SPECTACLE LENS DESIGN METHOD AND SPECTACLE LENS

PROBLEM TO BE SOLVED: To provide a spectacle lens design method that can set an area in which improvement in specific items such as an average diopter error and the like is achieved in an arbitrary direction and size within a lens.SOLUTION: A spectacle lens design method comprises: (a) a preferential item allocation step of allocating a preferential item about a characteristic of a lens to a plurality of areas g partitioned by two sides radially expanding from a center of the lens; (b) a first aspherical shape determination step of determining a shape of a refractive surface on a plurality of division lines m extending radially from the center of the lens by an aspherical expression; and (c) a second aspherical shape determination step of determining the shape of the refractive surface located between the division lines m by an interpolation. The first aspherical shape determination step is configured to call the diopter set on the division line m and the aspherical coefficient value associated with the preferential item from a database DB1 and the like where set data composed of an aspherical coefficient value and diopter associated with the preferential item is stored; substitute the called diopter and aspherical coefficient value into the aspherical expression; and thereby determine the shape of the refractive surface on the division line m.SELECTED DRAWING: Figure 6 【課題】平均度数誤差などの特定の項目について改善が図られた領域を、レンズ内の任意の方向・大きさで設定することが可能な眼鏡用レンズの設計方法を提供する。【解決手段】（ａ）レンズの中心から放射状に延びる２辺で区画された複数の領域ｇにレンズの特性に関する優先項目を割付ける優先項目割付工程と、（ｂ）レンズの中心から放射状に延びる複数の分割線ｍ上の屈折面の形状を非球面の式にて決定する第１の非球面形状決定工程と、（ｃ）分割線ｍの間に位置する屈折面の形状を補間により決定する第２の非球面形状決定工程と、を有する眼鏡用レンズの設計方法。第１の非球面形状決定工程では、優先項目と対応付けた非球面係数値及び度数から成る組データを収納したデータベースDB1等から、分割線ｍ上に設定された度数及び優先項目に対応した非球面係数値を呼出し、非球面の式に代入することで、分割線ｍ上の屈折面の形状を決定する。【選択図】 図６