Back to results
US 4,073,579 AGranted
Ophthalmic lens with locally variable index of refraction and method of making same
AssigneeAmerican Optical Corporation
InventorsEmil W. Deeg, David A. Krohn
Life of this patent
Estimating the term…
Abstract
Ophthalmic lenses with locally variable indices of refraction produced from microporous glass bodies diffused with inorganic salts and rendered transparent by heat treatment. Local variations in refractive index result from differences in concentrations of the salts produced by controlled diffusion and/or selective leaching after impregnation of the porous bodies.
Claims8
The method of making an ophthalmic lens having locally variable index of refraction comprising the steps of:
- shaping a piece of microporous glass to the configuration desired of a blank from which said lens may be formed, said blank being greater in size than desired of said lens;
- placing a side of said blank in contact with a solution of an inorganic salt to cause at least partial filling of a preselected portion of said blank with said solution by capillary forces of open pores of said glass;
- removing said blank from said salt solution and causing evaporation of the solvent of said solution from said pores and precipitation of said salt in said preselected portion of said blank;
- heating the thus dried blank to a temperature and for a period of time sufficient to close said pores and render said blank transparent with local variations of its composition in said portion containing said precipitated salt, said variations in composition causing corresponding variations in refractive index, and
- grinding and polishing said heat-treated blank to the meniscus shape, size and surface finish of an ophthalmic lens.
2 more elements
Dependencies are inferred from the claim text.