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:
Apr. 28, 1998
Filed:
Dec. 26, 1995
Hiroyuki Mukaiyama, Nagano-ken, JP;
Tadashi Kaga, Nagano-ken, JP;
Seiko Epson Corporation, Tokyo, JP;
Abstract
A progressive power lens provides a large clear vision area from a far-distance use section to a progressive section, wherein an astigmatism imbalance during vision through both eyes is eliminated, and eye movement between far and near distance use takes place smoothly. Astigmatism is distributed asymmetrically in the progressive region of the progressive power lens with respect to a meridian in such manner that a larger astigmatism occurs in a nose-side region than in an ear-side region. By so doing, distribution of astigmatism in the nose-side progressive region is eased to match that of the ear-side progressive region. Moreover, by making the increasing ratio .beta. of the astigmatism in the far-near direction milder than the increasing ratio .alpha. of the astigmatism in the left-right direction, a large clear vision area is obtained and the astigmatism imbalance during vision with both eyes is eliminated. Moreover, eye movement between the far-distance use and near-distance use takes place smoothly.