APPARATUS FOR MEASURING A GRADIENT OF A SURFACE

摘要

An apparatus for continuously measuring a gradient of a curved surface at a number of different points thereon is disclosed in which a laser beam reflected at the point to be measured on the surface makes a beam spot on a photo sensor. The photo sensor follows the beam spot while the center of the beam spot and the center of the photo sensor coincide. The displacement between the beam spot from the point subjected to measurement and the beam spot from a reference point on the surface or the photo sensor is proportional to the gradient at the point subjected to measurement. The photo sensor is, for example, a differential type which comprises four photo diodes. The numerical control table is used to determine the positional relationship of the point to be measured with respect to the laser beam, and an X-y recorder is used to follow the beam spot.