Freeform Fresnel lenses with a low number of discontinuities for tailored illumination applications.
Freeform Fresnel lenses with a low number of discontinuities for tailored illumination applications.
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DOI：
10.1364/oe.397983
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发表时间：
2020-08
期刊：
影响因子：
3.8
通讯作者：
K. Desnijder;P. Hanselaer;Y. Meuret
中科院分区：
文献类型：
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作者：
K. Desnijder;P. Hanselaer;Y. Meuret
自由曲面透镜设计领域的大部分工作都集中在寻找连续自由曲面的设计算法，将任意的入射光分布转化为任意的出射光分布。所得到的连续透镜表面的形状完全取决于为其量身定制的光源和目标光分布。在某些情况下，这将导致依赖于应用的大体积光学元件是不实际的。菲涅耳透镜可以有一个小得多的体积，但在自由曲面透镜的情况下，不是直截了当的设计。提出了一种基于同心自由曲面段的自由菲涅耳透镜的设计方法。与现有的菲涅耳式自由曲面透镜相比，这种透镜的不连续点要少得多。更少的不连续意味着更少的杂散光，由于当前制造过程中不可避免的舍入误差。首先说明了新的设计方法，然后举例说明了在远场具有矩形目标分布的自由菲涅耳透镜的设计方法。
Most work in the field of freeform lens design has been focused on finding design algorithms for continuous freeform lens surfaces which transform an arbitrary ingoing light distribution into an arbitrary outgoing distribution. The shape of the resulting continuous lens surfaces depends fully on the source and target light distribution for which the lenses are tailored. In some cases this results in large, voluminous optical components which depending on the application are not practical. Fresnel lenses can have a much smaller volume, but are not straightforward to design in the case of freeform lenses. This paper demonstrates a new method to design freeform Fresnel lenses based on concentric freeform segments. Such lenses have a much lower number of discontinuities compared to already existing Fresnel-type freeform lenses which are based on an array of facets. Less discontinuities means less stray light due to the unavoidable rounding errors with current manufacturing processes. The new design method is first explained, and then illustrated for a freeform Fresnel lens with a rectangular target distribution in the far-field.