基于光源利用率的投影式汽车前照灯近光配光设计

Design of Projector Headlamp Low Beam Distribution Based on the Light Utilization Rate

由于常用旋转或复合椭球面的投影式前照灯多采用反射器和挡板的近光配光方式,具有光源利用率较低的不足,为此本文研究了一种变焦点的椭球面反射器设计方法,该方法通过改变反射器曲面的焦点和参数来构造一种基于无挡板的投影式汽车前照灯近光反射器。本文首先分析了投影式椭球面反射器光源与焦点位置关系对近光光配的影响变化规律,其次阐述了变焦点椭球面反射器的设计基本原理,然后建立了具有五个区域的反射器椭球面的三维方程式,并构造了椭球面上经纬线的变化函数,通过在MATLAB中计算得到曲面上空间点分布,将空间点分布导入三维软件Rhino中得到椭球面反射器三维模型,最后将三维模型导入光学软件LucidShape中,进行光学模拟,结果表明与传统设计方法相比,采用该方法设计的汽车前照灯反射器的近光光利用率可提高20%以上,且水平方向照射范围在±20°以上,满足GB4599—2007汽车用灯丝灯泡前照灯法规要求。

Due to the rotating or composite ellipsoid-like reflectors and baffles commonly used in projector headlamp low beam light distribution, the light utilization rate is low. In this paper a design method of a variable focus ellipsoidal reflector is studied. This method constructs headlight beam reflector based on a no baffle projector headlamp by changing the focus of the reflector and the surface parameters. The paper first analyzes the rule of influence on the low beam light distribution about the relative position of the light source and focus in a projection ellipsoid reflector type. Secondly the basic design principles of the variable focus ellipsoid reflector are described, then a three-dimensional formula of the ellipsoid reflector with five regional is set up. And the function of the latitude and longitude lines on the ellipsoid surface is constructed. The result of the distribution of spatial point on the surface is obtained by calculating in MATLAB, and then the result is put into the three-dimensional software Rhino to get the three-dimensional model of the ellipsoid reflector. At last simulate the model in the optical software LucidShape. The result shows that, compared with the traditional design method, the new method studied in the paper can increases the headlamp reflector light utilization rate by more than 20% , and the illuminated range is over _＋ 20~ in the horizontal direction. The GB4599--2007- Motor vehicle headlamps equipped with filament lamps regulatory requirements are fulfilled.