Optical device for modifying the angular and spatial distribution of

Abstract

A deconcentrating optic has an input aperture positioned near a point of minimum focus of a reflector, and has an output aperture which is larger than the input aperture. An inner surface connects the two apertures of the optic. The surface is reflective to visible light, and is shaped to decrease the angles of incident light rays from the reflector so that an emerging light beam is bounded by a cone the angle of which is less than or equal to the acceptance cone of a projection lens. The size and shape of the output beam is such that the object lying in the projection plane of the lens is fully illuminated but not overfilled. The inner surface of the reflecting optic may be selectively perturbed so that the object plane of the projection lens is uniformly illuminated. The general shape of the reflecting optic's inner surface may be parabolic, elliptical, hyperbolic, circular, conical, or combinations of these shapes. The perturbations of the inner surface may be protrusions on or indentations in the inner surface, and may have shapes that are circular, planar, triangular, parabolic, random, or any other shape. A solid deconcentrating optic is transparent throughout, having a reflective coating on its exterior surface except for an input and an output aperture surface, which may be curved to cooperate with reflections from the reflective coating on the exterior surface to produce the desired output irradiance distribution.