A novel reflective image display using total internal reflection

We are developing a new reflective display technology, based on total internal reflection, which achieves a large difference between the maximum and minimum reflectance values. This yields a surface with greatly improved legibility under a wide range of illumination conditions. Such devices can display an image with a maximum reflectance ranging from 55% under uniform background illumination to over 85% under common non-uniform illumination conditions, even at viewing angles greater than 80degrees from the surface normal. This approach, which we call 'CLEAR' (Charged Liquid Electro-Active Response), uses polymeric microstructures to efficiently redirect incoming ambient light back toward the viewer. One advantage of this technique is the ability to achieve bright, full-color images over a wide range of viewing angles, much like ink printed on paper. The displayed image can be updated rapidly since switching from the reflective state to the absorptive state requires only about a half-micron of motion of absorbing material into the evanescent field associated with TIR. This new approach offers significant advantages in a number of reflective display applications. (C) 2004 Elsevier B.V. All rights reserved.