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WAVEGUIDE LIQUID CRYSTAL DISPLAYS AND OPTICAL DIFFRACTION GRATING BASED ON FLEXOELECTRIC LIQUID CRYSTALS AND POLYMER STABILIZED LIQUID CRYSTALS

Shin, Yunho
http://rave.ohiolink.edu/etdc/view?acc_num=kent1682349736015146

Abstract Details

2023, PHD, Kent State University, College of Arts and Sciences / Materials Science Graduate Program.
Waveguide liquid crystal display (WLCD) is a newly developed transparent display technology. Since polarizers and color filters are not necessary for the WLCD, high transparency is easily reached. A light-emitting diode (LED) is installed on the edge of the display and the produced light is coupled into the display. When no voltage is applied, the liquid crystal is uniformly aligned and is transparent. The incident light propagates through the display in waveguide mode due to the total internal reflection at the interface between the substrate and air, and no light comes out of the viewing side of the display. The display appears transparent. When a voltage is applied, the liquid crystal is switched to a micrometer-sized polydomain state and becomes scattering. The incident light is scattered out of the waveguide mode and comes out of the viewing side of the display. We developed a few methods to improve the performance of the waveguide display. First, by using patterned photo-polymerization or patterned ITO electrode, the scattering efficiency of the liquid crystal in the voltage-on state is significantly enhanced. Second, the spatial uniformity of the light intensity of the display is significantly improved by the light waveguide plate. Third, we achieved 8 inch full color transparent light waveguide LCD prototype that utilizes field sequential color (FSC) scheme to display full color images. Fourth, we developed a light waveguide LCD based on the flexoelectric effect using dimer, which exhibits high contrast ratio. Lastly, based on the flexoelectric effect we developed a reconfigurable liquid crystal diffraction grating whose diffraction angle and efficiency can be controlled by the applied voltage. The light waveguide liquid crystal transparent display has the merits of high contrast ratio, suitable driving voltage, and a sub-milli second ultrafast response time. It does not use polarizers and color filter as in conventional LCDs. It also has an ultrahigh transmittance near 90% in the voltage-off state. It is very suitable for transparent display, which can be used for head-up display and augmented reality display
Dengke Yang (Advisor)
Philip J. Bos (Committee Member)
Songping Huang (Committee Member)
Sam Sprunt (Committee Member)
Hiroshi Yokoyama (Committee Member)
178 p.
Materials Science; Optics; Physics
Liquid Crystal, Liquid crystal dimer, Liquid crystal polymer, Flexoelectric effect, Optics, Liquid Crystal Display, Light waveguide, Polymer stabilized liquid crystals, Flexible display, Transparent display, Color sequential. Tunable liquid crystal diffraction grating

Recommended Citations

Citations

  • Shin, Y. (2023). WAVEGUIDE LIQUID CRYSTAL DISPLAYS AND OPTICAL DIFFRACTION GRATING BASED ON FLEXOELECTRIC LIQUID CRYSTALS AND POLYMER STABILIZED LIQUID CRYSTALS [Doctoral dissertation, Kent State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=kent1682349736015146

    APA Style (7th edition)

  • Shin, Yunho. WAVEGUIDE LIQUID CRYSTAL DISPLAYS AND OPTICAL DIFFRACTION GRATING BASED ON FLEXOELECTRIC LIQUID CRYSTALS AND POLYMER STABILIZED LIQUID CRYSTALS. 2023. Kent State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=kent1682349736015146.

    MLA Style (8th edition)

  • Shin, Yunho. "WAVEGUIDE LIQUID CRYSTAL DISPLAYS AND OPTICAL DIFFRACTION GRATING BASED ON FLEXOELECTRIC LIQUID CRYSTALS AND POLYMER STABILIZED LIQUID CRYSTALS." Doctoral dissertation, Kent State University, 2023. http://rave.ohiolink.edu/etdc/view?acc_num=kent1682349736015146

    Chicago Manual of Style (17th edition)

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© 2023, all rights reserved.
This open access ETD is published by Kent State University and OhioLINK.