Patent Description:
Documents of identification of this type have been known e.g. from <CIT> or <CIT>.

<CIT> describes a carrier representing a monetary value. It has a display device where e.g. the image of an owner of the carrier can be shown. The display device can be backlit from a light guide, which has a surface grating for illuminating the display device.

It has been known to cover the personalized area of such documents by means of a security foil e.g. carrying an embossing or a hologram for generating optical effects and for protecting the personalized information from tampering.

The problem to be solved by the present invention is to improve the protection of at least part of the personalized area.

This problem is solved by the document of identification of claim <NUM>.

Accordingly, the document of identification comprises.

can be coupled out (directly or via a fluorescent process) at the primary outcoupler. The lightguide forms a protective area between the primary incoupler and the primary outcoupler, and this protective area overlaps with at least part of the personalized area.

If a counterfeiter has tried to access the personalized area through the lightguide, the protective area is likely damaged, and this can be detected by coupling light into the primary incoupler and checking for the presence of the light at the primary outcoupler.

The lightguide, and in particular its protective area, may therefore form an anti-tampering seal for at least part of the personalized area.

The term "overlaps with" is to be understood that at least part of the protective area is arranged above or below the personalized area and overlaps with personalized information on the personalized area.

The terms "above" and "top" designate the surface of the document on which the personalized information is visible. If this information is visible from both surfaces of the document, the top surface designates one of these surfaces, advantageously the one where more of the personalized information is visible.

The terms "below" and "bottom" designate the surface of the document opposite to the top surface, i.e. the bottom surface is below the top surface and the top surface is above the bottom surface.

The top and bottom surfaces should advantageously be understood for passports as the surfaces of the data page or of the data pages containing personal information.

Advantageously, the lightguide extends fully across the personalized area. Advantageously, it can extend at least from a first lateral side to a second lateral side of the document. In this context, "lateral" designates any direction perpendicular to the top-bottom-direction.

The primary incoupler is located laterally at a first side of the personalized area. This means that at least part of the primary incoupler is arranged outside (i.e. non-overlapping with) the personalized area. Advantageously, it may be arranged:.

In both cases, the "first edge" is an edge of the personalized area at the first side.

Similarly, the primary outcoupler may be located laterally at a second side of the personalized area. This means that at least part of the primary outcoupler is arranged outside (i.e. non-overlapping with) the personalized area. Advantageously, it may be arranged:.

In both cases, the "second edge" is an edge of the personalized area at the second side.

Advantageously, and when combining these embodiments, the first side is different from the second side such that the lightguide between the primary incoupler and the primary outcoupler extends across the personalized area between these sides.

In particular, the first side is arranged opposite to the second side, which allows the lightguide to protect a whole diametrical section of the personalized area.

In one type of embodiment, the primary incoupler and/or outcoupler may be located in (i.e. overlapping with) the personalized area. It may even fully be located within the personalized area.

If the primary outcoupler and/or outcoupler overlaps at least partially with the personalized area and/or is located fully within the personalized area, it becomes harder to simply cover the personalized area with a fake personalized information carrier, such as a fake photograph.

The overlap of the primary incoupler and/or primary outcoupler with the personalized area is advantageously small in order not to obstruct the view onto the personalized area. Hence, the primary incoupler and/or the primary outcoupler overlap with no more than <NUM>%, in particular with no more than <NUM>%, of the personalized area. Advantageously, the primary incoupler and/or the primary outcoupler do not overlap with the personalized area at all.

In one embodiment, the lightguide comprises no incoupling and/or no outcoupling structures in the personalized and/or protective area, i.e. there are no structures within the personalized and/or protective area for coupling light into the lightguide and/or for coupling light out of the lightguide. This provides an unobstructed view onto the personalized area at the location of the protective area and may render the lightguide at this location substantially invisible. However such a configuration still provides a protective area overlapping with the personalized area as attempts to access the personalized area through the lightguide (i.e. in the overlapping area) would impact the light-guiding properties of the lightguide.

In another embodiment, the lightguide may comprise, in the protective area, a secondary outcoupling structure (in addition to the primary outcoupler). The secondary outcoupling structure fulfils the following conditions:.

These two conditions ensure that the secondary outcoupling structure uses a comparatively small part of the protective area but is, in some sense, distributed over the area, a combination which is termed a 'sparse' outcoupler herein. Such a sparse outcoupler allows to protect a comparatively large area with a small outcoupler coverage. In contrast to this, the primary outcoupler may be concentrated and dense, which makes it well visible but also poorly suited for covering a larger area.

In one embodiment, in the personalized area, the protective area overlaps with at least one of the following information carriers:.

Advantageously, the protective area overlaps with several of these information carriers.

Advantageously, the protective area fully overlaps at least one such information carrier, i.e. on at least one side, the information carrier is fully backed by the protective area such that the information carrier is completely inaccessible.

The lightguide may be arranged below or above the personalized area, with "below" and "above" as defined above. This allows to make access to the personalized area harder from the given side.

The document may also comprise a first lightguide arranged above the personalized area and a second lightguide arranged below the personalized area, in which case the personalized area may be protected from both sides.

The document may e.g. be a passport or a part thereof, or it may be an identification card, access card, etc..

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.

<FIG> show a first embodiment of an identification document. The identification document comprises a carrier <NUM>, which can e.g. be of paper and/or plastics. It may be flexible or rigid.

The identification document shown in <FIG> may e.g. be a credit-card-sized ID card, a personalized access card, or it may be the personalized page of a passport.

Carrier <NUM> may carry visible markings, in particular printed markings, such as writing or graphical elements, as well as any suitable security features. In addition, carrier <NUM> carries at least one lightguide <NUM>, which can for example be a film of transparent plastics. In general, the lightguide is a thin, substantially <NUM>-dimensionnal 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 <NUM>, in particular thinner than <NUM> microns, advantageously thinner than <NUM> microns.

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 <NUM>, or they may be part of or be formed by other thin foils, paper or plastic substrates, or other parts of the ID document.

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.

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 preventing the guided light from being coupled out or attenuated by structures adjacent to the lightguide.

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 <NUM> with respect to the lower refractive index, more advantageously higher by at least <NUM>, and even more preferably higher by at least <NUM>. In an example, the core may have a refractive index in a given part of the visible spectrum of <NUM> and the cladding <NUM>, in another example the core has a refractive index of <NUM> and the cladding of <NUM>.

Lightguide <NUM> is advantageously light guiding for at least one wavelength in a spectral range between <NUM> and <NUM>.

Lightguide <NUM> further comprises a primary incoupler <NUM> and a primary outcoupler <NUM>.

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

Similarly, primary outcoupler <NUM> may be embossed on a surface of lightguide <NUM> and/or embedded within lightguide <NUM>. Alternatively, it may also be formed by an edge of lightguide <NUM> or by a scattering, diffusing, or fluorescent region of lightguide <NUM>. 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.

Both incoupler <NUM> and outcoupler <NUM> may be adapted to respectively incouple/outcouple light from/to one of the two sides or from/to both sides of lightguide <NUM>. 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.

The area where the light is guided in lightguide <NUM> between primary incoupler <NUM> and primary outcoupler <NUM> is called the "protective area" <NUM>.

Identification document <NUM> further has a personalized area <NUM>, which designates an area of the identification document that carries personalized information of the document's owner.

Personalized area <NUM> 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.

In particular, the personalized area may comprise one or more of the following information carriers:.

In general, lightguide <NUM> may be operated by shining light into primary incoupler <NUM>. At least part of the light is coupled into lightguide <NUM> and propagates through protective area <NUM>. At least part of the light is then coupled out at primary outcoupler <NUM>.

If the lightguide is undamaged, all or part of the primary outcoupler <NUM> will light up.

If any part of protective area <NUM> has been damaged, some light will typically fail to arrive at primary outcoupler <NUM> 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 <NUM>, which again can be used to detect the presence of the damage.

The overlap between protective area <NUM> and personalized area <NUM> should be large enough to effectively cover a macroscopic part of personalized area <NUM>. Hence, the overlap between protective area <NUM> and the personalized information 22a, 22b, <NUM>, <NUM>, <NUM> in protective area <NUM> is advantageously at least <NUM><NUM>, in particular at least <NUM><NUM>.

In order to be able to protect a macroscopic region, the distance between primary incoupler <NUM> and primary outcoupler <NUM> should be large. Hence, in a direction X between primary incoupler <NUM> and primary outcoupler <NUM>, protective area <NUM> advantageously has an extension L of at least <NUM>, in particular of at least <NUM>.

Advantageously, the extension of primary outcoupler <NUM> should be large enough to monitor a wide section of the personalized information <NUM> - <NUM>. Hence, in a direction Y perpendicular to direction X, primary outcoupler <NUM> has an extension W of at least <NUM>, in particular of at least <NUM>.

As seen in <FIG>, lightguide <NUM> may, in one embodiment, cover the personalized information, such as the writing 22a, 22b, and/or <NUM>, the photograph <NUM>, and/or the data carrier <NUM>, i.e. it is arranged above the personalized information. Thereby, it renders it difficult to gain access to said information from the top side <NUM> of the identification document, effectively securing the personalized information.

In another embodiment, which is shown in <FIG>, lightguide <NUM> may be arranged below the personalized information, such as the writing 22a, 22b, and/or <NUM>, the photograph <NUM>, and/or the data carrier <NUM>. Thereby, it renders it difficult to gain access to said information from the bottom side <NUM> of the identification document. In that case, a transparent layer <NUM> may e.g. be provided above primary incoupler <NUM> and primary outcoupler <NUM> and, optionally, between the personalized information <NUM> - <NUM> and lightguide <NUM>. 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.

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

As shown, a transparent layer <NUM> may e.g. be arranged between the first and second primary lightguides 12a, 12b.

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.

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 <NUM>, in particular of at least <NUM>. This allows to separately monitor the integrity of the protective areas <NUM> of the two lightguides 12a, 12b when both are illuminated at the same time.

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

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.

In the embodiments of <FIG>, primary incoupler <NUM> and primary outcoupler <NUM> are both arranged laterally outside personalized area <NUM>.

In particular, primary incoupler <NUM> is arranged laterally outside a first edge <NUM> on a first side of personalized area <NUM>, i.e. it does not overlap with any part of the personalized information <NUM> - <NUM> in personalized area <NUM>.

Similarly, primary outcoupler <NUM> is arranged laterally outside a second edge <NUM> on a second side of personalized area <NUM>, i.e. it does not overlap with any part of the personalized information <NUM> - <NUM> in personalized area <NUM>.

Edges <NUM> and <NUM> may be opposite to each other.

However, primary incoupler <NUM> and/or primary outcoupler <NUM> may also overlap with personalized area <NUM>, in particular with the personalized information <NUM> - <NUM> in personalized area <NUM>.

Said overlap is advantageously small in order to prevent primary incoupler <NUM> and/or primary outcoupler <NUM> from affecting the visibility of the personalized information. Hence, advantageously, primary incoupler <NUM> and/or primary outcoupler <NUM> overlap with no more than <NUM>%, in particular with no more than <NUM>%, of the personalized area <NUM>, in particular of the area of the personalized information <NUM> - <NUM>.

Advantageously, though, in this case, primary incoupler <NUM> and/or primary outcoupler <NUM> is/are not arranged completely within personalized area <NUM> but overlap with an edge <NUM>, <NUM> thereof.

<FIG> shows an example where primary outcoupler <NUM> overlaps edge <NUM> of personalized area <NUM> as well as an edge of at least one of the personalized information <NUM> - <NUM>.

Similarly, and in addition or alternatively thereto, incoupler <NUM> may at least partially overlap personalized area <NUM>, and in particular at least one of the personalized information <NUM> - <NUM>, as indicated by a dotted primary incoupler <NUM>' in <FIG>.

In the embodiments shown so far, there are no incoupling or outcoupling structures within protective area <NUM>. This renders protective area <NUM> basically invisible, which provides excellent visibility of the information in personalized area <NUM>.

In another embodiment, though, lightguide <NUM> may comprise a secondary outcoupling structure <NUM>, in addition to primary outcoupler <NUM>, which is also able to couple light out from lightguide <NUM>. This secondary outcoupling structure <NUM> may be arranged in protective area <NUM>, as illustrated in <FIG>.

In that case, however, secondary outcoupling structure <NUM> is advantageously sparse, as defined above, in order to prevent a large loss of guided light in protective area <NUM> and/or to not obstruct the personalized information <NUM> - <NUM>. In other words, outcoupling structure <NUM> covers no more than <NUM>%, in particular no more than <NUM>%, of protective area <NUM>.

In addition, and as illustrated in <FIG>, any point P within protective area <NUM> should be close to at least part of outcoupling structure <NUM>. Advantageously, any such point P has a distance d of less than L/<NUM>, in particular of less than L/<NUM>, in particular less than L/<NUM>, in particular less than L/<NUM>, from the closest part of secondary outcoupling structure <NUM>.

This design ensures that no point P on protective area <NUM> is far away from secondary outcoupling structure <NUM>. Hence, any attempt to counterfeit or forge a macroscopic region of the identity document, for example, such as by removing lightguide <NUM> 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 <NUM>. This can be detected easily by sending light into lightguide <NUM> by means of primary incoupler <NUM> and by optically verifying secondary outcoupling structure <NUM>.

Primary and/or secondary outcoupling structure <NUM>, <NUM> may comprise at least one line-shaped element <NUM>. In this context, 'line-shaped' means that the line-shaped element <NUM> extends along straight or curved line as e.g. shown in <FIG>. Using line-shaped elements has the advantage that they are easily recognized by the eye without requiring a large amount of light.

For example, primary and/or secondary outcoupling structure <NUM>, <NUM> may form a guilloche pattern.

Line-shaped element <NUM> 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 <NUM>, in particular at least <NUM>, and/or width w is no more than <NUM>, in particular no more than <NUM>, in particular no more than <NUM>.

On the other hand, though, width w is advantageously at least <NUM>, advantageously at least <NUM>, in order to make the outcoupler well visible to the unaided eye.

Advantageously, there is a plurality of such line-shaped outcouplers, in particular at least <NUM>, in particular at least <NUM>, in particular at least <NUM>, which allows to distribute them over the protective area for better protection and visual detection.

The shape of the primary and/or secondary outcoupling structure <NUM>, <NUM> may vary. The may e.g. also form dots, symbols, characters, etc..

<FIG> also shows, in enlarged fashion, a diffractive grating <NUM> that can be used to couple light out from lightguide <NUM>.

Advantageously, secondary outcoupling structure <NUM> overlaps with at least part of the personalized information <NUM> - <NUM>.

<FIG> show an embodiment where primary incoupler <NUM> and/or primary outcoupler <NUM> is/are arranged at windows <NUM>, <NUM> of the document.

These windows <NUM>, <NUM> are designed to be transparent for at least one wavelength that is coupled in/out by primary incoupler <NUM> and primary outcoupler <NUM>, respectively. In this context, "transparent" advantageously designates that at least <NUM>%, in particular at least <NUM>%, in particular at least <NUM>%, of the light at said wavelength are transmitted through carrier <NUM> at the location of the window, advantageously without being scattered.

This has the advantage that light may be coupled in from the top or the bottom of the document, at primary incoupler <NUM> and/or at primary outcoupler <NUM>.

In the embodiment of <FIG>, two such windows <NUM>, <NUM> are provided, with first window <NUM> being located at primary incoupler <NUM> and second window <NUM> being located at primary outcoupler <NUM>.

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

Protective area <NUM> again may cover at least part of personalized area <NUM>, such as e.g. photograph <NUM> as shown.

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

However, advantageously, personalized area <NUM> at least includes any photograph <NUM> of the owner and at least one instance of the name data 22a, 22b of the owner, and preferably also any data carrier <NUM> with owner-specific information.

In order to distribute the light from a single light source over a large protective area <NUM>, primary incoupler <NUM> advantageously spreads the light it couples into lightguide <NUM>. Advantageously, it is structured to generate a fan of light in lightguide <NUM> that has an angular width of at least <NUM>°, advantageously at least <NUM>°. In this context, the width of the fan is defined by the angular range over which the guided light varies within <NUM>% of the maximum intensity.

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

In addition or alternatively thereto, primary incoupler <NUM> advantageously spreads the light it couples into lightguide <NUM> to illuminate all of the extension W of primary outcoupler <NUM> (which is e.g. the extension along direction Y in <FIG>) with a variation of intensity of <NUM>% or less over the whole extension W.

In the embodiment of <FIG> protective area <NUM> covers all of the writing for name data 22a, 22b, the writing <NUM> for date of birth, and the data carrier <NUM>. However, it only covers part of photograph <NUM>.

In general, protective area <NUM> advantageously overlaps with all or at least <NUM>%, in particular at least <NUM>% of every personalized information in personalized area <NUM>. For example, it may cover photograph <NUM> fully and/or any other personalized information only partially.

Primary incoupler <NUM> and/or primary outcoupler <NUM> may be adapted to respectively in/out couple light from/to below document, provided the carrier <NUM> 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.

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 <NUM>, i.e. into the lightguide.

The primary outcoupler structure <NUM> may represent at least part of the portrait of the owner of the identification document. In other words, outcoupler structure <NUM> 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 <NUM>.

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.

The primary incoupler <NUM> 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.

In the embodiments above, neither primary incoupler <NUM> nor primary outcoupler <NUM> are completely arranged within the personalized area <NUM>.

<FIG>, in contrast thereto, shows an embodiment where with primary incoupler <NUM> and primary outcoupler <NUM> are arranged completely within personalized area <NUM>.

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

Protective area <NUM> may comprise at least one further visual security element, in addition to the outcoupler structures. Such a security element <NUM> is shown, by way of example, as a dotted cross in <FIG>. 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.

Lightguide <NUM> may be a foil manufactured apart from carrier <NUM> and then laminated thereto, or it may also be formed in-situ on carrier <NUM>.

Any incoupler and/or outcoupler mentioned herein may e.g. be a diffractive incoupler/outcoupler, a fluorescent incoupler/outcoupler, an Infrared Up-converting 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 <NUM>), diffusing or scattering structures or materials.

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.

As illustrated by way of example in <FIG>, lightguide <NUM> 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.

Claim 1:
A document of identification having
a personalized area (<NUM>) carrying personalized information (<NUM> - <NUM>) identifying an owner of the document and
an optical lightguide (<NUM>) comprising a primary incoupler (<NUM>) and a primary outcoupler (<NUM>),
wherein the lightguide (<NUM>) forms a protective area (<NUM>) between said primary incoupler (<NUM>) and said primary outcoupler (<NUM>), wherein said protective area (<NUM>) overlaps with at least part of said personalized area (<NUM>)
characterized in that said primary incoupler (<NUM>) is located laterally at a first side of said personalized area (<NUM>).