Patent · US Expired

Multifocal surface for a multifocal spectacle lens

US5137343A · kind A · utility

18Cited by

5References

5Claims

0Family size

Assignee

Carl Zeiss Stiftung · DE

Inventors

Gerhard Kelch · Aalen, DE
Hans Lahres · Aalen, DE
Helmut Wietschorke · Laberweinting, DE

Key dates

Filing date	Apr 19, 1991
Grant date	Aug 11, 1992
Priority date	—
Expiry date	Apr 19, 2011

Classification

Technology area (CPC G)Physics
CPC primaryG02C7/065
WIPO fieldOptics
WIPO sectorInstruments

Abstract

The invention is directed to a multifocal surface for a multifocal lens which, for a short progression zone between a far-vision zone and near-vision zone, has a large usable width of this zone and the near-vision zone, and for which the maximum value, which the surface astigmatism reaches on the multifocal surface, is less than the 1.1 multiple of the surface increment. Such a multifocal surface is obtained when this surface is configured as twice continuously differentiable and satisfies a combination of six features which relate to the distribution of surface astigmatism and mean surface refractive power across the multifocal surface.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.