Functionalized and curved surfaces made of glass or plastic, rollable displays, high-quality bended surfaces for architecture or interior design in automotive or luxury furniture sector – flexible materials with integrated functionalities are not just a technological trend but capture markets already. Pioneering ideas like fully featured, curved and high-class panels in cars or a touch remote control within the armrest of your design chair are close at hand. All these features could be sealed with haptic comfortable, scratch-resistant and anti-reflective glass.
A fundamental prerequisite for such applications is a suitable and flexible substrate material, which needs to fulfill appropriate characteristics and requirements. Flexible, ultra-thin glass offers the ideal basis for printed-electronic devices. Flexible electronic devices need to be protected against water and oxygen in a reliable way. Glass offers that protection but in certain applications glass may not be used due to technical or regulatory limitations. Especially for those applications and devices flexible barrier films are the solution to be used. Both ultra-thin glass and permeation barrier films require a broad technical know how and particularly adjusted processes and technologies for successful processing and coating.
Fraunhofer FEP is a leading research partner for surface treatment and vacuum coating as well as the deposition of organic electronics on flexible substrates. For many years, we have been extending and improving our expertise especially in the field of roll-to-roll process development and vacuum coating. We use a variety of research and development coating machines at our institute. Since 2015, Fraunhofer FEP is acting as a competence center for flexible glass.
Thanks to the excellent process know-how of our experts and our cooperation partners, ultra-thin glass can now be processed right from the roll. Resulting from this, a full 100-meter roll of flexible glass has been processed with highly conductive ITO completely with R2R technology together with our long-term collaborator Corning Incorporated. These promising results have been achieved on our FOSA LabX 330 Roll-to-Roll Thin Glass Coating line, which was put into operation recently – and they are impressive: the full 100 meters of flexible glass have been coated at a process temperature of 350° C without any defects. “This paves the way for coatings on flexible glass as a substrate, which can directly be implemented into applications”, Dr. Manuela Junghähnel, coordinator of all thin-glass activities at Fraunhofer FEP looks ahead enthusiastically. This coated roll of thin glass from Corning will be presented during the 2017FLEX in Monterey for the first time.
Outstanding progress has been made in large-area roll-to-roll manufacturing technology for barrier films, as well. Dr. John Fahlteich, research group leader at Fraunhofer FEP explains the latest results: "Following an upgrade of the coating line coFlex® 600 we succeeded to produce a functionalized plastic web consisting of a permeation barrier and a transparent electrode with a defect density < 1 cm-2 without operating in a complex and expensive cleanroom environment. The functional film has a surface sheet resistance of < 12 Ω. Such specifications are ideal for the use and integration in flexible OLED sheets or as a substrate for flexible solar cells." Another positive side effect is an increase of the process reliability and high yield in pilot scale. Especially for further applications like high quality packaging foils, membranes and for printed electronics these effects are resulting in a significant cost reduction and increase of the performance.