| 摘要 |
An aspherical spectacle lens that has a pair of first and second refractive surfaces, one or both of which have an aspherical shape. In this lens, the first refractive surface and/or the second refractive surface is defined by the following equation:ch is not less than 2; n an integer which is not less than 1; X a length of a perpendicular drawn from a point, which is positioned on the aspherical surface and is located at a distance rho from an optical axis, to a meridional plane, which contacts the aspherical surface at a vertex thereof; C curvature at the vertex of the aspherical surface; rho a distance from the optical axis; k what is called a cone constant; and Ami what is called an aspherical-surface coefficient of rho mi. Thus, there is provided an aspherical spectacle lens in which decentration aberration is small. Moreover, the design of the lens is performed by taking oblique astigmatic error and mean oblique error due to decentration into consideration. Thus, the performance degradation due to the decentration occurring in the aspherical lens can be reduced. |
