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A headlamp reflector has many performance requirements. Principal among these is the need to deliver a compliant beam pattern while withstanding a severe heat environment. In serving this requirement, the reflector must reliably secure the light source (bulb filament) relative to the optical prescription (facets) of the reflector. Traditionally, achieving this performance requirement has been challenging since the reflector elements which are designed to deliver stable and reliable optical performance, are the same elements which must also withstand thermal stresses and adjustment-related static stresses within the reflector. The integrity of these optical elements may also be limited by surface sink, especially in the bulb fastening and attachment locations. The current work describes the design of a reflector bracket through which these forces can be minimized and accommodated while delivering robust optical performance.

This paper examines a variety of thermocouple and infrared measurement techniques as means of obtaining accurate and consistent temperature measurements within a headlamp system. While measuring temperature is straightforward in principle, in practice, these measurements are fraught with potential error. The paper summarizes a succession of experiments conducted at our Parts Design Center (formerly the Application Development Resource Center) in Pittsfield, MA. These experiments lead to the ability to accurately measure temperature at a given location within a lamp assembly. Using these studies and the resulting transfer functions as a foundation, a Design of Experiment (D.O.E.) is presented which explores the effect of a variety of headlamp design factors on the surface temperature of a headlamp reflector at a given location.

This paper will discuss the analysis of a high-heat, unfilled polyetherimide (PEI) thermoplastic in a complex reflector application with conventional aim (bubble-vial) beam pattern. The advantages and disadvantages of using PEI thermoplastic vs. bulk molding compound (BMC) in a complex reflector will be presented. Design features, testing methodology, and processing techniques for the use of PEI in such applications will also be highlighted.