Patent ID: 7450799

Claim:
A system for enhancing a contrast ratio of flat panel displays that utilize selectively controlled frustrated total internal reflection to turn pixels on and off, comprising: a plurality of movable elements, operable for frustration of total internal reflection by way of suitable matching of refractive index between the plurality of movable elements and a waveguide in which total internal reflected light is trapped; and a plurality of corner-cube retroreflector structures added to a surface of each of the plurality of movable elements comprising a pixel, such that a vertex of each of the plurality of corner-cube retroreflector structures is oriented to face the waveguide in which total internal reflected light is trapped and available for selectively controllable frustration, entailing optical coupling and subsequent emission toward an observer's eye, wherein facets forming each of the plurality of corner-cube retroreflectors are at right angles to one another, and wherein each vertex of the plurality of corner-cube retroreflector structures is truncated and flattened so as to form a flat planar surface, nominally in a shape of an equilateral triangle, parallel to a surface of the waveguide, such that each said flat planar surface is in spaced-apart relation to the waveguide when the pixel is in its quiescent state at a distance sufficiently large to prevent frustration of total internal reflected light within the waveguide, and is propelled in tandem with a main body of the movable element into contact or near-contact in an active state of the pixel, thus frustrating total internal reflection and causing the pixel to emit optical energy heretofore trapped in the waveguide by selectively controllable means.