Micro-optical security device having multi-phase icon structure

Abstract

The optical security device (100) includes a light collection element array (105) with light collection elements spaced apart at a first pitch along a first repeat axis (415), each light collection element of the light collection element array being associated with a focal footprint at a first focal depth. The optical security device further includes an icon layer (120) positioned at the first focal depth relative to the light collection element array, the icon layer including an array of hybrid image icons. Each of the hybrid image icons (410) includes a first component (410a) associated with a first exit image projected by the optical security device and a second component (410b) associated with a second exit image projected by the optical security device.

Description

[Technical field]

[0001] The present disclosure relates generally to anti-counterfeiting of secure or high-value documents such as banknotes, passports, tickets, etc. More specifically, the present disclosure relates to a micro-optical security device having a multi-phase icon structure. [Background technology]

[0002] Micro-optical security devices, i.e., devices comprising an array of microscale light-collecting elements and an arrangement of image icons (e.g., sub-microscale regions of colored material) in the focal plane of the light-collecting elements that cooperate to provide one or more distinctive visual effects (e.g., emergent or "synthetic" images having a three-dimensional appearance), have proven generally effective in providing reliable visual indicia of the authenticity of important documents such as currency notes and passports.

[0003] The performance and effectiveness of a micro-optical security device as a visual level indicia of a document's authenticity (i.e., an indicia that is detectable by the human eye, rather than by banknote equipment manufacturers' ("BEM") equipment or other specialized machinery) may depend, at least in part, on the extent to which the micro-optical security device provides visual effects that are visually appealing to a user, and on the extent to which the appearance of, and the visual effects provided by, the security device exceed the current capabilities of counterfeiters and malicious actors.

[0004] Micro-optical security devices that provide novel visual effects (i.e., visual effects never before seen) can be particularly effective in that their novelty not only increases the likelihood of attracting users (because users are more likely to notice features they have never seen before), but at the same time reduces the incidence of counterfeiting (because counterfeiters have not yet mastered the manufacturing and design techniques used to create the novel visual effects).

[0005] Thus, expanding the range of visual effects provided by micro-optical security devices remains a source of technical challenges and opportunities for improvement in the art. Summary of the Invention

[0006] The present disclosure provides a miniature optical security device having a multi-phase icon structure.

[0007] In a first embodiment, an optical security device includes a light collection element array with light collection elements spaced apart at a first pitch along a first repeat axis, each light collection element of the light collection element array being associated with a focal footprint at a first focal depth. The optical security device includes an icon layer disposed at the first focal depth relative to the light collection element array, the icon layer comprising an array of hybrid image icons. Each hybrid image icon includes a first component associated with a first emergent image projected by the optical security device and a second component associated with a second emergent image projected by the optical security device. The first components of the hybrid image icons are repeated along the first repeat axis such that the first components of the hybrid image icons occupy a first phase space within the focal footprints of the light collection elements of the light collection element array. The second component of the hybrid image icon is repeated along the first repeat axis such that the second component of the hybrid image icon occupies a second phase space within a focal footprint of a focusing element of the focusing element array.

[0008] In a second embodiment, a method of manufacturing an optical security device includes providing an array of focusing elements with focusing elements spaced apart at a first pitch along a first repeat axis, each focusing element of the focusing element array being associated with a focal footprint at a first focal depth. The method includes providing an icon layer disposed at the first focal depth for the array of focusing elements, the icon layer comprising an array of hybrid image icons. Each hybrid image icon includes a first component associated with a first emergent image projected by the optical security device and a second component associated with a second emergent image projected by the optical security device. The first components of the hybrid image icons are repeated along the first repeat axis such that the first components of the hybrid image icons occupy a first phase space within the focal footprints of the focusing elements of the focusing element array. The second component of the hybrid image icon is repeated along the first repeat axis such that the second component of the hybrid image icon occupies a second phase space within a focal footprint of a focusing element of the focusing element array.

[0009] Other technical features may be readily apparent to those skilled in the art from the following drawings, detailed description, and claims.

[0010] Before proceeding with the detailed description below, it may be advantageous to present 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," and their derivatives, mean an open-ended inclusion. The term "or" is inclusive, meaning and / or. The phrase "associated with," as well as words derived therefrom, have meanings including "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," and the like. The functionality associated with any particular controller may be centralized or distributed, whether local or remote. 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 that only one item in the list may be required. For example, "at least one of A, B, and C" includes any combination of A, B, C, A and B, A and C, B and C, and A, B, and C.

[0011] Definitions of other specific words and phrases are provided throughout this patent document, and those of skill in the art should understand that in many, if not most, cases such definitions apply to prior and future uses of the words and phrases so defined.

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

[0013] [Figure 1] FIG. 1 illustrates an example of a micro-optical system in accordance with certain embodiments of the present disclosure. [Diagram 2] FIG. 2 is an exploded perspective view showing a micro-optical cell within a micro-optical security device according to certain embodiments of the present disclosure. [Figure 3A] FIG. 3A illustrates aspects of focal footprints of focusing elements according to various embodiments of the present disclosure. [Figure 3B] FIG. 3B is a diagram illustrating aspects of the focal footprint of a focusing element according to various embodiments of the present disclosure. [Figure 3C] FIG. 3C illustrates aspects of focal footprints of focusing elements according to various embodiments of the present disclosure. [Figure 4] FIG. 4 is a diagram illustrating an example of a hybrid icon for a focal footprint in accordance with certain embodiments of the present disclosure. [Diagram 5] FIG. 5 illustrates an example of an icon layer with a hybrid icon according to various embodiments of the present disclosure relative to the footprint of a concentrating element of a concentrating element array. [Figure 6] FIG. 6 is a diagram illustrating an example of a topological space between components of a hybrid pictorial icon according to various embodiments of the present disclosure. [Figure 7] FIG. 7 illustrates an example of a focal footprint and a hybrid image icon with three components according to various embodiments of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] 1-7 described below and the various embodiments used to illustrate the principles of the present disclosure in this patent document are for illustrative purposes only and should not be construed as limiting the scope of the present disclosure in any way.

[0015] FIG. 1 illustrates an example of a micro-optical system 100 in accordance with certain embodiments of the present disclosure. Referring to the non-limiting example of FIG. 1, the micro-optical system 100 at a basic level comprises a planar array of focusing elements 105 (e.g., including focusing element 107) and an image icon array 120 (e.g., including image icon 121). In the example shown in FIG. 1, the focusing elements of the planar array of focusing elements are spherical lenses. However, other types of focusing elements are possible and are within the contemplation of the present disclosure. Examples of focusing elements suitable for use in a micro-optical system according to the present disclosure include, but are not limited to, aspheric lenses, Fresnel lenses, reflective lenses, lenticular lenses, and encapsulated lenticular lenses. According to various embodiments, each focusing element of the planar array of focusing elements 105 has a focal footprint in which one or more image icons of the image icon array 120 are located. In certain embodiments, the location of the image icons in the image icon array 120 within the respective focal footprint of each focusing element corresponds to the space between the holding structures in the image icon layer.

[0016] The term "focal footprint" as used in this disclosure encompasses an area in or adjacent to a focal plane of a focusing element where the focusing element may focus light within one or more predefined criteria (e.g., brightness and sharpness of focus). In some embodiments, the focal footprint of a focusing element may be coextensive with the base of the focusing element. Alternatively, the focal footprint of a focusing element may differ in one or more of the shape and area of ​​the base of the focusing element. As an illustrative example, a focusing element (e.g., a spherical lens or reflector) with a circular base profile may have a hexagonal focal footprint.

[0017] According to some embodiments, the ratio of the resolution of the planar array of focusing elements 105 (e.g., the number of focusing elements provided within a designated area, such as a 1 mm×1 mm box) to the resolution of the image icon array 120 (e.g., the number of focusing elements provided within a designated area) is equal to or greater than 1. As a non-limiting example, each image icon in the image icon array 120 can fall within the focal footprint of multiple focusing elements. As a further non-limiting example, an image icon may not be present within the focal footprint of all focusing elements within a designated area. Furthermore, in some embodiments according to the present disclosure, the ratio of the resolution of the planar array of focusing elements 105 to the resolution of the image icon array 120 may have a value less than 1.

[0018] According to certain embodiments, the plurality of focusing elements 105 comprises a planar array of micro-optical focusing elements. In some embodiments, the focusing elements of the planar array of focusing elements 105 comprise micro-optical refractive focusing elements (e.g., plano-convex lenses or GRIN lenses) having lens surfaces that provide a curved interface between regions of different refractive index (e.g., polymer lens material and air). The refractive focusing elements of the planar array of focusing elements 105 are fabricated from a photocurable resin having a refractive index in the range of 1.35 to 1.7 in some embodiments and have a diameter in the range of 5 μm to 200 μm. In various embodiments, the focusing elements of the planar array of focusing elements 105 comprise reflective focusing elements (e.g., very small concave mirrors) having a diameter in the range of 5 μm to 200 μm. In this illustrative example, the focusing elements of the planar array of focusing elements 105 are illustrated as comprising circular plano-convex lenses, although other refractive lens shapes, such as lenticular lenses, may be used and are within the contemplation of the present disclosure.

[0019] According to various embodiments, the focusing elements of the planar array of focusing elements 105 are arranged at regular intervals (sometimes referred to as "pitch" or "lens pitch") along at least one repeat axis. In the case of a lenticular array of focusing elements, the focusing elements are arranged along a single repeat axis. However, in the case of spherical or other focusing element shapes, the focusing elements of the planar array of focusing elements 105 may be repeated across two repeat axes. Furthermore, depending on the configuration of the focusing elements, the repeat axes may or may not be orthogonal to each other.

[0020] As illustrated in FIG. 1, the image icon array 120 includes a set of image icons (including image icon 121) arranged at predetermined locations within the focal footprint of the focusing elements of the planar array of focusing elements 105. According to various embodiments, the individual image icons of the image icon array 120 include regions of photocurable material that are within spaces defined by holding structures in a structured image icon layer. The term "structured image layer" as used in this disclosure encompasses a layer of material (e.g., photocurable resin) that is embossed or otherwise formed to include structures (e.g., recesses, posts, grooves, or mesas) for positioning and holding the image icon material. According to certain embodiments, the image icon array 120 is constructed to facilitate dynamic redesign and reconfiguration of the image icon structures of the micro-optical system 100. For example, the image icon array 120 is formed in some embodiments by selectively filling and curing the holding structures (e.g., square wells as shown in FIG. 1) with one or more colors of uncured pigment material, thereby forming color regions or zones within the image icon array 120. In this non-limiting example, different colors in image icon array 120 are represented by different fill patterns on the surface of the image icon closest to the focusing layers. For example, image icon 121 is illustrated as having the same color as the image icons in its row.

[0021] As described with reference to the examples shown in Figures 4-7 of this disclosure, in certain embodiments, the image icons in the image icon array 120 may be hybrid image icons. The term "hybrid image icon" as used in this disclosure encompasses an image icon that is subdivided into two or more components, each of which may occupy a different phase along a repeat axis shared between the light collection element and the icon structure.

[0022] As illustrated in FIG. 1, in certain embodiments, the micro-optical system 100 comprises an optical spacer 110. According to various embodiments, the optical spacer 110 comprises a film of a substantially transparent material that operates to position the graphical icons of the graphical icon array 120 in or around the focal plane of the focusing elements of the planar array of focusing elements 105. In certain embodiments according to the present disclosure, the optical spacer 110 comprises a fabrication substrate on which one or more layers of a photocurable material can be applied, embossed, and flood cured to form a holding structure that can then be filled with a cured pigmented photocurable material to produce the icon structure. In certain embodiments, the photocurable material used to form the graphical icon array 120 is a pigmented ultraviolet (UV) curable polymer.

[0023] In certain embodiments according to the present disclosure, the micro-optical system 100 comprises an encapsulation layer 140. According to certain embodiments, the encapsulation layer 140 comprises a thin layer of a substantially transparent material (e.g., a layer having a thickness of 2 μm to 50 μm), contacts the focusing elements of the planar array of focusing elements 105 at a lower surface of the encapsulation layer 140, and has an upper surface that has less variation in curvature than the planar array of focusing elements 105 (e.g., by having a surface that is smooth or has a larger radius of curvature of localized relief than the focusing elements).

[0024] As shown in the non-limiting example of FIG. 1, in certain embodiments, the micro-optical system 100 can be attached to a substrate 150, for example, by an adhesive layer 130, to form a security document 160. According to various embodiments, the substrate 150 can be a bill sheet or a polymer substrate. According to some embodiments, the substrate 150 is a thin flexible sheet of biaxially oriented polypropylene (BOPP), which is a polymer film. In various embodiments, the substrate 150 is a piece of synthetic paper material, such as TESLIN®. According to some embodiments, the substrate 150 is a piece of polymer card material, such as a polyethylene terephthalate (PET) blank of the type suitable for making credit cards and driver's licenses.

[0025] 2 illustrates an exploded top-down perspective view of a micro-optical cell 200 within a micro-optical security device (e.g., micro-optical system 100 of FIG. 1) in accordance with certain embodiments of the present disclosure. As used in this disclosure, the term "micro-optical cell" encompasses a three-dimensional portion of a micro-optical security device that corresponds to a single light collection element within a planar array of light collection elements (e.g., planar array of light collection elements 105 of FIG. 1).

[0026] Referring to the non-limiting example of FIG. 2, the micro-optical cell 200 is one of a plurality (in some embodiments, millions) of micro-optical cells that form a micro-optical security device (e.g., the micro-optical system 100 of FIG. 1). According to various embodiments, the micro-optical cell 200 includes a focusing element 207. In this illustrated example, the focusing element 207 is a refractive focusing element (in this case, a plano-convex lens) that is formed by applying a layer of photocurable material to an optical spacer layer 210 (e.g., a layer of transparent film material that also serves as a fabrication substrate), embossing the layer of photocurable material to define the shape of the focusing element 207, and in some embodiments embossing additional optical spacers 201 (sometimes referred to as "goo spacers") depending on the F# of the focusing element, and then curing the material with light (e.g., ultraviolet light) to cause one or more chemical curing reactions to produce a layer of photocurable material that is robust enough for use in a micro-optical security device.

[0027] According to various embodiments, the micro-optical cell 200 further comprises a portion 220 of a structured image icon layer (e.g., an image icon layer including the image icon array 120 of FIG. 1). Referring to the non-limiting example of FIG. 2, the portion 220 of the structured image icon layer comprises a plurality of retaining structures, each of which defines an isolated volume having a first depth. In various embodiments according to the present disclosure, the image icon layer including the portion 220 is constructed using a manufacturing technique similar to that of the light concentrating element 207, in which a layer of uncured photocurable material is applied to the side of the optical spacer layer 210 and embossed to form a plurality of retaining structures, and then exposed to a light source to activate a curing reaction in the material and produce a cured structured image icon layer.

[0028] As described elsewhere in this disclosure, dimensions along which the performance of a micro-optical security device can be measured include, but are not limited to, how visually appealing the device and the optical effects produced by the device are. If a micro-optical security device is reliably "eye-catching," then the absence of such a device, or irregularities in the device's appearance, are more likely to be noticed by a user. Aesthetics are appealing, and from an anti-counterfeiting perspective, appeal can be highly advantageous.

[0029] Experience has shown that the vividness and presence of multiple colors in the visual effects presented by micro-optical systems (e.g., emergent images, also referred to as "synthetic images") can attract people's attention. In many cases, micro-optical security devices are more likely to provide vivid-looking visual effects when the image icon has an appropriate thickness and is located within the focal plane of the light-collecting elements of the planar array of light-collecting elements. According to some embodiments, suitable image icon thicknesses include a range of thicknesses from 0.5 μm to 3.5 μm. In some embodiments, suitable image icon thicknesses include narrower ranges of thicknesses, such as, for example, 0.5 μm to 2.5 μm, or 1.5 μm to 1.8 μm. In some applications, suitable image icons have thicknesses greater than 3.5 μm or less than 0.5 μm. A "faint" or out-of-focus icon, including but not limited to, may cause the colors of the emergent image to appear washed out and image details to appear blurred.

[0030] Advantageously, certain embodiments according to the present disclosure include hybrid image icons that are located within the focal footprint of the focusing element, and have two or more independently phased components. In this way, certain embodiments according to the present disclosure achieve pleasing sharpness and color (because each component of the hybrid icon has sufficient depth to coincide with, or at least be close to, the focal point of the focusing element 207). At the same time, by subdividing each image icon into multiple components that occupy separate phase spaces, emergent images with complex (i.e., more than one at a time) and dynamic visual effects can be realized.

[0031] As one non-limiting example of how certain embodiments according to the present disclosure can expand the range of dynamic visual effects that can be provided by a micro-optical system that projects one or more emergent images of a portion of an icon layer, certain embodiments according to the present disclosure can present a "multiple rolling band" effect in which multiple bands of color are projected by either a lenticular or multi-directional array of light-gathering elements and appear to roll continuously through space. Additionally, some embodiments according to the present disclosure can modulate the speed of each band and the perceived height of the band relative to the plane of the optical security device. Previously, with a standalone icon structure, such rolling band effects have been limited to single-color bands that appear to shimmer or roll in space.

[0032] Figures 3A-3C (collectively "Figure 3") show an example of how a focusing element focuses light within a focal footprint, according to various embodiments of the present disclosure. For ease of cross-referencing, items common to two or more of Figures 3A-3C are similarly numbered.

[0033] Referring to the non-limiting example of FIG. 3, a side view (FIG. 3C), a bottom view (FIG. 3A), and a perspective view (FIG. 3B) of a refractive focusing element 301 disposed on a portion of an optical spacer 303 are shown. According to certain embodiments, the focusing element 301 is affixed to the optical spacer 303 and has a fixed relationship with respect to a surface of the optical spacer 303. In certain embodiments, the fixed relationship between the focusing element 301 and the surface of the optical spacer 303 is achieved by applying a layer of photocurable material to the optical spacer 303, embossing the layer of photocurable material to form a lens surface, and curing the material in situ. In some embodiments, the fixed relationship between the focusing element 301 and the surface of the optical spacer 303 is achieved by forming both the focusing element 301 and the optical spacer from a common layer of photocurable material and curing the formed layer to create an integrated focusing element-optical spacer combination.

[0034] The focusing element 301, according to some embodiments, is associated with a focal footprint 305 that is coextensive with the periphery of the focusing element 301. According to some embodiments, the focal footprint 305 is smaller than the periphery of the focusing element 301. In certain embodiments, the focal footprint 305 describes an area that is larger than the periphery of the focusing element 301.

[0035] As illustrated in FIG. 3, light is incident on the lens surface of the concentrator 301 at an angle (or range of angles) related to the viewing angle, which is denoted as Θ in FIG. c The lens action of the focusing element 301 focuses the incident light to an area 320 within the focal footprint 305.

[0036] 4 illustrates an example of a hybrid image icon 410 having a first component 410a and a second component 410b for a focal footprint 405 of a focusing element. According to various embodiments, the focal footprint 405 is the focal footprint of a circular focusing element. In some embodiments, the focal footprint 405 is a subdivision of the focal footprint of a lenticular lens.

[0037] In this illustrative example, the hybrid image icon 410 is part of a micro-optical security device (e.g., micro-optical system 100 of FIG. 1) that comprises a larger array of image icons (e.g., image icon array 120 of FIG. 1). Similarly, the focusing element that generates the focal footprint 405 is part of a larger array of focusing elements of the micro-optical security (e.g., planar array of focusing elements 105 of FIG. 1). Furthermore, the hybrid image icon 410 is part of an icon layer and is repeatedly arranged along at least a first repeat axis 415. Similarly, the focusing elements of the micro-optical security device are regularly repeated along the first repeat axis 415 according to the pitch of the focusing elements.

[0038] According to various embodiments, when a hybrid image icon of the micro-optical security device (e.g., hybrid image icon 410) is viewed through the focusing elements (or reflected by the focusing elements in the case of reflective focusing elements), the combined interaction of the focused light of each focusing element and the projected light from a portion of the footprint produces a composite image, such as described in U.S. Pat. No. 7,738,175 to Steenblik et al., which is incorporated by reference herein.

[0039] In certain embodiments, the hybrid image icon 410 is subdivided into two or more components, each occupying a separate phase space in the image icon layer. A micro-optical system according to certain embodiments of the present disclosure projects an emergent image due to the fact that the icon structure is arranged to repeat with a similar periodicity and along a similar repeat axis(es) as the focusing elements of the array of focusing elements. Furthermore, the appearance and dynamic behavior of the emergent image (e.g., how the emergent image changes in response to changes in the user's viewing angle) can be modulated by, without limitation, changing the relative periodicity (i.e., changing the phase) of the structures in the icon layer with respect to the pitch of the focusing elements. For example, a slight skew between the repeat axis of the focusing elements and the repeat axis of the icon structure can result in orthoparallactic movement of the emergent image, where a change in viewpoint along a first axis results in a change in the emergent image along a second axis that is orthogonal to the first axis. Other design variables of the icon structure that can be modulated to change the appearance of the visual effect produced by the system include, but are not limited to, changing the area of ​​the icon structure (which can change the darkness of the emergent image(s)).

[0040] Referring to the non-limiting example of Figure 4, the first components 410a and 410b of the hybrid image icon 410 occupy different phase spaces. The term "phase space" as used in this disclosure encompasses the phase of the repetition of the component of the hybrid image icon relative to the repetition period (i.e., pitch) of the focusing elements, and the phase and offset of the repetition of the component of the hybrid image icon relative to other components of the hybrid image icon. Thus, the phase space can be a function of the ratio between a given component of the hybrid image icon and the pitch of the focusing elements along a given repeat axis, and the offset between a given component of the hybrid image icon and other components of the hybrid image icon.

[0041] FIG. 5 illustrates an example of an icon layer including hybrid icons according to various embodiments of the present disclosure relative to the focal footprint of a focusing element of a focusing element array.

[0042] Referring to the non-limiting example of FIG. 5, focal footprints (including focal footprints 501a and 501b) of some focusing elements of a focusing element array (e.g., planar array of focusing elements 105 of FIG. 1) are illustrated. Additionally, the location of a hybrid image icon (e.g., hybrid image icon 410 of FIG. 4) of a larger array of image icons (e.g., image icon array 120 of FIG. 1) relative to the footprint of each focusing element is illustrated in FIG. 5. Additionally, the focal spot (e.g., focal spot 505) of each focusing element relative to its focal footprint is illustrated in FIG. 5. In the illustrative example of FIG. 5, the size of the focal spot relative to the focal footprint is exaggerated for ease of illustration. In certain embodiments according to the present disclosure, the focusing elements can generate focal spots on the order of 1 μm in diameter.

[0043] As mentioned elsewhere in this disclosure, the phase difference between the repetition of the focusing elements (and, by implication, their foci in the shared focal plane) along one or more repeat axes (e.g., the first repeat axis 510) and the repetition of the icon structure can give rise to an emergent image of the contents of the image icon layer projected by the system across a micro-optical array comprising thousands, or more typically millions, of cells.

[0044] Referring again to the illustrated example of FIG. 5, by utilizing hybrid image icons (e.g., hybrid image icon 515) in which each image icon includes two or more components, certain embodiments according to the present disclosure project emergent images that include two or more dynamic components. In this illustrated example, the hybrid image icon comprises a first component and a second component, and for a given viewing angle, the first component, the second component, or both the first and second components can fall within the focal point (e.g., focal point 505) of the focusing element. In this manner, certain embodiments according to the present disclosure can project multiple emergent images (i.e., emergent images associated with each component of the hybrid image icon) over the same angular space (i.e., range of viewing angles) while the micro-optical device is tilted. As one non-limiting example of how the range of effects provided by a micro-optical security device can be expanded by projecting multiple emergent images in the same space in accordance with some embodiments of the present disclosure, a device according to the present disclosure can project multiple "rolling bars" or "shimmer" effects at once, even in devices that utilize lenticular focusing elements. Such composite "shimmer" effects are believed to be previously unknown in the art.

[0045] FIG. 6 illustrates an example of a topological space between components of a hybrid pictorial icon according to various embodiments of the present disclosure.

[0046] With reference to the illustrated example in FIG. 6, a first focal footprint 601a and a second focal footprint 601b are illustrated. Furthermore, the first focal footprint 601a covers an area in the array of image icons (e.g., image icon array 120 of FIG. 1) that comprises a first hybrid image icon 605a, and the second focal footprint 601b covers an area in the array of image icons that comprises a second hybrid image icon 605b. In this illustrated example, the hybrid image icon 605a includes a first component 610a. According to various embodiments, the first component 610a includes an area of ​​material in the icon layer (e.g., a UV-curable polymer of a first color that fills a recess in a holding structure). In some embodiments, the first component 610a is part of a surface mounted image icon. The expression "surface mounted image icon" as used in this disclosure encompasses a portion of material in the icon layer that contributes to the formation of an emergent image and whose position is not predefined by the position of the holding structure. In some embodiments, the surface mounted image icon can be formed by directly curing a layer of uncured icon material by irradiating the curing light through a focusing element, thereby focusing the curing light on a selected subset of the focal footprint of the particular image icon. According to some embodiments, the first hybrid image icon 605a further comprises a second component 615a, which for some embodiments is similar in configuration to the first component 610a, except that the second component 615a is formed of a material of a different color than the first color used for the first component 610a. Similarly, the second hybrid image icon 605b comprises a first component 610b of a similar configuration to the first component 610a, and a second component 615b of a similar configuration to the second component 615a.

[0047] According to various embodiments, the first focal footprint 601a and the second focal footprint 601b are two of a much larger number (e.g., millions or billions) of focal footprints of a micro-optical system (e.g., the micro-optical system 100 of FIG. 1) that can project a first emergent image of a first component of a hybrid pictorial icon and a second emergent image of a second component of a hybrid pictorial icon at a given viewing angle. As discussed elsewhere in this disclosure, the projection of the emergent image is a function of, but not limited to, how the components of the pictorial icon layer are arranged to repeat along one or more repeat axes (e.g., the first repeat axis 620) relative to how the focusing elements are arranged to repeat along the same repeat axis. Parameters describing the repetition of the first set of icon structures relative to the focusing elements and other icon structures define the topological space of the icon structures.

[0048] 6, the first components of the hybrid image icons 605a and 605b (i.e., first components 610a and 610b) occupy a first topological space. Similarly, the second components of the hybrid image icons 605a and 605b (i.e., second components 615a and 615b) occupy a second topological space. By subdividing the image icons into components occupying separate topological spaces, certain embodiments according to the present disclosure can generate previously unseen emergent image effects based on choreographed projections of two or more emergent images as the micro-optical device is tilted within a single angular viewing space.

[0049] As shown in the illustrative example of FIG. 6, the focusing elements associated with the first focal footprint 601a and the second focal footprint 601b are repeated along a first repeat axis 620 over a first interval 625. According to a particular embodiment, the lens pitch is a quotient of the first interval 625 to a common unit of measurement. The pitch can be expressed, for example, as lenses per inch. Furthermore, the first components 610a and 610b of the hybrid image icon are repeated at a first component interval 630. The ratio of the first component interval 630 to the first interval 625 along the first repeat axis 620 defines a first repeat ratio. Depending on the magnitude of the first component interval 630 relative to the first interval 625, the emergent image of the first components appears either above or below the plane of the micro-optical security device. Additionally, the first components 610a and 610b are separated from the second components 615a and 615b by offsets 635a and 635b. Depending on the embodiment, the relative values ​​of the offsets 635a and 635b may be constant. Alternatively, the magnitude of the offsets 635a and 635b may vary across the micro-optical device if the second component spacing 640 at which the second components of the pictorial icon are repeated along the first repeat axis 620 is different from the first component spacing 630. According to certain embodiments, the repeat ratio between the first component spacing 630 and the first spacing 625, together with the characteristics of the offsets 635a and 635b, define a first topological space for the first components of the hybrid pictorial icons 605a and 605b. Note that in certain embodiments, the topological space of the components of the pictorial icon may vary across the pictorial icon array, with the first components having a given topological space at one location in the array and a different topological space at other locations. In this manner, the emergent image projected by the first component of the micro-optical system's hybrid image icon may appear three-dimensional.

[0050] Similarly, the repetition ratio between the second component spacing 640 and the first spacing 625, in combination with the magnitude and variation of the offsets 635a and 635b, defines a second phase space for the second components of the hybrid image icons 605a and 605b. Like the first phase space, the second phase space can also vary locally within the image icon layer of the micro-optical device of which the hybrid image icons 605a and 605b are a part.

[0051] 7 shows examples of focal footprints and hybrid image icons with three components according to various embodiments of the present disclosure. Although the previous figures describe examples of micro-optical systems with multi-phase icon structures with reference to hybrid icons having two components, embodiments according to the present disclosure are not so limited and embodiments having hybrid icons with three or more components are within the contemplated scope of the present disclosure.

[0052] 7, a first focal footprint 701a and a second focal footprint 701b are shown in the figure. Further, a first hybrid image icon 705a is disposed within the first focal footprint 701a and a second hybrid image icon 705b is disposed within the second focal footprint 701b.

[0053] As shown in FIG. 7, each of the first hybrid image icons 705a and 705b includes a first component 710a and 710b, which includes a region of colored icon material that occupies a first topological space and projects a first emergent image in a given angular space. The hybrid image icons 705a and 705b further include a second component 715a and 715b, which also includes a region of colored icon material of a different color than the first components 710a and 710b, which occupies a second topological space and projects a second emergent image in a given angular space. The hybrid image icons 7015a and 7015b further include a third component 720a and 720b, which includes a material of a different color than either the first components 710a and 710b or the second components 715a and 715b. Additionally, third components 720a and 720b occupy a third topological space and project a third emergent image in the given angular space.

[0054] An example optical security device according to some embodiments of the present disclosure includes a light collection element array with light collection elements spaced apart at a first pitch along a first repeat axis, each light collection element of the light collection element array being associated with a focal footprint at a first focal depth, and an icon layer disposed at the first focal depth relative to the light collection element array, the icon layer comprising an array of hybrid image icons, each of the hybrid image icons comprising a first component associated with a first emergent image projected by the optical security device and a second component associated with a second emergent image projected by the optical security device, the first components of the hybrid image icons being repeated along the first repeat axis such that the first components of the hybrid image icons occupy a first phase space within the focal footprints of the light collection elements of the light collection element array. The second component of the hybrid image icon is repeated along the first repeat axis such that the second component of the hybrid image icon occupies a second phase space within a focal footprint of a focusing element of the focusing element array.

[0055] Examples of optical security devices according to some embodiments of the present disclosure include optical security devices in which the focusing elements of the array of focusing elements comprise hexagonal or aspherical focusing elements.

[0056] Examples of optical security devices according to some embodiments of the present disclosure include optical security devices in which the focusing elements of the array of focusing elements comprise spherical focusing elements.

[0057] Examples of optical security devices according to some embodiments of the present disclosure include an optical security device in which the first component of the hybrid image icon is repeatedly arranged along the first repeat axis with a first repeat ratio relative to the first pitch, and the second component of the hybrid image icon is repeatedly arranged along the first repeat axis with a second repeat ratio relative to the first pitch, the first repeat ratio being equal to the second repeat ratio.

[0058] Examples of optical security devices according to some embodiments of the present disclosure include an optical security device in which the first component of the hybrid image icon is repeatedly arranged along the first repeat axis with a first repeat ratio relative to the first pitch, and the second component of the hybrid image icon is repeatedly arranged along the first repeat axis with a second repeat ratio relative to the first pitch, the first repeat ratio being different from the second repeat ratio.

[0059] Examples of optical security devices according to some embodiments of the present disclosure include optical security devices where at least one of the first emergent image and the second emergent image is a dynamic emergent image.

[0060] Examples of optical security devices according to some embodiments of the present disclosure include an optical security device, wherein the first component of the hybrid image icon is a first color and the second component is a second color, the second color contrasting with the first color.

[0061] Examples of optical security devices according to some embodiments of the present disclosure include optical security devices in which the first emergent image includes at least one periodically repeating band of the first color that moves through a first region of the optical security device in response to a change in viewing angle, and the second emergent image includes at least one periodically repeating band of the second color that moves through the first region of the optical security device in response to a change in viewing angle.

[0062] Examples of optical security devices according to some embodiments of the present disclosure include optical security devices, wherein the focusing elements of the array of focusing elements include lenticular focusing elements.

[0063] Examples of optical security devices according to some embodiments of the present disclosure include an optical security device, wherein each hybrid image icon further comprises a third component associated with a third emergent image projected by the optical security device, and wherein the third components of the hybrid image icons are repeated along the first repeat axis such that the third components of the hybrid image icons occupy a third phase space within the focal footprint of a focusing element of the focusing element array.

[0064] Examples of optical security devices according to some embodiments of the present disclosure include an optical security device, wherein the first phase space is a function of a first repetition ratio between the first component of the hybrid image icon and the first pitch of the focusing elements along the first repetition axis and an offset between the first component and other components of the hybrid image icon.

[0065] An example method of manufacturing an optical security device according to various embodiments of the disclosure includes providing an array of focusing elements with focusing elements spaced apart at a first pitch along a first repeat axis, each focusing element of the focusing element array being associated with a focal footprint at a first focal depth, and providing an icon layer disposed at the first focal depth relative to the array of focusing elements, the icon layer comprising an array of hybrid image icons, each hybrid image icon comprising a first component associated with a first emergent image projected by the optical security device and a second component associated with a second emergent image projected by the optical security device, the first components of the hybrid image icons being repeated along the first repeat axis such that the first components of the hybrid image icons occupy a first phase space within the focal footprints of the focusing elements of the focusing element array. The second component of the hybrid image icon is repeated along the first repeat axis such that the second component of the hybrid image icon occupies a second phase space within a focal footprint of a focusing element of the focusing element array.

[0066] An example method of manufacturing an optical security device according to various embodiments of the present disclosure includes a method wherein the first phase space is a function of a first repetition ratio between the first component of the hybrid image icon and the first pitch of the focusing elements along the first repetition axis and an offset between the first component and other components of the hybrid image icon.

[0067] Examples of methods for manufacturing optical security devices according to various embodiments of the present disclosure include methods in which the focusing elements of the array of focusing elements include hexagonal or aspherical focusing elements.

[0068] An example method of manufacturing an optical security device according to various embodiments of the present disclosure includes a method in which the focusing elements of the array of focusing elements include spherical focusing elements.

[0069] An example method of manufacturing an optical security device according to various embodiments of the present disclosure includes a method in which the first component of the hybrid image icon is repeatedly arranged along the first repeat axis with a first repeat ratio relative to the first pitch, and the second component of the hybrid image icon is repeatedly arranged along the first repeat axis with a second repeat ratio relative to the first pitch, the first repeat ratio being equal to the second repeat ratio.

[0070] Examples of methods for manufacturing an optical security device according to various embodiments of the present disclosure include a method in which the first component of the hybrid image icon is repeatedly arranged along the first repeat axis with a first repeat ratio relative to the first pitch, and the second component of the hybrid image icon is repeatedly arranged along the first repeat axis with a second repeat ratio relative to the first pitch, the first repeat ratio being different from the second repeat ratio.

[0071] An example method of manufacturing an optical security device according to various embodiments of the present disclosure includes a method in which the first component of the hybrid image icon is a first color and the second component is a second color, the second color contrasting with the first color.

[0072] An example method of manufacturing an optical security device according to various embodiments of the present disclosure includes a method in which the first emergent image includes at least one periodically repeating band of the first color that moves through a first region of the optical security device in response to a change in viewing angle, and the second emergent image includes at least one periodically repeating band of the second color that moves through the first region of the optical security device in response to a change in viewing angle.

[0073] An example method of manufacturing an optical security device according to various embodiments of the present disclosure includes a method in which the focusing elements of the array of focusing elements include lenticular focusing elements.

[0074] Nothing in this application should be construed as implying that any particular element, step, or function is an essential element that must be included in the claims. The scope of patented subject matter is defined solely by the claims. Moreover, none of the claims are intended to invoke 35 U.S.C. 112(f) unless the precise words "means for" are followed by a participle.

Claims

1. An optical security device (100), comprising: a focusing element array (105) having focusing elements spaced apart at a first pitch along a first repeat axis (415), each focusing element of the focusing element array being associated with a focal footprint at a first focal depth; an icon layer (120) disposed at the first focal depth relative to the array of light collecting elements, the icon layer (120) comprising an array of hybrid image icons; Equipped with Each of the hybrid image icons (410) comprises a first component (410a) associated with a first emergent image projected by the optical security device and a second component (410b) associated with a second emergent image projected by the optical security device; the first component of the hybrid image icon is repeated along a first repeat axis such that the first component of the hybrid image icon occupies a first phase space within a focal footprint (701 a) of a focusing element of the focusing element array; the second component of the hybrid image icon is repeated along the first repeat axis such that the second component of the hybrid image icon occupies a second phase space within a focal footprint of a focusing element of the focusing element array; Optical security devices.

2. The optical security device of claim 1 , wherein the focusing elements of the array of focusing elements include hexagonal or aspherical focusing elements.

3. The optical security device of claim 1 , wherein the focusing elements of the array of focusing elements include spherical focusing elements.

4. the first component of the hybrid pictorial icon is repeatedly arranged along the first repeat axis at a first repeat ratio relative to the first pitch; the second components of the hybrid pictorial icon are repeatedly arranged along the first repeat axis at a second repeat ratio relative to the first pitch; the first repeat rate is equal to the second repeat rate; 10. The optical security device of claim 1.

5. the first component of the hybrid pictorial icon is repeatedly arranged along the first repeat axis at a first repeat ratio relative to the first pitch; the second components of the hybrid pictorial icon are repeatedly arranged along the first repeat axis at a second repeat ratio relative to the first pitch; the first repeat rate is different from the second repeat rate; 10. The optical security device of claim 1.

6. The optical security device of claim 1 , wherein at least one of the first emergent image and the second emergent image is a dynamic emergent image.

7. the first component of the hybrid graphical icon is a first color; the second component is a second color, the second color contrasting with the first color; 10. The optical security device of claim 1.

8. the first emergent image includes at least one periodically repeating band of the first color that moves through a first region of the optical security device in response to a change in viewing angle; the second emergent image includes at least one periodically repeating band of the second color that moves through the first region of the optical security device in response to a change in viewing angle; 8. The optical security device of claim 7.

9. The optical security device of claim 1 , wherein the focusing elements of the array of focusing elements comprise lenticular focusing elements.

10. each of the hybrid image icons further comprises a third component associated with a third emergent image projected by said optical security device; the third component of the hybrid image icon is repeated along the first repeat axis such that the third component of the hybrid image icon occupies a third phase space within a focal footprint of a focusing element of the focusing element array; 10. The optical security device of claim 1.

11. 2. The optical security device of claim 1, wherein the first phase space is a function of a first repetition ratio between the first component of the hybrid image icon and the first pitch of the focusing elements along the first repetition axis and an offset between the first component and other components of the hybrid image icon.

12. 1. A method of manufacturing an optical security device, comprising: providing a focusing element array (105) having focusing elements spaced apart at a first pitch along a first repeat axis (415), each focusing element of the focusing element array being associated with a focal footprint at a first focal depth; providing an icon layer (120) disposed at the first focal depth relative to the array of light collecting elements, the icon layer comprising an array of hybrid image icons; Including, Each of the hybrid image icons (410) comprises a first component (410a) associated with a first emergent image projected by the optical security device and a second component (410b) associated with a second emergent image projected by the optical security device; the first component of the hybrid image icon is repeated along a first repeat axis such that the first component of the hybrid image icon occupies a first phase space within a focal footprint (701 a) of a focusing element of the focusing element array; the second component of the hybrid image icon is repeated along the first repeat axis such that the second component of the hybrid image icon occupies a second phase space within a focal footprint of a focusing element of the focusing element array; method.

13. 13. The method of claim 12, wherein the first phase space is a function of a first repetition ratio between the first component of the hybrid image icon and the first pitch of the focusing elements along the first repetition axis and an offset between the first component and other components of the hybrid image icon.

14. The method of claim 12 , wherein the concentrating elements of the array of concentrating elements include hexagonal or aspherical concentrating elements.

15. The method of claim 12 , wherein the focusing elements of the array of focusing elements include spherical focusing elements.

16. the first component of the hybrid pictorial icon is repeatedly arranged along the first repeat axis at a first repeat ratio relative to the first pitch; the second components of the hybrid pictorial icon are repeatedly arranged along the first repeat axis at a second repeat ratio relative to the first pitch; the first repeat rate is equal to the second repeat rate; The method of claim 12.

17. the first component of the hybrid pictorial icon is repeatedly arranged along the first repeat axis at a first repeat ratio relative to the first pitch; the second components of the hybrid pictorial icon are repeatedly arranged along the first repeat axis at a second repeat ratio relative to the first pitch; the first repeat rate is different from the second repeat rate; The method of claim 12.

18. the first component of the hybrid graphical icon is a first color; the second component is a second color, the second color contrasting with the first color; The method of claim 12.

19. the first emergent image includes at least one periodically repeating first color band that moves through a first region of the optical security device in response to a change in viewing angle; the second emergent image includes at least one periodically repeating second color band that moves through the first region of the optical security device in response to a change in viewing angle; The method of claim 12.

20. The method of claim 12 , wherein the concentrating elements of the array of concentrating elements comprise lenticular concentrating elements.

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