The chemical company is developing tailored materials that correspond to the specific requirements of various LED applications. In doing so, it is closely collaborating with all partners in the development chain for LEDs as a sustainable lighting source of the future, said Klaus Reinartz, head of the global LED program at Bayer MaterialScience. “Our focus is on both a wide variety of injection molding and extrusion granules, such as for optical lenses, and semi-finished film and sheet products for the production of such things as light diffusers and reflectors.”
The latest examples for the company's development expertise are polycarbonates with particularly high thermal conductivity for cooling elements used for the thermal management of LEDs and a film that joins the points of light from individual LEDs to form a homogenous band of light.
Compared with glass and metal, polycarbonate offers greater design freedom in the design of LED components, which are frequently very small and geometrically complex. Furthermore, it is significantly lighter. For these reasons, it is used for the injection molding of such things as LED lenses for the low-beams and tail lights as well as light guides for the daytime running lights in automotive headlamps. Compared with other transparent plastics such as PMMA (polymethyl methacrylate), polycarbonate is more impact-resistant and thus more resistant to breakage in addition to being much more resistant to heat. It can be used at temperatures up to 120 °C. Its high refractive index allows optical components to be very thin, which is particularly beneficial for the injection molding of LED lenses.
The new polycarbonates for LED cooling elements, such as Makrolon TC 8030, are an alternative to aluminum. “These allow the cooling ribs to be more delicate and lighter. Unlike their aluminum counterparts, the injection-molded cooling elements require no post-treatment, enabling cost-effective production with low energy consumption,” said Reinartz.
Sheets and films of polycarbonate also have strong potential for applications in LED lighting,