A method of fabricating a light guide assembly includes the steps of providing an array of generally frustum-shaped light guides made of a light-transmissive material, providing an optical isolation frame of interconnected slats made of an opaque material, wherein the slats are arranged and profiled to correspondingly match the gaps between the light guides and the outer gap around the periphery of the light guide array, and bonding the light guide array and the optical isolation frame to each other.