RU2810914C2 - Using nanoparticles to adjust refractive index of polymer matrix layers to optimize microoptical (mo) focusing - Google Patents

Abstract

FIELD: security devices.

SUBSTANCE: invention is related to improving the characteristics of security devices, such as micro-optical strips. The security device includes a pictogram focusing element means, wherein each pictogram focusing element of the pictogram focusing element means is associated with a focal path. The device further comprises a layer of pictograms with one or more pictograms associated with a first characteristic colour and one or more pictograms associated with a second characteristic colour, and one or more areas between the pictograms containing a volume of substantially colourless material. At a first viewing angle, the colour is visible through each pictogram focusing element, and the colour visible through each pictogram focusing element at the first viewing angle is based on one or more colours of a first characteristic colour, a characteristic colour, or a substantially colourless material.

EFFECT: invention provides expanded functionality of the protective device.

20 cl, 26 dwg

Description

Field of technology to which the invention relates

[0001] The present invention generally relates to improving the performance of security devices, such as micro-optical stripes, or otherwise incorporated into security documents to provide tamper-resistant indicators of authenticity. More specifically, the present invention relates, without limitation, to micro-optical systems and methods for making them that include multi-layer pictogram coatings comprising multiple layers of pictograms. In addition, the present invention is also directed, without limitation, to certain embodiments of a micro-optical system that use nanoparticles to tune the refractive index of one or more components of a micro-optical system comprising a multilayer pictogram coating.

State of the art

[0002] In many cases, challenges in the design and manufacture of certain micro-optical security devices involve striking a balance between realizing the properties of the desired product and the capabilities and limitations imposed, for example, by available manufacturing technologies and the laws of physics. For example, manufacturers of security documents (for example, banknotes, checks and other documents that require reliable indicators of authenticity) desire micro-optical security devices that would have one or more of the following properties: they should be thin, durable, tamper-resistant and eye-catching . At the same time, the properties of the materials used, in combination with the laws of physics used to design micro-optical protective devices, can impose limitations on the performance of the finished products. As one non-limiting example, lenses made from a low refractive index material will be thicker than lenses of the same focal length made from a high refractive index material. As another non-limiting example, the interaction between light waves and the constituent materials of a lens can cause chromatic aberration, with the focal length of the lens varying for different wavelengths of light.

[0003] With that said, tuning the physical properties (e.g., component thicknesses and refractive indices) of micro-optical protective device materials represents a previously untapped opportunity to develop capabilities to realize a greater range of desired finished product characteristics (e.g., overall thickness, resistance to contamination) within the limits imposed by the laws of physics on the selected materials.

The essence of the invention

[0004] The present disclosure illustrates, without limitation, embodiments of systems and methods using nanoparticles to tune the refractive index of a polymer matrix to optimize micro-optical (“MO”) focusing, as well as embodiments of micro-optical systems using low refractive index materials in one or several constituent layers of the system.

[0005] In the first embodiment, the security device includes one or more pictogram means (systems), one or more refractive focusing element means (systems) pictograms and sealing layer. In addition, one or more pictogram refractive focusing element means are disposed on top of the one or more pictogram means such that a portion of one

or more refractive focusing pictogram means projects a synthetic image of a portion of the one or more pictogram means. In addition, one or more pictogram refractive focusing element means are in contact with the sealing layer along the non-planar boundary. In addition, at least one of the one or more pictogram refractive focusing element means (systems) and the sealing layer comprise a mixture of organic resin and nanoparticles having a first refractive index.

[0006] In a second embodiment, the security device comprises one or more pictogram refractive focusing element systems, and one or more pictogram refractive focusing element means (systems), the one or more pictogram refractive focusing element systems comprising a mixture of organic resin and nanoparticles. One or more pictogram refractive focusing element systems are positioned on top of the one or more pictogram systems such that a portion of the one or more pictogram refractive focusing element systems projects a synthetic image of a portion of the one or more pictogram systems. The mixture of organic resin and nanoparticles has a refractive index greater than 1.5.

[0007] In a third embodiment, the security document includes a substrate and a security device. The security device will contain one or more pictogram systems, one or more pictogram refractive focusing element systems, and a sealing layer. In addition, one or more pictogram refractive focusing element systems are disposed on top of the one or more pictogram systems such that a portion of the one or more pictogram refractive focusing element systems projects a synthetic image of a portion of the one or more pictogram systems. In addition, one or more pictogram refractive focusing element systems are in contact with the sealing layer along the non-planar boundary. In addition, at least one of the one or more pictogram refractive focusing element systems and the sealing layer comprise a mixture of organic resin and nanoparticles having a first refractive index.

[0008] In a fourth embodiment, the security document includes a substrate and a security device. The security device contains one or more pictogram systems, and one or more pictogram refractive focusing element systems, one or more pictogram refractive focusing element systems contains a mixture of organic resin and nanoparticles. One or more pictogram refractive focusing element systems are positioned on top of the one or more pictogram systems such that a portion of the one or more pictogram refractive focusing element systems projects a synthetic image of a portion of the one or more pictogram systems. The mixture of organic resin and nanoparticles has a refractive index greater than 1.5.

[0009] In a fifth embodiment, the security device includes one or more icon systems, one or more icon refractive focusing element systems, and a spacer layer located between the one or more icon systems and the one or more icon refractive element systems. The spacer layer contains a mixture of organic resin and nanoparticles. In addition, one or more pictogram refractive focusing element systems are positioned on top of the one or more pictogram systems such that a portion of the one or more pictogram refractive focusing element systems projects a synthetic image of a portion of the one or more pictogram systems. In addition, the mixture of organic resin and nanoparticles has a refractive index greater than 1.5.

[0010] In a sixth embodiment, the security document comprises a substrate, one or more icon systems, one or more icon refractive focusing element systems, and a spacer layer located between the one or more icon systems and the one or more icon refractive element systems. The spacer layer contains a mixture of organic resin and nanoparticles. In addition, one or more pictogram refractive focusing element systems are positioned on top of the one or more pictogram systems such that a portion of the one or more pictogram refractive focusing element systems projects a synthetic image of a portion of the one or more pictogram systems. In addition, the mixture of organic resin and nanoparticles has a refractive index greater than 1.5.

[0011] In a seventh embodiment, the security device includes an icon focusing element system, where each icon focusing element of the icon focusing element system is associated with a focal path, the icon layer includes one or more icons associated with a first characteristic color, and one or more icons, associated with a second characteristic color, and one or more areas between the pictograms containing a volume of substantially colorless material. In addition, at the first visual angle, the color is visible through each icon focusing element, and the color visible through each icon focusing element at the first visual angle is based on one or more colors of the first feature color, the second feature color, or, essentially a colorless material.

[0012] Other technical features will be apparent to one skilled in the art from the following figures, descriptions and claims.

[0013] Before providing the Detailed Description below, it may be advantageous to provide definitions of certain words and phrases used in this patent document. The term “to communicate” and its derivatives refers to any direct or indirect communication between two or more elements, whether those elements are in physical contact with each other or not. The terms “include” and “comprise”, as well as their derivatives, are intended to include without limitation. The term “or” is inclusive, meaning both/or. The phrase “associated with,” as well as its derivatives, means to include, to be included, to interact with, to contain, to contain, to join or connect with, to associate or associate with, to be in communication with, to cooperate with, to alternate with, to superimpose, to be connected or attached to, to contain, to have the property of , to have a relation or ratio, or something similar. The phrase “at least one of,” when used in conjunction with a list of objects, means that various combinations of one or more of the listed objects may be used, and only one object from the list may be required. 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.

[0014] Definitions of other specific words and phrases are provided in this patent document. Those skilled in the art will understand that in many, if not most cases, such definitions refer to both past and future uses of such specific words and phrases.

Brief description of drawings

[0015] In order to more fully understand the present specification and its advantages, reference will now be made to the following description taken in conjunction with the accompanying drawings, in which:

[0016] Figures 1A, 1B, and 1C illustrate examples of micro-optical security device elements and security documents containing micro-optical security devices according to certain embodiments of the present invention;

[0017] Figures 2A-2D illustrate aspects of adjusting the optical characteristics of the refractive focusing elements of the icons according to various embodiments of the present invention;

[0018] Figure 3 illustrates aspects of chromatic aberration associated with the passage of light of different wavelengths through the refractive focusing element of the icons;

[0019] Figure 4 illustrates an example of a plurality of icon systems positioned below a refractive index adjustable icon icon focusing element in accordance with some embodiments of the present invention;

[0020] Figure 5 illustrates visual effects aspects for a synthetic image created by a micro-optical security device according to certain embodiments of the present invention;

[0021] Figures 6A-6E illustrate example configurations of micro-optical security devices with a customizable nanoparticle seal layer according to various embodiments of the present invention;

[0022] Figures 7A-7E illustrate example configurations of micro-optical security devices with tunable refractive focusing elements of nanoparticle icons in accordance with certain embodiments of the present invention;

[0023] Figure 8 illustrates an example of a synthetic image containing combinations of feature colors of a first icon system associated with a first feature color and a second icon system associated with a second feature color, according to various embodiments of the present invention;

[0024] Figures 9A, 9B, and 9C illustrate aspects of generating synthetic images comprising feature color combinations of a first icon system associated with a first feature color and a second icon system associated with a second feature color; And

[0025] Figures 10A and 10B illustrate examples of micro-optical security devices according to various embodiments of the present invention.

Detailed description

[0026] Figures 1A through 10B, discussed below, and various other embodiments used to describe the principles of the present disclosure in this patent document are provided for illustrative purposes only and should not be construed as limiting the scope of the present invention in any way.

[0027] Figures 1A, 1B, and 1C illustrate examples of micro-optical security device elements and security documents containing micro-optical security devices according to certain embodiments of the present invention. For convenience, structural elements common to the examples of Figures 1A, 1B and 1C are numbered similarly (eg, substrate 105).

[0028] Referring to the non-limiting example of Figure 1A, herein, micro-optical security devices 100 and security documents 101 may be constructed as layered combinations of some or all of the elements shown in the illustrative example of Figure 1A.

[0029] As shown in the illustrative example of Figure 1A, security documents 101 include a substrate 105 to which a micro-optical security device 100 is attached. As used in the present invention, the term “secure document” covers documents that use a micro-optical security device to provide tamper-resistant visual indicators (for example, a synthetic image created by the spatial combination of one or more devices (systems) of pictograms with one or more refractive focusing elements of the pictograms) of the authenticity of the document. Examples of secure documents include, but are not limited to, bills, passports, tickets, trading cards, identification cards (such as driver's licenses).

[0030] In certain embodiments, the substrate 105 is a sheet of thin flexible fibrous material, such as banknote paper. In some embodiments, substrate 105 is a thin, flexible sheet of biaxially oriented polypropylene (BOPP) polymer film. In various embodiments, the backing 105 is a section of synthetic paper material, such as TESLIN®. According to some embodiments, the substrate 105 is a section of a polymeric card material, such as a polyethylene terephthalate (PET) blank of the type suitable for making credit cards and driver's licenses.

[0031] Referring to the non-limiting example of Figure 1A, here, micro-optical security device 100 includes one or more icon devices (systems) (110a and 110b). According to various embodiments, one or more icon systems include colored areas of pigmented material (e.g., colored area 112) arranged in a predetermined pattern (e.g., like icon designs that are to be synthetically enlarged by one or more icon refractive focusing element systems ). According to various embodiments, the colored area 112 contains a shaped volume of pigmented imaging material (eg, a pigmented UV-curable polymer). In certain embodiments, the colored area 112 has a width of approximately 1 μm or greater.

[0032] In certain embodiments, each of the one or more icon systems 110a and 110b is formed as a separate layer. In some embodiments, the pictogram system is formed by creating a pictogram layer structure (for example, by embossing a polymer matrix and curing it) to create holding structures, such as recesses or voids for holding one or more pigmented polymer materials, and then applying one or more pigmented polymer materials polymeric materials to create colored areas (eg, colored area 112) collectively defining a series of icons.

[0033] In various embodiments, for a given icon system, the pigmented polymeric material used to create the colored areas (eg, colored area 112) is designed such that all or a majority of the colored areas are filled with a characteristic color of polymeric material. As used herein, the term “characteristic color” covers the color associated with a specified wavelength of light or a set of wavelengths of light for which the focal length of the refractive focusing element of the icons matches the depth of the system of icons in the micro-optical security device 100.

[0034] As shown in the non-limiting example of Figure 1A, in certain embodiments of the present invention, micro-optical security device 100 includes two stacked icon systems (110a and 110b). Embodiments of the present invention are not limited to two icon systems, and embodiments with smaller or larger icon systems are also contemplated within the scope of this specification.

[0035] In various embodiments, the refractive index of the polymer matrix used to create retention structures (eg, retention structure 114) for one or more pigmented materials in one icon system (eg, icon system 110b) can be adjusted by adding nanoparticles to matrix for improving the focusing of light on another icon system (eg, on the icon system 110a).

[0036] In certain embodiments of the present invention, the micro-optical security device 100 is attached to the substrate 105 through adhesive bonding to the bottom surface of the icon system (eg, icon system 110a). In some embodiments, the micro-optical security device is attached to the substrate 105 as part of the manufacturing process of the substrate 105 (eg, like an inserted security thread into a sheet of banknote paper).

[0037] Referring to the non-limiting example of Figure 1A, here, in certain embodiments, the micro-optical security device 100 includes an optical spacer 115. In some embodiments, the optical spacer 115 includes a thin film of transparent material (eg, polyester) over which is applied, molded (eg, by embossing) and cures the polymer matrix to create pictogram refractive focusing elements and/or holding structures (eg, holding structure 114) for pigmented materials. In some embodiments, optical spacer 115 is formed as a polymer matrix layer and combined with one or more pictogram refractive focusing element systems. According to various embodiments, the optical properties of the micro-optical security device 100 (e.g., the quality of focus on the icon system or internal reflections in the security device) including an optical spacer 115 formed from a polymer matrix can be adjusted or tuned by changing the thickness of the optical spacer 115 and/or adjusting the concentration of nanoparticles in the polymer matrix used to form the optical spacer 115. In certain embodiments, the optical spacer 115 is formed from a polymer matrix suitable for use in forming the seal layer 125 or refractive focusing element 121. In various embodiments, the composition of the matrix used to forming the optical spacer 115 is specifically prepared so that it does not contain materials with a polarizing element such as iodine, bromine, chlorine or sulfur.

[0038] In addition, although in the non-limiting example of Figure 1A, micro-optical security device 100 is shown to include an optical spacer 115, embodiments of the present invention are not limited thereto. In certain embodiments, the optical spacer 115 may be absent. In addition, although in the non-limiting example of Figure 1A, the optical spacer 115 is shown to be physically distinct from the icon refractive focusing element system, embodiments of the present invention are not limited to this, and embodiments in which one or more icon refractive focusing element systems are formed by creating structural variations in the refractive index of the material used to create the optical spacer 115 are considered within the scope of the present invention.

[0039] Referring to the illustrative example of Figure 1A, here, in certain embodiments, the micro-optical security device 100 includes one or more systems of refractive focusing icons 120 that are positioned on top of one or more icon systems (e.g., icon systems 110a and 110b) such that that a portion of the one or more pictogram refractive focusing element systems projects a synthetic image of a portion of the one or more pictogram systems. As discussed elsewhere herein, in certain embodiments, two or more synthetic images are obtained, where each synthetic image is associated with a characteristic color.

[0040] As shown in the non-limiting example of Figure 1A, the refractive focusing element system 120 comprises a plurality of individual refractive focusing elements (e.g., refractive focusing element 121) arranged in a predetermined pattern relative to at least one icon system (e.g., a refractive focusing element 121). pictograms 110a). In certain embodiments, the colored areas of the icon system are substantially co-located in a plane defining the x and y axes of the coordinate system. In some embodiments, the centers of the refractive focusing elements are located at the same x and y values as the icons, but with different z coordinates. In some embodiments, the synthetic image may appear to be in the plane of the micro-optical protection device 100. In some embodiments, the center-to-center distance ( i.e., pitch) of the refractive focusing elements may differ slightly from the spatial period of the icons, and the synthetic image(s) may be observed above or below the plane of the micro-optical security device 100. In various embodiments, the centers of the refractive focusing elements may be slightly (eg, less than 1 degree) rotated relative to the icons, creating orthoparallactic motion effects.

[0041] In certain embodiments, refractive focusing element 121 comprises a volume of cured polymer matrix with at least one outer surface defining a non-planar boundary between a region of the first refractive index medium and a region of the second refractive index medium. Although, in the non-limiting example of Figure 1A, the refractive focusing element 121 is shown as having a flat bottom surface and a radially symmetric curved top surface, embodiments of the present invention are not limited to this. In some embodiments, the refractive focusing element may be a lenticular lens or may, for example, be curved on its top and bottom surfaces.

[0042] In some embodiments of the present invention, the refractive focusing element 121 is formed from a polymer matrix and, after curing, has a refractive index of less than 1.5. Examples of materials for use in such polymer matrices that have a refractive index of 1.5 or less include, but are not limited to, isodecyl acrylate, dipropylene glycol diacrylate, tripropylene glycol diacrylate, polyester tetraacrylate, trimethylolpropane triacrylate, and hexanediol diacrylate. Additional examples of materials suitable for forming the refractive focusing element 121 include substantially clear, translucent, colored or clear polymers such as acrylic polymers, acrylate polyesters, acrylate urethanes, epoxides, polycarbonates, polypropylenes, polyesters and urethanes. Other examples of materials that can be used to form matrices for forming the refractive focusing element 121 include, but are not limited to, acrylate monomers, acrylate oligomers, O-phenylphenoxyethyl acrylate, phenylthioethyl acrylate, bis-phenylthioethyl acrylate, cumylphenoxyethyl acrylate, biphenyl methyl acrylate, bisphenol A epoxy acrylates, fluorene-type acrylates, brominated acrylates, halogenated acrylates, melamine acrylates and combinations thereof. In certain embodiments, the matrix composition used to form the refractive focusing element 121 is specifically prepared and does not contain polarizing element materials such as iodine, bromine, chlorine or sulfur. As used herein, the term “polarizing element” covers elements that have a polarizability greater than carbon.

[0043] In various embodiments of the present invention, the refractive index of the material containing the refractive focusing element 121 can be tuned, or controlled by adding or adjusting the concentration of nanoparticles in the mixture of materials (for example, in a polymer matrix) used to form the refractive focusing element 121. According to In some embodiments, the refractive index of the material containing the refractive focusing element can be adjusted by adding to the mixture, for example, inorganic nanoparticles with a particle diameter of 100 nm or less. Examples of inorganic nanoparticles that can be added to the material mixture include, but are not limited to, nanoparticles of alumina, zirconia, titanium dioxide, zinc sulfide, or zinc telluride. In certain embodiments, adding nanoparticles to a material mixture can increase the refractive index of the material mixture used to form the refractive focusing element 121 from less than 1.5 to greater than 1.7. In some embodiments, refractive indices greater than 1.7 are possible when nanoparticles are added to the organic resin.

[0044] Referring to the non-limiting example of Figure 1A, herein, in various embodiments of the present invention, the micro-optical security device 100 further includes an encapsulation layer 125. According to various embodiments, the encapsulation layer 125 includes a smooth or substantially flat top surface 127 and a non-planar bottom surface 129, which provides a substantially continuous, non-planar boundary between the sealing layer 125 and the system of refractive focusing elements 120 icons. According to some embodiments, the seal layer 125 has a non-planar top surface that has fewer “pockets” than the interface between the seal layer 125 and the pictogram refractive focusing element system 120,

[0045] In certain embodiments, the sealing layer 125 contributes to the reliability and durability of the micro-optical protective device 100 by protecting one or more devices of the refractive focusing elements 120 of the icons and eliminating the space in which dirt, grease and other contaminants associated with use and handling security documents are collected in the space between the refractive focusing elements (for example, for the refractive focusing element 121). In addition, in certain embodiments, the seal layer 125 allows the use of additional layers of materials, such as external adhesives, without significantly affecting the focal length of the system.

[0046] According to various embodiments, the seal layer 125 is in contact with the refractive focusing elements of the icon refractive focusing elements device (e.g., for the refractive focusing elements of the pictogram devices 120, along a non-planar boundary at least partially defined by the bottom surface 129 of the seal layer 125 ). In certain embodiments, the seal layer 125 is formed from a material having a refractive index that is different from the refractive index of the material used to create the refractive focusing element 121.

[0047] In various embodiments, the seal layer 125 is formed from a polymer matrix and has a refractive index of less than 1.5 when cured. Examples of materials for use in such polymer matrices include those that have a refractive index of 1.5 or less, include, but are not limited to, isodecyl acrylate, dipropylene glycol diacrylate, tripropylene glycol diacrylate, polyester tetraacrylate, trimethylolpropane triacrylate, and hexanediol diacrylate. Other examples of materials suitable for forming the seal layer 125 include substantially clear, translucent, colored or clear polymers such as acrylic polymers, acrylate polyesters, acrylate urethanes, epoxides, polycarbonates, polypropylenes, polyesters and urethanes. Other examples of materials that can be used to form the matrix to form the sealing layer 125 include, but are not limited to, acrylate monomers, acrylate oligomers, O-phenylphenoxyethyl acrylate, phenylthioethyl acrylate, bis-phenylthioethyl acrylate, cumylphenoxyethyl acrylate, biphenyl methyl acrylate, bisphenol A epoxy acrylates, fluorene-type acrylates, brominated acrylates , halogenated acrylates, melamine acrylates and combinations thereof. In certain embodiments, the matrix composition used to form the seal layer 125 is specifically prepared and does not contain materials with a polarizing element such as iodine, bromine, chlorine or sulfur.

[0048] In certain embodiments, the seal layer 125 may be formed from materials that provide a large difference (eg, a difference greater than 0.1) in refractive index between the seal layer 125 and one or more icon refractive element devices 120. In certain embodiments, low refractive index materials suitable for use in the seal layer 125 include materials having a refractive index between 1.3 and 1.4, or materials having a refractive index less than 1.3. Examples of suitable low refractive index materials include, but are not limited to, mixtures of fluorinated acrylates and fluorinated urethane acrylates, which are measured to have refractive indices in the range of 1.3-1.35. Other examples of suitable low refractive index materials include, but are not limited to, certain perfluoropolyether compounds such as perfluoropolyether-caprolactone diacrylates.

[0049] In various embodiments of the present invention, the refractive index of the material constituting the seal layer 125 can be tuned or controlled by adding or adjusting the concentration of nanoparticles in the mixture of materials (eg, polymer matrix) used to form the seal layer 125. In some embodiments In an embodiment, the refractive index of the material containing the refractive focusing element can be adjusted by adding inorganic nanoparticles to the mixture, for example, having a particle diameter of 100 nm or less. Examples of inorganic nanoparticles that can be added to the material mixture include, but are not limited to, nanoparticles of alumina, zirconia, titanium dioxide, zinc sulfide, or zinc telluride. In certain embodiments, adding nanoparticles to a material mixture can increase the refractive index of the material mixture used to form the seal layer 125 from less than 1.5 to greater than 1.7. In some embodiments, refractive indices higher than 1.7 are possible by adding nanoparticles to the organic resin. Depending on the relative refractive index values between the sealing layer 125 and one or more pictogram refractive element devices 120, the shape of the interface between the two layers can be either convex or concave geometry. For example, and as shown in the illustrative example of FIG. 1A, when the material forming one or more refractive focusing element devices 120 has a higher refractive index relative to the material forming the seal layer 125, the refractive focusing elements will have a convex geometry. Likewise, when the sealing layer 125 is formed from a material having a higher refractive index than the one or more refractive focusing element systems 120, the refractive focusing elements will have a concave geometry.

[0050] Although, in the non-limiting example of Figure 1A, the micro-optical security device 100 is shown as including an encapsulation layer 125, embodiments of the present invention are not limited to this, and embodiments without an encapsulation layer 125 are contemplated within the scope of the present invention.

[0051] Figure 1B illustrates another non-limiting example of a micro-optical security device 100 according to various embodiments of the present invention. Referring to the non-limiting example of Figure 1B, herein, according to some embodiments, the micro-optical security device 100 comprises an unsealed (e.g., no encapsulation layer 125) system in which nanoparticles 117 are incorporated into a matrix used to create the optical spacer 115. According to some embodiments, by adjusting the concentration of nanoparticles 117 in the matrix used to create the optical spacer 115, certain optical properties (the F# and the effective focal length of the refractive focusing element 121 can be adjusted, for example).

[0052] Figure 1C illustrates another example of a micro-optical security device 100 according to various embodiments of the present invention. As illustrated in the non-limiting example of Figure 1C, herein, according to certain embodiments, the refractive index of the material constituting the seal layer 125 may be greater than the refractive index of the material comprising one or more refractive focusing pictogram element systems 120. In certain embodiments, depending on the relative refractive index shares of the sealing layer 125 and the one or more icon refractive element systems, they have a concave or plano-concave lens profile, as depicted in Figure 1C.

[0053] Figures 2A-2D illustrate aspects of adjusting the optical characteristics of the refractive focusing elements of the icons according to various embodiments of the present invention.

[0054] As discussed elsewhere herein, in many cases the design and manufacture of micro-optical security devices involves striking a balance between the implementation of the desired finished products and the limitations imposed by the materials of manufacture and the operation of the laws of physics on the selected materials. As one example, limited manufacturing precision in creating layers of refractive focusing elements and icons may impose limitations on the accuracy with which the refractive focusing element is focused appropriately on the icon. As another example, manufacturing precision may impose limitations on the amount of visual information (eg, details in a single synthetic image, or across different synthetic images) that can be placed in the focal region behind the refractive focusing element. In a system where the refractive index of the material used to construct the refractive focusing element is fixed, the laws of physics require that in order to increase the size of the design space (for example, the area of the icon layer in which icons and graphical information can be placed) behind the refractive focusing element, the thickness the focusing element necessarily increased. For many finished products (eg, banknotes), increasing the thickness of the focusing layer is undesirable, since thicker notes may be more prone to damage or jamming in related devices (eg, bill acceptors in vending machines).

[0055] As discussed with reference to the non-limiting example of Figures 2A-2D, certain embodiments of the present invention allow designers and manufacturers of micro-optical security devices to consider the refractive index of one or more components of a micro-optical security device as a tunable parameter, thereby reducing the extent to which designers and Manufacturers of micro-optical protective devices must balance desired performance characteristics (e.g., device thickness) to achieve another desired performance characteristic (e.g., increasing the amount of visual information under the refractive focusing element).

[0056] Referring to the non-limiting example of Figures 2A-2D, a refractive focusing element 200 is shown having a height h ₁ and a width w ₁ . According to certain embodiments, the refractive focusing element 200 is formed from a material containing at least an organic resin. In some embodiments, the organic resin has a refractive index of less than 1.5. In various embodiments, the refractive index of the refractive focusing element can be increased by adding nanoparticles to the polymer matrix used to create the refractive focusing element 200.

[0057] According to some embodiments, increasing the refractive index of the refractive focusing element 200 may facilitate the implementation of one or more desired properties of the finished product without seeking a balance with other desired properties of the finished product. For example, adding nanoparticles to increase the refractive index of a refractive focusing element can produce a thinner focusing element with the same focal length. For example, the refractive focusing element 205 has the same width (w ₁ ) and focal length as the refractive focusing element 200, but a smaller thickness (h ₂ < h ₁ ).

[0058] In certain embodiments, increasing the refractive index of the refractive focusing element 200 may catalyze an increase in the available area under the refractive focusing element, thereby allowing for increased visual information provided underneath the refractive focusing element without requiring an increase in the focusing element's thickness or manufacturing precision to encode visual information (for example, by creating a system of pictograms). For example, refractive focusing element 210, in which nanoparticles are added to a polymer matrix to form a refractive focusing element, has a higher refractive index. In this non-limiting example, the refractive focusing element 210 has the same thickness and focal length, but a larger diameter (w ₂ >w ₁ ) than the refractive focusing element 200, thereby allowing more visual information to be encoded under the refractive focusing element 210 than under refractive focusing element 200.

[0059] In many micro-optical security devices, imperfect focusing (that is, when the focal length of the refractive focusing element does not coincide with the depth of the icon at the wavelength(s) of interest) corresponds to poor contrast in synthetic images obtained with the micro-optical protective device. In certain embodiments, the focal length (f) refractive focusing element 215 having the same width and diameter as the refractive focusing element 200 can be adjusted over a range of distances (Δf) by changing the concentration of nanoparticles in the mixture of materials used to create the refractive focusing element 215. For example, increasing the concentration of nanoparticles in the mixture of materials corresponds to increasing the refractive index of the refractive focusing element 215, thereby decreasing the focal length of the refractive focusing element 215. Likewise, decreasing the concentration nanoparticles in the material mixture corresponds to a decrease in the refractive index of the refractive focusing element 215, thereby increasing the focal length of the refractive focusing element 215.

[0060] Although the non-limiting example of Figures 2A-2D describes the optical adjustment of a refractive focusing element by adjusting the concentration of nanoparticles in a mixture of materials, embodiments of the present invention are not limited to this. Properties of components of a micro-optical security device, such as an encapsulation layer (e.g., encapsulation layer 125 in Figure 1A), an optical spacer (e.g., optical spacer 115 in Figure 1A), or a holding structure for an icon system (e.g., holding structure 114 in Figure 1A), can also be tuned by changing the concentration of nanoparticles in a mixture of materials to change the refractive index of the components.

[0061] Although the illustrative examples of Figures 2A-2D are described with reference to a convex/plano-convex lens, embodiments of the present invention are not limited thereto, and nanoparticle-assisted optical tuning is possible in other lens shapes (e.g., convex lenses or plano-convex lenses). convex lenses).

[0062] Figure 3 illustrates aspects of chromatic aberration associated with the passage of light of different wavelengths through the refractive focusing element of the icons.

[0063] Referring to the illustrative example of Figure 3, a refractive focusing element 300 is shown suitable for use in a micro-optical security device (eg, micro-optical security device 100 in Figure 1A). In this illustrative example, the refractive focusing element 300 has a refractive index of approximately 1.5. Additionally, in the example of Figure 3, the refractive index of the refractive focusing element 300 can be tuned to higher values by adding nanoparticles to the material mixture used to form the refractive focusing element 300.

[0064] In this example, dispersion effects in the refractive focusing element 300 create chromatic aberration or spherochromatism, with light of different wavelengths being focused at different focal lengths. For example, the first ray of light 305 of a color associated with wavelength λ₁, passes through the refractive focusing element 300 and is focused at a point at the focal lengthf ₁. Likewise, a second beam of light 310 of the color associated with the longer wavelength λ₂ (for example, λ₂ > λ₁), passes through the refractive focusing element 300 and is focused at a point with a focal lengthf ₂ , which is greater than the focal lengthf _1,

[0065] In the context of a micro-optical security device, the chromatic aberration described above may have the effect of reducing the contrast between the colors of synthetic images produced by the micro-optical system, which users of the finished product may find undesirable. In addition, as the refractive index of the refractive focusing element 300 increases (eg, by adding nanoparticles to a material mixture), the degree of chromatic aberration (eg, the ratio of f ₂ to f ₁ ) may, depending on changes in matrix dispersion, become more pronounced. . Although chromatic aberration can be combated in telescopes and cameras by increasing the overall focal length of the focusing element, bringing the focal lengths for different wavelengths closer together, this approach is generally unacceptable in the context of micro-optical security devices and security documents where thick products are often useless. In addition, in certain embodiments, chromatic aberration can be combated by introducing a second lens, or doublet, formed from two materials with different dispersion properties.

[0066] Figure 4 illustrates an example of a plurality of icon systems located below a refractive icon focusing element, according to some embodiments of the present invention. According to certain embodiments of the present invention, by using nanoparticles to tune the refractive index of the refractive focusing element and/or other components of the micro-optical protection device, the effects of chromatic aberration described with reference to Figure 3 of the present description can be attenuated and optimized to produce synthetic images with unexpected visual characteristics. effects.

[0067] Referring to the illustrative example of Figure 4, a refractive focusing element 400 is shown as focusing a first light beam 405 of a first wavelength λ ₁ onto a first icon system 415. According to certain embodiments, the first icon system 415 includes one or more features (eg, colored area 112 in Figure 1) of a color associated with a wavelength corresponding to a specified wavelength range around the first wavelength λ _1. According to certain embodiments, in addition to the refractive focusing element 400, the first beam of light passes through other optical components (for example, through a spacer layer or sealing layer) of the micro-optical security device, which in combination with the refractive focusing element 400, has a first effective focal length f ₁ ^* for light of wavelength λ _1, According to certain embodiments, the value of f ₁ ^* can be adjusted by adjusting the concentration of nanoparticles in the refractive focusing element 400 and other components of the micro-optical security device such that the first beam of light 405 is focused on the first icon system 415.

[0068] As shown in the illustrative example of Figure 4, a refractive focusing element 400 is shown to focus a second beam of light 410 of a second wavelength λ ₂ onto a second icon system 420. In certain embodiments, the second icon system 420 includes one or more color features , associated with a wavelength corresponding to a specified range of wavelengths around the second wavelength λ _2. According to certain embodiments, in addition to the refractive focusing element 400, the first beam of light passes through other optical components (for example, through a spacer layer or sealing layer) of the micro-optical protective devices that, in combination with the refractive focusing element 400, have a second effective focal length f ₂ ^* for light of wavelength λ ₂ .

[0069] In some embodiments, because the second icon system 420 is located below the first icon system 415, the second beam of light 410 passes through additional structures 419 (eg, spacer layers or retention structures) of the micro-optical security device. In certain embodiments, the f ₂ ^* value can be adjusted to ensure that the second beam of light 410 is focused on the second icon system 420, for example, by adjusting the concentration of nanoparticles in the refractive focusing element 400 as well as additional structures 419.

[0070] Figure 5 illustrates aspects of visual effects in a synthetic image created by a micro-optical security device according to certain embodiments of the present invention.

[0071] Referring to the non-limiting example of Figure 5, the refractive focusing element 500 is shown as focusing a first beam of light 505 of a color (eg, blue) associated with wavelength λ ₁ through the micro-optical security device components so that it is focused onto the first system 515 icons at the effective focal length f ₁ ^* for light of wavelength λ _1. Likewise, in this illustrative example, the refractive focusing element is shown as focusing a second beam of light 510 of a color (eg, red) associated with the longer wavelength λ ₂ , through components (including additional components 519) of the micro-optical security device such that it focuses the second beam of light onto the second pictogram system 520 at an effective focal length f ₂ ^* for light of wavelength λ ₂ .

[0072] Referring to the non-limiting example of Figure 5, here, the effective focal length f ₁ ^* for light of wavelength λ ₁ is less than the effective focal length f ₂ ^* for light of wavelength λ ₂ . According to various embodiments, the above-described difference in effective focal lengths between f ₁ ^* and f ₂ ^* provides a wavelength-based difference for the F number. Stated another way, the features of the first pictogram system 515 of the first characteristic color associated with the wavelength λ ₁ form components the first characteristic color of the synthetic image projected by the micro-optical system. Likewise, the features of the second second characteristic color pictogram system 520 associated with wavelength λ ₂ form the second characteristic color components of the synthetic image projected by the micro-optical system.

[0073] Due to the difference between the effective focal length f ₁ ^* for light of wavelength λ ₁ and the effective focal length f ₂ ^* for light of wavelength λ ₂ , icons whose characteristic color is associated with light of wavelength λ ₁ are formed in the first system 515 pictograms, which is on a different layer than the second system 520 pictograms containing pictograms whose characteristic color is associated with light of wavelength λ ₂ . While all other factors are the same (eg, both icon systems produce similar optical effects), the layer height difference between the first icon system 515 and the second icon system described above causes the components of the synthetic image produced by the micro-optical security device of the first characteristic color to exhibit less change in position (Δ ₁ ) than the change in position ( _Δ2 ) of the components of the second characteristic color in response to a change in the position of vision. That is, in the non-limiting example of Figure 5, the red components of the synthetic image will appear to move further and faster in response to changes in visual position than the blue components of the synthetic image (ie , _Δ2 > _Δ1 ). Stated differently, the synthetic image from the first icon system 515 will appear to be on the short “lever arm” 550 compared to the longer “lever arm” 560 for the long wavelength components of the synthetic image from the second icon system 520. Thus, when the viewer adjusts the viewing angle of the micro-optical security device, the long wavelength components of the synthetic image (eg, red parts) on the second icon system 520 appear to move faster than the short wavelength components of the synthetic image (eg, blue parts) on the first system 515 pictograms. In certain embodiments, the relative “speed” of various colored components of a synthetic image may be an indicator of the authenticity of a security system feature.

[0074] Although the non-limiting examples of Figures 3-5 illustrate aspects of the optical effects produced by micro-optical systems according to certain embodiments containing lenses depicted as convex or plano-convex, embodiments of the present invention are not limited to this, and the examples of Figures 3-5 are applicable to embodiments employing a variety of lens geometries, including, but not limited to, concave or plano-concave lenses.

[0075] Figures 6A-6E illustrate five examples, designated a.) - e.) of micro-optical security device configurations with a customizable nanoparticle seal layer according to various embodiments of the present invention. Although certain embodiments are described with reference to the five embodiments shown in the exemplary examples of Figures 6A-6E, the present invention is not limited thereto, and additional configurations of micro-optical security devices with nanoparticle tunable encapsulation layers are possible and are within the scope of this disclosure. inventions.

[0076] Referring to the non-limiting examples of Figures 6A-6E, herein, certain micro-optical security devices of the present invention comprise a nanoparticle tunable encapsulation layer 600. In some embodiments, the nanoparticle tunable sealing layer 600 comprises the topmost (relative to the intended viewing position) layer of a micro-optical protective device, and it has a substantially flat top surface to resist the accumulation of dirt, grease, and other degradants to the ability micro-optical protective device to generate a synthetic image. According to various embodiments, the nanoparticle tunable seal layer 600 is constructed from a mixture of materials that contains an organic resin (e.g., an acrylate monomer or an acrylate oligomer) and one or more types of nanoparticles, the concentration of which in the material mixture controls the refractive index of the seal layer 600 , tunable using nanoparticles. In some embodiments, the concentration of nanoparticles is selected to achieve a predetermined refractive index difference between the nanoparticle tunable seal layer 600 and one or more icon refractive element systems 605, along the non-planar boundary between the nanoparticle tunable seal layer 600 and one or more several systems of refractive elements 605 pictograms. In the non-limiting examples shown in Figures 6A-6E, the nanoparticle tunable encapsulation layer 600 is constructed from a material having a higher refractive index than the refractive icon focusing elements 605, and as a result, the refractive icon focusing elements 605 have a concave lens geometry. . Other embodiments of the present invention, where the difference between the refractive indices of the encapsulation layer 600 and the refractive focusing elements 605 of the icons necessitate a convex lens geometry, are possible and are within the scope of the present invention.

[0077] As shown in the illustrative examples of Figures 6A-6E, micro-optical security devices according to certain embodiments of the present invention may include one or more systems of refractive focusing elements 605 icons. In certain embodiments, one or more refractive icon focusing element systems comprise a set of structures that define one or more non-planar boundaries between regions of different refractive indices and focus light of at least one wavelength onto icons in one or more icon systems 615 . In some embodiments, the refractive focusing elements in one or more icon refractive focusing element systems 605 are radially symmetrical. In certain embodiments, the refractive focusing elements are axially or translationally symmetrical (eg, lenticular lenses). In some embodiments, the one or more icon refractive focusing element systems comprise two or more icon refractive focusing element systems (eg, 605a and 605b). In certain embodiments, the use of multiple pictogram refractive focusing element systems may be desirable due to internal reflections, chromatic aberrations, or other undesirable visual effects. According to various embodiments, the refractive focusing elements of one or more icon refractive focusing element systems 605 have a diameter of 30 μm or greater. In various embodiments, the refractive icon focusing elements 605 have a size ranging between 7.5 and 25 μm.

[0078] In various embodiments of the present invention, micro-optical security devices with nanoparticle tunable encapsulation layers comprise an optical spacer 610. In some embodiments, the optical spacer 610 may be a sheet of material over which materials are deposited and formed to form other elements of a micro-optical protective device. In some embodiments, the optical spacer 610 is combined with another component (eg, a pictogram refractive focusing element system) of the micro-optical security device. In certain embodiments, depending on, for example, a difference in refractive index along the non-planar interface between the sealing layer and the icon refractive focusing element system, the optical spacer 610 serves to position one or more icon systems at the focal length of the icon refractive focusing element system.

[0079] As shown in the non-limiting examples of Figures 6A-6E, micro-optical security devices according to certain embodiments of the present invention comprise one or more icon systems 615 that are positioned below (relative to the intended viewpoint) one or more icon refractive focusing element systems such that a portion of one or more refractive focusing icon systems 605 projects a synthetic image of a portion of one or more icon systems 615. In certain embodiments, the micro-optical security device includes two or more icon systems (615a and 615b). In certain embodiments, each pictogram system includes features having a characteristic color, and each pictogram system is located at a depth or position within the micro-optical protective device relative to one or more pictogram refractive focusing element systems associated with the wavelength-dependent effective focal length of one or several systems of refractive focusing elements 605 pictograms.

[0080] In various embodiments of the present invention, micro-optical security devices with nanoparticle tunable seal layers further comprise a machine readable security device (Mr-SD) 620. In certain embodiments, the Mr-SD 620 comprises a layer of magnetic ink or another medium which, when passed through a suitable device such as a Banknote Evaluator (BEM), produces a characteristic emission or response spectrum for reliable verification of the validation criteria.

[0081] According to various embodiments, micro-optical security devices with a nanoparticle tunable encapsulation layer 600 have a device thickness of 50 microns or less. As used herein, the term “device thickness” covers the distance from the surface through which light enters the optical device to the surface (opposite the adhesive layer) that provides the interface between the micro-optical security device and the substrate to which the micro-optical security device is attached.

[0082] Figures 7A-7E illustrate five example configurations of micro-optical security devices that do not contain a nanoparticle tunable encapsulation layer, according to various embodiments of the present invention. Although certain embodiments are described with reference to the five embodiments shown in the illustrative examples of Figures 7A-7E, the present invention is not limited thereto, and additional configurations of micro-optical security devices are possible and are within the scope of the present invention.

[0083] As shown in the illustrative examples of Figures 7A-7E, micro-optical security devices according to certain embodiments of the present invention may include one or more systems of refractive focusing elements 705 icons. In certain embodiments, one or more refractive icon focusing element systems comprise a set of structures that define one or more non-planar boundaries between regions of different refractive indices and focus light of at least one wavelength onto icons in one or more icon systems 715 . In some embodiments, the refractive focusing elements of one or more icon refractive focusing element systems 705 are radially symmetrical. In certain embodiments, the refractive focusing elements are axially symmetrical (eg, lenticular lenses). In some embodiments, the one or more icon refractive focusing element systems comprise two or more icon refractive focusing element systems (eg, 705a and 705b). In certain embodiments, the use of multiple pictogram refractive focusing element systems may be desirable due to internal reflection, chromatic aberrations, or other undesirable visual effects. According to various embodiments, the refractive focusing elements of one or more icon refractive focusing element systems 705 have diameters of 30 μm or greater. According to various embodiments, the refractive focusing elements are formed from a mixture of materials that contains an organic resin and nanoparticles that, in combination, have a refractive index greater than 1.5. In some embodiments, the organic resin in the material mixture, itself, has a refractive index of less than 1.5. In certain embodiments, the organic resin in the material mixture has a refractive index of 1.4 or less.

[0084] In various embodiments of the present invention, micro-optical security devices that lack nanoparticle tunable sealing layers comprise an optical spacer 710. In some embodiments, the optical spacer 710 may be a sheet of material (e.g., polyester film) on top of which materials are applied and formed to form other elements of the micro-optical protective device. In some embodiments, the optical spacer 710 is combined with another component (eg, a pictogram refractive focusing element system) of the micro-optical security device. In certain embodiments, and depending, for example, on the difference in refractive index along the non-planar boundary between the refractive focusing element system of the icons and another medium (such as air), the optical spacer 710 serves to position one or more icon systems at the focal length of the refractive focusing system pictogram elements.

[0085] As shown in the non-limiting examples of Figures 7A-7E, micro-optical security devices according to certain embodiments of the present invention comprise one or more icon systems 715 that are positioned below (relative to the intended viewpoint) one or more icon refractive focusing element systems such that a portion of one or more refractive focusing elements 705 of icons projects a synthetic image of a portion of one or more icon systems 715 . In certain embodiments, the micro-optical security device has two or more icon systems (715a and 715b). In certain embodiments, each pictogram system includes features having a characteristic color, and each pictogram system is located at a depth, or position within the micro-optical protective device, relative to one or more pictogram refractive focusing element systems associated with a wavelength-dependent effective focal length one or more systems of refractive focusing elements 705 pictograms.

[0086] In various embodiments of the present invention, micro-optical security devices that do not contain nanoparticle-tunable seal layers further comprise a machine-readable security device (Mr-SD) 720. In certain embodiments, Mr-SD 720 includes a layer magnetic ink or other medium which, when passed through a suitable device such as a Banknote Examiner (BEM), produces a characteristic emission or response spectrum for reliable verification of the validation criteria.

[0087] In various embodiments, micro-optical security devices that do not contain a nanoparticle-tunable encapsulating layer can have a device thickness of 20-30 microns. In some embodiments, micro-optical security devices that do not contain nanoparticle-tunable encapsulation layers have a thickness of 20 microns or less. In certain embodiments, micro-optical security devices that do not contain a nanoparticle tunable encapsulating layer may have a device thickness of less than 15 microns.

[0088] Figure 8 illustrates an example of a synthetic image 800 comprising combinations of feature colors of a first icon system associated with a first feature color and a second icon system of a second feature color in accordance with various embodiments of the present invention.

[0089] Referring to the non-limiting example of Figure 8, here, a synthetic image provided by a micro-optical security device (eg, micro-optical security device 100 in Figure 1) as observed from a first viewing angle is shown in said figure. According to certain embodiments, the micro-optical security device projecting the synthetic image 800 includes a nanoparticle tunable refractive focusing element system (e.g., refractive focusing element system 120 in Figure 1A), wherein the refractive index of the focusing element is adjusted to focus light of a first wavelength on a first layer containing an icon system (eg, icon system 110b in Figure 1) associated with the first characteristic color. In this illustrative example, the first feature color is blue, although embodiments with other first feature colors are possible and are within the scope of the present invention. Likewise, the refractive index of the focusing elements of the micro-optical security device producing the synthetic image illustrated in Figure 8 is adjusted to also focus light of a second wavelength onto a second layer containing a second icon system (eg, icon system 110a in Figure 1) associated with second characteristic color. In this illustrative example, the second feature color is magenta, although embodiments with other second feature colors are possible and are within the scope of the present invention. Additionally, in some embodiments, the icon layers of the micro-optical security device projecting the synthetic image 800 include regions between the icons that are substantially colorless (eg, areas of transparent material defining the structures holding the icons).

[0090] As shown in Figure 8, the synthetic image 800 obtained from the first viewing angle contains shades or combinations consisting of a first feature color, a second feature color, and colorless areas. For example, synthetic image 800 includes an area 801 that is blue with the same shade of blue as the first feature color. Likewise, synthetic image 800 includes an area 803 that has a blue color that is a lighter shade of blue than the first characteristic color. In addition, the synthetic image 800 includes an area 805 that is magenta with the same shade of magenta as the second characteristic color. In addition, the synthetic image 800 includes an area 807 that is purple with a lighter shade of purple than the second characteristic color. In addition, the synthetic image 800 contains a region 809 that, like certain intermediate regions in icon layers, is substantially colorless. In addition, the synthetic image 800 includes an area 811 that is a shade of purple associated with a mixture of the first feature color and the second feature color. As shown in the non-limiting example of Figure 8, synthetic image 800 includes an area 813 that is a shade of purple associated with a second feature color and has a lighter shade of the first feature color (eg, a lighter shade of blue in area 803). Likewise, the synthetic image 800 includes an area 815 that has a shade of purple associated with a lighter shade of the first feature color (eg, a lighter shade of blue in the area 803), and with a lighter shade of the second feature color (eg, a lighter shade of blue in the area 803). shade of purple in area 807). Finally, in certain embodiments, the synthetic image 800 includes an area 817 that has a shade of purple associated with the first feature color and a lighter shade of the second feature color (eg, a lighter shade of purple in the area 807).

[0091] Thus, certain embodiments of the present invention provide the unexpected result of a two-color icon structure that allows one focusing element to contribute at least nine colors to the synthetic image created by a micro-optical system of which the icon structure and the focusing element are part. element. More generally, in certain embodiments of the present invention, the synthetic images produced by the security device in a first range of visual angles may comprise at least nine colors by modulating the positions of icons associated with the first characteristic color and icons associated with the second characteristic color, in two layers of pictograms.

[0092] In addition, in certain embodiments, colors other than the at least nine colors provided by a single focusing element projecting light from a structure of two or more pictogram layers can be obtained by aggregating the outputs of multiple focusing elements, wherein the color output is modulated according to various embodiments of the present invention. As a non-limiting example, consider a micro-optical security device region (eg, micro-optical security device 100) comprising micro-optical cells, each of which can output at least nine colors by modulating the position and presence of icons in two layers of an icon structure. As used in the present invention, the term “micro-optical cell” covers a three-dimensional section of a micro-optical security device corresponding to a single focusing element, such as shown in Figure 4 of the present description. By configuring the first fraction (e.g., one-third) of the micro-optical cells, the output is one of at least nine colors (e.g., a lighter shade of magenta in area 807 in Figure 8) produced by two layers of pictogram structure, and a second portions of the micro-optical cells output another of at least nine colors (eg, magenta, shown in area 805 of Figure 8). The region of the micro-optical cells will appear as a region of color that is a mixture of the colors produced by the output of the first and second lobes of the micro-optical cells in that region. Thus, in certain embodiments, extremely fine control of the colors provided by the micro-optical security system can be achieved by intermingling cells that output different colors from at least nine colors output from each micro-optical cell.

[0093] Figures 9A, 9B, and 9C illustrate aspects of generating synthetic images comprising feature color combinations of a first icon system associated with a first feature color and a second icon system associated with a second feature color.

[0094] Referring to the non-limiting examples of Figures 9A, 9B and 9C, here, in certain embodiments, combinations of a set of characteristic icon colors can be obtained by modulating the position of the icons relative to the focal point of the icons and the colorless areas in the icon layer.

[0095] Referring to the non-limiting example of Figure 9A, a first subsection 900 of a micro-optical security device (eg, micro-optical security device 100 in Figure 1) is shown. According to certain embodiments, the micro-optical security device includes an encapsulation layer 901 (e.g., encapsulation layer 125 in Figure 1), a plurality of focusing elements, including focusing elements 903, 905, and 907, and an optical spacer 913 (e.g., optical spacer 115 in Figure 1). . In some embodiments of the present invention, one or more elements of the seal layer 901, focusing elements 903, 905 and 907, or optical spacer 913 are constructed from a polymer matrix that contains nanoparticles to tune the refractive index of the layer. Additionally, in some embodiments of the present invention, and depending on the lens geometry selected for the focusing elements 903, 905 and 907 (e.g., convex or concave lenses), one or more of the seal layer 901 or the focusing elements 903, 905 and 907 are constructed from a low refractive index material, such as a material having a refractive index less than 1.4, a material having a refractive index between 1.30 and 1.35, or a material having a refractive index less than 1.3. In certain embodiments, one or more of the seal layer 901, the focusing elements 903, 905 and 907, or the optical spacer 913 are constructed from a polymer matrix that does not contain nanoparticles to adjust the refractive index of the layer.

[0096] As shown in the illustrative example of Figure 9A, the micro-optical security device further includes a first pictogram system associated with a first characteristic color (in this illustrative example, blue, although other colors are possible and are within the scope of the present invention), located in the first layer 909. In addition, in some embodiments of the present invention, the micro-optical security device includes a second pictogram system associated with a second characteristic color (in this illustrative example, magenta, although other colors are possible and are within the scope of the present invention) . In certain embodiments, the space between the icons of the first layer 909 and the second layer 911 contains a substantially colorless material (eg, an unpigmented polymer).

[0097] In certain embodiments, at a first viewing angle, each of the focusing elements 903, 905, and 907 focuses light entering the micro-optical security device into regions in the first layer 909 and the second layer 911 along paths converging at focal points 915, 917 and 919, respectively. For the same reasons, light leaves the micro-optical protection device from focal points 915, 917 and 919 along the same paths shown in the figure. As noted elsewhere herein, fine modulation of the positions of the pigmented icons relative to the path of light entering the micro-optical security device, in the direction associated with the first viewing angle, to each of focal points 915, 917 and 919 (referred to herein as “ focal path”) may combine the colors produced in the synthetic image provided by the micro-optical system other than the two characteristic colors used for the icons in the first layer 909 and the second layer 911.

[0098] As a first example, when both the icon 921a associated with the first feature color and the icon 921b associated with the second feature color lie on the same focal path for the focusing element, the synthetic image component provided by the focusing element 903 , has a color that is a mixture of the first characteristic color and the second characteristic color. In this non-limiting example, mixing the first characteristic color (cyan) with the second characteristic color (magenta) produces dark purple color 923.

[0099] As a second example, when the icon 925a associated with the first feature color is located at some distance from the focal path of the focusing element, and the icon 925b associated with the second feature color lies on the focal path, the synthetic image component provided by the focusing element 905, has a color that is a mixture of the first characteristic color, the colorless area and the second characteristic color. In this non-limiting example, positioned at some distance from the focal path, icon 925a produces color 927, which is a pinkish shade of mauve. Note that, in this non-limiting example, the contribution of the first feature color to color 927 is substantially attenuated due to the travel of some distance of the icon 925a from the focal path, while the contribution of the second feature color is substantially unchanged.

[0100] As a third example, when the icon 929a associated with the first feature color is on the focal path of the focusing element and the icon 929b associated with the second feature color is some distance from the focal path of the focusing element, the synthetic image component provided by the focusing element element 907 has a color 931 that is a mixture of the first feature color, the second feature color, and the substantially colorless areas between the icons of the second layer 911. In this particular example, the color 931 contains a bluish tint of purple. Note that in this illustrative example, the contribution of the first feature color is essentially unchanged, but the contribution of the second feature color to color 931 is attenuated due to the distance of icon 929b from the focal path.

[0101] Figure 9B provides other examples of achieving combinations of a limited set of characteristic colors in a synthetic image according to various embodiments of the present invention.

[0102] Referring to the non-limiting example of Figure 9B, here, the second micro-optical device subsection 991 is shown in Figure 9B. For ease of reference, the second subsection 991 uses the same design as the first subsection 900 shown in Figure 9A. As shown in this illustrative example, the second subsection 991 includes a sealing layer 901, focusing elements 903, 905 and 907, and an optical spacer 913, which are constructed equivalent to their respective embodiments described with reference to Figure 9A. Likewise, the second subsection 991 includes a first layer 909 and a second layer 911, which are equivalent to their respective embodiments in Figure 9A.

[0103] According to certain embodiments, at some distance of the icon 933 associated with the first feature color from the focal path of the focusing element, in the absence of an icon in the second layer 911, the synthetic image component provided by the focusing element 903 has a color 935 that represents a combination of the first feature color and a substantially colorless material in the first layer 909. In this particular example, color 935 is a lighter shade of the first feature color, which in this example contains a lighter shade of blue.

[0104] In some embodiments of the present invention, in the absence of an icon near the focal path of the focusing element 905 and with some distance of the icon 937 from the focal path, the synthetic image component provided by the focusing element 905 has a color 939, which is a combination of the second characteristic color and the substantially colorless material in the second layer 911. In this non-limiting example, color 939 is a lighter shade of the second characteristic color, which in this illustrative example comprises light pink.

[0105] In various embodiments of the present invention, at some distance of both the icon 941 associated with the first feature color and the icon 941b from the focal path of the focusing element 907, the synthetic image component provided by the focusing element 907 has a color 943, which is a combination of a first feature color, a second feature color, and a substantially colorless material in the first layer 909 and the second layer 911. In this non-limiting example, color 943 comprises lavender.

[0106] Referring to the non-limiting example of Figure 9C, here, the third micro-optical device subsection 993 is shown in Figure 9C. For ease of reference, the third subsection 993 uses the same design as the first subsection 900 shown in Figure 9A. As shown in this illustrative example, the third subsection 993 includes a sealing layer 901, focusing elements 903, 905 and 907, and an optical spacer 913, which are of the same construction as their respective embodiments described with reference to Figure 9A. Likewise, the third subsection 993 includes a first layer 909 and a second layer 911, which are the same as their respective embodiments in Figure 9A.

[0107] Referring to the non-limiting example of Figure 9C, herein, according to certain embodiments, by positioning the icon 945 associated with the first feature color on the focal path of the focusing element 903 and in the absence of positioning the icon associated with the second feature color on the focal path of the focusing element element 903 or near it, the color 947 of a synthetic image component projected by a portion of the focusing element 903 is a first characteristic color.

[0108] According to various embodiments, by positioning the icon 949 associated with the second feature color on the focal path of the focusing element 905, and in the absence of positioning the icon associated with the first feature color on or near the focal path of the focusing element 905, the focus color 951 contributes element 905 in the synthetic image represents a second characteristic color.

[0109] Likewise, in various embodiments of the present invention, in the absence of positioning any colored icons on or near the focal path of the focusing element 907, the contribution of the focusing element 907 to the synthetic image will be similar to the areas between the icons of the first layer 909 and the second layer 911 , essentially colorless.

[0110] Although modulation between combinations of characteristic colors in the examples of Figures 8 and 9A-C is described with reference to micro-optical systems using refractive focusing elements, embodiments of the present invention are not limited to this, and the color modulation effects described above can be obtained in systems using reflective focusing elements (eg, in micro-optical security device 100 in Figure 1C). In addition, although certain embodiments of the present invention are described, achieving modulation of the level of micro-optical cells of the color that the cell provides for a synthetic image, with reference to systems with a two-layer structure of icons, and icons associated with two characteristic colors, the present invention does not do so. limited. Embodiments including icon structures with more than two layers, as well as embodiments with icons associated with three or more characteristic colors, are within the intended scope of the present invention.

[0111] According to certain embodiments, additional micro-level detail (as used herein, the term “micro-level” covers the color visible through a single focusing element in the absence of a colored substrate) in the output colors with a finite set of characteristic icon element colors can be achieved by modulating the sizes of the icons associated with each characteristic color. In some embodiments, the size of the icons associated with a particular feature color can be modulated by one or more approaches, changing the line width of the linear icon, removing partial icons, or doubling the icons within the area occupied by the icon focus element.

[0112] In some embodiments of the present invention, additional macro-level detail (as used in the present invention, “macro-level” covers the colors visible when looking at many micro-optical cells at once) for colors can occur in response to small changes in viewing angle so that that among micro-optical cells with similar pictogram structures, the pictograms may border on being within the focal path of the pictogram focusing elements, resulting in regions that exhibit colors intermediate between those associated with combinations of the first and second characteristic colors. Area 819 in Figure 8 provides a non-limiting example of macro-level detail for the colors observed when viewing multiple micro-optical cells of a micro-optical security device simultaneously. As shown in Figure 8, in region 819, a visible gradual color transition can be observed, including many shades of characteristic color (as opposed to a sharp boundary) between two shades of color.

[0113] Figures 10A and 10B illustrate examples of a micro-optical security device according to certain embodiments of the present invention.

[0114] Referring to the non-limiting example of Figure 10A, this figure shows an example of a micro-optical security device 1000. In certain embodiments, the micro-optical device 1000 includes an encapsulation layer 1005, a refractive focusing element system 1010, an optical spacer 1015, and an icon layer 1020 containing a plurality of icons. 1025.

[0115] According to certain embodiments, the micro-optical security device 1000 includes a device capable of projecting a variety of synthetic images, including, without limitation, color shift effects, optically variable effects, and synthetically enlarged images of the contents of the icon layer 1020 that appear above and/or below the plane of the micro-optical protective device 1000. As shown in the illustrative example of Figure 10A, the seal layer 1005 is formed from a material having a higher refractive index than the material used to form the refractive focusing element system 1010. In some embodiments, the seal layer 1005 is formed from a material with a higher refractive index. refractive agent such as aromatic functionalized acrylate with dispersed zirconium oxide nanoparticles. As one non-limiting example, the seal layer 1005 is, in certain embodiments, a seal layer 1005 having a refractive index of approximately 1.6 and formed as a UV-cured layer of a liquid mixture of zirconia and acrylate monomer, a mixture of bisphenol fluorene diacrylate and o-phenylphenol ethyl acrylate , and the corresponding photoinitiator.

[0116] According to various embodiments, the refractive focusing element system 1010 is formed from a material having a refractive index of 1.5 or less. According to the lens formula equation for a given lens radius, the overall thickness of the micro-optical protective device 1000 can be reduced by increasing the refractive index difference between the material forming the seal layer 1005 and the material containing the refractive focusing element system 1010. In some embodiments, the refractive index difference between the two the above two materials is more than 0.1. In certain embodiments, the difference in refractive index between the material used to form the seal layer 1005 and the refractive focusing element system 1010 is between 0.1 and 0.15, and in some embodiments, the difference is between 0.16 and 0.20. In various embodiments, the refractive index difference is between 0.21 and 0.25, and in some embodiments, the refractive index difference is 0.26 or greater.

[0117] As an illustrative example, in at least one embodiment, the refractive focusing element system 1010 is formed from a layer of a mixture of UV-cured fluorinated acrylic materials having a refractive index of ~1.35, for example, from a mixture containing one or several fluorourethane acrylates, and a corresponding photoinitiator. Although not limited to compounds suitable for use as a low refractive index material in the micro-optical protective device 1000, fluorinated acrylic materials offer certain manufacturing advantages including, but not limited to, low tack, good adhesion to other acrylic materials, stain resistance, and chemical resistance. , and a glass transition temperature that is high enough to eliminate distortion or excess stickiness of the layer during manufacture. Other examples of materials suitable for refractive focusing element systems include, but are not limited to, silicone acrylates and silicone methacrylates.

[0118] As shown in the non-limiting example of Figure 10A, micro-optical security device 1000 includes an optical spacer 1015 (eg, optical spacer 115 in Figure 1A). In certain embodiments, the optical spacer 1015 is formed from a section of thin, substantially transparent film, such as 75-thick polyethylene terephthalate (PET). In various embodiments, the micro-optical security device 1000 includes an icon layer 1020 (for example, an icon layer 615 in Figures 6A -6E). In certain embodiments, the icon layer 615 comprises a set of cast and cured retention structures that are subsequently filled with a UV-curable material of one or more characteristic colors that is cured to form a plurality of icons (eg, icons 1025).

[0119] Those skilled in the art will note that the overall thickness of embodiments of the micro-optical security device 1000 may depend on a variety of application-specific variables, including the visual effects to be produced by the system, the desired lens size, and the number of icon layers. However, the refractive index difference between the encapsulation layer and the focusing elements is such that it is possible to have a total thickness of ~30 microns in a fully encapsulated spherical lens device capable of projecting synthetic images having a variety of optical effects (including, but not limited to, color shifting, multidirectional effects, or orthoparallactic motion) using a single layer of icons.

[0120] Although in the illustrative example of Figure 10A, the micro-optical security device 1000 is described with reference to a configuration in which the sealing layer 1005 contains a material having a higher refractive index than the refractive focusing element system 1010, embodiments of the present invention are not limited thereto.

[0121] Figure 10B illustrates an example of a micro-optical security device 1050 in which the relative positions of the high refractive index and low refractive index materials in the sealing layer 1005 and the refractive focusing element system 1010 are reversed. For ease of cross-referencing, structural elements of micro-optical security device 1050 that are common to micro-optical security device 1000 in Figure 10A are numbered similarly.

[0122] In some embodiments, the refractive index difference between the seal layer and the focusing elements may reverse sign such that the seal layer is formed from a material with a lower refractive index. In such embodiments, the geometry of the focusing elements is likewise switched from concave to convex lenses, as shown in Figure 10B. In addition, in certain embodiments, the refractive focusing element system 1010 includes a transition region 1030 between the curved (i.e., concave or convex) lens surfaces of the focusing elements and the optical spacer 1015. In certain embodiments, the presence of a transition region 1030 that provides minimum thickness in the refractive focusing element system 1010 improves the structural integrity of the micro-optical protective device 1050 by reducing the likelihood of individual focusing elements of the refractive focusing element system 1010 being “snapped” or otherwise separated from the system as a whole.

[0123] Likewise, although in the illustrative example of Figure 10A, the micro-optical security device 1000 is described with reference to an embodiment with a single-layer icon structure, embodiments of the present invention are not limited thereto. In certain embodiments, the micro-optical device has a multi-layer icon structure (eg, as shown with reference to Figures 9A-9C herein).

[0124] Examples of security devices according to certain embodiments of the present invention include a security device that includes one or more icon systems; one or more pictogram refractive focusing element systems; and a sealing layer, wherein the one or more pictogram refractive focusing element systems are disposed on top of the one or more pictogram systems such that a portion of the one or more pictogram refractive focusing element systems projects a synthetic image of a portion of the one or more pictogram systems; and , wherein one or more systems of refractive focusing pictogram elements are in contact with the sealing layer along the non-planar boundary.

[0125] Examples of security devices according to certain embodiments of the present invention include security devices wherein at least one of the one or more pictogram refractive focusing element systems and the sealing layer comprise a mixture of organic resin and nanoparticles having a first refractive index.

[0126] Examples of security devices according to some embodiments of the present invention include security devices wherein at least one of the icon refractive focusing element systems and the sealing layer comprise a low refractive index material, the low refractive index material having a second refractive index, and wherein the difference between the first refractive index and the second refractive index has a value of 0.1 or greater.

[0127] Examples of security devices according to some embodiments of the present invention include security devices where the low refractive index material has a refractive index between 1.3 and 1.4.

[0128] Examples of security devices according to some embodiments of the present invention include security devices where the low refractive index material has a refractive index of less than 1.3.

[0129] Examples of security devices according to some embodiments of the present invention include security devices where the low refractive index material comprises a fluorinated acrylate or a fluorinated urethane acrylate.

[0130] Examples of security devices according to some embodiments of the present invention include security devices where the low refractive index material contains a perfluoropolyether compound.

[0131] Examples of security devices according to some embodiments of the present invention include security devices where the nanoparticle mixture contains one or more alumina, zirconia, titanium dioxide, zinc sulfide, or zinc telluride nanoparticles.

[0132] Examples of security devices according to various embodiments of the present invention include security devices where the organic resin contains an acrylate monomer.

[0133] Examples of security devices according to various embodiments of the present invention include security devices where the organic resin contains an acrylate oligomer.

[0134] Examples of security devices according to certain embodiments of the present invention include security devices wherein the organic resin contains one or more of phenoxybenzyl acrylate, O-phenylphenoxyethyl acrylate, phenylthioethyl acrylate, bis-phenylthioethyl acrylate, cumylphenoxyethyl acrylate, biphenyl methyl acrylate, bisphenol A epoxy acrylate, fluorene type acrylate, bro regulated acrylate, halogenated acrylate or melamine acrylate.

[0135] Examples of security devices according to certain embodiments of the present invention include security devices where the organic resin contains one or more of isodecyl acrylate, dipropylene glycol diacrylate, tripropylene glycol diacrylate, polyester tetraacrylate, trimethylolpropane triacrylate, or hexanediol diacrylate.

[0136] Examples of security devices according to certain embodiments of the present invention include security devices where the organic resin does not contain a polarizing element.

[0137] Examples of security devices according to certain embodiments of the present invention include security devices that do not contain a sealing layer.

[0138] Examples of security devices according to some embodiments of the present invention include security devices where the sealing layer has a refractive index of 1.5 or higher.

[0139] Examples of security devices according to various embodiments of the present invention include security devices where the sealing layer has a refractive index of 1.6 or higher.

[0140] Examples of security devices according to various embodiments of the present invention include security devices wherein the pictogram refractive focusing element system comprises a transition region between lens surfaces of the pictogram refractive focusing element system and a spacer layer.

[0141] Examples of security devices according to various embodiments of the present invention include security devices wherein the icon refractive focusing element of one or more icon refractive focusing element systems has a diameter greater than 30 microns.

[0142] Examples of security devices according to various embodiments of the present invention include security devices wherein the icon refractive focusing element of one or more icon refractive focusing element systems has a diameter of less than 30 microns.

[0143] Examples of security devices according to certain embodiments of the present invention include security devices comprising a spacer layer located between a pictogram refractive focusing element system and a pictogram system, where the spacer layer contains nanoparticles.

[0144] Examples of security devices according to some embodiments of the present invention include security devices comprising a spacer layer combined with a system of pictogram refractive focusing elements.

[0145] Examples of security devices according to various embodiments of the present invention include security devices comprising two or more systems of refractive pictogram focusing elements in contact along one or more non-planar boundaries.

[0146] Examples of security devices according to some embodiments of the present invention include security devices where the security device has a thickness of 50 microns or less.

[0147] Examples of security devices according to certain embodiments of the present invention include security devices where the security device has a thickness of 20 microns or less.

[0148] Examples of security devices according to various embodiments of the present invention include security devices where the security device has a thickness of 15 microns or less.

[0149] Examples of security devices according to some embodiments of the present invention include security devices comprising a machine-readable security device (Mr-SD).

[0150] Examples of security devices according to certain embodiments of the present invention include security devices comprising two or more icon systems, where each icon system includes features having a characteristic color associated with the icon system, and where each icon system is located at a depth relative to one or more multiple systems of refractive focusing pictogram elements associated with a wavelength-dependent focal length associated with a characteristic color associated with the pictogram system.

[0151] Examples of security devices according to various embodiments of the present invention include security devices where the synthetic image contains shades of one or more characteristic colors moving at different speeds.

[0152] Examples of security devices according to some embodiments of the present invention include security devices comprising one or more icon systems; and one or more pictogram refractive focusing element systems, the one or more pictogram refractive focusing element systems comprise a mixture of organic resin and nanoparticles, wherein the one or more pictogram refractive focusing element systems are disposed on top of the one or more pictogram focusing element systems such that a portion of the one or more refractive focusing element systems pictogram elements projects a synthetic image of a portion of one or more pictogram systems, and where the mixture of organic resin and nanoparticles has a refractive index greater than 1.5.

[0153] Examples of security devices according to certain embodiments of the present invention include security devices where the organic resin has a refractive index of less than 1.5.

[0154] Examples of security devices according to various embodiments of the present invention include security devices where the mixture of organic resin and nanoparticles has a refractive index greater than 1.6.

[0155] Examples of security devices according to some embodiments of the present invention include security devices where the mixture of organic resin and nanoparticles has a refractive index greater than 1.7.

[0156] Examples of security documents according to certain embodiments of the present invention include a substrate attached to one or more security devices according to embodiments of the present invention.

[0157] Examples of security devices according to various embodiments of the present invention include security devices wherein the synthetic image comprises an area of a third color, the third color comprising a combination of at least one color of a first feature color or a second feature color.

[0158] Examples of security devices according to certain embodiments of the present invention include security devices wherein the synthetic images provided by the security device in a first range of visual angles comprise at least nine (9) colors, wherein the at least nine colors contain combinations of a first characteristic color and a second characteristic color.

[0159] Examples of security devices according to various embodiments of the present invention include security devices comprising an icon focusing element system, wherein each icon focusing element of the icon focusing element system is associated with a focal path, the icon layer comprising one or more icons associated with a first characteristic color, and one or more pictograms associated with a second characteristic color, and one or more areas between the pictograms containing a volume of substantially colorless material, where, for a given viewing angle, a color is visible through each focusing element of the pictograms, and, where color, visible through each focusing element of the pictograms at a first viewing angle, is based on one or more colors of a first characteristic color, a second characteristic color, or a substantially colorless material.

[0160] Examples of security devices according to some embodiments of the present invention include security devices where, in the absence of a colored substrate, the color visible through the icon focusing element at a first viewing angle when there are no icons located in the focal path of the icon focusing element or at some distance from it, is white, associated with a volume of essentially colorless material.

[0161] Examples of security devices according to certain embodiments of the present invention include security devices wherein, in the absence of a colored substrate, the color visible through the focusing element of the icons at a first viewing angle when the icon associated with the first characteristic color is at some distance from the focal path of the pictogram focusing element, has a component associated with the illuminated hue of the first characteristic color, and where, in the absence of a colored substrate, the color visible through the pictogram focusing element at the first viewing angle when the pictogram associated with the second characteristic color is at some distance from the focal path of the pictograms' focusing element, has a component associated with the illuminated hue of the second characteristic color.

[0162] Examples of security devices according to certain embodiments of the present invention include security devices wherein, in the absence of a colored substrate, the color visible through the icon focusing element comprises a combination of a group of combinations of a first characteristic color and a second characteristic color, comprising: a first color associated with the pictogram associated with the first characteristic color located on the focal path of the focusing element of the pictograms, and in the absence of the pictogram associated with the second characteristic color on or at some distance from the focal path of the focusing element of the pictograms, the second color associated with the pictogram associated with a second characteristic color located on the focal path of the pictogram focusing element, and in the absence of a pictogram associated with the first characteristic color on or some distance from the focal path of the pictogram focusing element, the third color contains the color white associated with a substantially colorless material , associated with the absence of any pictograms on the focal path of the pictograms focusing element or at some distance from it, a fourth color associated with the pictogram associated with the first characteristic color, at some distance from the focal path of the pictograms focusing element, and in the absence of a pictogram associated with the second a characteristic color, on or at some distance from the focal path of the focusing element of the pictograms, a fifth color associated with the pictogram associated with the second characteristic color, at some distance from the focal path of the focusing element of the pictograms, and in the absence of the pictogram associated with the first characteristic color on at or some distance from the focal path of the pictogram focusing element, a sixth color associated with the pictogram associated with the first characteristic color located on the focal path of the pictogram focusing element, and the pictogram associated with the second characteristic color located on the focal path of the pictogram focusing element, a seventh color associated with a pictogram associated with the first feature color located on the focal path of the pictograms focusing element, and a pictogram associated with the second feature color at some distance from the focal path of the pictograms focusing element, an eighth color associated with the pictogram associated with the second a characteristic color located on the focal path of the focusing element of the pictograms, and a pictogram associated with the first characteristic color at some distance from the focal path of the focusing element of the pictograms, and a ninth color associated with the pictogram associated with the first characteristic color at some distance from the focal path of the focusing element an icon element and an icon associated with a second characteristic color at some distance from the focal path of the focusing icon element. Examples of security devices according to certain embodiments of the present invention include security devices comprising a first icon associated with a first characteristic color and a second icon associated with a second characteristic color, wherein the ratio of the size of the first icon to the size of the second icon is such that, in the absence of a colored substrate, the color visible through the focusing element of the icons, contains a tenth color that does not correspond to any of the nine combinations of the first characteristic color and the second characteristic color.

[0163] Examples of security devices according to some embodiments of the present invention include security devices comprising one or more refractive icon focusing elements or reflective icon focusing elements.

[0164] Examples of security devices according to various embodiments of the present invention include security devices where the icon focusing elements comprise a mixture of organic resin and nanoparticles.

[0165] Examples of security documents according to various embodiments of the present invention include security documents that include a substrate and a security device attached to the substrate. In some embodiments, the security device comprises one or more pictogram systems, one or more pictogram refractive focusing element systems, and an encapsulation layer comprising an organic resin and nanoparticles. In some embodiments, one or more icon refractive focusing element systems are positioned on top of the one or more icon systems such that a portion of the one or more icon refractive focusing element systems forms a synthetic image of a portion of the one or more icon systems. In some embodiments, one or more icon refractive focusing element systems are in contact with the sealing layer along a non-planar boundary.

[0166] Examples of security documents according to various embodiments of the present invention include security documents that include a substrate and a security device attached to the substrate. In some embodiments, the security device comprises one or more pictogram systems and one or more pictogram refractive element systems, the one or more pictogram refractive focusing element systems comprising a mixture of organic resin and nanoparticles. In certain embodiments, one or more pictogram refractive focusing element systems are positioned on top of one or more pictogram systems such that a portion of the one or more pictogram refractive focusing element systems forms a synthetic image of a portion of the one or more pictogram systems. In some embodiments, the mixture of organic resin and nanoparticles has a refractive index greater than 1.5.

[0167] Examples of security documents according to certain embodiments of the present invention include security documents that include a substrate and a security device attached to the substrate. In some embodiments, the security device comprises one or more icon systems, one or more icon refractive focusing element systems, and a spacer layer disposed between the one or more icon systems and the one or more icon refractive focusing element systems, the spacer layer comprising a mixture of an organic resin and nanoparticles In certain embodiments, one or more pictogram refractive focusing element systems are positioned on top of one or more pictogram systems such that a portion of the one or more pictogram refractive focusing element systems forms a synthetic image of a portion of the one or more pictogram systems. In some embodiments, the mixture of organic resin and nanoparticles has a refractive index greater than 1.5.

[0168] Nothing contained in this application should be construed as a suggestion that any particular element, step, or function is essential to be included within the scope of the claims. The scope of the patented subject matter of the invention is determined only by the claims. Moreover, none of the claims are intended to require application of 35 U.S.C. § 112(f), unless the specific words “means for” are followed by a participle.

Claims (41)

1. Protective device (100, 900) containing: an icon focusing element means (120, 605, 705), where each icon focusing element of the icon focusing element means is associated with a focal path; an icon layer comprising one or more icons (110a, 909) associated with the first feature color and one or more icons (110b, 911) associated with the second feature color; And one or more areas between the pictograms containing a volume of substantially colorless material, wherein from the first viewing angle, the color is visible through each focusing element of the pictograms, and wherein the color visible through each focusing element of the pictograms at the first viewing angle is based on one or more colors of a first feature color, a second feature color, or a substantially colorless material. 2. Protective device according to claim 1, wherein, in the absence of a colored substrate, the color visible through the pictogram focusing element at a first viewing angle when there are no pictograms located on the focal path of the pictogram focusing element or outside the focal path is white, associated with a volume of substantially colorless material. 3. Protective device according to claim 1, wherein, in the absence of a colored substrate, the color visible through the pictogram focusing element at the first viewing angle when the pictogram (925a) associated with the first feature color is outside the focal path of the pictogram focusing element has a component associated with the illuminated hue of the first feature color, And wherein, in the absence of a colored substrate, the color visible through the pictogram focusing element at the first viewing angle when the pictogram (929b) associated with the second feature color is outside the focal path of the pictogram focusing element has a component associated with the illuminated hue of the second feature color. 4. The security device of claim 1, wherein, in the absence of a colored substrate, the color visible through the pictogram focusing element comprises a combination of a group of nine combinations of a first characteristic color and a second characteristic color, the group of nine combinations comprising: a first color (947) associated with an icon associated with a first feature color located on the focal path of the pictogram focusing element, and with no icon associated with the second feature color located on the focal path of the pictogram focusing element or outside the focal path, a second color (951) associated with an icon associated with a second feature color located on the focal path of the pictogram focusing element, and in the absence of an icon associated with the first feature color, on the focal path of the pictogram focusing element or outside the focal path, a third color comprising white, associated with a substantially colorless material, associated with the absence of any pictograms in the focal path of the pictograms focusing element or outside the focal path, a fourth color (935) associated with the pictogram associated with the first feature color, outside the focal path of the pictograms focusing element, and with the absence of an icon associated with the second feature color, in the focal path of the pictograms focusing element or outside the focal path, a fifth color (939) associated with the pictogram associated with the second feature color outside the focal path of the pictogram focusing element, and with the absence of the pictogram associated with the first feature color in the focal path of the pictogram focusing element or outside the focal path, a sixth color (923) associated with an icon associated with a first feature color located on the focal path of the pictogram focusing element and with an icon associated with a second feature color located on the focal path of the pictogram focusing element, a seventh color (931) associated with an icon associated with the first feature color located on the focal path of the pictogram focusing element, and with an icon associated with the second feature color outside the focal path of the pictogram focusing element, an eighth color (927) associated with an icon associated with a second feature color located on the focal path of the pictogram focusing element, and with an icon associated with the first feature color outside the focal path of the pictogram focusing element, and a ninth color (943) associated with the pictogram associated with the first feature color, outside the focal path of the pictogram focusing element, and with the pictogram associated with the second feature color, outside the focal path of the pictogram focusing element. 5. The protective device according to claim 4, additionally containing: a first pictogram associated with the first characteristic color; And a second pictogram associated with the second characteristic color, wherein the ratio of the size of the first icon to the size of the second icon is such that, in the absence of a colored substrate, the color visible through the focusing element of the icons contains a tenth color that does not correspond to any of the nine combinations of the first feature color and the second feature color. 6. The security device according to claim 1, comprising one or more refractive pictogram focusing elements or reflective pictogram focusing elements. 7. The protective device according to claim 1, containing pictogram focusing elements that contain a mixture of organic resin and nanoparticles. 8. The security device according to claim 7, wherein the organic resin has a refractive index of less than 1.5. 9. The security device of claim 7, wherein the nanoparticles comprise one or more of aluminum oxide, zirconia, titanium dioxide, zinc sulfide or zinc telluride nanoparticles. 10. The security device according to claim 7, wherein the organic resin contains an acrylate monomer. 11. The security device according to claim 7, wherein the organic resin contains an acrylate oligomer. 12. The security device according to claim 7, wherein the organic resin contains one or more of phenoxybenzyl acrylate, O-phenylphenoxyethyl acrylate, phenylthioethyl acrylate, bis-phenylthioethyl acrylate, cumylphenoxyethyl acrylate, biphenyl methyl acrylate, bisphenol A epoxy acrylate, fluorene type acrylate, brominated acrylate, halogenated acrylate ylate or melamine acrylate. 13. The security device of claim 7, wherein the organic resin contains one or more of isodecyl acrylate, dipropylene glycol diacrylate, tripropylene glycol diacrylate, polyester tetraacrylate, trimethylolpropane triacrylate or hexanediol diacrylate. 14. The protective device according to claim 7, wherein the organic resin does not contain a polarizing element. 15. The security device according to claim 7, wherein the mixture of organic resin and nanoparticles has a refractive index greater than 1.6. 16. The security device according to claim 7, wherein the mixture of organic resin and nanoparticles has a refractive index greater than 1.7. 17. The security device according to claim 1, further comprising a spacer layer (610, 710) located between the pictogram refractive focusing element means and the pictogram means, where the spacer layer contains nanoparticles. 18. The security device according to claim 17, wherein the spacer layer is integral with the pictogram focusing element means. 19. The security device according to claim 1, further comprising a machine readable security device (Mr-SD) (620, 720). 20. A security document (101) containing a security device according to claim 1.

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