PURPOSE: To automatically measure and display the curvature of a processing surface plate during the processing and adjust and maintain it at a set value.
CONSTITUTION: A ring holder 6 is driven by an actuator 35, and the position of a conditioning ring 5 is adjusted. A mirror 23 is provided at the center of the end face of a rotary shaft 3a, a mirror 24 is provided at the center of the ring 5 respectively, a light beam is radiated from a laser tube 25, and reflected beams are fed to a semiconductor position detecting element 28. A controller 31 obtains the distance (d) between incidence points of two reflected beams from the signals Ix, Iy corresponding to the XY coordinates of the incidence points outputted from the element 28, calculates the radius of curvature R of the polished surface 4a from (d), and displays the locus of the incidence point of each reflected beam and the radius of curvature R on an indicator. The actuator 35 is controlled so that the radius of curvature R becomes equal to the set value.
ITO TADASHI
ICHIKAWA KAZUO
