Passive high efficiency variable reflectivity image display device

Abstract

A variably reflective display device amenable to multiple pixel display applications. Each pixel has at least one element having a reflective state in which incident light undergoes total internal reflection, and having a non-reflective state in which total internal reflection is prevented. Such prevention is achieved by interfering with (scattering and/or absorbing) the evanescent wave adjacent the surface of the element. For example, a member can be positioned adjacent the element and deformed between first and second positions. In the first position a gap remains between the member and the element to allow the evanescent wave to behave normally. In the second position the member is in optical (but not atomic) contact with the element, such that the member interferes with the evanescent wave and thereby prevents total internal reflection. In one embodiment, each pixel is a grouping of retro-reflective elements, such as corner reflectors. An elastomeric material is provided adjacent each grouping. If a gap is left between the grouping and the elastomeric material, the grouping continues to exhibit total internal reflection. But, if the elastomeric material makes optical contact with the grouping, the evanescent wave is absorbed or scattered and hence total internal reflection is prevented, which in turn prevents reflection of incident light. Thus, the "pixel" formed by the corner reflector grouping is "off" if it makes optical contact with the elastomeric material, and "on" if a gap is left between the two.

Dependencies are inferred from the claim text.