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This paper reviews headlamp developments that have taken place in Europe and particularly in the UK. It outlines the changes which occoured due to the requirement for greater styling and aerodynamic design freedom and resulted in the introduction of headlamps having a rectangular frontal aspect. These headlamp design changes dictated a move away from the twin transverse filament approach of the SAE beam distribution to the more controllable shielded axial filament system used to achieve the ECE beam pattern. The relevence of the UK experience is discussed in view of the changes that have been introduced to permit replaceable bulb headlamps in the USA.

The requirement to reduce the vertical frontal area of motor vehicles to improve aerodynamics and styling has prompted the development of headlamps having narrower vertical apertures. This paper describes the development work which has been carried out jointly by Lucas in England and Carello in Italy with the objective of maintaining the photometric performance achieved by conventional large headlamp systems. Various design possibilities including projector systems and reflector designs employing an unshielded bulb are considered but the Lucas/Carello work has led to the conclusion that the multifaceted reflector offers the greatest advantages. By employing these high efficiency multifaceted reflector forms it can be shown that the performance objective can be achieved from a reflector having a 75 mm vertical aperture.