Pitch layer pad for smoothing optical surfaces

Abstract

Methods, apparatus and systems for polishing an optical component having an aspheric or freeform surface are described. In one example aspect, a polishing device includes a solid plate and a container coupled to the solid plate. The container encloses a non-Newtonian material that exhibits a solid-like and a fluid-like behavior based on a frequency of a stress applicable to the non-Newtonian material. The device also includes a layer of viscoelastic polymer adhered to the container to polish the optical component. The layer of viscoelastic polymer comprises one or more segments positioned according to a shape of the solid plate.

A set of example claims include: 
     
         1 . An apparatus for polishing an optical component having an aspheric or freeform surface, comprising:
 a solid back plate,   a container coupled to the solid plate, wherein the container encloses a non-Newtonian material that exhibits a solid-like and a fluid-like behavior based on a stress frequency applicable to the non-Newtonian material; and   a layer of viscoelastic polymer attached or otherwise coupled to the container, the layer of viscoelastic polymer positioned to provide physical contact with the optical component for polishing the optical component, wherein the layer of viscoelastic polymer comprises one or more segments.   
     
     
         2 . The apparatus of  claim 1 , wherein the viscoelastic polymer includes at least one of:
 a residue distilled from tar, oil, or wood;   a rosin;   a beeswax or linseed oil;   an asphalt;   a flake shellac;   a paraffin wax;   a wood flour; or   a walnut shell flour.   
     
     
         3 . The apparatus of  claim 1 , wherein the layer of viscoelastic polymer has a thickness in a range 0.1 mm to 5 mm. 
     
     
         4 . The apparatus of  claim 1 , wherein the layer of viscoelastic polymer further comprises a matrix material to form a compound matrix of viscoelastic polymer. 
     
     
         5 . The apparatus of  claim 4 , wherein the matrix material includes a cloth or a polyurethane matrix. 
     
     
         6 . The apparatus of  claim 1 , wherein the one or more segments of the layer of viscoelastic polymer form multiple channels for facilitating uniform distribution of a polishing compound. 
     
     
         7 . The apparatus of  claim 1 , wherein the one or more segments of the layer of viscoelastic polymer have random or pseudo-random boundaries. 
     
     
         8 . The apparatus of  claim 1 , wherein the one or more segments of the layer of viscoelastic polymer include one or more slices or wedges to form a circular shape. 
     
     
         9 . The apparatus of  claim 1 , wherein the one or more segments of the layer of viscoelastic polymer have a rectangular or square shape. 
     
     
         10 . The apparatus of  claim 1 , wherein the layer of viscoelastic polymer is adhered to the container using a pressure-sensitive adhesive. 
     
     
         11 . The apparatus of  claim 1 , wherein the layer of viscoelastic polymer is adapted to polish a surface having an arbitrary surface profile. 
     
     
         12 . The apparatus of  claim 1 , wherein the layer of viscoelastic polymer causes a smaller displacement of the non-Newtonian material and the polishing pad in polishing a surface protrusion as compared to a polishing arrangement that includes a polyurethane layer for contacting the surface protrusion. 
     
     
         13 . A method for producing a layer of viscoelastic polymer, comprising:
 melting a viscoelastic polymer into a liquid form;   pouring the viscoelastic polymer between multiple substrates, wherein the multiple substrates are separated by a plurality of spacers; and   solidifying the viscoelastic polymer to obtain one or more viscoelastic polymer layers.   
     
     
         14 . The method of  claim 13 , wherein the plurality of spacers has a size in a range of 0.1 mm to 5 mm. 
     
     
         15 . The method of  claim 13 , comprising placing a matrix material between the multiple substrate to form a viscoelastic polymer compound after the viscoelastic polymer solidifies. 
     
     
         16 . The method of  claim 15 , wherein the matrix material includes a cloth or a polyurethane matrix. 
     
     
         17 . The method of  claim 13 , comprising:
 dividing each of the one or more viscoelastic polymer layers into multiple segments.   
     
     
         18 . The method of  claim 17 , wherein the multiple segments have random or pseudo-random boundaries. 
     
     
         19 . The method of  claim 17 , wherein the multiple segments include one or more slices or wedges to form a circular shape. 
     
     
         20 . The method of  claim 17 , wherein the multiple segments have a rectangular or square shape.