Optical unit for motor vehicle headlamp - uses plastics reflector with thin plastics zone having reinforcing spines to increase heat dissipation and reduce reflector distortion

摘要

The unit has a transparent front glass (6) covering the rectangular opening of a reflector (7). The reflector has a hole (7A) at the rear for insertion of a filament lamp bulb (8), and an upper, flat topped surface (7 sub 6) in the region above the bulb. The reflector, in the region directly above the bulb, is manufactured with zones of differing thickness plastic (7 sub 6) in order to minimise the risk of distortion and deterioration due to heating of the plastic material used for the reflector. To provide structural rigidity an array of parallel ridges are formed in the thin region above the lamp bulb. These ridges also increase the surface area, increasing the heat dissipation from the headlamp exterior.