The present invention relates to an identity document having a part in which an identifying photograph/image is incorporated.

Such an identity document is generally known in the state of the art. This can be a passport with cover, identity page affixed within and visa pages, as well as identification in the form of a card, such as a debit card, driving licence, credit card etc.

Such documents are continually being further protected against misuse by the addition of ever more safety features thereto.

It is assumed that as a result of applying a large number of different safety features manipulation of such identity documents becomes increasingly more difficult.

Some governments have recently imposed the requirement that the identity document must have characteristics of the holder stored in electronic form. Such characteristics can be characteristics of the iris of (the eye of) the holder, his/her appearance and the like.

Some governments are now giving preference to the use of one or more fingerprints for identification. The aim is to store the fingerprint concerned in a chip, mounted in the identity document, possibly in an encrypted manner. The contents of the chip are read at the time of identification and compared with the actual fingerprint of the holder of the card. During this operation a decryption operation possibly also takes place in order to be able to compare the encrypted information with the actual fingerprint.

In the case of theft the new holder will, with malicious intent, be interested in the fingerprints of the legitimate holder in order thus to be able to identify him/herself illegally using these legal fingerprints.

To prevent problems it is proposed to store two fingerprints, from the left and right hand, in the system. By this means it is more difficult for the person bent on misuse to take fingerprints from the user. However, it is important that the identity document concerned is also protected as far as possible.

DE 2937906 discloses a method for storing personal data such as fingerprints on a magnetic strip.

EP 0 832 756 describes an identity card made up of a laminate in which a relief is applied in order to obtain an improved appearance of the card with regard to gloss and the like. The roughening is used to improve the laminated effect. The final structure is not provided with roughening.

US 2004/0 140 665 discloses a card provided with surface elevations which form lens structures to obtain optical effects.

The aim of the present invention is to promote the security of the identity document in general.

This aim is realised with an identity document as described above in that this has a support with, incorporated therein, a chip that can be read externally and contains readable information with regard to fingerprints stored therein, wherein the surface of said support and/or said card-shaped part is provided with a ripple structure, comprising raised and lowered parts, wherein the distance (a) between two adjacent raised parts is 800 - 1400 μm. According to the present invention the structure of the identity document is chosen such that no fingerprints of the user easily appear thereon which could be copied for identification in the case of theft of the document.

The distance of 800 - 1400 μm described above corresponds to the range of two raised parts in a fingerprint pattern. Because of crossing of the ripple structure and the fingerprint an irregular fingerprint is produced on the document that is so imperfect that this cannot be used for subsequent identification purposes.

The ripple structure concerned is preferably applied to the transparent surface layer of the identity page, under which the photograph is mounted. This is in general a smooth plastic layer on which fingerprints can remain particularly easily. By now providing said part with the ripple structure according to the invention it is no longer possible to take perfect fingerprints therefrom.

Furthermore, the ripple structure can be used in other locations in the identity document. In this context the cover, any visa pages and the like may be mentioned.

The ripple structure can be built up in various ways. This can consist of parallel lines that delimit the raised and lowered parts. It is also possible to apply groups of parallel lines, which groups cross one another. Another possibility is to apply convex parts or pyramid parts or other elevations.

The difference in height between the raised part and lowered part is approximately 5 % of the distance between them. That is to say, if the distance between two adjacent raised parts is approximately 1000 μm, the height is at least 50 μmbut can, of course, be more.

The ripple structure described above can be produced by applying the ripple structure concerned during the final embossing process for producing the document concerned. It is

also possible to carry this out in the laminating plate when laminating, for example, the photograph and/or chip in a card. Another possibility is the provision of material for producing the identity document that is provided with the ripple structure.

The invention will be explained in more detail below with reference to an illustrative embodiment shown in the drawing. In the drawing:

Fig. 1 shows, diagrammatically, a passport according to the invention;

Fig. 2 shows an identity part according to the invention;

Fig. 3 shows, in detail, the surface structure of the part circled in Fig. 2, in cross- section;

Fig. 4 shows an alternative surface structure in plan view; and

Fig. 5 shows a further alternative structure in plan view.

In Fig. 1 a passport or other identity document is indicated in its entirety by 1. This consists of a cover 2, in which an identity page 3 is affixed. Visa pages are indicated by 4. In the embodiment according to Fig. 1 a chip 5 is mounted in the cover, which chip cannot be removed therefrom without damaging the document. It is also possible to mount the chip concerned either in one of the visa pages 4 or in the identity page 3.

An identity card 10 is shown in Fig. 2. A chip 12, as well as a photograph 11, are also incorporated therein.

For both the documents described above it is the case that the chip 5, 12 concerned contains information with regard to the user's fingerprint. This information can be incorporated in encrypted or non-encrypted form. At the time of identification a scan has to be made of the actual fingerprint of the bearer of the document and this must be compared with the information stored in the chip 5, 12.

In order to prevent that, in the event of theft, the person of ill will can take fingerprints of the legal holder from the document 1, 10, it is proposed to provide this document with a surface structure as shown in Fig. 3. This structure can be applied to both sides of the part. Fig. 3 is a detail of a cross-section of the top of the top layer of the document 10 close to the photograph 11. It can be seen from this that the top surface of the top layer of the document 10 is provided with a ripple structure 17. This ripple structure 17 is undulating and consists of peaks 15 and troughs 16. The distance between two peaks (or two troughs) is indicated by (a). According to the present invention the distance a is preferably between 800 and 1400 μm and more particularly approximately 1000 μm. The height (h), that is to say the difference in height between a peak 15 and a trough 16 is

around at least approximately 5 % of the distance (a).

In other words, in a preferred embodiment, the distance (a) is approximately 1000 μm and the height at least approximately 50 μm. It will be understood that a greater height is possible. After all, the aim of the present invention is to prevent a perfect fingerprint remaining on the undulating structure 17. To this end the frequency of the peaks 15 and troughs 16 is so chosen that this corresponds to the frequency of the peaks and troughs of an average fingerprint, as a result of which when this undulating structure is grasped only a highly fragmented fingerprint remains which is completely unsuitable for scanning for identification purposes.

In Fig. 3 the undulating structure is shown as a group of continuous lines. Alternatives are indicated in Figs 4 and 5. In Fig. 4 a pyramid-like structure is shown by 20, whilst in Fig. 5 a structure with hemispheres is shown. These can easily be applied by stamping, pressing or embossing in the plastic material or the plastic cover of the document before, during or after combining the various layers.

Apart from on the card 10, the structure described above can also be on the cover or on the visa pages of an identity document.

Although the invention has been described above with reference to a preferred embodiment, those skilled in the art will immediately understand that variants are possible within the scope of the appended claims, for which explicit rights are requested.