Patent ID: 7399080
Filing Date: 2008-07-15
Classification: G02C

Abstract:
1. a bi-aspherical type progressive-power lens with a progressive refractive power action dividedly allotted to a first refractive surface being an object side surface and a second refractive surface being an eyeball side surface, wherein when on the first refractive surface, a surface refractive power in a horizontal direction and a surface refractive power in a vertical direction, at a farsightedness diopter measurement position F on the first refractive surface, a surface refractive power in a horizontal direction and a surface refractive power in a vertical direction, at a nearsightedness diopter measurement position N surface astigmatism components at F a distribution of astigmatism on the first refractive surface is bilaterally symmetrical with respect to one meridian passing through the farsightedness diopter measurement position F