Ultra-thin glass is often called the new miracle material for a wide variety of applications in optics, biotechnology and the semiconductor industries. At less than 0.2 mm “thick,” it appears to be as thin as polymer film yet has surface properties compared to plastic and metal films, such as particularly high smoothness, scratch-resistance and transparency.
This makes the material desirable for smart-touch surfaces and displays in consumer electronics and the automotive sector. Mass production of optical components requires materials that can serve as the basis substrate for the individual components. In addition, these kinds of sensitive optical systems must be able to be encapsulated to protect them from environmental influences.
The trend towards ever thinner, more flexible and powerful yet lighter electronic devices and automobiles of the future is increasingly leading now to a shift in the glass thicknesses sold in mass volumes to even considerably below 0.2 mm.
Although it is currently feasible to manufacture glass in a thickness range of below 0.1 mm – which will be important in the future – it is not always possible to achieve the required specifications. The challenge in using such thin glass also lies in the entire process chain for its subsequent processing. There is currently no processing plant technology available at all that can be converted for implementing these process steps.
This is where the BMBF-funded GLASS4FLEX joint research project comes in, launched April 1, 2019. The joint project intends to develop new process technologies that do not exist yet as the pioneers for flexible glass applications in next-generation optical systems, and to establish them for developers of such optical systems.
The SCHOTT company, active in development as well as being a manufacturer of ultra-thin glass, stands at the core of the consortium. The project's participants span the entire process chain – starting with the SCHMID Group, which will be involved with the development of cleaning processes and the associated process technology for thin glass using in-line cleaning systems. The imaging and signal-processing firm Gesellschaft für Bild- und Signalverarbeitung GBS mbH will then take over the R&D for the analysis of the surface properties including the measurement system engineering.
The project addresses the handling of flexible individual large-area thin glass with a maximum size of 1.2 m × 0.6 m, where solving handling problems will be one of the greatest challenges in the project.
The partners ProTec Carrier Systems GmbH and Adenso Industrial Services GmbH meet the challenge. The former – a specialist in developing secure mounting systems – will develop these for the thin glass fixation during the vacuum coating process. Adenso Industrial Services GmbH is engaged in transfer technologies for thin glass before and after vacuum coating. As part of the GLASS4FLEX project, the Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP, in Dresden, Germany, will conduct research on functional optical and electrical coatings for this thin glass in sheet-to-sheet processes based on its state-of-the-art expertise.
“We want to work hand-in-hand with all six project partners to develop new process technologies for the production of high-strength thin glass that can withstand full mechanical stress despite its low thickness,” said project coordinator Dr. Manuela Junghähnel of Fraunhofer FEP. “The development of safe cleaning and defect inspection of these types of glass are integral to this, as are the mounting system and functional coating.”
The result should be the presentation by 2022 in Dresden of the first coated large-area thin glass with color-neutral scratch protection and a transparent electrode, made with a fully developed process chain.
The Fraunhofer FEP has been conducting research in coating technologies for ultra-thin glass for several years. Outstanding results have already been achieved in the development of roll-to-roll technologies for depositing inorganic materials on flexible glass.