Interferometric short coherent shape measuring device for valve seat surfaces has beam splitter to form object beam guided over optical path to object and reference beam guided to reference plane

摘要

The interferometric measuring device measures the shape of a surface of an object using a radiation source (KL) which outputs short coherent radiation. The device has a beam splitter (ST) to form an object beam guided over an optical path (OW) to the object (BO) and a reference beam guided to a reference plane via a reference optical path (RW). The device also has an image converter (BW) which takes in the radiation reflected from the object surface and the reference plane which has undergone interference and supplies it to an analyzer for determining a measurement result relating to the surface (A). For the measurement, the optical length of the object optical path (OW) is varied relative to that of the reference optical path. In the optical path is a superposition lens with a multi focal lens or a free segment lens of different imaging elements. The superposition lens generates an image of the surface and also of another surface which is imaged directly or via an intermediate imaging on the converter. The surfaces are measured by relative changes in the optical lengths of the optical and reference paths.