利用复合抛物面与自由曲面相结合的方法，设计出一款体积小、能效高的LED 光源准直配光透镜。将LED 光源发出的光线分两部分分别进行配光设计。光源发出的一部分发散角为0o~20o 的光线经过球冠折射收缩发散角后再利用自由曲面准直；光源发出的另一部分发散角为20o~80o 的光线经过复合抛物面折射收缩发散角后再经自由曲面准直。结果显示，LED 光线经此复合型准直透镜后光束发散角小于4o，光能利用率达90%，可满足目前对光源远距离准直需求。

By combining the compound paraboloid with free-form surfaces，a small, energy-efficient collimating lens based on LED light source is designed. The optical design is carried on in two parts separately. One part of the light, whose divergence angle between 0o and 20o, is collimated through a spherical cap contracted the divergence angle and a free-form surface. The other part of light, whose divergence angle between 20o and 80o, is collimated through a compound paraboloid contracted the divergence angle and a free-form surface. The results show that, light angle is less than 4o through this complex collimating lens, and the efficiency of light energy utilization is up to 90%, which could meet requirements for light collimation in current distance.