Interference measuring device and method of measurement using the same device

A method of measurement by optical interference, the method using an interference measuring device comprising:

• a light source for emitting light;
• an interferometric objective lens comprising:
• a reference mirror disposed in a reference beam path;
• and
• a beam splitter being configured to split the incident light into a beam traveling along the reference beam path and a beam traveling along a measurement beam path and being configured to combine the beam reflected off the reference mirror with the beam reflected off a measurement object disposed in the measurement beam path before emitting the combined beams;
• imaging means for taking an image of the combined beams forming thereon;
• and
• an aperture stop disposed in an optical path linking the interferometric objective lens, the light source, and the imaging means together, the aperture stop being movable along an optical axis of the interferometric objective lens,
• wherein the method comprises shifting the aperture stop from a focal point of the interferometric objective lens toward the imaging means to measure the measurement object having a convex shape, the focal point being adjacent to the imaging means, and shifting the aperture stop from the focal point of the interferometric objective lens toward the interferometric objective lens to measure the measurement object having a concave shape.