Traceable optical coordinate metrology applications for the micro range

Optical sensors are gaining increasing importance in the field of coordinate metrology. Especially for micro range measurements, different optical sensor principles (e.g. white-light interferometers, autofocus sensors, and confocal microscopes) are used. Micro measurement covers the detection and evaluation of measurands for length, size and form of geometrical structures in the range between 1 μm and 1 mm. These reduced dimensions lead to increased requirements for the applied measuring technique and the verification of the measurement systems. The Physikalisch- Technische Bundesanstalt (PTB) works intensively on the development of suitable measurement standards and test procedures to make a broader industrial use of CMMs with optical sensors possible. The test procedures are analogue to the well-established tests for classical coordinate measuring machines (CMMs). For this purpose, adequate and miniaturized reference standards were manufactured, calibrated and tested considering the specific characteristics of optical sensors. This paper gives a summary of this work. Advice on future developments is given.