Browsing by Author "Wu, Shin-Tson"

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Electrically tunable wettability of liquid crystal/polymer composite films
(2008-10-27)
Lin, Yi-Hsin
;
Ren, Hongwen
;
Wu, Yung-Hsun
;
Wu, Shin-Tson
;
Zhao, Yue
An electrically tunable wettability in a liquid crystal/polymer composite film is demonstrated, in which liquid crystal molecules are anchored among polymer grains. The tunable wettability of the composite films originates from the reorientation of the anchored liquid-crystal molecules, which is switched by an in-plane electric field with squared pulses of voltages. These liquid crystal/polymer composite films with electrically tunable wettability have potential applications in polarizer-free displays, ink-jet printing, microfluidic devices, and lab-on-a-chip. (C) 2008 Optical Society of America
Fringing-Field Effects on High-Resolution Liquid Crystal Microdisplays
(2005-12-01)
Fan-Chiang, Kuan-Hsu
;
Wu, Shin-Tson
;
Chen, Shu-Hsia
;
光電工程學系
;
Department of Photonics
Fringing- field effects on high-resolution liquid crystal microdisplay devices, including the reflection-type liquid-crystal-on-silicon (LCOS) and transmission-type poly-silicon thin-film-transistor liquid crystal displays are simulated by the beam propagation method. The electro-optic performances of six commonly used liquid crystal modes are analyzed by the two-dimensional optical simulator. The vertically aligned (VA) cell exhibits the highest contrast ratio, but its fringing-field effect is severe. A circularly polarized light illuminated LCOS device is presented to eliminate the fringing-field effect of the VA cell. Both simulated and confirming experimental results show that the long-standing problems of poor sharpness, low brightness, and slow transition time of the VA cell can be overcome by using a circularly polarized light.
High figure-of-merit laterally fluorinated biphenyltolane-isothiocyanates
(2007)
Gauza, Sebastian
;
Zhao, Yang
;
Le Cor, Tatiana
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Wu, Shin-Tson
;
Ziolek, Anna
We have designed, synthesized, and evaluated the physical properties of some high birefringence (Delta n) isothiocyanato biphenyl-tolane liquid crystals. These compounds exhibit Delta n similar to 0.48-0.52 at room temperature and wavelength lambda = 633 nm. Laterally substituted short alkyl chains and fluorine atom elinlinate smectic phase and lower the melting temperature. The moderate melting temperature and very high clearing temperature make those compounds attractive for eutectic mixture formulation. A eutectic mixture based on those compounds was formulated and its physical properties evaluated.
In situ observation of fringing-field-induced phase separation in a liquid-crystal-monomer mixture
(2008-03-21)
Ren, Hongwen
;
Wu, Shin-Tson
;
Lin, Yi-Hsin
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光電工程學系
;
Department of Photonics
Fringing-field-induced phase separation dynamics in liquid-crystal-(LC-)monomer mixtures is investigated via a microscope. At a low LC concentration, the fringing field converts the randomly dispersed LC droplets to an ordered droplet array, while at a high LC concentration the fringing field converts the amorphous LC-monomer system to a composite film. Because the LC and monomer are immiscible, the converted morphologies are stable even after the voltage is removed. Using the fringing field-induced phase separation, it is possible to prepare different polymer-dispersed LC morphologies.
Optical system design
(2006-11-16)
Chiang, Kuan-Hsu Fan
;
Zhu, Xinyu
;
Wu, Shin-Tson
;
Chen, Shu-Hsia
This invention discloses an optical system design, which is used in a liquid crystal display apparatus. The optical system design at least comprises a light generation module, a circular polarization module and a liquid crystal light valve, wherein the light generation module is used to generate a light, the circular polarization module is used to modulate the polarization state of the light to a circular polarization state, and the liquid crystal light valve is used to modulate the polarization state of the light, so as to modulate the intensity of the light to show the image. The optical system design is able to solve the problem of fringing-field effects.
Polarizer-free Liquid Crystal Displays
(2008)
Lin, Yi-Hsin
;
Yang, Jhih-Ming
;
Wu, Shin-Tson
;
Liao, Chi-Chang
;
光電工程學系
A reflective polarizer-free liquid crystal display (LCD) using dye-doped LC gels is demonstrated. The main mechanism is to combine dye absorption and polydomain scattering. The potential applications are electronic papers and flexible displays.
Pursuing High Quality Phase-Only Liquid Crystal on Silicon (LCoS) Devices
(2018-11-01)
Chen, Huang-Ming Philip
;
Yang, Jhou-Pu
;
Yen, Hao-Ting
;
Hsu, Zheng-Ning
;
Huang, Yuge
Fine pixel size and high-resolution liquid crystal on silicon (LCoS) backplanes have been developed by various companies and research groups since 1973. The development of LCoS is not only beneficial for full high definition displays but also to spatial light modulation. The high-quality and well-calibrated panels can project computer generated hologram (CGH) designs faithfully for phase-only holography, which can be widely utilized in 2D/3D holographic video projectors and components for optical telecommunications. As a result, we start by summarizing the current status of high-resolution panels, followed by addressing issues related to the driving frequency (i.e., liquid crystal response time and hardware interface). LCoS panel qualities were evaluated based on the following four characteristics: phase linearity control, phase precision, phase stability, and phase accuracy.
Quantum Dots Enhanced Liquid Displays
(2014-12-01)
Luo, Zhenyue
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Xu, Su
;
Gao, Yating
;
Lee, Yun-Han
;
Liu, Yifan
Two types of dielectrophoretic liquid displays with patterned quantum dots (QDs) array for enhancing the color performance are demonstrated. QDs not only provide vivid color (similar to 136% AdobeRGB in CIE1976 color space) but also greatly improve light efficiency by reducing the optical loss from color filters. These polarizer-free liquid displays offer vivid colors, high transmittance, wide viewing angle, and modest response time and contrast ratio. They are promising candidates for E-book and mobile display applications.
Single glass substrate liquid crystal device using electric field-enforced phase separation and photoinduced polymerization
(2007-05-07)
Ren, Hongwen
;
Wu, Shin-Tson
;
Lin, Yi-Hsin
;
光電工程學系
;
Department of Photonics
An in-plane switching liquid crystal (LC) cell using a glass substrate and a photoinduced polymer layer is demonstrated. The fabrication process is based on the electrodynamics of dielectric fluids. When the fringing field is present, the LC molecules tend to aggregate in the strong electric field regions while the monomers diffuse to the weak field regions. After photopolymerization, the LC molecules are confined by a thin polymer layer and polymer walls which define the cell gap. This approach enables single-substrate large panel display devices to be fabricated. (C) 2007 American Institute of Physics.
Smart Transflective Display Integrated with PDLC and OPV-embedded-OLED
(2009-01-01)
Lee, Jiun-Haw
;
Chiu, Tien-Lung
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Chuang, Kai-Hsiang
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Lin, Yi-Hsin
;
Wu, Shin-Tson
We demonstrated a hybrid transfective device by vertically integrating a PDLC and an OLED with OPV as the reflective and transmissive mode, respectively. Such an OPV in an OLED absorbs light and converts into electrical power, which reduces the power consumption and also acts as the integrated sensor.
Synthesis and mesomorphic properties of -methylstilbene-based liquid crystals
(2009)
Chang, Chin-Yen
;
Ho, Kang-Wei
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Hsu, Chain-Shu
;
Lin, Chih-Hung
;
Gauza, Sebastian
Six series of -methylstilbene-based liquid crystals, i.e. 4-(4-alkylphenyl)-4'-amino--methylstilbenes (2a-e), 4-(4-alkylphenyl)-4'-cyano--methylstilbenes (3a-e), 4-(4-alkylphenyl)-4'-isothiocyanato--methylstilbenes (4a-e), 4'-(trans-4-alkylcyclohexyl)-4-fluoro--methylstilbenes (5a-e), 4'-(trans-4-alkylcyclohexyl)-4-amino--methylstilbenes (7a-e) and 4'-(trans-4-alkylcyclohexyl)-4-isothiocyanato--methylstilbenes (8a-e) were synthesised. All of these -methylstilbene-based compounds exhibit an enantiotropic nematic phase. Some of the 4-(4-alkylphenyl)-4'-isothiocyanato--methylstilbenes with longer alkyl chains exhibit a smectic A phase. All of the liquid crystals obtained exhibit a wide nematic range and high birefringence of 0.16-0.46. Both series of isothiocyanato-based, liquid crystal compounds 4a-e and 8a-e containing -methylstilbenes revealed much lower melting points and clearing temperatures than their cyano and amino homologues.
Synthesis and mesomorphic properties of fluoro and isothiocyanato biphenyl tolane liquid crystals
(2006)
Liao, Yung-Ming
;
Janarthanan, Narayanasamy
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Hsu, Chain-Shu
;
Gauza, Sebastian
;
Wu, Shin-Tson
Four series of high birefringence biphenyl tolane liquid crystals having a terminal isothiocyanato or fluoro group were synthesized; their mesomorphic properties were studied by optical polarizing microscopy and DSC. These biphenyl tolane compounds exhibit reasonably low melting points and high birefringence of 0.37-0.49. By using these compounds a eutectic mixture was formulated exhibiting a wide nematic range, high figure-of-merit and low viscosity.
Synthesis and mesomorphic properties of super high birefringence isothiocyanato bistolane liquid crystals
(2007)
Liao, Yung-Ming
;
Chen, Hsin-Lan
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Hsu, Chain-Shu
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Gauza, Sebastian
;
Wu, Shin-Tson
Four series of high birefringence bistolane liquid crystals containing isothiocyanato termal groups were synthesized and characterized. As well as the phenyl group, both biphenyl and naphthyl moieties were introduced to enhance the birefringence. These bistolane compounds exhibit reasonably low melting points and high birefringence of 0.5-0.8. A eutectic mixture was formulated from these compounds exhibiting a wide nematic range, high figure-of-merit and low viscosity.
Synthesis of laterally substituted alpha-methylstilbene-tolane liquid crystals
(2008)
Chang, Chin-Yen
;
Chien, Szu-Yuan
;
Hsu, Chain-Shu
;
Gauza, Sebastian
;
Wu, Shin-Tson
Three series of alpha-methylstilbene-tolane liquid crystals, 4-[2-(4-alkylphenyl)-1-ethynyl]-4'-fluoro-alpha-methylstilbene (3a-3e), 4-[2-(4-alkylphenyl)-1-ethynyl]-2'-methyl-4'-fluoro-alpha-methylstilbene (4a-4e) and 4-[2-(4-alkylphenyl)-1-ethynyl]-3'-methyl-4'-fluoro-alpha-methylstilbene (5a-5e), were synthesized and their phase transition temperatures characterized. All the alpha-methylstilbene-tolane liquid crystals exhibit an enantiotropic nematic phase. Compounds 5a-5e, which contain a lateral methyl group at the 3 position of the middle phenyl ring, display low melting points, a wide nematic range and a small enthalpy of fusion. Their potential applications for displays and laser-beam steering are noted.