Patent ID: 8411288

Claim:
A method for determining the coordinates K of at least one point P 1 on an edge of an optical lens, wherein the lens is retained by a retaining device having an axis of rotation R, with the edge extending in a circumferential direction to an axis of the optical lens and to the axis of rotation, the edge to be measured is held in an optical path of an optical micrometer which measures in the direction of a Z axis, the optical micrometer transmitting a linearly extending optical path of parallel light, with the optical path running in the direction of a Y axis, wherein the relative position between the retaining device and the micrometer is known, comprising the steps of: a) holding the lens with the edge to be measured in the optical path b) determining a first Z coordinate Za for the point P 1 of the edge which is located in the optical path in a position A, wherein the point P 1 represents a maximum or minimum value of the optical path, an X coordinate Xa of the point P 1 corresponds to the X coordinate of the optical path c1) changing the relative position between the lens and the optical path by means of a pivoting movement around a pivotal axis S being inclined to the axis of rotation R, the point P 1 being located in the optical path in a position B and representing a maximum or minimum value, or c2) the lens is hit by a second optical path which has a different relative position to the lens than the first optical path, wherein the first optical path is pivoted relative to the second optical path and that the point P 1 represents a maximum or minimum value in the second optical path, and d) determining a second Z coordinate Zb for the point P 1 of the edge which is located in the optical path, and e) determining on the basis of two equation systems for the point P 1 , for both relative positions, the missing coordinates Ya and Yb and thus the position of the point P 1 .