SURFACE DEFECT INSPECTION

摘要

PURPOSE:To determine the correspondence between a defect detection data obtained and positions of defects on the surface of a rotating object to be inspected easily, by detecting the angle of rotation of the object being inspected at the start of inspection and at the end thereof to make an angular correction based thereon. CONSTITUTION:An object 5 to be inspected such as original magnetic disc panel is placed on a turntable 4 to be rotated with rotary motor 3 installed on a slide table 6 and the table 6 is moved horizontally in translation with a motor 7. The surface of the object 5 being inspected is irradiated with a light beam 8 and a detector 9 is arranged to detect a surface defect of the object 5 being inspected from the reflected light or the like thereof. With the rotary translation of the tables 4 and 6, a rotary detection pulse is outputted to an arithmetic control section 12 from a rotary encoder 10. The control section 12 converts counts of the detection pulse into the angle of rotation to be memorized into a memory 12b and a data from the detector 9 is compared with a specified reference value to detect a surface defect. An angular correction is performed according to a difference between the angle of rotation at the start of inspection and that at the end thereof to determine the correspondence between the detection data and the position of a defect.