An optical panel includes a plurality of stacked optical waveguides bound by
black
cladding to collectively form an inlet face and an opposite display screen. An
inlet diffuser has an inlet surface, and an opposite outlet surface adjoining the
inlet face of the waveguides. Asymmetric diffusion of image light is effected by
the inlet diffuser for increasing field of view, with ambient light being absorbed
through the display screen for increasing contrast. Alternatively, an outlet diffuser
may be provided at the display screen to complement the inlet diffuser by differently
diffusing the image light spatially at the display screen.