Large-area micro structuring system presented at Lasys
Scientists at Fraunhofer IWS have presented a novel compact system for metal micro-structuring at the Lasys material processing trade fair in Stuttgart, Germany from 24-26 June.
The system is able to impart clever functions onto a material by patterning periodic structures onto its surface. This kind of surface structuring has applications in bio-materials, automotive, the fabrication of more efficient organic solar cells, and for anti-counterfeiting. The scientists presented examples of the structuring process at Lasys.
The system applies a direct laser interference patterning (DLIP) technique to create structures with widths ranging from 150nm to 20µm. The technique can generate a large number of topographically complex structures in one process step, which few other lithographic or micro-structuring techniques can achieve. The system can structure areas up to 500 x 500mm at a speed of several square centimetres per second, depending on the material.
The Fraunhofer IWS engineers have collaborated with the Institute for Applied Photo Physics of the Technische Universität Dresden to improve the efficiency of thin-film organic solar cells with this DLIP structuring. The engineers generated a grid structure on PET substrates, which, once coated with an electrode and an active organic material, improved the performance of the solar cells.
The direct laser interference patterning technology enables the fabrication of 2-, 2.5- and 3-dimensional micro structures on surfaces of both simple and complex compound geometries. To generate the interference structure two or three coherent laser beams of a pulsed laser overlap on the surface. In this way, electric, chemical and mechanical properties of polymer surfaces, metals, ceramics and single-/multi-layers can be periodically varied.
The IWS system can also generate holographic structures directly on metal through local variation of structure widths. This can be used for anti-counterfeiting, for instance.