| 摘要 |
PURPOSE:To improve measuring accuracy of magnitude of eccentricity, by, from 3 co-ordinates on the No.1 inside periphery of an information circular disc fixed on the X-Y axis, and from 3 co-ordinates of the No.2 inside periphery, detecting the central co-ordinates of each in side periphery and detecting a magnitude of eccentricity on the basis of them. CONSTITUTION:Three areas containing the No.1 inside periphery 2 of an information circular disc 1 fixed on an X-Y table 10 available for movements on the X-Y axis and three areas containing the No.2 inside periphery 4 of an information area 3 are image-pickup scanned by an optical converting means 12 and by the X-Y co-ordinate axes through an optical system 11 consecutively. a circle-centered calculating circuit 16 calculates an image signal and the central co-ordinates of the in side periphery 2 from the three co-ordinates on the No.1 inside periphery 2 of the disc 1, through binary circuit 13, X-Y co-ordinate detecting circuit 14 and X-Y coordinate converting circuit 15 and further, the central co-ordinates of the No.2 inside periphery on the No.2 inside periphery 4 are calculated. Next, the magnitude of eccentricity calculating circuit 17, by subtracting each central co-ordinates X, Y, calculates for output of X- eccentricity signal and Y-eccentricity signal. |
