Previous Page
Researchers at the Fraunhofer Institute for Mechanics of Materials IWM in Freiburg are working on a new process that will make infrared lenses – a component of thermal cameras – up to 70 percent cheaper.
"We have developed a production process for lenses that enables us to lower the costs of these components by more than 70 percent. Thus the prize for the micro-bolometer could be reduced," says Dr. Helen Müller, scientist at IWM. Normally, the lenses are made out of crystalline materials like germanium, zinc selenide or zinc sulfide. The problem is that these materials are very expensive and can only be processed mechanically – it takes grinding, polishing or diamond turning to shape them into the correctly. Obviously this involves high processing costs. "Instead of crystalline materials, we use the amorphous chalcogenide glass. Its softening temperature – that is, the temperature at which it can be formed – is low. Therefore, we can form it using non-isothermic hot stamping," says Müller. This process is similar to making waffles on a waffle iron.
The researchers place the chalcogenide glass between two pressing tools which determine the form of the required lenses. Then, it is heated and for- med between both pressing tools – the "waffle iron" is clamped together. After a few minutes, the glass is cooled again to below the softening temperature and removed. And thus, the lens is already perfect. In contrast to conventionally processed optics, it no longer has to be further refined. The lenses manufactured this way exhibit the same excellent optical imaging quality as those that are polished. To ensure that no glass remains attached to the tools, their surface is coated with anti-adhesive, non-stick coatings, similar to the Teflon coating on a waffle iron. The scientists now want to further refine the process towards cost-effective mass production.
The results from Florida State University and the National Science Foundation-supported National High Magnetic Field Laboratory, or MagLab, in Tallahassee, Fla., USA, shed fundamental light on the self-assembly of carbon networks. The findings should have important implications for carbon nanotechnology and provide insight into the origin of space fullerenes, which are found throughout the universe. Despite worldwide investigation since the 1985 discovery of C60, buckminsterfullerene and other, non-spherical C60 molecules – known collectively as fullerenes – have kept their secrets. How? They‘re born under highly energetic conditions and grow ultra-fast, making them difficult to analyze. "The difficulty with fullerene formation is that the process is literally over in a flash – it’s next to impossible to see how the magic trick of their growth was performed," said Paul Dunk, a doctoral student in chemistry and biochemistry at Florida State and lead author of the work.
Paul W. Dunk, Nathan K. Kaiser, Christopher L. Hendrickson, John P. Quinn, Christopher P. Ewels, Yusuke Nakanishi, Yuki Sasaki, Hisanori Shinohara, Alan G. Marshall & Harold W. Kroto: Closed network growth of fullerenes, In: Nature Communications, Vol. 3, Article number 855, May 22, 2012, DOI:10.1038/ncomms1853: http://dx.doi.org/10.1038/ncomms1853