Designing Method of Projector Type Vehicle Headlamp Reflector Based on the Variable Ellipse Profile

Since light source utilization rate of projector type headlamp is low, and its dipped beam has the requirement that extends about ± 20° in horizontal direction. A designing method of variable ellipse profile is presented for the surface of projector type headlamp, which describes the light distribution principle of reflector and analyzes the effect of ellipses curve on headlamp\´s light distribution. Then, after deriving the reflector profile and fitting the space curve, we gain variation ellipse surface. In the end, we simulate a projector type system with this reflector in the software of Lucidshape. Compared with the traditional compound ellipsoid, the result which comes from variable ellipsoid system demonstrates that the utilization ratio has improves more or less 10%. And the beam pattern in horizontal and vertical direction can match the dipped beam regulation which is "broad horizontal and narrow vertical".