Pair of multifocal progressive spectacle lenses
US6186626A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 16, 1998 |
| Grant date | Feb 13, 2001 |
| Priority date | — |
| Expiry date | Oct 16, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02C7/061
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
The invention relates to a pair of progressive ophthalmic spectacle lenses; each lens has an aspherical surface with a far vision zone, an intermediate vision zone and a near vision zone, and good monocular and binocular foveal vision along the principal meridian. At each point of the aspherical surface there is a mean sphere which is proportional to the half sum of the maximum and minimum radii of curvature expressed in meters, and to the refractive index of the lens material. The invention suggests reducing, for a given direction of sight, the absolute value of the difference between a binocularity parameter for two points in the object space. The binocularity parameter is defined for a point in the object space as the relative difference .DELTA.S of the mean sphere for the points of the aspherical surface of the right and left lenses through which the wearer sees said point.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.