Laser methods for processing electrochromic glass

Abstract

Techniques for laser processing of a workpiece including electrochromic glass or other thin-film devices where one or more layers are sandwiched between two thin-film conductive layers include directing a laser beam from a laser source onto a surface of the workpiece, wherein the laser beam comprises projected light, the projected light having a selected near-infrared wavelength in the range of about 1.4 to about 3 μm. Where the workpiece comprises an electrochromic device including an electrochromic stack disposed between a first transparent conductive layer, distal from the laser source, and a second transparent conductive layer, proximal to the laser source, removing the material includes removing a portion of the second transparent conductive layer and a portion of the electrochromic stack to expose a surface of the first transparent conductive layer without damaging the first transparent conductive layer.

What is claimed is: 
     
         1 . A method of removing material from a workpiece, the method comprising:
 directing a laser beam from a laser source onto a surface of the workpiece, wherein the laser beam comprises projected light, the projected light having a selected near-infrared wavelength in the range of about 1.4 to about 3 μm.   
     
     
         2 . The method of  claim 1 , wherein the workpiece comprises an electrochromic device or a partially fabricated electrochromic device on a transparent substrate, and the material comprises one or more layers of the electrochromic device. 
     
     
         3 . The method of  claim 2 , wherein removing the material produces an ablation region on the one or more layers of the electrochromic device, the ablation region having at least one edge. 
     
     
         4 . The method of  claim 3 , wherein the edge is approximately orthogonal to the one or more layers. 
     
     
         5 . The method of  claim 3 , wherein the edge has a stepped or tapered profile. 
     
     
         6 . The method of  claim 1 , wherein removing the material forms a bus bar pad expose region. 
     
     
         7 . The method of  claim 6 , wherein:
 the workpiece comprises an electrochromic device including an electrochromic stack disposed between a first transparent conductive layer, distal from the laser source, and a second transparent conductive layer, proximal to the laser source; and   removing the material comprises removing a portion of the second transparent conductive layer and a portion of the electrochromic stack to expose a surface of the first transparent conductive layer without damaging the first transparent conductive layer.   
     
     
         8 . The method of  claim 7 , wherein the bus bar pad expose region comprises an exposed portion of the surface of the first transparent conductive layer. 
     
     
         9 . The method of  claim 1 , wherein the selected near-infrared wavelength is within a range of 1.8 μm to 2.2 μm. 
     
     
         10 . The method of  claim 1 , wherein the laser beam removes the material from the workpiece by ablation. 
     
     
         11 . The method of  claim 1 , wherein removing the material does not comprise moving the laser beam in a raster scan. 
     
     
         12 . The method of  claim 1 , wherein the laser source comprises a thulium laser operating at a selected wavelength of about 1.95 μm or a holmium laser operating at a selected wavelength of about 2.05 μm. 
     
     
         13 . The method of  claim 1 , wherein the laser source is configured to deliver a pulsed laser beam, each pulse having an energy in a range of about 0.2 to 1500 mJ. 
     
     
         14 . The method of  claim 13 , wherein each pulse has a duration of from about 1 ns to about 100 ns. 
     
     
         15 . The method of  claim 13 , wherein the pulsed laser beam has a pulse repetition rate of about 1 to 100,000 Hz. 
     
     
         16 . The method of  claim 1 , wherein the workpiece includes a large-area float glass substrate. 
     
     
         17 . The method of  claim 16 , wherein the float glass substrate has a surface area greater than 40 square feet. 
     
     
         18 . A material removal system comprising:
 a laser source configured to direct a laser beam onto a surface of a workpiece, wherein the laser beam comprises projected light, the projected light having a selected near-infrared wavelength the range of about 1.4 to about 3 μm; and   a workpiece holder; wherein:
 the laser source and the workpiece holder are configured such that, during operation, the laser beam ablates material from the workpiece. 
   
     
     
         19 . The system of  claim 18 , wherein the workpiece comprises an electrochromic device or a partially fabricated electrochromic device on a transparent substrate, and the material comprises one or more layers of the electrochromic device. 
     
     
         20 . The system of  claim 19 , wherein removing the material produces an ablation region on the one or more layers of the electrochromic device, the ablation region having at least one edge. 
     
     
         21 . The system of  claim 20 , wherein the edge is approximately orthogonal to the one or more layers. 
     
     
         22 . The system of  claim 20 , wherein the edge has a stepped or tapered profile. 
     
     
         23 . The system of  claim 18 , wherein removing the material forms a bus bar pad expose region. 
     
     
         24 . The system of  claim 23 , wherein:
 the workpiece comprises an electrochromic device including an electrochromic stack disposed between a first transparent conductive layer, distal from the laser source, and a second transparent conductive layer, proximal to the laser source; and   removing the material comprises removing a portion of the second transparent conductive layer and a portion of the electrochromic stack to expose a surface of the first transparent conductive layer without damaging the first transparent conductive layer.   
     
     
         25 . The system of  claim 24 , wherein the bus bar pad expose region comprises an exposed portion of the surface of the first transparent conductive layer. 
     
     
         26 . The system of  claim 18 , wherein the laser source comprises a thulium laser operating at a selected wavelength of about 1.95 μm or a holmium laser operating at a selected wavelength of about 2.05 μm. 
     
     
         27 . The system of  claim 18 , wherein the laser source is configured to deliver a pulsed laser beam, each pulse having an energy in a range of about 0.2 to 1500 mJ. 
     
     
         28 . The system of  claim 27 , wherein each pulse has a duration of from about 1 ns to about 100 ns. 
     
     
         29 . The system of  claim 27 , wherein the pulsed laser beam has a pulse repetition rate of about 1 to 100,000 Hz. 
     
     
         30 . The system of  claim 18 , wherein the workpiece includes a large-area float glass substrate. 
     
     
         31 . A structure comprising:
 a substrate; and   an electrochromic device disposed on the substrate, the electrochromic device including one or more layers configured as an electrochromic stack disposed between a first transparent conductive layer, distal from a laser source, a second transparent conductive layer, proximal to the laser source, and an ablation region; wherein:
 the ablation region is produced by removing a portion of the second transparent conductive layer and a portion of the electrochromic stack without damaging the first transparent conductive layer. 
   
     
     
         32 . The structure of  claim 31 , wherein the ablation region has at least one edge. 
     
     
         33 . The structure of  claim 32 , wherein the edge is approximately orthogonal to the one or more layers. 
     
     
         34 . The structure of  claim 32 , wherein the edge has a stepped or tapered profile. 
     
     
         35 . The structure of  claim 31 , wherein the ablation region comprises a bus bar pad expose region. 
     
     
         36 . The structure of  claim 35 , wherein the bus bar pad expose region comprises an exposed portion of the first transparent conductive layer. 
     
     
         37 . The structure of  claim 31 , further comprising a large-area float glass substrate. 
     
     
         38 . The structure of  claim 37 , wherein the float glass substrate has a surface area greater than 40 square feet. 
     
     
         39 . A method of fabricating an optical device, the method comprising:
 removing material from the optical device by directing a laser beam from a laser source onto a surface of the optical device, the optical device comprising a substrate and an electrochromic stack, the electrochromic stack being disposed between a first transparent conductive layer, distal from the laser source, and a second transparent conductive layer, proximal to the laser source; wherein
 removing the material comprises removing a portion of the second transparent conductive layer and a portion of the electrochromic stack without damaging the first transparent conductive layer; and 
 the laser beam comprises projected light, the projected light having a selected near-infrared wavelength in the range of about 1.4 to about 3 μm. 
   
     
     
         40 . The method of  claim 39 , wherein removing the material produces an ablation region on the electrochromic stack, the ablation region having at least one edge. 
     
     
         41 . The method of  claim 40 , wherein the material comprises one or more layers of the optical device and the at least one edge is approximately orthogonal to the one or more layers. 
     
     
         42 . The method of  claim 40 , wherein the edge has a stepped or tapered profile. 
     
     
         43 . The method of  claim 39 , wherein removing the material forms a bus bar pad expose region. 
     
     
         44 . The method of  claim 43 , wherein the bus bar pad expose region comprises an exposed portion of the surface of the first transparent conductive layer. 
     
     
         45 . The method of  claim 39 , wherein the laser source comprises a thulium laser operating at a selected wavelength of about 1.95 μm or a holmium laser operating at a selected wavelength of about 2.05 μm. 
     
     
         46 . The method of  claim 39 , wherein the laser source is configured to deliver a pulsed laser beam, each pulse having an energy in a range of about 0.2 to 1500 mJ. 
     
     
         47 . The method of  claim 46 , wherein each pulse has a duration of from about 1 ns to about 100 ns. 
     
     
         48 . The method of  claim 46 , wherein the pulsed laser beam has a pulse repetition rate of about 1 to 100,000 Hz.