Method for preparing transparent conductive silver patterns
View Patent ↗Electrically-conductive articles are prepared to have electrically-conductive silver metal electrode grids and electrically-conductive silver connector wire patterns (BUS lines) on one or both supporting sides of a transparent substrate. The electrically-conductive silver connector wire patterns are designed with one silver main wire that comprises two or more adjacent silver micro-wires in bundled patterns. These bundled patterns and silver micro-wires are designed with specific dimensions and configurations to provide optimal fidelity (or correspondence) to the mask image used to provide such images in a silver halide emulsion layer. The electrically-conductive articles are provided by imagewise exposure, development, and fixing of corresponding silver halide-containing conductive film element precursors containing photosensitive silver halide emulsion layers. The electrically-conductive articles can be used as parts of various electronic devices including touch screen devices.
1. A method for providing an electrically-conductive article using photosensitive silver halide, the method comprising:
imagewise exposing a conductive film element precursor that comprises a transparent substrate comprising a first supporting side and an opposing second supporting side and a photosensitive silver halide emulsion layer on at least the first supporting side, to radiation to provide, in the photosensitive silver halide emulsion layer on at least the first supporting side: (a) a latent electrically-conductive silver metal electrode grid, (b) a latent electrically-conductive silver connector wire pattern different from the latent electrically-conductive silver metal electrode grid, and optionally, (c) transparent regions outside of both the latent electrically-conductive silver metal electrode grid and the latent electrically-conductive silver connector wire pattern; and
processing the latent electrically-conductive silver metal electrode grid and the latent electrically-conductive silver connector wire pattern using at least solution physical development and silver halide fixing, to provide: (a) an electrically-conductive silver metal electrode grid from the latent electrically-conductive silver metal electrode grid, (b) an electrically-conductive silver connector wire pattern from the latent electrically-conductive silver connector wire pattern, and optionally, (c) transparent regions outside of both the electrically-conductive silver metal electrode grid and the electrically-conductive silver connector wire pattern,
wherein:
(i) the electrically-conductive silver connector wire pattern comprises at least one silver main wire that comprises two or more silver micro-wires that are electrically connected to a silver end wire at an end of the at least one silver main wire, the two or more silver micro-wires and the silver end wire in the at least one silver main wire forming a bundled pattern;
(ii) the average length of each silver micro-wire is at least 1 mm;
(iii) the ratio of the average width of each silver micro-wire to the average distance between two adjacent silver micro-wires in each bundled pattern is at least 0.5:1 but less than 2:1;
(iv) the electrically-conductive silver connector wire pattern has an integrated transmittance of less than 68%; and
(v) for each silver micro-wire, the ratio of maximum height to minimum height is at least 1.05:1.
2. The method of claim 1 , wherein the electrically-conductive silver connector wire pattern comprises at least two adjacent silver main wires, and the average distance between the at least two adjacent silver main wires is greater than the average distance between any two adjacent silver micro-wires in each bundled pattern.
3. The method of claim 2 , wherein the average distance between any two adjacent silver micro-wires in each bundled pattern is at least 2 μm and up to and including 10 μm.
4. The method of claim 1 , wherein the conductive film element precursor further comprises a photosensitive silver halide emulsion layer disposed on the opposing second supporting side of the transparent substrate, and
the method further comprising:
imagewise exposing the photosensitive silver halide emulsion layer on the opposing second supporting side of the transparent substrate to provide (a) an opposing latent electrically-conductive silver metal electrode grid, (b) an opposing latent electrically-conductive silver connector wire pattern different from the opposing latent electrically-conductive silver metal electrode grid, and optionally, (c) transparent regions outside of both the opposing latent electrically-conductive silver metal electrode grid and the opposing latent electrically-conductive silver connector wire pattern; and
processing the opposing latent electrically-conductive silver metal electrode grid and the opposing latent electrically-conductive silver connector wire pattern using at least solution physical development and silver halide fixing, to provide: (a) an opposing electrically-conductive silver metal electrode grid from the opposing latent electrically-conductive silver metal electrode grid, (b) an opposing electrically-conductive silver connector wire pattern from the opposing latent electrically-conductive silver connector wire pattern, and optionally, (c) transparent regions outside of both the opposing electrically-conductive silver metal electrode grid and the opposing electrically-conductive silver connector wire pattern on the opposing second supporting side of the transparent substrate,
wherein, on the opposing second supporting side of the transparent substrate:
(i) the opposing electrically-conductive silver connector wire pattern comprises at least one silver main wire that comprises two or more silver micro-wires that are electrically connected to a silver end wire at an end of the at least one silver main wire, the two or more silver micro-wires and the silver end wire in the at least one silver main wire forming a bundled pattern;
(ii) the average length of each silver micro-wire is at least 1 mm;
(iii) the ratio of the average width of each silver micro-wire to the average distance between two adjacent silver micro-wires in each bundled pattern is at least 0.5:1 but less than 2:1;
(iv) the opposing electrically-conductive silver connector wire pattern has an integrated transmittance of less than 68%; and
(v) for each silver micro-wire, the ratio of maximum height to minimum height is at least 1.05:1.
5. The method of claim 4 , wherein the opposing electrically-conductive silver connector wire pattern comprises at least two adjacent silver main wires, and the average distance between the at least two adjacent silver main wires is greater than the average distance between any two adjacent silver micro-wires in each bundled pattern.
6. The method of claim 4 , wherein the average distance between any two adjacent silver micro-wires in each bundled pattern on the opposing second supporting side of the transparent substrate is at least 2 μm and up to and including 10 μm.
7. The method of claim 4 , wherein imagewise exposing and processing of the photosensitive silver halide emulsion layer on the opposing second supporting side of the transparent substrate are carried out simultaneously with imagewise exposing and processing of the photosensitive silver halide emulsion layer on the first supporting side of the transparent substrate.
8. The method of claim 1 , wherein for each silver micro-wire, the ratio of maximum height to minimum height is at least 1.1:1.
9. The method of claim 1 , wherein at least one silver micro-wire has a maximum height that is the same as its center height.
10. The method of claim 1 , wherein at least one silver micro-wire has a maximum height that is closer to its outer edge than to its center height.
11. The method of claim 1 , wherein each silver micro-wire has a ratio of maximum height to average height of at least 1.05:1.
12. The method of claim 1 , wherein the average width of each silver micro-wire is at least 5 μm and up to and including 20 μm.
13. The method of claim 1 , wherein each bundled pattern comprises at least one silver cross-wire between adjacent silver micro-wires that is not at the end of the adjacent silver micro-wires.
14. The method of claim 1 , wherein each bundled pattern comprises multiple silver cross-wires between adjacent silver micro-wires, wherein the multiple silver cross-wires are arranged at a distance from each other of at least 100 μm.
15. The method of claim 1 , wherein each bundled pattern comprises multiple silver cross-wires in a set of adjacent silver micro-wires that are offset from multiple silver cross-wires in an adjacent set of adjacent silver micro-wires.
16. The method of claim 14 , wherein each of the multiple silver cross-wires is substantially perpendicular to the adjacent silver micro-wires.
17. The method of claim 1 , wherein the average distance between any two adjacent silver main wires is greater than the average distance between any two adjacent silver micro-wires in each bundled pattern by at least 30%.
18. The method of claim 1 , wherein the ratio of the average width of each silver micro-wire to the average distance between two adjacent silver micro-wires in each bundled pattern is at least 1:1 and up to and including 2:1.
19. The method of claim 1 , wherein the electrically-conductive silver connector wire pattern has an integrated transmittance of less than 50% and the electrically-conductive silver metal electrode grid has an integrated transmittance of at least 90%.
20. The method of claim 4 , wherein the opposing electrically-conductive silver connector wire pattern has an integrated transmittance of less than 50% and the opposing electrically-conductive silver metal electrode grid has an integrated transmittance of at least 90%.