LEDs that are used today in general lighting applications provide high luminous flux from small packages which can result into high peak luminance and glare. The use of diffusors allows to reduce peak luminances, but these components do not allow accurate control over the resulting intensity pattern as is possible with non-imaging lenses for lowétendue sources such as LEDs. In this paper a new design method is presented to create a rotational or transverse symmetric segmented lens which results in a reduced peak luminance but still allows excellent control over the resulting intensity distribution. Each segment of the lens spreads out the light in a certain angular range, but the different contributions of each lens segment result together into the desired target intensity distribution. The design method is based on the iterative optimization of a linear transformation of a source intensity distribution into a target intensity distribution, starting from a transformation that yields maximal light beam spreading.

No abstract