| 摘要 |
PROBLEM TO BE SOLVED: To provide an Abbe's number measuring device capable of measuring while drop in measuring accuracy caused by the number of refractivity is avoided to the utmost. SOLUTION: This Abbe's number measuring device has a lens support member 21 for supporting an inspecting lens TL installed in a measuring light path SO of the inspecting lens TL so that measuring light beams having different wave length generated in a measuring light source part 10 to measure Abbe's number of the inspecting lens TL are incident almost vertically on an incident surface TLa of the inspecting lens TL; and a detecting sensor 13 for detecting measuring light beams passing through the inspecting lens TL installed in the position opposite to the measuring light source part 10 on the boundary of the lens support member 21; and a computing circuit for computing the Abb's number based on a detected output of the detecting sensor 13.
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