Progressive multifocal lens with a steep refractive power change

摘要

This invention, has had the main meridian of the promotion which passes by the distant apparent territory, the intermediate apparent territory, the Chikakata apparent territory and the aforementioned three territories, and the joining frequency which is equal to the difference of average spherical value with the Chikakata apparent territory datum point and the distant apparent territory datum point, it is something regarding the promotive multi focus spectacle lenses. As for the lens, it is defined, as vertical distance with the point and mounting center with respect to meridian of the place where just 85% of joining frequency values is larger than the average spherical value average spherical value in the distant apparent territory datum point it has possessed the promotive length under 12mm. In order to guarantee satisfactory visual property, not only around meridian in other than the central vision territory, multiplying the norm of slope of spherical value in cylinder value, the area of integral calculus and the aforementioned circle with the 40mm diameter circle which centers, the center of the lens of the product which can and maximum of norm of slope of the spherical value regarding joining frequency and the part in the meridian which is included in the aforementioned circle and, multiplying, the product which can and, ratio between is under 0.14.