Zoomable beamspreader with matched optical surfaces for non-imaging illumination applications

Abstract

A zoomable light beam spreader comprising first and second multiple-lens arrays includes a plurality of plano-convex lenses in correspondence with a plurality of plano-concave lenses having matched, curved optical surfaces. In a zero-power state, the two multiple-lens arrays are very closely spaced so that the matched convex and concave surfaces effectively cancel each other optically but, as the two arrays are separated coaxially along the axis of a light beam, beam divergence angle increases as a function of the distance of separation. A large amount of beam divergence is obtained when the curved surfaces of the plano-concave lenses of the second array are positioned beyond the focus points of the plano-convex lenses of the first array.