The invention concerns an optical measurement arrangement, in particular for the examination of layer systems, and can include an illumination device having at least one illumination source for delivering a measurement light beam and coupling the measurement light beam into the beam path of a layer thickness measuring instrument. In such a measurement arrangement, the illumination device can be housed in a lamp housing that may be detachably connected to the remaining portion of the measurement arrangement via an installation element wherein illumination sources can be prealigned with respect to the beam path.