Security device with controlled viewpoint validation

Abstract

A micro-optic device includes an array of focusing elements (205), wherein each focusing element of the array of focusing element has a footprint, a first set of image icons (220), wherein image icons of the first set of image icons comprise regions of directionally cured light curable material which occupy a first subset of locations (411) within footprints of the array of focusing elements, and a second set of image icons (299), wherein the second set of image icons occupy a second subset of locations within footprints of the array of focusing elements, the second set of image icons project a second image (320). When viewed through the array of focusing elements across a first predetermined range of viewing angles, the first set of image icons projects a first image (305). The first image is not detectable by an on-axis imaging apparatus.

Description

SECURITY DEVICE WITH CONTROLLED VIEWPOINT VALIDATIONTECHNICAL FIELD

[0001] The present disclosure relates to enhancing security documents, such as currency notes, passports and other documents comprising surface-applied micro-optic security devices by providing static features which can be reliably read and authenticated by smartphones, tablets, and other consumer-level imaging apparatus, but which are generally invisible to flatbed scanners and other single-axis document imaging tools of the sort preferred by counterfeiters and other malicious actors to obtain high resolution scans of valid documents for counterfeiting. More specifically, this disclosure relates to a security document with controlled viewpoint validation and methods for producing same.BACKGROUND

[0002] Manufacturing passports, banknotes, and other documents (referred to herein as “security documents”) whose constructional features include hard-to-reproduce indicia of the documents’ authenticity against counterfeiting remains an ongoing source of technical challenges and opportunities for improvement in the field of security document design.

[0003] One of the principal and persistent challenges in the field of security document design is designing and manufacturing security features (for example, micro-optic security threads or patches) which have indicia of authenticity which are simultaneously: visually striking for example, image content that “magically” appears to move and / or have three-dimensional depth; are difficult for malicious actors to reproduce; and are rugged enough to withstand circulation, folding and other structural rigors of everyday use. Micro-optic security devices which comprise a first layer of lenses superimposed over a second layer of icon elements, and which operate through the lenses’ orchestrating, magnifying and / or restricting a user’s view of the icon elements, have been and continue to be, one of the best available solutions for simultaneously achieving visual distinctiveness, ruggedness, and resistance to counterfeiting.

[0004] Skilled artisans will appreciate that improvements in the availability of specialized inks, printers, and imaging tools, in combination with the appeal of illegitimate gains, have engendered a neverending arms race between manufacturers and counterfeiters, wherein the former must continually strive to develop new security devices embodying the three key requirements of detectability, irreproducibility and durability. Improvements to date and expected improvements in the resolution and quality of flatbed scanners and other commercial document scanners present a source of particular concern. While, historically, there had been enough disparity in the resolution of imaging devices relative to the resolution of micro-features of security documents to reliably introduce tell-tale “beat” or moire effects in counterfeits based on scans of original documents, improvements in consumer-level imaging apparatus have made this increasingly less the case. Further, improvements in imaging technology point towards a future in which imaging apparatuses capable of resolving detail in the icon layer may become available to counterfeiters and other malicious actors.

[0005] Accordingly, the challenge associated with developing micro-optic security devices vis to provide features that can be detected at a macro level by a user’s eye, or better yet, widely available devices such as smartphones or tablets, but which cannot easily be imaged using a flatbed scanner or other tools for detailed imaging analysis. Additionally, the technical challenges associated with “staying ahead” of malicious actors further include encoding unique, or serialized indicia of authenticity into visible features in a way that, even if perfectly reproduced, limits the number of passable counterfeit documents a malicious actor can produce. For example, a security device with an encoded serial number provided as a QR code directed to the web address of an authentication body may be able to identify compromised or counterfeit serial numbers. For example, the circumstances of QR code checks on the same number can provide leads as to the presence and location of forged documents. As one example, if validity checks of a serialized QR code are performed over a short interval from geographically distant IP addresses, this can strongly suggest that one or more counterfeit copies are in circulation. Similarly, if the QR code check statistics on a particular serial number are statistically inconsistent (i.e., too many checks being received) relative to other documents, this, too can be evidence of counterfeiting.SUMMARY

[0006] The present disclosure relates to a security document with controlled viewpoint validation and methods for producing same.

[0007] In a first embodiment, a micro-optic device includes an array of focusing elements, wherein each focusing element of the array of focusing element has a footprint. The micro-optic device also includes a first set of image icons, wherein image icons of the first set of image icons comprise regions of directionally cured light curable material which occupy a first subset of locations within footprints of the array of focusing elements. The micro-optic device includes a second set of image icons, wherein the second set of image icons occupy a second subset of locations within footprints of the array of focusing elements and the second set of image icons project a second image. When viewed through the array of focusing elements across a first predetermined range of viewing angles, the first set of image icons projects a first image. The first image is not detectable by an on-axis imaging apparatus.

[0008] In a second embodiment, a method of creating a micro-optic device includes providing an array of focusing elements, wherein each focusing element of the array of focusing elements has a footprint. The method further includes providing a first set of image icons, wherein image icons of the first set of image icons comprise regions of directionally cured light curable material which occupy a first subset of locations within footprints of the array of focusing elements. Additionally, the method includes providing a second set of image icons, wherein the second set of image icons occupy a second subset of locations within footprints of the array of focusing elements, the second set of image icons projecting a second image. When viewed through the array of focusing elements across a predetermined first range of viewing angles, the first set of image icons projects a first image. The first image is not detectable by an on-axis imaging apparatus.

[0009] Other technical features may be readily apparent to one skilled in the art from the following figures, descriptions, and claims.

[0010] Before undertaking the DETAILED DESCRIPTION below, it may be advantageous to set forth definitions of certain words and phrases used throughout this patent document. The term “couple” and its derivatives refer to any direct or indirect communication between two or more elements, whether or not those elements are in physical contact with one another. The terms “include” and “comprise,” as well as derivatives thereof, mean inclusion without limitation. The term “or” is inclusive, meaning and / or. The phrase “associated with,” as well as derivatives thereof, means to include, be included within, interconnect with, contain, be contained within, connect to or with, couple to or with, be communicable with, cooperate with, interleave, juxtapose, be proximate to, be bound to or with, have, have a property of, have a relationship to or with, or the like. The phrase “at least one of,” when used with a list of items, means that different combinations of one or more of the listed items may be used, and only one item in the list may be needed. For example, “at least one of: A, B, and C” includes any of the following combinations: A, B, C, A and B, A and C, B and C, and A and B and C.

[0011] Definitions for other certain words and phrases are provided throughout this patent document. Those of ordinary skill in the art should understand that in many if not most instances, such definitions apply to prior as well as future uses of such defined words and phrases.BRIEF DESCRIPTION OF THE DRAWINGS

[0012] For a more complete understanding of the present disclosure and its advantages, reference is now made to the following description taken in conjunction with the accompanying drawings, in which like reference numerals represent like parts:

[0013] FIGURE 1 illustrates an example of a security document according to some embodiments of this disclosure;

[0014] FIGURES 2A through 2C illustrates examples of security devices according to various embodiments of this disclosure;

[0015] FIGURES 3A and 3B illustrate examples of a device providing controlled viewpoint validation according to some embodiments of this disclosure;

[0016] FIGURES 4A and 4B illustrate examples of methods for forming image icons provide controlled viewpoint validation according to various embodiments of this disclosure;

[0017] FIGURES 5A-5I illustrate embodiments of micro-optic security devices with machine-readable indicia of authenticity with controlled viewpoints;

[0018] FIGURES 6A and 6B illustrate examples of dividing views of a machine-readable indicia of authenticity across predetermined ranges of viewing angles;

[0019] FIGURE 7 illustrates an example of a method for authenticating a security document according to certain embodiments of this disclosure; and

[0020] FIGURE 8 illustrates an example of a method of making security features according to certain embodiments of this disclosure.DETAILED DESCRIPTION

[0021] FIGURES 1 through 8, discussed below, and the various embodiments used to describe the principles of the present disclosure are by way of illustration only and should not be construed in any way to limit the scope of the disclosure. Those skilled in the art will understand that the principles of the present disclosure may be implemented in any suitably arranged security document.

[0022] Although the present disclosure has been described with various embodiments, various changes and modifications may be suggested to one skilled in the art. It is intended that the present disclosure encompass such changes and modifications as falling within the scope of the claims.

[0023] FIGURE 1 illustrates an example of a security document according to certain embodiments of this disclosure.

[0024] Referring to the non-limiting example of FIGURE 1, an example of a security document 100 according to various embodiments of this disclosure is shown. In this illustrative example, security document 100 is a currency note, though other embodiments (for example, tickets, identification papers, etc.) are within the contemplated scope of this disclosure. According to some embodiments, security document 100 comprises a substrate 105, which is formed from a wet web of fibrous material (for example, wood pulp, cotton fiber, linen fiber, flax fiber, sisal fiber, hemp fiber, Abaca fiber, Kozo fiber, Mitsumata fiber, bamboo fiber, Kenaf fiber and or synthetic fiber), which is laid down (for example, in a Fourdrinier process) at a first, baseline fiber density. Regions of the web in which the first fiber density is not altered while the web is wet (for example, through the use of wire rolls, electrotypes, or other watermarking tools) prior to pressing, drying and in some embodiments, calendaring, form bulk regions 110 of security document 100. As used in this disclosure, the expression “bulk region” encompasses a portion of a fibrous substrate embodying one or more of a baseline fiber density, baseline light absorption, or baseline caliper thickness. Put differently, as used in this disclosure, the expression “bulk region” encompasses portions of a finished fibrous substrate in which the locations of the constituent fibers are not deliberately altered (for example, through the use of embossed wirecloth or electrotypes) as part of the papermaking process.

[0025] While, for many species of security documents, fibrous materials are the default material for substrate 105, the user of polymeric sheets (for example, sheets of polypropylene or variants thereof, such as biaxially oriented polypropylene (“BOPP”)), are possible, and within the contemplated scope of this disclosure. Depending on the application, there may not be any specific requirement that substrate 105 be a thin, flexible, section of fibrous or polymeric material. In some applications, substrate 105 can be a rigid, smooth surface of an object that is a potential counterfeiting target (for example, the metal case back of a wristwatch, or a perfume bottle) to which security feature 115 can be durably adhered to provide some indicia of authenticity.

[0026] As shown in the explanatory example of FIGURE 1, security document 100 further comprises one or more security features 115 adhered to the surface of security document 100. Security feature 115 comprises a thin section of material with one or more optical structures, such as structures comprising an embossed or cast-cured outer surface that provides an optically variable effect. Examples of opticalstructures provided on security feature 115 include, without limitation, micro-lenses, diffractive structures, and micro-optic icons. Examples of optically variable effects provided by the optical structures of security feature 115 include, without limitation, holograms, color shift effects, and synthetic images, characterized by the synthetic projection of portions of image icons across an array of image icons by focusing elements of an array of focusing elements, wherein the scale ratio (i.e., the ratio of the repeat period of the focusing elements to the repeat period of the image icons) is approximately 1.000. As discussed elsewhere herein, security feature 115 provides, through the projection of content in the micro-optic icon layer, at least one image which is visible at a predetermined angle which is not perpendicular to the surface of security document 100. The overwhelming bulk of high-resolution document scanners operate by placing the document to be scanned on a transparent platen performing a raster scan by advancing a line scanner parallel to the platen. Such scanners only collect image data from a single viewpoint perpendicular to the platen and scanned document (i.e., the line scanner is necessarily looking straight at the document). Certain embodiments according to this disclosure leverage the fact while modem scanners can achieve very high imaging resolution images, such images are almost always captured from a top-dead-center, or “on-axis” perspective. Put differently, the manner and mode of modem scanners’ operation generally precludes them from imaging any content only visible from off-perpendicular axis perspectives. As discussed in greater detail herein, certain embodiments according to this disclosure provide enhanced indicia of authenticity by hiding image at locations in the icon layer that are in the blind spots of most document scanners, but readily visible to human users and popular devices obtaining off-axis views of security document 100.

[0027] Security document 100 may comprise one or more functional watermarks 120. According to various embodiments, functional watermarks 120 comprise one or more regions in which the fiber density of substrate 105 is deliberately altered (either increased or decreased) from the fiber density in bulk region 110 to form a visible pattern of light (i.e., allowing more light to pass in transmission through the fibrous substrate than bulk region 110) and / or dark (i.e., less light to pass in transmission through the fibrous substrate than bulk region 110) elements. Additionally, at least a portion of functional watermark 120 can be covered by part of security feature 115, wherein security feature 115 is maintained in contact with functional watermark 120 by an adhesive bond. According to various embodiments, functional watermark 120 contacting security feature 115 comprises one or more light or dark elements with edges that are substantially perpendicular to one or more peel directions 125 of security feature 115. As used in this disclosure, the expression “peel direction” encompasses a direction in which the separation of security feature 115 is propagated in a direction generally corresponding a local minimum of the separation line. By lifting security feature 115 away from substrate 105 in a peel direction 125 substantially perpendicular to a separation line between security feature 115 and substrate 105, the total peeling force applied to substrate 105 is minimized. All other things being equal, malicious actors may be reasonably expected to attempt to harvest security feature 115 by separating security feature 115 from substrate 105 along peel direction 125, in order to minimize the force applied to security feature 115. Depending on its shape, security feature 115 may present more than one peel direction.

[0028] FIGURES 2A-2C illustrate constructional aspects of a micro-optic security device (for example, security feature 115 in FIGURE 1) comprising part of a security document according to various embodiments of this disclosure. For consistency and convenience of cross-reference, part numbers common to more than one of FIGURES 2A-2C are numbered similarly.

[0029] Referring to the non-limiting example of FIGURE 2A, optical security device 200 comprises a plurality of focusing elements 205 (including, for example, focusing element 207), and an arrangement of first image icons 220 (including, for example, image icon 221). According to various embodiments, each focusing element of plurality of focusing elements 205 has a footprint, in which one or more image icons of arrangement of first image icons 220 is positioned. Collectively, the focusing elements of plurality of focusing elements 205, magnify portions of first image icons 220 to produce a synthetic magnification effect (also referred to as “synthetic image”) wherein the individually microscopic image icons are collectively magnified by the plurality of focusing elements 205 to produce an image which dynamically reacts (for example, by appearing to move, or change colors) in response to shifts in viewing angle. Given the small scale and tight manufacturing tolerances of the constituent structures of optical security device providing the moire magnification effect, many malicious actors are not able to produce counterfeit versions of optical security device 200.

[0030] First image icons 220 can comprise a plurality of sets of icons, wherein each set of icons occupies regions within focusing elements’ footprints associated with predetermined viewing angles. For example, image content predetermined to be visible when optical security device 200 is viewed “on axis” or from a perspective completely perpendicular to the planes of focusing elements 205 and first image icons 220 can be provided at or around the center of each focusing element’s footprint. Similarly, image content predetermined only to be visible from off-axis perspectives may be provided towards the periphery of each focusing element’s footprint. Accordingly, optical security device 200 is, in many cases, a trusted visual indicium of a security document’s (for example, security document 260) authenticity.

[0031] As noted elsewhere in this disclosure, security features according to this disclosure can include first image icons 220 that present at least one image (either static, dynamic or synthetic) which contains encoded information, but is only visible from off-axis viewpoints, thereby frustrating attempts to obtain high-resolution images of the encoded information with widely-available on-axis imaging equipment, such as flatbed scanners. In such embodiments, icons of first image icons 220 associated with the off-axis encoded image can be presented at peripheral locations within the footprints of focusing elements projecting such icons.

[0032] The present disclosure encompasses a variety of construction techniques for forming the image icon layer. First image icons 220 can, in some embodiments, be directionally cured image icons formed by through-the-lens curing of uncured icon material, thereby ensuring that the range of viewing angles at which first image icons 220 project an image does not include the head-on, or top-dead-center viewing angles which flatbed scanners and other commercial imaging apparatus utilize to obtain image data of substantially two-dimensional objects.

[0033] In some embodiments according to this disclosure, in addition to first image icons 220, the icon layer of the device includes a second icon layer, which can contain icons disposed at locations within the footprints of the focusing elements associated with on-axis, or head-on views. In some embodiments, such second image icons are formed using the same through-the-lens curing approaches used to generate first image icons 220. In such embodiments, the curing light source is moved between curing first image icons 220 and the second image icons, resulting in image icons that are intermingled among each other and at a substantially common distance away from array of focusing elements 205.

[0034] However, other configurations for realizing a micro-optic device with both directionally cured first image icons 220 and second image icons without also forming second image icons through directional curing of uncured radiation-curable light through focusing elements 205 are possible and within the contemplated scope of this disclosure. That is, in some embodiments, directionally cured first image icons 220 do not have to be perfectly coplanar with one another.

[0035] Referring to the illustrative examples of FIGURES 2B and 2C, security device 200 can also comprise a second strata in which second image icons are disposed. That is, in some embodiments, directionally cured first image icons 220 and a second set of image icons (which, can, but do not have to be, visible from on-axis viewing angles). Accordingly, additional optical effects can be realized by positioning the first and second image icons relative to each other such that directionally cured first image icons 220 occlude part of second image icons. Alternatively, additional optical effects can be realized by positioning the first and second image icons relatively to each other such that the second image icons, or retaining structures for the second image icons partially occlude directionally cured first image icons, thereby creating a “reward image” such as described in U.S. Patent Publication No. 2020 / 0384790.

[0036] FIGURE 2A illustrates an example embodiment in which a second icon layer 299 is formed closer to optical spacer 210, and which, if desired, can be configured to partially occlude directionally cured first image icons 220. FIGURE 2B illustrates an example embodiment in which directionally cured first image icons 220 are formed closer to optical spacer, and which, if desired, can be configured to partially occlude second icon layer 299.

[0037] In some embodiments, second icon layer 299 can also be formed by directionally curing uncured pigmented radiation curable-material, and then filling the interstitial spaces between icons to create a smooth surface upon which either directionally cured first image icons 220 can be formed, or second substrate 230 can be affixed. In some embodiments, second icon layer can be formed by first creating retaining structures (for example, by cast-curing a thin layer of (typically clear) radiation-curable material), and then filling the interstices of the retaining structures with pigmented material.

[0038] According to certain embodiments, plurality of focusing elements 205 comprises a planar array of micro-optic focusing elements. In some embodiments, the focusing elements of plurality of focusing elements 205 comprise micro-optic refractive focusing elements (for example, plano-convex or GRIN lenses). Refractive focusing elements of plurality of focusing elements 205 are, in some embodiments, produced from light cured resins with indices of refraction ranging from 1.35 to 1.7, and have diametersranging from 5 pm to 200pm. In various embodiments, the focusing elements of plurality of focusing elements 205 comprise reflective focusing elements (for example, very small concave mirrors), with diameters ranging from 5pm to 50pm. While in this illustrative example, the focusing elements of plurality of focusing elements 205 are shown as comprising circular plano-convex lenses, other refractive lens geometries, for example, lenticular lenses, are possible and within the contemplated scope of this disclosure.

[0039] As shown in the illustrative example of FIGURE 2, arrangement of first image icons 220 comprises a set of image icons (including image icon 221), positioned at predetermined locations within the footprints of the focusing elements of plurality of focusing elements 205. According to various embodiments, the individual image icons of arrangement of first image icons 220 comprise regions of light cured material associated with the focal path of structured light (for example, collimated UV light) passing through plurality of focusing elements 205 from a projection point associated with one or more predetermined ranges of viewing angles. In some embodiments, the individual image icons of arrangement of first image icons 220 are not provided within a structured image icon layer. As used in this disclosure, the term “structured image layer” encompasses a layer of material (for example, a light-curable resin) which has been embossed, or otherwise formed to comprise structures (for example, recesses, posts, grooves, or mesas) for positioning and retaining image icon material. According to various embodiments, the individual image icons of arrangement of first image icons 220 are provided within a structured image layer, the structured image layer comprising one or more of voids, mesas, or posts, which act as retaining structures to hold micro- and nano-scale volumes of colored material.

[0040] As shown in the illustrative example of FIGURE 2, in certain embodiments, optical security device 200 includes an optical spacer 210. According to various embodiments, optical spacer 210 comprises a film of substantially transparent material (for example, polyethylene terephthalate (“PET”) or Biaxially- Oriented Polypropylene (“BOPP”)) which operates to position image icons of arrangement of first image icons 220 in or around the focal plane of focusing elements of plurality of focusing elements 205. In certain embodiments according to this disclosure, optical spacer 210 comprises a manufacturing substrate upon which one or more layers of light curable material can be applied, to form one or more of arrangement of first image icons 220 or plurality of focusing elements 205.

[0041] According to various embodiments, optical security device 200 comprises one or more regions of light-cured protective material which occupy the spaces between the image icons of arrangement of first image icons 220. In some embodiments, the arrangement of first image icons 220 is first formed (for example, by selectively curing and removing liquid light-curable material on optical spacer 210), and then a layer of clear, light-curable material is applied to fill spaces between the image icons of arrangement of first image icons 220 and then flood-cured to create a protective layer, which protects the image icons from being moved from their positions within the footprints of focusing elements of plurality of focusing elements 205. In certain embodiments, the light-curable material used to form arrangement of first image icons 220 is a pigmented, ultraviolet (UV)-curable polymer.

[0042] In some embodiments, arrangement of first image icons 220 is affixed to a second substrate 230, which operates to protect and secure arrangement of first image icons 220 and provide an interface for attaching optical security device 200 to a substrate 250 as part of security document 260. In some embodiments, optical security device 200 is affixed to substrate 250 during the manufacture of substrate in a paper-making machine, such as a Fourdrinier machine. According to some embodiments, optical security device 200 is affixed to substrate 250 by a layer of adhesive between the arrangement of image icons and a top surface of substrate 250.

[0043] In certain embodiments according to this disclosure, optical security device 200 comprises a seal layer 240. According to certain embodiments, seal layer 240 comprises a thin (for example, a 2pm to 50pm thick layer) of substantially clear material which interfaces on a lower surface, with focusing elements of the plurality of focusing elements 205 and comprises an upper surface with less variation in curvature (for example, by being smooth, or by having a surface whose local undulations are of a larger radius of curvature than the focusing elements) than the plurality of focusing elements 205.

[0044] While FIGURE 2 provides one example of an optical security device according to various embodiments, the present disclosure is not so limited. Other optical security devices which provide controlled viewpoint validation are within the contemplated scope of this disclosure.

[0045] FIGURES 3A and 3B illustrate on-axis (FIGURE 3A) and off-axis (FIGURE 3B) views of an example security device 300 with controlled viewpoint validation according to various embodiments of this disclosure. For consistency and convenience of cross-reference, elements common to both FIGURES 3 A and 3B are numbered similarly.

[0046] Referring to the non-limiting example of FIGURE 3 A, a substantially on-axis view of a section of a micro-optic security device 300 according to certain embodiments of this disclosure is shown. As used in this disclosure, the expression “substantially on-axis view” encompasses a point from a camera or other lensed imaging apparatus that is directly on-axis for a portion of the subject matter shown in the view, but due to slight parallax in portions of the image away from the directly on-axis point, necessarily includes subject matter viewed from angles slightly deviating from perpendicular to the imaged object.

[0047] FIGURE 3A is based on an image obtained by a lens-based camera (for example, a smartphone camera or DSLR) with a field of view extending across two dimensions, rather than a lens-less line scanner of the type used in flatbed scanners.

[0048] Micro-optic security device 300 can embody the focusing layer-spacer layer-icon layer device architecture described with reference to FIGURE 2A. As described in greater detail herein, this architecture comprises at least two sets of image icons, which project two different sets of images when viewed across different viewing angles through a lensed camera (for example, a human eye or a smartphone camera).

[0049] As shown in FIGURE 3 A, the icon layer of security device 300 comprises a first set of image icons providing first image 305 with an encoded visual feature. In this example, the encoded visual feature of first image 305 is a quick-read (“QR”) code, which can be seen with the human eye and imaged with a digital camera, or other lensed imaging device from an off-axis viewing angle within a range of off-axisviewing angles. In some embodiments, encoded visual feature of first image 305 is a bar code. In some embodiments, encoded visual feature of first image 305 comprises a unique, serialized identifier which can be imaged by an off-axis lensed camera. For example, encoded visual feature of first image 305 can combine a multi-color image and textual or numeric information. In some embodiments, the image icons providing first image 305 are only partially visible within visible portions of the electromagnetic spectrum (for example, at wavelengths between 310 and 1100 nanometers).

[0050] Depending on the size of the range of off-axis viewing angles and the location of the lensed camera relative to security device 300, encoded visual feature of first image 305 may be visible to lensed cameras as a faint “ghost” image. This is due to the fact that, for most lensed viewing apparatus (notably, pairs of human eyes) some modicum of parallax and offset from perfect perpendicularity between is unavoidable. However, the “ghost” image of encoded visual feature of first image 305 in FIGURE 3 A cannot be seen with a flatbed scanner, or any other imaging device whose operation is premised on collecting image data along a single dimension from viewpoints fully perpendicular to security device 300.

[0051] As shown in FIGURE 3 A, the icon layer of security device 300 further comprises a second set of image icons, which when viewed through the layer of focusing elements, present a second set of images 310. In this example, second set of images 310 comprise a plurality of synthetically magnified dynamic motifs. Due to variances in a scale or repeat ratio between elements of the layer of focusing elements and icons of the layer of icon elements, images within second set of images 310 may appear to be above the plane of security device 300 (sometimes referred to as a “float effect”), or alternatively, beneath the plane of security device 300 (sometimes referred to as a ’’deep effect”). As used in this disclosure, the expression “scale or repeat ratio” encompasses the number of focusing elements within a specific unit of measurement (for example, a centimeter or inch) divided by the number of icon elements over the same unit of measurement. By modulating the scale or repeat ratio to values slightly above or below (i.e., between 0.98 to 1.02) 1.00, images of icon material projected through the array of focusing elements can be made to appear above or below the plane of security device 300.

[0052] In the explanatory example of FIGURES 3 A and 3B, second set of images 310 comprises two image motifs appearing at different depths relative to the plane of security device 300. A first motif comprises a set of lock-shaped icons 315 disposed in a repeating pattern and appearing beneath the plane of security device 300. Similarly, a second motif comprises a set of larger lock shaped icons 320 with alternating colors and periodic circular frames disposed in a repeating pattern and appearing above the plane of security device 300.

[0053] FIGURE 3B shows a second view of security device 300 obtained from a significantly off-axis (for example, 15-30 degrees away from perpendicular) perspective. As with FIGURE 3A, the view shown in the figure is one obtained via a lensed camera (such as the camera in a smartphone or a human eyeball). Specifically, FIGURE 3B illustrates the changes in appearance between images of the first image 305 and the second set of images 310 as a viewer’s perspective shifts from a substantially on-axis view to an off- axis view.

[0054] Referring to the illustrative example of FIGURE 3B, by moving the lensed camera from a substantially on-axis vantage point to a substantially off-axis vantage point, the contrast between first image 305 and background 325 is dramatically increased, as the focal points of the focusing elements move towards the peripheral footprint portions containing the icon material providing first image 305, thereby deepening the dark color of the first image 305 (in this case, the QR code) to a level where it can readily be imaged for analysis and authentication by a lensed off-axis camera.

[0055] FIGURES 4A and 4B illustrate aspects of methods for creating icon structures that support controlled viewpoint validation according to various aspects of this disclosure. For consistency and convenience of cross-reference, elements common to both FIGURES 4A and 4B are numbered similarly.

[0056] Referring to the illustrative example of FIGURE 4A, a section of a partially constructed security device 400 is shown in the figure. As with security device 200 in FIGURE 2, security device 400 embodies a multi-layer architecture comprising (at a minimum) a layer of focusing elements 405, the layer of focusing elements comprising a plurality of focusing elements (for example, refractive focusing element 407) disposed in a coplanar array, and an icon layer 410 comprising a plurality of image icons (for example, image icon 411) disposed in or adjacent to the focal plane of the focusing elements of the layer of focusing elements 405. Security device 400 can also include an optical spacer / substrate 415 disposed between layer of focusing elements 405 and icon layer 410. Optical spacer / substrate 415 can, in some embodiments, function as a manufacturing substrate, upon which layers of uncured polymer can be applied, embossed (for example, to form focusing elements or retaining structures for positioning and holding colored icon material), and subsequently cured. In some embodiments, security device 400 can be constructed using a purely top-down or bottom up (i.e., in an additive manner similar to 3-D printing) manufacturing process, thereby dispensing with the need for separate optical spacer / substrate 415.

[0057] As noted elsewhere in this disclosure, controlling the viewpoints of image content containing encoded authenticating information to be invisible to flatbed scanners and other apparatus which collect image data based on moving line scans from on-axis viewpoints can be achieved by positioning icons associated with encoded information towards the peripheries of the focusing elements’ footprints. In the illustrative example of FIGURE 4A, ensuring that icons (for example, image icon 411) occupy locations within the focusing elements’ footprints associated with off-axis viewing angles can be achieved by through-the-lens curing of icon material. According to certain embodiments, a layer of colored uncured radiation-curable polymer is applied to an underside of optical spacer / substrate 415, and then exposed to collimated, patterned curing light corresponding to the design of the first image. In some embodiments, the underside of optical spacer / substrate 415 includes retaining structures. The light source is positioned at a position corresponding to a predetermined range of viewing angle and causes the collimated, patterned light 420 to contact the focusing elements of array of focusing elements 405 at an angle. The focusing elements of array of focusing elements 405 focus the light, causing uncured radiation-curable polymer in peripheral regions of each focusing elements’ footprint to be cured, while leaving radiation-curable material in regions of the focusing elements’ footprints associated with on-axis and off-axis viewing angles outside of apredetermined range of viewing angles to remain uncured. The uncured material can be washed away, and the process repeated to create directionally cured image icons of different color or visible at different predetermined ranges of viewing angle. Further examples of through-the-lens curing of icon material may be found, for example, in U.S. Patent Publication Nos. 2022 / 0297463 and 2021 / 0053381, both of which are incorporated herein in their entireties.

[0058] FIGURE 4B illustrates aspects of an alternative method for creating image icons that support controlled-viewpoint validation according to certain embodiments of this disclosure. In a first step, a pattern of image icons (for example, image icon 451) for the first image are printed on a substrate 450 (which can be a clear or opaque substrate) at a spacing corresponding to a desired repeat period. Subsequently, an optical spacer 415 is applied on top of printed substrate 415, and focusing elements can be applied on top of optical spacer 415. Depending on the application (for example, whether the design goals specify that the encoded information not be visible on-axis, or visible at specific angles), and the nature of the focusing elements (for example, lenticular versus spherical lenses), the approach described with respect to FIGURE 4B can be a quick and efficient way of producing icon layers which support controlled viewpoint validation at speed and scale.

[0059] The examples shown with reference to FIGS. 3A-4B comprise an explanatory and illustrative subset of embodiments of micro-optic security devices implementing viewpoint-dependent authentication according to this disclosure. More specifically, certain embodiments according to this disclosure can create greater interplay between a selectively visible, machine -readable indicia of authenticity (for example, a QR code) and other image content projected by the system.

[0060] FIGS. 5A-5I illustrate examples of additional possible embodiments of micro-optic security devices which utilize selectively visible machine-readable indicia of authenticity. For consistency and convenience of cross reference, elements common to more than one of FIGS. 5A-5I are numbered similarly.

[0061] Referring to the illustrative example of FIG. 5A, two views of a micro-optic security device 501 according to this disclosure (for example, security device 300 in FIGS. 3A and 3B) are shown in the figure. In a first, top dead center view 503, machine-readable indicia of authenticity 502 (in this case, a QR code) is not visible. However, at a second, off-axis view 505, machine -readable indicia of authenticity 502 is visible. Micro-optic security device 501 operates similarly to security device 300 in FIGS. 3A and 3B in that the machine-readable indicia of authenticity 502 is not visible at viewing angles of used by flatbed scanners and other imaging tools but is visible at angles used by smartphones and other lensed imaging devices. Machine-readable indicia of authenticity 502 can extend its functionality as trustworthy evidence of its own authenticity by embedding, in the QR code, a link to a web address specifying the viewing angles over which machine-readable indicia of authenticity 502 should be visible. As noted elsewhere herein, achieving angular control over the angles at which synthetically magnified images projected by micro-optic systems are visible presents a significant technical and manufacturing, and can be a reliable point of difference between authentic security devices and very good copies.

[0062] Additionally, in some embodiments, machine-readable indicia of authenticity 502 can be “fingerprinted” during manufacturing, such that elements of the icon layer, which when projected through the array of focusing elements, project machine-readable indicia of authenticity 502 can contain features unique (hence the term “fingerprinting”) to one specific security device, or a series of security devices. According to some embodiments, “fingerprinting” of unique features within machine-readable indicia of authenticity 502 can be performed by directional through-the-lens curing of pigmented uncured material in an unstructured icon layer, such as described by U.S. Patent Publication No. 2022 / 0297463 (“the ‘463 Publication”), the contents of which are incorporated by reference herein. Additionally or alternatively, the machine-readable indicia of authenticity 502 can be produced through a combination of a structured icon layer in combination with the through-the-lens curing techniques described by the ‘463 Publication.

[0063] FIG. 5B illustrates another example embodiment of micro-optic security device 501 according to this disclosure. Provided sufficient control over the angles at which machine-readable indicia of authenticity 502 is visible, in some embodiments, machine-readable indicia of authenticity 502 can be visible in a top dead center view 503, and invisible in one or more off-axis views 505. In certain embodiments, the ability of machine-readable indicia of authenticity 502 to operate as reliable evidence of the authenticity of micro-optic security device 501 may not be diminished by the fact that the indicia of authenticity 502 can be imaged with a flatbed scanner or other imaging apparatus whose operation is premised on a top dead center view 503. For example, where machine-readable indicia of authenticity 502 contains a fingerprint (i.e., a device, or device-series variation in machine-readable indicia of authenticity 502) or specifies the range of angles over which machine-readable indicia of authenticity 502 is visible, the fact that the QR code providing machine-readable indicia of authenticity 502 can be read in a top dead center view 503 may not pose a security risk. This is because malicious actors remain unable to achieve precise angular control over the range of angles at which machine-readable indicia of authenticity can be read. Further, the parameters of the fingerprinting of machine-readable indicia of authenticity 502, as a whole, likely cannot be derived from a single device.

[0064] FIG. 5C illustrates another example of a micro-optic security device 501 with a variably-visible machine-readable indicia of authenticity 502. Similar to the example device described in FIG. 5 A, in an off-axis view 505, machine -readable indicia of authenticity 502 is visible, and can be imaged by apparatus (for example, smartphone cameras) which can obtain images through a lensed camera, rather than a line scan from atop dead center view 503. However, in contrast to the embodiment described with reference to FIG. 5 A, instead of projecting a blank field when viewed at top dead center view 503, in this example, a second image 507 is projected. Similar to the devices described with reference to FIGS. 5A and 5B, machine-readable indicia of authenticity 502 can be a QR code or other recognized format containing a pointer (for example, a URL) to a data source from which the intended range of viewing angles for machine- readable indicia of authenticity can be viewed.

[0065] Similar to FIG. 5B, FIG. 5D discloses an “inverse embodiment” of the example device of FIG. 5C, wherein machine-readable indicia of authenticity 502 is visible across a range of viewing angles whichincludes top dead center view 503, and second image 507 is visible at a range of angles which includes at least one off-axis view 505. Again, where machine-readable indicia of authenticity 502 either contains fingerprint data (which cannot be derived at scale by malicious actors) or pointers to information regarding the angles of view at authentic machine-readable indicia of authenticity 502 is visible, then the security risks of the machine-readable indicia of authenticity being visible at top dead center view 503 can be significantly mitigated.

[0066] FIGS. 5E and 5F illustrate two example embodiments of a micro-optic security device 501 combining a variably-visible machine-readable indicia of authenticity 502 in conjunction with obscuring icon content 509. Referring to the illustrative example of FIG. 5E, in this example embodiment, micro-optic security device 501 comprises a machine-readable indicia of authenticity 502, which in this example, is a QR code (but other machine-readable features are possible and within the scope of this disclosure. In the example of FIG. 5E, machine-readable indicia of authenticity 520 is partially visible at a top dead center view 503, but to thwart copying of the QR code or other encoded information contained in the image projected by micro-optic device 501 when viewed at top dead center view 503, obscuring icon content 509 is also visible, and operates to make the code or other machine-readable components of machine-readable indicia of authenticity 502 unreadable. According to certain embodiments, the scale ratio of the image icons, which, when projected through the array of focusing elements, appear as obscuring icon content 509 can differ from that of the icons, which when magnified by the array of focusing elements, as appear as machine- readable indicia of authenticity 502, giving the appearance of obscuring icon content 509 “floating” over the machine-readable indicia of authenticity 509.

[0067] By contrast, when viewed from one or more off-axis views 505, machine-readable indicia of authenticity 502 becomes unobscured and clearly visible to both human eyes and cameras.

[0068] FIG. 5F illustrates an example of micro-optic device 501, as described in FIG. 5E, but “reversed,” so that machine -readable indicia of authenticity 502 is visible at top dead center view 503, and obscuring icon content 509 becomes visible at off-axis viewing angles, such as off-axis view 505.

[0069] While FIGS. 5E and 5F illustrate example embodiments of a micro-optic security device 501 uses additional icon material to create obscuring icon content 509, embodiments according to this disclosure are not so limited, and can include embodiments in which icon material is selectively subtracted, or more likely, not included in portions of the footprints of focusing elements, such that obscuring icon content 509 appears as “holes” or “dead spots” in the machine-readable indicia of authenticity 502. For example, and as shown in the illustrative example of FIG. 5G, at a top dead center view 503, obscuring icon content 509 can appear as blank spots or missing areas in machine-readable indicia of authenticity 502. Similarly, in the “reverse” embodiment shown in FIG. 5H, obscuring icon content 509 is projected in off-axis view 505.

[0070] As skilled artisans and others will appreciate, the functionality of QR-codes and other machine- readable indicia which can be read with commonly available digital cameras (for example, mobile phone cameras) can depend significantly on the contrast of the encoded datum and the background against which it appears. A familiar example of this phenomenon is the way in which bar and QR codes (for example,paperless tickets and boarding passed) shown on a smartphone display often do not scan well unless the brightness of the display is turned up significantly beyond what is necessary for human eyes (which are typically more sensitive to contrast) to comfortably see.

[0071] FIG. 51 illustrates examples of a micro-optic security device 501 with a viewpoint dependent machine-readable indicia of authenticity 502, whose machine-readability at viewing angles within a desired range of viewing angles (for example, top dead center view 503, or one or more off-axis views 505) is enhanced by constructing the icon layer such that a contrast frame 511 appears at viewing angles at which machine-readable indicia of authenticity 502 is intended to be visible. As shown in the figure, contrast frame 511 comprises a region within micro-optic security device 501 wherein at least portions of the footprints of the focusing elements associated with the viewing angles at which machine-readable indicia of authenticity 502 is visible. In embodiments where some or all of the icon layer is formed using through-the-lens curing of uncured icon material in an unstructured icon layer (for example, as described in U.S. Patent Publication No. 2022 / 0297463).

[0072] The principle of enhancing the counterfeit-resistance of a micro-optic security device (for example, micro-optic security device 501 in FIGS. 5A-5I by limiting the visibility of the indicia to off-axis angles (thereby frustrating imaging QR codes and the like with an on-axis imager, such as a flatbed scanner), and by encoding information about the visibility properties of the indicia, or other aspects of authentication can be further extended by spreading the projection of the machine-readable indicia of authenticity across more than one off-axis viewing angles.

[0073] FIGS. 6A and 6B illustrate aspects spreading the projection of a machine-readable indicia of authenticity, such as a QR code or other presentation of visual data which can be recognized and read by a machine according to this disclosure. For consistency and convenience of cross-reference, elements common to both figures are numbered similarly.

[0074] Referring to the explanatory example of FIG. 6A, a micro-optic security device 600 (for example, micro-optic security device 200 in FIG. 2A) is shown in the figure. A machine-readable indicia of authenticity 601 (for example, machine-readable indicia of authenticity 502 in FIG. 5A) is shown in the figure, as it appears to a viewer with stereoscopic vision. In this example, due to the scale ratio of the image icons defining machine-readable indicia of authenticity 601 and the focusing elements of micro-optic security device 600, machine -readable indicia of authenticity 601 appears to “float” above the plane of micro-optic security device 600. Other embodiments, with different scale ratios, wherein machine-readable indicia of authenticity 601 appears to be below (also referred to as a “deep” effect), or coplanar with, machine-readable indicia of authenticity 601 are possible and within the contemplated scope of this disclosure.

[0075] As shown in FIG. 6A, at a first viewing angle 603, only a first portion (for example, first portion 605), but the remaining portions (for example, second portion 607) of machine-readable indicia of authenticity 601 are not visible at first viewing angle 603. In the example of FIG. 6A, both first viewingangle 603 and second viewing angle 609 are off-axis angles. However, there is no requirement no portion of the machine-readable indicia of authenticity be visible at a top dead center view.

[0076] At a second range of viewing angles 609, which are at, or approaching, top dead center, no portion of machine -readable indicia of authenticity 601 is visible. At a third range of viewing angles 611, second portion 607 (but not first portion 605) of machine-readable indicia of authenticity 601 becomes visible. In some embodiments, machine -readable indicia of authenticity 601 can include fiducial marks, watermarks, reference lines, or some features by which an image of the first portion 605 and second portion 607 can be joined to reproduce machine-readable indicia of authenticity 601 in its entirety.

[0077] FIG. 6B illustrates a further example of spreading the image of a machine-readable indicia of authenticity across two or more view angles according to this disclosure. In the figure, a micro-optic security device 600 according to this disclosure is shown in the figure. The icon layer of micro-optic security device 600 comprises icons which, collectively, project a machine -readable indicia of authenticity 601 across a set of viewing angles. As shown in the figure, machine-readable indicia of authenticity 601 is not entirely visible from any single vantage point or single range of viewing angles. Instead, machine -readable indicia of authenticity 601 is viewable in four separate parts (numbered i.-iv.) across four separate ranges of viewing angles, wherein the ranges of viewing angles include one or more off-axis views and can include a top dead center view. As noted with reference to FIG. 6A, the separate parts of machine-readable indicia of authenticity 601 can include fiducial marks, lines, or other embedded reference points to facilitate reconstruction of a full view of machine-readable indicia of authenticity 601.

[0078] It should be noted that the features described with reference to the examples of FIGS. 5A-6B are intended to be illustrative of, rather than limitative of the scope of this disclosure. Many of the features described with reference to FIGS. 5A-6B can be modified or provided in combination with each other. For example, contrast frame 511 described in FIG. 51 can be provided in embodiments in which the machine- readable indicia of authenticity is provided in pieces across multiple viewing angles.

[0079] FIGURE 7 illustrates operations of an example method 700 for authenticating a security feature with encoded features (for example, first image 305 in FIGURES 3A and 3B) according to various embodiments of this disclosure. The operations described with reference to FIGURE 7 can be performed at one or more suitably configured apparatus comprising a memory, a display, a processor, and a lensed camera which can obtain image data from a plurality of viewpoints (for example, a smartphone or tablet computing device). The operations of method 700 can also be performed in a distributed computing architecture, wherein part of the method, for example, obtaining image data is performed at a first computing device (for example, a smartphone) and other parts of the described method, for example, performing authentication, may be performed at a second computing device (for example, a cloud or physical server) connected over a network to the first device.

[0080] Referring to the illustrative example of FIGURE 7, at operation 705, a smartphone, tablet or other electronic device comprising a display, a processor, a lensed camera which can obtain image data from a plurality of viewpoints and a memory containing instructions, that, when executed, cause theapparatus to perform the operations of method 700, obtains image data (for example, an image of security device 300 in FIGURES 3A and 3B) of a security device that projects an image (for example first image 305 in FIGURE 3A) with encoded data for controlled viewpoint validation. Operation 705 can, in some embodiments, comprise taking a picture with the device’s onboard camera from an off-axis viewpoint at which the icons are generally invisible to flatbed scanners and other machines premised on-axis, point or line scanning. According to some embodiments, at operation 705, the image is obtained across a plurality of viewpoints, such as described with reference to FIGS. 6A and 6B. According to some embodiments, the security feature is, to some degree, machine-invisible in the sense that, at a minimum, the entirety of the indicia of authenticity provided by the security feature cannot be obtained from a single, top-dead center image of the security feature. As discussed herein, such machine-invisibility can be achieved by making the security feature only visible at off-axis views, such as described with reference to FIGS. 3 A and 3B of this disclosure. In some embodiments, machine-invisibility can be attained by providing an obscuring image at a top-dead center view, such as described with reference to FIG. 5E. In some embodiments, machineinvisibility can be attained by presenting the indicia of authenticity in pieces across multiple ranges of viewing angles, including some off-axis viewing angles, such as described with reference to FIGS. 6A and 6B. In some embodiments, machine-invisibility can be attained by making the indicia visible at top-dead center, but also having an off-axis component of the indicia of authenticity, such as a defined range of viewing angles over which the machine-readable indicia of authenticity can be seen.

[0081] At operation 710, a processor (either at the device which captured the image at operation 705, or a processor at a device connected via a network to same) performs an image recognition procedure on the obtained image data to recognize and decode authentication data provided in the image. According to certain embodiments, operation 710 can be performed utilizing code scanning software native to the operating system of a device (for example, embedded QR recognition software in iOS, or high-capacity color barcode (“HCCP”) recognition software embedded in Microsoft operating systems). As used in this disclosure, the expression “authentication data” comprises an alphanumeric string containing serialization numbers, embedded hashes, or other information from which a manufacturer or other legitimate actor can make a determination of the document’s authenticity or determine that the encoded data belongs to a compromised original. According to certain embodiments, operation 710 can include reassembling a view of the machine-invisible security feature from a plurality of images taken at different viewing angles.

[0082] At operation 715, a processor (either native to the device which captured the image data at operation 705, or at a device connected via a network to same) performs an authentication based on the authentication data obtained at operation 710. According to some embodiments, performing the authentication comprises assessing the alphanumeric string obtained at operation 710 according to closely held criteria maintained by the issuing body or other legitimate actor. Performing authentication can include, without limitation, hashing a portion of the alphanumeric string, obtaining a sum of one or more portions of the alphanumeric string, or comparing the alphanumeric string against a stored set of alphanumeric strings of legitimate security features. Based on the assessment according to closely heldcriteria, the device performing operation 715 obtains an authentication result (for example, a determination that the authentication data is, valid, not valid, or suspiciously duplicative of other alphanumeric strings for which authentication has been performed. At operation 720, an authentication result is displayed to a user. The result can be based on the authentication obtained at operation 715.

[0083] FIGURE 8 illustrates operations of an example method 800 of making a security device (for example, security device 200 in FIGURE 2 or 300 in FIGURES 3A and 3B) according to various embodiments of this disclosure.

[0084] Referring to the non-limiting example of FIGURE 8, at operation 805, an array of focusing elements is provided. Each focusing element of the array of focusing elements has a footprint. In some embodiments, the array of focusing elements can be an array of one or more of: spherical lenses (both refractive and / or reflective), lenticular lenses (both refractive and / or reflective), Fresnel and GRIN lenses. The array of focusing elements can be formed by cast-curing radiation material on an optical spacer / substrate layer. Alternatively, the array of focusing elements can be formed by transferring previously manufactured focusing elements onto the optical spacer / substrate layer.

[0085] At operation 810, a first set of image icons is provided, the first set of icons occupy a first subset of locations within footprints of the array of image elements. When viewed through the focusing elements across a first range of viewing angles (which does not include on-axis views), the first set of image icons project a first image, which contains machine-readable encoded information. When the security device is viewed on-axis, the first image is, if not fully invisible, then sufficiently faint as to not be detectable by on- axis imaging apparatus such as drum scanners, flatbed scanners, overhead scanners, microfilm scanners and slide scanners.

[0086] In some embodiments, the first array of image icons can be formed via through-the-lens curing (for example, as described with reference to FIGURE 4A of this disclosure). In some embodiments, the first array of image icons can be formed via laminating a pre-printed layer to the optical spacer (for example, as described with reference to FIGURE 4B of this disclosure). In some embodiments, the first array of image icons can be formed by selectively inking and selectively curing zones within a set of retaining structures. In some embodiments, the first image can be a synthetic image, which appears to float above, or be submerged beneath the plane of the security feature.

[0087] At operation 815, a second set of image icons (for example, the icons providing second set of images 310 in FIGURES 3 A and 3B) providing a second image is provided on the same side of an optical spacer / substrate as the first set of image icons. When viewed through the array of focusing elements, the second image provided by the second set of image icons is visible at on-axis viewing angles. In some embodiments, the second set of image icons can be provided by any suitable manufacturing technique, including through-the-lens curing of light-curable material, printing, and flood curing a wash coat of light curable material applied to a retaining structure after formation of the first array of image icons.

[0088] Examples of micro-optic security devices according to this disclosure include micro-optic security devices comprising an array of focusing elements, wherein each focusing element of the array offocusing element has a footprint, a first set of image icons, wherein image icons of the first set of image icons occupy a first subset of locations within footprints of the array of focusing elements, and a second set of image icons, wherein the second set of image icons comprise regions of directionally cured light curable material which occupy a second subset of locations within footprints of the array of focusing elements, the second set of image icons projecting a second image, wherein, when viewed through the array of focusing elements across a first predetermined range of viewing angles, the first set of image icons projects a first image, and wherein the first image is not detectable by an on-axis imaging apparatus.

[0089] Examples of micro-optic security devices according to this disclosure include micro-optic security devices wherein at least one of the first image or second image is a synthetic image.

[0090] Examples of micro-optic security devices according to this disclosure include micro-optic security devices wherein the first image is not detectable by an on-axis imaging apparatus from a group comprising: drum scanners, flatbed scanners, overhead scanners, on-axis barcode scanners, microfilm scanners and slide scanners.

[0091] Examples of micro-optic security devices according to this disclosure include micro-optic security devices wherein the first image comprises a one -dimensional barcode.

[0092] Examples of micro-optic security devices according to this disclosure include micro-optic security devices wherein the first image comprises at least one of a QR code, an HCCB code or a matrix barcode.

[0093] Examples of micro-optic security devices according to this disclosure include micro-optic security devices wherein the first predetermined range of viewing angles does not include an angle normal to the array of focusing elements.

[0094] Examples of micro-optic security devices according to this disclosure include micro-optic security devices wherein the array of focusing elements comprise an array of one or more of: spherical lenses, lenticular lenses, or sealed lenses.

[0095] Examples of micro-optic security devices according to this disclosure include micro-optic security devices wherein the first image is detectable by off-axis imaging apparatus.

[0096] Examples of micro-optic security devices according to this disclosure include micro-optic security devices wherein the first image is detectable by an off-axis imaging apparatus from a group comprising: three-dimensional scanners, extended reality headsets, and smartphone cameras.

[0097] Examples of micro-optic security devices according to this disclosure include micro-optic security devices wherein the first image comprises a serialized identification code or other unique image.

[0098] Examples of micro-optic security devices according to this disclosure include micro-optic security devices comprising a plurality of sets of image icons, wherein one or more of the plurality of sets of image icons is not detectable by an on-axis imaging apparatus, and wherein one or more of the plurality of sets of image icons is detectable by an on-axis imaging apparatus, wherein each of the one or more of the plurality of sets of image icons that is not detectable by an on-axis imaging apparatus has a distinct predetermined range of viewing angles, and wherein each of the one or more of the plurality of sets of imageicons that is detectable by an on-axis imaging apparatus has a distinct pre-determined range of viewing angles.

[0099] Examples of micro-optic security devices according to this disclosure include micro-optic security devices comprising a third set of image icons, wherein the third set of image icons comprise regions of directionally cured light curable material which occupy a third subset of locations within footprints of the array of focusing elements, wherein, when viewed through the array of focusing elements across a third range of viewing angles, the third set of image icons projects a third image, and wherein the third image is not detectable by an on-axis imaging apparatus.

[0100] Examples of methods of producing micro-optic security devices according to this disclosure include methods comprising providing an array of focusing elements, wherein each focusing element of the array of focusing elements has a footprint, providing a first set of image icons, wherein image icons of the first set of image icons occupy a first subset of locations within footprints of the array of focusing elements, and providing a second set of image icons, wherein the second set of image icons comprise regions of directionally cured light curable material which occupy a second subset of locations within footprints of the array of focusing elements, the second set of image icons projecting a second image, and wherein, when viewed through the array of focusing elements across a predetermined first range of viewing angles, the first set of image icons projects a first image, and wherein the first image is not detectable by an on-axis imaging apparatus.

[0101] Examples of methods of producing micro-optic security devices according to this disclosure include methods wherein at least one of the first image or the second image is a synthetic image.

[0102] Examples of methods of producing micro-optic security devices according to this disclosure include methods wherein the first image is not detectable by an on-axis imaging apparatus from a group comprising: drum scanners, flatbed scanners, on-axis barcode scanners, overhead scanners, microfilm scanners and slide scanners.

[0103] Examples of methods of producing micro-optic security devices according to this disclosure include methods wherein the first image is a one-dimensional barcode.

[0104] Examples of methods of producing micro-optic security devices according to this disclosure include methods wherein the first image comprises at least one of: a QR code, an HCCB code, or a matrix barcode.

[0105] Examples of methods of producing micro-optic security devices according to this disclosure include methods wherein the first image comprises a serialized identification code or other unique image.

[0106] Examples of methods of producing micro-optic security devices according to this disclosure include methods wherein the array of focusing elements comprise an array of one or more of: spherical lenses, lenticular lenses, or sealed lenses.

[0107] Examples of methods of producing micro-optic security devices according to this disclosure include methods wherein the first image is detectable by off-axis imaging apparatus.

[0108] Examples of methods of producing micro-optic security devices according to this disclosure include methods wherein the first image is detectable by an off-axis imaging apparatus from a group comprising: three-dimensional scanners, extended reality headsets, and smartphone cameras.

[0109] Although the present disclosure has been described with various embodiments, various changes and modifications may be suggested to one skilled in the art. It is intended that the present disclosure encompass such changes and modifications as falling within the scope of the claims.

[0110] The present disclosure should not be read as implying that any particular element, step, or function is an essential element, step, or function that must be included in the scope of the claims. Moreover, the claims are not intended to invoke 35 U.S.C. § 112(f) unless the exact words “means for” are followed by a participle.

Claims

WHAT IS CLAIMED IS:

1. A micro-optic device (300), comprising: an array of focusing elements (205), wherein each focusing element of the array of focusing elements has a footprint; a first set of image icons (220), wherein image icons of the first set of image icons comprise regions of directionally cured light curable material which occupy a first subset of locations within footprints (411) of the array of focusing elements; and a second set of image icons (299), wherein the second set of image icons occupy a second subset of locations within footprints of the array of focusing elements, the second set of image icons projecting a second image (320), wherein, when viewed through the array of focusing elements across a first predetermined range of viewing angles, the first set of image icons projects a first image (305), and wherein the first image is not detectable by an on-axis imaging apparatus.

2. The micro-optic device of claim 1, wherein at least one of the first image or the second image is a synthetic image.

3. The micro-optic device of claim 1, wherein the first image is not detectable by an on-axis imaging apparatus from a group comprising: drum scanners, flatbed scanners, overhead scanners, on-axis barcode scanners, microfilm scanners, and slide scanners.

4. The micro-optic device of claim 1, wherein the first image comprises a one-dimensional barcode.

5. The micro-optic device of claim 1, wherein the first image comprises at least one of a QR code, an HCCB code, or a matrix barcode.

6. The micro-optic device of claim 1, wherein the first predetermined range of viewing angles does not include an angle normal to the array of focusing elements.

7. The micro-optic device of claim 1, wherein the array of focusing elements comprise an array of one or more of spherical lenses, lenticular lenses, or sealed lenses.

8. The micro-optic device of claim 1, wherein the first image is detectable by an off-axis imaging apparatus.

9. The micro-optic device of claim 8, wherein the first image is detectable by an off-axis imaging apparatus from a group comprising: three-dimensional scanners, extended reality headsets, and smartphone cameras.

10. The micro-optic device of claim 1, wherein the first image comprises a serialized identification code or other unique image.

11. The micro-optic device of claim 1, further comprising a third set of image icons, wherein the third set of image icons comprise regions of directionally cured light curable material which occupy a third subset of locations within footprints of the array of focusing elements, wherein, when viewed through the array of focusing elements across a third range of viewing angles, the third set of image icons projects a third image, and wherein the third image is not detectable by an on-axis imaging apparatus.

12. A method of creating a micro-optic device, comprising: providing an array of focusing elements (805), wherein each focusing element of the array of focusing elements has a footprint; providing a first set of image icons (810), wherein image icons of the first set of image icons comprise regions of directionally cured light curable material which occupy a first subset of locations within footprints of the array of focusing elements; and providing a second set of image icons (815), wherein the second set of image icons occupy a second subset of locations within footprints of the array of focusing elements, the second set of image icons projecting a second image, wherein, when viewed through the array of focusing elements across a predetermined first range of viewing angles, the first set of image icons projects a first image, and wherein the first image is not detectable by an on-axis imaging apparatus.

13. The method of claim 12, wherein at least one of the first image or the second image is a synthetic image.

14. The method of claim 12, wherein the first image is not detectable by an on-axis imaging apparatus from a group comprising: drum scanners, flatbed scanners, on-axis barcode scanners, overhead scanners, microfilm scanners, and slide scanners.

15. The method of claim 12, wherein the first image is a one-dimensional barcode.

16. The method of claim 12, wherein the first image comprises at least one of a QR code, an HCCB code, or a matrix barcode.

17. The method of claim 12, wherein the first image comprises a serialized identification code or other unique image.

18. The method of claim 12, wherein the array of focusing elements comprise an array of one or more of spherical lenses, lenticular lenses, or sealed lenses.

19. The method of claim 12, wherein the first image is detectable by an off-axis imaging apparatus.

20. The method of claim 19, wherein the first image is detectable by an off-axis imaging apparatus from a group comprising: three-dimensional scanners, extended reality headsets, and smartphone cameras.

Images