Method for inspecting ophthalmic lenses for translucency defects

Abstract

This invention provides a method for inspecting ophthalmic lenses for translucency defects. [Solution] A method for inspecting an ophthalmic lens for the presence of unacceptable translucent defects in the lens body of an ophthalmic lens includes the steps of: illuminating the lens body with laser light in a region bounded by the edge of the lens body; detecting the intensity of the laser light scattered by the illuminating lens body in a predetermined detection direction different from the direction of reflection; comparing the detected intensity of the scattered laser light with a predetermined threshold intensity; determining the size of at least one coherent region in which the detected intensity of the scattered laser light is higher than the predetermined threshold intensity; determining whether the size of at least one coherent region is larger than a predetermined threshold size; and, if the size of at least one coherent region is larger than the predetermined threshold size, discarding the ophthalmic lens.

Claims

1. A method for examining an ophthalmic lens (1) (especially an intraocular lens) for the presence of an unacceptable translucent defect (12) in the lens body (10) of the ophthalmic lens, The steps include illuminating the lens body (10) of the ophthalmic lens (1) (especially the intraocular lens) with laser light (20) in a region bounded by the edge (100) of the lens body (10), The steps include detecting the intensity of the laser light (21) scattered by the lens body (10) in a predetermined detection direction different from the direction of reflection (22) of the laser light (20) that illuminates the lens body, The steps include comparing the intensity of the laser light (21) scattered by the lens body (10) with a predetermined threshold intensity, A step of determining the size of at least one coherent region (120) in which the intensity of the laser light (21) scattered by the lens body (10) is higher than the predetermined threshold intensity, A step of determining whether the size of the at least one coherent region (120) is greater than a predetermined threshold size, If the size of the at least one coherent region (120) is greater than the predetermined threshold size, the ophthalmic lens (1) is excluded due to the inclusion of a translucent defect (12) in the lens body (10). A method that includes this.

2. The step of comparing the intensity of the laser light (21) scattered by the lens body (10) with a predetermined threshold intensity is performed as follows: The intensity of the laser light (21) scattered by the lens body (10) is converted into a detection grayscale value representing the intensity of the laser light (21) scattered by the lens body (10). The predetermined threshold intensity is converted to a threshold grayscale value representing the predetermined threshold intensity. The detected grayscale value is compared with the threshold grayscale value. This is done by The step of determining whether the size of the at least one coherent region (120) is greater than a predetermined threshold size is, The size of at least one coherent region where the detected grayscale value exceeds the threshold grayscale value is determined. Execute by The method according to claim 1.

3. The method according to claim 1 or claim 2, wherein a laser diode (2) is used to illuminate the lens body (10) of the ophthalmic lens (1).

4. The method according to any one of claims 1 to 3, wherein the step of illuminating the lens body (10) includes illuminating the lens body (10) with a laser beam that strikes the surface of the lens body (10) only within the boundary of the edge (100) of the lens body (10), the laser beam having a steady-state impact profile (200, 201) that covers at least 80% of the area of ​​the surface of the lens body (10).

5. The method according to claim 4, wherein the laser beam is sighted with uniformly distributed intensity, and the steady-state collision profile (200) is a circular profile having a diameter (D2) that is 5% to 10% smaller than the diameter (D1) of the edge (100) that borders the lens body (10).

6. The method according to claim 4, wherein the steady-state collision profile (201) of the laser beam has a grid shape with grid lines (2010, 2011) arranged in a rectangle, with an intensity uniformly distributed along the grid lines (2010, 2011).

7. The method according to any one of claims 1 to 3, wherein the step of illuminating the lens body (10) includes illuminating the lens body (10) with a laser beam having impact profiles (202, 203) on the surface of the lens body (10), wherein the impact profiles (202, 203) on the surface of the lens body (10) include an area of ​​less than 20% of the area on the surface of the lens body (10), and the step of moving the impact profiles (202, 203) on the surface of the lens body (10) along a predetermined path (2020, 2030) to continuously illuminate different parts of the lens body (10).

8. The method according to claim 7, wherein the laser beam is focused, the collision profile (202) is a circular spot, and the circular spot is moved on the surface of the lens body (10) along the predetermined path (2020).

9. The method according to claim 7, wherein the collision profile (203) is a straight line, and the straight line is moved on the surface of the lens body (10) along the predetermined path (2030), and the predetermined path (2030) is perpendicular to the straight line of the collision profile (203).

Images