Abstract: A device is provided for the optical detection of form errors of a low order, for example of roughness. The device possesses a light source whose light probes the body to be examined and a light-receiving device for the light reflected by the body. The device is characterized by the fact that the light-receiving device consists of a number of light-receiving elements arranged in linear array and that an evaluation unit determines the inclination angle of the probed surface element of the body from all output signals of the light-receiving elements. Shifts in the core of the reflected light beam can be measured which are substantially below the width of a light-receiving element. The measuring results remain practically unaffected by form deviations of a higher order such as roughness etc.

Abstract: An arrangement for determining the surface structure and especially the roughness of a specimen which includes an image lens system that focuses a parallel ray onto the surface to be examined with an inclined incidence direction and a lens system which reproduces the reflected light beam on a detector array. The distance of the detector array is approximately equal to the focal distance of the lens system. The distance of the surface from the lens systems is also approximately equal to the focal distance of the lens systems. The arrangement according to the invention offers the advantage that also with an areal specimen illumination as well as with greater changes of the distance between the arrangement and the surface to be examined, an unequivocal coordination exists between the angle, under which the light is reflected, and the individual detector elements.