A heat-conducting Arnite XL-T grade from DSM Engineering Plastics based on a thermoplastic polyester has found commercial application in an LED/HID (high-intensity discharge) lamp lighting module used in the new Audi Q7's headlight. The superior performance of the grade, with a heat deflection temperature (HDT) of 250°C, low outgassing and excellent textured surface finish in dark colors reportedly offer designers and engineers extended freedom in headlight LED lamp module construction.
Headlights are a key distinguishing feature for a car's identity and currently LED lighting, with its excellent performance characteristics, is the cutting edge of automotive headlamp design. They are also a safety critical item and must perform to the highest international standards. LED, HID lamp and halogen lighting systems, often combined in one headlight assembly, offer excellent performance but also place more restrictions on the use of materials and design. Further, sunlight radiated into the multiple LED/HID lenses creates localized increases in thermal loadings in excess of 235°C.