LIPPSTADT, Germany—Liquid silicone rubber is a new player in automotive headlamps. The story of how it got there really started a couple of years ago. Back to a presentation at the VDI Association of German Engineers' Plastics in Automotive Engineering Congress in Mannheim, Germany, in March 2015.
At that meeting, Tilman Maucher, lighting development project manager at automotive lighting producer Hella KgaA Hueck & Co. in Lippstadt, Germany, showed how polymethylmethacrylate (PMMA) and polycarbonate (PC) were being used as amorphous thermoplastic materials for injection molded headlamp lenses.
Replacing glass with thermoplastics resulted in less weight, greater functional integration and lower cost.
While heat within headlamps had been rising as designers moved toward lower-profile headlamps, introduction of high-power LED light sources meant that there was less heat going forward toward the front of the headlamp compared to more traditional halogen or xenon HID lamps.
Less heat going forward meant more opportunities for thermoplastic lenses. Maucher said the first plastic lens approval was in 1993, on a path leading to Hella's first full-LED headlamp, with a polycarbonate secondary lens used in series production on the Cadillac Escalde Platinum in 2008. A plastic secondary lens was used less than two years later on the Audi A8.
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