Motor vehicle headlights

Claim 1

A dipped-beam headlight for a motor vehicle, which headlight comprises a reflector, a lighT source disposed at or near the focus of the said reflector, and a device adapted to intercept at least a major portion of that part of the beam of light emitted by the said source which would be directed upwardly by the said reflector in the absence of said device, said reflector comprising, first and second parts, said first part comprising a dome-shaped segment whose surface is a surface of an elongate ellipsoid of revolution, this domeshaped segment defining a rear part of the reflector, said second part comprising a forward part, connected to said rear part along the forward circumference of said segment, this forward part including ellipsoidal surfaces, distinct from the surface of said ellipsoid of revolution, which ellipsoidal surfaces define the forward portion of the reflector, the assembly being such that the section of the ellipsoidal surfaces through the plane containing the major axis of said ellipsoid of revolution contains two elliptical arcs, each of which has a first focus which coincides with the first focus of the ellipsoid and a second focus situated on the straight line joining the second focus of the ellipsoid to the junction point of the corresponding elliptical arc with the elliptical arc constituting the section of the said dome-shaped segment through the plane containing the major axis of the ellipsoid, wherein a deformation has been imparted to the dome-shaped segments such that it has the form of an oval the major axis of which is horizontal, this major axis being greater than the initial diameter of the circumference by about 0,05 times the initial radius of said circumference, and that said device has the form of a screen-cup situated under the light source, said reflector being such that the rear and forward parts form two distinct elements and that the first focus of said ellipsoid is situated inside the dome-shaped segment, said second focus of this ellipsoid being situated outside the reflector, the second focus of said elliptical arc being situated inside the straight line segment connecting the second focus of the ellipsoid to the junction point, this second focus of the elliptical arc being distinct from the second focus of the ellipsoid and being situated outside the reflector, said headlight including a mask disposed forwardly of the said reflector so that the mask, at least partially masks for the driver of an on-coming vehicle the upper part of the reflector.