Carl-zeiss-stiftung

Bernd Kratzer

Hermann Schurle

Erwin J Daniels

Siegfried Korn

Otto Muckenhaupt

The invention is directed to an ophthalmic lens having a marking and a method of producing the same. The lens is suitable for spectacles and the like. The method includes applying a removable adhering substance to a region of the surface of the lens body so that the peripheral outline of the substance corresponds to the marking to be formed. Then, an anti-reflection coating is applied to the lens body and, at a time thereafter, the adhering substance and the portion of the coating covering the substance is removed thereby causing a recess to be formed in the coating having a peripheral outline defining the marking. The marking formed in this way is practically invisible to a person wearing spectacles equipped with the lens of the invention. On the other hand, the marking is clearly visible when viewed in reflected light.

Ophthalmic lens with a marking and method of producing the marking

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.

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Huttlingen, Germany

Bernd Kratzer