System and method for inspecting optical power and thickness of ophthalmic lenses immersed in a solution

Abstract

A system for producing a high contrast image of an ophthalmic lens under inspection, comprising: top camera to view ophthalmic lens through lens module; motorized mechanism for positioning top camera at two pre-programmed positions; three illumination modules; said illumination modules focusing light through ophthalmic lens under inspection, thereby producing a high contrast image of features of ophthalmic lens; wherein ophthalmic lens is contained within cuvette with optical power of positive of ten; said cuvette mounted with two optical windows, one of them being vertical and other at an angle; said cuvette having transparent bottom glass suitably designed to position ophthalmic lens under inspection; said cuvette designed to be filled with saline solution; accurately calibrated test object positioned to achieve image of ophthalmic lens overlaid with image of pattern present on test object; additional illumination source comprising laser diode; and second camera to view ophthalmic lens through slanted optical lens module.

1 . A system for producing a high contrast image of an ophthalmic lens under inspection, comprising:
 a) a Top camera to view the ophthalmic lens through a lens module;   b) Motorized mechanism for positioning the Top camera at two pre-programmed positions;   c) three illumination modules;   d) said illumination modules focusing light through the ophthalmic lens under inspection, thereby producing a high contrast image of the features of the ophthalmic lens;   e) wherein the ophthalmic lens is contained within a cuvette with an optical power of positive of Ten;   f) said cuvette mounted with two optical windows, one of them being vertical and the other at an angle;   g) said cuvette having a transparent bottom glass suitably designed to position the ophthalmic lens under inspection;   h) said cuvette designed to be filled with Saline solution;   i) an accurately calibrated test object positioned to achieve an image of the ophthalmic lens overlaid with the image of the pattern present on the test object;   j) an additional illumination source comprising a laser diode; and   h) a second camera to view the ophthalmic lens through a slanted optical lens module.   
     
     
         2 . A system according to  claim 1 , further comprising a focusing lens. 
     
     
         3 . A system according to  claim 1 , further comprising a set of beam splitters. 
     
     
         4 . A method for inspecting defects of an ophthalmic lens, the method comprising the steps of:
 moving the Top camera to a second position;   providing an inspection cuvette designed with an optical power of positive ten, comprising an optically transparent bottom glass having a concave inner surface containing the ophthalmic lens immersed in a liquid, and positioning the inspection cuvette in the optical axis of the Top camera;   providing a separate set of illumination sources and a Top camera for receiving illumination having passed through ophthalmic lens contained in the inspection cuvette to produce multiple enhanced images of the defects in the Ophthalmic lens;   inspecting for defects such as scratches, tears and air bubbles within the Ophthalmic lens; and   removing the lens if the size of the defects detected in the Ophthalmic lens is beyond a predetermined size.   
     
     
         5 . A method for determination of lens thickness of an ophthalmic lens the method comprising the steps of:
 providing an inspection cuvette designed with an optical power of positive ten, comprising an optically transparent bottom glass designed to have an optical power of positive ten, having a concave inner surface containing the ophthalmic lens immersed in a liquid, and positioning the inspection cuvette in the optical axis of the Top camera;   providing a single laser illumination source and a second camera for receiving illumination directed by a set of beam deflectors and having passed through focusing lens and ophthalmic lens contained in the inspection cuvette, to produce a laser beam scattered image formed by the reflected rays, and measuring the distance between the two extremes of reflected rays of light.   
     
     
         6 . The method according to  claim 5 , further comprising the steps of:
 providing an inspection cuvette designed with an optical power of positive ten, comprising an optically transparent glass bottom having a concave inner surface containing the ophthalmic lens immersed in a liquid, and positioning the inspection cuvette in the optical axis of the imaging module;   providing a single laser illumination source and a second camera for receiving illumination directed by a set of beam deflectors and having passed through focusing lens and ophthalmic lens contained in the inspection cuvette, to produce a laser beam scattered image formed by the reflected rays, and measuring the distance between the two extremes of reflected rays of light; and   creating a chart (Length in pixels vs thickness) of measurements between the two extremes of the scattered laser beams of several pre-selected lenses of known thickness, to be used as a reference for determining the lens thickness of subsequent ophthalmic lenses to be inspected.   
     
     
         7 . The method according to  claim 6 , further comprising the steps of:
 providing an inspection cuvette designed with an optical power of positive ten, comprising an optically transparent bottom glass having a concave inner surface containing the ophthalmic lens immersed in a liquid, and positioning the inspection cuvette in the optical axis of the second camera;   providing a single laser illumination source and a second camera for receiving illumination directed by a set of beam splitters and having passed through focusing lens and ophthalmic lens contained in the liquid filled inspection cuvette, to produce a laser beam scattered image formed by the reflected rays, and measuring the distance between the two extremes of reflected rays of light; and   removing and segregating the ophthalmic lens from the Cuvette after determining the optical thickness of the lens under inspection, based on the chart plotted for Length in pixels vs thickness.