Identification document with hidden personalized information

Abstract

An identification document (90, 100) has a substrate (1) having a front side (FS) and a back side (BS) opposite to the front side (FS) in a thickness direction (d) of the substrate (1), a transparent window (5) extending through the substrate (1) in the thickness direction (d), a layer of color changing material (20) being positioned at least partly in the transparent window (5) and configured to change its color from a first color (26) to a second color (27) depending on the color of the background (36, 37) against which it is viewed, the second color (27) being different to the first color (26) and a portion with personalized information (10) such as a portrait or a QR-code, the portion with personalized information (10) being positioned at least partly in the transparent window (5) and having a third color (11), the third color being identical to the second color (27). The portion with personalized information (10) is visible when viewing through the transparent window (5) against a first background (36), and not visible when viewing through the transparent window (5) against a second background (37), the second background (37) having a different color to the first background (36).

Description

Technical Field

[0001] The present disclosure generally relates to identification documents. In particular, the present disclosure relates to identification documents with hidden personalized information.Background

[0002] Identification documents are used worldwide. Identification documents 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".

[0003] To verify the identity of the identification document's holder, identification documents are provided with personalized information, also referred to as indicia of identification or identification features of the document holder. Personalized information (indicium of identification) may include the full name, photograph, date of birth, signature of the identification document's holder, or a QR code on which personalized information of the identification document's holder are stored.

[0004] With the increased worldwide use of identification documents, there is a greater risk that personalized information provided on an identification document is stolen or misused. Accordingly, measures to prevent such identity theft are more and more important. Personalized information may be stolen from the original identification document, but may also be stolen from a digital copy of an identification document. Digital copies may be requested when an identification document's holder books a trip, rents a car, etc. The car rental agency may ask the holder of the identification document to send a digital copy of its identification document which may be stored on servers. These servers can be hacked and then the personalized information provided on the identification document may be stolen and misused.

[0005] To prevent identity theft, the identification document's holder may choose to manually hide personalized information by putting a finger or post-it on the portions of the identification document which holds the personalized information, when presenting the identification document to a third person or when scanning the identification document for a digital copy. Another method to prevent identity theft is to add a digital watermark as an anti-copy features which requires extensive computer skills.

[0006] The present disclosure is directed, at least in part, to improving or overcoming one or more aspects of prior systems.Summary of the Disclosure

[0007] According to one aspect of the present disclosure, an identification includes a substrate, a transparent window, a layer of color changing material and a portion with personalized information. The substrate has a front side and a back side opposite to the front side in a thickness direction of the substrate. The transparent window extends through the substrate in the thickness direction. The layer of color changing material is positioned at least partly in the transparent window and is configured to change its color from a first color to a second color depending on the color of the background against which it is viewed. The second color is different to the first color. The portion with personalized information may be a portrait or a QR-code. The portion with personalized information is positioned at least partly in the transparent window and has a third color. The third color is identical to the second color. The layer of color changing material and the portion with personalized information at least partly overlap each other when viewed in the thickness direction of the substrate. The portion with personalized information is visible when viewing through the transparent window against a first background, wherein the layer of color changing material has the first color. The portion with personalized information is not visible when viewing through the transparent window against a second background, wherein the second background has a different color to the first background and the layer of color changing material has the second color..

[0008] In another aspect of the present disclosure, a blank for an identification document includes a substrate, a transparent window, a first layer of color changing material and a second layer configured to be provided with a portion with personalized information. The substrate has a front side and a back side opposite to the front side in a thickness direction of the substrate. The transparent window extends through the substrate in the thickness direction. The first layer of color changing material is positioned at least partly in the transparent window and is configured to change its color from a first color to a second color depending on the color of the background against which it is viewed. The second color is different to the first color. The second layer may be a portrait or a QR-code. The second layer is positioned at least partly in the transparent window and overlaps the first layer of color changing material when viewed in the thickness direction of the substrate.

[0009] In yet another aspect of the present disclosure, a method for providing an identification document with hidden personalized information includes the step of providing a substrate having a front side and a back side opposite to the front side in a thickness direction of the substrate, the step of providing a transparent window extending through the substrate in the thickness direction, the step of providing a layer of color changing material positioned at least partly in the transparent window and the step of providing a second layer positioned at least partly in the transparent window. The layer of color changing material is configured to change its color from a first color to a second color depending on the color of the background against which it is viewed. The second color is different to the first color. The method further includes the step of applying, preferably printing, a portion with personalized information such as a portrait or a QR-code in a third color on the second layer such that the portion with personalized information at least partly overlaps with the layer of color changing material when viewed in the thickness direction of the substrate. The third color and the layer of color changing material are selected such that the portion with personalized information is visible when viewing through the transparent window against a first background, wherein the layer of color changing material has the first color, and such that the portion with personalized information is not visible when viewing through the transparent window against a second background, which is different to the first background, wherein the second background has a different color to the first background and the layer of color changing material has the second color.

[0010] Other features and aspects of the present disclosure will be apparent from the following description and the accompanying drawings.Brief Description of the Drawings

[0011] Fig. 1 is a schematic sectional view on an exemplary embodiment of an identification document according to the present disclosure. Fig. 2 illustrates the identification document of Fig. 1 positioned on a first surface area 30. Fig. 3 illustrates the identification document of Fig. 1 positioned on a second surface area 31 Fig. 4 is a front view on an exemplary embodiment of an identification document according to the present disclosure. Fig. 5 illustrates the same identification document as shown in Fig. 4 but differs in the surface area in front of which the identification document is positioned. Fig. 6 illustrates the same identification document as shown in Fig. 4 but differs in the surface area in front of which the identification document is positioned. Fig. 7 is a sectional view on a further exemplary embodiment of an identification document according to the present disclosure. Fig. 8 illustrates the identification document as shown in Fig. 7 in a state in which the first page 40 is folded onto the second page 50. Fig. 9 illustrates the identification document as shown in Fig. 7 in a state in which the first page 40 is folded onto the third page 60. Detailed Description

[0012] 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.

[0013] The present disclosure is based at least in part on the realization that the security of an identification document such as an identity card or a passport may be increased by providing an identification document in which a layer of color changing material is combined with a portion having personalized information. It has been realized that the color changing effect from a layer of color changing material provides an identification document with different states, and that the different states may be used to selectably and reversibly hide the portion with personalized information, for example, a portrait or a QR code.

[0014] The color changing material is configured to change its color from a first color to a second color depending on the color of the background against which it is viewed. The second color is different to the first color. The color of the portion of personalized information is referred to as a third color.

[0015] The first color, the second color, and the third color are selected such that the identification document may have the following first state and second state:

[0016] In the first state, the third color of the portion with personalized information and the first color of the layer of color changing material are different from each other. As a consequence, the portion with personalized information is visible when the color changing material has the first color. In the first state, the transparent window is positioned in front of a first background which results in the color of the color changing material being the first color.

[0017] In the second state, the third color of the portion with personalized information and the second color of the color changing material are identical. As a consequence, the portion with personalized information is not visible when the color changing material has the second color.. In the second state, the transparent window is positioned in front of a second background which results in the color of the color changing material being the second color. The color of the second background is different to the color of the first background.

[0018] As will be clear to those skilled in the art, the first color and the second color can be interchanged in the above definition of the first state and the second state.

[0019] In this disclosure, a color 1 and a color 2 are considered to be different, if color 1 is visible in front of color 2 or vice versa. The term "visible" may refer to a detection with the human eye and may mean "identifiable with the human eye" or "perceptible with the human eye". The term "visible" may also refer to a detection with a reader machine such as a passport reader machine, a video camera, a scanning machine or the like. In this case, the visibility may rely on the reader machine and not on the human eye. The term "visible" in this case may mean "identifiable with the reader machine" or "perceptible with the reader machine".

[0020] In this disclosure, a color 1 and a color 2 are considered to be identical, if color 1 is not visible in front of color 2 or vice versa. Accordingly, the term "identical" includes such deviations between color 1 and color 2 which are not visible. If the deviations are not visible, the color 1 and color 2 still appear to be identical. The term "not visible" may mean "not identifiable with the human eye" or "hidden for the human eye" or "not perceptible with the human eye". The term "not visible" may also refer to a detection with a reader machine such as a passport reader machine, a video camera, a scanning machine or the like. In this case, the visibility may rely on the reader machine and not on the human eye. The term "not visible" in this case may mean "not identifiable with the reader machine" or "hidden for the reader machine" or "not perceptible with the reader machine".

[0021] The portion with personalized information may for example be a portrait of the document's holder or a 2D-barcode such as QR-code. The QR-code may for example refer to a password to authenticate the document's holder. The QR code can be revealed by the document's holder only when the transparent window is placed in front of a surface area (which is the background for the view through the transparent window) with a specific color. Alternatively, the portion of personalized information may be a document number, a birth date, a fingerprint, an expiry date, or any secure number or image linked to any of the personalized information or image related to the document holder.

[0022] The present disclosure provides a strong anti-copying feature that is easy to understand and widely prevent identity theft. Additionally, this anti-copying feature provides a dynamic visual effect with the reveal of personalized information when the document is moved from a first background (e.g., a white background) to a different second background (e.g., a black background).

[0023] For example, the layer of color changing material may appear red (first color) when viewed on a black background and may appear blue (second color) when viewed on a white background. Further, the color of the personalized information may be blue (third color). In this example, the portion of personalized information will be hidden when the document's holder (citizen) will place a white background behind his document as in this case, both the portion of personalized information and the layer of color changing material appear blue. The portion with personalized information will only be visible when the document's holder places a black background behind the document as in this case, the portion of personalized information will appear blue and the layer of color changing material will appear red.

[0024] Color changing material changes its color depending on the background color against which it is viewed. The use of color changing material in identification documents is already known in several identification documents produced around the world. The color change of the color changing material is reversible and reproducible. Just to give an example, a color changing material according to the present disclosure is available under the trading name O.V.M Fiduciary ink ("Optical Variable Material" Fiduciary ink).

[0025] The substrate may be made of Polycarbonate (PC), PVC, Teslin or TPU and may be formed of multiple layers stacked on each other using standard techniques which are well known in the industry. If the substrate is formed by a stack of multiple layers, one of the multiple layers may be the layer of color changing material and another one of the multiple layers may be provided with the portion with personalized information.

[0026] The portion with personalized information and the layer of color changing material are provided at least partly in a transparent window. The transparent window extends through the entire substrate or in other words extends from the front side of the substrate to the back side of the substrate. The portion with personalized information and the layer of color changing material may for example be positioned in the transparent window such that they are positioned between the front side of the substrate and the back side of the substrate. When the substrate in which the transparent window is provided is formed by multiple layers stacked on each other, each of the portion with personalized information and the layer of color changing material may for example be arranged on one of the layers of the stack.

[0027] According to this disclosure, the feature that the portion with personalized information and the layer of color changing material are positioned at least partly in the transparent window may include the case that the portion with personalized information and / or the layer of color changing material are positioned outside of the transparent window, e.g., on the front side or the back side of the substrate, but are arranged in relation to the transparent window such that they are visible through the transparent window.

[0028] The transparent window allows light to pass through. The light is then reflected by the surface area positioned behind the transparent window and (again) passes through the layer of color changing material and the portion with personalized information. Accordingly, the user observes the layer of color changing material and the portion with personalized information with light reflected on the surface area positioned behind the transparent window. Depending on the color of that surface, the color of the color changing material changes from the first color to the second color. As the transparent window extends through the entire substrate, the portion with personalized information and the layer of color changing material may be viewed from the frontside and / or the backside of the substrate.

[0029] Each color may be characterized by its colorimetric coordinates in a chosen space, for example the CIE 1976 L*a*b color space or the values [R G B] given by a detection system.

[0030] In this disclosure, two colors may be considered to be identical if the difference between the two colors is less than a given tolerance t, and two colors may be considered to be different if the difference between the two colors is greater than a given tolerance t. The expression of the tolerance t depends on the chosen space used to characterize the two colors.

[0031] As for example described in ISO / CIE 11664-4:2019 dated 2019-06 and ISO / CIE 11664-6:2022 dated 2022-08 and CIE 116-1995, Industrial color difference evaluation, 1995, the tolerance t may be expressed by a colorimetric metric such as ΔE*ab, CIE 1994 DeltaE or CIE DE2000 if the two colors are shown in a uniform colorimetric space, such as the CIE 1976 L*a*b* color space. The definition of CIE 1976 has been extended to correct non-uniformities of perception by the human eye by introducing weighting factors. The 1994 and 2000 formulas have succeeded that of 1976. ΔE* 94 is defined in particular in the L*C*h* space using lightness L*, chroma C* and hue h* differences calculated from L*a*b* colorimetric data. Given a color 1 (L* 1 ,a* 1 ,b* 1 ) and another color 2 (L* 2 ,a* 2 ,b* 2 ), the color difference is calculated as follows: and with k C and k H being generally equal to 1. k L , K 1 and K 2 depend on the application and may in the present case be k L = 1, K 1 = 0.045 and K 2 = 0.015.

[0032] A single unit of ΔE (ΔE = 1) expresses the smallest difference between two colors perceived by the human eye.

[0033] If the colors correspond to the RGB values captured by a color imagery system, the tolerance t may be expressed by a maximum difference between the values in each of the channels: { R 1 − R 2 < t G 1 − G 2 < t B 1 − B 2 < t with R 1 G 1 and B 1 corresponding to the values of color 1 and R 2 , G 2 and B 2 corresponding to the values of color 2.

[0034] The tolerance may also be defined according to the colors under consideration by parametric functions, to distinguish, for example, cases where the colors are light or dark: { R 1 − R 2 < t R R 1 G 1 − G 2 < t G G 1 B 1 − B 2 < t B B 1 where t R , t G and t B are continuous functions.

[0035] According to an exemplary embodiment, a color 1 and a color 2 are considered to be different if the tolerance t between the color 1 and the color 2 is greater than a tolerance t of 3, preferably greater than a tolerance t of 5. And a color 1 and a color 2 are considered to be identical if the tolerance t between the color 1 and the color 2 is less than a tolerance t of 3, preferably less than a tolerance t of 1. The calculation of the tolerance t corresponds to the above described calculation of ΔE* 94 for the color difference of color 1 and color 2. According to this embodiment, the tolerance (ΔE* 94 ) between the first color of the color changing material and the third color of the portion with personalized information is greater than 3, preferably greater than 5, when viewing through the transparent window against the first background. Further, the tolerance (ΔE* 94 ) between the second color of the color changing material and the third color of the portion with personalized information is less than 3, preferably less than 1, when viewing through the transparent window against the second background.

[0036] It has been realized that for a tolerance t (ΔE* 94 ) greater than 3, preferably greater than 5, between the first color and the third color, the degree of difference is sufficient to reliably make the portion with personalized information visible. Further, it has been realized that for a tolerance t (ΔE* 94 ) less than 3, preferably less than 1, between the second color and the third color, the degree of similarity is sufficient to reliably hide the portion with personalized information.

[0037] According to an exemplary embodiment, a light source with the same spectrum of light and with the same polarization is used when viewing through the transparent window against the first background respectively the second background.

[0038] The light source may for example be white non-polarized light such as sunlight or may be polarized laser light, fluorescent tubes, or LEDs.

[0039] By using different light sources, the visibility / non-visibility of the portion with personalized information may be adapted to different use cases.

[0040] The portion with personalized information may be inkjet-printed or may be laser-printed. To increase security, the personalized information may be printed in negative.

[0041] The first background (e.g., white background) and the second background (e.g., black background) may correspond to external surface areas (such as the background of a desktop scanner or the surface of a wall, desk, etc.). Alternatively, the first background and second background may also correspond to portions of the identification document itself (e.g., passport with multiple pages).

[0042] According to an exemplary embodiment, the identification document further has a first page, a second page, and a third page. On the first page, the substrate, the transparent window, the portion with personalized information and the layer of color changing material is provided. The second page includes a first surface area. The third page includes a second surface area. The first page, the second page, and the third page are arranged such that the first page is foldable into a first position and into a second position. In the first position, the first page is positioned adjacent to the second page. In the first position the first surface area of the second page faces the substrate and forms the first background when viewing through the transparent window. In the second position, the first page is positioned adjacent to the third page. In the second position the second surface area of the third page faces the substrate and forms the second background when viewing through the transparent window.

[0043] According to this embodiment, the identification document may for example be a passport with multiple pages and a first and second surface area which are provided on a second page respectively on a third page of that passport. On a first page, the layer of color changing material and the portion with personalized information is positioned. By folding the first page in a first position, in which the first page is adjacent to the second page, the first surface area on the second page corresponds to the first background and the personalized information is visible. By folding the first page into a second position, in which the first page is adjacent to the third page, the second surface area on the third page corresponds to the second background and the personalized information is not visible. If in the first position the viewing direction is from the front side to the back side of the substrate, then in the second position the viewing direction is from the back side to the front side of the substrate, i.e., from the opposite side of the substrate compared to the first position.

[0044] The first page is positioned adjacent to the second page (third page), when the first page is folded on top of the second page (third page). In this case, the first page is in contact with the second page (third page). The first page is also considered to be positioned adjacent to the second page (third page), when it is not in contact with the second page (third page), but is positioned so close to the second page (third page) that the first surface area of the second page (the second surface area of the third page) is visible through the transparent window of the first page. In this case, the first surface area (second surface area) forms the first background (second background) when viewing through the transparent window.

[0045] In Fig. 1-9, different fillings (hatchings) are used to illustrate and improve the description of the present disclosure. For the purpose of an intelligible description, in the following description of Fig. 1-9 it is assumed that a black filling of the first surface 30 represent the color black. Further, it is assumed that no filling of the second surface 31 represent the color white. Further, it is assumed that a filling with cross-hatching of the portrait 10 or of the layer of color changing material 20 represent the color blue and that a filling with dot-hatching of the portrait 10 or of the layer of color changing material 20 represent the color red. However, it should be noted that the above-mentioned assignment of color to the fillings (hatchings) are only given as an example and the fillings (hatchings) may represent any other color as well.

[0046] Fig. 1 is a schematic sectional view on an exemplary embodiment of an identification document such as an identity card 90 according to the present disclosure. The identity card 90 includes a substrate 1. The substrate 1 has a front side FS and a backside BS opposite to the front side FS in a thickness direction d of the substrate 1. The identification document further includes a transparent window 5 extending through the substrate 1 in the thickness direction d, a layer of color changing material 20 and a portion of personalized information 10. The personalized information may for example be a portrait of the document's holder or a QR-code storing personalized information of the document's holder. The portion with personalized information 10 and the layer of color changing material 20 are positioned in the transparent window 5 and overlap with each other when viewed in thickness direction d.

[0047] Fig. 2 and Fig. 3 illustrate the identification document 90 of Fig. 1 positioned on a first surface area 30, respectively a second surface area 31. To illustrate the color changing properties of the identification document, some features shown in Fig. 2 and Fig. 3 are illustrated with a special hatching or in white or in black to indicate a specific color, as described in detail in the following.

[0048] In Fig. 2, when viewing through the transparent window 5 from the front side FS to the backside BS of the substrate 1 (viewing direction V is indicated with an arrow), the first surface area 30 is positioned behind the transparent window 5 such that part of it forms a first background 36 of that view through the transparent window 5. Accordingly, the layer of color changing material 20 and the portion with personalized information 10 are viewed against the first background 36. The first surface area 30 respectively the first background 36 has the color black (displayed in black). The third color 11 of the portion with personalized information 10 is blue (displayed with cross-hatching). The first color 26 of the layer of color changing material 20 is red (displayed with dot-hatching). When viewing the layer of color changing material 20 and the portion with personalized information 10 through the transparent window 5, the third color 11 of the portion with personalized information 10 and the first color 26 of the layer of color changing material 20 are different. As a consequence, the portion with personalized information 10 is identifiable.

[0049] In Fig. 3, when viewing through the transparent window 5 from the front side FS to the backside BS of the substrate 1 (viewing direction V is indicated with an arrow), the second surface area 31 is positioned behind the transparent window 5 such that part of it forms a second background 37 of that view through the transparent window 5. Accordingly, the layer of color changing material 20 and the portion with personalized information 10 are viewed against the second background 37. The second surface area 31 respectively the second background 37 has the color white (displayed with no filling). The third color 11 of the portion with personalized information 10 is blue (displayed with cross-hatching). The second color 27 of the layer of color changing material 20 is blue (displayed with cross-hatching). When viewing the layer of color changing material 20 and the portion with personalized information 10 through the transparent window 5, the third color 11 of the portion with personalized information 10 and the second color 27 of the layer of color changing material 20 are identical. As a consequence, the portion with personalized information 10 is not identifiable

[0050] Fig. 4 illustrates a front view on an exemplary embodiment of an identification document such as an identity card 90 according to the present disclosure. The identity card 90 includes a substrate 1 and a transparent window 5 in the upper right corner. The transparent window 5 is positioned in front of a first surface area 30 such that the surface area 30 forms the first background 36 when viewing through the transparent window 5. The first surface area 30 respectively the first background 36 is black (displayed in black). A portrait 10 is positioned in the transparent window 5. In addition, a layer of color changing material 20 is positioned in the transparent window 5. The third color 11 of the portrait 10 is blue (displayed with cross-hatching). The first color 26 of the color changing material 20 is red (displayed with dot-hatching). As the third color 11 of the portion with personalized information 10 is blue and the first color 26 of the layer of color changing material 20 is red, the portion with personalized information 10 (portrait) is identifiable.

[0051] Fig. 5 illustrates the same identification document 90 as shown in Fig. 4 but differs in the surface area, in front of which the identification document 90 is positioned. The transparent window 5 is positioned in front of a second surface area 31 such that the second surface area 31 forms a second background 37 when viewing through the transparent window 5. The second surface area 31 respectively the second background 37 is white (displayed with no filling). In contrast to Fig. 4, in Fig. 5 the layer of color changing material 20 which is positioned in the transparent window 5, is blue (displayed with cross-hatching). As the third color 11 of the portion with personalized information 10 is blue and the second color 27 of the layer of color changing material 20 is blue, the portion with personalized information 10 (portrait) is not identifiable.

[0052] Fig. 6 illustrates the same identification document as shown in Fig. 4 but differs in the surface area, in front of which the identification document is positioned. The transparent window 5 is positioned in front of a surface which partly corresponds to the first background 30 and partly correspond to the second background 31. When viewing through the transparent window 5, the background (first background 36 and second background 37) is partly formed by the first surface area 30 and partly formed by the second surface area 31. In contrast to Fig. 4 and Fig. 5, in Fig. 6 the layer of color changing material 20 which is positioned in the transparent window 5, is partly blue (displayed with cross-hatching) and partly red (displayed with dot-hatching). As the third color 11 of the portion with personalized information 10 is blue and the second color 27 of the layer of color changing material 20 is partly red and partly blue, the portrait 10 is partly visible. Only the part of the portrait 10 which is positioned in front of the layer of color changing material 20 in red is visible.

[0053] Fig. 7 is a sectional view on a further exemplary embodiment of an identification document such as a passport 100 according to the present disclosure. The passport 100 includes a first page 40, a second page 50 and a third page 60. The substrate 1, the transparent window 5, the portion with personalized information 10 and the layer of color changing material 20 are provided on the first page 40. The portion with personalized information 10 and the layer of color changing material 20 are illustrated without any indication of their color. The passport 100 may be folded such that the transparent window 5 is positioned adjacent to the second page 50 or adjacent to the third page 60. The travel path of the transparent window 5 when folding the first page 40 towards the second page 50 or towards the third page 60 is shown in a dashed line. The second page 50 is an end page of the passport 100 and includes a first surface area 30. The first surface area 30 as an example has the color black (displayed in black). The first surface area 30 is positioned on the second page 50 such that in a state in which the first page 40 is adjacent to the second page 50, the first surface area 30 faces the substrate 1. The third page 60 includes a second surface area 31. The second surface area 31 as an example has the color white (displayed with no filling). The second surface area 31 is positioned on the third page 60 such that in a state in which the first page 40 is adjacent to the third page 60, the surface area 31 faces the substrate 1.

[0054] Fig. 8 illustrates the passport 100 as shown in Fig. 7 in a state in which the first page 40 is adjacent to the second page 50. The first page 40 is folded onto the second page 50. When viewed through the transparent window 5 in viewing direction V, the first surface area 30 forms the first background 36 of the view through the transparent window 5. The color of the layer of color changing material 20 has the first color 26 as it is viewed against the first background 36. In Fig. 8, the portion with personalized information 10 and the layer of color changing material 20 are illustrated in a simplified view and their colors are not indicated with any filling.

[0055] Fig. 9 illustrates the passport 100 as shown in Fig. 7 in a state in which the first page 40 is adjacent to the third page 60. The first page 40 is not in contact with the third page 60, but is positioned so close to the third page 60 such that the second surface area 31 of the third page 60 is visible through the transparent window 5 and, when viewed through the transparent window 5 in viewing direction V, forms the second background 37 of the view through the transparent window 5. The color of the layer of color changing material 20 has the second color 27 as it is viewed against the second background 37. In Fig. 9, the portion with personalized information 10 and the layer of color changing material 20 are illustrated in a simplified view and their colors are not indicated with any filling.

[0056] 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

[0057] 1substrate 5transparent window 10portion with personalized information 11third color of portion with personalized information 20layer of color changing material 26first color of layer of color changing material 27second color of layer of color changing material 30first surface area 31second surface area 36first background 37second background 40first page 50second page 60third page 90identity card (identification document) 100passport (identification document) FSfront side BSback side dthickness direction Vviewing direction

Examples

Embodiment Construction

[0012]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.

[0013]The present disclosure is based at least in part on the realization that the security of an identification document such as an identity card or a passport may be increased by providing an identification document in which a layer of color changing material is combined with a portion having personalized information. It has been realized that the color changing effect from a layer of color changing material provi...

Technical Field

[0001] The present disclosure generally relates to identification documents. In particular, the present disclosure relates to identification documents with hidden personalized information.Background

[0002] Identification documents are used worldwide. Identification documents 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".

[0003] To verify the identity of the identification document's holder, identification documents are provided with personalized information, also referred to as indicia of identification or identification features of the document holder. Personalized information (indicium of identification) may include the full name, photograph, date of birth, signature of the identification document's holder, or a QR code on which personalized information of the identification document's holder are stored.

[0004] With the increased worldwide use of identification documents, there is a greater risk that personalized information provided on an identification document is stolen or misused. Accordingly, measures to prevent such identity theft are more and more important. Personalized information may be stolen from the original identification document, but may also be stolen from a digital copy of an identification document. Digital copies may be requested when an identification document's holder books a trip, rents a car, etc. The car rental agency may ask the holder of the identification document to send a digital copy of its identification document which may be stored on servers. These servers can be hacked and then the personalized information provided on the identification document may be stolen and misused.

[0005] To prevent identity theft, the identification document's holder may choose to manually hide personalized information by putting a finger or post-it on the portions of the identification document which holds the personalized information, when presenting the identification document to a third person or when scanning the identification document for a digital copy. Another method to prevent identity theft is to add a digital watermark as an anti-copy features which requires extensive computer skills.

[0006] The present disclosure is directed, at least in part, to improving or overcoming one or more aspects of prior systems.Summary of the Disclosure

[0007] According to one aspect of the present disclosure, an identification includes a substrate, a transparent window, a layer of color changing material and a portion with personalized information. The substrate has a front side and a back side opposite to the front side in a thickness direction of the substrate. The transparent window extends through the substrate in the thickness direction. The layer of color changing material is positioned at least partly in the transparent window and is configured to change its color from a first color to a second color depending on the color of the background against which it is viewed. The second color is different to the first color. The portion with personalized information may be a portrait or a QR-code. The portion with personalized information is positioned at least partly in the transparent window and has a third color. The third color is identical to the second color. The layer of color changing material and the portion with personalized information at least partly overlap each other when viewed in the thickness direction of the substrate. The portion with personalized information is visible when viewing through the transparent window against a first background, wherein the layer of color changing material has the first color. The portion with personalized information is not visible when viewing through the transparent window against a second background, wherein the second background has a different color to the first background and the layer of color changing material has the second color..

[0008] In another aspect of the present disclosure, a blank for an identification document includes a substrate, a transparent window, a first layer of color changing material and a second layer configured to be provided with a portion with personalized information. The substrate has a front side and a back side opposite to the front side in a thickness direction of the substrate. The transparent window extends through the substrate in the thickness direction. The first layer of color changing material is positioned at least partly in the transparent window and is configured to change its color from a first color to a second color depending on the color of the background against which it is viewed. The second color is different to the first color. The second layer may be a portrait or a QR-code. The second layer is positioned at least partly in the transparent window and overlaps the first layer of color changing material when viewed in the thickness direction of the substrate.

[0009] In yet another aspect of the present disclosure, a method for providing an identification document with hidden personalized information includes the step of providing a substrate having a front side and a back side opposite to the front side in a thickness direction of the substrate, the step of providing a transparent window extending through the substrate in the thickness direction, the step of providing a layer of color changing material positioned at least partly in the transparent window and the step of providing a second layer positioned at least partly in the transparent window. The layer of color changing material is configured to change its color from a first color to a second color depending on the color of the background against which it is viewed. The second color is different to the first color. The method further includes the step of applying, preferably printing, a portion with personalized information such as a portrait or a QR-code in a third color on the second layer such that the portion with personalized information at least partly overlaps with the layer of color changing material when viewed in the thickness direction of the substrate. The third color and the layer of color changing material are selected such that the portion with personalized information is visible when viewing through the transparent window against a first background, wherein the layer of color changing material has the first color, and such that the portion with personalized information is not visible when viewing through the transparent window against a second background, which is different to the first background, wherein the second background has a different color to the first background and the layer of color changing material has the second color.

[0010] Other features and aspects of the present disclosure will be apparent from the following description and the accompanying drawings.Brief Description of the Drawings

[0011] Fig. 1 is a schematic sectional view on an exemplary embodiment of an identification document according to the present disclosure. Fig. 2 illustrates the identification document of Fig. 1 positioned on a first surface area 30. Fig. 3 illustrates the identification document of Fig. 1 positioned on a second surface area 31 Fig. 4 is a front view on an exemplary embodiment of an identification document according to the present disclosure. Fig. 5 illustrates the same identification document as shown in Fig. 4 but differs in the surface area in front of which the identification document is positioned. Fig. 6 illustrates the same identification document as shown in Fig. 4 but differs in the surface area in front of which the identification document is positioned. Fig. 7 is a sectional view on a further exemplary embodiment of an identification document according to the present disclosure. Fig. 8 illustrates the identification document as shown in Fig. 7 in a state in which the first page 40 is folded onto the second page 50. Fig. 9 illustrates the identification document as shown in Fig. 7 in a state in which the first page 40 is folded onto the third page 60. Detailed Description

[0012] 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.

[0013] The present disclosure is based at least in part on the realization that the security of an identification document such as an identity card or a passport may be increased by providing an identification document in which a layer of color changing material is combined with a portion having personalized information. It has been realized that the color changing effect from a layer of color changing material provides an identification document with different states, and that the different states may be used to selectably and reversibly hide the portion with personalized information, for example, a portrait or a QR code.

[0014] The color changing material is configured to change its color from a first color to a second color depending on the color of the background against which it is viewed. The second color is different to the first color. The color of the portion of personalized information is referred to as a third color.

[0015] The first color, the second color, and the third color are selected such that the identification document may have the following first state and second state:

[0016] In the first state, the third color of the portion with personalized information and the first color of the layer of color changing material are different from each other. As a consequence, the portion with personalized information is visible when the color changing material has the first color. In the first state, the transparent window is positioned in front of a first background which results in the color of the color changing material being the first color.

[0017] In the second state, the third color of the portion with personalized information and the second color of the color changing material are identical. As a consequence, the portion with personalized information is not visible when the color changing material has the second color.. In the second state, the transparent window is positioned in front of a second background which results in the color of the color changing material being the second color. The color of the second background is different to the color of the first background.

[0018] As will be clear to those skilled in the art, the first color and the second color can be interchanged in the above definition of the first state and the second state.

[0019] In this disclosure, a color 1 and a color 2 are considered to be different, if color 1 is visible in front of color 2 or vice versa. The term "visible" may refer to a detection with the human eye and may mean "identifiable with the human eye" or "perceptible with the human eye". The term "visible" may also refer to a detection with a reader machine such as a passport reader machine, a video camera, a scanning machine or the like. In this case, the visibility may rely on the reader machine and not on the human eye. The term "visible" in this case may mean "identifiable with the reader machine" or "perceptible with the reader machine".

[0020] In this disclosure, a color 1 and a color 2 are considered to be identical, if color 1 is not visible in front of color 2 or vice versa. Accordingly, the term "identical" includes such deviations between color 1 and color 2 which are not visible. If the deviations are not visible, the color 1 and color 2 still appear to be identical. The term "not visible" may mean "not identifiable with the human eye" or "hidden for the human eye" or "not perceptible with the human eye". The term "not visible" may also refer to a detection with a reader machine such as a passport reader machine, a video camera, a scanning machine or the like. In this case, the visibility may rely on the reader machine and not on the human eye. The term "not visible" in this case may mean "not identifiable with the reader machine" or "hidden for the reader machine" or "not perceptible with the reader machine".

[0021] The portion with personalized information may for example be a portrait of the document's holder or a 2D-barcode such as QR-code. The QR-code may for example refer to a password to authenticate the document's holder. The QR code can be revealed by the document's holder only when the transparent window is placed in front of a surface area (which is the background for the view through the transparent window) with a specific color. Alternatively, the portion of personalized information may be a document number, a birth date, a fingerprint, an expiry date, or any secure number or image linked to any of the personalized information or image related to the document holder.

[0022] The present disclosure provides a strong anti-copying feature that is easy to understand and widely prevent identity theft. Additionally, this anti-copying feature provides a dynamic visual effect with the reveal of personalized information when the document is moved from a first background (e.g., a white background) to a different second background (e.g., a black background).

[0023] For example, the layer of color changing material may appear red (first color) when viewed on a black background and may appear blue (second color) when viewed on a white background. Further, the color of the personalized information may be blue (third color). In this example, the portion of personalized information will be hidden when the document's holder (citizen) will place a white background behind his document as in this case, both the portion of personalized information and the layer of color changing material appear blue. The portion with personalized information will only be visible when the document's holder places a black background behind the document as in this case, the portion of personalized information will appear blue and the layer of color changing material will appear red.

[0024] Color changing material changes its color depending on the background color against which it is viewed. The use of color changing material in identification documents is already known in several identification documents produced around the world. The color change of the color changing material is reversible and reproducible. Just to give an example, a color changing material according to the present disclosure is available under the trading name O.V.M Fiduciary ink ("Optical Variable Material" Fiduciary ink).

[0025] The substrate may be made of Polycarbonate (PC), PVC, Teslin or TPU and may be formed of multiple layers stacked on each other using standard techniques which are well known in the industry. If the substrate is formed by a stack of multiple layers, one of the multiple layers may be the layer of color changing material and another one of the multiple layers may be provided with the portion with personalized information.

[0026] The portion with personalized information and the layer of color changing material are provided at least partly in a transparent window. The transparent window extends through the entire substrate or in other words extends from the front side of the substrate to the back side of the substrate. The portion with personalized information and the layer of color changing material may for example be positioned in the transparent window such that they are positioned between the front side of the substrate and the back side of the substrate. When the substrate in which the transparent window is provided is formed by multiple layers stacked on each other, each of the portion with personalized information and the layer of color changing material may for example be arranged on one of the layers of the stack.

[0027] According to this disclosure, the feature that the portion with personalized information and the layer of color changing material are positioned at least partly in the transparent window may include the case that the portion with personalized information and / or the layer of color changing material are positioned outside of the transparent window, e.g., on the front side or the back side of the substrate, but are arranged in relation to the transparent window such that they are visible through the transparent window.

[0028] The transparent window allows light to pass through. The light is then reflected by the surface area positioned behind the transparent window and (again) passes through the layer of color changing material and the portion with personalized information. Accordingly, the user observes the layer of color changing material and the portion with personalized information with light reflected on the surface area positioned behind the transparent window. Depending on the color of that surface, the color of the color changing material changes from the first color to the second color. As the transparent window extends through the entire substrate, the portion with personalized information and the layer of color changing material may be viewed from the frontside and / or the backside of the substrate.

[0029] Each color may be characterized by its colorimetric coordinates in a chosen space, for example the CIE 1976 L*a*b color space or the values [R G B] given by a detection system.

[0030] In this disclosure, two colors may be considered to be identical if the difference between the two colors is less than a given tolerance t, and two colors may be considered to be different if the difference between the two colors is greater than a given tolerance t. The expression of the tolerance t depends on the chosen space used to characterize the two colors.

[0031] As for example described in ISO / CIE 11664-4:2019 dated 2019-06 and ISO / CIE 11664-6:2022 dated 2022-08 and CIE 116-1995, Industrial color difference evaluation, 1995, the tolerance t may be expressed by a colorimetric metric such as ΔE*ab, CIE 1994 DeltaE or CIE DE2000 if the two colors are shown in a uniform colorimetric space, such as the CIE 1976 L*a*b* color space. The definition of CIE 1976 has been extended to correct non-uniformities of perception by the human eye by introducing weighting factors. The 1994 and 2000 formulas have succeeded that of 1976. ΔE* 94 is defined in particular in the L*C*h* space using lightness L*, chroma C* and hue h* differences calculated from L*a*b* colorimetric data. Given a color 1 (L* 1 ,a* 1 ,b* 1 ) and another color 2 (L* 2 ,a* 2 ,b* 2 ), the color difference is calculated as follows: and with k C and k H being generally equal to 1. k L , K 1 and K 2 depend on the application and may in the present case be k L = 1, K 1 = 0.045 and K 2 = 0.015.

[0032] A single unit of ΔE (ΔE = 1) expresses the smallest difference between two colors perceived by the human eye.

[0033] If the colors correspond to the RGB values captured by a color imagery system, the tolerance t may be expressed by a maximum difference between the values in each of the channels: { R 1 − R 2 < t G 1 − G 2 < t B 1 − B 2 < t with R 1 G 1 and B 1 corresponding to the values of color 1 and R 2 , G 2 and B 2 corresponding to the values of color 2.

[0034] The tolerance may also be defined according to the colors under consideration by parametric functions, to distinguish, for example, cases where the colors are light or dark: { R 1 − R 2 < t R R 1 G 1 − G 2 < t G G 1 B 1 − B 2 < t B B 1 where t R , t G and t B are continuous functions.

[0035] According to an exemplary embodiment, a color 1 and a color 2 are considered to be different if the tolerance t between the color 1 and the color 2 is greater than a tolerance t of 3, preferably greater than a tolerance t of 5. And a color 1 and a color 2 are considered to be identical if the tolerance t between the color 1 and the color 2 is less than a tolerance t of 3, preferably less than a tolerance t of 1. The calculation of the tolerance t corresponds to the above described calculation of ΔE* 94 for the color difference of color 1 and color 2. According to this embodiment, the tolerance (ΔE* 94 ) between the first color of the color changing material and the third color of the portion with personalized information is greater than 3, preferably greater than 5, when viewing through the transparent window against the first background. Further, the tolerance (ΔE* 94 ) between the second color of the color changing material and the third color of the portion with personalized information is less than 3, preferably less than 1, when viewing through the transparent window against the second background.

[0036] It has been realized that for a tolerance t (ΔE* 94 ) greater than 3, preferably greater than 5, between the first color and the third color, the degree of difference is sufficient to reliably make the portion with personalized information visible. Further, it has been realized that for a tolerance t (ΔE* 94 ) less than 3, preferably less than 1, between the second color and the third color, the degree of similarity is sufficient to reliably hide the portion with personalized information.

[0037] According to an exemplary embodiment, a light source with the same spectrum of light and with the same polarization is used when viewing through the transparent window against the first background respectively the second background.

[0038] The light source may for example be white non-polarized light such as sunlight or may be polarized laser light, fluorescent tubes, or LEDs.

[0039] By using different light sources, the visibility / non-visibility of the portion with personalized information may be adapted to different use cases.

[0040] The portion with personalized information may be inkjet-printed or may be laser-printed. To increase security, the personalized information may be printed in negative.

[0041] The first background (e.g., white background) and the second background (e.g., black background) may correspond to external surface areas (such as the background of a desktop scanner or the surface of a wall, desk, etc.). Alternatively, the first background and second background may also correspond to portions of the identification document itself (e.g., passport with multiple pages).

[0042] According to an exemplary embodiment, the identification document further has a first page, a second page, and a third page. On the first page, the substrate, the transparent window, the portion with personalized information and the layer of color changing material is provided. The second page includes a first surface area. The third page includes a second surface area. The first page, the second page, and the third page are arranged such that the first page is foldable into a first position and into a second position. In the first position, the first page is positioned adjacent to the second page. In the first position the first surface area of the second page faces the substrate and forms the first background when viewing through the transparent window. In the second position, the first page is positioned adjacent to the third page. In the second position the second surface area of the third page faces the substrate and forms the second background when viewing through the transparent window.

[0043] According to this embodiment, the identification document may for example be a passport with multiple pages and a first and second surface area which are provided on a second page respectively on a third page of that passport. On a first page, the layer of color changing material and the portion with personalized information is positioned. By folding the first page in a first position, in which the first page is adjacent to the second page, the first surface area on the second page corresponds to the first background and the personalized information is visible. By folding the first page into a second position, in which the first page is adjacent to the third page, the second surface area on the third page corresponds to the second background and the personalized information is not visible. If in the first position the viewing direction is from the front side to the back side of the substrate, then in the second position the viewing direction is from the back side to the front side of the substrate, i.e., from the opposite side of the substrate compared to the first position.

[0044] The first page is positioned adjacent to the second page (third page), when the first page is folded on top of the second page (third page). In this case, the first page is in contact with the second page (third page). The first page is also considered to be positioned adjacent to the second page (third page), when it is not in contact with the second page (third page), but is positioned so close to the second page (third page) that the first surface area of the second page (the second surface area of the third page) is visible through the transparent window of the first page. In this case, the first surface area (second surface area) forms the first background (second background) when viewing through the transparent window.

[0045] In Fig. 1-9, different fillings (hatchings) are used to illustrate and improve the description of the present disclosure. For the purpose of an intelligible description, in the following description of Fig. 1-9 it is assumed that a black filling of the first surface 30 represent the color black. Further, it is assumed that no filling of the second surface 31 represent the color white. Further, it is assumed that a filling with cross-hatching of the portrait 10 or of the layer of color changing material 20 represent the color blue and that a filling with dot-hatching of the portrait 10 or of the layer of color changing material 20 represent the color red. However, it should be noted that the above-mentioned assignment of color to the fillings (hatchings) are only given as an example and the fillings (hatchings) may represent any other color as well.

[0046] Fig. 1 is a schematic sectional view on an exemplary embodiment of an identification document such as an identity card 90 according to the present disclosure. The identity card 90 includes a substrate 1. The substrate 1 has a front side FS and a backside BS opposite to the front side FS in a thickness direction d of the substrate 1. The identification document further includes a transparent window 5 extending through the substrate 1 in the thickness direction d, a layer of color changing material 20 and a portion of personalized information 10. The personalized information may for example be a portrait of the document's holder or a QR-code storing personalized information of the document's holder. The portion with personalized information 10 and the layer of color changing material 20 are positioned in the transparent window 5 and overlap with each other when viewed in thickness direction d.

[0047] Fig. 2 and Fig. 3 illustrate the identification document 90 of Fig. 1 positioned on a first surface area 30, respectively a second surface area 31. To illustrate the color changing properties of the identification document, some features shown in Fig. 2 and Fig. 3 are illustrated with a special hatching or in white or in black to indicate a specific color, as described in detail in the following.

[0048] In Fig. 2, when viewing through the transparent window 5 from the front side FS to the backside BS of the substrate 1 (viewing direction V is indicated with an arrow), the first surface area 30 is positioned behind the transparent window 5 such that part of it forms a first background 36 of that view through the transparent window 5. Accordingly, the layer of color changing material 20 and the portion with personalized information 10 are viewed against the first background 36. The first surface area 30 respectively the first background 36 has the color black (displayed in black). The third color 11 of the portion with personalized information 10 is blue (displayed with cross-hatching). The first color 26 of the layer of color changing material 20 is red (displayed with dot-hatching). When viewing the layer of color changing material 20 and the portion with personalized information 10 through the transparent window 5, the third color 11 of the portion with personalized information 10 and the first color 26 of the layer of color changing material 20 are different. As a consequence, the portion with personalized information 10 is identifiable.

[0049] In Fig. 3, when viewing through the transparent window 5 from the front side FS to the backside BS of the substrate 1 (viewing direction V is indicated with an arrow), the second surface area 31 is positioned behind the transparent window 5 such that part of it forms a second background 37 of that view through the transparent window 5. Accordingly, the layer of color changing material 20 and the portion with personalized information 10 are viewed against the second background 37. The second surface area 31 respectively the second background 37 has the color white (displayed with no filling). The third color 11 of the portion with personalized information 10 is blue (displayed with cross-hatching). The second color 27 of the layer of color changing material 20 is blue (displayed with cross-hatching). When viewing the layer of color changing material 20 and the portion with personalized information 10 through the transparent window 5, the third color 11 of the portion with personalized information 10 and the second color 27 of the layer of color changing material 20 are identical. As a consequence, the portion with personalized information 10 is not identifiable

[0050] Fig. 4 illustrates a front view on an exemplary embodiment of an identification document such as an identity card 90 according to the present disclosure. The identity card 90 includes a substrate 1 and a transparent window 5 in the upper right corner. The transparent window 5 is positioned in front of a first surface area 30 such that the surface area 30 forms the first background 36 when viewing through the transparent window 5. The first surface area 30 respectively the first background 36 is black (displayed in black). A portrait 10 is positioned in the transparent window 5. In addition, a layer of color changing material 20 is positioned in the transparent window 5. The third color 11 of the portrait 10 is blue (displayed with cross-hatching). The first color 26 of the color changing material 20 is red (displayed with dot-hatching). As the third color 11 of the portion with personalized information 10 is blue and the first color 26 of the layer of color changing material 20 is red, the portion with personalized information 10 (portrait) is identifiable.

[0051] Fig. 5 illustrates the same identification document 90 as shown in Fig. 4 but differs in the surface area, in front of which the identification document 90 is positioned. The transparent window 5 is positioned in front of a second surface area 31 such that the second surface area 31 forms a second background 37 when viewing through the transparent window 5. The second surface area 31 respectively the second background 37 is white (displayed with no filling). In contrast to Fig. 4, in Fig. 5 the layer of color changing material 20 which is positioned in the transparent window 5, is blue (displayed with cross-hatching). As the third color 11 of the portion with personalized information 10 is blue and the second color 27 of the layer of color changing material 20 is blue, the portion with personalized information 10 (portrait) is not identifiable.

[0052] Fig. 6 illustrates the same identification document as shown in Fig. 4 but differs in the surface area, in front of which the identification document is positioned. The transparent window 5 is positioned in front of a surface which partly corresponds to the first background 30 and partly correspond to the second background 31. When viewing through the transparent window 5, the background (first background 36 and second background 37) is partly formed by the first surface area 30 and partly formed by the second surface area 31. In contrast to Fig. 4 and Fig. 5, in Fig. 6 the layer of color changing material 20 which is positioned in the transparent window 5, is partly blue (displayed with cross-hatching) and partly red (displayed with dot-hatching). As the third color 11 of the portion with personalized information 10 is blue and the second color 27 of the layer of color changing material 20 is partly red and partly blue, the portrait 10 is partly visible. Only the part of the portrait 10 which is positioned in front of the layer of color changing material 20 in red is visible.

[0053] Fig. 7 is a sectional view on a further exemplary embodiment of an identification document such as a passport 100 according to the present disclosure. The passport 100 includes a first page 40, a second page 50 and a third page 60. The substrate 1, the transparent window 5, the portion with personalized information 10 and the layer of color changing material 20 are provided on the first page 40. The portion with personalized information 10 and the layer of color changing material 20 are illustrated without any indication of their color. The passport 100 may be folded such that the transparent window 5 is positioned adjacent to the second page 50 or adjacent to the third page 60. The travel path of the transparent window 5 when folding the first page 40 towards the second page 50 or towards the third page 60 is shown in a dashed line. The second page 50 is an end page of the passport 100 and includes a first surface area 30. The first surface area 30 as an example has the color black (displayed in black). The first surface area 30 is positioned on the second page 50 such that in a state in which the first page 40 is adjacent to the second page 50, the first surface area 30 faces the substrate 1. The third page 60 includes a second surface area 31. The second surface area 31 as an example has the color white (displayed with no filling). The second surface area 31 is positioned on the third page 60 such that in a state in which the first page 40 is adjacent to the third page 60, the surface area 31 faces the substrate 1.

[0054] Fig. 8 illustrates the passport 100 as shown in Fig. 7 in a state in which the first page 40 is adjacent to the second page 50. The first page 40 is folded onto the second page 50. When viewed through the transparent window 5 in viewing direction V, the first surface area 30 forms the first background 36 of the view through the transparent window 5. The color of the layer of color changing material 20 has the first color 26 as it is viewed against the first background 36. In Fig. 8, the portion with personalized information 10 and the layer of color changing material 20 are illustrated in a simplified view and their colors are not indicated with any filling.

[0055] Fig. 9 illustrates the passport 100 as shown in Fig. 7 in a state in which the first page 40 is adjacent to the third page 60. The first page 40 is not in contact with the third page 60, but is positioned so close to the third page 60 such that the second surface area 31 of the third page 60 is visible through the transparent window 5 and, when viewed through the transparent window 5 in viewing direction V, forms the second background 37 of the view through the transparent window 5. The color of the layer of color changing material 20 has the second color 27 as it is viewed against the second background 37. In Fig. 9, the portion with personalized information 10 and the layer of color changing material 20 are illustrated in a simplified view and their colors are not indicated with any filling.

[0056] 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

[0057] 1substrate 5transparent window 10portion with personalized information 11third color of portion with personalized information 20layer of color changing material 26first color of layer of color changing material 27second color of layer of color changing material 30first surface area 31second surface area 36first background 37second background 40first page 50second page 60third page 90identity card (identification document) 100passport (identification document) FSfront side BSback side dthickness direction Vviewing direction

Examples

Embodiment Construction

[0012]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.

[0013]The present disclosure is based at least in part on the realization that the security of an identification document such as an identity card or a passport may be increased by providing an identification document in which a layer of color changing material is combined with a portion having personalized information. It has been realized that the color changing effect from a layer of color changing material provi...

Claims

1. An identification document (90, 100) comprising: - a substrate (1) having a front side (FS) and a back side (BS) opposite to the front side (FS) in a thickness direction (d) of the substrate (1), - a transparent window (5) extending through the substrate (1) in the thickness direction (d), - a layer of color changing material (20) being positioned at least partly in the transparent window (5) and configured to change its color from a first color (26) to a second color (27) depending on the color of the background (36, 37) against which it is viewed, the second color (27) being different to the first color (26), and - a portion with personalized information (10) such as a portrait or a QR-code, the portion with personalized information (10) being positioned at least partly in the transparent window (5) and having a third color (11), the third color (11) being identical to the second color (27), wherein the layer of color changing material (20) and the portion with personalized information (10) at least partly overlap each other when viewed in the thickness direction (d) of the substrate (1), the portion with personalized information (10) is visible when viewing through the transparent window (5) against a first background (36), the layer of color changing material (20) having the first color (26), and the portion with personalized information (10) is not visible when viewing through the transparent window (5) against a second background (37), the second background (37) having a different color to the first background (36) and the layer of color changing material (20) having the second color (27).

2. The identification document (90, 100) according to claim 1, wherein when viewing through the transparent window (5) against the first background (36), a tolerance t between the first color (26) of the color changing material (20) and the third color (11) of the portion with personalized information (10) is greater than 3, preferably greater than 5, and when viewing through the transparent window (5) against the second background (37), the tolerance t between the second color (26) of the color changing material (20) and the third color (11) of the portion with personalized information (10) is less than 3, preferably less than 1, wherein the calculation of the tolerance t corresponds to the calculation of ΔE*94, ΔE*94 being calculated as and with kC and kH being equal to 1, kL = 1, K1 = 0.045 and K2 = 0.015.

3. The identification document (90, 100) according to claim 1 or 2, wherein a light source with the same spectrum of light and the same polarization is used when viewing through the transparent window (5) against the first background (36) respectively the second background (37).

4. The identification document (90, 100) according to anyone of claims 1-3, wherein the portion with personalized information (10) is inkjet-printed.

5. The identification document (90, 100) according to anyone of claims 1-3, wherein the portion with personalized information (10) is laser-printed.

6. The identification document (90, 100) according to any one of the preceding claims, wherein the portion with personalized information (10) is displayed in negative.

7. The identification document (100) according to anyone of claims 1-6, further comprising: - a first page (40) on which the substrate (1), the transparent window (5), the portion with personalized data (10) and the layer of color changing material (20) is provided, - a second page (50) comprising a first surface area (30), and - a third page (60) comprising a second surface area (31), wherein the first page (40), the second page (50) and the third page (60) are arranged such that a) the first page (40) is foldable into a first position adjacent to the second page (50), wherein in the first position the first surface area (30) of the second page (50) faces the substrate (1) and forms the first background (36) when viewing through the transparent window (5), and b) the first page (40) is foldable into a second position adjacent to the third page (60), wherein in the second position the second surface area (31) of the third page (50) faces the substrate (1) and forms the second background (36) when viewing through the transparent window (5).

8. A blank for an identification document (90, 100), comprising: - a substrate (1) having a front side (FS) and a back side (BS) opposite to the front side (FS) in a thickness direction (d) of the substrate (1), - a transparent window (5) extending through the substrate (1) in the thickness direction (d), - a first'layer of color changing material (20) being positioned at least partly in the transparent window (5) and configured to change its color from a first color (26) to a second color (27) depending on the color of the background (36, 37) against which it is viewed, the second color (27) being different to the first color (26), and - a second layer configured to be provided with a portion with personalized information (10) such as a portrait or a QR-code, the second layer being positioned at least partly in the transparent window (5) and overlapping the first layer of color changing material (20) when viewed in the thickness direction (d) of the substrate (1).

9. The blank for an identification document (90, 100) according to claim 8, wherein the second layer comprises a coating, the coating being irradiable by laser such that a colored portion of personalized information (10) such as a portrait or a QR-code is formed in the coating.

10. A method for providing an identification document (90, 100) with hidden personalized information, the method comprising: - providing a substrate (1) having a front side (FS) and a back side (BS) opposite to the front side (FS) in a thickness direction (d) of the substrate (1), a transparent window (5) extending through the substrate (1) in the thickness direction (d), a layer of color changing material (20) at least partly in the transparent window (5), the layer of color changing material (20) being configured to change its color from a first color (26) to a second color (27) depending on the color of the background (36, 37) against which it is viewed, the second color (27) being different to the first color (26), and a second layer at least partly in the transparent window (5), and - applying, preferably printing, a portion with personalized information (10) such as a portrait or a QR-code in a third color on the second layer such that the portion with personalized information (10) at least partly overlaps with the layer of color changing material (20) when viewed in the thickness direction (d) of the substrate (1), wherein the third color and the layer of color changing material are selected such that a) the portion with personalized information (10) is visible when viewing the layer of color changing material (20) and the portion with personalized information (10) through the transparent window (5) against a first background (36), the layer of color changing material (20) having the first color (26), and b) the portion with personalized information (10) is not visible when viewing the layer of color changing material (20) and the portion with personalized information (10) through the transparent window (5) against a second background (37), the second background (37) having a different color to the first background (36) and the layer of color changing material (20) having the second color (27).

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