FR2500583A1 - VEHICLE PROJECTOR - Google Patents

Abstract

VEHICLE HEADLIGHT INCLUDING A THERMOFORMABLE PLASTIC REFLECTOR, SURROUNDING THE LIGHT SOURCE. PART 5 OF THE PLASTIC REFLECTOR 1 LOCATED AT THE APLOMB OF THE LIGHT SOURCE 6 IS DECOUPLETED FROM THE NEIGHBORING PARTS OF THE WALL WITH RESPECT TO THE WARPING FORCES PRODUCED BY THERMAL EXPANSION.

Description

The present invention relates to a vehicle headlamp with a

  thermoformable plastic reflector, surrounding

the light source.

  When the projector is on, the hottest point of the reflector is in the area directly above the spiral filament light source. The neighboring parts

  colder reflectors counter the strong thermal expansions

  produced in this hot part and thus limit them to

  ably. The resulting warping forces generally produce a deformation of the reflector such that the displacement of the light-brown boundary of the dipped headlamp becomes inadmissible

  and that the light distribution is furthermore substantially disturbed.

  The invention relates to a plastic reflector whose part located at the amplomb of the light source does not deform when the projector is on, or has a non-reactive deformation

  on the other parts of the reflector. According to an essential characteristic

  of the invention, the part of the plastic reflector situated at the amplomb of the light source is decoupled from the adjacent parts of the wall with respect to the warping forces produced by

  thermal expansion. Such decoupling of this relative part

  small reduction significantly reduces the warping forces

by the limitation of dilatation.

  According to another advantageous characteristic of the invention, the plastic reflector has an opening in the part located

  the amplomb of the light source. This embodiment is useful

  readable in the case of a reflector protected by a body against

external influences.

  According to another advantageous characteristic of the invention, the

  Verture is covered by a hydrophobic material. The external surface

  of such a reflector may be directly subject to external influences.

  According to another advantageous characteristic of the invention, the

  verture is in the form of an arcuate but non-annular slot

  and closed; and the width of the slot is at least equal to the dilat-

  produced at this location. The interior of the reflector is thus relatively well protected against the penetration of liquid and dust. According to another advantageous characteristic of the invention, the thickness of the portion of the plastic reflector located directly above the light source is reduced compared to that of the parts

  neighbors, and thus presents itself as a membrane. A strong reduction

  The thickness of the reflector wall in this part significantly reduces the warping forces produced by the large thermal expansion. The reflector, waterproof even in this part,

  also allows economical production.

  According to another characteristic of the invention, the diameter of the decoupled surface portion of the plastic reflector is between 0.5 and 0.2 times the distance between the light source and the

  wall of the reflector located at its right.

  Other features and advantages of the invention will be

  better understood using the detailed description below of two

  embodiments and the accompanying drawing in which Figure 1 is a longitudinal section of a plastic reflector whose wall has a portion of reduced thickness; Figure 2 is a partial view of the plastic reflector along the arrow X; and

  FIG. 3 is the partial plan of a reflector comprising an opening

ture shaped slit.

  FIG. 1 represents a plastic reflector 1 in the neck 2 of which an incandescent lamp 3 is mounted. Upper flats

  4 and lower 4a give the plastic reflector 1 a rectangular shape.

  gully in the direction of light.

  In FIGS. 1 and 2, the upper flat part 4 is decoupled in a part S situated directly above the light source 6, the parts close to the wall by a reduced thickness, with respect to the warping forces produced by the thermal expansion. when

the projector is on.

  In FIG. 3, the portion 5 of the plastic reflector 1 located vertically above the light source 6 is decoupled by an opening 7

  of the upper flat 4 with respect to the warping forces

  when the projector is turned on. The opening 7 is in the form of an arcuate slot, non-annular and closed. The tongue thus produced covers the inside of the reflector. Of course, various modifications may be made by those skilled in the art to the principle and to the devices which have just been described as non-limiting examples,

  without departing from the scope of the invention.

Claims (6)

claims   1. A vehicle headlamp with a thermoformable plastic reflector surrounding the light source, said headlamp characterized in that the portion (5 and Sa, 7) of the plastic reflector (1) located at the end of the light source ( 6) is decoupled from the neighboring parts of the wall with respect to the forces   warping caused by thermal expansion.   2. Projector according to claim 1, characterized in that the plastic reflector (1) is open in the part located & amplomb of the light source (6).   3. Projector according to claim 2, characterized in that the   Verture is covered by a hydrophobic material.   4. Projector according to claim 2, characterized in that the   verture is in the form of an arcuate slot (7), but not annular and closed; and the width of the slot is at least equal to   the thermal expansion produced at this location.   5. Reflector according to claim 1, characterized in that the thick-   of the part (5) of the plastic reflector (1) situated directly above the light source (6) is reduced compared to that of the neighboring parts.   6. Reflector according to any one of claims 1 to 5, characterized   characterized in that the diameter of the uncoupled surface portion (5, 5a) of the plastic reflector (1) is between 0.5 and 0.2   the distance from the light source (6) to the wall of the reflec- located at his feet.