Towards Improved Halogen Lighting Performance using a Combination of High Luminous Flux Sources and a Lens Material Approach

Currently, automobile manufacturers receive automotive headlamp assemblies from headlamp manufacturers with outer lenses produced of clear or slightly blue tinted polycarbonate. Such headlamp designed to provide optimized light output have very similar aesthetics, and leave little room to differentiate one car platform from another, using the outer lens color. With edge glow technology a car manufacturer can provide an appealing aesthetic look (edge glow effect) from the outer lens. Additionally, this technology can be used to improve the quality of the beam color emitted through the outer lens. Dependent on the chosen combination of halogen source and lens formulation, a range of beam colors spanning from halogen to HID is attainable, where the beam pattern and color continue to conform to the applicable SAE and ECE beam photometry and color standards and regulations. Headlamps manufactured using this technology can produce a lower cost alternative to the more expensive high intensity discharge (HID) lamps in terms of lighting performance while providing more comfort for the driver than regular halogen based systems. This paper details the edge glow headlamp system and reports on the continuation of the work on colored headlamp lens formulations and their performance in automotive applications. New data is provided on the performance of the edge glow headlamp system operated in combination with a selection of light sources spanning an extended range in luminous flux. A case is presented in which HID color is successfully matched using a HIR2 light source in combination with a lens made from active lens materials.