Patent ID: 6935744
Filing Date: 2005-08-30
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 said first refractive surface, a surface refractive power in a horizontal direction and a surface refractive power in a vertical direction, at a far vision diopter measurement position F on said first refractive surface, a surface refractive power in a horizontal direction and a surface refractive power in a vertical direction, at a near vision diopter measurement position N are satisfied, and surface astigmatism components at F 1 and N 1 of said first refractive surface are cancelled by said second refractive surface so that said first and second refractive surfaces together provide a far vision diopter (Df) and an addition diopter (ADD) based on prescription values.