visual impression of a larger illuminating area either for styling reasons or for the visual comfort of drivers of vehicles travelling in the opposite direction given that the impression of being dazzled is reduced by the presence of the two lateral extensions 50 of the lens which also emit light the plates 50 can be selectively fixed to the intermediate part 30 by any appropriate means in this instance these means comprise ribs in the form of curved blades 34 in one piece with the part 30 and running along the lateral contours of the lens 40 the ribs are glued into complementary grooves on the inside face of the plates 50 near their respective inside edge accordingly in this first embodiment of the invention the same basic components namely the lamp 10 the reflector 20 the intermediate part 30 and the lens 40 can be used to produce either a conventional elliptical headlamp or by adding the plates 50 an elliptical headlamp with an enlarged illuminating area the unit cost of the headlamps remains reasonable and the number of parts to be held on inventory remains limited the plate has on its inside face the prisms 51 described above and con its outside face a regular arrangement of spherical or toroidal balls 52 or equivalent optical components.