Lap having a layer conformable to curvatures of optical surfaces on lenses and a method for finishing optical surfaces

Abstract

In a conformable lap and related method for finishing ophthalmic lens surfaces, a rigid base surface of the lap defines a nominal ophthalmic lens curvature corresponding to a predetermined range of curvatures. A work surface of the lap is defined by a thin, hard, polymeric material extending adjacent to the base surface for contacting a selected ophthalmic lens surface and conforming to the curvature of the selected surface. A selectively conformable substance consisting of a mixture of thermoplastic and metallic particles forms a layer extending between the rigid base surface and the work surface, and is selectively changeable between solid and non-solid forms. In its non-solid form the conformable substance permits movement of the work surface relative to the base surface to conform to the curvatures of any one of a plurality of ophthalmic lens curvatures within the predetermined range of curvatures, and in its solid form the substance fixes the work surface in a position conforming to the curvature of a selected lens surface and retains the conforming position during finishing of the lens surface.

What is claimed is:  
     
         1 . A conformable lap for finishing optical surfaces, comprising: 
 a rigid base surface defining a base curvature;    a work surface extending adjacent to the base surface for contacting a selected optical surface and conforming to the curvature of the selected optical surface; and    a selectively conformable substance forming a layer extending between the rigid base surface and the work surface and selectively changeable between solid and non-solid forms, wherein the substance in its non-solid form permits movement of the work surface relative to the base surface to conform to the curvature of the selected optical surface, and the substance in its solid form fixes the work surface in a position conforming to the curvature of the selected optical surface and retains said conforming position during finishing of the selected optical surface.    
     
     
         2 . A conformable lap as defined in  claim 1 , wherein the selectively conformable substance includes a thermoplastic which is in its solid form at or below approximately the ambient temperature of the lap and is changeable into its non-solid form in response to the application of thermal energy thereto.  
     
     
         3 . A conformable lap as defined in  claim 2 , further comprising means for controlling the temperature of the substance for selectively changing the substance between the solid and non-solid forms.  
     
     
         4 . A conformable lap as defined in  claim 3 , wherein the rigid base surface is formed of a thermally-conductive material, and the means for controlling the temperature of the substance includes means for introducing a temperature-controlled fluid into thermal communication with the base surface for controlling the temperature of the base surface and, in turn, controlling the temperature of the conformable substance in thermal communication with the base surface.  
     
     
         5 . A conformable lap as defined in  claim 4 , wherein the means for introducing a temperature-controlled fluid includes a discharge end having at least one opening for introducing relatively hot fluid to an approximately central portion of the base surface and a plurality of openings for introducing relatively cold fluid to central and side portions of the base surface.  
     
     
         6 . A conformable lap as defined in  claim 4 , wherein the means for introducing a temperature-controlled fluid includes at least one fluid channel coupled in fluid communication with the base surface, and a temperature-controlled fluid source coupled in fluid communication with the at least one conduit for introducing a temperature-controlled fluid into thermal communication with the base surface to thereby control the temperature of the base surface.  
     
     
         7 . A conformable lap as defined in  claim 6 , wherein the means for introducing a temperature-controlled fluid includes a hot fluid pipe and a cold fluid pipe.  
     
     
         8 . A conformable lap as defined in  claim 7 , wherein the hot fluid pipe and the cold fluid pipe are substantially concentric.  
     
     
         9 . A conformable lap as defined in  claim 8 , further comprising a drain pipe disposed substantially concentric with the hot and cold fluid pipes to allow fluid to drain after being in communication with the underside of the conformable lap.  
     
     
         10 . A conformable lap as defined in  claim 2 , wherein the selectively conformable substance further includes particles for enhancing the thermal-conductivity of the substance.  
     
     
         11 . A conformable lap as defined in  claim 10 , wherein the particles are metal.  
     
     
         12 . A conformable lap as defined in  claim 1 , wherein the work surface is defined at least in part by a polymeric layer superimposed over and in contact with the layer of selectively conformable substance.  
     
     
         13 . A conformable lap as defined in  claim 12 , wherein the work surface is further defined by a finishing pad mounted on an opposite side of the polymeric layer relative to the selectively conformable substance.  
     
     
         14 . A conformable lap as defined in  claim 12 , wherein the polymeric layer is less than approximately 10 mils thick.  
     
     
         15 . A conformable lap as defined in  claim 1 , wherein the base curvature defines a nominal ophthalmic lens curvature, and the layer of selectively conformable substance allows modification of the nominal curvature within a predetermined range of ophthalmic lens curvatures.  
     
     
         16 . A method for finishing a selected optical surface with a conformable lap having a rigid base surface defining a base curvature suitable for a predetermined range of optical surface curvatures, a work surface extending adjacent to the base surface for contacting a selected optical surface and conforming to the curvature of the selected optical surface, and a selectively conformable substance forming a layer extending between the rigid base surface and the work surface, and selectively changeable between solid and non-solid forms, the method comprising the steps of: 
 determining the curvature of the selected optical surface;    selecting the base curvature and thickness of the layer of conformable substance to allow the work surface to conform to the curvature of the selected optical surface;    changing the conformable substance from the solid to the non-solid form;    pressing the selected optical surface into contact with the work surface, and in turn conforming the work surface and underlying layer of selectively conformable substance to the curvature of the selected optical surface;    with the selected optical surface pressed into conforming contact with the work surface, changing the selectively conformable substance from the non-solid to the solid form to thereby cause the work surface to adopt the curvature of the selected optical surface; and    with the selected optical surface conformably contacting the work surface, moving at least one of the optical surface and work surface relative to the other to finish the optical surface.    
     
     
         17 . A method as defined in  claim 16 , wherein the step of moving at least one of the optical surface and work surface relative to the other includes moving the optical surface along a path defined by the optical surface curvature.  
     
     
         18 . A method as defined in  claim 16 , comprising the steps of: 
 fixedly securing the work surface, and moving the optical surface along a predetermined path relative to the work surface.    
     
     
         19 . A method as defined in  claim 16 , further comprising an intermediate step of: 
 placing a pad onto the work surface subsequent to work surface adopting the curvature of the selected optical surface; and    reconforming the work surface with the pad placed thereon to compensate for the thickness of the pad.    
     
     
         20 . A method as defined in  claim 19 , further comprising a subsequent step of directing water onto the pad.