Flexographic printing

Abstract

A method of flexographic printing includes obtaining a pattern for a flexographic printing plate comprising a region of interest having an outer edge defining a boundary of the region of interest. The method further comprises fabricating a flexographic printing plate using an augmented version of the pattern. The augmented version of the pattern includes additional features added to the pattern. The additional features include features separated from the edge of the region of interest and positioned outside of the region of interest, positioned so as to modify the mechanical properties of the edge. The features separated from the edge of the region of interest mitigate an edge effect of a flexographic printing process. The method includes printing the pattern on a substrate using the flexographic printing plate.

Description

PCT / US24 / 58539 04 December 2024 (04.12.2024)FLEXOGRAPHIC PRINTINGTECHNICAL FIELD

[0001] The embodiments of the present disclosure relate generally to flexographic printing. Some embodiments of the present disclosure relate more specifically to flexographic printing of electronic devices.BACKGROUND

[0002] Flexographic printing involves the transfer of ink from a source (anilox roll) to a substrate via a polymeric stamp (referred to as a flexographic printing plate). The plate is patterned with raised portions in the mirror-image of the shape to be produced. This patterning of the flexographic printing plate is typically created using photo-lithography, where an ultra-violet (UV) lamp illuminates a plate precursor through a photo mask, crosslinking the material in the regions of interest.SUMMARY

[0003] The inventors of the present disclosure have found that, using conventional techniques, defects arise in the process of flexographic printing caused by non-uniform deformation of the flexographic printing plate. Namely, as a simplified example, if one considers a physical model of the plate in which the plate is modelled as a set of springs coupled to each other, then at the surface of the place, where the image is made, the springs at the edges of a raised area do not have nearest neighbors, and their positions are distorted from where they should be. This results in non-uniform height and printing in areas where it is not wanted. The inventors have further found that these edge effects can be mitigated by including, in the flexographic printing plate, a pattern of additional features outside of the region of interest.

[0004] To that end, a method of flexographic printing includes obtaining a pattern for a flexographic printing plate comprising a region of interest having an outer edge defining a boundary of the region of interest. The method further comprises fabricating a flexographic printing plate using an augmented version of the pattern. The augmented version of the pattern includes additional features added to the pattern. The additional features include features103721-5004-WO 1PCT / US24 / 58539 04 December 2024 (04.12.2024) separated from the outer edge of the region of interest and positioned outside of the region of interest, positioned so as to modify the mechanical properties of the outer edge. The features separated from the outer edge of the region of interest mitigate an edge effect of a flexographic printing process. The method includes printing the pattern on a substrate using the flexographic printing plate.

[0005] Further, in some embodiments, a flexographic printing plate includes a raised portion corresponding to a region of interest of a printed pattern, the region of interest having an edge and a plurality of additional features separated from the edge of the region of interest and positioned so as to modify the mechanical properties of the edge to correct for an edge effect of a flexographic printing process.BRIEF DESCRIPTION OF DRAWINGS

[0006] FIG. 1 illustrate a flexography (roll-to-roll processing) setup 100, in accordance with some embodiments.

[0007] FIGS. 2A-2C illustrate cross-sectional views of flexographic printing plates 108, in accordance with some embodiments.

[0008] FIG. 2D illustrates a top-down view of a print, in accordance with some embodiments.

[0009] FIG. 3 illustrates a cross-sectional view of a plate cylinder and a flexographic printing plate, in accordance with some embodiments.

[0010] FIG. 4 illustrates an isometric view of a flexographic printing plate having a border of dots, in accordance with some embodiments.

[0011] FIGS. 5A-5B illustrate cross-sectional views of flexographic printing plates 108 in accordance with some embodiments.

[0012] FIG. 6A illustrates a cross-sectional view of a portion of a flexographic printing plate, in accordance with some embodiments.

[0013] FIG. 6B illustrates a top down view of the flexographic printing plate shown in FIG. 6A, in accordance with some embodiments.103721-5004-WO 2PCT / US24 / 58539 04 December 2024 (04.12.2024)

[0014] FIG. 7 illustrates a top-down view of a flexographic printing plate, in accordance with some embodiments.

[0015] FIG. 8 illustrates example shapes of additional features added to a pattern for a flexographic printing plate, in accordance with some embodiments.

[0016] FIG. 9 illustrates an electronic device (e.g., OLED) at least partially fabricated using the flexographic printing methods described herein, in accordance with some embodiments.

[0017] FIG. 10 illustrates a method of flexographic printing, in accordance with some embodiments.

[0018] Like reference numerals refer to corresponding parts throughout the drawings. The drawings are intended to illustrate the concepts provided in this disclosure, and are thus not drawn to scale.DETAILED DESCRIPTION

[0019] Reference will now be made in detail to embodiments, examples of which are illustrated in the accompanying drawings. In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the various described embodiments. However, it will be apparent to one of ordinary skill in the art that the various described embodiments may be practiced without these specific details. In other instances, well-known methods, procedures, components, circuits, and networks have not been described in detail so as not to unnecessarily obscure aspects of the embodiments.

[0020] FIG. 1 illustrate a flexography (roll-to-roll processing) setup 100, in accordance with some embodiments.

[0021] The flexography setup 100 includes a fountain roller 102. The fountain roller 102 transfers ink located in an ink pan 104 to an anilox roller 106. In modern flexographic printing, the anilox roller 106 is sometimes referred to as a metering roller.

[0022] The anilox roller 106 is responsible for transferring ink to a flexographic printing plate 108 (a flexible plate) mounted on a plate cylinder 110. In some embodiments, the anilox roller 106 transfers a uniform thickness of ink to a flexographic printing plate 108 mounted on a103721-5004-WO 3PCT / US24 / 58539 04 December 2024 (04.12.2024) plate cylinder 110 (e.g., the anilox roller 106 has finely engraved cells with a particular ink capacity). In some embodiments, an optional doctor blade 114 scrapes the anilox roller 106 to ensure that the ink to be delivered to the flexographic printing plate 108 is only what is contained within the engraved cells.

[0023] In some embodiments, the flexographic printing plate 108 is made from a soft flexible rubber-like material. In some embodiments, the flexographic printing plate 108 is held to the plate cylinder 110 using a mounting adhesive tape 112. In other embodiments, the flexographic printing plate 108 is held to the plate cylinder 110 using magnets, tension straps, and / or ratchets.

[0024] The flexography setup 100 further includes an impression cylinder 116 (also called a “print anvil”) that applies pressure to the plate cylinder 110. In this manner, an ink image of the flexographic printing plate 108 is transferred to the printing substrate 118. In some embodiments, the ink is a solution from which a respective layer in a stack of electronic layers is formed (e.g., any of the layers described with respect to FIG. 9). In some embodiments, the printing substrate 118 is used as the substrate for an electronic device, described below.

[0025] FIGS. 2A-2C illustrate cross-sectional views of flexographic printing plates 108. FIG. 2D illustrates a top-down view of a print. FIGS. 2A-2C illustrate the edge effects that arise at the boundaries of raised portions of a flexographic printing plate 108. As noted above, flexographic printing involves the transfer of ink from a source (anilox roll) to a substrate via a polymeric stamp (e.g., flexographic printing plate 108). The flexographic printing plate 108 is patterned with raised portions in the mirror-image of the shape to be produced (e.g., raised portion 208 corresponds to a region of interest of a printed pattern having an edge 209). Thus, the raised portions 208 correspond to regions of interest in the printed pattern (e.g., regions in which a printed area is desired), as the raised portions 208 are the portions of the flexographic printing plate that transfer ink to the substrate, as described above. This patterning of the flexographic printing plate 108 is created using photo-lithography, where a UV lamp illuminates the plate precursor through a photo mask, crosslinking the material in the regions of interest. The flexographic printing plate 108 is then developed, and the unexposed areas are washed away. The idealized result is shown in FIG. 2A, where the raised portions are raised a height h 218 above the “land” and are flat and tapered to the “land” below at an angle x 216 determined by the103721-5004-WO 4PCT / US24 / 58539 04 December 2024 (04.12.2024) angles of light rays from exposure equipment. FIG. 2B illustrates examples of defects that arise in the process, where shrinkage from the UV crosslinking step creates “cat ears” 210 at the edges of the raised print. Even in the idealized case, the quick transition from raised print area to the thinner land area results in discontinuous mechanical properties at that interface, which affects the way the flexographic printing plate 108 conforms to the plate cylinder it is mounted on, as well as how it deforms as it is compressed during the inking and print transfer processes.

[0026] As shown in FIG. 2C, when the plate is pressed against another surface 214 (as during printing), the cat ears 210 are pushed down, rolling the edge and causing contact with the sloped sides of the print area, resulting in the “donut defect” 212 - a ring around the perimeter of the print (also shown in a top down view in FIG. 2D, denoted by a thick solid line). This is generally not a problem with graphic image printing, where images are made from halftone dots (and thus the distortions are difficult to discern with the naked eye), but this problem is more significant when printing solids, as frequently occurs when making electronics such as large areas of conductive, resistive, or semi-conductive materials. For example, in the case of an OLED printed using the flexographic processes described herein, portions of the donut defect 212 could become illuminated when the OLED is turned on, resulting in an obvious an unsightly distortion of the border of the (desired) illuminated area.

[0027] FIG. 3 illustrates a cross-sectional view of a plate cylinder 110 and a flexographic printing plate 108. In particular, FIG. 3 illustrates another mechanism by which ink can be deposited in a buildup around the edge of the printed region of interest. Here, the cause is due to the discontinuous change in elastic properties of the plate. The thicker (and therefore stiffer) raised portions 208 tend to stand proud from the plate cylinder at transitions to the thin areas due to stress concentration in the thinner areas. As the cylinder rotates and is inked and printed, these protrusions can result in wetting and ink transfer from the sloped surface outside of the intended print area. Because the protrusions happen at the transition between thick and thin areas of the plates, they effectively behave in a way similar to the “cat ears” described with reference to FIGS. 2A-2D.

[0028] FIG. 4 illustrates an isometric view of a flexographic printing plate 108 having a border of dots, in accordance with some embodiments. The dots 402 in FIG. 4 are an example of a plurality of additional features separated from the edge 209 of a raised portion 208103721-5004-WO 5PCT / US24 / 58539 04 December 2024 (04.12.2024) corresponding to a region of interest and positioned so as to modify the mechanical properties of the edge 209 to correct for edge effect(s) of a flexographic printing process (e.g., the edge effects discussed with reference to the previous features). In particular, FIG. 4 illustrates the additional features added to a flexographic printing plate to mitigate the edge effects described above. In particular, in some embodiments, these problems are addressed by creating a perimeter of features (e.g., dots) at a fixed distance from the intended print area, referred to as a dot border, which is outside of the so-called “intended print area.” This dot border is characterized by the dot diameter, the inter-dot spacing, and the distance from the edge of the intended print to the perimeter of dots. The dots function to effectively move the transition area effects away from the intended print area by slowing the transition from the thick to thin parts of the plate.

[0029] FIGS. 5A-5B illustrate cross-sectional views of flexographic printing plates 108 in accordance with some embodiments. As shown in FIG. 5A-5B, regarding the “cat ears,” the presence of the dots 402 provides a crosslinked polymer outside of the edge of the print to balance the tension from the crosslinked area at the edge of the print that would otherwise have no nearest neighbor (and would curl upward as a result). In particular, as shown in FIG. 5A, without a dot nearby, the tension in the crosslinked area pulls the surface into a “cat ear” shape. In contrast, as shown in FIG. 5B, with a nearest neighbor dot 402, the tension is balanced, preserving print quality within the intended print area.

[0030] FIG. 6A illustrates a cross-sectional view of a portion of a flexographic printing plate 108, in accordance with some embodiments. As shown in FIG. 6A, the dots 402 (e.g., dot 402A, 402B, and 402C) also serve to create a more continuous transition from raised (and, concomitantly, thick and stiff) to the non-raised and (concomitantly, thinner and less stiff), as they are not a solid pattern. Thus, the region of the flexographic printing plate 108 that contains the dots has an effective stiffness between those of the solid and empty areas. When wrapped on the surface of a cylinder, the flexographic printing plate 108 conforms more smoothly because the discontinuities in stiffness are alleviated.

[0031] FIG. 6B illustrates a top down view of the flexographic printing plate 108 shown in FIG. 6A. In particular, FIGS. 6A-6B illustrate an embodiment in which there are several layers of dots 602 (e.g., layer 602A, 602B, and 602C), each layer 602 having a different distance from the intended print area and each adjacent pair of layers having a different inter-dot spacing103721-5004-WO 6PCT / US24 / 58539 04 December 2024 (04.12.2024)(e.g., the first layer is a first distance from the intended print area, the second layer is a second distance, greater than the first distance, from the first layer, and the third layer is a third distance, greater than the second distance, from the second layer). More particularly, the additional features (e.g., dots) in FIG. 6B comprise a plurality of sets of additional features (e.g., sets of dots 602), including a first set of additional features (first set of dots 602A) having (e.g., characterized by) a first mean distance LI from the region of interest (e.g., from the edge of the region of interest) and a second set of additional features (second set of dots 602A) that have a second mean distance L2 from the region of interest. The difference between the second mean distance and the first mean distance (L2-L1) is greater than the first mean distance (LI). FIG. 6B also shows a third set of dots 602C characterized by a third mean distance L3 from the region of interest. The difference between the third mean distance and the second mean distance (L3-L2) is greater than the difference between the second mean distance and the first mean distance (L2- Ll). In other words, the sets of additional features have increasingly larger spacing from the region of interest as the sets are positioned farther from the region of interest. In some embodiments, however, the spacing between sets of additional features is substantially uniform.

[0032] Similarly, in the example shown in FIG. 6B, the first set of additional features (first set of dots 602A) is characterized by a first mean spacing SI between respective adjacent features in the first set of features and the second set of additional features (second set of dots 602B) is characterized by a second mean spacing S2 between adjacent features in the second set of features. The second mean spacing S2 is greater than the first mean spacing SI. In some embodiments, the third set of features (third set of dots 602C) is characterized by a third mean spacing L3 that is greater than the second mean spacing (L2). In other words, in some embodiments, the sets of additional features have increasingly larger spacing between adjacent features as the sets are positioned farther from the region of interest, thus further smoothing the transition in the mechanical properties. In some embodiments, however, the spacing between additional features is substantially constant between the sets of additional features.

[0033] In some embodiments, the first set of additional features are separated from the region of interest by a horizontal distance that is less than 2 x / tan (x). where x is a taper angle of the flexographic printing plate and h is a height of a raised portion of the flexographic printing plate (see FIG. 2A for an illustration of the height and angle). That is to say, in some embodiments, the additional features are positioned such that the taper does not reach “land” in103721-5004-WO 7PCT / US24 / 58539 04 December 2024 (04.12.2024) the flexographic printing plate 108. In some embodiments, the spacing between sets of features is less than 2 x / tan (x). In some embodiments, the spacing between adjacent features is less than 2 X h / tan (x).

[0034] Note that FIG. 6B illustrates an example in which the sets of dots 602 each have a substantially uniform distance from the edge 209, and thus the mean spacing is equivalent to the substantially uniform spacing, although this need not be the case. Likewise, FIG. 6B also illustrates an example in which the spacing between adjacent dots (the interdot spacing) is also substantially uniform, and thus the mean dot spacing is equivalent to the substantially uniform interdot spacing, although this also need not be the case. FIG. 6B illustrates an example in which the additional features are positioned only on one edge of the region of interest (raised portion 208), although as shown in FIG. 7, in some embodiments or circumstances, additional features can be positioned off of multiple edges (e.g., surrounding the entire region of interest).

[0035] FIG. 7 illustrates a top-down view of a flexographic printing plate 108 in accordance with some embodiments. In particular, FIGS. 6A-6B and 7 illustrate that the inter-dot spacing along the perimeter line can also be increased with each successive row of dots, in accordance with some embodiments, creating a reduction in stiffness along both axes in the plane of the material.

[0036] FIG. 8 illustrates example shapes of additional features added to a pattern for a flexographic printing plate, in accordance with some embodiments. The example shapes include square dots 802, rectangular dots 804, crosses 806, diamonds 808, circles 810, ellipses 812, and an n-sided polygon 814 (in this example an eight-sided polygon).

[0037] FIG. 9 illustrates an electronic device (e.g., OLED) at least partially fabricated using the flexographic printing methods described herein, in accordance with some embodiments. In FIG. 9, a stack of layers 902 is provided that includes a substrate 904 and one or more electronically -active layers disposed on a surface of the substrate. For example, one or more of layer 906a, layer 906b, and layer 906c are electronically-active layers (e.g., a hole injection layer, hole transport layer, light emission layer, electronic transport layer, electron injection layer). In some embodiments, one or more of the layers 906 are fabricated using the flexographic printing processes described herein, although one or more of these layers may be fabricated using other methods as well (e.g., sputtering, chemical vapor deposition, etc ). A103721-5004-WO 8PCT / US24 / 58539 04 December 2024 (04.12.2024) printed layer 908 is applied using the flexographic printing methods described herein over the stack of layers 902. Thus, the printed layer 908 includes the additional features described throughout this disclosure. The additional features are, however, electrically isolated from the main stack of layers in the OLED, such that when the OLED is turned on, the additional features do not emit light and are not especially noticeable to an observer viewing the OLED. This can be particularly important, for example, when printing OLEDs to represent particular shapes (e.g., a sign with illuminated letters or illustrations).

[0038] One of skill in the art, having the benefit of this disclosure, will appreciate that the flexographic printing processes described herein may also be used to fabricate layers of other types of electronic devices, including other types of electro-optical devices (such as solar cells).

[0039] FIG. 10 illustrates a method 1000 of flexographic printing, in accordance with some embodiments.

[0040] Method 1000 includes obtaining (1002) a pattern for a flexographic printing plate (e.g., as a CAD or GDS file) comprising a region of interest having an outer edge defining a boundary of the region of interestFor example, the edge is not internal to the region of interest, meaning that the edge is not within an intended print area, and thus, outside of the boundary is outside of the intended print area). For example, if the pattern included the letter O, the internal unprinted region of the O would still be considered external to the region of interest, because the region of interest is the solid portion corresponding to the printed “O.” Thus, the techniques described herein may be used to improve the interior edge of the “O,” which is still considered an outer edge of the boundary of the region of interest. This is in contrast to certain flexographic printing technique, which may be used in tandem with the principles of the current disclosure, in which an internal dot structure is used within the region of interest to modify print properties.

[0041] In some circumstances, the pattern may include a plurality of regions of interest (e.g., the pattern may spell out letters or illustrations), each having a boundary and an outer edge. In these circumstances, method 1000 may be applied to each, or at least more than one, outer edge (boundary) of the plurality of regions of interest.

[0042] Method 1000 includes fabricating (or otherwise obtaining) (1004) a flexographic printing plate (e.g., lithographically) using an augmented version of the pattern. The augmented version of the pattern includes additional features added to the pattern (e.g., the method includes103721-5004-WO 9PCT / US24 / 58539 04 December 2024 (04.12.2024) adding the additional features to the pattern, e.g., by adding the features to the CAD or GDS file storing the pattern). The additional feature include features separated from the edge of the region of interest and positioned outside of the region of interest, positioned so as to modify the mechanical properties of the edge. The features separated from the edge of the region of interest mitigate an edge effect of a flexographic printing process.

[0043] Note that the pattern for the flexographic printing plate and the flexographic printing plate itself include certain analogous features. For example, a region of interest having an edge in the pattern results in a region of interest (raised portion) in the flexographic printing plate, also having an edge. It should be clear from context, throughout this disclosure, whether a certain feature being referred to is that of the pattern or the flexographic printing plate.

[0044] In some embodiments, method 1000 includes augmenting the obtained pattern to include the additional features (e.g., modifying the CAD or GDS file).

[0045] In some embodiments, the additional features comprise one or more of the group consisting of: square dots, rectangular dots, crosses, diamonds, and an n-sided polygon (e.g., as shown in FIG. 8).

[0046] In some embodiments, the additional features comprise a plurality of sets of additional features (e.g., rows of additional features), including a first set of additional features having a first mean distance from the region of interest (e.g., a first row positioned a first distance from the edge) and a second set of additional features that have a second mean distance from the region of interest (e.g., a second row positioned a second distance from the edge). The difference between the first mean distance and the second mean distance is greater than the first mean distance (e.g., the first row is spaced closer to the edge than the second row is to the first row).

[0047] In some embodiments, the first set of additional features is characterized by a first mean spacing between respective adjacent features in the first set of features and the second set of additional features is characterized by a second mean spacing between adjacent features in the second set of features (e.g., the interdot spacing is different in different rows of additional features).103721-5004-WO 10PCT / US24 / 58539 04 December 2024 (04.12.2024)

[0048] In some embodiments, the second mean spacing is greater than the first mean spacing (e.g., the interdot spacing becomes larger as the features are farther from the edge). In some embodiments, the second mean spacing is less than the first mean spacing (e.g., the interdot spacing becomes smaller as the features are farther from the edge).

[0049] In some embodiments, the additional features are separated from the region of h interest by a horizontal distance that is less than 2 x — — where x is a taper angle of theflexographic printing plate and h is a height of a raised portion of the flexographic printing plate (e.g., relative to “land”). Stated another way, in some embodiments, the additional features as separated by a distance that is less than what would be required for the taper to reach “land.”

[0050] Method 1000 includes printing (1006) the pattern on a substrate using the flexographic printing plate. In some embodiments, printing the pattern includes printing areas corresponding to the additional features. Alternatively, in some embodiments, some or all of the additional features on the flexographic plate are too small and / or too sparse to result in printed regions. For example, in some embodiments, the additional features in the augmented version of the pattern are sufficiently small such that, when the flexographic printing plate is fabricated (e.g., lithographically), the features do not reach the full height of the raised portions of the flexographic printing plate, but nonetheless modify the mechanical properties of the printing plate so as to alleviate the edge effects described herein. More particularly, in some embodiments, the pattern is augmented to include features that, as intended, are smaller than can be fully resolved into printed dots using flexographic printing plate fabrication techniques, but nevertheless yield limited exposure of the photopolymer that result in thicker mounds on the plate surface that are less than the height of the printing surface. The inventors have found that, when the pattern includes individual islands of sufficiently small dots (sufficiently far from nearest neighbors and sufficiently small in diameter), the result is that there is not enough light in that part of the photomask to produce a fully formed dot / pyramid / cone to the full height of the plate. Instead, the resulting fabricated flexographic printing plate includes a rounded “mound,” corresponding to each of such dots, at less than the full height. In some embodiments, such dots are used for some or all of the “additional features” described herein, resulting in plate-stiffening without actually printing the dots into the final product.103721-5004-WO 11PCT / US24 / 58539 04 December 2024 (04.12.2024)

[0051] In some embodiments, printing the pattern on a substrate using the flexographic printing plate comprises printing a conductive layer in an electronic device. In some embodiments, the electronic device is an organic light emitting diode, solar cell, or other electro- optical device.

[0052] In some embodiments, the printed pattern includes printed areas corresponding to the additional features that are isolated (e.g., electrically isolated) from any printed areas corresponding to the obtained pattern. For example, in the case of an OLED, the printed areas corresponding to the additional features are not illuminated when the OLED is turned on, and thus are not particularly noticeable to an observer of the OLED.

[0053] In some embodiments, the step of fabricating the flexographic printing plate may be performed by a third-party. Thus, in some embodiments, a method includes obtaining a pattern for a flexographic printing plate (e.g., as a CAD or GDS file) comprising a region of interest having an outer edge defining a boundary of the region of interest. The method further includes printing a pattern on a substrate using a flexographic printing plate. The flexographic printing plate includes an augmented version of the pattern. The augmented version of the pattern includes additional features added to the pattern. The additional features include features separated from the edge of the region of interest and positioned outside of the region of interest, positioned so as to modify the mechanical properties of the edge. The features separated from the edge of the region of interest mitigate an edge effect of a flexographic printing process. The method may include any of the features of method 1000, described above. In this method, the step of fabricating the printing plate may be performed by a third-party, and is thus optional.

[0054] In some embodiments, a method includes obtaining a pattern for a flexographic printing plate (e.g., as a CAD or GDS file) comprising a region of interest having an outer edge defining a boundary of the region of interest. The method includes fabricating a flexographic printing plate (e.g., lithographically) using an augmented version of the pattern. The augmented version of the pattern includes additional features added to the pattern. The additional features include features separated from the edge of the region of interest and positioned outside of the region of interest, positioned so as to modify the mechanical properties of the edge. The features separated from the edge of the region of interest mitigate an edge effect of a flexographic103721-5004-WO 12PCT / US24 / 58539 04 December 2024 (04.12.2024) printing process. In this method, the step of printing may be performed by a third-party, and is thus optional.

[0055] Note that the embodiments of the present disclosure generally relate to features (e.g., dots) that are added to a flexographic printing plate 108 outside of a region of interest (also referred to as an intended print area). One of skill in the art, having the benefit of this disclosure, will understand that these embodiments may be combined with various techniques for improving the quality of flexographic printing by altering the structure of the flexographic printing plate 108 within the intended print area. Such methods are described, for example, in U.S. Patent Publication 2016 / 0221379.

[0056] The foregoing description, for purposes of explanation, has been described with reference to specific embodiments. However, the illustrative discussions above are not intended to be exhaustive or to limit the invention to the precise forms disclosed. Many modifications and variations are possible in view of the above teachings. The embodiments were chosen and described in order to best explain the principles of the invention and its practical applications, to thereby enable others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated.

[0057] It will be understood that, although the terms “first,” “second,” etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first instance of a layer of material could be termed a second instance of the layer of material, and, similarly, a second first instance of the layer of material could be termed a first instance of the layer of material, without changing the meaning of the description, so long as all occurrences of the “first instance of the layer of material” are renamed consistently and all occurrences of the “second instance of the layer of material” are renamed consistently. The first instance of the layer of material and the second fist instance of the layer of material are both instances of the layer of material, but they are not the same instance of the layer of material.

[0058] The terminology used herein is for the purpose of describing particular implementations only and is not intended to be limiting of the claims. As used in the description of the implementations and the appended claims, the singular forms “a,” “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will103721-5004-WO 13PCT / US24 / 58539 04 December 2024 (04.12.2024) also be understood that the term “and / or” as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items. It will be further understood that the terms “comprises” and / or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0059] As used herein, the term “if’ may be construed to mean “when” or “upon” or “in response to determining” or “in accordance with a determination” or “in response to detecting,” that a stated condition precedent is true, depending on the context. Similarly, the phrase “if it is determined [that a stated condition precedent is true]” or “if [a stated condition precedent is true]” or “when [a stated condition precedent is true]” may be construed to mean “upon determining” or “upon a determination that” or “in response to determining” or “in accordance with a determination” or “upon detecting” or “in response to detecting” that the stated condition precedent is true, depending on the context.103721-5004-WO 14

Claims

PCT / US24 / 58539 04 December 2024 (04.12.2024)WHAT IS CLAIMED IS:

1. A method of flexographic printing, comprising: obtaining a pattern for a flexographic printing plate comprising a region of interest having an outer edge defining a boundary of the region of interest; and fabricating a flexographic printing plate using an augmented version of the pattern, the augmented version of the pattern including additional features added to the pattern, the additional features comprising features separated from the outer edge of the region of interest and positioned outside of the region of interest, positioned so as to modify mechanical properties of the outer edge, wherein the features separated from the edge of the region of interest mitigate an edge effect of a flexographic printing process; and printing the pattern on a substrate using the flexographic printing plate.

2. The method of claim 1, wherein the additional features comprise one or more of the group consisting of: square dots, rectangular dots, circles, ellipses, crosses, diamonds, and an n- sided polygon.

3. The method of claim 1, wherein the additional features comprise a plurality of sets of additional features, including a first set of additional features having a first mean distance from the region of interest and a second set of additional features that have a second mean distance from the region of interest.

4. The method of claim 3, wherein the difference between the first mean distance and the second mean distance is greater than the first mean distance.

5. The method of claim 3, wherein the difference between the first mean distance and the second mean distance is less than the first mean distance.

6. The method of claim 3, wherein the first set of additional features is characterized by a first mean spacing between respective adjacent features in the first set of features and the second103721-5004-WO 15PCT / US24 / 58539 04 December 2024 (04.12.2024) set of additional features is characterized by a second mean spacing between adjacent features in the second set of features.

7. The method of claim 6, wherein the second mean spacing is greater than the first mean spacing.

8. The method of claim 6, wherein the second mean spacing is less than the first mean spacing.

9. The method of claim 1, wherein printing the pattern on a substrate using the flexographic printing plate comprises printing a conductive layer in an electronic device.

10. The method of claim 9, wherein the electronic device is an organic light emitting diode.

11. The method of claim 1, wherein the printed pattern includes printed areas corresponding to the additional features that are isolated from any printed areas corresponding to the obtained pattern.

12. The method of claim 1, wherein the additional features are separated from the region of h. interest by a horizontal distance that is less than 2 Xtan( where x is a taper angle of the flexographic printing plate and h is a height of a raised portion of the flexographic printing plate.

13. A flexographic printing plate, comprising: a raised portion corresponding to a region of interest of a printed pattern, the region of interest having an edge; and a plurality of additional features separated from the edge of the region of interest and positioned so as to modify the mechanical properties of the edge to correct for an edge effect of a flexographic printing process.

14. The flexographic printing plate of claim 13, wherein the additional features comprise one or more of the group consisting of: square dots, rectangular dots, circles, ellipses, crosses, diamonds, and an n-sided polygon.

15. The flexographic printing plate of claim 13, wherein the additional features comprise a plurality of sets of additional features, including a first set of additional features having a first103721-5004-WO 16PCT / US24 / 58539 04 December 2024 (04.12.2024) mean distance from the region of interest and a second set of additional features that have a second mean distance from the region of interest.

16. The flexographic printing plate of claim 15, wherein the difference between the first mean distance and the second mean distance is greater than the first mean distance.

17. The flexographic printing plate of claim 15, wherein the difference between the first mean distance and the second mean distance is less than the first mean distance.

18. The flexographic printing plate of claim 15, wherein the first set of additional features is characterized by a first mean spacing between respective adjacent features in the first set of features and the second set of additional features is characterized by a second mean spacing between adjacent features in the second set of features.

19. The flexographic printing plate of claim 18, wherein the second mean spacing is greater than the first mean spacing.

20. The flexographic printing plate of claim 18, wherein the second mean spacing is less than the first mean spacing.

21. The flexographic printing plate of claim 13, wherein the additional features are separated from the region of interest by a horizontal distance that is less than 2 x h / tan(x), where x is a taper angle of the flexographic printing plate and h is a height of a raised portion of the flexographic printing plate.103721-5004-WO 17

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