Method for checking a geometric characteristic and an optical characteristic of a trimmed ophthalmic lens and associated device

Patent metadata

Field	Value
Publication number	US-10416038-B2
Application number	US-201615743537-A
Country	US
Kind code	B2
Filing date	Jul 28, 2016
Priority date	Jul 30, 2015
Publication date	Sep 17, 2019
Grant date	Sep 17, 2019

Abstract

Disclosed is a method for checking at least one geometric characteristic and one optical characteristic of a trimmed ophthalmic lens ( 10 ) including the following steps: a) arranging the trimmed ophthalmic lens on a support ( 110 ), b) capturing at least one image of the trimmed ophthalmic lens, c) determining, from the image, a measured geometric characteristic of the trimmed ophthalmic lens, d) determining at least one measured optical characteristic of the trimmed ophthalmic lens in a reference frame of the image captured in step b), e) comparing the measured geometric characteristic associated with the measured optical characteristic to a predefined desired ophthalmic lens model, including at least one desired geometric characteristic and one associated desired optical characteristic. Also disclosed is an associated checking device.

First claim

The invention claimed is:

1. A method for checking at least one geometric characteristic and one optical characteristic of an edged ophthalmic lens, the method comprising the following steps:
a) placing the edged ophthalmic lens on a holder;
b) capturing at least one image of the edged ophthalmic lens;
c) measuring, based on the captured image, a measured geometric characteristic of said edged ophthalmic lens;
d) measuring at least one measured optical characteristic of the edged ophthalmic lens in a coordinate system of the image captured in step b);
e) comparing said measured geometric characteristic associated with the measured optical characteristic to a predetermined desired ophthalmic-lens model that comprises at least one corresponding desired geometric characteristic and one corresponding desired optical characteristic; and
f) determining and recording errors in one or more of an optical center and an optical axis of the edged ophthalmic lens based on the comparison of the measured geometric characteristic and the predetermined desired ophthalmic-lens model.

2. The method as claimed in claim 1 , wherein, in step c), said measured geometric characteristic is the measured outline of the edged ophthalmic lens, and
in step e), the desired ophthalmic-lens model comprises a desired outline.

3. The method as claimed in claim 2 , wherein, in step d), said optical characteristic comprises the position of the optical center and/or the direction of an optical axis of the edged ophthalmic lens, and the following substeps are carried out:
d 1 ) prior to step c), placing the edged ophthalmic lens in a lensmeter and making a mark on said edged ophthalmic lens, said mark indicating the optical center and/or the direction of said optical axis on said edged ophthalmic lens, and
d 2 ) identifying the image of the mark in the image captured in step b).

4. The method as claimed in claim 2 , wherein the holder of said edged ophthalmic lens is located between an image-capturing apparatus configured to capture the image of the edged ophthalmic lens in step b), and a device configured to display a stationary pattern, in step d), by virtue of said image-capturing device, an image of the stationary pattern being captured through the edged ophthalmic lens, said optical characteristic being determined depending on the image of the stationary pattern.

5. The method as claimed in claim 2 , wherein the holder of said edged ophthalmic lens is located between an image-capturing apparatus configured to capture the image of the ophthalmic lens in step b), and a device configured to display a scrolling pattern, in step d), by virtue of said image-capturing device, a plurality of images of the scrolling pattern being captured through the edged ophthalmic lens, said optical characteristic being determined depending on the plurality of images.

6. The method as claimed in claim 2 , wherein, in step c), said measured geometric characteristic is the measured outline of the edged lens, and
in step e), the desired ophthalmic-lens model comprises a desired outline, and
the following substeps are carried out:
e 1 ) superposing the measured outline on the desired outline by minimizing the discrepancy therebetween, and
e 2 ) determining the discrepancy between the measured optical characteristic and the desired optical characteristic depending on the superposition obtained in step e 1 ).

7. The method as claimed in claim 1 , wherein, in step d), said optical characteristic comprises the position of the optical center and/or the direction of an optical axis of the edged ophthalmic lens, and the following substeps are carried out:
d 1 ) prior to step c), placing the edged ophthalmic lens in a lensmeter and making a mark on said edged ophthalmic lens, said mark indicating the optical center and/or the direction of said optical axis on said edged ophthalmic lens, and
d 2 ) identifying the image of the mark in the image captured in step b).

8. The method as claimed in claim 1 , wherein the holder of said edged ophthalmic lens is located between an image-capturing apparatus configured to capture the image of the edged ophthalmic lens in step b), and a device configured to display a stationary pattern, in step d), by virtue of said image-capturing device, an image of the stationary pattern being captured through the edged ophthalmic lens, said optical characteristic being determined depending on the image of the stationary pattern.

9. The method as claimed in claim 1 , wherein the holder of said edged ophthalmic lens is located between an image-capturing apparatus configured to capture the image of the ophthalmic lens in step b), and a device configured to display a scrolling pattern, in step d), by virtue of said image-capturing device, a plurality of images of the scrolling pattern being captured through the edged ophthalmic lens, said optical characteristic being determined depending on the plurality of images.

10. The method as claimed in claim 9 , wherein, in step d), the scrolling pattern displayed by the display device has a predetermined spatial period and said plurality of images comprise a number m of images, each capture of one image of said plurality of images by the image-capturing device corresponding to the display of the scrolling pattern shifted by a distance equal to 1/m times the spatial period of the scrolling pattern with respect to the preceding capture.

11. The method as claimed in claim 10 , wherein, in step d), determining an improved image of said edged ophthalmic lens by applying statistical processing to said plurality of images of the scrolling pattern through the edged ophthalmic lens.

12. The method as claimed in claim 11 , wherein, in step d), in said improved image of said edged ophthalmic lens, the image of at least one of the following elements is identified:
engravings produced on the surface of the edged ophthalmic lens or in the volume of the edged ophthalmic lens,
a measured outline of the edged ophthalmic lens,
an outline of a zone of different optical power to optical power of the rest of the edged ophthalmic lens, and
defects in the coating(s) of the edged ophthalmic lens.

13. The method as claimed in claim 1 , wherein, in step c), said measured geometric characteristic is the measured outline of the edged lens, and
in step e), the desired ophthalmic-lens model comprises a desired outline, and
the following substeps are carried out:
e 1 ) superposing the measured outline on the desired outline by minimizing the discrepancy therebetween, and
e 2 ) determining the discrepancy between the measured optical characteristic and the desired optical characteristic depending on the superposition obtained in step e 1 ).

14. The method as claimed in claim 1 , wherein, in step d), said measured optical characteristic of the edged ophthalmic lens comprises at least one of the following characteristics:
a position of the optical center,
a direction of the optical axis,
a measured direction of a tint gradient of the edged ophthalmic lens, and
a measured direction of a polarization axis of the edged ophthalmic lens.

15. The method as claimed in claim 1 , wherein, in the step f), determining a parameter relating to the discrepancy between said measured geometric characteristic and said desired geometric characteristic and a parameter relating to the discrepancy between said measured optical characteristic and said desired optical characteristic, depending on the comparison made in step e), in order to determine the errors in one or more of the optical center and the optical axis of the edged ophthalmic lens

Assignees

• Essilor Int

Inventors

• Lemaire Cedric
• Lippens Xavier

Classifications

• G01N2021/9583

  Lenses · CPC title

• G01M11/0264

  by using targets or reference patterns · CPC title

• G01M11/025

  by determining the shape of the object to be tested (measuring contours or curvatures by optical means G01B11/24) · CPC title

• G01M11/0221

  by determining the optical axis or position of lenses · CPC title

• G02C13/005

  Measuring geometric parameters required to locate ophtalmic lenses in spectacles frames (apparatus for testing or instruments for examining the eyes per se A61B3/00; machines or devices and accessories for grinding the edges of lenses using spectacles as a template B24B9/144) · CPC title