Patent ID: 7760365
Filing Date: 2010-07-20
Classification: G01M

Abstract:
1. A method for measuring surface decenter that is relative positional misalignment between axes of two lens surfaces of a lens under test, at least one of the two lens surfaces of the lens under test being an aspheric surface, the method comprising: a comatic aberration measurement step of measuring a transmissive wavefront of the lens under test using an interferometer equipped with a null optical element and obtaining a comatic aberration of the lens under test based on an interference fringe image obtained by the measuring; a surface-decenter comatic aberration calculation step of calculating surface-decenter comatic aberration that occurs due to the surface decenter, by subtracting surface-tilt comatic aberration that is obtained in advance and occurs due to surface tilt from the comatic aberration obtained in the comatic aberration measurement step, wherein the surface tilt is a relative inclination misalignment between the axes of the two lens surfaces; and a surface decenter calculation step of calculating the surface decenter based on the surface-decenter comatic aberration calculated in the surface-decenter comatic aberration calculation step, wherein the comatic aberration measurement step, the surface-decenter comatic aberration calculation step and the surface decenter calculation step are performed in this order.