Abstract: An illumination system with a prescribed output pattern comprising a light source and an optical lens redirecting the light of the source into an output beam, the lens with multiple surfaces at least one of which has a shape that is not a surface of revolution, the shape generated by the following method: on the Gaussian sphere of directions of the output beam exiting the surface of the lens, in accordance with the prescribed output pattern, establish a first grid of equal-flux zones of solid angle; on a portion of the Gaussian sphere of directions of the light emitted from the source into the interior of the lens, establish a second grid with the same number of equal-flux zones of solid angles as the first grid, with a coordinate-system topology congruent with that of the first grid, such that the zones of the second grid are in one-to-one correspondence with the zones of the first grid, with the flux of each zone in proportion to its corresponding zone of the first grid, according to the local transmittance

Abstract: A light source for backlighting a display panel comprises a light-emitting device such as an incandescent light bulb or LED array disposed within a cavity having diffusely reflecting walls and an aperture. A diffuser and brightness enhancing film are situated proximate the opening of the aperture which illuminates the display to be backlit. Preferably, light emerging from the aperture is substantially uniform in intensity and color, and in one embodiment, a color filter is employed to whiten the light emerging from the aperture. One embodiment has an aperture in which the ratio of the area of the aperture to the sum of such area and the surface area of the cavity is at least 0.05. In this embodiment, the ratio of the depth of the cavity to an edge to edge dimension of the cavity is at least 0.1.