Optical device polishing

Abstract

Embodiments described herein provide methods for manufacturing an optical device having shaped sidewalls. A substrate material can be shaped to form a substrate portion of an optical device comprising an exit face and sidewalls positioned and shaped to reflect light to the exit face to allow light to escape the exit face. The sidewalls can be polished to a desired degree of polish. Polishing can be done using a polishing tool, etching, particle jet polishing or other polishing method.

1 . A method of manufacturing an optical device comprising:
 providing a substrate material shaped to form an unpolished substrate portion of an optical device;   polishing the unpolished substrate portion of the optical device to a selected degree of polish to form a substrate portion comprising:
 an interface with a non-substrate layer adapted to receive light generated in a light emitting region of the optical device; 
 an exit face that has at least 70% of a minimum area necessary to conserve radiance for a desired half-angle of light projected from the optical device, wherein the exit face is a select distance from the interface; 
 a set of sidewalls, each sidewall positioned and shaped to cause at least a majority of rays having a straight transmission path from the interface to that sidewall to reflect to the exit face with an angle of incidence at the exit face at less than or equal to a critical angle at the exit face. 
   
   
   
       2 . The method of  claim 1 , wherein polishing the set of sidewalls comprises:
 providing an abrasive slurry;   vibrating a polishing tool at ultrasonic frequency to cause the abrasive slurry to remove the substrate material in multiple rows.   
   
   
       3 . The method of  claim 2 , wherein the substrate material is shaped to form substrate portions of multiple optical devices arranged in rows with channels between the rows and wherein polishing the sidewalls further comprises vibrating a shaped polishing tool along the channels. 
   
   
       4 . The method of  claim 2 , wherein the polishing tool comprises a polishing wand and vibrating the polishing tool comprises vibrating the polishing wand at an ultrasonic frequency. 
   
   
       5 . The method of  claim 4 , wherein the substrate material is shaped to form substrate portions of multiple optical devices arranged in rows with channels between the rows and wherein polishing the sidewalls further comprises polishing the sidewalls for optical devices along a row at a set of fixed angles tangential to the sidewalls. 
   
   
       6 . The method of  claim 4 , wherein the substrate material is shaped to form substrate portions of multiple optical devices arranged in rows with channels between the rows and wherein polishing the sidewalls further comprises sweeping the wand through a range of angles as the polishing wand polishes one or more select sidewalls. 
   
   
       7 . The method of  claim 1 , wherein polishing further comprises removing the substrate material using a particle jet. 
   
   
       8 . The method of  claim 1 , further comprising:
 mounting a wafer comprising the substrate material in a tool; and   protecting portions of the wafer to prevent damage to those portions during polishing.   
   
   
       9 . The method of  claim 1 , further comprising mounting the wafer comprising the substrate material to a support structure. 
   
   
       10 . The method of  claim 1 , wherein polishing further comprises using reactive ion etching to polish. 
   
   
       11 . A method of polishing an LED comprising:
 providing a set of unpolished substrate portions of optical devices shaped from a wafer;   polishing the set of unpolished substrate portions with a polishing tool to desired degree of polish to form a set of substrate portions, each substrate portion comprising:
 an exit face opposite from and a distance from an interface an interface with a non-substrate layer adapted to receive light generated in a light emitting region of the optical device, the exit face having at least 70% of a minimum area necessary to conserve radiance for a desired half-angle of light projected from the shaped substrate; and 
 a set of sidewalls, wherein each sidewall is positioned and shaped so that at least a majority of rays having a straight transmission path from the interface to that sidewall reflect to the exit face with an angle of incidence at the exit face of less than or equal to a critical angle at the exit face. 
   
   
   
       12 . The method of  claim 11 , wherein polishing each set of unpolished sidewalls to a desired degree of polish comprises polishing each sidewall to have a roughness average of less than or equal to fifty nanometers. 
   
   
       13 . The method of  claim 11  wherein the polishing tool comprises a polishing wand, the method further comprising:
 (a) vibrating the polishing wand tangential to one or more sidewalls at a select angle to polish the one or more sidewalls;   (b) moving the polishing wand to a number of additional positions along the channel to polish one or more additional sidewalls at the same angle; and   (c) repeating steps (a)-(b) at a select number of additional angles to polish the one or more sidewalls and one or more additional sidewalls at the additional angles.   
   
   
       14 . The method of  claim 11 , wherein the polishing tool comprises a polishing wand, the method further comprising:
 (a) positioning the polishing wand at a position along a select channel;   (b) vibrating the polishing wand to polish one or more sidewalls;   (c) sweeping the polishing wand through a range of angles as the polishing wand polishes the one or more sidewalls;   (d) repeating steps (a)-(c) at a select number of additional positions along the selected channel.   
   
   
       15 . The method of  claim 11 , further comprising introducing an abrasive slurry between the polishing tool and the substrate material. 
   
   
       16 . The method of  claim 15 , wherein introducing the abrasive slurry comprises coating each unpolished substrate portion with the abrasive slurry. 
   
   
       17 . The method of  claim 15 , wherein the abrasive slurry comprises abrasive particles having an average size of less than 10 micrometers. 
   
   
       18 . The method of  claim 17 , wherein the abrasive particles are 5-30% of the abrasive slurry. 
   
   
       19 . The method of  claim 11 , wherein the polishing tool is at least partially formed from a liquid crystal polymer.