Optimal design of a nonimaging TIR doublet-lens illumination system using an LED source

We consider the problem of designing illumination optics to transfer flux from an LED source into a rectangular target aperture. An important constraint on this design was that it provide a large working distance between the source and the target aperture. An optimized compact nonimaging system consisting of an aspheric totally-internally-reflecting (TIR) lens along with an aspheric sin-let was developed to provide high flux-transfer efficiency with the required working distance. A global optimization procedure was used to search a 65-dimensional parameter space for the set of optical-component shape and positioning parameters providing maximum performance, while satisfying the design constraints. A total source-to-target flux-transfer efficiency of 85.0% was achieved by the design, assuming ideal AR coatings on all refractive surfaces.