Design Of Projector Headlamp Beam Distribution

Headlamps is the core of automotive lighting system and affects directly the driving safety. At present, structure of car headlamps has two kinds of forms: projection and freeform surface. The freeform surface structure is more complex and processing is difficult, while projection system is relatively simple and it can obtain clear cut-off line for low beam owing to baffle structure. Projection system is applied widely in the field of automobile headlamps lighting, because it can assure your driving more safe.First, the development history of light source was stated on the automobile lights and the application of different light source was introduced in different periods.The evolution of structure and characteristic of automobile headlamps were introduced, at the same time design theory of automobile lamps were stated.According to the of theory of projection system design and the regulation of GB standard for headlamps light distribution, a projection low beam system model was established in optical simulation software Lucid Shape, the influence of different diameter and focal length for low beam distribution was analyzed in the software.Finally through comparing the light type and test point data, the best light distribution effect of the low beam was obtained when lens diameter is 70 mm and the focal length is 50 mm.A projection low beam system was designed with halogen lamp. The system was composed of elliptic reflector, freeform surface reflector, baffle and aspheric lens. Finally the designed entity models were imported and analyzed in the optical software Lucid Shape, result shows that the light distribution meet requirements of the GB 4599-2007, clear cut-off line is obtained at the same time, the light efficiency is increased by 12%.According to the properties of LED light source and the design theory of automobile headlamps, a kind of automobile headlamps was designed with LED light source, its structure was more compact. The designed entity models were analyzed in Lucid Shape, simulation result shows that the low beam and high beam are all meet the requirement of GB25991-2010 regulations for light distribution,advantage of the headlamps system is more simple structure and it can save more design space and cost.