Patent ID: 8160409
Filing Date: 2012-04-17
Classification: G02B,G03B,H04N,H04W

Abstract:
1. A light guide comprising: an input slab for expanding a projected image laterally within the input slab as light travels between an input end and an output end; and an output waveguide arranged to receive rays from the output end of the input slab, and to emit the rays at a point on an output face of the output waveguide that corresponds to an angle at which the rays are received, in which: the input slab and the output waveguide are tapered to decrease in thickness in a general direction of ray travel; and an angle of taper of the input slab and an angle of taper of the output waveguide are controlled so that rays of different angles travelling between the input end of the input slab and the point where the rays leave the output face undergo a same number of reflections; wherein the angle of taper of the input slab is constant from the input end to the output end; and the angle of taper of the input slab is less than the angle of taper of the output waveguide.