Non-ablative laser patterning
View Patent ↗A method for processing a transparent substrate includes generating at least one laser pulse having laser parameters selected for non-ablatively changing a conductive layer disposed on the transparent substrate into a non-conductive feature, and directing the pulse to said conductive layer. A protective film may be affixed to a surface of the transparent substrate and need not be removed during the processing of the substrate. After processing, processed areas can be visually indistinguishable from unprocessed areas.
1. A method for processing a transparent substrate, comprising:
generating at least one laser pulse having laser parameters selected for non-ablatively changing a conductive layer, having a thickness of less than 100 nm and including silver nanowires, disposed on said transparent substrate into a non-conductive feature including silver nanowires; and
directing said pulse to said conductive layer;
wherein said laser parameters include a pulse length of less than about 200 ps and a pulse fluence of less than about 1.5 J/cm 2 .
2. The method of claim 1 wherein a spot size of said pulse is varied within a range of 5 to 100 μm by varying the position of the substrate in relation to the incident pulse.
3. The method of claim 1 wherein the transparent substrate includes a protective film disposed on a surface of said substrate opposite from said conductive layer, and which protective film is not removed during the non-ablative processing of said conductive layer.
4. The method of claim 1 wherein the transparent substrate is made of a flexible polyethylene terephthalate material.
5. The method of claim 1 wherein to an unaided eye of an observer said non-conductive feature is visibly indistinguishable as compared to an adjacent unprocessed conductive layer.
6. The method of claim 1 wherein said pulse is directed through said transparent substrate to said conductive layer.
7. The method of claim 1 wherein the surface roughness of the conductive layer is substantially unchanged after processing with said laser pulse.
8. The method of claim 1 wherein said conductive layer becomes non-conductive in the processed area through a selective oxidation mechanism.
9. The method of claim 1 , wherein the silver nanowires of the conductive layer are situated in an organic overcoat.
10. A method for changing the sheet resistance of a conductive matrix of silver nanowires on a flexible transparent substrate, comprising:
generating at least one pulse with laser parameters selected in a range for increasing the sheet resistance of the conductive matrix without ablating the silver nanowires; and
directing the pulse to the conductive matrix to increase said sheet resistance;
wherein the flexible transparent substrate includes a protective film disposed on a surface of the substrate opposite from said conductive matrix of silver nanowires, and which protective film is not removed during the non-ablative processing of said conductive matrix by said laser pulse.
11. The method of claim 10 wherein to an unaided eye of an observer an area processed by a plurality of said laser pulses is visibly indistinguishable as compared to an adjacent unprocessed area.
12. The method of claim 10 , wherein the conductive matrix of silver nanowires includes an organic overcoat.
13. A method for processing a transparent substrate with a pulsed laser beam, the substrate being characterized by having conductive silver nanowires disposed on a selected surface thereof, the conductive silver nanowires capable of experiencing non-ablative change into non-conductive silver nanowires with a pulsed laser beam having selected parameters, said method comprising:
generating at least one laser pulse with said selected parameters; and
directing said pulse to the conductive silver nanowires on the substrate to produce said change into non-conductive silver nanowires;
wherein the conductive silver nanowires are situated in an organic overcoat.
14. The method of claim 13 wherein the transparent substrate includes a protective film disposed on a surface of said substrate opposite from said conductive silver nanowires, and which protective film is not removed during the non-ablative processing of said conductive silver nanowires.
15. The method of claim 13 wherein to an unaided eye of an observer said non-conductive silver nanowires are visibly indistinguishable as compared to unprocessed conductive silver nanowires.
16. The method of claim 13 , wherein said pulse is directed to the conductive silver nanowires on the substrate without directing said pulse to an over-oxidized layer.
17. A method for processing a conductive silver nanowire layer of a flexible transparent substrate with a pulsed laser beam, the conductive silver nanowire layer characterized in that exposure to a laser pulse having selected laser pulse parameters causes the conductive silver nanowires to become non-conductive silver nanowires without ablatively removing the silver nanowire layer, said method comprising:
generating at least one laser pulse which has said selected laser pulse parameters; and
directing said pulse to the conductive silver nanowire layer of the substrate without directing said pulse to an over-oxidized layer.
18. The method of claim 17 wherein the flexible transparent substrate includes a protective film disposed on a surface of said substrate opposite from said conductive silver nanowire layer, and which protective film is not removed during the non-ablative processing of said conductive silver nanowire layer.
19. The method of claim 17 wherein to an unaided eye of an observer said non-conductive silver nanowires formed by the laser pulse are visibly indistinguishable as compared to unprocessed conductive silver nanowires.
20. The method of claim 17 , wherein the conductive silver nanowire layer includes an organic overcoat.