High-Throughput Microscopy: Piezo drives for 100-percent testing
- High-throughput microscopy systems: Large-surface objects can be microscoped within seconds. For the first time ever, 100-percent microscopic tests are now possible in the industrial environment (Image: Fraunhofer IPT)
- Piezo-based Scanner for Microscope Objectives: Significantly faster response and higher lifetime than motorized Z stages.
For the first time ever, scientists from the Fraunhofer Institute for Production Technology IPT in Aachen have succeeded in achieving 100-percent microscopic testing of large-surface objects. A piezo-based drive system from PI (Physik Instrumente) was decisive for this success.
For example, the new high-throughput process allows microscoping of microwell plates in just seconds. Conventional image recording processes at high magnification were very time consuming so 100-percent testing was not possible and because of this, random testing was the only alternative.
The team of scientists at the IPT had the following idea: The stage moves the object at a constant velocity during image recording instead of the conventional "stop-and-go" method. In addition, they combined the time-optimized scanning process with real-time data handling and image-processing steps. Even CPU-intensive tasks such as the stitching processes run almost without any delay. Individual images can be merged seamlessly into the overall image even while measuring is in progress.
Because the surface topology considerably exceeds the depth of focus of a microscope objective, for example, due to unevenness of injection-molded plastic microwell plates, it is only possible to focus sharply on the surface when the focus is adjusted in a range of approximately 300 µm. A real-time autofocus function is therefore necessary for three-dimensional image recording; the focus must be adjusted dynamically in the direction of the optical axis with high precision. This task is done by a piezo-based objective scanner.