Flexible Polymer Bistable Cholesteric Liquid Crystal Color Display Unit

In the modern information display technology, liquid crystal display has already dominated, especially for polymer bistable reflective cholesteric liquid crystal displays, its backlight is not required, and can achieve flexible display. In the field of large-capacity display but not require fast update information, it has been widely studied and applied.First of all, form the starting of the combination of theory and experiment, this paper verified the Bragg reflection. The chiral materials were incorporated into nematic liquid crystal with different concentration, to form cholesteric liquid crystal with different pitch. Berreman 4*4 matrix method and MATLAB were used to calculate the reflectance spectrum, and the relationship between pitch and reflectance spectrum was obtained. The reflectance spectrum of this liquid crystal was tested by fiber-optic spectrometer. Through comparative analysis, it is consistent with the theoretical value. In the production of flexible display unit, the flexible substrates need to roll up and down. As the speed limit, it is difficult to buy the laminating machine in the market to meet the requirements. So the laminating machine for the production of flexible display unit has been developed by author. And the machine can achieve the direction of change, speed adjustable, and the slowest wheel speed can reach 20cm/hour. The device has been developed and has been making for flexible bistable device.In this dissertation, polymerization induced phase separation (PIPS) has been applied to prepare polymer dispersed liquid crystal (PDLC) and polymer network cholesteric liquid crystal (PNCLC).For the PDLC display unit, the main content of the monomer, box thickness, light intensity and temperature have been studied, to find the affect to the optical characteristics of the PDLC display unit. Through the contrast of Photoelectric Properties, when the mixed polymer monomer content is 30%, box thickness is 13μm, UV light intensity is 0.550mw/cm2 and the temperature is 25℃, the experimental samples have the best optical and electrical properties.For the PNCLC display unit, at first, polymer network and substrate surface treatment have been added. And then the PNCLC display units'reflective spectral has been studied, and other factors affected on the PNCLC optical properties have been analyzed, such as monomer concentration, box thickness, exposure, and exposure temperature. Finally through the three RGB color cholesteric liquid crystal display unit stack method to achieve color display, and it has been researched and analyzed. It has been found that the polymer network and the surface's concave and convex structure of the substrate can broaden the reflection spectrum. And this provides an important basis for the feasibility and methods to PNCLC color display or white display.