During this project a new technology for the 3D-inspection of small parts following the principle of confocal imaging was built up and analysed. The key part was a Digital Micromirror Device (DMDTM), consisting of 864x576 programmable mirrors. Each of these has dimensions of approx. 13 x 13µm2 and can be set to an angle either -10 or +10 . So, every mirror element of the DMD inherently represents a pinhole. One DMD can be divided into two sub-arrays of micromirrors, that can be combined to obtain one confocal measurement system itself. The first is used as the illumination part, the second as the detecting part. Thus, using the whole aperture of the DMD, an amount of some ten confocal systems can work in parallel. This new approach does not scan the specimen using only one point as current systems do, as it allows scanning with some ten to hundred points.
The following specifications were reached during the project:
- measurement duration: in the range of seconds
- measurement volume: ranging from 10 x 10 x 5mm3 to 10 x 10 x 5µm3
- accuracy: ranging from 0,1µm to 10nm depending on the measurement volume