The development of highly complex microlens arrays via the natural way and with remarkably simple components: Chemists of the University of Konstanz and the Max-Planck-Institute of Colloids and Interfaces have developed a process which highly simplifies the production of microlens arrays. Based on calcium carbonate (chalk), the researchers generate naturally grown surface layers with an ordered position of micrometer sized half spherical chalk lenses.
So far, micro lens arrays could only be generated with a sophisticated lithographic process on basis of plastics. The development of the new synthesis process was achieved in cooperation with the Korea Institute of Geoscience and Mineral Resources and the South Korean university KAIST.
For the generation of the optically fully functional microlens arrays, the researchers exclusively need a saturated calcium solution, carbon dioxide from air and a broadly available surfactant (a soap molecule), which regulates the formation of the microlens structure. The process is by far more cost effective and simple than existing production methods. „It is remarkable that structure formation occurs by itself in water at room temperature – completely similar to the archetype Nature. This is an example for the successful application of biological principles for the generation of advanced optical elements completely without use of energy or toxic chemicals“, summarises Konstanz chemist Prof. Dr. Helmut Cölfen the advantages. The new process in which the micro lens arrays equally “grow” in a natural way was developed starting from a natural archetype: The so-called brittlestar, a relative of the starfish, uses a chalk microlens array on its skin to change colour according to the lighting conditions.
A microlens array is an optical field with a large number of micrometer sized miniature lenses placed closely together. Microlens arrays are applied for miniaturisation of optical systems, focussing of light with a precision of a millionth meter and to work with very small wavelengths. Amongst other applications, microlens arrays are applied for cell phone cameras but also in medical technology. The new process is also suitable to generate anti-reflex coatings, which are for example known from eyeglasses. Further advantages of the new method are that the chalk lens systems have shorter focal lengths compared to the so far exisiting plastic lens arrays and that the lens systems can be transferred to other surfaces by a simple dip coating. Furthermore, living cells like the microlens surface which enables future biomedical research combined with optics.
„It is truly remarkable how simple the generation of the microlens arrays is: All applied materials are common and biocompatible chemicals, energy supply is not necessary. The reaction takes place at room temperature in water according to a principle which Nature uses for Biominerals“, explains Helmut Cölfen. „Beside all these technical advantages, the amazing fact that such highly complex structures like a microlens array can be generated using comparatively simple molecules makes this process highly interesting for the scientist“, Cölfen outlines further perspectives for science.http://www.pi.uni-konstanz.de/2012/031.jpg
Seeing the quantum future... literally
16.01.2017 | University of Sydney
Airborne thermometer to measure Arctic temperatures
11.01.2017 | Moscow Institute of Physics and Technology
Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.
As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...
At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).
Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...
Many pathogens use certain sugar compounds from their host to help conceal themselves against the immune system. Scientists at the University of Bonn have now, in cooperation with researchers at the University of York in the United Kingdom, analyzed the dynamics of a bacterial molecule that is involved in this process. They demonstrate that the protein grabs onto the sugar molecule with a Pac Man-like chewing motion and holds it until it can be used. Their results could help design therapeutics that could make the protein poorer at grabbing and holding and hence compromise the pathogen in the host. The study has now been published in “Biophysical Journal”.
The cells of the mouth, nose and intestinal mucosa produce large quantities of a chemical called sialic acid. Many bacteria possess a special transport system...
UMD, NOAA collaboration demonstrates suitability of in-orbit datasets for weather satellite calibration
"Traffic and weather, together on the hour!" blasts your local radio station, while your smartphone knows the weather halfway across the world. A network of...
Fiber-reinforced plastics (FRP) are frequently used in the aeronautic and automobile industry. However, the repair of workpieces made of these composite materials is often less profitable than exchanging the part. In order to increase the lifetime of FRP parts and to make them more eco-efficient, the Laser Zentrum Hannover e.V. (LZH) and the Apodius GmbH want to combine a new measuring device for fiber layer orientation with an innovative laser-based repair process.
Defects in FRP pieces may be production or operation-related. Whether or not repair is cost-effective depends on the geometry of the defective area, the tools...
10.01.2017 | Event News
09.01.2017 | Event News
05.01.2017 | Event News
16.01.2017 | Power and Electrical Engineering
16.01.2017 | Information Technology
16.01.2017 | Power and Electrical Engineering