This Small Business Innovation Research Program (SBIR) Phase II project advances a new electronic paper technology that offers paper-like viewability and high energy-efficiency at very low production costs. Central to the innovation is a reverse-emulsion electrophoretic display (REED) ink, combined with a paper-like nano-porous matrix that was developed in Phase I research. The research objectives for Phase II are: (1) to develop a controlled method for depositing the matrix layer, (2) to finalize critical product design parameters, (3) to develop scalable and high-yield fabrication methods, and (4) to conduct performance evaluation of advanced prototypes. Necessary tasks to achieve these objectives include developing matrix deposition hardware and characterizing layer quality, optimizing the combined formulation of porous matrix and ink, defining specific product geometry and functional specifications, performing process integration and assembly, interfacing with electronics and optimizing driving signals, conducting failure modes and effects analysis (FMEA), and identifying robust operating conditions. The anticipated results of this work is an advanced prototype display that meets performance requirements for electronic shelf label (ESL) applications, as well as a commercially-viable sequence of manufacturing processes for scalable production.
The broader impact/commercial potential of this project are to develop a core display technology that satisfies the readability, power, and cost requirements desired for electronic shelf labels (ESLs), opening new opportunities within the multi-billion dollar global electronic paper market. This project has important implications on society because it can mitigate some of the environmental impact associated with current thin-film display technologies, improve the energy efficiency of electronic displays, and can also lead to reduced paper consumption in a commercially viable way. Technology areas impacted by this innovation include electronic displays, printable electronics, and nanotechnology. Market sectors impacted include display manufacturing and retail. The innovation will further enhance scientific and technological understanding of the behavior of electrophoretic nano-droplets in thin nano-porous media. The enhanced scientific understanding that will be gained from the study of porous matrix and nano-droplet interactions has potential for synergies beyond the realm of electronic displays, with parallels encountered in other areas such as bioseparation and energy conversion processes. Another important aspect of this research is its impact on education, by engaging a university faculty member and a graduate student at one of the nation's minority serving institutions.
This project resulted in the demonstration of an advanced prototype low-cost, power-efficient, paperlike electronic display that uses electro-responsive nanodroplet-based ink within a porous "paper" medium to create images. The paper component is a direct analogue to traditional paper, providing physical structure to the display, a white background, and a porous medium to hold the ink. The paper is infused with the colored ink, which subsequently moves within the paper under applied electric fields to create images. This conceptually simple and low-cost approach to making paper-like electronic displays is enabled by recent advances in nanotechnology and our evolving understanding of nano-scale phenomena. The prototypes were developed with a focus on the specific needs of the Electronic Shelf Label market, and are further adaptable to other formats and applications, including graphical displays. The 7-segment prototypes have paper-like appearance, and a contrast of approximately 6:1. Driven at ± 2.5 V, these power-efficient displays operate on less than 1 µW per square inch. Based on low materials cost and simple manufacturing methods, unit cost in volume production is expected to be significantly lower than even the current lowest-cost display options based on passive LCD. This innovation enhances scientific and technological understanding of the behavior of electrophoretic nanodroplets in thin porous media, and has potential for synergies beyond the realm of electronic displays, with parallels encountered in areas such as bioseparation and energy conversion processes. The technology can mitigate some of the environmental impact associated with current thin-film display technologies, and can also lead to reduced paper consumption in a commercially viable way. Another important aspect of this research is its impact on education, by engaging a faculty member and a graduate student at San José State University (SJSU), one of the nation’s minority serving institutions (ED NCES 2008-156).
