You also develop customized solutions. Which applications or areas do the microdisplays cover in this context? Are there other conceivable options?
Wartenberg: Apart from the aforementioned applications, microdisplays are an essential component of VR/AR and MR glasses. They can also display navigation instructions in bicycle and motorcycle helmets, not to mention their use in industrial applications in the logistics, plant maintenance, and assembly areas. Since these are microchips, we can integrate other functions, such as sensor components. This also makes intelligent microdisplays possible, an example of which is our bi-directional microdisplays. Aside from the display, they also contain a camera function, which makes them attractive for a variety of applications, including medical diagnostics and therapy. Industrial applications are another area, but also security equipment where they double as high-precision optical fingerprint sensors.
Here are a few concrete examples: amid a pandemic, a combination of heat sensor and display technologies can indicate to the nursing staff whether a patient has a fever; the integrated sensors in the bi-directional microdisplay can be used as an eye-tracking system, which helps to overcome physical barriers to communication. In metal welding processes, the technology enables a welder to track the thermal image at a weld seam. All these are examples of the vast potential of microdisplays as near-to-eye applications.
What are the smallest microdisplays in the FEP portfolio and how much smaller can they still get?
Wartenberg: The size of a microdisplay is always based on the respective application and parameters like resolution – meaning the number of pixels a screen can show – and pixel size, which is specified by the optics and CMOS technology. It also plays a role whether it is a monochrome display, meaning it only requires one (sub)pixel, or a colored display, which typically requires a red, green and a blue subpixel. We conduct research from different angles at the Fraunhofer FEP. Apart from the trend towards ever smaller pixel sizes, this also includes research into highly efficient and application-adapted CMOS-integrable light sources, innovative, highly integrated CMOS circuits and system-on-chip (SoC) solutions, and the development of customer and application-specific microdisplays and processes.