Identification document having a complex window with watermark effect

Abstract

An identification document comprising a substrate (5), a transparent window (10), a layer of opaque material (15), a first image (20) and a second image (25). The transparent window (10) is provided in the substrate (5) such that it extends from the frontside (FS) to the backside (BS) of the substrate (5). The layer of opaque material (15) is at least partly positioned in the transparent window (10). The first image (20) is positioned in the transparent window (10) between the layer of opaque material (15) and the frontside (FS) of the substrate (5). The second image (25) is positioned in the transparent window (10) between the layer of opaque material (15) and the backside (BS) of the substrate (5). In front view of the substrate (5), only the first image (20) is visible when viewed by reflected light and both, the first and second images (20, 25) are at least partly visible when viewed by transmitted light. In back view of the substrate (5), only the second image (25) is visible when viewed by reflected light and both, the second and first images (25, 20) are visible when viewed by transmitted light.

Description

Technical Field

[0001] The present disclosure generally relates to identification documents. In particular, the present disclosure relates to identification documents having a complex window with watermark effect.Background

[0002] Identification documents are used on a daily basis for a number of different purposes. Identification documents are most commonly used to prove identity, to verify age, to access an asset (e.g., secure area, financial account, computing resource, etc.), to evidence driving privileges, to cash a check, and so on.

[0003] For the purposes of this disclosure, identification documents are broadly defined and may include, for example, credit cards, bank cards, phone cards, passports, driver's licenses, network access cards, employee badges, debit cards, security cards, visas, immigration documentation, national ID cards, citizenship cards, social security cards, security badges, certificates, identification cards, voter registration cards, police ID cards, border crossing cards, legal instruments or documentation, security clearance badges and cards, gun permits, gift certificates or cards, labels or product packaging, membership cards or badges, etc. Identification documents may sometimes be interchangeably referred to as "security documents", "ID documents", "credential documents", "security credentials", "photo- IDs", and "photo ID documents".

[0004] Identification documents typically are provided with security features which are directed to verifying the authenticity of the document.

[0005] One known security feature or at least part of a known security feature is a transparent window. A transparent window is a transparent portion provided in the (otherwise opaque) substrate. By means of a transparent window, it is possible to reveal what is positioned in or behind (underneath) the transparent window. A transparent window may be a "fully transparent window" which extends from one side of the substrate (such as the substrate's frontside) to the opposite side of the substrate (such as the substrate's backside), i.e., extends through the entire substrate.

[0006] Transparent windows are a strong security features of an identity document. Transparent windows may be secured by adding additional security features inside the window itself. Security features as disclosed in EP 3077216 . (B1) may be given as an example.

[0007] The present disclosure is directed, at least in part, to provide an improved security feature of an identification document.Summary of the Disclosure

[0008] According to the present disclosure, an identification document has a substrate, a transparent window, a layer of opaque material, a first image and a second image. The substrate has a frontside and a backside opposite to the frontside in a thickness direction. The transparent window is provided in the substrate such that it extends from the frontside to the backside of the substrate. The layer of opaque material is at least partly positioned in the transparent window. The first image is positioned in the transparent window between the layer of opaque material and the frontside such that it at least partly overlaps with the layer of opaque material in thickness direction. The second image is positioned in the transparent window between the layer of opaque material and the backside such that it at least partly overlaps with the layer of opaque material in thickness direction. In front view, only the first image is visible when viewed by reflected light and both, the first and second images are at least partly visible when viewed by transmitted light. In back view, only the second image is visible when viewed by reflected light and both the second and first images are visible when viewed by transmitted light.

[0009] Other features and aspects of the present disclosure will be apparent from the following description and the accompanying drawings.Brief Description of the Drawings

[0010] Fig. 1 shows a sectional view of an exemplary embodiment of the identification document. Fig. 2 I-IV show the exemplary embodiment of Fig. 1 in front view and back view of the substrate as well as in reflected light and in transmitted light. Fig. 3 I-II show a further exemplary embodiment in front view in reflected light and in transmitted light. The *colors of the layer of opaque material and of the background portion is the same. Fig. 4 I-II show a further exemplary embodiment in front view in reflected light and in transmitted light. The opacities of the layer of opaque material and of the background portion are different. Fig. 5 I-II show a further exemplary embodiment in front view in reflected light and in transmitted light. The frontside of the substrate has a third image. Fig. 6 I-II show a further exemplary embodiment in front view in reflected light and in transmitted light. The layer of opaque material has a transparent section and the first and second image are positioned entirely next to each other. Detailed Description

[0011] The following is a detailed description of exemplary embodiments of the present disclosure. The exemplary embodiments described herein are intended to teach the principles of the present disclosure, enabling those of ordinary skill in the art to implement and use the present disclosure in many different environments and for many different applications. Therefore, the exemplary embodiments are not intended to be, and should not be considered as, a limiting description of the scope of protection. Rather, the scope of protection shall be defined by the appended claims.

[0012] The present disclosure is based at least in part on the realization that a layer of opaque material may be positioned in a transparent window of a substrate between a first image and a second image such that the layer of opaque material has a barrier effect (visibility barrier effect) when the frontside or backside of the substrate is viewed by reflected light.

[0013] Further, it has been realized that a layer of opaque material may be positioned in a transparent window of a substrate between a first image and a second image such that the second image has a watermark effect on the first image when the frontside of the substrate is viewed by transmitted light, and the first image has a watermark effect on the second image when the backside of the substrate is viewed by transmitted light.

[0014] An identification document according to the present disclosure realizes both the barrier effect of the layer of opaque material and the watermark effect of the first and second images depending on whether it is viewed by reflected light or by transmitted light.

[0015] Specifically, in front view of the substrate, when viewed by reflected light, only the first image is visible. The layer of opaque material forms a background against which the first image is displayed. The second image is positioned in viewing direction behind the opaque layer and is not visible. In contrast to that, when viewed by transmitted light, both the first and second images are visible (in front view of the substrate). In that case, the layer of opaque material allows light to pass through in such a degree that the second image becomes visible.

[0016] The same applies vice versa. That means that in back view, when viewed by reflected light, only the second image is visible. The layer of opaque material forms a background against which the second image is displayed. The first image is positioned in viewing direction behind the opaque layer and is not visible. In contrast to that, when viewed by transmitted light, both the first and second images are visible (in back view of the substrate). In that case, the layer of opaque material allows light to pass through in such a degree that the first image becomes visible.

[0017] The present disclosure provides an image (such as a laserable image) in front and back of a layer of opaque material (such as opaque white ink) positioned in a transparent window. The layer of opaque material acts as an interlock (barrier) for the images in the transparent window when observed in reflected light. Further, the back image acts as a watermark to the front image when observed against the light and vice-versa. In reflection, the image is observed without any watermark.

[0018] In the context of the present disclosure, when an image has a watermark effect on another image, then the image is positioned in thickness direction of the substrate behind the another image and is at least partly visible in the background of the another image. The image may (at least partly) overlap with the another image in thickness direction of the substrate or may be positioned (entirely) besides the another image when viewed in thickness direction.

[0019] "Visible" in the context of the present disclosure means that the first or second image is identifiable. Or in other words that the first or second image is distinguishable from (contrast with) the layer of opaque material. Visibility can refer to the naked human eye, but also to machine visibility, e.g., a passport scanner to verify the genuine nature of the document.

[0020] The transparent window extends through the entire substrate from the frontside to the backside of the substrate. To create a transparent window in a substrate, all known technologies may be used.

[0021] Opacity is the property of an object that resists the passage of light. This is calculated by measuring the percentage of the light which is transmitted. Opacity = 100% (1-I1 / I0), wherein I1 = remaining intensity of light after having passed the object, and I0 = initial intensity of light before having passed the object. Opacity may also be expressed in form of transmittance (transparency). The following correlation applies: opacity = 100% - transmittance (transparency).

[0022] In this disclosure, the meaning of the expression "opaque" is that essentially no light of a specific wavelength range is transmitted. Preferably, a transmittance is less than about 40%, more preferably less than about 20%. This corresponds to an opacity of more than 60%, more preferably more than 80%.

[0023] In this disclosure, the meaning of the expression "transparent" is that essentially all light of a specific wavelength range is transmitted. Preferably, a transmittance is more than 60%, more preferably more than 80%. This corresponds to an opacity of less than 40%, more preferably less than 20%.

[0024] If not otherwise specified, opacities and transmittances (transparencies) in this disclosure are measured in thickness direction of the substrate.

[0025] Each of the first and second images at least partly overlap with the layer of opaque material in thickness direction of the substrate. An overlap in thickness direction of the substrate means that, when viewed in thickness direction of the substrate, the first image is positioned in front of (or behind) the second image. The first and second image may be any visual representation. For example, the first and second images may be a portrait, a date of birth, a signature, etc.

[0026] Reflected light refers to any light that encounter a surface (such as a surface of the layer of opaque material or the frontside / backside of the substrate) that reflects the light away. In contrast, transmitted light refers to light that hits an object and travels all the way through (such as a transparent window of the substrate). Light is not limited to visible light but may also refer to IR light and / or UV light.

[0027] The substrate may be formed of multiple layers stacked on each other using standard techniques which are well known in the industry. The substrate respectively the multiple layers may for example be made of Polycarbonate (PC), PVC, Teslin or TPU. In case the substrate is formed of multiple layers stacked on each other, the multiple layers may include at least one opaque layer with a transparent window and at least one transparent layer of which a portion is covered with opaque material. The opaque material that covers a portion of the transparent layer corresponds to the layer of opaque material. The multiple layers may comprise further layers (either opaque layer with transparent window or transparent layers) on which the first image and the second image are applied.

[0028] In an exemplary embodiment, the first image and / or the second image is laser engraved. Laser engraving an image in a substrate of an identification document is a well-known technology to the skilled person. The image may be laser engraved in the substrate directly (such as a polycarbonate layer) or additional material layers may be provided on which the image is laser engraved. Ns, fs or any pulsed laser or continuous laser may be used. When laser engraving the first and / or second image, for example the following parameters may be used: f: 50-150 kHz; v: 2000-4000 mm / s; P: 10-20 W.

[0029] The layer of opaque material may for example be made of ink. 592-00 / PC_200 ink from Printcolor is an example for an ink that may be used. The thickness of such layer of ink may be in the range of 5-20 micrometer, more preferably in the range of 10-15 micrometer. The ink may for example be applied onto a transparent layer of the substrate by inkjet-printing or other technologies known by the skilled person. The ink may be of white color. White color provides a neutral background against which the first image and the second image and potential further identification features which may be provided on the substrate (in the portion of the transparent window) may be displayed.

[0030] The layer of opaque material may be positioned in the substrate such that, in front view and / or in back view, the layer of opaque material fills (completes) the transparent window. In such embodiment, the entire portion in which the transparent window is positioned (in front view and back view) is covered by opaque material. The opaque material serves as a background against which the first and second images are displayed.

[0031] The layer of opaque material may have an opacity in the range of 60-80%, preferably in the range of 70-80%. The opacity of the layer of opaque material may be amended by changing the material of the layer of opaque material or by changing the thickness of the layer of opaque material.

[0032] In an exemplary embodiment, the first and second images are greyscale images. The greyscale values of the first and second images are matched to the opacity of the layer of opaque material such that in front view of the substrate, when viewed by transmitted light, the second image is at least partly visible, and in back view of the substrate, when viewed by transmitted light, the first image is at least partly visible. By matching the greyscale values of the first and second images to the construction of the identification document (especially the opacity of the layer of opaque material), the two images may be merged and have a watermark effect on each other when viewed by transmitted light.

[0033] To avoid to damage the layer of opaque material when applying the first and second images to the substrate (e.g., when laser engraving the first and second images), each of the first and second images may have a minimum distance from the layer of opaque material. For example, the minimum distance between the first image and the layer of opaque material and / or the minimum distance between the second image and the layer of opaque material is greater than 50 µm, preferably greater than 100 µm. The minimum distance between the first image and the layer of opaque material and / or the minimum distance between the second image and the layer of opaque material may be less than 200 µm.

[0034] In an exemplary embodiment, the first and second images may be provided on the layer of opaque material itself without any distance. In that case, the layer of opaque material may for example be formed by white Polycarbonate (PC).

[0035] The first and second images may at least partly overlap each other when viewed in thickness direction of the substrate. In other words, when viewed from the frontside of the substrate at least portions of the second image are positioned behind at least portions of the first image. When viewed from the backside of the substrate, the vice versa applies accordingly. According to this embodiment, the two images have a watermark effect on each other in which one image lies at least partly behind the other image. The first and second images may be configured such that they complement (align with) each other.

[0036] The first and second images may alternatively be arranged in the transparent window such that they are positioned entirely next to each other when viewed in thickness direction of the substrate. No portions of the first and second images overlap with each other. The first and second images may complement each other. The first image may for example form a first part of a combined image and the second image may form a second part of the combined image. Together, the first and second images form the entire combined image. According to this embodiment, the two images have a watermark effect on each other in which one image lies beside the other image and not portions of the first and second images overlap with each other. The first and second images may be configured such that they complement (align with) each other.

[0037] In an exemplary embodiment, the frontside and / or backside of the substrate has a background portion which is adjacent to the transparent window and which has the same color as the layer of opaque material.

[0038] As the color of the layer of opaque material and the color of the background portion are the same, in front view / back view the transparent window (the layer of opaque material) is not distinguishable in reflected light. For example, the color of the layer of opaque material and the color of the background portion may be white. When viewed in reflected light, for the observer it is not possible to identify where the transparent window and where the layer of opaque material is positioned (camouflage effect). The background portion may entirely surround the transparent window. In an exemplary embodiment, the substrate and the layer of opaque material are completely transparent.

[0039] In an exemplary embodiment, the frontside and / or backside of the substrate has a background portion which is adjacent to the transparent window and which has a different opacity than the layer of opaque material. Due to the differences in opacities, in front view and in back view, the layer of opaque material forms a pattern on the frontside respectively the backside of the substrate. The pattern is visible only when viewed by transmitted light but not by reflected light.

[0040] According to this embodiment, the layer of opaque material has a further function, namely to provide a pattern on the frontside / backside of the substrate as an additional security element. The pattern may have any shape. Just to give some examples, the pattern may have the shape of a star, a globe, a rectangle or an animal such as an eagle. The pattern is only visible in transmitted light.

[0041] In a further exemplary embodiment, the frontside and / or backside of the substrate has a background portion which is adjacent to the transparent window and which has a third image. The third image complements (supplements, completes) the first image and / or second image.

[0042] By providing a third image, the security of the identification document is further increased. In this embodiment, the first and / or second image may form a complete image only together with the third image. The third image may for example be an addition (supplement) of the first and / or second image. The third image may for example correspond to the year of a date of birth, wherein the first image corresponds to the day and month of the date of birth. Only together, the third and first image form the entire date of birth. If one of the third or first image is forged, the combined image (alignment of the two images) will be different and the forgery becomes obvious.

[0043] According to an exemplary embodiment, the layer of opaque material is not continuously opaque but has one or more transparent portions, being arranged in the transparent window.

[0044] Through the transparent portions of the layer of opaque material it is possible to see what is behind the substrate (background). In most cases, this visible background will have another color than the color of the layer of opaque material. Accordingly, the transparent portions are visible (identifiable) within the layer of opaque material when viewed in reflected light and when viewed in transmitted light. This effect may be used to further increase the security of the identification document.

[0045] Fig. 1 shows a sectional view of an exemplary embodiment of the identification document. The identification document has the substrate 5. The substrate 5 has a frontside FS and a backside BS opposite to the frontside FS in a thickness direction t. A transparent window 10 extends from the frontside FS of the substrate to the backside BS of the substrate 5. The substrate 5 is formed by multiple layers 6,7 stacked on each other. The stack of layers has four opaque layers 6 in which the transparent window 10 is formed. The stack of layers has two transparent layers 7. For better visibility, only the opaque layers 6 of the substrate 5 are illustrated with hatching. The transparent layers 7 of the substrate 5 are not illustrated with hatching. A layer of opaque material 15 is positioned in the transparent window 10. A first image 20 is positioned in the transparent window 10 between the layer of opaque material 15 and the frontside FS of the substrate 5. The first image 20 overlaps with the layer of opaque material in thickness direction t. A second image 25 is positioned in the transparent window 10 between the layer of opaque material 15 and the backside BS of the substrate 5. The second image 25 overlaps with the layer of opaque material 15 in thickness direction t. The layer of opaque material 15 has a thickness t1. The layer of opaque material 15 is spaced from the first image 20 by the distance d1. Distance d1 is measured between the frontside of the layer of opaque material (the side of the layer of opaque material 15 which is directed towards the frontside of the substrate 5) and the backside of the first image 20 (the side of the first image which is directed towards the backside of the substrate 5). The layer of opaque material 15 is spaced from the second image 25 by the distance d2. Distance d2 is measured between the backside of the layer of opaque material (the side of the layer of opaque material which is directed towards the backside of the substrate 5) and the frontside of the second image (the side of the second image which is directed towards the frontside of the substrate). Even though not shown in Fig. 1, of course, further known security elements such as UV inks, IR inks, printed artwork, may be provided in the transparent window.

[0046] Fig. 2 I-IV show the exemplary embodiment of the identification document of Fig. 1 in front view and back view of the substrate as well as in reflected light and in transmitted light.

[0047] Fig. 2I shows the substrate 5 in front view when viewed by reflected light. The sectional view of Fig. 1 extends along A-A in Fig. 2I. In the substate 5 a transparent window 10 is provided. In the transparent window 10 the first image 20 and the layer of opaque material 15 is visible. The first image 20 is a portrait. The layer of opaque material 15 forms a background against which the first image 20 is displayed. Even though not shown in Fig. 1, of course, further identification features and / or security features and / or artwork may be provided on the frontside FS of the substrate 5.

[0048] Fig. 2II shows the substrate 5 in front view when viewed by transmitted light. Fig. 2II corresponds to Fig. 2I but differs in that in the transparent window 10 in addition to the first image 20 also the second image 25 is visible. The second image 25 is a sequence of numbers representing a date of birth. The second image 25 appears as watermark to the first image 20. The first and second images 20, 25 overlap each other. The layer of opaque material 15 forms a background against which the first image 20 and the second image 25 is displayed (the layer of opaque material is positioned behind the first image 20 and in front of the second image 25).

[0049] Fig. 2III shows the substrate 5 in back view when viewed by reflected light. In the transparent window 10 the second image 25 and the layer of opaque material 15 is visible. The layer of opaque material 15 forms a background against which the second image 25 is displayed. Even though not shown in Fig. 1, of course, further identification features and / or security features and / or artwork may be provided on the backside BS of the substrate 5.

[0050] Fig. 2IV shows the substrate in back view when viewed by transmitted light. Fig. 2IV corresponds to Fig. 2III but differs in that in the transparent window 10 in addition to the second image 25 also the first image 20 is visible. The first image 20 appears as watermark to the second image 25. The first and second images 20, 25 overlap each other. The layer of opaque material 15 forms a background against which the first image 20 and the second image 25 is displayed (the layer of opaque material is positioned behind the second image 25 and in front of the first image 20).

[0051] Fig. 3 I-II show a further exemplary embodiment of the identification document in front view in reflected light and transmitted light.

[0052] Fig. 3I shows the substrate 5 in front view when viewed by reflected light. In the substate 5 a transparent window 10 is provided. In the transparent window 10 the first image 20 is visible. The portion which is adjacent to the transparent window 10 is referred to as background portion 40. The transparent window 10 (the layer of opaque material 15) is not identifiable, distinguishable from the background portion 40 as the color 16 of the layer of opaque material 15 and the color 41 of the background portion 40 are the same. The dashed line of the transparent window indicates that it is not identifiable.

[0053] Fig. 3II shows the substrate 5 in front view when viewed by transmitted light. Fig. 3II corresponds to Fig. 3I but differs in that in the transparent window 10 in addition to the first image 20 also the second image 25 is visible. Still, the transparent window 10 (the layer of opaque material 15) is not identifiable, distinguishable from the background portion 40 as the colors 16, 41 of the layer of opaque material 15 and the background portion as well as the opacities 17, 42 of the layer of opaque material 15 and the background portion are the same.

[0054] Fig. 4 I-II show a further exemplary embodiment of the identification document in front view in reflected light and transmitted light.

[0055] Fig. 4I shows the substrate 5 in front view when viewed by reflected light. In the substate 5 a transparent window 10 is provided. In the transparent window 10 the first image 20 is visible. The portion which is adjacent to the transparent window 10 is referred to as background portion 40. The transparent window 10 (the layer of opaque material 15) is not identifiable, distinguishable from the background portion 40 as the color 16 of the layer of opaque material 15 and the color 41 of the background portion 40 are the same. The dashed line of the transparent window indicates that it is not identifiable.

[0056] Fig. 4II shows the substrate in front view when viewed by transmitted light. Fig. 4II corresponds to Fig. 4I but differs in that in the transparent window in addition to the first image 20 also the second image 25 is visible. The transparent window 10 (the layer of opaque material 15) is now identifiable, distinguishable from the background portion 40 as the opacities 17, 42 of the layer of opaque material 15 and the background portion 40 are the different. As a consequence, the layer of opaque material 15 forms a pattern 30 on the frontside. The pattern shows the country France.

[0057] Fig. 5 I-II show a further exemplary embodiment of the identification document in front view in reflected light and transmitted light.

[0058] Fig. 5I shows the substrate in front view when viewed by reflected light. In the substate 5 a transparent window 10 is provided. In the transparent window 10 the first image 20 and the layer of opaque material 15 is visible. The front side FS has a third image 35. The third image 30 shows two sequences of numbers. Each sequence has an interrupted portion in the middle.

[0059] Fig. 5II shows the substrate 5 in front view when viewed by transmitted light. Fig. 5II corresponds to Fig. 5I but differ in that in the transparent window 10 in addition to the first image 20 also the second image 25 is visible. The second image 25 shows two sequences of numbers. The third image 35 and the second image 25 complement each other. In combination, the third image 35 and the second image 25 represent a date of birth.

[0060] Fig. 6 I-II show a further exemplary embodiment of the identification document in front view in reflected light and transmitted light.

[0061] Fig. 6Ishows the substrate in front view when viewed by reflected light. In the substate 5 a transparent window 10 is provided. In the transparent window 10 the first image 20 and the layer of opaque material 15 is visible. The first image 20 is shaped like a semicircle. Further, a transparent section 45 is provided in the layer of opaque material 15.

[0062] Fig. 6II shows the substrate 5 in front view when viewed by transmitted light. Fig. 6II corresponds to Fig. 6I but differs in that in the transparent window 10 in addition to the first image 20 also the second image 25 is visible. The second image 25 is shaped like a semicircle. The first and second images do not overlap but are arranged next to each other. Together, the first and second images form a full circle.Industrial applicability

[0063] With reference to Fig. 2I-2IV, the use of an exemplary embodiment of the identification document according to the present disclosure is explained. It is assumed that the identification document shown in Fig. I-2IV is a passport. At passport control, a passport inspector may check an identification document as shown in Fig. 2I-2IV. At first, the passport inspector will check the frontside FS of the substrate 5 by reflected light (cf. Fig. 2I). This first check allows to verify whether the first image 20 (portrait) matches the holder of the identity document. Only the first image 20 (and not the second image 25) must be visible. Then, the passport inspector will check the frontside FS of the substrate by transmitted light (by lighting the substrate from the back). This second check allows to verify the second image (date of birth) matches the holder of the identification document (cf. Fig. 2II). The second image 25 must appear as watermark to the first image 20. In a next step, the passport inspector will turn the substrate 5 an observe it from the backside. Again, the passport inspector will first check by reflected light (Fig. 2III). In that case, only the second image (date of birth) seen from behind must be visible. The final step is the check of the backside by transmitted light (Fig. 2IV). The first image 20 must appear as watermark to the second image 20. Due to the watermark effect and the conditional visibility of the first respectively second image, depending from whether it the substrate is observed in reflection or transmission, the transparent window provides a strong security feature. A forge on either the first image or the second image window destroys the whole security element.

[0064] The terms `about', 'approximately', 'circa', 'substantially' or 'generally' as used herein in connection with a measurable value such as a parameter, quantity, shape, time duration or the like, include deviations or variations of ± 10% or less, preferably ± 5% or less, further preferably ± 1% or less and further preferably ± 0.1% of or from the respective value, provided that such deviations are still technically reasonable when the disclosed invention is put into practice. It is expressly pointed out that the value to which the term 'approximately' refers is disclosed as such expressly and in particular. The indication of ranges by initial and final values includes all those values and fractions of these values which are included by the respective range, as well as its initial and final values.

[0065] It is explicitly stated that all features disclosed in the description and / or the claims are intended to be disclosed separately and independently from each other for the purpose of original disclosure as well as for the purpose of restricting the claimed invention independent of the composition of the features in the embodiments and / or the claims. It is explicitly stated that all value ranges or indications of groups of entities disclose every possible intermediate value or intermediate entity for the purpose of original disclosure as well as for the purpose of restricting the claimed invention, in particular as limits of value ranges.List of references

[0066] 5substrate 6transparent layer 7opaque layer with a transparent window 10transparent window 15layer of opaque material 16color of layer of opaque material 17opacity of layer of opaque material 20first image 25second image 30pattern 35third image 40background portion 41color of background portion 42opacity of background portion 45transparent portion FSfrontside of substrate BSbackside of substrate tthickness direction t1thickness of layer of opaque material d1distance from layer of opaque material to first image d2distance from layer of opaque material to second image

Claims

1. An identification document comprising: a substrate (5) having a frontside (FS) and a backside (BS) opposite to the frontside (FS) in a thickness direction (t), a transparent window (10) provided in the substrate (5) such that it extends from the frontside (FS) to the backside (BS) of the substrate (5), a layer of opaque material (15) at least partly positioned in the transparent window (10), a first image (20) positioned in the transparent window (10) between the layer of opaque material (15) and the frontside (FS) of the substrate (5) such that it at least partly overlaps with the layer of opaque material (15) in thickness direction (t), and a second image (25) positioned in the transparent window (10) between the layer of opaque material (15) and the backside (BS) of the substrate (5) such that it at least partly overlaps with the layer of opaque material (15) in thickness direction (t), wherein in front view of the substrate (5), only the first image (20) is visible when viewed by reflected light and both, the first and second images (20, 25) are at least partly visible when viewed by transmitted light, and in back view of the substrate (5), only the second image (25) is visible when viewed by reflected light and both, the second and first images (25, 20) are at least partly visible when viewed by transmitted light.

2. The identification document according to claim 1, wherein the first and / or second image (20, 25) is laser engraved.

3. The identification document according to any one of the preceding claims, wherein the layer of opaque material (15) is made of ink.

4. The identification document according to any one of the preceding claims, wherein the opacity of the layer of opaque material (15) is in the range of 60-80%, preferably in the range of 70-80%.

5. The identification document according to any one of the preceding claims, wherein the first and second images (20, 25) are greyscale images and the greyscale values of the first and second images (20, 25) are matched to the opacity of the layer of opaque material such that in front view of the substrate (5), when viewed by transmitted light, the second image (25) is at least partly visible, and in back view of the substrate (5), when viewed by transmitted light, the first image (20) is at least partly visible.

6. The identification document according to any one of the preceding claims, wherein the minimum distance (d1) between the first image (20) and the layer of opaque material (15) and / or the minimum distance (d2) between the second image (25) and the layer of opaque material (15) is greater than 50 µm, preferably greater than 100 µm.

7. The identification document according to any one of the preceding claims, wherein, in front view and in back view, the layer of opaque material (15) fills the entire transparent window (10).

8. The identification document according to any one of the preceding claims, wherein the substrate (5) is formed of multiple layers (6, 7) stacked on each other, the multiple layers (6, 7) comprising an opaque layer (6) with a transparent window (10) and a transparent layer (7) of which a portion is covered with opaque material.

9. The identification document according to any one of claims 1-8, wherein the first and second images (20, 25) at least partly overlap each other when viewed in thickness direction of the substrate (5).

10. The identification document according to any one of claims 1-8, wherein the first and second images (20, 25) are positioned entirely next to each other when viewed in thickness direction of the substrate.

11. The identification document according to any one of the preceding claims, wherein the frontside (FS) and / or backside of the substrate (5) comprises a background portion (40) which is adjacent to the transparent window (10) and which has the same color (16. 41) as the layer of opaque material (15).

12. The identification document according to any one of the preceding claims, wherein the frontside (FS) and / or backside of the substrate (5) comprises a background portion (40) which is adjacent to the transparent window (10) and which has a different opacity than the layer of opaque material (15), such that in front view and in back view, the layer of opaque material (15) forms a pattern (15) on the frontside (FS) respectively the backside (BS) of the substrate (5), the pattern (15) being visible only when viewed by transmitted light but not by reflected light.

13. The identification document according to any one of the preceding claims, wherein the frontside (FS) and / or backside of the substrate (5) comprises a background portion (40) which is adjacent to the transparent window (10) and which comprises a third image (35), the third image (35) complementing the first and / or second images (20, 25).

14. The identification document according to any one of the preceding claims, wherein the layer of opaque material (15) is not continuously opaque but comprises one or more transparent portions (45).

Images