| 摘要 |
Either one, or both, of first and second planes of an aspherical eyeglass lens having a pair of first and second refraction planes is shaped in such a manner so as to satisfy equation (I), where mi: real of number of 2 or more, n: integer of 1 or more, X: distance of perpendicular drawn from one point on aspherical plane having a distance rho from optical axis to nodal plane of aspherical plane apex; C: radius of curvature of reference sphere at aspherical apex, rho : distance from optical axis, k: cone constant, Ami: aspherical coefficient of term rho <mi>. The lens shape is determined so as to reduce the drop of performance of lens due to eccentricity in consideration of astigmatism and power error when eccentricity occurs, at the design stage of the aspherical eyeglass lens.
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