Abstract: A method for detecting surface defects, such as slip line type defects, on a substrate designed to be used in electronics, optoelectronics or analogue, including projection of a pattern of light fringes and dark bands onto the substrate, relative displacement of the substrate relative to the pattern, acquisition of a sequence of at least three images of the pattern reflected by the substrate to a sensor, the images corresponding to displacement of the fringes of the pattern, determination of the gradient of the surface of the substrate using displacements of fringes of the pattern, and determination of the presence of a surface defect on the substrate using variations in the gradient of the surface of the substrate. Another embodiment comprises a device using said method.