US4498919A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for making colored photochromic prescription ophthalmic lenses
Assignee: Corning Glass Works
•
Filing: 1983-10-31
•
Granted: 1985-02-12
•
Expires: 2003-10-31
Abstract
Abstract Colored photochromic ophthalmic lenses are produced by combining a photochromic cap element having an integrally colored back surface with an ophthalmic crown base element having a prescription-ground back surface, the cap back and base element front surfaces having been finished to a matching standard base curvature, thus providing a cemented assembly exhibiting a selected combination of prescribed vision-correcting and light filtering properties.
Inventors
- 👤 George H. Mann
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 18:33
CPC Classifications
C; C03; C03C; C03C23/00; C03C23/007; B; B29; B29D; B29D11/00; B29D11/00634; B29D11/00653; B29D11/0073; C03C21/00; C03C21/001; C03C21/002
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
254 words
A process for providing a colored photochromic prescription ophthalmic lens which comprises the steps of: (a) providing a photochromic glass cap blank for a thin lens cap element to be provided with a convex front surface and a concave back surface; (b) finishing the back surface of the cap blank to a standard base curvature in the range of about 2 to 10 diopters to provide a semifinished cap blank with a concave back surface; (c) subjecting the semifinished cap blank to a heat treatment in a reducing atmosphere to cause the reduction of selected metallic constituents therein and the formation of an integral colored layer on the surfaces of the blank; (d) finishing the front surface of the cap blank to generate a front surface curvature matching the standard base curvature of the back surface, to remove front surface color, and to provide a finished cap element having a thickness not exceeding about 1.5 mm and having a convex front surface and a concave back surface; (e) providing a glass base element for the lens, said base element having a convex front surface with a standard base curvature matching that of the back surface of the finished cap element, and having a prescription-finished back surface imparting selected elements of power, cylinder, multifocal and prism correction to the base element; and (f) cementing the back surface of the colored cap element to the front surface of the base element such that the standard base curvatures mate, to provide a finished tinted prescription ophthalmic lens.
Claim 2
Dependent Claim
254 words
A process for providing a colored photochromic prescription ophthalmic lens which comprises the steps of: (a) providing a photochromic glass cap blank for a thin lens cap element to be provided with a convex front surface and a concave back surface; (b) finishing the back surface of the cap blank to a standard base curvature in the range of about 2 to 10 diopters to provide a semifinished cap blank with a concave back surface; (c) subjecting the semifinished cap blank to a heat treatment in a reducing atmosphere to cause the reduction of selected metallic constituents therein and the formation of an integral colored layer on the surfaces of the blank; (d) finishing the front surface of the cap blank to generate a front surface curvature matching the standard base curvature of the back surface, to remove front surface color, and to provide a finished cap element having a thickness not exceeding about 1.5 mm and having a convex front surface and a concave back surface; (e) providing a glass base element for the lens, said base element having a convex front surface with a standard base curvature matching that of the back surface of the finished cap element, and having a prescription-finished back surface imparting selected elements of power, cylinder, multifocal and prism correction to the base element; and (f) cementing the back surface of the colored cap element to the front surface of the base element such that the standard base curvatures mate, to provide a finished tinted prescription ophthalmic lens.
Claim 3
Dependent Claim
45 words
A process in accordance with claim 1 wherein, prior to cementing the cap element to the base element to provide the finished lens, each of the cap element and base element are thermally or chemically strengthened to a modulus of rupture strength of 25,000-40,000 psi.
Claim 4
Dependent Claim
26 words
A process in accordance with claim 2 wherein the cap and base elements are strengthened by immersion in a molten KNO 3 -NaNO 3 salt bath.
Claim 5
Dependent Claim
43 words
A process in accordance with claim 2 wherein, prior to thermally or chemically strengthening the cap and base elements, the elements are temporarily joined into a bonded assembly, subjected to an edging step in preparation for framing, and then delaminated prior to strengthening.
References Cited (Backward Citations)
US2675740A
Cited
US990303A
Cited
US2382660A
Cited
US3656923A
Cited
US3653750A
Cited
US4170567A
Cited
US4422893A
Cited
US4268134A
Cited
US4261656A
Cited
US4284686A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-02-12 | 1988-08-13 | 1989-02-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-02-12 | 1992-08-13 | 1993-02-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-02-12 | 1996-08-13 | 1997-02-12 | $7700.00 | Window Closed / Lapsed |