针对传统点聚焦菲涅耳透镜聚光分布均匀性较差以及聚焦光斑形状与太阳能电池片不匹配的缺点, 提出了一种分区多焦点叠加方形光斑均匀聚光菲涅耳透镜的设计方法。在传统圆形同心环带点聚集菲涅耳透镜的基础上截取4个缺角等腰直角三角形菲涅耳透镜单元,做无缝拼接形成分区域四焦点叠加的方形光斑均匀聚光菲涅耳透镜, 通过这4个区域光的叠加有效改善了聚光的均匀度。基于光线追迹法, 采用TracePro光线模拟软件模拟并分析了环距、缺角弦长、腰长等透镜结构参数对聚焦光斑形状、聚光均匀度、辐照度等光学性能参数的影响。结果表明采用该方法设计的透镜聚焦光斑形状为方形, 聚光均匀度高达90%以上。

Aiming at defects of the poor uniformity of spotlight distribution and the mismatching between the focusing spot shape and solar cells for the traditional point focusing Fresnel lens, a Fresnel lens is proposed to uniformly focus square spot by sub-region multi-focus superposition. Four angle-missing isosceles right triangles were intercepted from the traditional circular concentric rings spot focusing Fresnel lens and spliced seamlessly to form a Fresnel lens uniformly focusing square spot by sub-region four-focus superposition, and the concentration uniformity is improved effectively by light superposition in the four parts. The ray tracing method was used to simulate and analyze the influence on the optical performance parameters such as the shape of the focal spot, the concentration uniformity and the irradiance, which is caused by the structure parameters of lens such as ring spacing, angle-missing chord length and waist length. The results show that the focus spot shape of the lens designed by this method is square, and the concentration uniformity is higher than 90%.