Abstract: The invention is directed to a reflectance measuring apparatus for making contactless measurements on structured test objects wherein the measuring result is independent of the distance of the test object within a difference range (d). The illumination arrangement and the measuring arrangement have a common center axis (z) which extends perpendicularly to the surface of the test object. At least the illumination arrangement or the measuring arrangement includes at least three radiation transmitters or three radiation receivers having optical axes arranged on at least one cone (c) concentric with respect to the common center axis (z). Of the set of radiation transmitters and the set of radiation receivers, one of the sets is configured to have a parallel ray bundle with a core area (k) and the other one of the sets is configured to have a bundle having a limited aperture with the area (m) covered by the limited aperture or apertures being smaller than the core area (k) within a distance range (d).

Abstract: The invention is directed to a reflectance measuring apparatus having a predetermined aperture for the receiving optic. A light-conducting device arranged between the measuring aperture and the specimen enlarges the effective measuring surface of the latter so that even specimens having a large surface structure can be measured without difficulty.

Abstract: For a durable, strong fixation of adjusted optical components by means of a self-hardening substance, the fixation is distributed over at least two mutually independent fixations and the parts used for the fixation are configured and dimensioned in such a manner that the resultant volumes or layer thicknesses of the self-hardening substance are optimal.

Abstract: A measuring apparatus includes a freely moving measuring head which is connected to a stationary base unit via light conductors and an electrical cable. The radiation reflected from the sample is simultaneously measured at three different angles. For this purpose, three diode-array spectrometers are provided in the stationary base unit. The spectrum of the radiation illuminating the sample can be simultaneously measured with a fourth diode-array spectrometer.

Abstract: A reflectance measuring apparatus for contactless measurement is described, in which the result of measurement is not dependent on the distance from the test object within a predetermined range. This is attained by disposing the light source in the focus of a condenser, and by providing that the measuring area is smaller than the core region inside the irradiated area on the surface of the test object.