Fundamentals and Applications of Large Area Multi-spectral state Electrophoretic Panels for Displays and Smart Windows

Large area electro-optic switches are increasingly important, including flat panel displays and the more recently emerging technology of smart windows. However, these types of switches are typically limited to switching between only two states, such as a clear and an opaque state. Therefore optical performance and functionality of large-area electro-optic devices could be significantly improved, if switches were developed that could provide modulation of multiple spectral states. Simple solutions such as adding a color filter array onto a clear/opaque switch are not the ideal solution, as seen in displays where color filters reduce the display brightness by blocking more than 2/3rds of the visible spectrum. There is a clear need to develop alternate electro-optic switches, especially those that broaden the spectral capability within the switch without a significant increase in complexity of the device or increase in optical loss. If such a novel switch could be realized, full-color displays could be bright enough to even be easily read in sunlight, and smart windows could be made into more compelling products by allowing additional desirable lighting features such as control of color temperature.;In this dissertation a completely new bi-primary pixel switching mechanism is demonstrated that can switch one single pixel into 4 color states (2 color states along with black and white). The approach uses two-particle, two-colored electrophoretic inks along with novel device architectures which could simplify large area device manufacturing. For displays, this approach provides 2X higher brightness and reflectivity than the already existing side-by-side RGBW color system approach. For smart windows, dual spectrum control is enabled (color temperature, visible vs. IR, etc.), finally enabling smart window technology which provides features not easily possible with simple mechanical blinds. Importantly, this new structure is highly manufacturable, requiring no alignment, and can be fabricated by micro replication and roller printing methods. This dissertation spans fundamental theory, through experimental electrophoretic characterization, through compelling integration and performance demonstrations.