Method for manufacturing a directionally dependent reflective surface

Abstract

A method for manufacturing a directionally dependent reflective surface on a substantially cylindrical body ( 1 ). The method comprising the engagement of a tool ( 4 ) with the outside surface ( 8 ) of the body, thereby forming at least one groove ( 23 ) therein with a cross section, when measured parallel to the longitudinal axis ( 2 ) of the body, that is asymmetric and wherein the groove is formed without removal of material from the body.

1 . A method for manufacturing a directionally dependent reflective surface on a substantially cylindrical body, said method comprising the engagement of a tool with the outside surface of said body, thereby forming at least one groove therein with a cross section when measured parallel to the longitudinal axis of said body that is asymmetric, wherein said groove is formed without removal of material from said body.  
   
   
       2 . A method for manufacturing a directionally dependent reflective surface on a substantially cylindrical body as claimed in  claim 1 , wherein said method further comprises said tool relatively moving along said outside surface in a direction parallel to the longitudinal axis of said cylindrical body whilst said cylindrical body is rotated relative to said tool, thereby imparting a helical path to said tool relative to said body and hence forming said at least one groove as a helical groove.  
   
   
       3 . A method for manufacturing a directionally dependent reflective surface on a substantially cylindrical body as claimed in  claim 1 , wherein said outside surface of said body is made of stainless steel or nickel silver.  
   
   
       4 . A method for manufacturing a directionally dependent reflective surface on a substantially cylindrical body as claimed in  claim 1 , wherein the tool engages with said outside surface of said body to a depth in the range of 20-200 um.  
   
   
       5 . A method for manufacturing a directionally dependent reflective surface on a substantially cylindrical body as claimed in  claim 2 , wherein said body is rotated at an angular velocity in the range of 20-200 revs/min.  
   
   
       6 . A method for manufacturing a directionally dependent reflective surface on a substantially cylindrical body as claimed in  claim 2 , wherein said tool is relatively moved along said outside surface at a feed rate in the range of 20-200 um/rev.  
   
   
       7 . A method for manufacturing a directionally dependent reflective surface on a substantially cylindrical body as claimed in  claim 2 , wherein said body has a diameter in the range of 20-80 mm  
   
   
       8 . A method for manufacturing a directionally dependent reflective surface on a substantially cylindrical body as claimed in  claim 1 , wherein said method comprises rotating said body whilst said tool is held axially stationary relative to said body.