Optical precision filters with the new EOSS® sputtering system
High-precision optical filters consist of a large number of vertically stacked coatings which either allow certain spectral ranges of the light to pass through or reflect them. They are key elements in many commercial applications, such as, for example, optical instruments. medical technology or high-precision optical analysis. As the performance of the optical systems increases so too do requirements as regards precision, homogeneity of the coating and reproducibility. With the new EOSS® sputtering system developed by the Fraunhofer IST it is now possible to deposit high-precision, almost flawless lenses with long-term stability, doing so reproducibly and at a high throughput.
Here, the coatings are applied to the substrate by magnetron sputtering from up to three sources. This is the first time worldwide that cylindrical sputtering cathodes have been used in a precision lens production installation. Here constantly high levels of coating uniformity can be guaranteed over extremely long periods of operation. Furthermore, the coatings, which are applied by the cathodes in combination with an upwardly directed deposition, are very clean and do not become contaminated even after lengthy coating times. Even in the case of complex optical filters with way over a hundred layers the highest precision, process reliability and fully-automatic production are guaranteed by an optical UV-VIS-NIR broadband monitoring system using MOCCA® process control software.
Micro abrasive pencils with diamond coating enable precise processing
Grinding, drilling, milling, polishing – there are many ways to process glass and yet the requirements for the glass processing industry are increasing. Questions such as "How to get the smallest possible or even micro holes precisely into glass components" or "Which tool can work a micro structure into glass?" are no longer uncommon.
The Fraunhofer IST has now developed a unique solution: Micro abrasive pencils with a diamond coating with smallest diameters up to 50 μm. The special feature of the micro abrasive pencils manufactured at Fraunhofer IST is the closed compeDIA® diamond coating, deposited on the tools. This layer has a sharp-edged roughness, as a result of which it is very useful for the grinding treatment of e.g. glass. Due to the even layer thickness it is furthermore possible to process the workpieces with very high precision.
Glass processing by laser plasma combination and cold plasma spraying
Processing of glass can be very time and energy consuming. Thus, the further development of new different methods for glass processing is constantly taking place at the Application Center for Plasma and Photonics of the Fraunhofer Institute for Surface Engineering and Thins Films IST. Examples are optical components, made of glass equipped with microstructures used in cellphones, high-quality cameras or electronic driver assistance systems. As a rule, laser technology is used to insert the extremely fine structures into the glass surface. The innovative laser plasma hybrid technology developed at the Application Center combines laser technology with plasma technology. This combination strengthens the effect of the laser significantly and reduces the overall energy consumption. Further advantages are an increasing precision of the results, lower production costs and shorter treatment times as well as a simple integration of the plasma source in existing processes.
Another process developed at the Application Center of the Fraunhofer IST is the so called cold plasma spraying. Thereby comparatively small particles – mostly micro particles smaller than 20 µm – are melted by plasma within a plasma jet and sprayed on the substrate. The advantage of using particularly small particles is that the whole process can run at comparatively low temperature. This enables to coat also three dimensional objects from heat-sensitive materials such as paper, plastics or thinnest glass quickly and structured.
As an innovative R&D partner the Fraunhofer Institute for Surface Engineering and Thin Films IST offers complete solutions in surface engineering which are developed in cooperation with customers from industry and research. The IST’s “product” is the surface, optimized by modification, patterning, and/or coating for applications in the business units mechanical engineering, tools and automotive technology, aerospace, energy and electronics, optics, and also life science and ecology.
The principle technology units at the IST are atmospheric pressure processes with the main focus on electrochemical processes and atmospheric pressure plasmas processes, low pressure plasma processes with the main focus on magnetron sputtering and highly ionized plasmas and PECVD as well as chemical vapor deposition with the main focus on hot-wire CVD. The center of tribological coatings focusses on the friction reduction, wear and corrosion protection. The Application Center for Plasma and Photonics deals with mobile plasma sources and laser plasma hybrid processes.
The IST’s expertise lies in the ability to control all of the above-mentioned processes and their combination with a great variety of thin films. Extensive experience with thin-film deposition and film applications is complemented by excellent capabilities in surface analysis using the very latest equipment and in simulating vacuum-based processes.
Choosing the optimum combination of process and coating for a particular task is one of the major strengths of the Fraunhofer IST. Besides fundamental research activities in cooperation with universities and research centers, about 120 employees are developing tailored surfaces and processes together with service providers, equipment manufacturers, and coating users from diverse industries. For an efficient technology transfer the IST offers a broad range of services, from development of prototypes and economical product scenarios to upscaling and even implementation of the technology at the customer.