| 摘要 |
PURPOSE:To obtain the measured data by an orthogonal coordinates even for a surface having a large inclination, by determining the rotational center of measurement of polar coordinates and subjecting the entire measured values of the polar coordinates to a correct coordinate conversion when a surface whose inclination exceeds a prescribed value is measured. CONSTITUTION:An optical system 2 for X-Y-Z measurement is moved on X- and Y-stages 3 and 4 in the directions X and Y by motors 1. Moreover, an objective lens 6 of a measuring probe is fitted to a Z-stage 5 fitted to the optical system 2. The objective lens 6 is moved in the direction Z by a focus servo so that a distance from a surface 7 to be measured to the objective lens 6 be fixed substantially. Although the optical system for X-Y-Z measurement can realize a measurement of ultra-high precision, the coverage thereof regarding the inclination of the surface to be measured is limited to + or -25 deg. when the measurement of orthogonal coordinates alone is used. When the surface having the inclination larger than + or -25 deg. is measured, accordingly, the surface 7 to be measured is rotated on an air spindle 9 around an axis passing through the center or the vicinity of a spherical surface approximate to the surface 7 and being parallel to the axis Y. The rotational angle of polar coordinates is detected by a rotary encoder 10, while the radius is measured by the optical system of Z measurement. |
