WO2012103285A2

WO2012103285A2 - Methods and systems for generating a substantially transparent and conductive substrate

Info

Publication number: WO2012103285A2
Application number: PCT/US2012/022650
Authority: WO
Inventors: Gregory Jablonski; Chris WARGO; Michael Mastropietro
Original assignee: Pchem Associates, Inc.
Priority date: 2011-01-29
Filing date: 2012-01-26
Publication date: 2012-08-02
Also published as: WO2012103285A3

Abstract

Methods and systems for printing a conductive ink onto a substrate to generate a transparent and conductive substrate can include an apparatus for printing ink onto a substrate. The ink can be printed or deposited onto the substrate in a pattern and using any compatible print method. In some embodiments, the ink pattern can be designed to control the conductivity and transparency of the substrate.

Description

METHODS AND SYSTEMS FOR GENERATING A SUBSTANTIALLY

TRANSPARENT AND CONDUCTIVE SUBSTRATE

FIELD OF THE DISCLOSURE

[0001] The below disclosure describes methods and systems for manufacturing a substantially transparent and conductive substrate.

BACKGROUND OF THE DISCLOSURE

[0002] Manufacturing methods for creating a transparent, conductive substrate include depositing a transparent conductor such as indium tin oxide (ITO) on a substrate to create a conductive surface. ITO's conductive and transparent properties permit the creation of a substrate that is not only conductive, but that can maintain up to ninety five percent of the visual light transmission (%VLT) after deposition of ITO on the substrate. Methods for depositing ITO on a substrate can include sputter deposition, vapor deposition or other similar deposition methods. In some instances, ITO can be patterned on a substrate. In these instances, general methods for creating a pattern of conductive geometries can include depositing the ITO on a substrate and scoring or otherwise etching a pattern onto the substrate. Other transparent and conductive oxides may be used, e.g. aluminum zinc oxide (AZO).

[0003] Using transparent, conductive oxides to manufacture substantially transparent, conductive substrates can be costly, difficult, and may produce a brittle substrate. The deposition methods used to deposit the transparent conductor are often process intensive, expensive and cannot be carried out in high volumes. Additionally, the conductive and structural integrity of substrates generated using ITO or other transparent conductors can be diminished when the substrate is folded or otherwise physically manipulated. The decrease or complete loss in integrity can be largely attributed to the brittle nature of the metal oxide. Methods, systems and compositions are therefore needed to generate a rugged and flexible, conductive, transparent substrate using a conductor other than ITO or similar conductive oxides. These methods, systems and compositions may use a conductive ink that can be deposited using a deposition method that allows direct patterned deposition and that can be performed inexpensively at high volumes.

[0004] There exist methods for depositing conductive inks on a substrate in a pattern such that the resulting structure appears to be substantially transparent. Typically the resulting structure, although substantially transparent, contains geometric areas of conductor that are visible to the human eye. Thus, the resulting structure approaches transparency but is not truly transparent because it contains trace amounts of conductor that may be visible to the human eye. Reducing the amount of conductor deposited onto the substrate can affect the conductivity of the substrate and in this way the conductive and optical properties of the patterned surface can be tailored to various applications.

[0005] In embodiments where print plates are used to print a conductor onto a substrate by a relief print method, side printing, ghosting or drag-out can occur. Conductors are often printed onto a substrate in a shape, e.g. a line. Side printing can affect the dimensions of the printed shape because side printing causes the width or the length of the shape to be larger than the surface area of the plate that comes into contact with the substrate. This occurs when the pressure placed on the plate to cause a conductor to transfer from the plate to the substrate, causes additional conductor located on the side of the plate to also transfer to the substrate. Thus, the size of the shape cannot be accurately controlled because an unknown amount of conductor may transfer from the side of the plate to the substrate.

[0006] Methods, systems and compositions are therefore needed for depositing a conductive solution onto a substrate in a pattern such that substantially the same amount of conductor is deposited onto the substrate while maintaining the transparency of the substrate by controlling the size and shape of the pattern.

SUMMARY OF THE DISCLOSURE

[0007] In one aspect, described herein are methods and systems for depositing an ink onto a substrate in a pattern. The pattern can be an ordered or disordered pattern and can comprise any type of geometric area. In some embodiments, the ink can be deposited in any pattern using any print method. The print method can be a flexographic print method, a letterpress print method, any relief print method, or any combination thereof. Once the ink is deposited in a pattern on the substrate, the ink can be cured to form a substantially transparent substrate that is conductive.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The summary, as well as the following detailed description, is further understood when read in conjunction with the appended drawings. For the purpose of illustrating the methods, systems and structures described herein, there are shown in the drawings exemplary embodiments. These drawings, however, are not intended to limit the present disclosure to the specific methods, compositions, and devices disclosed. In addition, the drawings are not necessarily drawn to scale. In the drawings:

[0009] FIG. 1 A depicts a transmission electron microscope ("TEM") micrograph of one embodiment of silver nanoparticles;

[0010] FIG. IB illustrates an embodiment of a scanning electron microscope ("SEM") micrograph of a trace comprised of a composition of the metallic nanoparticles described herein cured for up to 1 minute at 100 degrees Celsius;

[0011] FIG. 1C depicts a SEM micrograph of a trace comprised of a composition of the present disclosure cured for up to 3 minutes at 85 degrees Celsius;

[0012] FIGs. 2A-2C depict embodiments of a plate used to print metallic

nanoparticles onto a substrate;

[0013] FIGs. 3A-3C depict embodiments of a substrate having a conductive ink printed thereon;

[0014] FIGs. 4A-4B illustrate embodiments of methods for printing an ink onto a substrate.

DETAILED DESCRIPTION

[0015] The methods, systems and apparatus described herein are not limited to the specific devices, methods, applications, conditions or parameters described and/or shown herein. Furthermore, the terminology used herein is for the purpose of describing particular embodiments by way of example only and is intended to describe not limit. Also, as used in the specification including the appended claims, the singular forms "a," "an," and "the" include the plural, and reference to a particular numerical value includes at least that particular value, unless the context clearly dictates otherwise. The term "plurality", as used herein, means one or more. When a range of values is expressed, another embodiment includes from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent "about," it will be understood that the particular value forms another embodiment. All ranges are inclusive and combinable.

[0016] It is to be appreciated that certain features of the methods, systems and structures described herein are described in the context of separate embodiments, and may be provided in any combination or sub-combination of the embodiments described herein.

Furthermore, any reference to values stated in ranges includes each and every value within that range. Terms

[0017] As used herein, "mil" means 1/1000 of an inch. 1 mil is also equivalent to 25.4 micrometers.

[0018] As used herein, "sheet resistance" means the electrical resistance divided by the number of squares.

[0019] As used herein, "square" means the length of a conductive film or layer of known dimension divided by the width of the conductive film or layer of known dimension.

[0020] As used herein, the term "mohms" refers to milli ohms, or 1/1000. sup.th ohm.

[0021] As used herein, the term "aqueous" means containing water. In some embodiments, the term "aqueous" refers to a solution comprised substantially entirely of water. In other embodiments, the term "aqueous" can refer to a solution comprised substantially entirely of water and containing limited amounts of additives that adjust either the rheology of the ink or the ability of the ink to bind to a substrate.

[0022] As used herein, the term "bonding" means covalently bonding, ionically bonding, hydrogen bonding, coordinate bonding, and the like.

[0023] As used herein, the term "tail" means a straight, branched, or cyclic chain of carbon atoms, wherein the chain may be aliphatic, and wherein the chain may have one or more additional groups bound to one or more of its member carbon atoms. An example would be a chain of aliphatic carbon atoms with an alcohol group attached to one of the chain members.

[0024] As used herein, the term "hetero atomic head group" means a group including at least one atom wherein at least one atom within the group is atom other than carbon.

Examples include nitrogen, sulfur, or oxygen.

[0025] As used herein, the term "cohesive" means united as a single entity and resisting separation.

[0026] As used herein, the term "complexing" means forming coordinating bonds with a metal atom or ion.

[0027] As used herein, the term "ligand" means a molecule or a molecular group that binds to another chemical entity to form a larger complex. Examples include a molecular group that becomes bound to a metal or metal ion by a coordinate covalent bond through donating electrons from a lone electron pair of the ligand into an empty metal electron orbital.

[0028] As used herein, the term "agglomeration" means two or more particles reversibly clustered together, wherein the surfaces of the particles do not come into contact with one another. [0029] As used herein, the term "floe" means two or more particles reversibly clustered together, wherein the surfaces of the particles do not come into contact with one another.

[0030] As used herein, the term "bulk resistivity" means the inherent resistivity of a material that makes up a specified object. For example, the bulk resistivity of an ingot made of silver would be the inherent conductivity of silver. As another example, the bulk resistivity of an ingot made of an alloy comprising silver and gold would be the inherent conductivity of the silver and gold alloy.

[0031] As used herein, the terms "aggregate", "aggregation", and similar forms mean a unified structure comprised of two or more particles irreversibly fused, connected, or necked together.

[0032] As used herein, "corresponding metal" means the metal or metals that comprise an object or objects.

[0033] As used herein, "side printing" can refer to the additional ink deposited on a substrate when a plate comprising a geometric relief is used to apply the ink to the substrate. Side printing can also be referred to as ghosting or drag-out.

[0034] For purposes of reading the description of the various embodiments below, the following descriptions of the sections of the specification and their respective contents may be helpful:

Section A describes synthesized metallic nanoparticles;

Section B describes a print process and apparatus; and

Section C describes post process methods.

Section A: Metallic Nanoparticles

[0035] Illustrated in Figures 1A-1C are metallic nanoparticles, such as the metallic nanoparticles that can be used to create cohesive metallic shielding structures. In one embodiment, the metallic nanoparticles can comprise at least one silver nanoparticle. In other embodiments, the metallic nanoparticles can comprise any combination of the following compositions or elements: copper; gold, zinc; cadmium; palladium; iridium;

ruthenium; osmium; rhodium; platinum; aluminum; iron; nickel; cobalt; indium; silver oxide; copper oxide; gold oxide; zinc oxide; cadmium oxide; palladium oxide; iridium oxide;

ruthenium oxide; osmium oxide; rhodium oxide; platinum oxide; iron oxide; nickel oxide; cobalt oxide; indium oxide; or any other conductive metal or metal oxide suitable for the methods and structures described herein. [0036] The metallic nanoparticles, in some embodiments, can have an average particle size of less than about 100 nm. In other embodiments, the metallic nanoparticles can have an average particle size of less than about 50 nm. In still other embodiments, the metallic nanoparticles can have an average particle size within the range of 50 nm to 75 nm, while in other embodiments the nanoparticles can have an average particle size within the range of 75 nm to 100 nm. The metallic nanoparticles, in some embodiments, can have an average particle size within the range of 15 nm to 50 nm. While in some embodiments, the metallic nanoparticles can have an average particle size within the range of 30 nm to 50 nm.

[0037] The metallic nanoparticles, in one embodiment, can have an average cross- sectional dimension in a range of about 1 nm to about 100 nm. These metallic nanoparticles, in some embodiments, can comprise at least one ligand bound to its surface, where the ligand can include a heteroatom head group bound to the nanoparticle surface and a tail bound to the heteroatom head group.

[0038] In some embodiments, the metallic nanoparticles can be substantially spherical in shape, while in other embodiments the nanoparticles can be any of the following shapes: kidney-shaped; circular; triangular; rectangular; trapezoidal; typaniform; or any other suitable shape. In some embodiments, each nanoparticle within a plurality or population of metallic nanoparticles can have a substantially uniform shape. In other embodiments, each

nanoparticle within a plurality or population of metallic nanoparticles can have a substantially uniform size.

[0039] In some embodiments, a plurality of nanoparticles or nanoparticle population can include particle agglomerates that include two or more individual nanoparticles. In other embodiments, a plurality of nanoparticles can include a nanoparticle floe that includes two or more individual nanoparticles. In other embodiments, a plurality of nanoparticles can include any combination of particle agglomerate and a nanoparticle floe.

[0040] In some embodiments, the ratio by weight of the population of individual metallic nanoparticles to particle agglomerate can be within a range of about 1 :99 to 99: 1. In other embodiments, the ratio, by weight, of the population of individual metallic

nanoparticles to particle floe can be in the range of from about 1 :99 to 99: 1. A nanoparticle agglomerate or floe can have an average cross-sectional dimension in the range of from about 100 nm to about 10,000 nm. Individual metallic nanoparticles within the nanoparticle agglomerate or floe can comprise any of the above-described compositions or elements. In particular, the individual metallic nanoparticles can comprise silver nanoparticles. In other embodiments, the individual nanoparticles can comprise any combination of the following: silver, copper, gold, zinc, cadmium, palladium, iridium, ruthenium, osmium, aluminum, rhodium, platinum, iron, nickel, cobalt, indium, silver oxide, copper oxide, gold oxide, zinc oxide, cadmium oxide, palladium oxide, iridium oxide, ruthenium oxide, osmium oxide, aluminum oxide, rhodium oxide, platinum oxide, iron oxide, nickel oxide, cobalt oxide, and indium oxide.

[0041] In some embodiments, the metallic nanoparticles can be present within a composition in the range of from about 0.5 wt % to about 70 wt %. Ligand can be present in the range of from about 0.5 wt % to about 75 wt %, and the medium is present in the range of from about 30 to about 98 wt %. The medium, in some embodiments, is an aqueous solution comprising water.

[0042] A composition can be formed from the metallic nanoparticles and an aqueous solution such as any of the aqueous solutions described herein. In some embodiments, the composition can be capable of forming a cohesive structure of less than about 10 micrometers in thickness formed when the metallic nanoparticles are heated at a low temperature. This low temperature, in some embodiments, can be a temperature of less than about 140 degrees Celsius. To create the cohesive structure, the metallic nanoparticles are heated at the low temperature for a period of time less than about 60 seconds. The resulting cohesive shielding structure, in some embodiments, can have a resistivity in the range of from about 2 times to about 15 times the bulk resistivity of the corresponding metal used in the metallic

nanoparticle composition.

[0043] A continuous network film is created once the metallic nanoparticles are heated at a low temperature. The low temperature can be a temperature less than about 140 degrees Celsius. This film can form any number of shapes, marks, lines, figures and can occupy an area having various dimensions and configurations. In some embodiments, the nanoparticles, when heated, do not create a monolayer but rather an agglomerate of nanoparticles. Furthermore, the nanoparticles, when heated, can form a continuous porous network of cured nanoparticles. The network, in some embodiments, can be referred to as a matrix, network, web, grid or pattern of cured metallic nanoparticles.

Section B: Print Process and Apparatus

[0044] Illustrated in Figure 2A is a side-view of an embodiment of a plate 200 that can be used to deposit or print a conductive ink onto a substrate. The plate 200 can have a top 205 and a bottom 210 where at least a portion of the plate top 205 physically makes contact with a substrate for the purpose of depositing a conductive ink onto the substrate. In general, the plate 200 can be a plate 200 for any relief print method. In some embodiments, the plate 200 can be a plate 200 used in flexographic print methods, in other embodiments the plate 200 can be a plate 200 used in letterpress print methods.

[0045] The plate 200 can be manufactured from any material suitable for receiving a conductive substance. The plate bottom 210, in some embodiments, can comprise structures for attaching the plate 200 to a machine that can be used to apply the plate 200 to a substrate. The machine can be any machine capable of physically moving the plate 200 in any number of directions relative to a surface. In some embodiments, the machine can cause the plate 200 to make contact with a substrate and can further cause the plate 200 to apply pressure to the substrate. While in some embodiments, the top of the plate 205 makes contact with a substrate; in other embodiments the sides of the plate 200 may also make contact with a substrate. The top of the plate 205 can be considered the portion of the plate 200 located vertically parallel to the portion of the plate 200 that connects to a machine able to manipulate the position of the plate 200.

[0046] A plate 200 can be used to apply, deposit or print a conductive ink onto a substrate. The top portion of the plate 205 can be used to apply, deposit or print the conductive ink onto the substrate. An ink can be applied to or secreted from the top portion of the plate 205 such that the plate top 205 comprises a layer of ink. Once the ink is applied to a substrate, the ink can be cured to create a conductive geometry. The plate top 205 can then make contact with a substrate so as to cause at least a portion of the ink to transfer from the plate top 205 to the substrate. In some embodiments, causing the plate top 205 to physically connect with the substrate can include causing the plate top 205 to apply a predetermined amount of pressure to the substrate. When the plate top 205 physically connects with the substrate, in some embodiments a predetermine amount of ink transfers from the plate top 205 to the substrate. The amount of ink transferred to the substrate, in some embodiments, can be directly proportional to the amount of pressure the plate top 205 applies to the substrate.

[0047] Illustrated in Figure 2B is a top view of an embodiment of a plate 200 that can be used to apply, deposit or print a conductive ink onto a substrate. The plate top 205 can comprise a geometric relief 240 that can begin at the plate edge 235 and can span the length of the plate 200. The geometric relief 240 can include geometric elements 215 spaced apart by a predetermined length 220 and overlapping by a predetermined length 230. In some instances, the geometric elements 215 can include edges 225 that are horizontally parallel with the length of the plate 200. [0048] Further referring to Figure 2B, and in more detail, in some embodiments the plate top 205 can comprise a geometric relief 240. This relief 240 can extend vertically from the surface of the plate top 205 a predetermined length. In some embodiments, the relief 240 can be generated by eliminating a portion of the surface of the plate top 205. In other embodiments, the relief 240 can be a separate structure affixed to the plate top 205. The relief 240 can span substantially the entire length of the plate 200; while in other

embodiments the relief 240 can span a portion of the length of the plate 200. In some embodiments, the geometric relief 240 can be uniformly distributed over the surface of the plate top 205. In other embodiments the geometric relief 240 can be sporadically distributed over the surface of the plate top 205.

[0049] Included within the geometric relief 240 can be one or more geometric elements 215. These geometric elements 215 can be the same size and shape, while in other embodiments the geometric elements 215 can vary in size and shape. While Figure 2B illustrates a plate having a geometric relief 240 comprising diamond-shaped geometric elements 215, the geometric elements 215 can be any of the following shapes or forms:

circular; open circles; closed circles; dots; oval; rectangular; square; triangular; trapezoidal; pentagonal; octagonal; polygonal; hexagonal; elliptical; reniform; or any other shape or form. In some embodiments, the geometric elements 215 can be a non-symmetrical shape. The shape of the geometric elements 215 can vary throughout the length of the geometric relief 240. In some embodiments, the geometric relief 240 can include more than one geometric element 215, while in other embodiments the geometric relief 240 can include a single geometric element 215. The shapes can be open or closed such that the ink shape transferred to the substrate is a dot. In some embodiments the dot can be circular, while in other embodiments the dot can be any shape described herein.

[0050] Each geometric element 215, in some embodiments, can be separated by a predetermined length 220. This length can span from the center of on geometric element 215 to the center of an adjacent geometric element 215. In some embodiments the length 220 between geometric elements 215 can be substantially uniform throughout the length of the relief 240. In other embodiments, the length 220 between geometric elements 215 can vary throughout the length of the relief 240.

[0051] Each geometric element 215, in some embodiments, can overlap by a predetermined length 230. This length can extend from the overlapping edge of one geometric element 215 to the overlapping edge of an adjacent geometric element 215. In some embodiments, the overlap length 230 can directly affect the number of geometric elements included in the geometric relief 240. In these embodiments, the number of geometric elements can further affect the number of geometric element edges 225 that span the length of the plate 200. Each geometric element edge 225 extends vertically from the surface of the plate top 205, and has a surface that is parallel to the side of the plate 200.

[0052] Illustrated in Figure 2C is a perspective view of an embodiment of a plate 200 having a geometric relief 240 installed on the top of the plate 205. The perspective view illustrates the geometric relief 240 extending vertically from the plate top 205. In some embodiments, the geometric relief 240 can extend vertically a predetermined distance 245.

[0053] Illustrated in Figures 3A-3C are embodiments of a substrate 300 having a conductive ink printed thereon in a pattern. Each of Figures 3A-3C illustrates a different pattern 305, 310 and 315. While Figures 3A-3C illustrate three different types of patterns, other patterns can be used. In some embodiments, the pattern printed on the substrate 300 can be symmetrical, while in others the pattern is not symmetrical.

[0054] Further referring to Figures 3A-3C, the substrate 300 can be any substrate described herein. In some embodiments the substrate 300 can be a thin film of polyester, in other embodiments the substrate 300 can be a conductive or non-conductive polymer. In other embodiments, the substrate can be any plastic film like PET with a continuous coating applied thereon that improves the wettability of the conductive ink onto the substrate. In some embodiments, each pattern contains one or more deposited, applied or printed conductive areas. These areas can be formed by applying the top of the plate 200 illustrated in Figures 2A-2C to the substrate 300. Applying the top of the plate 205 can include using any mechanical means necessary to cause the substrate 300 to come into contact with the top of the plate 205. In some embodiments, the portion of the plate 200 that comes into contact with the substrate 300 can be a geometric relief 240 or relief spanning at least a portion of the surface area of the plate top 205. The relief 240 can comprise any pattern and in some embodiments can be any relief 240 described herein.

[0055] When the substrate 300 comes into contact with the plate 200, the ink distributed over the surface area of the plate top 205 can transfer from the top of the plate 205 to the substrate 300. In some embodiments, this transfer can be accomplished by applying pressure to either the plate 200 or the substrate 300. Applying pressure can cause the sides of the plate 200 to also make contact with the substrate 300 such that side -printing occurs. When this occurs, the shape created by the transferred ink can have measurements larger than the surface area of the top of the plate 205. For example, if the surface area of the top of the plate has a width of 25 microns, side-printing can cause the shape of ink transferred to the substrate to have a width of 30 microns.

[0056] Illustrated in Figure 3A is one embodiment of a pattern of ink deposited on a substrate 300. The pattern in Figure 3 A comprises one or more circular areas 305. In some embodiments, the width of the circles' 305 lines can be within a range of 25 to 10 microns. The circular areas 305 can be placed throughout the surface of the substrate 300 in any ordered or non-ordered pattern. In some embodiments the circular areas 305 can be closed such that the entire area is filled with ink, in other embodiments the circular areas 305 can be open such that the areas are rings. The diameter of the circular areas 305 can vary or can be uniform and can be any size. In some embodiments, the diameters of the circular areas 305 and the width of the ring that defines the circular areas can be predetermined values. These values can be chosen such that the resulting pattern causes the substrate 300 to be conductive and substantially transparent.

[0057] Illustrated in Figure 3B is another embodiment of a pattern of ink deposited on a substrate 300. The pattern in Figure 3B comprises a grid pattern 310 created by depositing a series of horizontal lines and a series of vertical lines. In some embodiments, the lines of the grid pattern 310 can have a width within a range of 5 to 75 microns. While Figure 3B illustrates a grid pattern having vertical lines that are parallel with the side edges of the substrate 300 and horizontal lines that are parallel with the top and bottom edges of the substrate 300, in other embodiments the grid pattern 310 can be oriented in any direction on the substrate 300.

[0058] Illustrated in Figure 3C is yet another embodiment of a pattern of ink deposited on a substrate 300. This embodiment depicts lines drawn in a circular pattern 315 on the substrate 300. As with Figures 3 A and 3B, the lines of the pattern 315 can have a width within a range of 25 to 10 microns. The spacing between each line can be any distance. In some embodiments, the lines of the pattern 315 can be separated by a predetermined distance such that the resulting pattern causes the substrate 300 to be conductive and substantially transparent.

[0059] While the above describes Figures 3A-3C as patterns comprising lines, in some embodiments the patterns can comprise dots or areas of printed ink. In some embodiments the lines of the patterns can be a continuous line of connected dots, areas or geometries. In other embodiments, the lines of the patterns can be a non-continuous line of dots, areas or geometries. [0060] Illustrated in Figure 4A is one embodiment of a method for applying an ink to a substrate. The method can include applying an ink to the top of a plate (Step 405) and applying pressure to the top of the plate to cause the top of the plate to come into contact with the substrate 300 (Step 410). The plate is then pulled away from the substrate 300 after a predetermined period of time (Step 415) and the ink is permitted to cure (Step 420).

[0061] Further referring to Figure 4 A, and in more detail, in some embodiments ink is applied to the top of the plate (Step 405). The ink can be any ink described herein. In some embodiments, the ink can be a conductive nanoink comprising conductive, metallic nanoparticles. Any method can be used to apply the ink to the top of the plate. In some embodiments ink can be wiped, sprayed or otherwise deposited onto the plate.

[0062] The plate can be any plate 200 described herein. In some embodiments the plate 200 can be a plate 200 used in flexographic printing, letterpress printing or any hybrid printing technology that utilizes a plate 200.

[0063] Upon depositing the ink onto the plate 200, the plate 200 can then be applied to the substrate 300 so that the ink transfers from the plate 200 to the substrate 300 (Step 410). In some embodiments substantially all of the ink transfers from the plate 200 to the substrate 300. In other embodiments only a portion of the ink transfers from the plate 200 to the substrate 300. In these embodiments, the plate 200 retains a portion of the ink deposited onto the surface of the plate 200. Applying the plate 200 to the substrate 300 can include causing the plate 200 to come into contact with the substrate 300 and applying pressure to the plate 200. The application of pressure to the plate 200 causes the ink to adhere to the substrate 300 thereby causing the ink to be deposited onto the substrate 300.

[0064] The plate 200 can be in contact with the substrate 300 for any period of time. In some embodiments, this period of time can be any period of time needed to deposit a sufficient amount of ink onto the substrate 300. After this period of time elapses, the plate 200 can be pulled away from the substrate 300 (Step 415). Pulling the plate 200 away from the substrate 300 can include moving the plate 200 away from the substrate 300 or moving the substrate 300 away from the plate 200. In some embodiments, this step can include removing pressure from the top of the plate 200 so that the plate 200 and the substrate 30 no longer are in contact.

[0065] In some embodiments, the process of applying the plate 200 to the substrate 300 can result in the deposition of ink onto the substrate 300. Once the ink is deposited onto the substrate 300 the ink can be allowed to cure (Step 420). The time required to cure the ink can depend on the properties of the ink. In some embodiments, the time and temperature required to cure the ink can be any of the time and temperature combinations described herein.

[0066] Illustrated in Figure 4B is another method of depositing an ink onto a substrate 300. The method can include depositing the ink onto a substrate 300 in a pattern (Step 452) and permitting the ink to cure (Step 454). The ink can be deposited onto the substrate 452 using the method described in Figure 4A. In other embodiments, the ink can be deposited onto the substrate using any of the following printing processes: screen printing; gravure printing; letterpress; intaglio; offset lithography; offset lithographic printing; offset gravure printing; rotogravure printing; or flexographic printing, or any relief printing method. Still further embodiments can include depositing the ink using any hybrid print process comprising any of the print or ink deposition processes described herein. For example, one print process can include using a letterpress type of print plate on a flexographic print process.

[0067] When the ink is deposited onto the substrate 300, the ink can be deposited in any pattern described herein. In some embodiments, the ink can be deposited in any pattern. In other embodiments, the ink can be deposited in any pattern described in Figures 3A-3C. The ink can be deposited in a pattern such that the resulting substrate is both conductive and substantially transparent. The pattern, in some embodiments, can be designed to control the amount of ink deposited onto the substrate 300 and further control the print resolution.

[0068] In some embodiments, the ink can be deposited onto the substrate 300 in narrow conductive lines. In other embodiments, the ink can be deposited onto the substrate 300 in an ordered or random pattern. For example, the pattern can be an ordered pattern of dots or a random pattern of rings. The shape of the ink area and/or the pattern can be tailored to meet conductivity and transparency requirements. In some embodiments, the sheet resistance of the resulting substrate can be controlled by modifying the formulation of the ink (e.g. the rheological modifiers or binder) and the percentage of solids in the ink. By modifying these properties of the ink, the flow properties of the ink can be controlled.

Controlling this property of the ink can further allow one to control how much ink is deposited from the plate 200 or print medium to the substrate 300.

[0069] In another embodiment, disclosed is a method for manufacturing a

substantially transparent conductive structure, the method comprising: depositing a dispersion of metallic nanoparticles on a substrate in a pattern, wherein the pattern comprises lines having a width less than 50 microns; and curing the deposited dispersion to create a substantially transparent conductive structure, wherein greater than eighty percent of visual light transmits through the structure.

[0070] The method may further comprise depositing an adhesive on the substrate prior to depositing the dispersion. The adhesive may be a conductive adhesive.

[0071] In an embodiment, at least one of the metallic nanoparticles of the dispersion comprises any combination of silver, silver oxide and copper.

[0072] The pattern may comprise lines having a width less than 10 microns. A pattern comprising lines having a width of less than 5 microns is specifically mentioned.

[0073] In an embodiment, greater than ninety percent of visual light may transmit through the metallic structure. A metallic structure wherein greater than ninety- five percent of visual light transmits through the metallic structure is specifically mentioned.

[0074] The method may further comprise depositing a conductive coating onto the substantially transparent structure after curing the deposited dispersion. An embodiment wherein the conductive coating comprises an inorganic suspension of conductive components in an organic matrix is specifically mentioned.

Example 1

[0075] In one example, a transparent conductive substrate can be created by printing a conductive ink onto a substrate. The ink can be deposited using a letterpress plate in a flexographic print process. The plate can be any plate 200 described herein and can be configured to substantially reduce side printing. Ink can be deposited onto the substrate 300 using the plate 200. The ink can be deposited in an ordered pattern of ordered geometric areas to create a substrate that is conductive and substantially transparent.

Example 2

[0076] In one example, a transparent conductive substrate can be created by printing a conductive ink onto a substrate. The ink can be deposited using any print process that uses a plate such as any plate 200 described herein. The plate 200 can be configured to substantially reduce side printing. Ink can be deposited onto the substrate 300 in a random pattern of geometric areas such as bubbles or rings. The resulting substrate can be both conductive and substantially transparent. Example 3

[0077] In one example, a conductive structure that has no non-conductive areas can be formed by depositing a conductive ink onto a conductive substrate or conductive material (e.g. a conductive polymer.) The ink can be deposited using any of the print processes described herein and can be deposited in any pattern described herein. The resulting substrate can be a fully conductive substrate, (e.g. both the printed ink areas and the areas between the printed ink areas are conductive.)

Section C: Post Process Methods

[0078] In some embodiments, the processes described herein for depositing ink onto a substrate can include one or more post process methods. These methods can include post etching to improve line resolution and reduce line width.

Claims

1. A method for manufacturing a substantially transparent conductive structure, the method comprising:

depositing a dispersion of metallic nanoparticles on a substrate in a pattern, wherein the pattern comprises lines having a width less than 50 microns; and

curing the deposited dispersion to create a substantially transparent conductive structure, wherein greater than eighty percent of visual light transmits through the structure.

2. The method of claim 1 further comprising depositing an adhesive on the substrate prior to depositing the dispersion.

3. The method of claim 2 wherein the adhesive comprises a conductive adhesive.

4. The method of any of claims 1 to 3, wherein at least one of the metallic nanoparticles of the dispersion comprise any combination of silver, silver oxide and copper.

5. The method of any of claims 1 to 4, wherein the pattern comprises lines having a width less than 10 microns.

6. The method of any of claims 1 to 5, wherein the pattern comprises lines having a width less than 5 microns.

7. The method of any of claims 1 to 6, wherein greater than ninety percent of visual light transmits through the metallic structure.

8. The method of any of claims 1 to 7 wherein greater than ninety-five percent of visual light transmits through the metallic structure.

9. The method of any of claims 1 to 8, wherein the dispersion is deposited using any combination of flexographic printing, rotogravure printing, offset gravure printing, offset lithographic printing and intaglio printing.

10. The method of any of claims 1 to 9, further comprising depositing a conductive coating onto the substantially transparent structure after curing the deposited dispersion.

11. The method of claim 10 wherein the conductive coating comprises an inorganic suspension of conductive components in an organic matrix.