A luminaire includes a light waveguide grid including an array of waveguides coupling respective illumination light source emitters of a general illumination device with respective gaps between respective pixel light emitters of an image display device. Each waveguide has a housing that includes an input interface optically coupled to the respective illumination light source emitter to steer illumination lighting from the illumination light source emitter. The housing also includes an output interface opposing the input interface and optically coupled to one or more gaps between pixel light emitters. The housing further includes at least one reflective wall having an internal reflective surface encompassing and extending from the input interface and the output interface. The structure of the waveguide may be optimized and/or additional technologies added to reduce optical losses and improve overall illumination efficiency of the luminaire.