Method for designing a lens shape and spectacle lens

Patent metadata

Field	Value
Publication number	US-10782541-B2
Application number	US-201615056792-A
Country	US
Kind code	B2
Filing date	Feb 29, 2016
Priority date	Nov 23, 2015
Publication date	Sep 22, 2020
Grant date	Sep 22, 2020

Abstract

The current invention is directed to a computer-implemented method for providing a lens shape for an ophthalmic lens. Further, there is provided a method for angular smoothing of a surface determined by carrier lines radially outwards of a prescription zone bordered by a first boundary line. Further, there is provided an ophthalmic lens, in particular a spectacle lens. Further, a method for minimizing the difference in thickness between two ophthalmic lenses for the same spectacles. A computer program product and a machine readable storage medium are provided as well.

First claim

What is claimed is:

1. A method for manufacturing an ophthalmic lens, wherein the ophthalmic lens comprises a shape determined by the following steps:
a) providing a predetermined lens shape of an ophthalmic lens having a front surface and a back surface, wherein the predetermined lens shape comprises a predetermined shape of the front surface and a predetermined shape of the back surface within a prescription zone of the back surface bordered by a first boundary line, such that the ophthalmic lens satisfies predetermined optical properties within the prescription zone;
b) determining a carrier point on the back surface within the prescription zone and a plurality of carrier lines each extending from the carrier point into a respective direction;
c) determining a transition zone of the back surface, wherein the transition zone extends radially outwards from the first boundary line towards the outer edge of the ophthalmic lens and ends at a second boundary line bordering the transition zone radially outwards;
d) for each carrier line, setting a desired constant curvature gradient over the transition zone;
e) for each carrier line, determining a curvature profile of the back surface between the first boundary line and an outer edge the ophthalmic lens along the carrier line, and wherein the curvature profile in the transition zone is determined based on the respective desired constant curvature gradient;
f) angular smoothing the back surface radially outwards of the first boundary line; and
g) manufacturing the ophthalmic lens comprising the shape defined by steps a) through f).

2. The method of claim 1 , wherein a curvature along the carrier line between the second boundary line and the outer edge is essentially constant and equals the curvature along the carrier line in the transition zone at the second boundary line.

3. The method of claim 1 , wherein the desired constant curvature gradient is set based on the curvature of the prescription zone at the first boundary line and a boundary condition for the curvature within the transition zone.

4. The method of claim 3 , wherein the curvature gradient is further set based on a desired thickness reduction of the ophthalmic lens along the carrier line.

5. The method of claim 1 , wherein the desired constant curvature gradient is set based on the curvature of the prescription zone at the first boundary line and a curvature target to be reached at the second boundary line, and wherein the curvature target is at least one of zero and a curvature of the front surface.

6. The method of claim 5 , wherein the curvature of the front surface is determined in the same coordinate system as the curvature of the back surface.

7. The method of claim 5 , wherein the front surface is a spherical surface.

8. The method of claim 1 , wherein the curvature gradient is set to be negative in case the ophthalmic lens is a minus lens and the curvature gradient is set to be positive in case the ophthalmic lens is a plus lens.

9. The method of claim 1 , wherein the curvature profile is determined by determining a cubic spline from the first boundary line to the second boundary line, wherein the cubic spline is comprised of a plurality of sections each described by a cubic polynomial, and wherein the cubical polynomials are determined section-wise from the first boundary line to the second boundary line.

10. A method for manufacturing an ophthalmic lens, wherein the ophthalmic lens comprises a shape determined by:
a) providing a predetermined lens shape of an ophthalmic lens having a front surface and a back surface, wherein the predetermined lens shape comprises a predetermined shape of the front surface and a predetermined shape of the back surface within a prescription zone of the back surface bordered by a first boundary line, such that the ophthalmic lens satisfies predetermined optical properties within the prescription zone;
b) determining a carrier point on the back surface within the prescription zone and a plurality of carrier lines each extending from the carrier point into a respective direction;
c) determining a transition zone of the back surface, wherein the transition zone extends radially outwards from the first boundary line towards the outer edge of the ophthalmic lens and ends at a second boundary line bordering the transition zone radially outwards;
d) for each carrier line, setting a desired constant curvature gradient over the transition zone:
e) for each carrier line, determining a curvature profile of the back surface between the first boundary line and an outer edge the ophthalmic lens along the carrier line, and wherein the curvature profile in the transition zone is determined based on the respective desired constant curvature gradient
f) angular smoothing the back surface radially outwards of the first boundary line; and
g) manufacturing the ophthalmic lens comprising the shape defined by steps a) through f),
wherein the curvature profile is determined by determining a cubic spline from the first boundary line to the second boundary line, wherein the cubic spline is comprised of a plurality of sections each described by a cubic polynomial, and wherein the cubical polynomials are determined section-wise from the first boundary line to the second boundary line, and
wherein the cubical polynomials are determined section-wise from the first boundary line to the second boundary line such that a sagittal height, a slope and a curvature of the back surface along the carrier line are continuous and the curvature along the carrier line changes over each section resulting in an approximated constant curvature gradient over the transition zone.

11. A method for manufacturing an ophthalmic lens, wherein the ophthalmic lens comprises a shape determined by:
a) providing a predetermined lens shape of an ophthalmic lens having a front surface and a back surface, wherein the predetermined lens shape comprises a predetermined shape of the front surface and a predetermined shape of the back surface within a prescription zone of the back surface bordered by a first boundary line, such that the ophthalmic lens satisfies predetermined optical properties within the prescription zone;
b) determining a carrier point on the back surface within the prescription zone and a plurality of carrier lines each extending from the carrier point into a respective direction;
c) determining a transition zone of the back surface, wherein the transition zone extends radially outwards from the first boundary line towards the outer edge of the ophthalmic lens and ends at a second boundary line bordering the transition zone radially outwards;
d) for each carrier line, setting a desired constant curvature gradient over the transition zone;
e) for each carrier line, determining a curvature profile of the back surface between the first boundary line and an outer edge the ophthalmic lens along the carrier line, and wherein the curvature profile in the transition zone is determined based on the respective desired constant curvature gradient;
f) angular smoothing the back surface radially outwards of the first boundary line; and
g) manufacturing the ophthalmic lens comprising the shape defined by steps a) through f,
wherein the curvature profile is determined by determining a cubic spline from the first boundary line to the second boundary line,
wherein the cubic spline is comprised of a plurality of sections each described by a cubical polynomial, and
wherein the cubical polynomials are determined section-wise from the first boundary line to the second boundary line such that a sagittal height, a slope and a curvature of the back surface along the carrier line are continuous and

Assignees

• Zeiss Carl Vision Int Gmbh

Inventors

• Spratt Ray Steven
• Ellinger Philipp
• Wietschorke Helmut
• Nolan Angela
• Varnas Saulius

Classifications

• G02C2202/04

  Lenses comprising decentered structures · CPC title

• G02C7/027

  considering wearer's parameters · CPC title

• G02C7/028 Primary

  Special mathematical design techniques · CPC title

• G02C7/063

  Shape of the progressive surface · CPC title

• G02C7/024 Primary

  Methods of designing ophthalmic lenses · CPC title