Study On Freeform Lens Design For LED Extended Sources

As a new generation of green solid lighting source, LED is rapidly used in various lighting situations due to its small size, long life, high efficiency, etc. Because of the LED luminescence properties of lambert distribution, LED lighting applications need to rely on secondary optical distribution design. According to the e xte nded conservation law and the theory of marginal ray, the free-form surface lens design of the ideal point source is put forward and the development constantly. In this paper,the free-form lens of uniform illumination and the total reflection free-form surface collimating lens are designed based on point source is designed,and it has good results. However, the single LED cannot be directly instead of traditional light source for lighting due to the less brightness, the methods based on LED point source cannot satisfy the trend of lighting system. Therefore, the freeform surface lens design method in view of the extended light source is put forward in this article, and the main work includes the following several aspects:1. The research on free-form surface lens realizing uniform illumination based on LED extended source. The energy of any point of the goal receiving surface is determined by the edge of the light according to the theory of marginal ray, so the free-form surface lens design method is proposed for LED extended source.2. The research on free-form surface lens realizing collimating based on LED extended source. Through the introduction of the design of si multaneous multiple surface method, the optical system of LED extended source is studied. By identifying the value relationship of a certain size of extended source and target surface, realizing LED extended source beam collimation by mathematical calculated of birefringence lens based on simultaneous multiple surface method.3. The research on optical system of small beam for high-power COB light. In this paper, a kind of optical system is proposed realizing small beam emergence with the light radius of 8.6mm by studying methods of light collimating lens design. Compound parabolic concentrator is used to concentrate extended source with lambert luminous to a certain angle, then achieve the effect of small beam emergence by simultaneo us surface method.Finally, On the basis of research on design methods of extended source above, the street lighting lens based on the LED extended source is designed. Firstly, the idea of grid partition method for ideal point source is applied, and the corresponding lamp lens is designed. On this basis, the feedback optimization algorithm is studied, and the feedback coefficient is added to illumina tion value of the goal surface, using the grid method iterative operation again to realizing street lighting based on extended source.