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. 06, 2004
Filed:
Oct. 16, 2001
Yoshimi Obara, Tokyo, JP;
PENTAX Corporation, Tokyo, JP;
Abstract
Disclosed is a single-vision astigmatic-power spectacle lens having cylindrical power to correct astigmatism of an eye. The spectacle lens has front and back surfaces, one of which is a rotationally-asymmetrical aspherical surface. The rotationally-asymmetrical aspherical surface has a first rotationally-asymmetrical component to add said cylindrical power for correcting astigmatism of an eye and a second rotationally-asymmetrical component to correct the aberrations in the directions between first and second principal meridians caused by adding the cylindrical power. That is, when the sag z(h, &thgr;) is expressed as a function of the angle &thgr; while fixing the distance h from the center, a curve of the function has a larger gradient in close to the local maximum and a smaller gradient in close to the local minimum as compared with the curve interpolated by the sine curve.