Optics: eye examining – vision testing and correcting – Spectacles and eyeglasses – Ophthalmic lenses or blanks
Patent
1991-02-07
1992-08-11
Sugarman, Scott J.
Optics: eye examining, vision testing and correcting
Spectacles and eyeglasses
Ophthalmic lenses or blanks
51284R, 264 27, G02C 702, B29D 1100
Patent
active
051373440
ABSTRACT:
A semi-finished lens of plastic material which will be ground on the basis of a spectacles prescription to be completed as a myopia correcting single-focus lens is molded such that the convex surface is a spherical nonprocessed surface and the concave surface is a nonspherical molded surface which requires no grinding. Thus, a completed lens can be easily obtained by simply grinding the spherical convex surface. Further, the concave surface which is a nonspherical molded surface is formed as an ellipsoidal surface of revolution, hyperboloidal surface of revolution or other nonspherical surface which has a curvature providing spherical power or a combination of spherical power and astimgatic power and whose curvature decreases from the optical center toward the periphery, whereby the difficulty of grinding can be decreased and the completed lens is free from the warping of images due to spherical aberration and has an edge which is thin and makes a better appearance.
REFERENCES:
patent: 3960442 (1976-06-01), Davis et al.
patent: 4289387 (1981-09-01), Jalie
patent: 4561736 (1985-12-01), Furter
Kabushiki Kaisha Asahi Optical
Sugarman Scott J.
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