid crystal in a planar-aligned cell were investigated by means of temperature-dependent dielectric spectroscopy. With auxiliary observations of optical transmission spectra and birefringent textures, we found that the transition temperatures of two adjacent mesophases, including the cholesteric-to-BPI, the BPI-to-BPII, and the BPII-to-isotropic, can clearly be distinguished by the first and second derivatives of the real-part dielectric permittivity function to the temperature at a specific frequency. Furthermore, an attempt to evaluate the device performance of a polymer-stabilized BP, derived from the photopolymerization of two monomers (R1V1257 and TMPTA), was achieved with a new circuital design for the voltage-holding-ratio (VHR) measurement. Preliminary results of the VHRs of samples at 180 Hz and their temperature dependence were obtained accordingly. (C) 2015 Elsevier B.V. All rights reserved.