DOCUMENT OF IDENTIFICATION WITH OPTICAL LIGHTGUIDE

Abstract

The identification document comprises a personalized area carrying owner-specific information, such as an owner's name data or photograph, The personalized area is overlapped by a lightguide, The lightguide comprises a primary incoupler and a primary outcoupler on opposite sides of the personalized area. Any attempt to tamper with the personalized area may lead to a damage in the lightguide, which can easily be detected by coupling light into the primary incoupler and testing the light coupled out by the primary outcoupler.

Claims

1. A document of identification having a personalized area carrying personalized information identifying an owner of the document and an optical lightguide comprising a primary incoupler and a primary outcoupler, wherein the lightguide forms a protective area between said primary incoupler and said primary outcoupler, wherein said protective area overlaps with at least part of said personalized area.

2. The document of claim 1, wherein said lightguide is arranged below said personalized area.

3. The document of claim 1, wherein said lightguide is arranged above said personalized area.

4. The document of claim 1, wherein said lightguide extends fully across said personalized area.

5. A document of identification having a personalized area carrying personalized information identifying an owner of the document and an optical lightguide comprising a primary incoupler and a primary outcoupler, wherein the lightguide forms a protective area between said primary incoupler and said primary outcoupler, wherein said protective area overlaps with at least part of said personalized area, and wherein said primary incoupler is located laterally at a first side of said personalized area.

6. The document of claim 5, wherein the primary incoupler is arranged laterally outside a first edge of the personalized area, or overlapping with the first edge of the personalized area, wherein said first edge is an edge of the personalized area at said first side.

7. The document of claim 1, wherein said primary outcoupler is located laterally at a second side of said personalized area.

8. The document of claim 7, wherein the primary outcoupler is arranged laterally outside a second edge of the personalized area, or overlapping with the second edge of the personalized area, wherein said second edge is an edge of the personalized area at said second side.

9. The document of, claim 5 wherein said first side is different from said second side, and particular wherein said first side is opposite to said second side.

10. A document of identification having a personalized area carrying personalized information identifying an owner of the document and an optical lightguide comprising a primary incoupler and a primary outcoupler, wherein the lightguide forms a protective area between said primary incoupler and said primary outcoupler, wherein said protective area overlaps with at least part of said personalized area, and wherein at least one of said primary incoupler and said primary outcoupler overlaps with no more than 20% of the personalized area.

11. The document of claim 1, wherein said primary incoupler and/or said primary outcoupler does/do not overlap with the personalized area.

12. A document of identification having a personalized area carrying personalized information identifying an owner of the document and an optical lightguide comprising a primary incoupler and a primary outcoupler, wherein the lightguide forms a protective area between said primary incoupler and said primary outcoupler, wherein said protective area overlaps with at least part of said personalised area, and wherein the lightguide comprises, in at least one of said protective area and said personalized area, no incoupling and/or no outcoupling structures.

13. The document of claim 1, wherein the lightguide comprises a secondary outcoupling structure in said protective area, wherein said secondary outcoupling structure covers no more than 20% of said protective area and for any point in said protective area, a shortest distance to said secondary outcoupler is less than L/3, wherein L is an extension of said protective area in a direction between said primary incoupler and said primary outcoupler.

14. The document of claim 13 wherein said secondary outcoupler comprises at least one line-shaped outcoupler element in said protective area, wherein said line-shaped primary outcoupler has a length of at least 5 mm and an width of no more than 1 mm.

15. The document of claim 1, wherein an overlap between the personalized information in said protective area and said personalized area is at least 1 cm.sup.2.

16. The document of claim 1, wherein, in a direction between said primary incoupler and said primary outcoupler, said protective area has an extension of at least 1 cm.

17. The document of claim 1, wherein in said personalized area, said protective area overlaps with at least one of the following information carriers: writing representing name data of an owner of the document, writing with a date and/or place of birth of the owner of the document, a photograph of the owner of the document, and/or an electronic data carrier carrying identification data of the owner.

18. The document of claim 17, wherein the protective area-overlaps with several of the information carriers.

19. The document of claim 17, wherein the protective area fully overlaps at least one such information carrier.

22. A document of identification having a personalized area carrying personalized information identifying an owner of the document and a first optical lightguide arranged above said personalized area comprising, a primary incoupler and a primary outcoupler, a second optical lightguide arranged below said personalized area comprising a primary incoupler and a primary outcoupler, wherein the lightguides form a protective area between said primary incoupler and said primary outcoupler, wherein said protective area overlaps with at least part of said personalized area.

23. The document of claim 22, wherein the primary incouplers of the first and the second lightguides overlap.

24. The document of claim 22, wherein the primary outcouplers of the first and second lightguides have a non-overlapping area.

25. The document of claim 22, wherein the primary outcouplers of the first and second lightguides have complementary shapes.

26. The document of claim 1, wherein said primary incoupler and/or said primary outcoupler is arranged completely within said personalized area.

27. The document of claim 1, comprising a further security element, in addition to the incoupler and the outcoupler, which is visible in reflection or in transmission.

28. A document of identification having a personalized area carrying personalized information identifying an owner of the document and an optical lightguide comprising a primary incoupler and a primary outcoupler, at least one window located at a location of at least one of said primary incoupler and said primary outcoupler, wherein the lightguide forms a protective area between said primary incoupler and said primary outcoupler, wherein said protective area overlaps with at least part of said personalized area, and.

29. The document of claim 28 wherein said document is adapted to couple, at said window, light from/to a top and a bottom of the document.

30. The document of claim 7 wherein said first side is different from said second side, and particular wherein said first side is opposite to said second side.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0044] The invention will be better understood and objects other than those set forth above will become apparent when consideration is given to the following detailed description thereof. Such description makes reference to the annexed drawings, wherein:

[0045] FIG. 1 is a top view of a first embodiment of a document of identification,

[0046] FIG. 2 is a sectional view (not true to scale) along line II-II of FIG. 1,

[0047] FIG. 3 is a sectional view of a second embodiment,

[0048] FIG. 4 is a sectional view of a third embodiment,

[0049] FIG. 5 is a top view of a fourth embodiment of a document of identification,

[0050] FIG. 6 is a top view of a fifth embodiment of a document of identification with a secondary primary outcoupler,

[0051] FIG. 7 shows a close-up view of the secondary primary outcoupler of FIG. 6,

[0052] FIG. 8 shows a top view of a sixth embodiment of a document of identification,

[0053] FIG. 9 shows a top view of a sixth embodiment of a document of identification with windows, and

[0054] FIG. 10 shows a sectional view (not to scale) along line X-X of FIG. 9.

MODES FOR CARRYING OUT THE INVENTION

First Embodiment and General Aspects

[0055] FIGS. 1 and 2 show a first embodiment of an identification document. The identification document comprises a carrier 10, which can e.g. be of paper and/or plastics. It may be flexible or rigid.

[0056] The identification document shown in FIGS. 1 and 2 may e.g. be a credit-card-sized ID card, a personalized access card, or it may be the personalized page of a passport.

[0057] Carrier 10 may carry visible markings, in particular printed markings, such as writing or graphical elements, as well as any suitable security features. In addition, carrier 10 carries at least one lightguide 12, which can for example be a film of transparent plastics. In general, the lightguide is a thin, substantially 2-dimensional film, patch of films, or stripe of films or a layer of material having a low aspect ratio and whose 2D shape can vary. The lightguide thickness is preferably thinner than 1 mm, in particular thinner than 200 microns, advantageously thinner than 50 microns.

[0058] In general, the ID document may carry other security features, visible or invisible, such features possibly relying on their small dimensions, optical properties, electronics properties, and tactile properties. Such security features may be applied to or integrated in carrier 10, or they may be part of or be formed by other thin foils, paper or plastic substrates, or other parts of the ID document.

[0059] Plastics material is meant to include plastics, reinforced plastic, composite plastics, plastics containing additives, plastic loaded with nanoparticles, microfibers, taggants and the like, cross-linked organic material such as cross-linkable lacquers, hybrid polymer/organic and organic/inorganic matrix materials and the likes, as well as layered films, and do not restrict only to film made of a single polymer.

[0060] The film may for example have a core having a high refractive index and coatings, on one or both sides of the core, of lower refractive index, thereby a preventing the guided light from being coupled out or attenuated by structures adjacent to the lightguide.

[0061] The lower refractive index coatings can be considered as a cladding layer to the core. The core refractive index has advantageously a refractive index higher than 0.05 with respect to the lower refractive index, more advantageously higher by at least 0.1, and even more preferably higher by at least 0.15. In an example, the core may have a refractive index in a given part of the visible spectrum of 1.55 and the cladding 1.4, in another example the core has a refractive index of 1.6 and the cladding of 1.44.

[0062] Lightguide 12 is advantageously light guiding for at least one wavelength in a spectral range between 400 and 1000 nm.

[0063] Lightguide 12 further comprises a primary incoupler 14 and a primary outcoupler 16.

[0064] Primary incoupler 14 may for example be a diffractive grating and/or microlenses. It may be embossed on a surface of lightguide 12, such as on a dedicated surface layer of lightguide 12, and/or embedded within lightguide 12. Alternatively, it may also be formed by a scattering, and/or micro-reflecting and/or fluorescent region of lightguide 12.

[0065] Similarly, primary outcoupler 16 may be embossed on a surface of lightguide 12 and/or embedded within lightguide 12. Alternatively, it may also be formed by an edge of lightguide 12 or by a scattering, diffusing, or fluorescent region of lightguide 12. Such outcoupler may be realized by additive processes, subtractive processes, material modification processes, such as laser irradiation, or by printing a material onto the lightguide that scatters the guided light or fluorescent material that is excited to fluorescence by the guided light.

[0066] Both incoupler 14 and outcoupler 16 may be adapted to respectively incouple/outcouple light from/to one of the two sides or from/to both sides of lightguide 12. The observation of the outcoupled light can be designed to be on the illumination side or to the opposite side with respect to the illumination side.

[0067] The area where the light is guided in lightguide 12 between primary incoupler 14 and primary outcoupler 16 is called the “protective area” 18.

[0068] Identification document 10 further has a personalized area 20, which designates an area of the identification document that carries personalized information of the document's owner.

[0069] Personalized area 20 may e.g. be defined as the convex hull of all or some areas comprising such personalized information. Alternatively, it may e.g. be defined as the area covered by such personalized information.

[0070] In particular, the personalized area may comprise one or more of the following information carriers: [0071] Writing representing name data of the owner of the document. In particular, such writing may include the owner's name 22a and/or signature 22b. [0072] Writing 24 with a date and/or place of birth of the owner of the document, [0073] A photograph 26 of the owner of the document. [0074] An electronic data carrier 28 carrying identification data of the owner. Data carrier 28 is advantageously a memory chip storing individualized data pertinent to the owner, such as name data, biographic data, and/or biometric data. Such a memory chip may be connected to a suitable wireless or wire-bound interface. It can e.g. be an RFID chip. The chip with antenna may be integrated in the data page or in the cover page of passports. [0075] A unique ID number and/or a personalized machine-readable zone (MRZ). A machine-readable zone may e.g. be encoded in plain text and/or in machine-specific (i.e. only machine-readable) encoding (e.g. in barcode or datamatrix, such as QR-code)

[0076] Function

[0077] In general, lightguide 12 may be operated by shining light into primary incoupler 14. At least part of the light is coupled into lightguide 12 and propagates through protective area 18. At least part of the light is then coupled out at primary outcoupler 16.

[0078] If the lightguide is undamaged, all or part of the primary outcoupler 16 will light up.

[0079] If any part of protective area 18 has been damaged, some light will typically fail to arrive at primary outcoupler 16 and give rise to a darker area there, which allows to detect the presence of the damage. A darker area designates an area providing less outcoupled light when light is shined on the incoupler, and may however appear white or clear in color due to a white or clear background. In addition or alternatively thereto, such a damage may act as an outcoupler of its own, which leads to an unexpected bright area in protective area 18, which again can be used to detect the presence of the damage.

[0080] The overlap between protective area 18 and personalized area 20 should be large enough to effectively cover a macroscopic part of personalized area 20. Hence, the overlap between protective area 18 and the personalized information 22a, 22b, 24, 16, 28 in protective area 20 is advantageously at least 1 cm.sup.2, in particular at least 2 cm.sup.2.

[0081] In order to be able to protect a macroscopic region, the distance between primary incoupler 14 and primary outcoupler 16 should be large. Hence, in a direction X between primary incoupler 14 and primary outcoupler 16, protective area 18 advantageously has an extension L of at least 1 cm, in particular of at least 2 cm.

[0082] Advantageously, the extension of primary outcoupler 16 should be large enough to monitor a wide section of the personalized information 22-28. Hence, in a direction Y perpendicular to direction X, primary outcoupler 16 has an extension W of at least 1 cm, in particular of at least 2 cm

[0083] Vertical Placement

[0084] As seen in FIG. 2, lightguide 12 may, in one embodiment, cover the personalized information, such as the writing 22a, 22b, and/or 24, the photograph 26, and/or the data carrier 28, i.e. it is arranged above the personalized information. Thereby, it renders it difficult to gain access to said information from the top side 30 of the identification document, effectively securing the personalized information.

[0085] In another embodiment, which is shown in FIG. 3, lightguide 12 may be arranged below the personalized information, such as the writing 22a, 22b, and/or 24, the photograph 26, and/or the data carrier 28. Thereby, it renders it difficult to gain access to said information from the bottom side 32 of the identification document. In that case, a transparent layer 33 may e.g. be provided above primary incoupler 14 and primary outcoupler 16 and, optionally, between the personalized information 22-28 and lightguide 12. This makes it very difficult to access the personalized information by cutting attacks attempting to split apart the document to access the personalized information, such as the ink marking or photography, as well as attacks from the back of the document or from the back of the datapage, such as grinding attacks.

[0086] In yet another embodiment, which is shown in FIG. 4, the identification document comprises a first lightguide 12a arranged above the personalized information, such as the writing 22a, 22b, and/or 24, the photograph 26, and/or the data carrier 28. It also comprises a second lightguide 12b arranged below the personalized information 22-28. These two lightguides block access to the personalized information from the top side 30 as well as from the bottom side 32.

[0087] As shown, a transparent layer 33 may e.g. be arranged between the first and second primary lightguides 12a, 12b.

[0088] In this embodiment the primary incouplers 14a, 14b of the first and the second lightguides 12a, 12b may overlap, which makes it easier to couple light into both lightguides 12a, 12b with a single light source. For example, the two primary incouplers 14a, 14b have the same size and be centered above each other.

[0089] The primary outcouplers 16a, 16b of the first and the second lightguides 12a, 12b, however, advantageously have at least one non-overlapping area having a large extension along direction Y, in particular of at least 1 cm, in particular of at least 2 cm. This allows to separately monitor the integrity of the protective areas 18 of the two lightguides 12a, 12b when both are illuminated at the same time.

[0090] In the embodiment of FIG. 4, this is achieved by the two primary outcouplers 16a, 16b being parallel to each other and offset in respect to each other.

[0091] Advantageously, the primary outcouplers 16a, 16b of the first and the second lightguides 12a, 12b have complementary shapes located adjacent to each other when viewed from above or from below.

[0092] Horizontal Placement

[0093] In the embodiments of FIGS. 1-4, primary incoupler 14 and primary outcoupler 16 are both arranged laterally outside personalized area 20.

[0094] In particular, primary incoupler 14 is arranged laterally outside a first edge 34 on a first side of personalized area 20, i.e. it does not overlap with any part of the personalized information 22-28 in personalized area 20.

[0095] Similarly, primary outcoupler 16 is arranged laterally outside a second edge 36 on a second side of personalized area 20, i.e. it does not overlap with any part of the personalized information 22-28 in personalized area 20.

[0096] Edges 34 and 36 may be opposite to each other.

[0097] However, primary incoupler 14 and/or primary outcoupler 16 may also overlap with personalized area 20, in particular with the personalized information 22-28 in personalized area 20.

[0098] Said overlap is advantageously small in order to prevent primary incoupler 14 and/or primary outcoupler 16 from affecting the visibility of the personalized information. Hence, advantageously, primary incoupler 14 and/or primary outcoupler 16 overlap with no more than 20%, in particular with no more than 10%, of the personalized area 20, in particular of the area of the personalized information 22-28.

[0099] Advantageously, though, in this case, primary incoupler 14 and/or primary outcoupler 16 is/are not arranged completely within personalized area 20 but overlap with an edge 34, 36 thereof.

[0100] FIG. 5 shows an example where primary outcoupler 16 overlaps edge 36 of personalized area 36 as well as an edge of at least one of the personalized information 22-28.

[0101] Similarly, and in addition or alternatively thereto, incoupler 14 may at least partially overlap personalized area 20, and in particular at least one of the personalized information 22-28, as indicated by a dotted primary incoupler 14′ in FIG. 5.

[0102] Secondary Outcoupler

[0103] In the embodiments shown so far, there are no incoupling or outcoupling structures within protective area 18. This renders protective area 18 basically invisible, which provides excellent visibility of the information in personalized area 20.

[0104] In another embodiment, though, lightguide 12 may comprise a secondary outcoupling structure 40, in addition to primary outcoupler 16, which is also able to couple light out from lightguide 12. This secondary outcoupling structure 40 may be arranged in protective area 18, as illustrated in FIG. 6.

[0105] In that case, however, secondary outcoupling structure 40 is advantageously sparse, as defined above, in order to prevent a large loss of guided light in protective area 18 and/or to not obstruct the personalized information 22-28. In other words, outcoupling structure 16 covers no more than 20%, in particular no more than 10%, of protective area 18.

[0106] In addition, and as illustrated in FIG. 7, any point P within protective area 18 should be close to at least part of outcoupling structure 16. Advantageously, any such point P has a distance d of less than L/3, in particular of less than L/4, in particular less than L/5, in particular less than L/10, from the closest part of secondary outcoupling structure 40.

[0107] This design ensures that no point P on protective area 18 is far away from secondary outcoupling structure 16. Hence, any attempt to counterfeit or forge a macroscopic region of the identity document, for example, such as by removing lightguide 12 locally, splitting it apart from the document, drilling holes through it, locally grinding the document in the protective area and so on is likely to destroy at least part of secondary outcoupling structure 40. This can be detected easily by sending light into lightguide 12 by means of primary incoupler 14 and by optically verifying secondary outcoupling structure 40.

[0108] Primary and/or secondary outcoupling structure 16, 40 may comprise at least one line-shaped element 42. In this context, ‘line-shaped’ means that the line-shaped element 42 extends along straight or curved line as e.g. shown in FIG. 7. Using line-shaped elements has the advantage that they are easily recognized by the eye without requiring a large amount of light.

[0109] For example, primary and/or secondary outcoupling structure 16, 40 may form a guilloche pattern.

[0110] Line-shaped element 42 has a width w (perpendicular to its longitudinal direction) that is much smaller than its length v (along its longitudinal direction). Advantageously, length v is at least 5 mm, in particular at least 10 mm, and/or width w is no more than 1 mm, in particular no more than 0.5 mm, in particular no more than 0.2 mm.

[0111] On the other hand, though, width w is advantageously at least 0.05 mm, advantageously at least 0.1 mm, in order to make the outcoupler well visible to the unaided eye.

[0112] Advantageously, there is a plurality of such line-shaped outcouplers, in particular at least 5, in particular at least 10, in particular at least 100, which allows to distribute them over the protective area for better protection and visual detection.

[0113] The shape of the primary and/or secondary outcoupling structure 16, 40 may vary. The may e.g. also form dots, symbols, characters, etc.

[0114] FIG. 7 also shows, in enlarged fashion, a diffractive grating 44 that can be used to couple light out from lightguide 12.

[0115] Advantageously, secondary outcoupling structure 40 overlaps with at least part of the personalized information 22-28.

[0116] Windows

[0117] FIGS. 9 and 10 show an embodiment where primary incoupler 14 and/or primary outcoupler 16 is/are arranged at windows 52, 54 of the document.

[0118] These windows 52, 54 are designed to be transparent for at least one wavelength that is coupled in/out by primary incoupler 14 and primary outcoupler 16, respectively. In this context, “transparent” advantageously designates that at least 25%, in particular at least 50%, in particular at least 75%, of the light at said wavelength are transmitted through carrier 10 at the location of the window, advantageously without being scattered.

[0119] This has the advantage that light may be coupled in from the top or the bottom of the document, at primary incoupler 14 and/or at primary outcoupler 16.

[0120] In the embodiment of FIG. 9, two such windows 52, 54 are provided, with first window 52 being located at primary incoupler 14 and second window 54 being located at primary outcoupler 16.

[0121] However, there may also be only one such window, e.g. at the location of primary incoupler 14, which would allow to place the document on a light source and illuminate it from below, with light going through first window 52 and being incoupled at primary incoupler 14 and then being seen, from above, at primary outcoupler 16 (or at any secondary outcoupling structure 40 as mentioned above).

[0122] Protective area 18 again may cover at least part of personalized area 20, such as e.g. photograph 36 as shown.

[0123] Notes

[0124] The identification document may comprise further document-specific information outside personalized area 20. In particular, a unique number of the identification document, such as a passport number, may be arranged outside personalized area 20. Even some personalized information may be arranged outside personalized area 20, in which case the lightguide only protects the personalized information it covers at least partially.

[0125] However, advantageously, personalized area 20 at least includes any photograph 26 of the owner and at least one instance of the name data 22a, 22b of the owner, and preferably also any data carrier 28 with owner-specific information.

[0126] In order to distribute the light from a single light source over a large protective area 18, primary incoupler 14 advantageously spreads the light it couples into lightguide 12. Advantageously, it is structured to generate a fan of light in lightguide 10 that has an angular width of at least 20°, advantageously at least 30°. In this context, the width of the fan is defined by the angular range over which the guided light varies within 50% of the maximum intensity.

[0127] Such light fanning can e.g. be achieved by structuring primary incoupler 14 as a curved diffraction grating 46 as illustrated (not to scale) in FIG. 1. It can also be achieved by selecting a coupler having a broad acceptance angle and a non-collimated light source such as a LE), for example the LED flash of a smartphone back-camera.

[0128] In addition or alternatively thereto, primary incoupler 14 advantageously spreads the light it couples into lightguide 12 to illuminate all of the extension W of primary outcoupler 16 (which is e.g. the extension along direction Y in FIG. 1) with a variation of intensity of 50% or less over the whole extension W.

[0129] In the embodiment of FIG. 1 protective area 18 covers all of the writing for name data 22a, 22b, the writing 24 for date of birth, and the data carrier 28. However, it only covers part of photograph 26.

[0130] In general, protective area 18 advantageously overlaps with all or at least 50%, in particular at least 75% of every personalized information in personalized area 20. For example, it may cover photograph 26 fully and/or any other personalized information only partially.

[0131] Primary incoupler 14 and/or primary outcoupler 16 may be adapted to respectively in/out couple light from/to below document, provided the carrier 10 is at least partially transparent in the area where the primary outcoupler and/or primary outcoupler is located. The observation of the outcoupled light can be designed to be on the illumination side or on the opposite side with respect to the illumination side with respect to the document of identification.

[0132] The outcoupler can be made of a fluorescent region, preferably a fluorescent region that is non-homogeneous in color or design. Advantageously the fluorescent outcoupler material is designed to have low absorption in the visible range if located in the personalized area, so that it does not obstruct the reading of the personalized area when no light is shined on the primary incoupler 14. i.e. into the lightguide.

[0133] The primary outcoupler structure 16 may represent at least part of the portrait of the owner of the identification document. In other words, outcoupler structure 16 is personalized to the user, which makes the security feature even harder to fake and easier to verify. This can be realized by additive processes, subtractive processes, material modification processes, such as laser irradiation, or by printing a material onto the lightguide that scatters the guided light or fluorescent material that is excited to fluorescence by the guided light. As an example, a fluorescent portrait of the owner of the identification document may be printed such as it become visible when illumination light is shined on the primary incoupler 14.

[0134] The lightguide may contain several incouplers arranged to couple light into the lightguide and towards the protective area with different main propagation direction or with different spectral composition, i.e. color.

[0135] The primary incoupler 14 may be elongated macroscopically and substantially parallel to one edge of the protective area to provide multiple illumination axes into the lightguide or an easier incoupler to light-source alignment.

[0136] In the embodiments above, neither primary incoupler 14 nor primary outcoupler 16 are completely arranged within the personalized area 20.

[0137] FIG. 8, in contrast thereto, shows an embodiment where with primary incoupler 14 and primary outcoupler 16 are arranged completely within personalized area 20.

[0138] Alternatively, only one of them (i.e. only the incoupler or the outcoupler) could be located completely within personalized area 20 while the other one may be located overlapping with an edge of personalized area 20 or completely outside personalized area.

[0139] Protective area 18 may comprise at least one further visual security element, in addition to the outcoupler structures. Such a security element 50 is shown, by way of example, as a dotted cross in FIG. 1. This further security document is visible in reflection, i.e. by shining light onto the lightguide without coupling it into the lightguide. It renders it difficult to place e.g. a false photograph or another counterfeiting element on top of the lightguide without being detected. Alternatively such a further security element may be controlled in transmission. Such a further visual security element may e.g. be at least one of an optically variable device, such as a diffractive structure, and non-variable markings, such as printed markings.

[0140] Lightguide 10 may be a foil manufactured apart from carrier 10 and then laminated thereto, or it may also be formed in-situ on carrier 10.

[0141] Any incoupler and/or outcoupler mentioned herein may e.g. be a diffractive incoupler/outcoupler, a fluorescent incoupler/outcoupler, an Infrared Upconverting incoupler/outcoupler, an incoupler/outcoupler based on microscopic surface structures (i.e. surface structures without diffractive effects, such as microlenses or micro mirrors or surface structures having a lateral repetition period (i.e. a repetition period within the plane of the lightguide) of e.g. at least 10 μm), diffusing or scattering structures or materials.

[0142] The primary incoupler may also be placed e.g. between two ends of the lightguide, e.g. with two protective areas on different, in particular opposite, sides of it.

[0143] As illustrated by way of example in FIGS. 9 and 10, lightguide 12 may (for any embodiments) be strip-shaped, with a length much larger, in particular at least five times larger, than its width, and advantageously with a constant width along its whole length. It may extend across the whole document. i.e. from one of its edges to the opposite edge.

[0144] While there are shown and described presently preferred embodiments of the invention, it is to be distinctly understood that the invention is not limited thereto but may be otherwise variously embodied and practiced within the scope of the following claims.