Device for inspecting workpiece surfaces and strip materials

A device for the inspection of a workpiece surface or a strip material, comprising:

• at least one sensor;
• at least one sonotrode having a sound-emitting surface and connected mechanically rigidly to the sensor to form a sensor unit;
• and
• a movable positioning device coupled with the sensor unit and configured to position the sensor unit in a position opposite to the workpiece surface or a surface of the strip material, said positioning device including a force-applying member to urge the sensor unit in a direction of the workpiece or strip material surface by applying a predefined urging force or using gravity as the urging force,
• said sound-emitting surface of the sonotrode generating ultrasonic oscillations to produce an ultrasonic levitation force field in the presence of a gaseous medium between the workpiece or strip material surface and the sound-emitting surface to thereby generate a counterforce in opposition to the urging force so that the sensor unit is held hovering at a distance to the workpiece or strip surface.