Document with a security feature

Abstract

Document (100) with a security feature comprising: a first substrate layer (103) having a first substrate layer region (105) impregnated with an infrared-absorbing fluid; a second substrate layer (107) arranged on the first substrate layer, wherein the second substrate layer (107) is transparent to infrared light; a second substrate layer region (109) arranged above the first substrate layer region (105), wherein the second substrate layer region (109) has infrared-reflecting particles; wherein the first substrate layer region (105) and the second substrate layer region (109) form a composite infrared security feature which, when irradiated with infrared light, produces a predetermined infrared image.

Description

[0001] The present invention relates to a document with a security feature, a method for verifying the authenticity of the document and a method for producing the document.

[0002] Documents such as passports and banknotes often use infrared-sensitive security features that can be checked with an infrared testing device. For example, on standard euro banknotes, recognizable designs may appear when irradiated with infrared light due to differing infrared absorption of certain printing inks.

[0003] It is therefore an object of the present invention to provide a document with an infrared security feature which is particularly difficult to forge, as well as to provide appropriate methods for verifying and producing the document.

[0004] This task is solved by the features of the independent claims. Advantageous further developments are the subject of the dependent patent claims, the description, and the drawings.

[0005] According to a first aspect, the problem according to the invention is solved by a document with a security feature comprising: a first substrate layer, which has a first substrate layer region impregnated with an infrared-absorbing fluid; a second substrate layer, which is arranged on the first substrate layer, wherein the second substrate layer is transparent to infrared light; a second substrate layer region, which is arranged above the first substrate layer region, wherein the second substrate layer region has infrared-reflecting particles; wherein the first substrate layer region and the second substrate layer region form a composite infrared security feature, which, when irradiated with infrared light, produces a predetermined infrared image.

[0006] This achieves the technical advantage that the predetermined infrared image can represent a characteristic security feature, which, due to a characteristic combination of IR reflection and IR absorption, is particularly difficult to forge. The characteristic security feature can be defined by the proportion and / or distribution of the infrared-absorbing fluid in the first substrate layer. The characteristic security feature can be defined by the proportion and / or distribution of the infrared-reflecting particles in the second substrate layer. The generated infrared image can be compared, for example, manually and / or by a verification device with a reference image to verify the authenticity of the document.

[0007] The second substrate layer can be applied to the first substrate layer, in particular by means of screen printing.

[0008] The first substrate layer can have a thickness between 50 µm and 100 µm, preferably between 60 µm and 90 µm, and particularly preferably between 70 µm and 80 µm.

[0009] The first substrate layer can have a basis weight between 130 g / m². 2 and 150 g / m² 2 exhibit.

[0010] The document can be one of the following: a personal identity card, a passport, an access control card, an authorization card, a company ID card, a tax stamp, a ticket, a birth certificate, a driver's license, a vehicle registration document, or a means of payment, such as a banknote, a bank card, or a credit card.

[0011] According to one embodiment, the second substrate layer area is formed in the second substrate layer or formed on the second substrate layer, or arranged between the first substrate layer and the second substrate layer.

[0012] If the second substrate layer area is formed within the second substrate layer, then the technical advantage is achieved that the second substrate layer area can only be manipulated by causing noticeable damage to the second substrate layer.

[0013] If the second substrate layer area is formed on the second substrate layer, then the technical advantage is achieved that the second substrate layer area can be formed efficiently.

[0014] According to one embodiment, the second substrate layer area has a predetermined arrangement of the infrared light-reflecting particles.

[0015] This achieves the technical advantage that the predetermined arrangement of the infrared light-reflecting particles can be compared with an arrangement or reflection of a reference image to verify the authenticity of the document.

[0016] According to one embodiment, the first substrate layer region has a particle arrangement of infrared light-absorbing particles, in particular carbon particles, wherein the particle arrangement forms a predetermined particle pattern or wherein the particle arrangement forms an infrared light absorption region.

[0017] This achieves the technical advantage that the particle arrangement of the infrared light-reflecting particles can be compared with a particle arrangement or absorption of a reference image in order to verify the authenticity of the document.

[0018] According to one embodiment, the first substrate layer is completely impregnated with the infrared-absorbing fluid.

[0019] This achieves the technical advantage of efficient production of the first substrate layer. For example, the requirements for the first substrate layer regarding the degree of contamination before impregnation are low, so that even used documents such as banknotes can be used efficiently for document production.

[0020] According to one embodiment, the infrared-absorbing fluid contains carbon particles.

[0021] This offers the technical advantage that the properties of the carbon particles can be used to detect, for example by spectroscopy, the dye impregnation. The characteristic absorption of the carbon particles can be used to verify the authenticity of the document, for example by spectroscopy based on the absorption maximum in the carbon absorption band.

[0022] The infrared-absorbing fluid can have a predetermined volume fraction of carbon, where a shade of the first substrate layer area impregnated with the infrared-absorbing fluid has an L-value according to ISO 5631-2 that is less than 24.

[0023] According to one embodiment, the second substrate layer area has further particles which reflect or absorb incident light with a wavelength outside the infrared light range.

[0024] This achieves the technical advantage that reflection or absorption of the incident light at a wavelength outside the infrared light range can be used to verify the authenticity of the document.

[0025] According to one embodiment, the additional particles are arranged in a pattern that forms a further security feature.

[0026] This achieves the technical advantage that the pattern of the additional particles can be used with a pattern, reflection, or absorption of a reference image to verify the authenticity of the document.

[0027] According to one embodiment, the document includes a third substrate layer area, wherein the third substrate layer area has further particles which reflect or absorb incident light with a wavelength outside the infrared light range, wherein the further particles form a further security feature.

[0028] This achieves the technical advantage that the security feature formed by the additional particles can be used to verify the authenticity of the document.

[0029] The additional security feature can represent alphanumeric characters, in particular a nominal value, a graphic code and / or a pattern of the document.

[0030] This achieves the technical advantage that the additional security feature can be efficiently checked manually and / or automatically.

[0031] According to one embodiment, the third substrate layer area is formed in or on the second substrate layer.

[0032] If the third substrate layer area is formed within the second substrate layer, then the technical advantage is achieved that the third substrate layer area can only be manipulated by causing noticeable damage to the second substrate layer.

[0033] If the third substrate layer area is formed on the second substrate layer, then the technical advantage is achieved that the second substrate layer area can be formed efficiently.

[0034] According to one embodiment, the third substrate layer area and the second substrate layer area are designed to overlap or not overlap.

[0035] If the third substrate layer area and the second substrate layer overlap, then the technical advantage is achieved that the overlap area can be used to verify the authenticity of the document.

[0036] If the third substrate layer area and the second substrate layer are non-overlapping, then the technical advantage is achieved that efficiently assembled patterns can be formed to verify the authenticity of the document.

[0037] According to one embodiment, the second substrate layer region has further particles which reflect or absorb incident light with a first wavelength lying outside the infrared light range, wherein the wavelength with which the further particles of the third substrate layer region reflect or absorb the incident light is a second wavelength, wherein the first wavelength is the same as the second wavelength and in particular the third substrate layer region is free of infrared light-reflecting particles, or wherein the first wavelength is different from the second wavelength and in particular the third substrate layer region has infrared light-reflecting particles.

[0038] If the first wavelength is the same as the second wavelength and, in particular, the third substrate layer area is free of infrared light-reflecting particles, then the technical advantage is achieved that incident light can be reflected or absorbed equally at the second and third substrate layer areas outside the infrared light range, and, in particular, can be reflected or absorbed differently within the infrared light range, which can be used to verify the authenticity of the document.

[0039] If the first wavelength differs from the second wavelength, and in particular if the third substrate layer contains infrared-reflecting particles, then the technical advantage is achieved that incident light can be reflected or absorbed differently outside the infrared range at the second and third substrate layer regions, and, in particular, can be reflected or absorbed identically within the infrared range. This can be used to verify the authenticity of the document. In this case, the volume fraction of infrared-reflecting particles in the third substrate layer region can be equal to the volume fraction of infrared-reflecting particles in the second substrate layer region.

[0040] According to one embodiment, the first substrate layer area is also UV light reflective.

[0041] This achieves the technical advantage that the reflection of incident light at the first substrate layer area can be used to verify the authenticity of the document.

[0042] According to one embodiment, the first substrate layer area is covered with a UV-reflecting layer.

[0043] This achieves the technical advantage that the reflection of incident light at the UV-reflective layer can be used to verify the authenticity of the document.

[0044] According to one embodiment, the infrared-absorbing fluid also has UV-reflecting pigments.

[0045] This achieves the technical advantage that the reflection of incident light at the UV-reflecting pigments can be used to verify the authenticity of the document.

[0046] According to one embodiment, the first substrate layer area extends over the entire first substrate layer.

[0047] This achieves the technical advantage that the entire first substrate layer can be captured to verify the authenticity of the document.

[0048] According to one embodiment, the first substrate layer region has at least one sub-region which is free of the infrared-absorbing fluid.

[0049] This achieves the technical advantage that a difference in the absorption of IR light between the sub-area and the remainder of the first substrate layer area impregnated with infrared-absorbing fluid can be detected to verify the authenticity of the document.

[0050] According to one embodiment, the subregion of the first substrate layer region free of the infrared-absorbing fluid has a first surface area tone value, wherein the first substrate layer region has at least one further subregion which is completely impregnated with the infrared-absorbing fluid, wherein the further subregion has a second surface area tone value, wherein the first surface area tone value gradually transitions into the second surface area tone value in a transition region between the subregion and the further subregion; and / or wherein the first surface area tone value and the second surface area tone value form a contrast at a surface boundary between the subregion and the further subregion.

[0051] If the first surface area tone value gradually transitions into the second surface area tone value in the transition area between the sub-area and the further sub-area, then the technical advantage is achieved that the gradual transition of the surface area tone values ​​in the transition area can be detected in order to verify the authenticity of the document.

[0052] If the first surface area tone value and the second surface area tone value form a contrast at the surface boundary between the sub-area and the further sub-area, then the technical advantage is achieved that the contrast at the surface boundary can be detected in order to verify the authenticity of the document.

[0053] According to one embodiment, the first substrate layer comprises cotton or is formed from cotton.

[0054] This offers the technical advantage of efficiently producing the first substrate layer for documents, making it particularly sustainable and / or durable. For example, the first substrate layer can contain or consist of cotton fibers.

[0055] According to one embodiment, the second substrate layer is a polymer layer, in particular a plastic layer, or a paint layer.

[0056] If the second substrate layer is a polymer layer, this offers the technical advantage that it can be particularly resistant to damage and / or manipulation.

[0057] If the second substrate layer is a color layer, then the technical advantage is achieved that it can be applied particularly efficiently.

[0058] According to one embodiment, the first substrate layer is connected to a support layer, wherein the document has a third substrate layer which is connected to the support layer, the support layer being arranged between the first substrate layer and the third substrate layer.

[0059] This achieves the technical advantage of producing an efficient multi-layered document. The third substrate layer can be identical to the first or different. For example, the third substrate layer can be free of the infrared-absorbing fluid. The document can therefore have the same or different security features on both sides.

[0060] The substrate layer can be a polymer layer, in particular a plastic layer. The substrate layer can have a thickness between 25 µm and 75 µm, preferably between 35 µm and 65 µm, and particularly preferably between 45 µm and 55 µm.

[0061] The third substrate layer can have a thickness between 50 µm and 100 µm, preferably between 60 µm and 90 µm, and particularly preferably between 70 µm and 80 µm.

[0062] The third substrate layer can have a basis weight between 130 g / m². 2 and 150 g / m² 2 exhibit.

[0063] According to one embodiment, the first substrate layer area impregnated with the infrared-absorbing fluid is opaque to visible light and / or IR light.

[0064] This provides the technical advantage of being able to detect the opacity to visible light and / or IR light in order to verify the authenticity of the document.

[0065] According to one embodiment, the first substrate layer, and in particular the third substrate layer, is coated with a protective layer, in particular a transparent varnish, or is free of a protective layer.

[0066] If the first substrate layer, and especially the third substrate layer, is coated with a protective layer, this offers the technical advantage that the first substrate layer can be particularly resistant to damage and / or tampering. The protective layer can be designed to exhibit characteristic wear patterns, which can be used to verify the authenticity of the document.

[0067] If the first substrate layer, and especially the third substrate layer, is free from a protective layer, then the technical advantage is achieved that the document can be produced efficiently, especially in a resource-saving manner.

[0068] According to a second aspect, the problem according to the invention is solved by a method for verifying the authenticity of the document according to the first aspect, comprising: illuminating the document with infrared light; capturing infrared light reflected from the document in an infrared image; comparing the infrared image with a reference infrared image, wherein the authenticity of the document is confirmed if the infrared image matches the reference infrared image.

[0069] This offers the advantage of efficient document verification. Illuminating the document can be achieved, for example, using an infrared LED in a verification device. Capturing the infrared light reflected from the document and creating an infrared image can then be done, for example, using an infrared camera in the verification device.

[0070] According to a third aspect, the problem according to the invention is solved by a method for producing a document with a security feature, comprising: providing a first substrate layer; impregnating a first substrate layer region of the first substrate layer with an infrared-absorbing fluid; providing a second substrate layer with a second substrate layer region, wherein the second substrate layer is transparent to infrared light and the second substrate layer region comprises infrared-reflecting particles; arranging the second substrate layer on the first substrate layer, wherein the second substrate layer region is arranged above the first substrate layer region, and wherein the first substrate layer region and the second substrate layer region form a composite infrared security feature that, when irradiated with infrared light, produces a predetermined infrared image.

[0071] This offers the advantage of efficient document production. The second substrate layer can be applied to the first substrate layer, particularly using screen printing.

[0072] The embodiments of the document described above and below according to the first aspect are also embodiments of the method according to the second aspect and the method according to the third aspect.

[0073] The embodiments of the method described above and below according to the second aspect are also embodiments of the document according to the first aspect and of the method according to the third aspect.

[0074] The embodiments of the method described above and below according to the third aspect are also embodiments of the document according to the first aspect and of the method according to the second aspect.

[0075] Further examples of implementation are explained in more detail with reference to the accompanying drawings. These show: Fig. 1 a schematic representation of a document with a security feature according to an embodiment in a perspective view; Fig. 2 a schematic representation of a document with a security feature according to an embodiment in a perspective view; Fig. 3 a schematic representation of a document with a security feature according to an embodiment in a perspective view; Fig. 4. A schematic flowchart of a procedure for verifying the authenticity of a document according to one embodiment; and Fig. 5 a schematic flowchart of a procedure for producing a document according to one embodiment.

[0076] Fig. Figure 1 shows a schematic representation of a document 100 with a security feature according to an embodiment in a perspective view. The transverse direction 101-1 of the document 100, the longitudinal direction 101-2 of the document 100, and the vertical direction 101-3 of the document 100 are shown in the Fig. 1 schematically represented.

[0077] Document 100 comprises a first substrate layer 103. The first substrate layer 103 may comprise cotton or be formed from cotton. The first substrate layer 103 may be completely impregnated with an infrared-absorbing fluid. The infrared-absorbing fluid may contain carbon particles and / or UV-reflecting pigments.

[0078] The first substrate layer 103 has a first substrate layer region 105, which is impregnated with the infrared-absorbing fluid. The first substrate layer region 105 can extend over, i.e., along the transverse direction 101-1 and longitudinal direction 101-2 of the document 100, the entire first substrate layer 103, or, as shown in the Fig. The first substrate layer 103, as shown in Figure 1, extends over a portion of the first substrate layer 103. The first substrate layer region 105 impregnated with the infrared-absorbing fluid can be opaque to visible light and / or IR light. Furthermore, the first substrate layer region 105 can be UV-reflective and / or covered with a UV-reflective layer. The first substrate layer 103 can be coated with a protective layer, in particular a transparent varnish, or it can be free of a protective layer.

[0079] The first substrate layer region 105 can have a particle arrangement of infrared light-absorbing particles, in particular carbon particles. The particle arrangement of infrared light-absorbing particles can form a predetermined particle pattern or create an infrared light absorption region.

[0080] Document 100 comprises a second substrate layer 107, which is arranged on the first substrate layer 103. The second substrate layer 107 can be a polymer layer, in particular a plastic layer, or a color layer. The second substrate layer 107 is transparent to infrared light.

[0081] Document 100 comprises a second substrate layer region 109, which is arranged above, i.e., in the vertical direction 101-3 of document 100, the first substrate layer region 105. The second substrate layer region 109 can be formed within or on top of the second substrate layer 107. Alternatively, the second substrate layer region 109 can be arranged between the first substrate layer 103 and the second substrate layer 107.

[0082] The second substrate layer region 109 comprises infrared-reflecting particles, in particular in a predetermined arrangement. The second substrate layer region 109 may comprise further particles that reflect or absorb incident light with a first wavelength lying outside the infrared range. The further particles of the second substrate layer region 109 may be arranged in a pattern that forms a further security feature.

[0083] The first substrate layer area 105 and the second substrate layer area 109 form a composite infrared security feature that produces a predetermined infrared image when irradiated with infrared light.

[0084] Fig. Figure 2 shows a schematic representation of a document 100 with a security feature according to one embodiment in a perspective view. The transverse direction 101-1 of the document 100, the longitudinal direction 101-2 of the document 100, and the vertical direction 101-3 of the document 100 are shown in the Fig. 2 schematically represented. To avoid repetition, the following will explain the differences of the [unclear] in the Fig. 2 of the document shown 100 to the one in Fig. Document 100 is described in detail in the document shown.

[0085] As in the Fig. As shown in Figure 2, the first substrate layer region 105 can have at least one sub-region 113. This sub-region 113 can be free of the infrared-absorbing fluid. This sub-region 113 of the first substrate layer region 105 can have a first surface area tone value.

[0086] As further in the Fig. As shown in Figure 2, the first substrate layer region 105 can have at least one further sub-region 115. This at least one further sub-region 115 can be completely impregnated with the infrared-absorbing fluid. This at least one further sub-region 115 can have a second surface area tone value.

[0087] The first surface area tone value can gradually transition into the second surface area tone value in a transition area 117 between at least one sub-area 113 and at least one further sub-area 115. Alternatively or additionally, the first surface area tone value and the second surface area tone value can form a contrast at a surface boundary 119 between at least one sub-area 113 and at least one further sub-area 115.

[0088] Fig. Figure 3 shows a schematic representation of a document 100 with a security feature according to one embodiment in a perspective view. The transverse direction 101-1 of the document 100, the longitudinal direction 101-2 of the document 100, and the vertical direction 101-3 of the document 100 are shown in the Fig. 3 schematically represented. In the following, to avoid repetition, differences of the in the Fig. 3 of the documents shown, 100 to the one in Fig. Document 100 is described in detail in the document shown.

[0089] As in the Fig. As shown in Figure 3, document 100 can include a third substrate layer region 111. The third substrate layer region 111 can be formed within or on top of the second substrate layer 107. As shown in the Fig. As exemplified in Figure 3, the third substrate layer area 111 and the second substrate layer area 109 can be non-overlapping, in particular horizontally adjacent to each other, for example in the transverse direction 101-1 and / or longitudinal direction 101-2 of document 100. Even if this is shown in the Fig. If 3 is not shown, the third substrate layer area 111 and the second substrate layer area 109 can alternatively be designed to overlap, in particular horizontally overlapping, for example in the transverse direction 101-1 and / or longitudinal direction 101-2 of document 100.

[0090] The third substrate layer area 111 may contain further particles which reflect or absorb incident light with a second wavelength outside the infrared light range.

[0091] The first wavelength of the light reflected or absorbed by the other particles of the second substrate layer region 109 can be the same as the second wavelength of the light reflected or absorbed by the other particles of the third substrate layer region 111. The third substrate layer region 111 can be free of infrared-reflecting particles.

[0092] Alternatively, the first wavelength of the light reflected or absorbed by the other particles of the second substrate layer region 109 can be different from the second wavelength of the light reflected or absorbed by the other particles of the third substrate layer region 111. In this case, the third substrate layer region 111 can contain the infrared-reflecting particles.

[0093] The additional particles of the third substrate layer region 111, in particular together with the additional particles of the second substrate layer region 109, can form a further security feature. Furthermore, the infrared light-reflecting particles of the second substrate layer region 109, and in particular of the third substrate layer region 111, can also be part of the further security feature.

[0094] The additional security feature can, for example, represent alphanumeric characters, in particular a face value, a graphic code, and / or a pattern of the document. The additional security feature can be formed from the second substrate layer area 109 and the third substrate layer area 111, for example, as a combination of parts of the face value, parts of the graphic code, or parts of the pattern of the second substrate layer area 109 and the third substrate layer area 111.

[0095] As further in the Fig. As shown in Figure 3, the first substrate layer 103 can be connected to a support layer 121. The document 100 can have a third substrate layer 123, which is connected to the support layer 121. The support layer 121 can be arranged between the first substrate layer 103 and the third substrate layer 123. The third substrate layer 123 can be coated with a protective layer, in particular a transparent varnish, or it can be free of a protective layer.

[0096] The third substrate layer 123 can also be in the Fig. 3. A fourth substrate layer region not shown, which is impregnated with the infrared-absorbing fluid. A fourth substrate layer 125 can be arranged on the third substrate layer 123, wherein the fourth substrate layer 125 is transparent to infrared light. Document 100 may further specify a Fig. The fifth substrate layer area, not shown, comprises three sub-areas located below, i.e., in the vertical direction 101-3 of document 100, the fourth substrate layer area, wherein the fifth substrate layer area contains infrared-reflecting particles. The fourth substrate layer area and the fifth substrate layer area can form a composite third infrared security feature which, when irradiated with infrared light, produces a predetermined further infrared image.

[0097] Alternatively, the third substrate layer 123 can be free of the infrared-absorbing fluid.

[0098] Fig. Figure 4 shows a schematic flowchart of a procedure 400 for verifying the authenticity of a document 100 according to an embodiment.

[0099] Procedure 400 includes illuminating document 100 with infrared light.

[0100] Method 400 further includes capturing 403 infrared light reflected from document 100 in an infrared image.

[0101] The procedure 400 further comprises comparing 405 the infrared image with a reference infrared image, confirming the authenticity of the document 100 if the infrared image matches the reference infrared image.

[0102] Fig. Figure 5 shows a schematic flowchart of a process 500 for producing a document 100 with a security feature according to an embodiment.

[0103] The process 500 includes providing 501 a first substrate layer 103.

[0104] The process 500 further comprises impregnating 503 a first substrate layer area 105 of the first substrate layer 103 with an infrared-absorbing fluid.

[0105] The method 500 further comprises providing 505 a second substrate layer 107 with a second substrate layer area 109, wherein the second substrate layer 107 is transparent to infrared light, and wherein the second substrate layer area 109 has infrared light-reflecting particles.

[0106] Method 500 further comprises arranging 507 the second substrate layer 107 on the first substrate layer 103, wherein the second substrate layer area 109 is arranged above the first substrate layer area 105, wherein the first substrate layer area 105 and the second substrate layer area 109 form a composite infrared security feature which, when irradiated with infrared light, produces a predetermined infrared image.

[0107] It is self-evident that the features of the various exemplary embodiments described herein, in particular the embodiments of Fig. 1, Fig. 2 and Fig.3. can be combined with one another, unless specifically stated otherwise. As shown in the description and drawings, individual elements depicted in conjunction need not be directly connected to one another; intermediate elements may be provided between the connected elements. The term "for example" is meant merely as an example and not as the best or optimal. Certain embodiments have been illustrated and described herein, but it is obvious to the person skilled in the art that a multitude of alternative and / or similar implementations can be realized instead of the embodiments shown and described without departing from the concept of the present invention.

[0108] All features shown or described in connection with individual embodiments of the invention can be provided in any combination in the object according to the invention in order to simultaneously realize their advantageous effects. REFERENCE MARK LIST 100 documents 101-1 Transverse direction of the document 101-2 Longitudinal direction of the document 101-3 Document Setup 103 First substrate layer 105 First substrate layer area 107 Second substrate layer 109 Second substrate layer area 111 Third substrate layer area 113 Sub-area of ​​the first substrate layer area 115 Further sub-area of ​​the first substrate layer area 117 Transition area 119 Surface boundary 121 Carrier layer 123 Third substrate layer 125 Fourth substrate layer 400 methods for verifying the authenticity of a document 401 Illuminating the document with infrared light 403 Detecting infrared light reflected from the document 405 Comparing the infrared image with a reference infrared image 500 methods for creating a document 501 Providing an initial substrate layer 503 Impregnating a first substrate layer area 505 Providing a second substrate layer 507 Arranging the second substrate layer on top of the first substrate layer

Claims

[1] Document (100) with a security feature, comprising: a first substrate layer (103) which has a first substrate layer area (105) which is impregnated with an infrared-absorbing fluid; a second substrate layer (107) which is arranged on the first substrate layer (103), wherein the second substrate layer (107) is transparent to infrared light; a second substrate layer region (109) which is arranged above the first substrate layer region (105), wherein the second substrate layer region (109) has infrared light-reflecting particles; wherein the first substrate layer area (105) and the second substrate layer area (109) form a composite infrared security feature that produces a predetermined infrared image when irradiated with infrared light. [2] Document (100) according to claim 1, wherein the second substrate layer region (109) is formed in the second substrate layer (107) or is formed on the second substrate layer (107) or is arranged between the first substrate layer (103) and the second substrate layer (107). [3] Document (100) according to claim 1 or 2, wherein the second substrate layer region (109) has a predetermined arrangement of the infrared light-reflecting particles. [4] Document (100) according to one of the preceding claims, wherein the first substrate layer region (105) comprises a particle arrangement of infrared light-absorbing particles, in particular carbon particles, wherein the particle arrangement forms a predetermined particle pattern or wherein the particle arrangement forms an infrared light absorption region. [5] Document (100) according to one of the preceding claims, wherein the first substrate layer (103) is completely impregnated with the infrared-absorbing fluid. [6] Document (100) according to one of the preceding claims, wherein the infrared-absorbing fluid comprises carbon particles. [7] Document (100) according to one of the preceding claims, wherein the second substrate layer region (109) has further particles which reflect or absorb incident light with a wavelength outside the infrared light range. [8] Document (100) according to claim 7, wherein the further particles are arranged in a pattern forming a further security feature. [9] Document (100) according to one of the preceding claims, comprising a third substrate layer region (111), wherein the third substrate layer region (111) comprises further particles which reflect or absorb incident light with a wavelength outside the infrared light range, wherein the further particles form a further security feature. [10] Document (100) according to claim 9, wherein the third substrate layer region (111) is formed in or on the second substrate layer (107). [11] Document (100) according to claim 9 or 10, wherein the third substrate layer region (111) and the second substrate layer region (109) are configured to overlap or not overlap. [12] Document (100) according to one of claims 9 to 11, wherein the second substrate layer region (109) comprises further particles which reflect or absorb incident light with a first wavelength lying outside the infrared light range, wherein the wavelength with which the further particles of the third substrate layer region (111) reflect or absorb the incident light is a second wavelength, wherein the first wavelength is equal to the second wavelength and in particular the third substrate layer region (111) is free of infrared light-reflecting particles, or wherein the first wavelength is different from the second wavelength and in particular the third substrate layer region (111) has infrared light-reflecting particles. [13] Document (100) according to one of the preceding claims, wherein the first substrate layer region (105) is furthermore UV light reflective. [14] Document (100) according to one of the preceding claims, wherein the first substrate layer region (105) is covered with a UV-reflecting layer. [15] Document (100) according to one of the preceding claims, wherein the infrared-absorbing fluid further comprises UV-reflecting pigments. [16] Document (100) according to one of the preceding claims, wherein the first substrate layer region (105) extends over the entire first substrate layer (103). [17] Document (100) according to one of the preceding claims, wherein the first substrate layer region (105) has at least one sub-region (113) which is free of the infrared-absorbing fluid. [18] Document (100) according to claim 17, wherein the sub-area (113) of the first substrate layer region (105) free of the infrared-absorbing fluid has a first surface area tone value, wherein the first substrate layer region (105) has at least one further sub-area (115) which is completely impregnated with the infrared-absorbing fluid, wherein the further sub-area (115) has a second surface area tone value, wherein the first surface area tone value gradually transitions into the second surface area tone value in a transition area (117) between the sub-area (113) and the further sub-area (115); and / or wherein the first surface area tone value and the second surface area tone value form a contrast at a surface boundary (119) between the sub-area (113) and the further sub-area (115). [19] Document (100) according to any of the preceding claims, wherein the first substrate layer (103) comprises cotton or is formed from cotton. [20] Document (100) according to one of the preceding claims, wherein the second substrate layer (107) is a polymer layer, in particular a plastic layer, or a color layer. [21] Document (100) according to one of the preceding claims, wherein the first substrate layer (103) is connected to a support layer (121), wherein the document (100) has a third substrate layer (123) which is connected to the support layer (121), wherein the support layer (121) is arranged between the first substrate layer (103) and the third substrate layer (123). [22] Document (100) according to one of the preceding claims, wherein the first substrate layer region (105) impregnated with the infrared-absorbing fluid is opaque to visible light and / or IR light. [23] Document (100) according to one of the preceding claims, wherein the first substrate layer (103), and in particular the third substrate layer (123), is coated with a protective layer, in particular a transparent varnish, or is free of a protective layer. [24] Method (400) for verifying the authenticity of the document (100) according to any one of claims 1 to 23, comprising: Illuminate (401) the document (100) with infrared light; Capturing (403) infrared light reflected from the document (100) in an infrared image; Comparing (405) the infrared image with a reference infrared image, confirming the authenticity of the document (100) if the infrared image matches the reference infrared image. [25] Method (500) for producing a document (100) with a security feature, comprising: Providing (501) a first substrate layer (103); Impregnating (503) a first substrate layer area (105) of the first substrate layer (103) with an infrared-absorbing fluid; Providing (505) a second substrate layer (107) with a second substrate layer region (109), wherein the second substrate layer (107) is transparent to infrared light, and the second substrate layer region (109) has infrared light-reflecting particles; Arranging (507) the second substrate layer (107) on the first substrate layer (103), wherein the second substrate layer area (109) is arranged above the first substrate layer area (105), wherein the first substrate layer area (105) and the second substrate layer area (109) form a composite infrared security feature which, when irradiated with infrared light, produces a predetermined infrared image.

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