This disclosure relates generally to optical security features that may be useful to authenticate items such as documents, identification cards, monetary currency, etc., and/or to thwart passing off of counterfeit goods.
The prevalence of counterfeit products and documents is a known problem. The use of inexpensive, high quality color copiers, printers and scanners, as well as other reproduction techniques, have enabled counterfeiters to reproduce the authentication features of many items. In addition, the prevalence of low-cost, simple hologram origination has greatly reduced the value of holograms as a security feature. Because of these advancements, currency, security labels, and identification documentation have been subject to counterfeiting using similar technologies.
Items that may be the subject of attempted counterfeiting include certain types of documents (e.g., passports, identification cards, drivers' licenses, currency, title documents, etc.) and certain consumer goods (e.g., “knock-offs” of brand name items). If a document is to be protected from counterfeiting by using a security laminate, coating or covering a portion of the document for example, the laminate should allow the contents of the document to be seen through the laminate. The security laminate should also be difficult to copy. In addition, security labels used for brand protection and warranty fraud prevention must be relatively simple or easy to authenticate (e.g., preferably without requiring the use of specific tools or equipment) and difficult to replicate or simulate.
Examples of technologies used in this space to protect from counterfeiting include holograms, color-shifting inks and foils, and floating images and other micro-optics features. However, all these features have limitations in either ease of simulation/replication, difficulty of authentication, or complex, expensive manufacturing processes. Embossing is another technique that has been employed to modify and/or enhance the appearance of certain security documents. For example, embossments have been described as a way to provide additional security to security films such as colored mirror films (“CMF”) due to the different color shifts that may be observed where there are embossments. Most commercially available CMF products consist of alternating layers of polymers that provide a certain set of optical properties, and these can have value in security documents as CMF can feature color-shifting properties. The CMF embossing process has typically involved compressing certain regions of the CMF so that the color and color-shift of the film is locally changed because the layer thickness distribution is locally different, meaning CMF is thermally and visually deformable. For example, in U.S. Pat. No. 6,045,894, the embossing examples were performed with metal tooling at high temperatures and high pressure in an extra embossing process using male/female, male only, and female only dies. Using hard, immobile tooling provides embossments that mirror the tooling. This type of embossing process generated embossments with significantly thinner cross-sections (between 5 and 85%) than the rest of the film, which generates a different color-shift. However, this type of embossing process comes with significant complications, challenges, and/or costs.
While certain regions of the embossed CMF may have thinner regions when using embossing processes described in the prior art, there are also thicker regions due to displacement. This non-uniform thickness can cause challenges in converting, printing, die-cutting, coating, and other web-handling processes. In addition, when these features are later incorporated into fused documents such as fused PC documents, the embossments are typically affected (e.g., flattened) by the fused document lamination process, which often use temperatures and pressures on the order of the initial metal-tooling embossing conditions described in the art. Therefore, typically a thick, cushioning adhesive is needed to protect the CMF or other films and embossments from the document fusing process. Some security films may also delaminate, crack, or flake if not supported, especially those with metal or vacuum coatings.
There is an ongoing need for relatively inexpensive security features that are simple to authenticate (for example, by simple tilting or rotating of the feature) and simple to manufacture, yet difficult to simulate or replicate.
This disclosure describes an authentication device (which could be used in a security document, for example) comprising a visually deformable layer disposed between two polymer layers that are fused together by heating, thereby yielding an embossed appearance to the visually deformable layer. In some embodiments, a shaped cutout area in one of the layers may facilitate forming the embossed appearance in the visually deformable layer. In other embodiments, a shaped “chad” (e.g., a portion removed or cut out from a layer of material) may facilitate forming the embossed appearance in the visually deformable layer.
In some embodiments of this disclosure, an authentication device may comprise an upper layer, a middle layer, and a lower layer. The upper layer may comprise a non-opaque polymer film layer having a shaped cutout area, the middle layer may comprise a visually deformable layer sized to at least partially cover the shaped cutout area of the upper layer, and the lower layer may comprise a polymer film layer, wherein the upper and lower layers are both sized to cover the middle layer according to various embodiments. The authentication device may then be formed by positioning the middle layer between the upper and lower layers and adjacent thereto, with the middle layer positioned to at least partially cover the shaped cutout area. The upper and lower layers may then be fused together by exposing the layers (e.g., at least the upper and lower layers) to a temperature that is high enough to fuse the upper and lower layers together, with the middle layer (which includes the visually deformable layer as well) sandwiched in between the upper and lower layers. In some embodiments, this may involve exposing at least the upper and lower layers to a temperature (a “fusion” temperature) that is higher than the glass transition temperature of at least one of the two outer layers (e.g., the upper and lower layers); in some embodiments, the fusion temperature will exceed the glass transition temperature of both the upper layer and the lower layer. During this high temperature fusion, the visually deformable layer will be permanently changed and presents novel optical properties along the edge of the cutout, which also gets deformed during the fusion in a way that mirrors the visually deformable layer deformations. In some embodiments, the overall thickness of the lower layer (which may be comprised of more than one polymer film layer) may be greater than the overall thickness of the upper layer (which may be comprised of one or more non-opaque polymer film layers in addition to the non-opaque polymer film layer having the shaped cutout area, which is disposed adjacent to the middle layer).
In some embodiments of this disclosure, an authentication device may comprise a multilayer structure including a first layer comprising a first non-opaque polymer film layer, a shaped chad layer comprising a polymer film forming a shaped chad, a second layer comprising a visually deformable layer, and a third layer comprising a third polymer film layer. In some embodiments, the second layer (including the visually deformable layer) has an edge boundary sized to at least partially cover the shaped chad, and the first and third layers are both sized to cover the second layer. In some embodiments, the third layer has a thickness that is greater than the thickness of the first layer. In various embodiments, the authentication device is formed by positioning the shaped chad layer adjacent the second layer so that the second layer edge boundary at least partially covers the shaped chad layer. The first layer is positioned adjacent the shaped chad layer, the third layer is positioned adjacent the second layer, and the first and third layers are exposed to a temperature (e.g., a fusion temperature) that is higher than the glass transition temperature of either the first layer or the third layer, or possibly higher than the glass transition temperature of both the first and third layers. During this high temperature fusion, the visually deformable layer will be permanently changed and presents novel optical properties along the edge of the chad, which also gets deformed during the fusion in a way that mirrors the visually deformable layer deformations.
In some embodiments of this disclosure, a method of manufacturing an authentication device may comprise forming a multilayer structure by providing an upper layer comprising a first non-opaque polymer film layer having a shaped cutout area, providing a middle layer comprising a visually deformable layer, providing a lower layer comprising a second polymer film layer, positioning the middle layer between the upper and lower layers so that the middle layer at least partially covers the shaped cutout area of the upper layer, and heating to a temperature sufficient to fuse the upper and lower layers together (e.g., above the glass transition temperature of at least one or the other of the upper and lower layers). In some embodiments, the fusing process results in deformation of the visually deformable layer of the middle layer to produce an embossed appearance and/or other noticeable optical effects.
In some embodiments of this disclosure, a method of manufacturing an authentication device may comprise forming a multilayer structure by providing a first layer comprising a first non-opaque polymer film layer, providing a shaped chad layer comprising a polymer film forming a shaped chad, providing a second layer comprising a visually deformable layer, providing a third layer comprising a third polymer film layer, positioning the shaped chad layer and the second layer adjacent one another with the second layer at least partially covering the shaped chad, positioning the first layer adjacent the shaped chad layer, and positioning the third layer adjacent the second layer, with each of the first and third layers sized to cover the second layer. The authentication device is then formed by heating to a temperature sufficient to fuse the first and third layers together (e.g., above the glass transition temperature of at least one or the other of the first and third layers). In some embodiments, the fusing process results in deformation of the visually deformable layer of the second layer to produce an embossed appearance and/or other noticeable optical effects.
This disclosure describes an authentication device or security feature (which could be used in a security document, for example) comprising a visually deformable layer disposed between polymer layers that are fused together, thereby yielding an embossed appearance to the visually deformable layer. In some embodiments, a shaped cutout area in one of the layers may facilitate forming the embossed appearance in the visually deformable layer upon fusing. In some embodiments, a shaped “chad” in one of the layers may facilitate forming the embossed appearance in the visually deformable layer upon fusing.
In the example shown in
In some embodiments, the first non-opaque polymer film layer may comprise a transparent polymer film layer. In some embodiments, one or more of the additional non-opaque polymer film layers may comprise a transparent polymer film layer. It should be noted that the use of the term “non-opaque” throughout this disclosure is meant to describe a wide range in the amount of light transmission through a layer, from “almost opaque” to fully transparent, and everything in between.
Middle layer 20 of authentication device 4 comprises a “visually deformable layer.” The visually deformable layer is constructed to generate an optical artifact when embossed, which may cause a localized thinning or shape such that shadows may be formed. Preferably, the visually deformable layer will be thermally deformed during the embossing process, which means the visually deformable layer preferably contains at least one polymer component with a glass transition temperature similar to or slightly below the fusion temperature, making it a thermally deformable layer at the temperature of fusion. The visually deformable layer may be colored by dye or structure, such as diffraction gratings or similar technologies known to those in the art. In a preferred example, the visually deformable layer may be comprised of a colored mirror film (“CMF”), according to various embodiments. As used herein, a CMF film comprises a multilayer optical film that extends from a first major surface to a second major surface (e.g., across its thickness), the multilayer optical film made up of alternating first and second optical polymeric layers, wherein each of the first optical polymeric layers has a first refractive index, and wherein each of the second optical polymeric layers has a second refractive index different from the first refractive index. The visually deformable layer may also be a polymer layer with a thin layer of metal deposited on the surface (e.g., vapor-deposited metal). The metal of this deposition could be silver, aluminum, gold, copper, or any other metal that can applied in a layer thin enough to be deformable during the fusion/embossing operation of this disclosure. As the metal layer is deformed and bent by the deformation process, the metal interacts with light differently as a 3D image is formed by shadows in a way similar to other metal embossing effects. Other visually deformable layers are also possible, such as pigmented, patterned, or printed films, films with diffractive elements or coatings, paper or other opaque films, etc. The middle layer 20 has a thickness (e.g., a “second thickness”) and extends across an area (a “middle layer area,” the size of which is indicated by dashed lines) sized to at least partially cover the shaped cutout area 11, as is depicted in
Lower layer 30 of authentication device 4 comprises a polymer film layer (a “second polymer film layer”). Lower layer 30 extends across an area (a “lower layer area”) and has a thickness (a “third thickness”), which may be equal to or greater than the first thickness of the upper layer 10. In some embodiments, both the upper layer area and the lower layer area are sized and/or positioned to cover the middle layer area, as in the example shown in
The authentication device 4 may be formed by positioning the various layers as described and shown, then heating to cause certain layers to fuse together. For example, the “top” side (“second side”) of middle layer 20 may be positioned adjacent the “bottom” side (“first side”) of the first non-opaque polymer film layer of the upper layer 10 to at least partially cover the shaped cutout area 11. (NOTE: For consistency throughout this disclosure, the “first side” of a given layer will refer to the “bottom” side of that layer, and the “second side” will refer to the “top” side of that layer, as the various embodiments are shown and described herein.) The bottom side (first side) of the middle layer 20 may be positioned adjacent the top side (second side) of the lower layer 30 (e.g., adjacent the second polymer film layer of the lower layer 30). It should be noted that the order of performing the positioning steps is not important; the order may be altered and/or reversed, for example. Once the layers are positioned as described above, at least the upper layer 10 and the lower layer 30 are exposed to a temperature (a “fusion temperature”) that results in the upper layer 10 and lower layer 30 fusing together. In various embodiments, the fusion temperature to which the layers are exposed is greater than the “glass transition temperature,” or “Tg,” of at least one of the upper layer 10 and the lower layer 30. In some cases, for example, it may be desirable to raise the temperature above the Tg of both the upper and lower layers 10, 30. In other cases, it may be desirable to raise the temperature above the Tg of only one of the layers 10, 30.
When the fusing of the upper and lower layers 10, 30 is complete, the visually deformable layer (of middle layer 20) may deform to thereby generate an optical effect for authentication device 4. In various embodiments, the visually deformable layer may deform along a boundary of the shaped cutout area thereby creating an optical effect resembling an embossment. This embossing effect may be caused by the heat and/or pressure of the fusing process locally bending and modifying the visually deformable layer near the edges of the shaped cutout area as the polymer material around the cutout area softens over a period of time, which may range from multiple seconds to several minutes, according to some embodiments. Raising the temperature above the Tg of at least one of the upper and lower layers 10, 30 may cause the affected layer(s) to become rubbery and flow; however, unexpectedly, the affected layer(s) may still retain enough mechanical integrity to emboss (e.g., cause deformation to) the middle layer 20. In order to facilitate the affected polymer layers becoming rubbery when heated to the fusion temperature (and not becoming a low-viscosity fluid), the fusion temperature employed should be limited to less than about 80 C above the Tg of the polymer layer(s), and preferably less than 40 C above the Tg of the polymer layer(s). In some embodiments, the visually deformable layer could be embedded within one of the layers of the authentication device 4 (e.g., within the second polymer film layer of the lower layer 30, for example). An example of a visually deformable layer that has been embossed using this process is provided in
The authentication device 104 of
For example, the authentication device 104 of
In certain alternate embodiments, at least one of the first non-opaque polymer film layer 110 and the one or more additional non-opaque polymer film layers 112, 114, 116 of the upper layer 100 may be formed of a material selected from the group consisting of polycarbonate, polyvinyl chloride (“PVC”), and polyester, and/or other non-opaque materials used in secure document construction, for example. In
The authentication device 104 depicted in
The authentication device 104 depicted in
It should be noted that a further alternate embodiment may be formed, which resembles the configuration shown in
With further reference to
Unlike embossing operations of security films described in the prior art, these embossments are formed in situ. This provides manufacturing advantages over pre-embossing as it requires fewer manufacturing operations. In addition, while pre-embossed foils can become modified during the fusing operations of standard security document manufacture, in situ embossments may tend to remain more sharp and/or more clearly defined. In addition, there are security benefits to this embossing process. For example, if an attempt is made to harvest the visually deformable layer 120 in
As upper layer 100 and lower layer 300 of the security document or authentication device 104 shown in
In addition, the embossed visually deformable layer 120 shown in
With further reference to
If this construction were formed in a window, the region of the CMF exposed during laser imaging would feature interesting transmission vs. reflection optics. A CMF that has been pre-embossed using traditional embossing techniques known and described in the art would be difficult to print or coat; by contrast, the technique described herein would enable the use of laser-imagable, embossed CMF with significantly easier manufacturing. The CMF, for example, could be embedded within a layer of a document or device, or could be disposed on the surface of the document or device, etc., according to various embodiments. Another embodiment could involve the use of a CMF as part of middle layer 200 that is also laser-responsive, such as that described in US 2011/0255167. In some embodiments, a vapor-coated metal layer may be employed rather than the CMF. Yet another embodiment similar to the ones shown in
It should be noted that the various embodiments of the authentication devices 4, 104, 204, etc., disclosed herein may be formed as a stand-alone component, or in a card (ID card, credit card, etc.), or incorporated within or as part of a security identification document, or as part of other types of documents, etc.
With continued reference to the authentication device 204 of
The authentication device 204 of
With reference to
Additionally and/or optionally, the first non-opaque polymer film layer 412 and/or one or more of the additional non-opaque polymer film layers 414, 416 of the upper layer 400 may be formed of a material selected from the group consisting of polycarbonate, polyvinyl chloride (“PVC”), and polyester, and/or other non-opaque materials used in secure document construction, according to various embodiments. The third layer 600 may, in some embodiments, comprise one or more additional polymer film layers (e.g., layers 632, 634, 636, and 638) disposed adjacent the first side of the third polymer film layer 630 of the third layer. In some embodiments, the third polymer film layer 630 and/or the additional polymer film layers (e.g., layers 632, 634, 636, and 638) of third layer 600 may further comprise a security feature, such as a print, hologram, and/or a color-shifting foil. Additionally and/or optionally, the third polymer film layer 630 and the one or more additional polymer film layers 632, 634, 636, and 638 of the third layer 600 may be formed of a material selected from the group consisting of polycarbonate, polyvinyl chloride (“PVC”), polyester, and Teslin® or other waterproof synthetic printing medium, and/or other materials used in secure document construction, such as paper or adhesives. Authentication device 204 may, for example, be included as part of or within a security identification document according to certain further embodiments of this disclosure.
Some embodiments of this disclosure include incorporation into or onto a security document. Security documents may include, for example, passports, identification cards, drivers' licenses, credit cards, currency, title documents, stock, marriage, or birth certificates, and security, warranty/fraud detection, or brand and asset protection labels among other security documents. The following examples are provided to help describe how the concepts disclosed hereinabove may be applied in a number of different applications. The examples are intended to be illustrative only and are not intended to limit the scope of the accompanying claims.
Example 1: “Blaze” colored mirror film (“CMF”), made by the 3M Company, is a color-shifting reflective film that appears to be cyan in transmission and red in reflection, which changes when tilted to certain angles to magenta in transmission and yellow in reflection. Blaze film is approximately 30 microns thick. Unembossed Blaze film was coated with an adhesive and converted into 19 mm oval pieces. One oval was adhered to a sheet of Rowland PC (polycarbonate) film that was 180 microns thick. Another sheet of 100-micron Rowland PC film had two 5 mm stars cut out of the PC. The cut-out sheet was placed adjacent to the CMF sheet and other 100-micron PC sheets were added to the stack so that a final thickness of approximately 762 microns (not including the oval inlay) was achieved in a construction similar to what is represented in
This lamination process resulted in fusing of the PC layers together. The shaped cut-out had apparently been filled in by the security film (e.g., the Blaze CMF film) and by the polymer material from adjacent layers as other PC flowed into the cut-out area in a manner similar to what is represented in
In a slight variation of the above method, the same construction and conditions of Example 1 (above) were performed except that no adhesive was used so that the CMF film could be removed after the lamination process in order to measure the thickness of the PC above and below the embossment. The resulting optical effect was the same as in Example 1, and the embossed CMF was indelibly marked. After cutting apart the fused card, the thickness of the PC on the side of the cut-out (e.g., above the cutout, as shown as the region above section 2c in FIG. 2E) was 574 microns immediately above where the cut-out was and was 602 microns away from the embossment area (e.g., the region above sections 2a/2e in
In another example similar to the one formed and described above with respect to Example 1, a fused sample was generated with the following modifications. The “Blaze” colored mirror film (“CMF”), made by the 3M Company was replaced in this sample with a 1.0 mil polyester film that had been vacuum coated with a reflective aluminum layer, and which had no adhesive. The aluminized polyester deformable layer was approximately 14 mm in diameter. The 4.0 mil PC sheet had one cut out star approximately 7 mm across. The resulting fused laminate included a single star embossed according similarly to
Example 2: Another fused sample similar to that formed in Example 1 was made except that the construction did not feature any shaped cut-out areas. Instead, the star-shaped materials that were cut out of the layers of Example 1 (e.g., star-shaped “chads”) were placed to form a small chad layer adjacent to the CMF layer for Example 2. This can be seen in the layered construction shown in the left image of
Example 3: Unembossed Blaze CMF film was coated with an adhesive and converted into 19 mm oval pieces. One oval was placed onto a polyvinyl chloride (“PVC”) film that was 63.5 microns thick. Another sheet of 63.5-micron PVC film had two 5 mm stars cut out of it. The cut-out sheet was placed adjacent to the CMF oval and other PVC sheets were added to the stack so that a final thickness of approximately 762 microns (not including the CMF) was achieved. This stack was then laminated in an OASYS OLA6E press using the following process steps and corresponding conditions:
After the lamination process using the steps and conditions of Table 2 above, the PVC was fused together. The cut-out area had apparently been filled in by the security film (e.g., the Blaze CMF) and polymer from adjacent layers as the CMF inlay was pushed through the star-shaped opening by the PVC below it. Some PVC in the cutout layer and potentially above it also flowed into the cut-out area smoothing out the edges slightly in a manner similar to that represented in
Example 4: Another fused sample similar to that formed in Example 1 was generated, except in this case, the sheet containing the cut-out area was a sheet of 50 micron PET that had been laser imaged with a 5 mm eagle using a UV laser. The laser settings were adjusted so that the PET was locally melted, causing a raised, textured eagle image. During lamination, the eagle embossed the CMF.
Example 5: Another fused sample similar to that formed in Example 1 was generated except only using clear PC and Blaze CMF film that had first been printed with a 2 mm wide black rectangle across its width using UV flexography. The CMF was visually embossed as in Example 1, although the embossment effect was very difficult to see in areas where the ink had been printed. A UV laser was then used to image/etch the black ink in the fused document with the number “76,” ablating the ink away and leaving the underlying CMF film exposed. The CMF color did not seem affected significantly by the laser imaging. As the fused sample used clear PC, the laser imaged area presented interesting optics in that, when it was placed over a white background, the “76” etched pattern appeared to be cyan in color (i.e., the transmitted color), but when it was placed over a black background, the “76” pattern appeared to be red in color (i.e., the reflected color). This was also true when a white light source was placed behind the sample formed in Example 5, generating a cyan color (i.e., the transmitted color). An iPhone with a half black/half white picture on the view screen was placed behind Example 5, and the “76” pattern appeared to be cyan over the white image and red over the black image. In addition, the embossment effect appeared in different colors when placed over the white and black regions of the iPhone picture, providing an interesting authentication technique.
In a variation of Example 5, another sample was made where the Blaze CMF was first coated with a thin layer of aluminum instead of printed. This variation performed in a manner similar to Example 5.
Example 6: Another fused sample similar to the one formed in Example 1 was generated, except the cut-out sheet was a 4 mil PC sheet that was sent through the lamination process while placed against a silicone lamination mat that had an array of raised features approximately 0.8 mm×1.0 mm and separated by about 1.3 mm in the short direction and 1.7 mm in the long direction, respectively. The embossed PC sheet had pockets that were approximately 0.8 mm×0.9 mm at the same spacing as the mat. The resulting embossment in the Blaze CMF film appeared as raised hemispheroids at the same spacing. Since the embossed PC sheet covered essentially the whole fused sample, a white layer (7 mil PC) adjacent to the inlay was also embossed as well. This created a unique effect on the white layer which is not necessarily evident without sidelighting. Thus, this may provide another useful and/or convenient authentication technique.
Example 7: A fused sample was created similar to the one formed in Example 6, except that the white layer was replaced with a printed layer. The resulting embossments also occurred on the printed layer and formed the same pattern on the printed layer as on the CMF film.
Various examples have been described. These and other variations that would be apparent to those of ordinary skill in this field are within the scope of this disclosure.
This application claims priority to U.S. Provisional Patent Application No. 63/331,353, filed Apr. 15, 2022, the entire contents of which are incorporated herein by reference.
Number | Date | Country | |
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63331353 | Apr 2022 | US |