Development of novel electronic inks for print-like color reflective display

Electronic inks have been developed for each primary color to serve as the imaging fluids for novel electrokinetic display (EKD) technology. EKD uses in-plane optical effects and out of plane switching fields to switch between color and clear states, allowing a stacked approach of color layers for a full-color display. The need for compaction into small volumes to achieve a clear state and repeated cycles of spreading and compaction creates challenges for the stabilization and charging of colorant particles. Surfactants play a critical role in determining system behaviors. This paper reports on the latest findings of surfactant influence on optical switching and bistability characteristics of display performance for some proprietary surfactant formulations. HP's combination of novel device architecture, proprietary inks, and R2R manufacturing platform enables the required attributes for electronic media such as low power, transparency, print-quality color flexibility, robustness, and scalability at low cost. The innovations described in this paper are applicable to either segmented or pixilated electronic media, and are currently being developed for both digital signage and electronic paper markets.