| 摘要 |
PROBLEM TO BE SOLVED: To dispense with a detection of a rotation angle of a disk of an optical path length variable device in which the disk disposed with a reflector rotates, and dispense with high accuracy of a control for uniformizing a rotation speed in an apparatus for measuring a surface profile of an object or thickness of a light-transmissive object by optical coherence tomography.SOLUTION: Before being applied to an inspection object OB, laser light is made to pass through a reference light-transmissive body 23 so as to reflect on a laser light incident surface and a laser light exiting surface of the reference light-transmissive body 23, and a surface of the inspection object OB, so that, when an optical path length is changed by an optical length variable device 40, three peaks are generated on a signal output by a light receiving sensor 15. Consequently, a distance from the reference light-transmissive body 23 to the inspection object OB is calculated from time differences of generations of three peaks, the thickness of the reference light-transmissive body 23, and a reflective index. |
