Indirect optical geometry measurement

ongoing

Optical metrology is driving our society forward and has strong impacts on manufacturing, mobility, medicine and fundamental science. This is highlighted by the SI revision in 2019 and the Nobel Prize winning microscopy with visible light in the nanometre range in 2014. Optical techniques allow fast and precise geometry measurements, but only if sufficient light energy is reflected from the object’s surface to the photo detection unit. For this reason, specific measurement approaches for each surface type had to be developed such as deflectometry for highly reflective surfaces. To provide one single measurement approach applicable to any surface and with the potential of sub-micrometre resolution, InOGeM will initiate a paradigm shift: instead of measuring the object’s surface, the geometry of the surrounding gas is measured. The surrounding gas is detected optically by using tiny, well-controlled, fluorescent particles or molecules, a confocal microscope and a model-based signal processing, which enables sub-micrometre resolution. This will break new grounds for assessing additively manufactured parts and lightweight components made of fibre-reinforced composites, because the indirect measurement is less sensitive regarding the varying optical properties of the measurement object’s surface and material. Furthermore, indirect optical geometry measurements are possible at strongly curved or translucent objects even through a limited access, which is currently considered impossible. Such challenging conditions occur e.g. for gears and additively manufactured parts, so that InOGeM has a large potential for low-noise gears (e-mobility) and fuel cells (hydrogen). As a result, fast geometry measurements with a today unachievable precision below classical limits are achieved in the nanometre range for a wide range of applications. By developing the framework of a new class of measuring instruments, InOGeM takes the field of optical geometry measurements to the next level.