Fabrication of an optical wedge

Abstract

Various embodiments are disclosed relating to fabrication of an optical wedge. For example, one embodiment provides a method for manufacturing an optical wedge comprising inserting a wedge blank into a vacuum molding tool and applying a vacuum to the vacuum molding tool to temporarily hold the wedge blank against a molding surface of the vacuum molding tool. The method further comprises removing a layer from a top surface of the wedge blank to expose a machined surface of the wedge blank, and casting a finish layer on the machined surface to form a finish layer of a finished optical wedge.

1 . A vacuum molding system for forming an optical wedge from a wedge blank, the vacuum molding system comprising:
 a vacuum pump;   a vacuum molding tool comprising one or more vacuum ports fluidly connected to the vacuum pump, the vacuum molding tool including a molding surface configured to temporarily shape a molded surface of the wedge blank under the urging of a pressure differential generated by the vacuum pump; and   a casting plate configured to be retained across a finish layer of the wedge blank opposite from the molded surface of the wedge blank.   
     
     
         2 . The vacuum molding system of  claim 1 , wherein the molding surface comprises an optical surface profile to be imparted to the molded surface of the wedge blank. 
     
     
         3 . The vacuum molding system of  claim 2 , wherein the molding surface of the vacuum molding tool includes one or more local topographic characteristics each configured to impart a complementary local topographic feature to the molded surface of the wedge blank. 
     
     
         4 . The vacuum molding system of  claim 1 , wherein the casting plate comprises a float glass plate configured to impart a planar surface to a diffuser interface surface of a finished optical wedge. 
     
     
         5 . The vacuum molding system of  claim 4 , wherein the casting plate comprises a surface roughness average of two nanometers or less. 
     
     
         6 . The vacuum molding system of  claim 1 , further comprising an ionizer gun configured to control one or more electrostatic potentials of the vacuum molding system. 
     
     
         7 . The vacuum molding system of  claim 1 , further comprising a precursor-curing energy source. 
     
     
         8 . The vacuum molding system of  claim 7 , wherein the precursor-curing energy source comprises an ultraviolet lamp. 
     
     
         9 . The vacuum molding system of  claim 1 , further comprising a wedge blank inserted in the vacuum molding tool, the wedge blank comprising a smoother surface in contact with the molding surface and a rougher surface opposite the molding surface. 
     
     
         10 . The vacuum molding system of  claim 1 , further comprising a finish layer applied over the wedge blank, wherein the casting surface is in contact with the finish layer. 
     
     
         11 . The vacuum molding system of  claim 1 , wherein the casting surface comprises a mold release agent. 
     
     
         12 . The vacuum molding tool of  claim 1 , wherein the casting plate has a thickness of 20-25 mm. 
     
     
         13 . An optical wedge, comprising:
 a wedge blank comprising a surface having a non-planar shape; and   a cured polymer disposed on a surface of the wedge blank opposite the surface having the non-planar shape, wherein the cured polymer comprises an index of refraction of within +/−0.01 of an index of refraction of the wedge blank, and wherein the cured polymer comprises a cast surface.   
     
     
         14 . The optical wedge of  claim 13 , wherein the cast surface comprises a surface roughness average of two nanometers or less. 
     
     
         15 . The optical wedge of  claim 13 , wherein the cast surface is planar, and wherein the surface having the non-planar shape comprises an aspheric optical feature. 
     
     
         16 . The optical wedge of  claim 13 , wherein the cured polymer comprises poly(methyl methacrylate). 
     
     
         17 . A vacuum molding system for forming an optical wedge from a wedge blank, the vacuum molding system comprising:
 a vacuum pump;   a vacuum molding tool comprising one or more vacuum ports fluidly connected to the vacuum pump, the vacuum molding tool including a molding surface configured to temporarily shape a molded surface of the wedge blank under the urging of a pressure differential generated by the vacuum pump, the molding surface defining an aspheric optical feature; and   a casting plate configured to be retained across a finish layer of the wedge blank opposite from the molded surface of the wedge blank.   
     
     
         18 . The vacuum molding system of  claim 17 , wherein the casting plate comprises a float glass plate. 
     
     
         19 . The vacuum molding system of  claim 17 , wherein the casting plate has a thickness of 20-25 mm. 
     
     
         20 . The vacuum molding system of  claim 18 , further comprising an ionizer gun.