The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 13, 1998
Filed:
Sep. 19, 1996
Akira Kitani, Tokyo, JP;
Hoya Corporation, Tokyo, JP;
Hoya Lens Corporation, Tokyo, JP;
Abstract
A progressive power multifocal lens by which a substantially good 'broad field of view' can be obtained for an eyeglass wearer without increasing time and cost required to produce the prescribed surface thereof. This progressive power multifocal lens belongs to a group of progressive power multifocal lenses designed under a certain rule in such a manner that fundamental elements such as a far vision power measuring position F and a near vision power measuring position N thereof meet a common wearing object. Further, in the case of this lens, a surface refractive power (in units of diopters) at the far vision power measuring position F is employed as a base curve (Bi). Moreover, a difference in surface refractive power between the far vision power measuring position F and the near vision power measuring position N is employed as an addition Di (in units of diopters). Furthermore, let W(Di, Bi) denote a width of a region in which values of a surface average additional refractive power along a horizontal section line extending below the near vision power measuring position N are not less than Di/2. In such a case, when arbitrary two progressive power multifocal lenses, whose additions are Da and base curves are B1 and B2, respectively, are extracted or selected from the group of the progressive power multifocal lenses, the following relation holds for B1>B2: