Cavity reflector light injection for flat panel displays

A light mixing system includes a transparent waveguide having a reflectorized edge, a light input edge and a light output edge opposite the reflectorized edge. The light input edge receives light of different colors from two or more light sources. The received light of different colors is totally internally reflected from opposite major surfaces of the waveguide. Formed inside the waveguide are a plurality of cavities bounded by walls substantially parallel to the edges and substantially orthogonal to the major surfaces of the waveguide. Interaction of the received light of different colors with one or more of the cavities and the reflectorized edge mixes the light of different colors before exiting the light output edge.