Confocal arrangement for e.g. three-dimensional tooth shape measurement, has telecentric aperture arranged in internal focal plane of objective lenses to limit numerical aperture of lens, facing object, around specific value

摘要

The arrangement has a telecentric aperture (7) and a trifocal diffractive lens (8) both arranged in a common internal focal plane of two objective lenses (6, 9). The diffractive lens outputs light beams exhibiting zero refractive power, negative and positive refractive power, respectively, upon receiving a beam from a light source. The aperture (7) limits numerical aperture of the lens (9), facing an object, around 0.025. An independent claim is also included for a confocal procedure.