Flexible ferroelectric liquid-crystal devices containing fine polymer fibers

A new flexible ferroelectric liquid-crystal-display device with gray-scale capability has been created by using submicrometer-diameter polymer fibers. The polymer fibers, which are formed by photopolymerization of aligned monomer molecules in liquid crystal, align the ferroelectric liquid crystal and mechanically support two flexible thin plastic substrates. The composite film made of liquid crystal and polymer with a thickness of 2 μm was formed between the plastic substrates by using a fabrication method consisting of coating, lamination, and ultraviolet irradiation processes without the conventional gap-forming and injection processes. The fabricated flexible device revealed gray-scale capability due to the change in spatial distribution of micrometer-sized binary-switching liquid-crystal domains. From the polarizing microscope observation, it was found that the switching domains are generated and expanded from the areas with poor polymer density. The experimental results indicated that the polymer fibers spatially modulate the threshold voltage for molecular switching. Our device exhibits great potential for flexible large-sized light-weight motion-image displays.