Etendue conserving light shaping using microlens arrays with irregular lenslets

Light shaping optics often generate continuously varying or homogeneous far-field distributions: Diffusers or free-form beam shapers are well-suited for transforming a given incident angular distribution into a continuous far-field distribution, while etendue conserving fly´s eye condensers excel in producing homogeneous top-hat far-fields, independent of the incident spatial and angular light distribution. The proposed optics combines the advantages of these light shaping optics in generating continuously varying far-field distributions independently from the incoming light distribution while conserving etendue. The light shaping systems consists of a high fill factor tandem microlens array featuring irregular lenslets with individual aperture size and individual decentration of lens vertex and and lens aperture w.r.t. array channel axis. We present design examples to be realized as monolithic polymer-on-glass tandem arrays, mastered by grayscale lithography. Applications of this light shaping approach are LED-spotlights with particular farfield specifications and small design envelope e.g. for automotive or general lighting.