Imaging optics like telecentric lenses are usually not only measured on axis, but also at field points. In addition to the imaging quality (transmitted wavefront and PSF/MTF), information about focal length, image field curvature or chromatic effects is also of interest in R&D and production applications.
Compared to classic MTF measurements, knowledge of the wave aberrations and the corresponding Zernike decomposition facilitates the identification of possible causes of errors, and provides considerably better options for comparison with simulation data.
The transmitted wavefront is measured within milliseconds and provides precise information about the individual wave aberrations of a lens. Since the wavefront is reconstructed from a single camera image, the Shack-Hartmann method is fast and offers a high level of intrinsic stability. Shack-Hartmann wavefront sensors are therefore also used for inline inspection tasks. For example, focus-variable lenses with different refractive powers can be efficiently measured in the tray.
Our solution for machine vision applications
Lens measurement stations and modules of the SHSInspect family measure the transmitted wavefront, PSF and MTF. Moreover, they provide information on chromatic effects, focal length and polarization effects and enable measurements at field points.
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