Patent Application
20150375246
A portion of the disclosure of this patent document contains material that is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the Patent and Trademark Office patent files or records, but otherwise reserves all copyright rights whatsoever.
The present disclosure relates generally to an article of manufacture and methods of producing the same, including in one exemplary variant a conductive element for use in, inter alia, mobile electronic devices such as cellular phones, smartphones, personal digital assistants (PDAs), laptops, and wireless electronic devices. In one exemplary aspect, the present disclosure relates to a conductive element (e.g., an antenna) formed using deposition of conductive fluids as well as the methods and equipment for forming the same in which the equipment utilizes more than one type of printing system.
Antennas and other conductive elements are commonly found in electronic devices, including most modern radio devices (such as mobile computers, mobile phones, tablet computers, smartphones, personal digital assistants (PDAs), or other personal communication devices (PCD)). Typically, antennas comprise a planar radiating plane and a ground plane parallel thereto, which are often connected to each other by a short-circuit conductor in order to achieve the matching of the antenna. The structure is configured so that it functions as a resonator at the desired operating frequency or frequencies. Typically, these internal antennas are located internal to the device (such as within the outer plastic housing), whether free-standing, disposed on a printed circuit board (PCB) of the radio device, or on another device component, so as to permit propagation of radio frequency waves to and from the antenna(s).
Aside from the high cost of manufacturing, such prior art antennas and approaches to antenna fabrication also generally consume appreciable space within the host device. As personal electronic devices such as smartphones and tablet computers continue to shrink, greater demands are place on the antenna utilized therein both from a performance perspective and a space consumption perspective. The latter is particularly acute, since the antenna must be able to operate effectively in the desired frequency band(s), yet consume the absolute minimum space possible. With largely planar antenna solutions such as those described above, a good deal of space may be wasted, since the antenna plane must be contained entirely within the housing, and often cannot be deformed or curved, such as to accommodate the curvature of a cellular telephone exterior housing. Such housings also have internal molded features or other components attached thereto, which cause further difficulty for one trying to adapt an antenna of a particular electromagnetic configuration to the housing while using only a minimum of interior volume.
As an attempt to address some of the foregoing issues, recent advances in manufacturing processes have enabled the construction of conductive elements such as antennas directly onto the surface of a specialized material (e.g., thermoplastic material that is doped with a metal additive). The doped metal additive is activated by means of a laser in a process known as laser direct structuring (LDS), which enables the construction of antennas onto more complex 3-dimensional geometries. In various typical smartphone and other applications, the underlying smartphone housing, and/or other components on which the antenna may be disposed inside the device, may be manufactured using this specialized material, such as for example using standard injection molding processes. A laser is then used to activate areas of the (thermoplastic) material that are to be subsequently plated. Typically an electroless copper bath followed by successive additive layers such as nickel or gold are then added to complete the construction of the antenna.
Although being very capable technology, LDS has also some disadvantages; specialized thermoplastics' material properties do not meet the properties of traditional polymer materials, but are typically more brittle or fragile. Another disadvantage is the total cost; specialized thermoplastics resins cost more than traditional ones, and lasering and plating processes are expensive. The capital cost of the LDS capacity also represents a significant barrier to entry into the technology.
One consequence of the high capital cost is a need to have dedicated LDS facilities for manufacturing articles having antennas. This may require that an antenna portion of a product be manufactured in one facility, with the product being integrated in another facility. This approach adds the cost of carrying and transporting an inventory of the antenna portions.
Accordingly, there is a salient need for an improved conductive element solution for e.g., the antenna(s) of a portable radio device, that offers comparable electrical performance to prior art approaches while being manufactured at lower cost and using more flexible, manufacturing processes. Certain implementations of such solution would also ideally provide enhanced economies of space, and complex geometric rendering capabilities, and moreover would reduce capital investment costs and reduce barriers to entry. Additionally, it is preferable to enable antenna manufacturing to be integrated with final product assembly.
Another requirement for antenna designs having large variations in metallic densities and minimum geometries over widely varying surface geometries create additional challenges. What is needed is a flexible manufacturing system and process that enables low cost and efficient manufacturing while addressing these needs.
In one aspect of the disclosure, a method of manufacturing is disclosed. In one embodiment, the method is for manufacturing an article of manufacture with a conductive trace pattern thereon, and the method includes: receiving information defining the conductive trace pattern; analyzing the information to define at least first and second domains; generating a first output relating to the first domain and a second output relating to the second domain; sending the first output to a first printing apparatus; and sending the second output to a second apparatus.
In one implementation, the method of manufacturing includes: receiving a file defining at least a portion of the conductive trace pattern to be formed upon a surface of an article of manufacture; analyzing the file to define at least two domains, including a first domain and a second domain, based at least in part upon a geometry of the surface; generating first and second print files corresponding to the first and second domains respectively; and sending the first and second print files to first and second printing systems respectively for use thereby.
In another implementation, the method includes: receiving a file defining at least a portion of the conductive trace pattern to be formed upon a surface of an article of manufacture; analyzing the file to define at least two domains, including a first domain and a second domain, based at least in part upon a trace geometry including one or more of trace width and trace thickness; generating first and second print files corresponding to the first and second domains respectively; and sending the first and second print files to first and second printing systems respectively for use thereby.
In a further implementation, the method includes: receiving a file defining at least part of the conductive trace pattern to be formed upon a surface of an article of manufacture; analyzing the file to define at least two domains, including a first domain and a second domain, the at least two domains having at least one boundary therebetween; generating first and second print files corresponding to the first and second domains respectively; extending traces in the first print file to overlap connecting traces of the second print file by a distance at least exceeding a misalignment tolerance between two printing systems; and sending the first and second print files to first and second printing systems respectively for use thereby.
In another implementation, the method includes: receiving a file defining at least part of the conductive trace pattern; analyzing the file to define at least two domains including a first domain and a second domain that are different based at least in part upon a geometric threshold, the at least two domains defining the entire conductive trace pattern and having a boundary therebetween; generating a first print file based upon the first domain and a second print file based upon the second domain; extending traces in the first print file to overlap connecting traces of the second print file by a distance at least exceeding a misalignment tolerance between two printing systems; and sending the first print file to a first printing system; and sending the second print file to a second printing system for use thereby.
In another aspect of the disclosure, an article of manufacture is disclosed. In one embodiment, the article comprises one or more conductive traces disposed on a substrate or other component so as to form an electrically operative element (such as e.g., an antenna). In one variant, the one or more traces include regions deposited using different deposition technologies.
In one implementation, the article of manufacture defines a surface having a conductive trace pattern formed thereon. The conductive trace pattern includes a plurality of domains including at least a first domain and a second domain. The plurality of domains collectively define the entire conductive trace pattern. The first and second domains have been formed utilizing different first and second printing technologies respectively, and have a boundary region therebetween. Traces from the first and second domains overlap in the boundary region to assure electrical continuity between traces of the first and second domains.
In another implementation, the article of manufacture defines a surface having a conductive trace pattern formed thereon. The conductive trace pattern includes a plurality of domains including at least a first domain and a second domain. The first domain is defined at least in part by relatively fine and/or thin traces formed primarily from conductive substantially spheroid particles having an average diameter that is between 1 and 100 nanometers. The second domain is defined at least in part by relatively wider and/or thicker traces formed primarily from conductive flakes having an average major dimension ranging from 2 to 20 microns.
In a further implementation, the article of manufacture defines a surface having a conductive trace pattern formed thereon. The conductive trace pattern includes a plurality of domains including at least a first domain and a second domain. The first domain is defined at least in part by traces deposited from a piezoelectric array of nozzles that each eject drops, such as those forming a dry volume in the range of 1 to 100 picoliters. The second domain is defined at least in part by traces deposited from a fluid dispensing nozzle that deposits drops, such as those forming a dry volume in the range of 500 to 10,000 picoliters.
In another implementation, the article of manufacture defines a surface having a conductive trace pattern formed thereon. The conductive trace pattern includes a plurality of domains including at least a first domain and a second domain. The first domain is defined at least in part by traces deposited based upon an aerosol stream that entrains drops, such as those each forming a dry volume that is less than 1 picoliter in volume. The second domain is defined at least in part by traces deposited from a fluid dispensing nozzle that deposits drops, such as those each forming a dry volume in the range of 500 to 5000 picoliters.
In yet a further implementation, the article of manufacture defines a surface having a conductive trace pattern formed thereon. The conductive trace pattern includes a plurality of domains including at least a first domain and a second domain. The first domain is defined at least in part by traces deposited from a piezoelectric array of nozzles that each eject drops, such as those each forming a dry volume in the range of 1 to 100 picoliters. The second domain is defined at least in part by traces deposited based upon an aerosol stream that entrains drops each forming a dry volume that is less than 1 picoliter in volume.
In another implementation, the article of manufacture defines a surface having a conductive trace pattern formed thereon. The conductive trace pattern includes a plurality of domains including at least a first domain, a second domain, and a third domain. The first domain is defined at least in part by traces deposited from a piezoelectric array of nozzles that each eject drops, such as those each forming a dry volume in the range of 1 to 100 picoliters. The second domain is defined at least in part by traces deposited based upon an aerosol stream that entrains drops, such as those each forming a dry volume that is less than 1 picoliter in volume. The third domain is defined at least in part by traces deposited from a fluid dispensing nozzle that deposits drops, such as those each forming a dry volume in the range of 500 to 5000 picoliters.
In still another implementation, the article of manufacture defines a surface having a conductive trace pattern formed thereon. The conductive trace pattern includes a plurality of domains including at least a first domain and a second domain. The first domain is defined at least in part by traces deposited from a piezo printhead operating in raster area fill print mode utilizing at least linear scans of the piezo printhead. The second domain is defined at least in part by traces deposited from a second printhead operating in a vector mode that moves non-linearly to define traces. The second printhead may be one or more of, e.g., a piezo printhead, an aerosol printhead, and/or a fluid dispensing printhead.
In a further implementation, the article of manufacture defines a surface having an insulative pattern and conductive trace pattern formed thereon. The insulative pattern separates portions of the conductive trace pattern to provide a capacitive structure. The conductive and insulative patterns are formed according to a method including: (1) using a first printhead to print a first portion of the conductive trace pattern, (2) using a second printhead to print the insulative pattern over a first area of the first portion of the conductive trace pattern, and (3) using a third printhead to print a second portion of the conductive trace pattern which partially overlays the insulative pattern and over a second area of the first portion of the conductive trace pattern. The first and third printheads can be the same printhead, or separate printheads.
In another implementation, the article of manufacture includes antenna traces (having an ability to resonate or radiate at least partly as a function of trace thickness), sensor traces (ability to detect capacitive changes), and/or connecting traces (ability to conduct versus insulate). The properties of the trace can determine what printhead has been selected during manufacture of the article.
In another aspect, a deposition apparatus is disclosed. In one embodiment, the apparatus includes at least two print apparatus, each configured to deposit at least part of a conductive trace or component on a substrate or surface. In one implementation, the two or more print apparatus are heterogeneous in technology; i.e., use different deposition technologies.
In one implementation, the deposition apparatus includes a first printing system and a second printing system for printing on a surface of an article of manufacture. The first printing system and second printing system are in data communication with one or more file processors. The file processor(s) receive(s) one or more input files defining a conductive trace pattern. The file processor generates a first print file and a second print file based upon the input file(s). The file processor sends the first print file to the first printing system, which then prints a first portion of the conductive trace pattern. The file processor sends the second print file to the second printing system, which then prints a second portion of the conductive trace pattern. The actions of the file processor can be fully automatic or can be based on human inputs to a user interface. Moreover, the operations of the first and second printing systems can be sequential (i.e., one after the other), overlapping but shifted in time, or completely concurrent, depending on the design and implementation of each.
In another implementation, the deposition apparatus includes a first printing system and a second printing system for printing on a surface of an article of manufacture. The first printing system is configured for printing at least fine traces, and includes a printhead generating smaller drops, such as those having a dry volume of less than 100 picoliters. The smaller drops contain spheroidal conductive particles, such as those having an average diameter of 1 to 100 nanometers. The second printing system is configured for printing antenna traces and includes a printhead generating larger drops, such as those having a dry volume of greater than 500 picoliters. The larger drops contain conductive flakes having e.g., an average major dimension of 2 to 20 microns.
In a further implementation, the deposition apparatus includes a first printing system and a second printing system for printing on a surface of an article of manufacture. The first printing system includes a piezoelectric printhead including an columnar arrangement or array of drop generators, at least a portion of which generate drops having e.g., an average drop volume in the range of 1 to 100 picoliters. The second printing system includes a fluid dispensing printhead generating drops having e.g., an average drop volume in the range of 500 to 5000 picoliters.
In yet another implementation, the deposition apparatus includes a first printing system and a second printing system for printing on a surface of an article of manufacture. The first printing system includes an aerosol-based printhead and can generate drops having an average drop volume of less than 1 picoliter. The second printing system includes a fluid dispensing printhead generating drops having an average drop volume in the range of 500 to 5000 picoliters.
In a further implementation, the deposition apparatus includes a first printing system and a second printing system for printing on a surface of an article of manufacture. The first printing system includes a piezoelectric printhead including an array of drop generators, at least a portion of which generating drops having an average drop volume in the range of e.g., 1 to 100 picoliters. The second printing system includes an aerosol-based printhead and can generate drops having an average drop volume of less than 1 picoliter.
In another implementation, the deposition apparatus includes a first printing system, a second printing system, and a third printing system for printing on a surface of an article of manufacture. The first printing system includes a piezoelectric printhead including an array of drop generators, at least some of which generating drops having an average drop volume in the range of e.g., 1 to 100 picoliters. The second printing system includes an aerosol-based printhead and can generate drops having an average drop volume of e.g., less than 1 picoliter. The third printing system includes a fluid dispensing printhead generating drops having an average drop volume in the range of e.g., 500 to 5000 picoliters.
In a further aspect, both methods and apparatus are disclosed which contemplate using a common output data structure (e.g., file) for two or more heterogeneous printing or other deposition processes, such as where for example a common data file contains data or information useful to each of the multiple different systems, or where the multiple systems are substantially contained within the same host system or apparatus.
In another aspect, a computer-readable storage apparatus is disclosed. In one embodiment, the apparatus comprises a medium having at least one computer program disposed thereon, the at least one program having a plurality of instructions which, when executed on a processing apparatus (such as a computer associated with the deposition apparatus referenced above), cause delineation of two or more domains within a prescribed conductive trace pattern (e.g., 3D trace file).
In one implementation, a computer-readable storage apparatus is disclosed. In one embodiment, the apparatus comprises a medium having at least one computer program disposed thereon, the at least one program having a plurality of instructions which, when executed on a processing apparatus (such as a computer associated with the deposition apparatus referenced above), causes at least the following process steps to occur: (1) an input data structure or structures (e.g., file or files) is/are obtained or accessed which defines a surface geometry of an article and at least part of an antenna trace pattern to be printed thereon, (2) the input file(s) is/are processed to define a plurality of print data structures (e.g., files), and (3) each of the plurality of print files are sent to one of a plurality of different printers (or print processes or functions within the same host system/apparatus), each of the different printers/processes/functions utilizing a different printing technology. In some particular embodiments, the steps can include an analysis to optimize a sequence of operation that determines factors such as which printers/processors/functions are utilized and when.
These and other aspects discussed further below will be readily appreciated by those of ordinary skill given the present disclosure.
All figures © Copyright 2014-2015 Pulse Finland Oy. All rights reserved.
The present disclosure concerns, in one aspect, an article of manufacture, including in one variant a conductive element (such as an antenna) formed onto a substrate. The conductive element includes a plurality of connected conductive traces. The traces may extend over a planar or non-planar or three dimensional substrate. According to the present disclosure the traces are formed in one exemplary embodiment using at least two different printing systems to form the conductive traces.
The article of manufacture 2 begins with a base substrate 4. In a first exemplary embodiment, the substrate 4 is composed of polycarbonate (PC). In a second exemplary embodiment substrate 4 is composed of polyamide (PA). Other embodiments may use other polymers such as PVC (polyvinyl chloride) or PET (polyethylene terephthalate). In some embodiments, the polymers can be filled with glass fibers, carbon fibers, glass beads, minerals, other filler types, and/or combinations thereof to name a few examples. Other possible materials for substrate 4 include metals, glass, and composites that combine different types of materials.
Each article of manufacture 2 includes the base substrate 4 and a conductive trace pattern 6 formed thereon. Various embodiments of the conductive trace pattern 6 can be planar or, as in the variant depicted in
Portions of the conductive trace pattern 6 may define a functional structure, such as e.g., an antenna 10. In one embodiment, portions of conductive trace pattern 6 that define the antenna 10 have a thickness that exceeds a multiple of a “skin depth” δ at a given operating frequency. Skin depth δ can be related to a formula describing how alternating current density varies with depth in a conductor which may be under the influence of an external alternating current field. A formula for current density is J=Jse−d/δ, where J equals a current density at a given depth d into the trace, and Js equals the current density at the surface of the trace. The value d equals a distance d measured from the outer surface of a conductive body along a direction that is perpendicular to the outer surface. A typical operating frequency is 1 GHz (gigahertz), although it will be appreciated that this value is merely exemplary (and in no way limiting of any operation parameter of the trace), and other values may be readily substituted. In some cases in which a material is a composite between conductors and insulators, we may refer to the skin depth as an “effective skin” depth that is based on material performance. The skin depth δ at a given frequency can be defined as the depth into the conductive body at which the current density J has fallen by about 63%, or to 1/e of the value at the surface. See, e.g., John R. Reitz, Frederick J. Milford, and Robert W. Christy, “FOUNDATIONS OF ELECTROMAGNETIC THEORY,” Third Edition, published in 1980 by Addison-Wesley Publishing Company, incorporated herein by reference in its entirety (see e.g., p. 369). The general formula for skin depth of a given material is δ=[2/ωμσ]1/2 wherein ω equals the angular frequency of the alternating current which may be imparted by incoming radiation, μ equals the magnetic permeability of the material, and σ equals the conductivity of the material. In the estimates that follow, the contribution of μ is ignored because it tends to be a constant for typical materials used, such as silver. For purposes of discussion the value of ω can be equal to 2π times the frequency of 1 GHz.
Each trace of the exemplary embodiment of the antenna 6 is formed from a conductive substance (e.g., fluid) that contains particles of a metal. Preferably, the metal has a high conductivity. Silver is one example of such a metal useful with this disclosure, although it will be appreciated that other metals may be used as well. Solid silver metal has a skin depth that is about 2 μm measured at 1 GHz. Traces formed from the conductive fluid will generally tend to have lower conductivity than that of bulk silver, at least partly because the particles tend to have low surface area contact with each other and are not perfectly compacted together.
For purposes of the present discussion, it is noted that a relationship can be defined between the skin depth of a printed trace formed from particles of a given metal versus the bulk metal itself. The formula is shown below in Eqn. (1):
δtrace=δbulk*σ1/2bulk/σ1/2trace Eqn. (1)
In the above relationship, δtrace is the skin depth of the trace, δbulk is the skin depth of the bulk metal, σ1/2bulk is the square root of the bulk conductivity, and σ1/2trace is the square root of the trace conductivity. This relationship states that the skin depth δ is inversely proportional to the square root of the conductivity.
Consider an example of silver particles used to make traces. Suppose that the conductivity of the bulk silver is 25 times that of the (particle-based) trace. The skin depth ratio in this example will be about 251/2 or about 5-tol. Since bulk silver has a skin depth of about 2 microns, the skin depth of the trace will therefore be on the order of 10 microns (five times that of the bulk material).
Note that the above comparison does not necessarily hold true for comparing traces versus bulk metal for different metals. For example, the formula is generally not accurate for comparison of bulk silver to traces formed from iron particles. This is because the two different metals have different magnetic permeability (μ) values which would then become a factor in comparing skin depths. The above ratios assume the same magnetic permeability, and that the magnetic permeability is not a dominating factor in comparing bulk metal properties to trace properties for a given metal.
According to
Referring back to
The conductive trace pattern 6 can also include wider traces 15 if desired. Wider traces 15, in one exemplary implementation, may have a width of at least 250 μm or at least 300 μm. The wider traces 15 can have a width of about 1000 μm in some cases. Generally speaking, in the present context, the term “wider traces” refers without limitation to the larger geometry features of conductive trace pattern 6 that have at least two orthogonal dimensions that exceed 250 μm.
An additive fabrication system according to the present disclosure is capable of efficiently forming conductive trace patterns 6 such as depicted in
Fabrication system 20 includes a file processor 22, first printing system 24, second printing system 26, and a drying and/or curing oven 28. Optionally system 20 may include another drying oven 29 between the first 24 and second 26 printing systems. File processor 22 is generally a computer configured to receive a file 23 that defines a conductive trace pattern 6 on a substrate 4 such as the conductive trace pattern 6 depicted in
In an exemplary embodiment the first printing system 24 is configured to print very fine traces 14 such as those depicted in
In another exemplary embodiment, the first printing system 24 includes a piezoelectric printhead such as piezo array printhead 140 discussed with respect to
Drying oven 29 may be deployed if desired/needed between first and second printing systems 24 and 26, such as to partially dry or cure conductive traces 6 before article 2 is printed upon by second printing system 26. This may not be necessary with the above-described exemplary embodiment, but may be preferable for other systems. In some cases the first printing operation is performed on a large batch of articles 2 that are stored between use of the first printing system 24 and second printing system 26. In such cases it may be desirable to cure or dry partially formed conductive traces 6 before temporary storage.
File processor 32 is configured to receive information or data, such as e.g., a file 33 that defines a conductive trace pattern 6 to be formed on substrate 4. File processor 32 is configured to process the input file 33 and output information (e.g., a print file 37) for each of printing systems 34-36 to be used in a given process.
In an exemplary embodiment of fabrication system 30 the first printing system 34 is a vector based printing system configured to print very fine traces 14. Such a printing system can include for instance a single-nozzle printhead 14 emitting a fine beam of aerosol. The first printing system is referred to as a vector-based system because the fine aerosol beam traces along the surface 8 to define the fine traces 14.
The second printing system 35 can be for example a raster-based printing system configured to print both fine traces 14 and wide traces 15. A typical raster-based printing system has a printhead with an array or columnar arrangement of nozzles that can define an area pattern of conductive traces 14 and/or 15. The exemplary columnar arrangement of nozzles can be, in one implementation, an inch or more in length and have 1000 or more nozzles. Such a columnar arrangement of nozzles can print a conductive pattern 6 very rapidly but has difficulty in printing into concave surfaces or recesses 12 or along compound surfaces 16. The second printing system in this exemplary configuration is referred to as a raster or pixel based system because it generates an area array of printed spots or pixels as opposed to being a vector device that defines a single trace at a time.
The third printing system 36 can be for example a vector-based for printing wide traces 15. Such a printing system can include a single-nozzle printhead that ejects relatively large droplets of conductive ink.
The above-described printing systems are examples for printing systems 34-36. The ordering of such printing systems 34-36 may change relative to the above example. Also, other printing systems may be utilized. For example, a vector-based printing system utilizing a single spray nozzle can be used to print the larger geometry traces and/or areas of metallization.
The exemplary embodiments of the fabrication systems 20 and 30 depicted above can be utilized to print a wide variety of different conductive trace patterns 6 on a wide range of substrate 4 surface geometries. To accommodate such varying designs, a number of different printing systems may be optimal in terms of their application. The following Table 1 illustrates a comparison of some exemplary printing systems.
The second row of Table 1 (just below the header row) summarizes an aerosol-based printing system operating in vector mode. An exemplary embodiment of an aerosol-based printing system is described with respect to
The third row of Table 1 summarizes an exemplary piezo-based printing system operating in raster mode. An exemplary embodiment of a piezo-based printing system is described with respect to
The fourth row of Table 1 above is the same as the third row except for the piezo head being operated in a vector mode. In this mode, the piezo printhead is optimized for generating very fine traces but not for area fills and large traces. Operating in this vector mode, an exemplary piezo printhead may be able to print widths in a range of 10 to 100 microns, and perhaps even finer than the aerosol head. Between raster and vector modes, a piezo printhead may be able to define any necessary trace width, provided the surface to be printed upon is sufficiently planar.
The fifth row of Table 1 summarizes an exemplary fluid dispense head-based printing system operating in vector mode. One implementation of a fluid dispense head-based printing system is described with respect to
A method of fabrication 40 that may apply to fabrication system 20 or 30 is depicted in
According to step 42 an input file 23 defining a conductive trace pattern 6 is received by file processor 22. The file 23 may be transferred to file processor 22 automatically, such as from a network connection or it may be manually inputted via a human operator using a computer user interface, or yet other approach.
According to step 44 the file is analyzed and domains or regions are defined. In one variant the domains are defined based upon one or more geometric factors such as the width of traces 14 or 15 and/or upon planarity or non-planarity of surface(s) 8. Collectively the domains define the entire conductive trace pattern 6. These domains or regions can relate to the capabilities of each of the printing systems 24 and 26. Yet other schemes for defining domains (which may or may not relate to area, position, geometry, relevant processes, etc.) may be used consistent with the present disclosure.
In one embodiment, at least two domains are defined according to the method of step 44 including a first domain and a second domain. The two domains are different based at least upon a geometric attribute or threshold. The at least two domains define the entire conductive trace pattern 6 and have a boundary therebetween.
According to step 46 an operational plan or sequence is optimized. One operational plan might be to just use one of printing systems 24 or 26. Another operational plan might be to use both printing systems 24 and 26 according to which system is more suitable for printing particular traces. According to step 46 the different operational plans are analyzed and then the one selected that best meets a certain criterion or multiple criteria, such as e.g., manufacturing cycle time (which varies roughly inversely with the number of articles 2 that can be manufactured per unit time). Also according to step 46 an optimal operational plan or sequence is selected.
According to step 48, the input file 23 is processed into at least two print files including a first print file based on the first domain and a second print file based on the second domain. According to step 50 the first print file is transferred to the first printing system 24 and the second print file is transferred to the second printing system 26.
According to step 52 the article of manufacture 2 is printed (e.g., sequentially) with printing systems 24 and 26. Within an exemplary embodiment of step 52 the following occurs: (1) An unprinted article of manufacture 2 is transported to printing system 24 (see block arrow at left). (2) First printing system 24 forms fine traces 14 upon surface 8. (3) Article of manufacture is then transported to printing system 26. (4) Second printing system 26 forms wide traces 15 upon surface 8.
According to step 54 the article of manufacture 2 is transported to drying (and/or curing) oven 28. Oven 28 then bakes article of manufacture 2, curing or driving away organic components of conductive trace pattern 6.
The printer controller 62 sends commands to robot controller 64 which in turn controls robots 68 and 70 to provide positioning and movement of article of manufacture 2 relative to printhead 66. Printer controller 62 sends commands to printhead 66 to eject aerosol, spray, and/or droplets of conductive ink onto article 2 while the printhead 66 is in proper proximity and orientation relative to surface 8 of article 2.
In a second embodiment, the robot controller continuously controls simultaneous synchronized cooperative motion of the rotation axis robot 70 and the multi-axis robot 68 to form conductive traces 6. This second embodiment has an advantage of potentially a shorter cycle time for dispensing the conductive trace(s) 6. A third embodiment is in effect a combination of the first embodiment and the second embodiment, whereby for some traces, the robots 70 and 68 move continuously in cooperation, and for some traces the robot 70 is halted while the robot 68 moves during a dispensing operation.
Referring to
Referring to
Referring to
In one implementation, the gas stream is focused to allow a considerable “throw distance” between exit orifice 98 and substrate 4, while still providing an ability to define very fine traces. The term “throw distance” generally refers in the present context to how far a printhead nozzle can be from a substrate during operation while still effectively forming traces on the substrate, without an unacceptable loss in quality. In one embodiment, the exit orifice 98 can be between 2 to 8 millimeters from surface 4 during trace formation. In another embodiment, the exit orifice 98 can be between 3 and 8 millimeters from surface 4 during trace formation. In yet another embodiment, the exit orifice 98 can be between 3 and 6 millimeters from surface 4 during trace formation. Having sufficient throw distance enables, inter alia, the printing system to print over highly irregular and curved surfaces, including into deep recesses.
In an exemplary embodiment, aerosol printhead 80 is part of a single-nozzle vector based system for “tracing out” the formation of fine conductive traces 14. This will be a premise behind an exemplary embodiment of printing system 24 of fabrication system 20. However, it is to be understand that an embodiment of aerosol printhead 80 can be comprised of a linear and/or staggered array of such nozzles 98, such that aerosol printhead 80 can form an area pattern of fine features. An array embodiment of aerosol printhead 80 could be used, for example, an “area fill” version of printing system 60.
The size of aerosol drops emitted by exit orifice 98 can be less than 1 picoliter (1 picoliter equals 10−12 liter) in drop volume. The size can be less than 100 femtoliters (1 femtoliter equals 10−15 liter), less than 10 femtoliters, or even less than 1 femtoliter. The directed aerosol beam 82 forms traces whose width is correlated more to the aerosol beam diameter than to the size of the individual aerosol drops.
The resultant dots or line widths that can be formed onto substrate 8 are advantageously very small. For example, individual dots can be, in the exemplary implementation, less than 25 microns, less than 20 microns, less than 15 microns, or even less than or equal to about 10 microns in diameter. This enables the formation of narrow conductive traces 14.
The fluid utilized in aerosol printhead 80 contains dispersed conductive nanoparticles. In an exemplary embodiment nanoparticles are approximately spherical or spheroidal in shape. They may be described as having an approximately round shape. Each particle has a diameter (or effective average diameter) D that is roughly equal to the diameter of a solid sphere having the same material and total weight of the nanoparticle which may have some shape irregularities. Generally speaking such nanoparticles have diameters less than 200 nm (nanometers).
In various embodiments the particles can have an average diameter D that is in the range of 1 to 100 nm, 1 to 25 nm, 1 to 10 nm to name some examples. In one such example, the average particle diameter D is about 60 nm. In another example, the average particle diameter D is within a range of 3 to 10 nm. In another embodiment, the average particle diameter D is in a range of 5 to 50 nm. In yet another example, the median particle size D is about 10 nm.
In an exemplary embodiment, most or nearly all of the solid content is provided by the conductive nanoparticles. By weight, the fluid can be 5 percent to 95 percent conductive nanoparticles. In some embodiments, the fluid can be 10 percent to 90 percent conductive nanoparticles by weight. In other embodiments, the fluid can be 20 weight percent to 80 weight percent conductive nanoparticles by weight. In yet other embodiments, the fluid can be 40 weight percent to 60 weight percent conductive nanoparticles by weight.
In another embodiment, the conductive fluid is about 50 weight percent silver nanoparticles. In this embodiment, the conductive fluid can be about 15 volume percent silver nanoparticles.
The balance of the conductive fluid is a vehicle that can include water and/or organic solvents or co-solvents. In some embodiments, the fluid vehicle includes a mixture of organic solvents. In some embodiments, the fluid vehicle includes an aliphatic hydrocarbon. In some embodiments, the fluid vehicle contains aromatic hydrocarbons. In yet other embodiments, the fluid vehicle can contain a mixture of an aliphatic hydrocarbon and an aromatic hydrocarbon. Some fluid vehicles can include for example one or more of xylene, hexane, toluene, and chloroform.
The conductive fluid viscosity can be for example in a range of 1 to 1000 cP (centipoise). Generally, a pneumatic nebulizer can be used as part of aerosol generation device 86 when the viscosity is in an adequate range (e.g., 20 to 1000 cP). For a pneumatic atomizer, preferably the viscosity is below about 200 cP. Nitrogen (N2) can be used as the atomizing gas. Conductive inks containing solvent vehicles having vapor pressures below about 1 mm Hg can be used. Examples of vehicle solvents can include xylene and ethylene glycol. For maintenance purposes, fluid vehicles that are water soluble can be useful. A pneumatic atomizer can produce aerosol droplets smaller than 1 micron in diameter.
An ultrasonic atomizer can be used as part of aerosol generation device 86, such as when the viscosity is in a range (e.g., of 1 to 20 cP). Some aerosol atomizers are effective with viscosities of about 5 cP or lower, and some are most effective with viscosities below about 3 cP. In one embodiment, the conductive fluid vehicle includes ethanol. An ultrasonic atomizer can produce aerosol droplets smaller than 0.2 micron.
Other operating parameters are possible consistent with the present disclosure and, for intermediate viscosities, either a pneumatic or an ultrasonic atomizer may be utilized depending upon the desired aerosol droplet size and other factors, as will be appreciated by those of ordinary skill. In some embodiments, the parameters utilized allow aerosol printhead 80 to output a focused beam 82 of droplets that are about three (3) microns in diameter.
An exemplary conductive ink suitable for use consistent with certain embodiments of the present disclosure has an average particle size of about 10 nm, a silver nanoparticle load of about 25 to 60 percent by weight, a hydrocarbon solvent, and a viscosity of about 1-30 cP (centipoise). This conductive ink would most likely be atomized with an ultrasonic atomizer.
Another exemplary conductive ink includes silver nanoparticles in a xylene solvent (aromatic hydrocarbon). The silver nanoparticle load is in the range of 25 to 40 weight percent. Due largely to the solvent used, the curing temperature used therewith can be 100 to 120 degrees Celsius.
Another exemplary conductive ink includes silver nanoparticles in a solvent mixture. The silver nanoparticle load is in the range of 25 to 40 weight percent. The curing temperature can be 120 degrees Celsius or higher.
In some embodiments, curing and/or drying the conductive inks (such as in the oven 28) is sufficient to remove the solvent vehicles. In other embodiments, the curing oven may result in a partial or complete sintering of the conductive nanoparticles. Sintering between the particles is often desirable, as it improves conductivity and thus reduces the skin depth. The occurrence of any sintering is a function of several factors, which can include material(s) used, the curing process, and cure temperature.
In various exemplary embodiments the nanoparticles are silver. However, other nanoparticles can be used, including for example aluminum, copper, or any other conductor usable for a given application. Moreover, the present disclosure contemplates mixtures of two or more heterogeneous substances. Silver has advantages of high electrical conductivity, and being relatively inert (including not generally being prone to thermal or other oxidation).
The use of a piezo pusher based “drop on demand” dispense head can have certain advantages. “Drop on demand” refers to an ability to programmably eject one droplet at a time at a range of desired drop ejection frequencies, drop sizes, and numbers of drops in a burst of drops.
In an exemplary embodiment, the nozzle opening 106 has a diameter DN in the range of 50 to 300 μm. In one implementation, the diameter DN is in a range of 70 to 200 μm. In yet another implementation, DN is in a range of 80 to 120 μm; e.g., about 100 μm. In an exemplary embodiment, the height h of the nozzle opening can be 0.5 mm to 5 mm (mm=millimeters or thousandths of a meter). In one particular exemplary implementation, h is about 3 mm.
As depicted in
The “throw distance” of the exemplary printhead embodiment (fluid dispense printhead 100) is generally less than that of aerosol printhead 80. In an exemplary embodiment, the nozzle 106 is positioned with a height H that is less than 2 mm above the substrate 4, but more than 0.2 mm. More particularly, in one implementation, H is less than 1 mm but more than about 0.2 mm. In another implementation, H is in the range of 0.4 mm to 1.0 mm. In another exemplary embodiment, H is about 1 mm.
When drops are ejected from the nozzle 106, there can be trajectory errors introduced due to drops that are ejected at some angle from the nozzle 106. Other sources of trajectory errors include airflow, and a translation velocity between the nozzle 106 and the substrate 4 parallel to the substrate 4. This translation velocity introduces a velocity component to ejected droplets of fluid that is not normal to the receiving surface of substrate 4. It is possible to compensate for this component through, e.g., drop ejection timing, but such compensation may introduce errors. One way to improve drop placement accuracy is to minimize H. But at the same time, a value of H that is too small may cause a “crash” between the nozzle tip 106 and the substrate 4 which could result in damage to the fluid dispense printhead 100 or to a resultant article of manufacture 2. Thus, it has been found by the inventors hereof that the discussed ranges for H are typically optimal for dispensing conductive fluid for conductive elements such as e.g., antennas, although other ranges may be used in the broader context of the present disclosure.
A control system within the exemplary implementation of the printing system 60 maintains the distance H to a consistent value while drops of conductive fluid are being dispensed upon the substrate 4. This is despite sometimes having to move the nozzle 106 over a three-dimensional surface 8 of a substrate 4. While moving along a straight or curved path, the nozzle 106 dispenses drops in a manner such that individual dots may be difficult to discern despite the use of large drops of conductive fluid. As defined in the present context, a stroke is the motion of a nozzle 106 relative to a substrate 4 during the formation of a trace portion of conductive pattern 6. The stroke can be linear or nonlinear in shape and/or rate of motion. A stroke can be executed over a non-planar path such that a plane cannot be fitted to the path of the stroke due to a non-planar substrate surface 8.
In an exemplary embodiment, the dispense or fluid dispense printhead 100 described above can form dots on a substrate having a dry volume of each dot (after solvent is dried) in the range of e.g., 1000 to 10000 picoliter (one picoliter is 10−12 liter). In a more particular embodiment, the dry volume of each dot is in the range of 2000 to 5000 picoliter. In one implementation, the dry volume of each dot is in the range of 2500 to 4500 picoliter. In yet another implementation, the dry volume of each dot is in the range of 3000 to 4000 picoliter, e.g., about 3500 picoliter. Having drop volumes within these ranges can enable the rapid production of exemplary antenna traces while avoiding drop-induced variations in trace impedance that might occur if the drops are too large.
In some embodiments, the fluid dispense head 100 can form dots on a substrate, each dot having a dry volume in the range of 500 to 5000 picoliter. In some embodiments, the fluid dispense head 100 can form dots on a substrate having a dry volume of each dot in the range of 1000 to 2000 picoliter. In yet other embodiments, the fluid dispense head 100 can form dots on a substrate having a dry volume of about 1600 picoliter.
In an exemplary embodiment, the dispense head 100 described above with respect to
The conductive fluid utilized with fluid dispense printhead 100 includes conductive particles in a fluid vehicle. The particle size and form factor are often important, with conductive flakes having a major dimension D less than about 20 μm preferable in certain implementations (although this number is in no way limiting).
The viscosity of the fluid can also be important in some applications. A more viscous fluid will tend to result in relatively stable drop formation and less flow of the traces after dispensing. However, lower viscosity can enable the use of smaller drops and higher drop ejection operating frequencies. The ranges of viscosities employed have been found to be advantageous and relatively optimal in rapidly forming conductive traces for e.g., antennas. In an exemplary embodiment, the viscosity of the conductive fluid is about 10 to 80 poise. In one implementation, the viscosity of the fluid is about 20 to 60 poise. In yet another implementation, the viscosity of the fluid is about 30 to 50 poise, or in the range of 35 to 45 poise. Viscosity according to these embodiments can be measured using e.g., a viscometer. Viscosities within these ranges have been measured using a cone and plate viscometer using a high shear cap at 50 RPM (revolutions per minute) at 25 degrees Celsius. The viscometer was a Wells-Brookfield Cone/Plate system provided by Brookfield Engineering Laboratories. Other approaches for viscosity determination may be used with equal success.
In some embodiments, the viscosity can be modulated according to a printhead temperature. If the printhead is heated, the viscosity may be reduced. In one embodiment, the viscosity of the conductive fluid is about 35 to 45 poise at 25 degree Celsius, but is about 15 to 20 Poise when heated to about 60 degrees Celsius in the printhead 34 just prior to drop ejection. Lowering viscosity can have the effect, inter alia, of increasing the ejected fluid drop velocity and drop volume for drops ejected from dispense printhead 100.
Additionally, polymers known to be mostly evaporated during the curing (e.g., oven drying) process are preferable to minimize insulative material between the conductive particles. Another component that can in some embodiments be beneficial is to include in the fluid vehicle is a component that will dissolve a thin surface of the substrate 4. This has the potential of yielding an improved bonding interface between the substrate 4 and conductive pattern 6. As an illustrative example, consider a conductive fluid used with a polycarbonate substrate 4. Certain aromatic hydrocarbons and ketones (such as MEK—methyl ethyl ketone) are known to dissolve polycarbonate. Certain other solvents from classes of esters, amines, and alcohols can also be utilized. Of course these are only illustrative and other components can be used depending upon the substrate material used. Including a fraction of such a component can improve adhesion between the conductive fluid and the substrate.
Using the fluid dispense printhead 100 described with respect to
Referring to
The selection of a trace width W is in the exemplary embodiment based upon such considerations as impedance, the presence or possibility of voids or other defects, and trace density. As the trace width decreases below a certain value (e.g., 0.3 mm in one particular case), an ability to form the trace based on a particular nozzle design can become increasingly challenging since a void in the trace (caused by, for example, and air bubble) of a given size is going to have a much greater impact on a narrower trace. A void may also provide an electrical constriction in the trace. Resistance at the constriction may be unacceptable. On the other hand, as the trace becomes wider, it may require more dispensing operations and trace geometry becomes constrained for higher density designs. Yet other factors or considerations may be important to the determination of optimal or desired trace width(s).
In one exemplary embodiment of the present disclosure, any or all of these thicknesses can be formed with a single stroke or pass of a dispensing head nozzle across a substrate surface, including composites of the foregoing (e.g., a first portion at thickness t1 and width W1, a second portion at thickness t2 and W2, and so forth, each of the portions in sequential order). In one embodiment, a single stroke of the dispensing head nozzle over the substrate 4 can form a trace 10 having a thickness t within a range of 30 to 50 μm. In one embodiment, a single stroke of the dispensing head nozzle over the substrate 4 can form a trace 10 having a thickness t within a range of 20 to 40 μm. In one embodiment, a single stroke of the dispensing head nozzle over the substrate 4 can form a trace 10 having a thickness t within a range of 30 to 50 μm or 25 to 35 μm or about 30 μm.
In some implementations it is preferable that the thickness t be at least a prescribed multiple (e.g., at least twice or at least three times) a skin depth δ for a given trace 10 to reduce or minimize an impedance to alternating current. In an exemplary embodiment, the trace 10 depicted in
In some implementations it is preferable that the thickness t be at least 4 or 5 times a skin depth δ for a given trace 10. In an exemplary embodiment, the trace 10 depicted in
In an exemplary embodiment, the particles 112 comprise silver particles. In other embodiments, the particles 112 can be formed from copper, aluminum, gold, or platinum, or any other high conductivity metal, or even alloys thereof. Moreover, the particles may be mixed with other (heterogeneous) particles, such as where silver particles and gold particles are mixed in a desired proportion (contrast, alloyed together).
In an exemplary embodiment, the particles 112 are substantially flattened, irregular-shaped particles such as “flakes”. Top and side views of an exemplary silver flake are depicted in
It will also be appreciated that one or more of the particle characteristics (such as e.g., C, A above) may be statistically distributed according to a function; e.g., a Gaussian or “normal” distribution, or other such function. For instance, most particles may fall within a given parametric range, with lesser portions of the whole falling within other ranges. In an exemplary embodiment, at least 95 percent by weight of the particles 112 have a dimension C that is less than 20 μm. In one particular implementation, at least 95 percent by weight of particles 112 have a dimension C that is less than 16 μm. It can be advantageous in certain cases to have a majority of particles (by weight) having a value of C that is e.g., larger than about 4 microns, larger than about 6 microns, larger than about 8 microns, or larger than about 10 microns. However, particles 112 having a major dimension C larger than about 20 μm can be difficult to dispense using the exemplary fluid dispense printhead 100. It is also noted that particles having a flake-like or plate-like or oblate (flattened sphere) form factor can provide advantages of a larger dimension C while being more amenable to nozzle dispensing. Hence, the present disclosure recognizes that particle shape, among other things, can be a significant determinant of performance, and in fact can be controlled to achieve one or more desired properties or characteristics such as e.g., reduced nozzle clogging, enhanced flow, better pattern consistency, etc.
In an exemplary embodiment, the minor dimension A (thickness of particle 112) is in the range of 0.3 to 4.0 μm for the majority of particles by weight. In another implementation, A is in the range of 0.5 to 2.0 μm for the majority of particles by weight. In yet another implementation, A is in the range of 0.5 to 1.0 micron, or even in the range of 1.0 to 2.0 micron for the majority of particles by weight. For instance, one particular embodiment uses particles having A on the order of 0.6 micron for the majority of particles by weight.
The form factor of particles 112 can be defined by any number of metrics, such as the ratio of C (the major dimension) to A (the minor dimension or thickness). In an exemplary embodiment, the ratio of C to A is more than 2 for the majority of the particles by weight. In another implementation, the ratio of C to A is more than 4 for the majority of the particles by weight. In yet another implementation, the ratio of C to A is more than 8 for the majority of the particles by weight.
It has been observed that in certain cases, when the conductive trace portion 110 is dispensed and cured, a fraction of particles 112 often tend to align themselves along an outside surface 116 of the trace portion 110, whereby the major axis C of a particle 12 is in general alignment with the outside surface 116. Of course there is some degree of random orientation, but it has been noted by the inventors hereof that such alignment tends to occur particularly for particles 112 having a longer major axis C, such as those having a value of C that is 4 microns or more. Also the particles 112 disposed away from the outside surface 116 appear to tend to have more of a random orientation.
Other bonding chemical and/or mechanical mechanisms at the interface 118 can be possible. For example, the bonding mechanism at interface may include any or all of polar, van der Waals, ionic, and/or covalent bonding. The fluid used to form trace portion 110 may includes an adhesion promoter which forms a coupling agent between trace 110 and substrate 4.
According to step 120 an input file 23 is received by file processor 22. According to step 122 the file is analyzed and all traces having a width W less than a certain threshold are identified. In an exemplary embodiment this width W is 300 μm. For purposes of illustration it is assumed that some of the traces have a width above this threshold and some have a width below the threshold.
Also according to step 122 at least two domains are defined including a first domain having traces whose width W is below the threshold and a second domain having traces whose width W is above the threshold. At least two domains collectively contain the entire conductive trace pattern 6 to be printed.
According to step 124, two process times are computed: (1) the process time required to print the entire trace pattern using the aerosol printhead 80 and (2) the process time required to use aerosol printhead 80 to print all traces below 300 μm in width and to use fluid dispense printhead 100 to print all traces having a width of 300 μm and above. According to step 126 a decision is made based upon comparison of process times. If using fluid dispense printhead 100 does not reduce the process time then a single aerosol print file is generated according to step 128 and the entire trace pattern 6 is printed using aerosol printhead 80 according to step 130.
For most situations requiring small traces 14, however, the process time will be reduced by using both printheads 80 and 100. This is particularly true because many conductive patterns 6 will only have a relatively small percentage—sometimes less than 5 or 10 percent—of the total area of conductive traces below the width threshold for system 100.
According to step 132, two overlapping files including a first file and a second file are created based upon the first and second domains respectively. The files are overlapped to provide a suitable contact area between nanoparticle traces from aerosol printhead 80 and silver flake traces from fluid dispense printhead 100. The overlap is defined to exceed a combined misalignment tolerance between aerosol printhead 80 and fluid dispense printhead 100. The first file defines the narrower geometry traces 14. The second file defines the wider geometry files 15. In an exemplary embodiment the narrower geometry traces 14 are extended into the wider traces 15 in order to define the overlap. In another exemplary embodiment the wider geometry traces 15 are extended into the narrower traces 14 in order to define the overlap. Also according to step 132, the first file is transferred to first printing system 24, and the second file is transferred to the second printing system 26.
According to step 134, the first printing system 24 prints the fine geometry traces 14 using the aerosol based aerosol printhead 80. According to step 136, the second printing system 26 prints the larger geometry traces 15 using the fluid dispense printhead 100.
Aspects of trace 14 have been discussed with respect to
In an alternative embodiment, the fine geometry trace 14 is formed with a piezo array printhead 140 (to be discussed with respect to
In one embodiment, each of the columnar arrangements 146 is at least 0.5 inches in extent, and includes at least 100 nozzles. In another embodiment, each of the columnar arrangements is about one inch in extent and includes at least 300 nozzles. Other embodiments can include 600, 1200, or even 2400 nozzles. Yet other numbers and/or configurations of nozzles may be used consistent with the present disclosure.
Each nozzle is configured to eject a conductive ink containing conductive nanoparticles similar to those ejected by aerosol printhead 80. In one embodiment, the nanoparticles have diameters of less than 100 nm (nanometers). An exemplary ink can have nanoparticles with a diameter between 3 to 10 nm, a solid content of about 45 percent, a viscosity of about 4 to 5 cP (centipoise), with an organic fluid vehicle. This is but one example, and it will be recognized that the particle size and fluid properties can vary greatly. In an exemplary embodiment, the nanoparticles are silver nanoparticles, although others may be used (including heterogeneous mixes) as previously described.
In an exemplary embodiment, each nozzle 148 is configured to eject droplets having a fluid volume in the range of 0.2 to 200 pL (picoliter). In a more particular embodiment, the fluid drops are in the range of 1 to 100 pL (picoliter). In another particular embodiment, the fluid drops are in a volume range of 1 to 30 pL (picoliter).
The printing system 35 is configured to move the nozzle face over substrate 4 in a direction that is perpendicular to a long axis of the columnar arrangement 146. As the nozzle face is moved, the nozzles 148 are actuated to form a dot matrix arrangement of conductive ink drops over substrate 4 to define a portion of conductive trace pattern 6. This type of printing system is referred to as a “raster” printing system, and is very efficient at defining high density and high area coverage arrangements of conductive traces. Vector printing systems such as those utilizing aerosol printhead 80 or fluid dispense printhead 100 tend to be less efficient and more time consuming in forming such a high density conductive trace arrangement.
However, despite the efficiency advantages of raster printing, there may be reasons to operate piezo array printhead 140 in a vector mode, whereby one or more nozzles 148 trace out a portion of a conductive trace pattern 6 in a manner similar to that of fluid dispense printhead 100. An advantage of the vector mode is that much finer traces are enabled with a given nozzle 148.
The effective “throw distance” of a piezo array printhead 140 is dependent upon at least drop size. For smaller drops, the distance between nozzle face 142 and substrate 4 may need to be less than 2 millimeters. Preferably the distance is in the range of 0.5 to 1.5 millimeter or from 0.8 to 1.2 millimeter. If the surface 8 to be printed upon is highly irregular, this may be difficult due the physical extent of nozzle face 142.
One or all of printing systems 34-36 can be utilized for a given conductive trace pattern 6. According to this exemplary embodiment systems 34, 35, and 36 utilize printheads 80, 100, and 140 respectively. To understand why more than one printhead 80, 100, and/or 140 would be used, it is useful to describe the conductive trace pattern 6 in terms of domains which are in one embodiment defined as portions of conductive trace pattern 6 each having particular geometric attributes of the traces 6 and/or the surface 8. Table 2 below defines some of these domains.
Domain number (type) I includes wide traces 15 having a width above a predetermined threshold. In an exemplary embodiment, this threshold is 300 μm. The geometry of surface 8 within domain type I is “proud”—meaning that it is not recessed or concave. More specifically the surface 8 does not have points that are recessed relative to surrounding points beyond a certain threshold. In an exemplary embodiment, “proud” means that points are not recessed more than a given value; e.g., 0.5 millimeters relative to surrounding points. “SA CURVE” (single axis curvature) indicates that domain type I does not have two axes of curvature that result in a height difference exceeding a threshold along two axes within the domain. In an exemplary embodiment, the threshold would be about 0.5 millimeter. As indicated above, domain I can be printed upon by all three printheads including aerosol printhead 80, piezo array printhead 140, and fluid dispense printhead 100. However, because the metal density is high, the piezo array printhead 140 can probably print domain I most efficiently. Note that a high metal density can refer to a very high density of narrower traces, or it can refer to a very wide trace that is a multiple of the width that can be printed by fluid dispense printhead 100 requiring a number of strokes to achieve the width, or yet other definitions.
Domain type II is the same as domain type I, except that the trace density is low. While all three printhead types (80, 100, 140) can print domain type II, it may be most efficient to print domain type II with fluid dispense printhead 100.
Domain type III has a surface geometry that is either recessed or has double axis curvature. In an exemplary embodiment, the term “recessed” refers to the surface having points that are recessed more than a certain predetermined threshold relative to surrounding points. In one implementation, this threshold is 0.5 millimeters. In an exemplary embodiment, the term “double axis curvature” means that the surface is “crowned” or peaked, and that the surface falls away by a distance exceeding a threshold, such as e.g., 0.5 millimeters along two approximately orthogonal axes. With domain type III, the piezo array printhead may not be able to effectively print the traces because the increased distance between printhead nozzles and the print surface 8 may cause unacceptable printing errors. Therefore, vector dispense printheads 80 or 100 (or other comparable performance techniques) may be needed to print domain type III. Because the traces are comparatively wide, the fluid dispense printhead 100 can generally print domain type III most efficiently.
Domain type IV is the same as domain type I, except having narrow traces 14. Narrow trace width is defined as having traces below some threshold, such as below 300 μm. Either aerosol printhead 80 or piezo array printhead 140 can print domain IV. However, the piezo array printhead 140 can probably print domain type IV most efficiently due to the high trace density (provided that piezo array printhead 140 has a sufficiently high resolution).
Domain type V is the same as domain type II, except having narrow traces 14. Domain type V is also the same as domain type IV, except having a low trace density. Either aerosol printhead 80 or piezo array printhead 140 can print domain IV. However, aerosol printhead 80 may be able to print domain type V most efficiently, due to the low trace density.
Domain type VI is the same as domain type III, except for having narrow traces 14. As a result, aerosol printhead 80 may be the only viable candidate for printing domain type VI.
Table 3 below lists a number of exemplary printing sequences that can be utilized to form the conductive trace pattern 6. The numbers 1, 2, and 3 indicate the order in which a given printing system is used. For example, sequence B utilizes the aerosol printhead 80 first (indicated by 1 as first in the sequence) and then the piezo array printhead 140 second (indicated by 2 as second in the sequence). However, sequence B does not utilize the fluid dispense printhead 100. Using sequence B all of the domains can be printed. But this may not be the most efficient sequence for some conductive trace patterns 6. While table 3 depicts a certain ordering of printhead use other orders are possible such as one starting with the piezo array printhead 140 or any other ordering utilizing the various printheads described. Therefore other sequences other than those listed in table 3 are possible.
Sequence A only utilizes aerosol printhead 80 to print the entire conductive trace pattern 6. This sequence A can be used to print all six domain types. This sequence may be effective if the conductive trace pattern 6 only includes a small total length of fine traces 15. However, if the conductive trace pattern has a large number of wide traces and/or a large and high trace density, sequence A can have an unacceptably long cycle time.
Sequence B includes the use of the aerosol printhead 80 followed by the piezo array printhead 140. Like sequence A, this sequence can also print all six domain types.
Sequence C includes the use of all three printheads in sequence including aerosol printhead 80 followed by piezo array printhead 140, and finally the fluid dispense printhead 100. Sequence C can print all fix domain types.
Sequence D only utilizes piezo array printhead 140 to print the entire conductive trace pattern 6. Sequence D can be utilized to print domain types I, II, IV, and V. This is typically the most efficient sequence for printing a conductive trace pattern 6 that is planar to within a predetermined threshold such as 0.5 mm. However, sequence D will generally not be effective if the surface to be printed has recessed or compound bend geometries meeting the criteria of domains III or VI.
Sequence E utilizes the piezo array printhead 140 followed by the fluid dispense printhead 100. Sequence E is effective for printing all domain types except for domain type VI, since type VI requires fine traces 14 that are on a surface geometry not addressable by piezo array printhead 140.
Sequence F only utilizes fluid dispense printhead 100. Sequence F can be utilized if the entire conductive trace pattern is formed from wide traces 15.
Referring again to
According to step 150, one or more file(s) 33 defining a conductive trace pattern 6 are received by file processor 32. According to step 152, the file processor 32 analyzes the file(s) and then divides the conductive trace pattern up, such as e.g., into domains such as the domains I-VI discussed with respect to Table 2. The domains can be, in one implementation, separated by boundaries along surface 8, or they can be separated according to portions of the conductive trace pattern 6. The domains collectively define the entire conductive trace pattern 6. In an exemplary embodiment, the domains are divided up according to trace width, surface geometry, metallic coverage density (otherwise referred to as trace density), and trace thickness.
According to step 154, candidate print sequences are identified. Candidate print sequences are determined based upon the types of domains identified (which may preclude certain sequences, as is apparent from Table 3).
According to step 156, one or more metrics such as process cycle time are evaluated for the alternative print sequences. According to step 158, an optimal print sequence is selected based upon the metric evaluated. Step 158 includes in one embodiment a mapping of each of the identified domains to one of printing systems 34 (aerosol), 35 (piezo array), or 36 (fluid nozzle). It will be appreciated, however, that the present disclosure further contemplates the instance where a given domain is mapped to two or more of the printing systems 34, such as where a domain may be constructed as a “composite”; e.g., using these two or more systems due to e.g., different features or requirements occurring within that domain.
There are boundaries between various domains into which the conductive trace pattern 6 is divided (see
According to step 162, portions of the input file 23 defined by the domains and including any trace extensions are converted into print files each specific to the printer mapped to the domain. According to step, 164 any domains mapped to aerosol printing system 34 are printed. According to step 166, any domains mapped to piezo array printing system 35 are printed. According to step 168, any domains mapped to fluid nozzle printing system 36 are printed. According to step 170, the article 2 is baked in oven 38 to cure and/or dry the conductive trace pattern 6.
Once the optimal sequence is selected the traces need to be extended between domain boundaries (step 160 of
The traces in domain III are also extended into domain II. One primary reason is that fluid dispense printhead 100 can better print on a planar surface than the piezo array printhead 140 can print into a recess. Also, the fluid dispense pattern formed by piezo array printhead 100 is thicker. The trace extension assures proper electrical coupling between traces printed by the two printing systems, despite printhead-to-printhead alignment tolerances.
There are no traces extensions across boundaries between illustrated domains I and IV, I and II, or II and V, because they are all printed by the same piezo array printhead 140. This is one advantage of minimizing the number of printing systems to print the different domains, and can be part of the optimization performed (steps 156 and 158).
Once the traces have been extended, the print files for the printing systems are determined. The resultant print sequence is as follows: (1) the aerosol printhead 80 prints domain VI including traces extending into domain IV; (2) the piezo array printhead 140 prints domains I, II, IV, and V; and (3) the fluid dispense printhead 100 prints domain III extending the traces into domain II. The article of manufacture is then cured (e.g., baked, exposed to electromagnetic or other radiation, or other means).
Consider the conductive trace pattern 6 illustrated in
One or both of printing systems 24 and 26 may be used for a given trace pattern 6 depending upon the geometry of surface 8. Table 4 below describes the trace pattern in terms of domains that may be useful in determining a capable and optimum set of print operations.
Domain type I has a surface 8 that is similar to that described with respect to domain type I of Table 2. The surface is not recessed or crowned (having a high point rising above surrounding points in along two axes) beyond a certain height difference threshold, such as e.g., 0.5 millimeters. For domain type I, the metal trace density is above a certain metal trace density threshold that tends to render printing system 24 inefficient.
Domain type II is similar to domain type I except that the metal trace density is below the metal trace density threshold. While both printing systems 24 and 26 can print domain type II, it may be more efficient to print domain type II with printing system 24.
Domain type III has a surface 8 that is either recessed or crowned along two directions beyond a height different threshold such as 0.5 millimeters. This surface may require the use of printing system 24, since use of printing system 26 may result in a degradation in the quality of the metal traces being printed.
Table 5 lists a number of possible printing sequences that can be utilized to form the conductive trace pattern 6. The numbers 1 and 2 indicate the order in which a given printing system is utilized.
Sequence A only utilizes aerosol printhead 80 to print the entire conductive trace pattern 6. This sequence may be necessary for example if all traces to be printed are in a recess, or on a crowned surface for which the piezo array would suffer degraded printed quality. This sequence may also be efficient for printing a small number of fine traces.
Sequence B includes the use of aerosol printhead 80 followed by piezo array printhead 140. This sequence can print all domain types effectively.
Sequence C only utilizes the piezo array printhead 140. This can be effective for example if the surface 8 is close to flat or has only one significant radius of curvature that is convex.
Referring to
According to step 172, one or more file(s) 23 defining a conductive trace pattern 6 are received by file processor 22. According to step 174, the file processor 22 analyzes the file(s) and then divides the conductive trace pattern up into domains such as domains I-III discussed with respect to Table 4. The domains can be e.g., separated by boundaries along surface 8, or they can be separated according to portions of the conductive trace pattern 6, or yet according to other schemes. The domains collectively define the entire conductive trace pattern 6. In an exemplary embodiment, the domains are divided up according to surface geometry and metallic trace coverage density.
According to step 176, candidate print sequences are identified based on the domains identified in step 174. According to step 178, process metrics such as cycle time are evaluated for the alternative process sequences. According to step 180, an optimal sequence is selected. Step 180 includes mapping each domain to a printing system 24 or 26.
There may be boundaries between domains that are printed with different printing systems across each boundary. Along such boundaries, the traces are extended so that they overlap according to step 182. They may be extended for both printing systems or just extended for one of the printing systems. According to step 184 portions of the input file 23 including any trace extensions from step 182 are transformed into print files each specific to the printer mapped to the domain.
According to steps 186 and 188, the selected print sequence is executed. According to step 190, the article of manufacture is cured (e.g., baked) to remove solvent vehicles from conductive ink.
Consider the conductive trace pattern 6 illustrated in
The methods described for
Domain type I is an inner portion of a wide feature, such as a wide trace. This is most efficiently printed using piezo array printhead 140 in raster print mode.
Domain type II is a perimeter portion of a wide feature. This can be printed using either piezo array printhead 140 in vector mode, or using aerosol printhead 80.
Domain type III is a narrow trace array. This can be printed using either piezo array printhead 140 in vector mode, or using aerosol printhead 80.
Domain type IV is an array of traces inside of a recess (or crowned feature) that precludes the use of piezo array printhead 140. For such an area, the aerosol printhead 80 is optimal.
A print sequence for forming the conductive trace pattern 6 of
An alternative embodiment for forming domains I and II of
Table 7 (below) describes a trace pattern 6 in terms of exemplary types of domains. This design has particular requirements for a printing system. Exemplary domain I is flat or nearly flat to within 0.5 mm. The metal in domain I is a solid area fill of metal. The selected printing system for domain I will include piezo array printhead 140 operating in a raster (area fill) print mode.
Exemplary domain II is flat or nearly flat to within 0.5 mm like domain I. However, domain II has an arrangement of very fine traces. The selected printing system for domain II will include piezo array printhead 140 operating in vector mode to enable the definition of very fine traces.
Exemplary domain III is highly curved and not amenable to piezo array printhead 140. The traces are mostly antenna traces and, as such, are relatively wide and thick to provide an appropriate skin depth multiple. The selected printing system for domain III is fluid dispense printhead 100 operating in vector mode.
Referring again to
According to step 204, an analysis and print sequence optimization may be performed. For illustrative purposes, a particular printing sequence is described.
According to step 206, traces are extended to provide overlap. In one embodiment, the wider traces of domain III are extended slightly to overlap traces of adjacent domains. The magnitude of the extension is equal at least to a misalignment tolerance between printing systems.
According to step 208, defined traces for each domain are converted into appropriate data structures (e.g., print files). According to step 208, the traces of domain I are converted in to raster print files for the printing system 24 utilizing piezo array printhead 140. Also according to step 208, the traces of domain type II are converted into vector print files for the printing system 24 utilizing piezo array printhead 140. Yet also according to step 208, the traces of domain type III are converted into vector print files for the printing system 26 utilizing fluid dispense printhead 100. Traces for domain type III have been extended such that the print files for the printing system 26 will extending into and overlap print files defined for printing system 24.
According to step 210, the printing system 24 executes the print file defined from domain I, and thereby forms metallic area fill patterns by operating piezo array printhead 140 in raster area fill mode. According to step 212 the printing system 24 executes the print file from domain II and thereby forms fine traces by operating piezo array printhead 140 in vector mode.
If there is a delay between using the first printing system 24 and second printing system 26, the article of manufacture 2 can be baked according to step 214. According to step 216, the printing system 26 executes the print file defined from domain III and therefore forms wide antenna traces by operating fluid dispense head 100 in vector mode. As a note, the wide antenna traces overlap metallization of domains I and/or II. According to step 218, the article of manufacture is baked.
Domain II of the conductive trace pattern 306 includes fine traces 314. The fine traces 314 are printed using the piezo array printhead 140 operating in a vector print mode mode. The fine traces 314 define electrical connections to a chip mounting location 317.
Domain III of the conductive trace pattern include wide traces 315. The wide traces 315 are printed using fluid dispense printhead 100 operating in a vector print mode.
The printing system 500 includes a transport belt 502 that imparts motion to the articles 504 as depicted from left to right in
The exemplary printing system 500 includes one or more loading zones 506 upon which articles 504 are loaded. Once loaded, the articles 504 are transported via the belt 502. The printing system 500 includes one or more cameras and/or sensors 508 which is/are utilized by the printing system 500 to align the articles 504 relative to other portions of printing system 500, including the printheads 510. In one embodiment, the printheads 510 are piezo printheads similar to piezo array printhead 140 described with respect to
The printing system 500 optionally includes an IR lamp 512 or other curing source/agent/process to partially cure or dry ink ejected from a printhead 510 before an article passes (shown as left to right) to a second printhead 510. The printing system 500 also may includes a cure lamp 514 for more completely drying ink ejected from printheads 510 after printing is complete. The printing system includes a controller 516 that is coupled to the cameras/sensors 508, printheads 510, and optionally a device (not shown) that provides information concerning the speed of belt 502 or other conveyance mechanism.
An exemplary embodiment of a printing operation for a given article 504 (which may include a pallet or other such component) includes the following: (1) The article 504 is loaded onto the belt 502 at the loading zone 506. The belt 502 then begins transporting article along a direction belt motion direction. (2) The article 504 passes under the camera 508. The camera 508 captures an image of the article 504 that is very rapidly timestamped by the controller 514. The controller 514 utilizes the image, timestamp, and a sensed or input belt speed (of the belt 502) to synchronize the printheads 510. (3) The article 504 passes under the printhead 510 that then prints a conductive trace pattern onto the article 504.
While the printing system 500 has been described with respect to a belt 502, other options are possible. For example, an alternative printing system may utilize a chain of pallets into which individual articles 504 are loaded. This would have the advantage of enabling a more precise location of articles 504 but would tend to be a more costly system. Also, pick-and-place and/or other types of conveyances may be used consistent with the disclosure.
In some embodiments of the disclosure, it may be desirable to form non-conductive features such as semiconductors and/or insulators. The semiconductors and/or insulators would form a portion of article 2, and can be electrically coupled to conductive trace pattern 6. Any or all of the systems, printheads, or methods discussed above can be applicable to printing such semiconductors and/or insulators. The print fluids utilized can include without limitations any or all of conductors, semiconductors, dielectrics, and/or insulators whether of an organic and/or inorganic nature. The print fluids can take the form of liquid solutions, dispersion, and/or suspension. The print fluids can include other materials such as conductive polymers, conductive oxides (e.g., indium tin oxide), carbon nanotubes, or graphene, to name a few examples.
Printing systems that can be used as one of the printing systems described with respect to
The present disclosure also provides an example of mass customization. Mass customization is a new and expanding frontier in manufacturing industries. Shorter runs driven by mass customization, and resultant smaller lot sizes, for e.g., traditional wire-wound inductive devices (such as e.g., inductive reactors/choke coils, transformers, etc.) heretofore has required extensive setup and overhead costs (e.g. adjusting flyers, shields, guiding elements etc.). It is arguably not possible to face tomorrow's market requirements (such as small lot sizes or high product flexibility) with current manufacturing approaches. The new approaches described herein for trace deposition, such as for an improved inductive device, allows for accurate wire placement, wire width, and wire gaps by using, for example, generalized printing techniques. These can be digitally constructed with each layout being unique, down to even a single manufacturing unit. For example, the use of flexible computer-aided printing systems in manufacturing can be used to produce custom layouts item-by-item. These systems have advantages when combined with low costs from mass-produced planar windings with the flexibility of individual customization. Consequently, the number of manufacturing steps can be reduced, and flexibility around a given job design specification can be realized. A benefit of this innovation is a tremendous increase in variety and customization without a corresponding increase in costs that would be incurred under available prior art approaches.
The present disclosure advantageously may be used to replace various processes that were heretofore inflexible and capital intensive, such as laser direct sintering (LDS) for the purposes of fabricating antennas or other components. In replacing LDS, the present disclosure has a number of advantages, including without limitation (1) compression of supply (consolidation of steps), (2) reduced cycle time for development and production (consolidation to the point of production), (3) flexible manufacturing (“on the fly” design changes), (4) faster response to manufacturing demand changes, (5) less environmental impact relative to electroplating, (6) less inventory requirements (since LDS requires building up an inventory at one site before shipment to another site), and/or (7) improved working capital.
While being described relative to antennas, the present disclosure applies to other electrical components as well such as a sensor coil. More generally as used herein, the terms “electrical component” and “electronic component” are used interchangeably and can refer to components adapted to provide some electrical and/or signal conditioning function, including without limitation inductive reactors (“choke coils”), transformers, filters, transistors, gapped core toroids, inductors (coupled or otherwise), capacitors, resistors, operational amplifiers, and diodes, whether discrete components or integrated circuits, whether alone or in combination.
It will be appreciated that while certain steps and aspects of the various methods and apparatus described herein may be performed by a human being, the disclosed aspects and individual methods and apparatus are generally computerized/computer-implemented. Computerized apparatus and methods are necessary to fully implement these aspects for any number of reasons including, without limitation, commercial viability, practicality, and even feasibility (i.e., certain steps/processes simply cannot be performed by a human being in any viable fashion).
It will be recognized that while certain aspects of the disclosure are described in terms of a specific sequence of steps of a method, these descriptions are only illustrative of the broader methods of the disclosure, and may be modified as required by the particular application. Certain steps may be rendered unnecessary or optional under certain circumstances. Additionally, certain steps or functionality may be added to the disclosed embodiments, or the order of performance of two or more steps permuted. All such variations are considered to be encompassed within the disclosure disclosed and claimed herein.
While the above detailed description has shown, described, and pointed out novel features of the disclosure as applied to various embodiments, it will be understood that various omissions, substitutions, and changes in the form and details of the device or process illustrated may be made by those skilled in the art without departing from the disclosure. This description is in no way meant to be limiting, but rather should be taken as illustrative of the general principles of the disclosure. The scope of the disclosure should be determined with reference to the claims. The specific embodiments and applications thereof described above are for illustrative purposes only and do not preclude modifications and variations encompassed by the scope of the following claims.
This application claims priority to U.S. Provisional Patent Application Ser. No. 62/018,410 filed Jun. 27, 2014 entitled “METHODS AND APPARATUS FOR CONDUCTIVE ELEMENT DEPOSITION AND FORMATION”, as well as U.S. Provisional Patent Application Ser. No. 62/026,560 filed Jul. 18, 2014 entitled “METHODS AND APPARATUS FOR CONDUCTIVE ELEMENT DEPOSITION AND FORMATION”, each of the foregoing incorporated herein by reference in its entirety. This application is related to co-owned and co-pending U.S. patent application Ser. No. 13/782,993 entitled “METHODS AND APPARATUS FOR CONDUCTIVE ELEMENT DEPOSITION AND FORMATION” filed Mar. 1, 2013, which claims priority to U.S. Provisional Patent Application Ser. No. 61/606,320 of the same title filed Mar. 2, 2012, U.S. Provisional Patent Application Ser. No. 61/609,868 of the same title filed Mar. 12, 2012, and U.S. Provisional Patent Application Ser. No. 61/750,207 of the same title filed Jan. 8, 2013, each of the foregoing incorporated herein by reference in its entirety. This application is also related to U.S. patent application Ser. No. 14/620,108 filed Feb. 15, 2015 and entitled “METHODS AND APPARATUS FOR CONDUCTIVE ELEMENT DEPOSITION AND FORMATION”, which claims priority to U.S. Provisional Patent Application Ser. No. 61/939,197 entitled “METHODS AND APPARATUS FOR CONDUCTIVE ELEMENT DEPOSITION AND FORMATION” filed Feb. 12, 2014, each also incorporated herein by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 62018410 | Jun 2014 | US | |
| 62026560 | Jul 2014 | US |
