Patent attributes
The application of microstructures which improve the quality of light available to the viewer of an optical display system, or any display which works on the concept of moving one surface into direct contact or close proximity of a light guide to extract light through frustrated total internal reflection. Optical microstructures are introduced on one or both of the surfaces of the active layer to enhance its performance. Since the active layer has both an input and an output function, means for enhancing both are presented. The input function to the active layer occurs on the internal surface, so this is where the present invention adds a collector-coupler, a means for facilitating the migration of light from the waveguide into the active layer. The output function occurs on the external surface, where the present invention adds a collimator, a means for both increasing the probability that a light wave will be released from the active layer, and improving the apparent intensity by redirecting light waves so that more of them reach the viewer. Compound microlenses on the internal surface of the active layer can serve as both collector-couplers and collimators, substantially improving light extraction from the light guide and light distribution to the viewer. Depositing a reflective or colored material in the interstitial spaces between these compound microlenses improves the contrast ratio and mitigate pixel cross-talk. The opaque material can be conductive for use in actuating the display.
