为了解决现有照明光纤束的发光二极管(LED)透镜耦合器的厚度和均匀性问题,根据菲涅耳光学理论和全反射原理设计了一款新型菲涅耳透镜耦合器。利用菲涅耳旋转曲面和自由曲面全反射旋转面,将LED朗伯光源发出的光束整形得到平顶光束,再耦合到光纤束中实现均匀照明。采用1 W的3535白光LED作为光源,在TracePro软件中对所设计的菲涅耳透镜耦合器模型进行光线追迹仿真。结果表明,当菲涅耳透镜最大直径为14.9 mm、厚度为7.8 mm、输出光束发散角度为60°时,在耦合距离为2 mm的接收屏上得到直径10 mm、照度均匀性达92%的均匀光场。

In order to solve the problem of the thickness and uniformity of the light emitting diode (LED) lens coupler for the existing lighting fiber bundle, a new type of Fresnel lens coupler according to the Fresnel theory and the total reflection principle is designed. The Fresnel rotating surface and the free-form surface total reflection rotation surface are used to shape the light beam emitted by the LED Lambert light source to obtain a flattened light beam, which is then coupled to the fiber bundle for uniform illumination. Using 1 W 3535 white LED as the light source, TracePro software is used to simulate the Fresnel lens coupler model. The results show that when the maximum diameter of the Fresnel lens is 14.9 mm, the thickness is 7.8 mm and the output beam divergence angle is 60°, a uniform light field with diameter of 10 mm and luminance uniformity of 92% is obtained on a receiving screen with a coupling distance of 2 mm.