Patent ID: 8913247

Claim:
A device for interferometric vibration measurement on an object, comprising: a radiation source for generating an original beam, a first beam splitter for dividing the original beam into a measuring beam and a reference beam, a detector and a focusing device, the device is implemented in such a way that the measuring beam at least partly reflected by the object and the reference beam are superimposed on a detection area of a detector, the focusing device is arranged in the beam path of the measuring beam, for focusing the measuring beam onto a measuring point on the object, the device is adapted to generate a measuring beam having a wavelength greater than 1100 nm, an image unit that provides a two-dimensional non-interferometric imaging of at least a sub-region of the object surrounding the measuring point, the focusing device is arranged in the beam path between image unit and the object, a focus of the measuring beam lies approximately in a focal plane of the image unit, and the focal point of the measuring beam and the focal plane of the image unit are displaceable simultaneously by the focusing device, a second beam splitter arranged in the beam path of the measuring beam between the focusing device and the detector and in the beam path of the image unit between the focusing device and the image unit that is constructed such that a loss of intensity of radiation in the visible range between focusing device and the image device is less than 50% so that the second beam splitter is transparent for light in the visible range in the beam path between the focusing device and the detector, and a loss of intensity of the measuring beam between the focusing device and the detection area of the detector is less than 50%, and an optical lens arranged in the beam path of the measuring beam to produce a virtual focus in respect of the measuring beam, said focus being imaged by the focusing device onto the measuring point of the object.