LASER METHODS FOR PROCESSING ELECTROCHROMIC GLASS
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.
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.