Diffractive Security Element with Individualized Code

• US 20090072526A1
• Filed: 09/09/2008
• Published: 03/19/2009
• Est. Priority Date: 09/19/2007
• Status: Active Grant

• Current Assignee: OVD Kinegram AG (Leonhard KURZ Stiftung & Company KG)
• Original Assignee: OVD Kinegram AG (Leonhard KURZ Stiftung & Company KG)
• Inventors: Tompkin, Wayne Robert, Schilling, Andreas, Peters, John Anthony
• Granted Patent: US 8,308,197 B2
• Time in Patent Office: Days
• US Class Current: 283/85
• CPC Class Codes: B42D 25/328 Diffraction gratings; Holograms
• CPC Class Codes: B42D 25/41 using electromagnetic radiation B42D25/435 takes precedence

Abstract

Described is a security element for increasing the forgery-proof nature of a security document, in particular an identity card or pass, a passport or an identification card. The security element (1) has a first diffractive region (15) having an open code which is visible with a naked eye. The first diffractive region further has a concealed code which is not visible with the naked eye and which can be reconstructed from the arrangement of diffractive microregions disposed in the first region (1) and/or from the structure of the first diffractive region (1). Further described is a method of increasing the forgery-proof nature of a security document.

Claims

1. A security element for increasing the forgery-proof nature of a security document, wherein

the security element has a first region in which there is shaped at least region-wise in a layer of the security element a diffractive surface relief which is provided at least region-wise with a reflection layer and which shows an open item of information visible with a naked eye and the first region further has a concealed code which is not visible with the naked eye and which can be read out optically and which is machine-readable and which is formed from an arrangement of microregions which are arranged in the first region and which differ optically from the surrounding region and in which a surface relief differing from the surrounding region is shaped and/or the reflection layer is removed and/or the machine-readable code is generated by the surface relief which is shaped into the layer.

2. A security element as set forth in claim 1, wherein the concealed code is a code which is individualized by means of a laser.

3. A security element as set forth in claim 1, wherein the surface area occupied by the microregions in the first region is constant in relation to each surface area region of 300 μ

m×

300 μ

m.

4. A security element as set forth in claim 1, wherein the microregions are of a surface area extent in the range of between 10 μ

m×

10 μ

m and 30 μ

m×

30 μ

m.

5. A security element as set forth in claim 1, wherein there are not more than between 100 and 1000 microregions/mm² in the first region.

6. A security element as set forth in claim 1, wherein the concealed code is determined by the arrangement of the microregions.

7. A security element as set forth in claim 1, wherein a hologram is shaped into the layer in the first region in the form of a surface relief, showing the concealed machine-readable code only upon irradiation with monochromatic coherent light of a predefined wavelength.

8. A security element as set forth in claim 7, wherein the hologram appears as a matt structure upon illumination with polychromatic light.

9. A security element as set forth in claim 1, wherein two or more diffractive structures are shaped as the surface relief into the layer in the first region.

10. A security element as set forth in claim 1, wherein the open code is introduced into the first region by a laser engraving operation by the reflection layer being removed in the region of the code.

11. A method of increasing the forgery-proof nature of a security document, in particular an identity card, a passport or an identification card, wherein

a security element is provided which has a first region in which there is shaped at least region-wise into a Sayer of the security element, a diffractive surface relief which is provided at least region-wise with a reflection layer and which shows an open item of information which is visible with a naked eye, wherein the first region further has a concealed code which is not visible with the naked eye and which can be optically read out and which is machine-readable and which is formed from an arrangement of microregions which are arranged in the first region and which differ optically from the surrounding region and in which a surface relief differing from the surrounding region is shaped and/or the reflection layer is removed and/or the machine-readable code is generated by the surface relief which is shaped into the layer, and the concealed machine-readable code is read out with a reading device for verification of the security element.

12. A method as set forth in claim 11, wherein the open information is also read out by means of the reading device, wherein the open information which is visible with a naked eye is an open, optically machine-readable individualized code.

13. A method as set forth in claim 11, wherein the open information and/or the concealed code are compared to a data set stored in a database.

14. A method as set forth in claim 13, wherein the open code and/or the concealed code is generated upon individualization of the security element as an individualized code, and is written into the first region of the security element, and the individualized code is stored in the database and the database is queried for verification of the security element.

15. A reading device for carrying out the method as set forth in claim 11, wherein

the reading device comprises at least the following components:

a transparent carrier plate on which the security element can be placed on its front side,

a camera which is so arranged and oriented that it produces an image of the front side of the security element which is resting on the transparent carrier plate,

a polychromatic non-collimated light source arranged beneath the carrier plate, and

a monochromatic coherent or semi-coherent point light source, wherein the point light source is arranged beneath the carrier plate and is so oriented that the optical axis of the point light source impinges at an angle of between 45° and

135°

, on the region of the carrier plate on which the security element can be placed.