METHOD AND APPARATUS FOR MEASUREMENT OF DECENTRATION OF ASPHERIC LENS

摘要

PURPOSE: To easily and surely measure the decentration of an aspheric surface in an aspheric lens. ;CONSTITUTION: A straight line which is passed through the first-surface paraxial curvature center O₁₀ and the second-surface paraxial curvature center O₂₀ at a lens 6, to be inspected, at least a first surface of which is an apsheric surface is designated as a straight line (m). Then, a condensed luminous to flux by an objective lens whose optical axis is made agree with the straight line (m) is shone at an aspheric surface part P₁H which is separated by a distance H from the straight line (m) on the first surface 61 in such a way that it is condensed on the curvature center according to the design of the aspheric surface part. After a reflected luminous flux by the spheric surface part P₁H has been transmitted through the objective lens, the very small decentration amount of the first surface 61 is measured on the basis of an angle θ formed with the straight line (m).;COPYRIGHT: (C)1996,JPO