US3861089A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of making contact lens
Assignee: Individual
•
Filing: 1973-09-24
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Granted: 1975-01-21
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Expires: 1993-09-24
Abstract
Abstract An uncut contact lens of resilient, self-restoring plastic material having a central or base spherical curve is ground to provide a surrounding annular spherical peripheral curve of greater radius of curvature than the base curve. The lens is finish ground for a particular cornea by first warping a preselected diametral axis so that the projection of the periphery of the curve on a plane normal to the visual axis of the lens is elliptical. While the lens is maintained in this warped condition, a spherical grinding tool of selected diameter is applied coaxially with the visual axis so as to grind the peripheral curve, whereby material is removed to a greater depth and width from the peripheral curve at the ends of the minor axis of the ellipse, and progressively less is removed from the peripheral curve in a direction away from the minor axis and toward the major axis. Upon completion of the grinding, the lens is released and self-restores to its unwarped condition, in which condition the peripheral curve becomes toric.
Inventors
- 👤 Robert C England
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 11:23
CPC Classifications
B; B24; B24B; B24B13/00; B24B13/0025; Y; Y10; Y10S; Y10S451/00; Y10S451/921
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
344 words
The method of grinding a contact lens of resilient selfrestoring material and having front and rear faces, respectively, and having on its rear face a base curve of prescribed configuration surrounded by a peripheral annular curve which is generally spherical and which has a radius of curvature longer than the radius of curvature of the base curve, and of which the outermost peripheral edge of the peripheral annular curve is substantially circular, comprising: warping one or more areas of the peripheral curve portion of the lens into a condition in which the shape of the projection of the outermost peripheral edge of the peripheral curve on a plane perpendicular to the axis of the lens is out-of-round, by the application to one or more areas of the front face of the lens, which areas are aligned axially of the lens with the peripheral curve, of extraneous forces directed generally perpendicular to said front face at their points of application, while leaving the entire peripheral edge of the lens unconstrained radially of the lens axis; securing the lens fixedly iN said warped condition; then, while the lens is held firmly in said warped condition, applying a rotary spherical faced grinding tool to said rear face of the lens only on said peripheral curve with the rotary axis of the tool in substantially coaxial relation to the visual axis of the lens and, while leaving the base curve intact, grinding only the peripheral curve to a predetermined degree such that the warped portion of the peripheral curve is spherical in the warped condition and the lens material is removed from the peripheral curve to the greatest width and depth at the shortest radius of said projection and such that the width and depth of removal of material at the different circumferential portions of the peripheral curve is inversely proportional to the length of their radii, respectively; and then releasing the lens and permitting it to selfrestore to its original unwarped condition; whereby the base curve retains its prescribed contour and the peripheral curve is torically contoured.
Claim 2
Independent Claim
344 words
The method of grinding a contact lens of resilient selfrestoring material and having front and rear faces, respectively, and having on its rear face a base curve of prescribed configuration surrounded by a peripheral annular curve which is generally spherical and which has a radius of curvature longer than the radius of curvature of the base curve, and of which the outermost peripheral edge of the peripheral annular curve is substantially circular, comprising: warping one or more areas of the peripheral curve portion of the lens into a condition in which the shape of the projection of the outermost peripheral edge of the peripheral curve on a plane perpendicular to the axis of the lens is out-of-round, by the application to one or more areas of the front face of the lens, which areas are aligned axially of the lens with the peripheral curve, of extraneous forces directed generally perpendicular to said front face at their points of application, while leaving the entire peripheral edge of the lens unconstrained radially of the lens axis; securing the lens fixedly iN said warped condition; then, while the lens is held firmly in said warped condition, applying a rotary spherical faced grinding tool to said rear face of the lens only on said peripheral curve with the rotary axis of the tool in substantially coaxial relation to the visual axis of the lens and, while leaving the base curve intact, grinding only the peripheral curve to a predetermined degree such that the warped portion of the peripheral curve is spherical in the warped condition and the lens material is removed from the peripheral curve to the greatest width and depth at the shortest radius of said projection and such that the width and depth of removal of material at the different circumferential portions of the peripheral curve is inversely proportional to the length of their radii, respectively; and then releasing the lens and permitting it to selfrestore to its original unwarped condition; whereby the base curve retains its prescribed contour and the peripheral curve is torically contoured.
Claim 3
Dependent Claim
113 words
The method according to claim 1 wherein the lens is warped by mounting it in a concavity in a holder, which concavity is circular in sections normal to its axis, with the front face of the lens facing the bottom of the concavity and adhesively secured to the cavity wall, so that the major portion of the front face of the lens, aligned with the peripheral curve, is held adhesively in substantial conformance with the contour of the wall of the concavity, and said one or more areas, by said application of extraneous forces, are held warped away from said wall of the concavity and inwardly away from the rim of said concavity.
Claim 4
Dependent Claim
31 words
The method according to claim 1 wherein said forces, are applied at a plurality of areas which are spaced apart from each other circumferentially of the visual axis of the lens.
Claim 5
Dependent Claim
19 words
The method according to claim 3 wherein said forces are applied at at least three areas about the periphery.
Claim 6
Dependent Claim
35 words
the method according to claim 2 wherein the extraneous forces are applied by inserting a shim or shims between the peripheral portion of the lens and the wall of the holder concavity at said areas.
Claim 7
Dependent Claim
23 words
The method according to claim 3 wherein said forces are applied at least at two areas which are diametrically opposite from each other.
Claim 8
Dependent Claim
24 words
The method according to claim 3 wherein said forces are applied at least two areas which are out of diametral alignment with each other.
Claim 9
Dependent Claim
27 words
The method according to claim 6 wherein the forces are applied at at least one additional area which is asymmetrically arranged relative to said diametrically opposite areas.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-01-20 | 1978-07-22 | 1979-01-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-01-20 | 1982-07-22 | 1983-01-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-01-20 | 1986-07-22 | 1987-01-21 | $7700.00 | Window Closed / Lapsed |