16.3: Development of a Flexible Electronic Display Using Photographic Technology

Abstract

A bistable flexible electronic display has been developed based on photographic technology, processes, and materials. Using photographic film coating techniques, an aqueous cholesteric liquid crystal dispersion, a dielectric layer, and a dark layer were deposited onto patterned transparent conductors on a polymeric web. Second conductors were printed over the active display layers to complete display manufacture in a roll‐to‐roll process. Simple seven‐segment displays and matrix displays have been generated using these techniques. The displays can use contact electronics to eliminate drive cost from the displays. Several prototype applications were demonstrated. Displays produced with these processes were low‐cost, thin, flexible, passively driven, and retained an image without an applied electric field.

Development and applications of cholesteric liquid crystals

“…One way is by using very narrow ribs printed on the flexible surface; this technique has been developed [50] by Fuji and made into a three-layer (blue, green and red) fullcolour e-reader known as FLEPia™. Another method has been to use polymer capsules containing electro-active cholesteric mixtures made using microemulsion techniques [51] related to those used for thermochromic inks and the emulsion coated onto a conducting flexible foil. After evaporation of water, a second conducting foil is laminated on top.…”

Liquid Crystal Display Matrices, Drive Schemes and Bistable Displays

“…There are two methods which are used to encapsulate Ch liquid crystals: phase separation and emulsification. In the emulsification method [70][71][72][73], the Ch liquid crystal, water, and a water dissolvable polymer are placed in a container. The mixture is coated on plastic substrates and then another substrate is laminated on.…”

“…They have much higher viscosities than pure cholesteric liquid crystals and can be coated on substrates in roll-to-roll process [71,72]. They have much higher viscosities than pure cholesteric liquid crystals and can be coated on substrates in roll-to-roll process [71,72].…”

A rugged display: Recent results of flexible cholesteric liquid‐crystal displays

“…It includes an R2R patterning process for the transparent conductive layer, an R2R coating process for the PDCLC, an R2R coating process for the dark layer, and an R2R screen-printing process for the conductive layer. 4 This high-throughput low-capital-requirement process is distinctly different from the conventional capital-intensive sheet-to-sheet flat-panel-display process.…”