When we talk about lighting, very often we are speaking about performance, intelligent lighting, communication, size, and design. This is natural, as these characteristics are central to the main safety and style functions of car lights as directly seen by the final customers. But to achieve these results, a lot of hidden work is done upstream, especially with the materials integrated for the realisation of lighting systems.
A great big variety of material is required to build today’s advanced lighting systems, unlike past lamps made of glass and steel, glass and a single type of plastic, one type of polycarbonate and one type of plastic, or even just glass alone in the case of the sealed beam headlamp. Plastics have now supplanted many other materials—we have polypropylene and ABS and PEI for lamp housings, thermoset or polycarbonate for reflectors, polycarbonate and PMMA for lenses, and so on. A long evolution, sometimes needing changes to the regulations, was necessary to go from yesterday’s thick and heavy glass and steel lamps to today’s thinner, lighter, and more variously styled products.
This evolution is far from finished. As rules are becoming more and more restrictive for CO2 emissions, weight is again a decisive factor. In their last report in 2018, the European Federation for Transport and Environment estimated that each increase of 12.4 kg in a car means another 1 g/km of CO2. Each additional g/km of CO2 is becoming so expensive for car makers that new solutions to decrease the weight of parts, including lighting systems, is urgently required. And so the materials industry steps up to help set makers and car makers achieve their lightweighting targets.
But plastic material are not the only ones used. Heat sinks for LEDs are often made of aluminium or magnesium; glass and silicones are often used for the most advanced matrix beams’ primary optics; selectively-permeable membranes are necessary for efficient condensation control, and many other small components and subcomponents contain other-than-plastic materials. And that’s not even to mention the materials used in construction of LEDs, OLEDs, lasers, and other suchlike—those materials are outside the scope of this present report.
After a brief history, this report presents the main materials used currently in vehicle lighting with their main properties. It describes the material needs for the main parts of lighting systems, and the technical and economic benefits and drawbacks for the various material choices. For each type of material, main suppliers are outlined; some of them are more comprehensively presented in the last chapter, and there are interviews with managers.
So, we wish you an enjoyable and informative reading of this report. It may be a bit on the long side, but it’s packed with information usually not readily available about materials for vehicle lighting.