| 摘要 |
PROBLEM TO BE SOLVED: To enable improvement in a rate of fitting in a spectacle frame of a spectacle lens after V-block processing even if thinning, distortion, etc. can be caused to a V-block shape by interference of a processing tool, and realize supply of the V-block-processed spectacle lens with stable quality.SOLUTION: A perimeter calculation device comprises: predicted shape identification means 201b for obtaining a predicted finished V-block shape considering an interference amount of processing tool when applying V-block processing to an unprocessed spectacle lens; and theoretical peripheral length calculation means 201d for obtaining a V-block perimeter in a spectacle lens having the predicted finished shape obtained by the predicted shape identification means 201b, as a theoretical perimeter of the spectacle lens. |
