PROGRESSIVE LENSES

摘要

PURPOSE: A progressive lenses is provided to form various focuses by varying a refractive index of a lens material, as maintaining a constant curvature radius of a lens. CONSTITUTION: According to the progressive lenses(10), a curvature radius is formed constantly without regard to focus length in all regions of a far vision viewing portion(12) and a near vision viewing portion(16) and an intermediate vision viewing portion(14). A refractive index of a lens in the far vision viewing portion and the near vision viewing portion is a single refractive index capable of forming a required focus length by considering curvature phenomenon of each lens. A refractive index of the lens in the intermediate vision viewing portion is successively increasing or decreasing, and the increase or decrease of the refractive index is realized by varying ingredient content of the lens material.