JP5579363B2 - Providing a frame or border around pigment flakes for confidential security applications - Google Patents

Description

  The present invention relates generally to thin pigment flakes, and in particular is defined by the provision of a border or frame around the taggent flakes used in the coating composition, and one or more grooves in the framed region of the flakes. More specifically, the present invention provides a frame and a framed mark where the grooved frame is more fragile than the grooved mark and can be more easily crushed.

  Special pigments are intended for use in security applications, including counterfeit and pirated anti-diffusion devices printed on banknotes, high-priced product packaging, container seals, and even direct use on commercial products Has been developed. For example, the US $ 20 Federal Reserve currently uses optically variable ink. The number “20” printed in the lower right corner of the surface of the banknote changes color when the viewing angle changes. This is an overt counterfeit / pirated anti-diffusion device. The color shift action is not reproducible with a normal color copier, and the person receiving the banknote is provided with a color shift security feature to determine that it is a genuine note. Can be observed.

  Other high-value documents and objects use similar means. For example, iridescent or diffractive pigments are used in paints and inks that are applied directly to articles such as stock certificates, passports, original product packages, or seals affixed to the articles. As counterfeits and pirated boards continue to become more sophisticated, security features that make it more difficult to spread counterfeits and pirated copies are desired.

  One counterfeit / pirated anti-diffusion technique uses microscopic symbols on multilayer color-shifting pigment flakes. The symbol is formed on at least one of the layers of the multilayer color-shifting pigment flake by locally changing optical property (s) such as reflectance. Multilayer color shifting pigment flakes generally include a Fabry-Perot type structure having an absorbing layer separated from the reflective layer by a spacer layer. The reflective layer is typically a metal layer that renders the pigment flakes essentially opaque. When most of these types of pigment flakes are mixed with other pigments, the resulting color will be significantly different from that pigment, and if the amount of these flakes mixed with other pigments is too small Making them difficult to identify.

  Another technique uses polyethylene terephthalate ("PET") epoxy-encapsulated flakes. A reflective layer is deposited on a roll of PET and then the PET is cut. To increase the durability of the reflective layer, the flakes are coated with epoxy or encapsulated in epoxy. These flakes can be selected from a variety of shapes such as square, rectangular, hexagonal, and “apostrophe” shapes, as well as shades of reflective metals such as silver, white eye, gold and copper. However, since the epoxy layer and the PET substrate (used in the vacuum deposition process, typically with a minimum thickness of about 13 microns (0.5 mil)) is relatively thick, typically greater than 14 microns Relatively thick flakes. Unfortunately, such thick flakes are undesirable for use in covert applications where the thickness is much greater than the base pigment. Similarly, such thick flakes are less likely to flow in the ink and produce lumps in the paint. When the paint contains thick flakes that produce a rough surface, a relatively thick, clear overcoat is typically applied over the rough surface.

  It is desirable to mark objects with hidden counterfeit / pirated diffusion prevention devices that overcome the limitations of the above techniques.

  The present invention relates to the provision of flakes that have a taggent or covert symbol stamped, embossed or etched inside the flake by mechanical means, or formed by laser means, the covert symbol being visible with a microscope. . In order to preserve the integrity of the symbol, a frame around all or part of the confidential symbol is provided so that when individual flakes are removed from the support structure deposited thereon, the majority of the flakes Instead of breaking in an uncontrolled and unpredictable manner, penetrating through the symbol and more frequently around the symbol, it breaks along the provided frame line. As a further attempt to ensure that breakage occurs along the frame line or groove, the frame groove may have a different profile than the groove defining the covert symbol, where the frame groove is a covert groove. It is designed to be more susceptible to breakage or cracking. In some cases, parallel frame lines may be provided so that the flakes are broken into ribbons. In a preferred embodiment of the present invention, the flakes, particularly one or more symbols in the flakes, have a framed grooved border on more or less than four sides around the one or more symbols. By having the flakes break into a uniform rectangle or square along the frame line. Of course, it is also possible to provide triangular or hexagonal flakes by pre-framing the three sides of the symbol before removing the flakes from the substrate. A conventional release layer is provided so that the flakes can be easily removed from the substrate or support layer and so that the flakes break along the frame line after removal. The frame can be produced in a manner similar to the manner in which the symbols are produced using laser, etching or stamping of the film on the substrate. In a preferred embodiment, the frame is provided in the same process as the symbol formation.

  “Embossed flakes” used below are flakes that are embossed by applying pressure to the flakes with an embossing tool, or flakes that are formed on an embossed substrate by coating the embossed substrate in the form of a substrate. Means.

  Accordingly, it is an object of the present invention to provide flakes having a symbol thereon, from an embossed temporary support to protect the symbol during the process of separating the flake from the temporary support substrate. The symbol in the flake or molded flake has an embossed, etched or laser machined frame or boundary, or has previously, and the frame groove is deeper than the groove defining the mark or symbol in the frame And / or crushable.

  It is an object of the present invention to provide a frame groove having a different cross-sectional profile than the mark groove, which is designed to be more easily damaged or cracked than the mark groove.

  In another aspect of the invention, the substrate is pre-metallized prior to applying the release layer thereto. After the flakes are separated from the release layer, the embossed substrate is cut back to reflective flakes without being reused, resulting in another batch of coated flakes. The metal coated substrate is cut into elongated strips to create a new security device (ie, thread) that includes the same matching design as the flakes made with the substrate.

  In another aspect of the present invention, the “sized” flakes after being removed from the substrate and optionally post-processed to produce shaped / symbolized flakes are used for flakes during printing or painting applications. Encapsulated to enhance breakage durability.

According to the present invention, a plurality of pigment taggent flakes, each flake comprising a peripheral frame defined by a wall and a region within the frame, wherein at least one height of the wall of the frame is at least A height F _h , a region within the frame has indicia defined by one or more grooves formed therein, the grooves have a depth less than I _d , and F _h > I _d A plurality of pigment flakes are provided.

According to another aspect of the present invention, a sheet of taggent regions for forming taggent flakes, depth defining a frame to form a mark in a plurality of frames grooves and in each frame is F _h An embossed substrate having a plurality of mark grooves, wherein the mark groove depth is less than I _d and F _h > I _d , thereby separating the sheet or coating on the sheet into taggent flakes This provides a sheet with a substrate that is more likely to break along the frame groove than along the mark groove.

  According to another aspect of the present invention, there is provided a coating composition comprising a carrier and a plurality of single-layer inorganic dielectric-covered taggent flakes dispersed on the carrier, wherein the flakes are surrounded by a frame, A coating composition is provided in which an identifiable symbol is formed in the region of the frame and the frame wall is deeper than the groove wall defining the identifiable symbol.

  According to another aspect of the present invention, there is provided a method of making a flake having indicia thereon, the method comprising the steps of providing a substrate coated with a release layer, and 1 on the release layer. Providing an optical coating of one or more layers, and imprinting in the form of one or more symbols on a plurality of areas on the optical coating, the imprinted marks being formed in the optical coating A step in the form of one or more grooves, and a step in which a grooved frame is imprinted around the mark in each region, wherein the grooved frame is deeper than the groove or grooves forming the mark; Removing the optical coating from the release layer such that the coating is broken along the grooved frame into flakes in the form of framed indicia.

  In yet another aspect of the invention, flakes having at least one symbol thereon are provided, the flakes having flakes along a grooved frame or boundary processed by etching, laser or embossing. By separating into a support sheet, the flakes are separated from adjacent flakes before the flakes are removed from the support sheet, and the frame or boundary defining the periphery of the flake is broken more than at least one symbol thereon It is easy to do.

  According to another aspect, the present invention provides a plurality of embossed pigment-enclosed taggent flakes coated with a light transmissive non-conforming coating that reduces the depth of grooves in the flakes. provide.

  Exemplary embodiments will now be described with reference to the drawings.

I. Introduction Confidential security flakes are typically not visible during routine observation. Certain inspection techniques, such as inspection using a microscope, or analysis techniques, such as elemental analysis, are used. In one embodiment, the opaque flakes containing indicia such as a particular shape substantially match the visual properties of the bulk pigment, or other material with which they are mixed. In certain embodiments, a single layer of inorganic opaque flakes of a selected shape is mixed with iridescent mica flakes or other base pigments. For illustrative purposes, a “single layer” of inorganic material includes multiple layers of the same inorganic material stacked on top of each other.

  Inorganic covert flakes are particularly desirable in applications where heat, solvent, sunlight, or other factors degrade organic flakes. For example, inorganic covert flakes used in explosives can be detected even after exposure to high temperatures and / or high pressures and are environmentally resistant. Flakes according to embodiments of the present invention are also significantly thinner than conventional shaped flakes, typically less than about 10 microns, so they can be used in inks without the need for a clear overcoat layer. It is possible to create a smooth surface finish of the paint. Thin inorganic flakes according to embodiments of the present invention further have a density close to that of base pigment flakes made using similar techniques. Thick flakes incorporating an organic substrate often differ in density from thin base pigment flakes and may separate before or during application while the carrier is a fluid. When flakes separate, the ratio of the covert flakes to the base flakes in the composition does not match, and as a result of the separation, if the concentration of covert flakes becomes excessively high, the covert nature of the covert flakes may deteriorate. The separation of is not preferred.

II. Exemplary Opaque Flakes FIG. 1 is a plan view of a portion of a document 10 having a security feature 12 according to an embodiment of the present invention. At least a portion 14 of the security feature 12 is printed with an ink or paint that includes opaque flakes having indicia mixed with bulk pigment, such as bulk pigment flakes (hereinafter “confinement flakes”). In one embodiment, the covert flakes have a specific shape, such as a square, rectangle, trapezoid, “diamond”, or circle. In another embodiment, the covert flake includes a lattice pattern with or without a selected shape. Preferably, the selected shape is formed by embossing, etching, or using a laser to create a frame or boundary along which the flakes fracture when removed from the temporary support substrate. In certain embodiments, the grating pattern has a grating spacing that is not optically active in the visible region of the spectrum. That is, these grating patterns do not form a visible diffraction grating. Not all taggent flakes are necessarily covert flakes, but covert flakes are sometimes referred to as taggent flakes.

  In general, bulk pigment particles, including bulk pigment flakes, have an irregular shape. In one embodiment, covert flakes are distinguished from bulk pigment flakes by their shape. Alternatively, the bulk pigment flakes have a selected first shape and the covert flakes have a selected second shape. The production of shaped pigment flakes uses a patterned substrate to deposit the flake material on the substrate and then separates the flakes from the substrate to obtain a pattern such as a frame or border, or the flake material This can be accomplished by a variety of techniques, such as using a laser or other means to cut the patterned flakes from the sheet. The shape of the covert flakes selected may be associated with, for example, the manufacturing equipment, the date of manufacture, or other aspects of the document 10, or the ink for manufacturing the document.

  A roll coater is one type of apparatus that can be used to produce selectively shaped or randomly shaped covert flakes according to embodiments of the present invention. A sheet roll (also known as a “web”) of polymeric substrate material is passed through the deposition zone (s) to coat one or more thin film layers. A roll of polymer substrate may be passed through the deposition zone (s) multiple times. The thin film layer (s) is then separated from the polymer substrate and processed into flakes. Other devices and techniques may be used.

  In general, it is desirable to limit the total thickness of thin film layers (and thus removed) deposited from a roll of polymer film substrate to less than about 10 microns. PET is one type of polymer film substrate used in roll coaters, and the thickness of the PET film substrate is typically at least about 13 microns. If the PET film is thinner, it tends to be thermally deformed during the vacuum deposition process. As the polymer substrate passes through the deposition zone, both the heat in the deposition zone and the condensation heat of the deposited thin film layer (s) increase the temperature of the polymer substrate. Therefore, the minimum thickness of flakes cut from and incorporating a PET film is about 13 microns.

  In addition to flakes of a selected shape that are realized by embossing the frame into a substrate that preferably separates and breaks along with the flakes, the covert flakes are preferably one or more symbols, frames Other forms of indicia and bounded by frames and / or grid patterns are included. The grid pattern is embossed onto a substrate used in a roll coater prior to deposition of a thin film layer that is processed into flakes or otherwise formed. In yet another embodiment, a selected amount (percentage) of the deposition substrate surface area is a lattice pattern to obtain a selected amount of covert flakes when the thin film layer is peeled from the deposition substrate and processed into flakes. Or embossed with a shape pattern. This technique provides covert flakes with the same optical design (thin film layer composition and thickness) as the base flakes. For example, embossing 10% of the deposited substrate surface area with a lattice pattern and / or shape pattern results in a pigment mixture having about 10% covert flakes. FIG. 10 shows a blend of two different optical designs for molded / symbolized flakes and unmolded / flat flakes. Two different optical designs can be implemented in the same vacuum process, but this is not preferred. Preferably, different rolls of deposition substrates with different percentages of embossed surface area are produced to obtain pigment mixtures with different amounts of covert flakes, or in different patterns to obtain different shapes and / or lattice patterns. Embossed.

  FIG. 2A is a simplified diagram of a portion of a deposition substrate 11 having an embossed portion 13 and an unembossed portion 15. The embossed part has an exaggerated frame for illustrative purposes, and alternatively or optionally has, for example, a grid or a symbol, and the unembossed part is essentially smooth. Alternatively, the unembossed portions are embossed with different frames, grids or symbols. Depending on the surface area ratio of the embossed portion 13 to the non-embossed portion 15, a selected amount of taggent having the same thin film structure as the base flake (made from the unembossed portion) (made from the embossed portion) -Flakes are made. While the deposition substrate 11 moves from one roll 17 to another roll 19 through a deposition zone (not shown) in the roll coater, alternative embodiments use different types of substrates and deposition systems. FIG. 2B is a simplified view of a portion of another deposition substrate 11 'having an embossed portion 13' and an unembossed portion 15 '.

  Pigment flakes with identification marks provide security features even if they are easily observable. However, if the pigment flake with the identification mark cannot be easily observed, the counterfeiter may not know that the covert flake is present. One embodiment of the present invention uses covert pigment flakes that have the same optical properties as the base pigment. The covert pigment flakes are not visible to the naked human eye, but become visible when magnified from about 50 to 1000 times. Covered pigment flakes with essentially the same visual characteristics can be mixed with base pigments in a wide range of proportions without significantly affecting the color of the composition. In some embodiments, covert pigment flakes are easily identified with compositions having 95 to 90% by weight base pigment flakes having the same appearance (eg, color and / or color transfer) as 5 to 10% by weight covert pigment flakes. it can. In many cases, the molded opaque covert flakes are easily identifiable in the field using a handheld microscope (eg, a “shirt pocket” microscope), and the same dimensioned flakes with a symbol to identify Requires a lower magnification.

Another approach is to use an opaque covert flake of a selected shape with a different color than the base flake. In one embodiment, opaque covert flakes are bright metal ( "silver") flake having a thin layer of aluminum or other reflector between the dielectric material layer, such as MgF _2. Bright flakes are generally highly reflective over a wide range of visible wavelengths and often do not have a characteristic color. Gold and copper glitter flakes, for example, appear yellowish and reddish. Addition of about 0.25% to about 5% by weight of shaped (eg, “diamond”) glitter flakes in the colored base pigment does not cause a significant change in color, but about 50 × (ie, It has been found that it can be easily identified with an exposure magnification of 50 times magnification. With exposure expansion, the flake shape and high brightness distinguish the flake from the base flake. When less than about 0.25% shaped glitter flakes are used, it is difficult to detect covert flakes as the result of dilution with base flakes is less shaped glitter flakes in the field of view.

  When the amount of bright flakes exceeds about 5% by weight, the color (eg, hue) of certain types of flakes, particularly dark flakes, changes. In such cases, excess bright flakes basically “lighten” the color of the base pigment. However, it is highly desirable to use glitter flakes molded in compositions with color shifting pigments, since a single type of molded glitter flakes can have many different types (color and / or color transfer). This is because only a small amount is added to the pigment flakes, and a relatively small amount of shaped glitter flakes provide a covert security feature. Similarly, in applications where it is not intended to replace a composition containing pigments and glitter flakes with a composition containing 100% pigment flakes or otherwise indistinguishable, it is important that the color fades. is not.

  The pigment is often mixed in the carrier to form a paint or ink. Examples of carriers are polyvinyl alcohol, polyvinyl acetate, polyvinyl pyrrolidone, poly (ethoxyethylene), poly (methoxyethylene), poly (acrylic) acid, poly (acrylamide), poly (oxyethylene), poly (maleic anhydride) , Poly (saccharides) such as hydroxyethylcellulose, cellulose acetate, gum arabic and pectin, poly (acetal) such as polyvinyl butyral, poly (halide) such as polyvinyl chloride and polyvinylene chloride, poly (such as polybutadiene) Diene, poly (alkene) such as polyethylene, poly (acrylate) such as polymethyl acrylate, poly (methacrylate) such as polymethyl methacrylate, poly (oxycarbonyloxyhexamethylene) Poly (carbonate), (poly) esters such as polyethylene terephthalate, poly (urethane), poly (siloxane), poly (sulfide), poly (sulfone), poly (vinyl nitrile), poly (acrylonitrile), poly ( Styrene), poly (phenylene) such as poly (2,5dihydroxy-1,4-phenyleneethylene), poly (amide), natural rubber, formaldehyde resin, other polymers, and polymer mixtures and polymers with solvents. It is.

  FIG. 3A is a simplified plan view of a portion 14A of the security feature 14 shown in FIG. A portion 14A of the security feature is typically about 20 to view the shape of the flakes that are typically about 5 to 100 microns wide, more typically about 20 to 40 microns wide. It is visually observed at a magnification of 300 times. The security feature was printed using ink containing base pigment particles 16 and covert pigment flakes 18 having a selected shape, in this case a “diamond” shape. The optical properties and concentration of the covert pigment flakes are selected so as not to impair the visual appearance of the composition made with the base pigment particles.

  Base pigment particles 16 are illustrated as irregularly shaped flakes. Alternatively, the base pigment flakes have a selected (ie regular) shape. Similarly, the covert pigment flake 18 could have a lattice. By adding a lattice, imitation becomes even more difficult. In some embodiments, the covert pigment flake 18 has approximately the same optical properties as the base pigment particles. Alternatively, the covert pigment flake 18 has different optical properties than the base pigment particles, but in a small enough amount so as not to impair the visual appearance of the composition made with the base pigment particles.

In certain embodiments, “diamond” covert flakes are glitter flakes having a width of about 25 microns × 35 microns. Molded flakes are embossed with a rhombus pattern into a roll of PET-deposited substrate material and then a standard thin film design for bright flakes (eg, about 100 to 60 nm of aluminum between each layer of MgF ₂ with a thickness of about 400 nm) It was made. The total thickness of this bright flake is about 900 nm, or about 1 micron. An embossed pattern (unlike a grating intended to create a pattern in or on a flake), also known as a “frame”, is convex in one embodiment and another implementation It is concave in form. In addition to the diamond-shaped flakes themselves providing some degree of confidentiality features when distributed in a certain proportion with other irregularly shaped flakes, embossing additional confidential symbols on the diamond-shaped flakes Processing results in two levels of covert features that can be used to protect the device.

  Combining the metal layer with one or more dielectric layers facilitates removal of flakes from the deposition substrate. Thin film stacks having only dielectric layers are fragile and often cause residual stresses in the deposition process. Such thin film stacks tend to break more randomly and reduce the number of molded flakes. Because metals are relatively ductile, all metal stacks or monolayers are difficult to process into flakes patterned according to the frame of the deposition substrate body. In certain embodiments, the metal-dielectric and dielectric-metal-dielectric flakes have a total thickness of about 0.5 microns to about 3 microns, providing a good combination of ductile and brittle properties, As a result, good patterning of the flakes is possible when the flakes are removed from the substrate and processed. In certain embodiments, molded glitter flakes having a ductile metal layer with a total thickness of about 1 micron between brittle dielectric layers yielded about 90% rhombus flakes from the embossed deposition substrate.

  The thin film layer was peeled from the deposition substrate using conventional techniques and processed into flakes. The embossed rhombus pattern resulted in lines where the thin film layer broke along it into selected rhomboid flakes. In another embodiment, the diamond-shaped flakes were approximately 12 microns by 16 microns and included a grating on the major surface of the flakes. The grating was nominally 2000 lines / mm and did not produce any diffractive effects in the composition when used as a taggent. The shape of the 12 × 16 micron flakes was easily visible at 100 times magnification. However, the grid was not easily visible with this enlargement. The grid looked easy at 400x magnification. In another embodiment, the grid was coarser and easily visible with the same magnification (eg, 50 to 100 times) used to identify the shape of taggent flakes. Thus, the grating used to provide security features on taggent flakes need not be optically active in the visible portion of the spectrum.

In certain embodiments, the base pigment particles are mica flakes coated with a layer of TiO ₂ or other dielectric material. The coating material typically has a relatively high refractive index. Mica is a naturally occurring mineral that is relatively inexpensive and easy to process into a flake substrate. When the mica flake substrate is coated with a layer of high refractive index material of the selected thickness, nacreous pigment flakes are obtained. The mica flake substrate can be coated with several alternative materials using a variety of processes. Such pigments are generally known as “mica-based” pigments. A copy of an image printed with such a nacreous pigment does not look like the original, and therefore mica-based pigment flakes are desirable for use to provide overt security features. However, it is not practical to form a mica flake substrate or to provide a symbol on the mica flake substrate. Covert flakes according to embodiments of the present invention are mixed with mica-based pigments so that covert security features can be included in images printed with mica-based pigment flakes. Molded pigment flakes made from a single layer of inorganic dielectric material such as TiO ₂ or ZnS have a covert pigment flake that is about five times the optical film thickness (“QWOT”) of a quarter wavelength at wavelengths in the visible spectrum. If it is thick, it will look the same as a mica-based pigment. Typically, the thickness of a single layer ZnS covert flake intended to match the appearance of a mica based pigment is from about 60 nm to about 600 nm. When all dielectric flakes are processed from a deposited substrate having an embossed rhombus pattern, the yield tends to be lower than the counterpart metal-dielectric flakes.

  FIG. 3B is a simplified cross-sectional view of the bright pigment flake 20 according to an embodiment of the present invention. A reflective layer 22 is between the two dielectric thin film layers 24, 26. The dielectric thin film layers 24, 26 provide rigidity to the bright pigment flake 20 and facilitate removal of the pigment flake from the roll coater substrate. To obtain a composition that dries or cures to a smooth surface, it is desirable to keep the thickness of the bright pigment flakes below 10 microns. In certain embodiments, the flake thickness is from about 1 micron to about 3 microns. Thinner flakes are too light and are more difficult to process and handle, and thicker flakes are too strong and tend to break along the frame pattern.

The reflective layer 22 is typically a thin film layer of a highly reflective metal such as aluminum, platinum, gold, silver or copper, or a medium reflective metal such as iron or chromium. The reflective layer 22 is typically thick enough to be opaque (reflective) in the visible portion of the spectrum, but not so thick as to prevent separation of the thin film layer from the substrate and subsequent processing into flakes. In other words, a metal reflective layer that is too thick tends to provide a ductile layer between the relatively fragile dielectric layers 24, 26, which tends to hinder the processing of the deposited layer into flakes. Particularly suitably materials for the dielectric _{layer, ZnS, MgF 2, SiO 2} , Al 2 O 3, TiO 2, Nb 2 O 5, and includes _Ta 2 _{O 5.} In some embodiments, the dielectric thin film layers 24, 26 also provide environmental protection to the reflective layer 22.

  The glitter flake 20 has a selected shape and optionally or alternatively has other indicia such as a surface (lattice) pattern or elemental fingerprint. Brilliant flakes 20 are added to colored pigments and colored compositions (eg, inks and paints) at sufficiently low concentrations. The shaped glitter frame can be added as a covert security feature to the base (ie, randomly shaped or alternately shaped) glitter flakes.

  FIG. 3C is a simplified cross-sectional view of a bright flake 20 ′ having an element indicator layer 28. Bright flake 20 'has reflective layers 22' and 22 "between dielectric layers 24 ', 26' and layer 28 to provide an element indicator. Element indicator layer 28 is a base on which a bright frame is used. Not found in pigments and easily detectable using elemental analysis methods such as secondary ion mass spectrometry (“SIMS”), energy dispersive X-ray (“EDX”), and Auger spectroscopy It is a material layer. In addition, elemental indicators are present in covert flakes but not in base flakes, and micro SIMS, micro EDX or micro-auuge spectroscopy easily detects this difference. Simply adding an indicator element to the pigment mixture (eg, adding a small amount of a compound containing the indicator element to the carrier) does not break this security feature.

  The element indicator layer 28 is not in an optically active state because it is between the two opaque reflective layers 22 'and 22 ". The reflective layers 22', 22" are used in base flakes such as aluminum. Selected to be the same material as that. Suitable materials for elemental indicators include platinum, iridium, osmium, vanadium, cobalt, and tungsten, among others. One skilled in the art will understand that the element indicator material selected will depend on the base pigment with which it is used. In an alternative embodiment, the reflective layer of glitter pigment is made of an element indicator material (see reference numeral 22 in FIG. 3B). For example, covert bright or colored pigment flakes using platinum as the reflective layer are mixed with base bright flakes or colored pigment flakes using aluminum as the reflective layer. In yet another embodiment, the amount of flakes with element indicators incorporated into the pigment mixture or composition is selected to be at a selected element ratio (eg, aluminum to platinum) within the pigment mixture. In an alternative or further embodiment, the material of the dielectric thin film layers 24 ', 26' (reference numbers 24, 26 in FIG. 3B) is selected to provide an elemental indicator.

  FIG. 3D is a schematic cross-sectional view of a color shifting pigment flake 30 according to another embodiment of the present invention. Color-shifting pigment flake 30 is commonly known as a symmetrical five-layer Fabry-Perot interference flake. The thin film stack 32 includes a reflective metal layer 34, two spacer layers 36A and 36B, and two absorption layer bodies 38A and 38B. The absorber layer is typically a very thin translucent layer of chromium, carbon, or other material. The reflector, spacer, and absorber layers are all in an optically active state, i.e. contribute to the optical performance of the color shifted pigment flakes. Both sides of the flake provide the same Fabry-Perot interference structure for incident light, and therefore the flake is optically symmetric. Alternatively, the color shifting pigment flakes are all dielectric pigment flakes or three layer flakes such as absorber / dielectric / absorber.

  The color and color movement of the color-shifting pigment flakes is determined by the optical design of the flakes, ie the material and thickness of the layers in the thin film stack 32, as is well known in the field of optically variable pigments. The optical design of the color shifting pigment flake 30 is typically selected to match the optical properties of the base pigment flake to be mixed. The color shifting pigment flake 30 is molded (see reference numeral 18 in FIG. 3A) and optionally or alternatively includes other indicia such as a surface grid pattern and / or elemental indicator.

For example, the reflective layer includes an elemental indicator that is a reflective metal that is different from the base pigment flake, or includes an additional elemental indicator layer (s) that may or may not be in an optically active state. (See FIG. 3C, reference numeral 28). Alternatively or additionally, spacer layers 36A, 36B and / or absorber layers 38A, 38B include elemental indicators. For example, if the base pigment flake uses MgF ₂ , SiO ₂ , or Al ₂ O ₃ as the spacer layer material, the covert pigment flake 30 uses a different spacer layer material such as TiO ₂ or ZnS. The spacer and / or absorber indicator material contains elements that are easily detected using elemental analysis.

In some embodiments, the use of different spacer and / or reflector materials results in covert pigment flakes 30 that have different optical properties than the base flakes. For example, even if covert flakes and base flakes have the same color at normal incidence, the color shift may be different. In general, low refractive index spacer materials (such as MgF ₂ and SiO ₂ ) have more color transfer (“quick shift” pigments) than high refractive index spacer materials (such as ZnS and TiO ₂ ). However, most of the normal observers cannot detect the difference between the mixture according to an embodiment of the present invention and 100% base flakes, so that the color shift does not exactly match the base flake color shift. However, such covert flakes can be added to the base pigment flakes at a relatively high concentration.

  FIG. 4 is a cross-sectional view of a varnish 40 including covert flakes 42 dispersed in a carrier 44 according to an embodiment of the present invention. The carrier is transparent or colored and the covert flake 42 is at a selected concentration to avoid normal visual detection. An optional color coat or glitter (eg, “chrome plated”) coating 46 is applied to the object 48 under the varnish 40. The varnish 40 provides confidential security features to the object without compromising the appearance of the object. In certain embodiments, the optional color coat 46 is an image printed with nacreous or color-shifting pigments to impart overt security features to the object. The object is for example a document, a product, a package or a seal. The varnish 40 makes it possible to add a covert security feature to an object that already has a covert security feature without significantly impairing the appearance of the object. For example, if an overt security feature is printed on a stock certificate and then it becomes desirable to add a covert security feature to the stock certificate, the varnish 40 or similar ink composition (i.e. covert flakes) is applied to the overt security feature Containing an essentially transparent ink composition). In another embodiment, additional confidential security features are added to objects that already have one or more confidential security features. In certain embodiments, covert flakes account for 2% or less of the varnish.

  FIG. 5 is a cross-sectional view of a composition 50 (eg, ink or paint) comprising base pigment flakes 16 and molded covert flakes 18 dispersed in a binder or carrier 52 according to another embodiment of the present invention. The covert flake 18 has a selected shape or other indicia such as an element indicator or a surface grid pattern. The composition 50 is applied to an object 48 such as a label, product package, bank note, or consumer product.

  By adding covert flakes to existing ink or paint compositions, covert security features are imparted to images made of ink or paint. For example, ink containing a color-shifting pigment is used to impart a color-shifted image as an overt security feature to banknotes or other objects. Covered flakes according to embodiments of the present invention are added to the ink, and the resulting mixture is used to print an image that looks similar to that printed with the original ink. Thus, a regular observer of banknotes is unaware of the change in appearance of the apparent security feature (ie, the color shift image) even after the confidential security feature has been added. The covert flake mark indicates, for example, the date of manufacture, the printing location, and / or the ink distributor (manufacturer).

III. Experimental Results A test standard using 100% magenta-green optically variable intaglio (“OVI”) pigment flakes was produced and measured. Both bright and optically variable taggent samples have a 2000 line / mm grid pattern, which makes taggent flakes easier to distinguish from base pigment flakes (ie position detection). ), Making it more difficult to imitate. The grating pattern was clearly visible at about 400 times and did not produce visible diffraction properties in the image printed with the test composition. It is considered that the fact that the ratio of taggent flakes is low together with the fact that the orientation is not sufficiently oriented to the observer prevents the generation of the diffraction effect. In an alternative embodiment, the shaped taggent flakes include a fine grid pattern. The shape can be identified with a microscope at the first magnification, but the lattice pattern is not easily visible at this first magnification. The lattice pattern is visible with higher magnification. Inclusion of such a lattice pattern in taggent flakes with a selected shape or symbol further enhances the confidential nature of taggent flakes because the imitator visually recognizes the shape or symbol in a microscopic experiment, This is probably because the lattice pattern is not visually recognized and is therefore not included in the imitation.

  The first test sample (“Sample 1”) was mixed with 10% magenta-green OVI pigment flakes (“taggent flakes”) with a lattice (weight ratio) 90% conventional (base) magenta-green. It contained pigment flakes. Taggent flakes were easily detected by routine microscopic examination, and the color reproduction of the mixture was similar to that of the test standard because the color of the taggent flakes matched well with the color of the base flakes. The exact color matching involves careful monitoring of taggent flake production, and a new optical design for each color of the taggent flake will generally be used to match each color of the base flake.

  Another approach is to use a standard taggent flake design that can be used with many different colors of base flakes. Bright taggent flakes using an aluminum reflector layer (which gives the flakes a “silver” appearance) were also evaluated. The production of bright flakes was relatively simple, and these flakes were very easy to detect at a concentration of 5% when mixed with colored base pigment flakes. Bright taggent flakes are used with multicolored base pigments to provide confidential security features. The amount of bright taggent flakes in the composition depends on the desired result. For example, the color reproducibility of an Intaglio blend containing 5% bright taggent flakes mixed with a magenta-green OVI base can be distinguished by comparison with a composition of 100% magenta-green OVI flakes. Compositions that are essentially indistinguishable from 100% magenta-green OVI flakes, such as compositions at concentrations that contain about 0.25 wt.% To 3 wt.% Bright taggent flakes in the magenta-green OVI flakes. Less than 5% bright flakes are used. It is believed that when bright flakes with a concentration of more than 5% are added to pigment flakes, a brighter or less saturated color is obtained without appreciably changing the appearance of the composition. Brilliant taggent flakes are easily detected with moderate magnification even at concentrations below 1%, but it has a selected shape and is of a different color (eg "silver" instead of magenta) It is a combination.

IV. Experimental Method FIG. 6 is a flowchart of a pigment flake manufacturing method 600 according to an embodiment of the present invention. A roll substrate is provided having an unembossed ("flat") portion and an embossed portion at a selected ratio in the deposition surface area of the roll substrate (step 602). In one embodiment, the embossed portion is embossed with a frame to produce flakes having a selected shape. In an alternative embodiment, the embossed portion is embossed with a grid pattern or symbol. In an alternative embodiment, the substrate is patterned using a process other than embossing such as laser ablation. At least one thin film layer is deposited on the roll substrate (step 604), and the deposited thin film layer (s) are processed into flakes (step 606), with flakes having a selected amount of taggent flakes. A mixture is formed. The yield of taggent flakes depends on factors such as the type of thin film layer being processed, the nature of the frame, grid pattern or symbol, and processing parameters.

  For example, referring to FIGS. 2A and 2B, when 10% of the roll substrate surface is embossed with a grid or symbol, a yield of about 10% taggent flakes with a grid pattern or symbol is expected. When 10% of the surface of the roll substrate is embossed with a rhombus frame, about 9% of the dielectric due to 10% yield loss when the patterned portion of the thin film stack is processed into molded flakes -Metal-dielectric flake yield is expected. Similarly, in the case of molded all-dielectric flakes, a yield of about 5% is expected due to a 50% yield loss when the patterned portion of the thin film stack is processed into shaped flakes. .

  Although the invention has been described in connection with various specific embodiments, aspects of the invention will now be described that provide important advantages.

  For example, an embodiment of the present invention that provides significant advantages is the manner in which a frame or boundary is used on the substrate material used to form the coating thereon to enclose the symbols or indicia surrounded by these boundaries. .

記号は周囲にエンボス加工された境界を有している。これは一般に、ＰＥＴ基板のような有機基板にフレームが付けられた

記号をエンボス加工し、その後基板に除去可能なコーティングを被覆することによって達成される。図８は下地もしくは基板から分離した後のフレークの写真である。この写真は僅かな亀裂が記号内に、または記号を貫いて見えているが、ほとんどの記号に損傷がないことを明瞭に示している。本発明を利用することによって、図面中、

記号を不明瞭にするように破損しているフレークは極めて少ない。しかし、図示されているのは、フレークが堆積された基板からフレークを剥離した後はすべてのフレークの全側面に沿ってフレームが存在しないことである。あるフレークには境界がなく、別のフレークには１つから４つの境界がある。しかし、このことは理解できる。フレーム境界はフレークを最も隣接したフレークから分離するので、フレークが分離すると境界は一般に１つのフレークに付着した状態を保つが、そのフレーム境界の反対側では隣接するフレークには付着しない。しかし、フレームまたは境界が存在することで、フレームの一方の側または他方の側のフレーム線上でほとんどのフレークが破損し、比較的真っ直ぐなエッジを有する比較的均一なフレークが得られる。記号を付した各フレークはしばしば、フレークが堆積されたウエブまたは基板から分離した後、フレークに付着した少なくとも１つの境界またはフレームの区分を有している。好ましくは、フレームはフレークの他の部分よりも分離し易い。 Turning now to FIG. 7 and referring to this, there is shown a photograph of a sheet with a number of euro symbols,

The symbol has an embossed border around it. This is generally framed on an organic substrate such as a PET substrate

This is accomplished by embossing the symbol and then coating the substrate with a removable coating. FIG. 8 is a photograph of the flakes after separation from the substrate or substrate. The picture clearly shows that a few cracks are visible in or through the symbol, but most of the symbol is undamaged. By using the present invention,

Very few flakes are broken so as to obscure the symbol. However, what is shown is that there is no frame along all sides of all flakes after flakes are peeled from the substrate on which the flakes are deposited. Some flakes have no boundaries and other flakes have one to four boundaries. But this is understandable. Since the frame boundary separates the flakes from the most adjacent flakes, when the flakes separate, the boundary generally remains attached to one flake, but does not adhere to adjacent flakes on the opposite side of the frame boundary. However, the presence of a frame or boundary causes most of the flakes to break on the frame line on one or the other side of the frame, resulting in a relatively uniform flake with a relatively straight edge. Each flake with a symbol often has at least one boundary or section of frame attached to the flake after it has separated from the web or substrate on which the flake is deposited. Preferably, the frame is easier to separate than other portions of the flakes.

  FIG. 9 is a photograph of a plurality of Mg-Gn flakes with a μ symbol, which flakes are randomly damaged, and are clearly cracked due to stress cracks and the absence of a frame. Hold some symbols, destroy other symbols. FIG. 9 shows that stress cracks throughout the flakes cause the flakes to separate in response to those cracks. In addition, cracks continue to appear in the flakes, thereby obscuring the symbol. The provision of a frame according to the present invention does not completely prevent stress cracking, but it is more probable that these cracks occur along the frame line or preferentially follow a path along it. Providing a means that can be controlled over a wide range. In contrast to FIG. 9, the illustrated embodiment of the present invention associated with FIGS. 7 and 8 allows the flakes to be separated along predetermined boundaries, thereby greatly reducing the shape and completeness of the symbols on the flakes. It shows a mode in which it is preserved to a high degree and does not obscure the secret symbol in the frame as a whole.

  Cracks that occur in symbols that are not surrounded by a frame are generated and propagated in a more brittle glassy dielectric material, but the propagation stops at the frame line provided on the framed symbol sheet shown in FIG. Propagation continues along the path along it. Providing a frame causes preferential rupture of flakes along the frame line. Most of the cracks observed in the flakes of FIG. 8 do not progress through the entire thickness of the flakes to the end, creating a shadow that is detrimental to the reading of the originally embossed symbol (Al / It stops at the level of (Ni / Al).

Both flakes of FIG. 8 and 9 has a thickness is about 1300nm i.e. 1.3 micron, the structure of the layer is Cr of _MgF 2 / 10nm of Al / 480 nm of _MgF 2/80 nm of 10nm of Cr / 480 nm. Ni is included to provide a magnetic layer for the manifest function.

  Turning now to FIG. 10, this is a photograph of a plurality of framed symbols in a larger number of flakes without a covert symbol or frame, the ratio of framed symbols to other flakes being 1:10 is there. There are two interesting aspects to this embodiment. In the first level of detection, the presence of a covert flake with a Euro symbol on it can be detected with a 100 × portable microscope, and the ratio of covert and non-close cover symbols is approximately 1 : 10 can be quickly estimated. Furthermore, a certain degree of authenticity confirmation can be obtained by comparing the ratio between square symbols and randomly shaped flakes. Thus, the shape, distribution and identification of the symbols in the framed shape can be used to determine whether the coating can be trusted with a certain range of certainty.

  Flakes having a symbol surrounded by a border or frame often break to the desired shape along the frame line or groove, as shown by the framed euro in FIG. 10, but the embossed to form the symbol There are examples where flakes break unnecessarily along a line.

  Referring now to FIG. 11a, there is shown a cut-away cross section of the substrate 110 that defines only a portion of the array, more specifically, one complete flake and the other flakes in the vicinity are formed. The substrate relating to the partial area can be seen. In this exemplary embodiment, the bordered or framed flake with the word “JDSU” and the accompanying logo may break along the frame boundary 111 such that the shape of the flake is square. As desired, the depth of the groove 111 forming the border or frame 111 is significantly deeper than the groove forming the logo 112 or text 113. In order to ensure that the flakes break and separate along the frame boundary, i.e. in the frame groove, the depth ratio of the frame to the logo or text is at least 10: 8, more preferably more Is preferred. FIG. 11b is a partial analysis showing the relative depth of the embossment on the substrate. The groove defining the frame is U-shaped and wider than the groove defining the logo and text, which is narrower in V shape. The coating material that covers the substrate and forms flakes is preferably filled more in the text and logo grooves than in the frame grooves. This increases the fragility of the frame and reduces the fragility along the grooves that define the text or logo. FIG. 11c corresponds to FIGS. 11a and 11b and is a normal view of the substrate.

  In contrast to FIG. 11a, FIG. 11d is a mirror-image relief substrate, the frame is defined by a wall, and the text and logo protrude from the bottom of the substrate. FIG. 11e shows the relative height of these walls and FIG. 11f is a normal view of the substrate. Even though the flake sheet is removed from the substrate, the logo and frame are still defined by the walls.

  FIG. 12a is a cross-sectional view of a prior art framed flake, where the grooves defining indicia in the form of letters or logo and the grooves defining the frame are the same depth. A complete double-walled U-shaped frame is shown to show the difference between FIGS. 12a and 12b, but after the flakes are separated from the substrate, the flakes break along the path grooves in the frame, so Typically it will not have a double-walled U-frame. A dotted line is shown to indicate where the flake is expected to break when it is separated from the substrate. However, since the groove depth in FIG. 12a is the same for the groove and the symbol, some flakes may break along the symbol groove. As can be seen in FIG. 12b, the depth of the groove defining the symbol is about ½ the height or depth of the groove defining the frame. That is, the frame is deeper than the symbol. This ensures that most flakes break along the groove in the frame rather than along the groove in the symbol. In general, the ratio of the groove of the frame to the groove of the symbol is preferably at least 3: 2, preferably 4: 2 or more.

  The flakes of FIGS. 12a and 12b are shown as having a uniform coating, and the thickness of the flake is approximately the same at the top, bottom and sidewalls.

  Using the physical vapor deposition (PVD) technique of the coating, i.e. the deposition or sputtering of the material hitting the substrate in a trajectory perpendicular or nearly perpendicular to the substrate results in a deposited layer having the same thickness on the top, bottom and sidewalls . In practice, however, PVD deposition produces atoms that are incident at an oblique angle on the substrate, as shown in FIG. 13b, and these oblique orbits produce anomalies that result in varying thicknesses. If the trajectory is extremely slanted, the groove entrance in the deeper groove will have a thinner coating than the bottom, which is desirable in this example where the purpose is the breaking of flakes along the groove.

  The higher the aspect ratio, the greater the difference between the bottom, top and side walls of the feature. This phenomenon is well known in the manufacture of semiconductor devices having features with high aspect ratios.

  Flakes breakage can occur by different mechanisms.

  Wear is a break caused by the application of parallel forces to the surface of the flakes. Breaking is a breakage due to the application of shear force to the flakes. Compression or impact is breakage due to the application of a force perpendicular to the flake surface. Frequent breakage can be due to a combination of these mechanisms. These mechanisms can occur during flake post-treatment and coating coating processes. For example, material crushing (particle-to-particle interaction and / or wear) may occur during mixing operations in the liquid phase necessary to enhance ink and paint uniformity.

  Breaks due to mechanically induced wear and mechanical shear often occur when flakes are passed through a screen in certain printing applications. An example would be that the flakes in the ink interact with the blade in an anilox system during flexo or gravure printing applications, or in rotating silk screen applications where the ink flakes are pressed into the screen by squeezing. This interaction is similar to that used in a grinding method called "knife milling". In this method, the grinding action is obtained by a rotating assembly that uses a knife or blade to cut the particles.

  Impact milling can be done by high speed mechanical interaction with other flakes or with equipment used in post-treatment and coating.

  Nevertheless, surface irregularities concentrate the load on the flakes, resulting in uneven load distribution.

  Such uneven load distribution is shown in FIG. 14a. Depending on the location of the burst point (region) on the flake, there is a local difference in the applied energy. For example, considering damage due to wear, the shear stress generated at the bottom of the deep feature shown in region 1 is greater than the shear stress at the bottom of the well-known feature shown in region 2 of FIG. 14b. Moreover, as explained above, the microstructure at the bottom of the deep feature is expected to be more brittle than the fine structure of the nominal feature.

  Although the present invention provides a way to promote breakage of flakes along the frame lines rather than along the marking lines or grooves, the embodiments described below provide additional protection against the flakes being broken unnecessarily. In order to prevent this, the flakes are protected after they have been separated from the substrate. FIG. 15 shows the flakes encapsulated in a protective coating.

In this embodiment, the flakes can be coated with a high dielectric constant material such as ZnS, TiO ₂ , SiOx, Al ₂ O ₃ or the like, or the dielectric layer / metal layer multilayer flakes can be easily observed. It can be coated with a translucent material such as sol-gel (SiOx). If the flakes are made of a material with a low refractive index n <1.65 and contain the flakes with a material with a high refractive index, i.e. a material with n greater than or equal to 1.65, it is possible to produce finely structured flakes with dielectric properties. Is possible. This embodiment is essentially an alternating stack of high / low / high and all dielectric layers are molded / symbolized with a covert function and a visual optical effect similar to nacreous pigments. Form flakes.

  Advantageously, the containment process not only increases the durability of the flakes but also adds additional functionality to the microstructured flakes. It is well known that, unlike vacuum deposition techniques (PVD or CVD), sol-gel or other wet chemical containment is not compatible with the surface. For example, it is used in ophthalmic optical coatings to mask scratches or other surface defects during the lens casting process.

  Containment with a non-compliant coating in a wet chemical process tends to fill cavities, such as grooves, in the embossed flakes, resulting in an uneven load on the already brittle areas of the flakes to enhance fracture characteristics Less. In contrast, a conformal coating is a coating that has approximately the same thickness everywhere, regardless of the microstructure of the substrate on which the layer (s) are deposited. Non-compliant coatings, such as wet chemical coatings, tend to fill the microstructure voids and thus “flatten” the flakes. This is very advantageous because it gives the advantage that the flakes are embossed so that the visual effect can be seen, and then the flakes are flattened to maintain or enhance the visual effect.

  The coating of flakes embossed in this way has particular applicability in, for example, “edible flakes” for use in the pharmaceutical and food industries. Many FDA approved materials used for “edible flakes” include dielectric materials such as SiOx, TiOx, AlOx, FeOx. However, it has been discovered that these materials are more brittle than metallic or polymeric materials and, according to the teachings of the present invention, produce more commonly known “edible charms” or “edible flakes”. In doing so, the frame is more fragile than the marks in the flakes, and coating these more brittle flakes with a sol-gel or other protective coating may otherwise occur during post-processing. This is very advantageous because it prevents seed breakage.

Improved fracture properties are also observed in the coating of flakes with a translucent ductile material by the containment method. In this case, the flakes are coated by depositing a soft translucent polymer material in a thin layer under vacuum. One suitable deposition process is so-called plasma polymerization. This step _is SiO 2, TiO ₂ and diamond modified forms of plasma enhanced CVD, such as carbon, SiOxHy, are well known in the coatings of TiOxHy or COxHy. In addition, certain polymers can be physically vapor deposited, or even sputtered, to create the function of a finely-structured intimate taggent and increase durability.

FIG. 6 is a plan view of a portion of a document having a security feature. FIG. 2A is a simplified view of a portion of a deposition substrate having an embossed portion and a non-embossed portion. FIG. 2B is a simplified view of a portion of another deposition substrate 11 ′ having an embossed portion 13 ′ and a non-embossed portion 15. FIG. 2 is a schematic plan view of a portion 14A of the security feature 14 shown in FIG. It is a simplified sectional view of luster pigment flakes. FIG. 6 is a simplified cross-sectional view of a bright flake 20 'that provides an elemental fingerprint. FIG. 4 is a simplified cross-sectional view of a color shifted pigment flake 30 according to another embodiment of the present invention. 2 is a cross-sectional view of a varnish including opaque covert flakes dispersed in a carrier according to an embodiment of the present invention. FIG. FIG. 6 is a cross-sectional view of base flakes and opaque covert flakes dispersed in a binder according to another embodiment of the present invention. It is a flowchart of the manufacturing method of the pigment flakes by embodiment of this invention. FIG. 5 is a photograph of a sheet with a plurality of euro symbols each surrounded by a square frame or border embossed on the substrate. Fig. 4 is a photograph of a plurality of Mg-Gn color-shifted flakes, each labeled with the euro symbol and mostly having all or part of the frame surrounding the symbol. A photograph of multiple symbols of Mg-Gn with μ on the flakes, the flakes are randomly broken, and the resulting fracture line with no frame holds some symbols and other The symbol is destroyed. A photograph of a plurality of framed symbols in a larger number of flakes without a covert symbol or frame, the ratio of framed symbols to other flakes is 1:10. FIG. 11a is a broken isometric view of the embossed substrate showing the depth of the frame grooves in the substrate. FIG. 11b is a partial analysis view of the substrate shown in FIG. 11a. FIG. 11c is a perpendicular view of the substrate of FIG. 11a. FIG. 11d is a broken isometric view of the embossed substrate showing the height of the frame wall and logo wall protruding from the substrate. FIG. 11e is a partial analysis diagram of the substrate shown in FIG. 11d. FIG. 11f is a perpendicular view of the substrate of FIG. 11d. FIG. 12a is a cross-sectional view of a prior art flake with a uniform coating. FIG. 12b is a cross-sectional view of a flake according to the present invention in which the depth of the frame is approximately twice the depth of the symbol. FIG. 13a is a cross-sectional view of a flake according to the present invention in which the coating on the wall is thinner than the coating at the bottom. FIG. 13b is a cross-sectional view of a flake according to the present invention. FIG. 14a is a cross-sectional view of a flake groove where the coating is thicker on the top wall than at the bottom of the groove valley, conveniently assisting the breakage of the flake along the groove. FIG. 14b is an illustration of a groove defining a flake symbol showing a uniform coating thickness. FIG. 3 shows a flake according to the present invention in which the flake is encapsulated in a light transmissive protective coating.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Document 11 Deposited substrate 12 Security feature 13, 13 'Embossed part 14 Security feature 14A Part of security feature 15, 15' Non-embossed part 16 Base pigment particle, base pigment flake 17 Roll 18 Covered pigment flake 19 Roll 20, 20 'Bright pigment flake 22, 22', 22 "Reflective layer 24, 24 'Dielectric thin film layer 26, 26' Dielectric thin film layer 28 Element indicator layer 30 Color shift pigment flake 32 Thin film stack 34 Reflective metal layer 36A 36B Spacer layer 38A, 38B Absorber layer 40 Varnish 42 Covered flake 44 Carrier 46 Bright coating 48 Object 50 Composition 52 Carrier 110 Substrate 111 Frame 112 Logo 113 Text

Claims (20)

A plurality of pigment taggent flakes, each flake comprising a peripheral frame defined by a wall and a region within the frame, wherein at least one height of the frame wall is at least a height F _h. The region in the frame has indicia defined by one or more grooves formed therein, the grooves having a depth less than I _d , and the one or more Ri F _{h> I} d ₊ T _f der when the thickness of the flakes at the bottom of the groove was set to T _f, the one or more grooves defining the indicia complementary raised areas on the opposite side of said flakes Multiple pigment flakes to form .   The plurality of claim 1, wherein each flake has a substantially flat upper surface, the wall extends downwardly from the flat surface, and the one or more grooves extend downwardly. Pigment flakes.   The plurality of pigment flakes according to claim 1, wherein the mark is a symbol or a logo.   The plurality of pigment flakes of claim 1, wherein each flake has the same symbol or logo. The plurality of pigment flakes of claim 1, wherein the F _h / _Id is at least 1.5.   The plurality of pigment flakes of claim 1, wherein each flake is encapsulated in a coating.   The plurality of pigment flakes of claim 6, wherein the coating is selected from the group of metals, metal compounds, oxides, nitrides, polymers and cermets.   The plurality of pigment flakes of claim 1, wherein the one or more grooves are V-shaped grooves.   The plurality of pigment flakes of claim 1, wherein the one or more grooves are U-shaped grooves.   The plurality of pigment flakes according to claim 1, wherein the mark is visible only by enlargement.   The plurality of pigment flakes of claim 2, wherein each flake comprises a multilayer coating for providing a visible optical effect. A taggent region sheet for forming taggent flakes,
Depth Saga a substrate that is embossed with a groove of a plurality of indicia in each frame groove is F _h frame, the depth of the groove of the mark at the bottom of the groove of and the indicia than I _d F _h > I _d + T _f when the flake thickness is T _f, and the groove in the mark forms a complementary raised region on the opposite side of the flake, whereby the coating on the sheet is Once separated into taggent flakes, sheets taggent region comprising the likely board corruption along the frame groove occurs than along the groove of the indicia. The frame groove of the cross-section sheet taggent regions as defined in claim 12 that have a different profile than the cross-section of the groove of said indicia.   14. The taggent region sheet according to claim 13, wherein one of the frame groove and the mark groove is tapered, and the other of the frame groove and the mark groove has parallel side walls.   13. A sheet in a taggent region according to claim 12, wherein the sheet comprises a web coated with a coating and the taggent flakes are formed from the coating. A plurality of pigment taggent flakes, each flake comprising at least two side frames defined by walls and a region within the frame, wherein at least one height of the frame walls is at least height F _h , wherein the region in the frame has a mark defined by one or more grooves formed therein, the grooves having a depth less than I _d , the one or the thickness of the flakes in the bottom of the plurality of grooves Ri F _{h> I} d ₊ T _f der when the T _f, the one or more grooves defining the indicia complementary ridge on the opposite side of said flakes A plurality of pigment flakes forming a region .   The plurality of pigment taggent flakes of claim 1, wherein the flakes are coated with a non-compliant coating that reduces the depth of the grooves, and the indicia is not obscured by the coating.   The plurality of pigment taggent flakes of claim 17, wherein the non-compliant coating increases the contrast between the indicia and the background, thereby making the indicia more visible.   The plurality of pigment taggent flakes of claim 17, wherein the pigment taggent flakes are edible flakes. A foil comprising a substrate having one or more thinly deposited thin film layers that form taggent flakes once removed from the substrate, wherein the one or more thin film layers have grooves. Having a plurality of framed symbols to form, wherein the frame of symbols provides grooves for the flakes that separate along removal of the one or more thin film layers from the substrate. , said frame have a deeper groove than the sum of the thickness of the bottom the flakes of the groove of the groove depth and the symbols of the symbol, the groove of the symbols complementary raised areas on the opposite side of said flakes Foil to form .

Images