New Developments in Full Color Flexible Reflective Cholesteric Liquid Crystal Displays

Abstract

We present recent developments in full color bistable reflective cholesteric liquid crystal displays on flexible substrates. The approaches include stacking of three reflective layers (red, green and blue) on top of each other or a spatial separation (area sharing approach) of reflective layers from each other within one layer. Stacking is possible due to selective reflection properties of cholesteric layers. Each layer of the display can be addressed independently to vary the reflectance of each color yielding many possible colors. The advantage of the approach is that the display is producing a full brightness of each primary color. The advantage of the area sharing approach is its superior contrast and simplicity, as only one layer is required; that can significantly reduce the cost of the device. The developed cholesteric materials for full color displays can be easily laminated between the flexible substrates, and, possible, coated or printed. We are currently successfully implementing the developed technologies enabling low cost, low power, low weight and rugged display applications, such as writing tablets, electronic skins and electronic books.