Carl-zeiss-stiftung

Siegfried Korn

Erwin J Daniels

Bernd Kratzer

Otto Muckenhaupt

The invention is directed to a multifocal spectacle lens having an especially large near-vision part. A supplementary component is fused into a base dimensioned for the near-vision range. The supplementary part is for at least one distance-vision range. In this connection, it is especially advantageous to select the refractive index of the base to be greater than the refractive index of the supplementary component. Compared to known multifocal lenses made in one piece, the multifocal lens of the invention avoids steps or substantial image jumps between the near-vision and distant-vision regions. For shortsighted wearers of spectacles, the lenses are thinner and therefore lighter.

Multifocal spectacle lens having a large near-vision part

A multifocal spectacle lens having a single base lens member and at least two additional parts adjacent to each other, attached to the base lens member by fusing or cementing. These additional parts are so shaped that imaginary tangential planes lying in the center of separation lines between the additional parts and tangential to the curved surfaces which effect changes in power extend in pairs of planes which are parallel to each other, in a manner to avoid any jump in the image when the line of sight moves from one of the additional parts to the adjacent additional part.

Multifocal spectacle lens

A method of producing photochromic multifocal spectacle lenses by fusion of a reading segment with a photochromic major lens portion. The reading segment and the main photochromic portion of the lens are fused together at a temperature which does not adversely affect the photochromic properties of the glass. In one embodiment of the invention, the parts are fused at a temperature in the tempering range but below the turbidity range of the photochromic glass, and are held at the fusing temperature for a sufficiently limited time so that turbidity does not occur. In another embodiment of the invention, the temperature of the glass is raised rather rapidly through the tempering range and through the turbidity range to a point above the turbidity range, and fusion occurs above this range, and then the glass is cooled rather rapidly down through the turbidity range and through the tempering range. It is found that if this is done sufficiently fast, the photochromic properties of the main piece of glass are not adversely affected even though the glass has passed through the temperature range which is normally considered to be the turbidity range. Various details of procedure are described.

Growing community of inventors

Oberkochen, Germany

Siegfried Korn