Browsing by Author "Hsu, Hsu-Kuan"

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A bistable polarizer-free electro-optical switch using a droplet manipulation on a liquid crystal and polymer composite film
(2010-05-10)
Lin, Yi-Hsin
;
Li, Jiong-Kuan
;
Chu, Ting-Yu
;
Hsu, Hsu-Kuan
;
光電工程學系
A bistable, polarizer-free, and reflective electro-optical switch based on a droplet manipulation on a liquid crystal and polymer composite film (LCPCF) is demonstrated. A color droplet on LCPCF can be manipulated by a wettability gradient owning to the distribution of LC directors anchored among the polymer grains on LCPCF. The contrast ratio is around 8: 1 in a reflective mode. The potential applications of droplet manipulation are electronic papers and reflective displays. (C)2010 Optical Society of America
A Reflective Polarizer-free Display Using a Droplet Manipulation on a Liquid Crystal and Polymer Composite Film
(2009)
Lin, Yi-Hsin
;
Lin, Hung-Chun
;
Li, Jiong-Kuan
;
Hsu, Hsu-Kuan
;
Li, Wang-Yang
A polarizer-free display using a droplet manipulation on a liquid crystal and polymer composite film (LCPCF) is demonstrated. Because of the electrically tunable orientation of the liquid crystal directors anchored among the polymer grains, the wettability of the LCPCF changes with an applied in-planed electric field. As a result, we can realize a reflective polarizer-free display when the colored droplet on the top of the LCPCF is manipulated by an inhomogeneous electric field. The contrast ratio is around 9:1 and the response time is around 900 ms.
A reflective polarizer-free electro-optical switch using dye-doped polymer-stabilized blue phase liquid crystals
(2011-01-31)
Lin, Yi-Hsin
;
Chen, Hung-Shan
;
Chiang, Tsung-Han
;
Wu, Chun-Hung
;
Hsu, Hsu-Kuan
We demonstrate a reflective polarizer-free electro-optical switch using dye-doped polymer-stabilized blue phase liquid crystals (DDPSBP-LC). At the voltage-off state, the dye molecules and liquid crystals form the structure of the double twist cylinders. As a result, the DDPSBP-LC is in dark state due to the combination of Bragg reflection and light absorption. At the voltage-on state, the blue phase structure is unwound locally. The DDPSBP-LC is then in bright state because of the small light absorption only. The applications of such a switch are shutter glass of 3D displays, and electronic papers. (C) 2011 Optical Society of America
Hysteresis-free polymer-stabilized blue phase liquid crystals using thermal recycles
(1970-01-01)
Chen, Hung-Shan
;
Lin, Yi-Hsin
;
Wu, Chun-Hung
;
Chen, Michael
;
Hsu, Hsu-Kuan
"We demonstrate a hysteresis-free polymer-stabilized blue phase liquid crystals (PSBP-LCs) using thermal recycles by means of enlarging the domain size of PSBP-LC and improving the uniformity of the crystal orientations of PSBP-LC. The crystal growth of PSBP-LCs bases on a competition between the heterogeneous nucleation and the homogeneous nucleation is also demonstrated and discussed. This study opens a new window for understanding the hysteresis of the PSBP-LC and assisting in designing many PSBP-LC-based photonic devices, such as displays, electro-optical switches, and electrically tunable focusing LC lenses. (C)2012 Optical Society of America"
Measuring electric-field-induced birefringence in polymer stabilized blue-phase liquid crystals based on phase shift measurements
(2011-05-15)
Lin, Yi-Hsin
;
Chen, Hung-Shan
;
Wu, Chun-Hung
;
Hsu, Hsu-Kuan
;
光電工程學系
A simple optical method to measure the electric-field-induced birefringence and Kerr constant of polymer-stabilized blue-phase liquid crystals (PSBP-LC) is demonstrated. By measuring the phase shift of PSBP-LC and the averaged refractive index of PSBP-LC at the voltage-off state, the ordinary refractive index and extraordinary refractive index of PSBP-LC as function of applied voltage can be obtained experimentally. As a result, the electric-field-induced birefringence and Kerr constant can be determined as well. The method we proposed can help in designing PSBP-LC-based photonic devices. (C) 2011 American Institute of Physics. [doi:10.1063/1.3583572]
Polarizer-free and fast response microlens arrays using polymer-stabilized blue phase liquid crystals
(2010-03-15)
Lin, Yi-Hsin
;
Chen, Hung-Shan
;
Lin, Hung-Chun
;
Tsou, Yu-Shih
;
Hsu, Hsu-Kuan
We demonstrate polarizer-free and fast response microlens arrays based on optical phase modulation of polymer-stabilized blue phase liquid crystal (PSBP-LC). Polarization-independent optical phase shift is because the propagation of an incident light is along the optic axis of PSBP-LC, and birefringence of PSBP-LC induced by Kerr effect results in electrically tunable optical phase shift. The measured optical phase shift of a PSBP-LC phase modulation is around pi radian at 150 V(rms) for the cell gap of 7 mu. The response time is about 3 ms. The focal length is around 13.1 cm at 100 V(rms).
The Dynamics of Human Sperm Droplets on a Liquid Crystal and Polymer Composite Film
(2010-01-01)
Lu, Farn
;
Lin, Yi-Hsin
;
Tsai, Wan-Chen
;
Li, Jiong-Juan
;
Chu, Ting-Yu
A switchable surface using a liquid crystal and polymer composite film (LCPCF) based on phase separation between liquid crystals (LC) and polymers after photopolymerization is developed recently. The wettability of LCPCF is electrically tunable because of the orientation of liquid crystal directors anchored among the polymer grains under an in-planed electric field. A water droplet on the top of LCPCF can be manipulated under an inhomogeneous electric field on the LCPCF owning to the wettability gradient. The dynamics of a droplet of human sperms on the LCPCF is demonstrated as well. Three motions of sperm droplets are observed: the droplet collapse and the droplet stretch,. We found that the dynamics, concentrations, and activities of spermatozoa, affect the motions of a sperm droplet. The potential applications of LCPCF are polarizer-free displays, liquid lenses, and the microfluidic device in assisted reproductive technology (ART)
Variable liquid crystal pretilt angles generated by photoalignment in homeotropically aligned azo dye-doped liquid crystals
(2009-10-19)
Fuh, Andy Ying-Guey
;
Liu, Cheng-Kai
;
Cheng, Ko-Ting
;
Ting, Chi-Lung
;
Chen, Che-Chang
This letter demonstrates the feasibility of producing variable liquid crystal (LC) pretilt angles using light-induced ripple structures (LIRSs) in homeotropically aligned azo dye-doped liquid crystals (ADDLCs). Illuminating homeotropically aligned ADDLCs with a linearly polarized light for a suitable period yields the LIRSs which provide LCs an anisotropic homogeneous anchoring force. Experimentally, the effective alignment force produced by the homeotropic alignment layer and the LIRSs determines the LC pretilt angle (24 degrees to 63.5 degrees), defined from the normal to the substrate. A no-bias pi cell for liquid crystal displays is demonstrated using this approach. (C) 2009 American Institute of Physics. [doi: 10.1063/1.3253413]