Study On Optical Design And Illumination Performance Of Extended Light Source Collimated Illumination System

In the special lighting field such as ultra-long-distance collimated lighting,high-power white light-emitting diode(LED)light source has extremely high use value.However,since the size of the light-emitting surface of the light source is not negligible,it belongs to the extended light source,so it is bound to cause the divergence of the outgoing beam of the collimated illumination system when used,and the divergence characteristic will affect the illumination distance and the illumination effect.In view of the above problems,this paper studies the following contents from three aspects: theoretical derivation,software simulation and experimental testing.(1)Based on Fermat's principle,the analytical expression of collimating plano-convex lens is derived,and a surface design algorithm based on free-form surface construction technology is proposed.(2)Based on the theory of imaging optics,the calculation formula of the divergence angle of the outgoing beam in the extended light source collimated illumination system is derived.The influence of the structural parameters of the extended light source collimated illumination system on the divergence characteristics of the outgoing beam is studied.Based on the theory of the divergence characteristics of the outgoing beam,the direct illumination system is continuously studied,and the expressions of the limit illumination distance and the illuminable radius of the extended source collimated illumination system are derived.The effects of the lateral and longitudinal dimensions of the optical system on the limit illumination distance and the illuminable radius are analyzed separately.(3)The above theory was simulated in optical software,and the simulation results were in agreement with the theoretical expectation.On this basis,the lens with the optimal structural parameters is solidly processed,and the high-power LED light source produced by CREE is packaged into a searchlight for experimental test,which further confirms the correctness and practicability of the theory.(4)According to the theory of this paper,a super long-range searchlight is designed.The searchlight has a lateral dimension of 75 cm and an electric power of 149 W.It can realize a circular area with 35.1m and an illumination with a radius of 1.32 lx at 2km,and the beam divergence angle.It is 1°,the collimation is extremely high,the illumination uniformity is excellent,and various indicators meet the design requirements.The research content of this paper reveals the key factors affecting the limit illumination distance in the extended light source collimated illumination.It has great theoretical guiding significance for the design and manufacture of ultra-long-distance searchlights,high-speed vehicle lighting,search and rescue lights,and stage follow-up lights.