Coaxial measurement of axisymmetric aspheric lens

A method to measure coaxiality of axisymmetric aspheric lens is introduced. A laser beam is incident on the aspheric side of a tested lens through a beam waist conversion lens and the beam reflected by the aspheric surface is received by CCD camera. The position of the aspheric lens is adjusted until the center of the beam waist doesn′t move with the rotation of the tested aspheric lens. It shows that the symmetry axis of the aspheric surface is aligned with the rotation axis. Then the eccentricity of the sphere side of the tested lens is measured according to the principle of the spherical eccentric measurement. The accuracy of the measurement is better than 20″. This method is applicable to the acceptance inspection of aspheric lens and aspheric mirrors, as well as the improvement of aspheric lens process.