Patent ID: 8913249

Claim:
An optical system for illuminating at least one surface of a measured object, comprising: a beam-generating light source to introduce light beams; a first optical element; a second optical element, wherein the first optical element is for forming at least one first beam path and at least one second beam path, which are situated so that light beams in the at least one first beam path are directed by the second optical element, which is downstream from the first optical element, perpendicularly onto a first object surface; and a third optical element, wherein light beams in the at least one second beam path are directed by the third optical element, which is downstream from the first optical element, onto a second object surface, wherein the at least one first beam path of the light beams which are reflected on the first object surface and the at least one second beam path of the light beams which are reflected on the second object surface at least partially overlap in an area having beam directions which are oriented parallel to one another; wherein a total path difference of both optical path lengths is greater than a coherence length of the light source such that the beams reflected from the first object surface and the second object surface are prevented from interfering with each other.