Low Beam Head Lamp Design Using Distributive Lighting System

Distributive lighting systems utilizing high intensity discharge (HID) light sources and optical fiber light pipes are capable of delivering a large luminous flux to head lamp assemblies. The challenge is to design an efficient lamp package that angularly distributes this flux to meet legal and customer requirements for head lamp photometry performance. In this communication we: 1) review photometry guidelines which make the design of die low beam lamp package challenging, 2) outline the basic relationships between the optical design parameters, 3) illustrate solutions to the design optimization problem with three low beam head lamp design approaches, and 4) present photometry results and a computer rendered road simulation for prototype distributive lighting low beam head lamp hardware. These results show that the prototype hardware passes all SAE photometry test points and projects approximately 50% more luminous flux into the beam pattern region than a typical sealed beam or composite tungsten-halogen head lamp with 35% less total power consumption.