Paraboloid Headlights
In the paraboloid headlights the reflector surface forms a paraboloid, i.e. a parabola turned around its axis, see figure, in such a way that the light radiated upward is reflected downward by the reflector, about the Z-axis, onto the road. Hence the light is almost parallel up to the point of divergence of the light beam and depending on the size and position of the filament of the lamp. In the headlight low beam a screen ensures the fact that light is radiated only from the upper half of the reflector thus preventing a dazzle to the oncoming traffic. The paraboloid headlight operates on the principle of reflection.
Optical elements in the headlight glass cause the distribution of the light, so as to fulfill the legal demands. Cylindrically shaped profiles that are placed perpendicularly cause a horizontal distribution of the light. Prismatic structures located higher in the optical axis disperse the light upwards.
With an increasing size of the reflector the effect of the headlight low beam improves. A construction that is as large as possible results in a large geometric range, but this is however not always possible due to aerodynamic reasons.