| 摘要 |
PROBLEM TO BE SOLVED: To provide a displacement measuring method which can measure the position and displacement of a measured body with high precision irrelevantly to the surface state of the measured body. SOLUTION: The light emitted by a light source 12 is condensed by an objective 15 to irradiate the surface of the measured body 16 and the light reflected by the surface of the measured body 16 is received by a photodetector 20. On the surface of the measured body 16, the light intensity curve is found while the objective 15 is moved along the optical axis. A threshold Pth is found from plural light intensity curves which are thus obtained, the gravity center position of the area encircled with the light intensity curves and the threshold, and the focus position of the objective 15 when objective 15 is at the gravity center position is decided as the surface position of the measured body 16.
|
