Illumination optical design using non-coherent sources is of major interest for sensing applications requiring a uniform illumination. We present the development of a custom biconic lens array, enabling beam shaping of a halogen source array to a rectangular uniform illumination. First, the tungsten halogen sources were accurately modelled considering the nearfield emission pattern and broadband spectrum. Following, the illumination lens array is optimized, including a study on the optimal arrangement and pitch of the array, and ensuring a manufacturable design by taking the optical and mechanical tolerances into account. The optimized lens array comprises of custom lenses (Ø 20 mm) featuring a first spherical surface and a second biconic surface with different radii of curvature and aspherical coefficients (up to the 8th order) in the X and Y direction. A spatial uniformity, defined as the standard deviation of the flux distribution, of 0.0002 was achieved within the envisioned illumination area of 50 x 20 mm², being close to a perfect uniformity considering a targeted value of 0. Finally, the aspheric biconic lens is manufactured using ultraprecision diamond tooling (Nanotech 350FG), and its performance is successfully validated in a laboratory demonstrator setup, giving rise to an optimized and uniform halogen source illumination.
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