| 摘要 |
PROBLEM TO BE SOLVED: To measure the quantity of the segment of a lens precisely by excluding an influence of floating of lens, etc., during its measurement, without being influenced by waviness, defects, etc., even when a lens having waviness or defects, etc., are measured. SOLUTION: Displacement of both front and rear surfaces of a lens 1 at a plurality of measuring parts on the same circumference of the lens 1, are measured respectively rotating the lens 1 by a roller 6 driven by a motor 7, by the use of a displacement measuring element which measures the displacement of the lens surface of a peripheral measuring part of the lens 1, and a displacement measuring element 4a which is arranged facing this displacement measuring element 4 and measures the displacement of the lens rear. From these measured displacement values the thickness of the lens at each measuring part is computed by a computing element 20, and the quantity of the segment of the lens is computed from the difference between the maximum value and the minimum value of computed lens thicknesses at all measuring parts on the same circumference of the lens 1. As the result of the measurement, the quantity of the segment and its thickness distribution are displayed on a display 29.
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