Optical Illumination System and Method

Abstract

A system, method, and method of manufacturing directed to an optical device with an efficient optical illumination. The optical illumination can be provided by tilting a light source and using a refractive lens to direct the light onto a surface. Alternatively, the optical illumination can be provided using total internal reflection with a conical light pipe and a curvatured entrance and exit surface.

1 . An illumination system in an optical pointing device comprising: 
 an entrance surface positioned to gather light from a light source positioned at a first angle relative to a target surface;    a light pipe truncated along a first truncation plane, the light pipe coupled to the entrance surface for directing the light gathered from the entrance surface by reflecting at the first truncation plane meeting a total internal reflection condition for the light; and    a curvatured exit surface coupled to the light pipe, the curvatured exit surface directing the light onto the target surface at a second angle relative to the target surface, the second angle different than the first angle.    
   
   
       2 . The system of  claim 1 , wherein a portion of the light pipe is frustro-conical shaped.  
   
   
       3 . The system of  claim 2 , wherein the light pipe has a larger entrance cross-section than an exit cross-section.  
   
   
       4 . The system of  claim 1 , wherein the truncated plane is covered with a metal coating.  
   
   
       5 . The system of  claim 1 , further comprising a second truncated plane for further directing the light toward the exit surface at a third angle relative to the target surface, the third angle different than the second angle.  
   
   
       6 . The system of  claim 5 , wherein the second truncated plane is covered with a metal coating.  
   
   
       7 . The system of  claim 1 , wherein the light source is a light emitting diode.  
   
   
       8 . The system of  claim 1 , wherein the light pipe is made from an optical plastic.  
   
   
       9 . The system of  claim 1 , wherein the truncated light pipe is made from glass.