Multilayer data storage device having a flat see-through window

Abstract

The present invention relates to a multilayer data carrier (40) having an areal see-through window (42), having an opaque core layer (20) that is provided in a sub-region with an areal gap (22) to form the see-through window (42), and two cover foils (24, 26) that are transparent at least in the region of the see-through window (42) and that are laminated onto opposing sides of the opaque core layer (20). Here, according to the present invention, it is provided that the two cover foils (24, 26) are joined with each other across the entire area of the see-through window (42) and that the cover foils (24, 26) that are joined with each other are provided in the see-through window (42) with an embossed relief pattern (44), the embossed relief pattern (44) producing in the see-through window (42) a latent image that, due to light diffraction, comes into view when looked through.

Claims

1. A multilayer data carrier having an areal see-through window, comprising: an opaque core layer that is provided in a sub-region with an areal gap to form the see-through window, and two cover foils, wherein each cover foil constitutes a single layer or a single material and that are transparent at least in the region of the see-through window and that are laminated onto opposing sides of the opaque core layer wherein the two cover foils coalesce with each other across the entire areal gap, characterized in that the data carrier is an identification card or a data page for an identification document the two cover foils are joined with each other across the entire area of the see-through window by laminating the cover foils with the aid of opposing lamination plates, and the cover foils that are joined with each other are provided in the see-through window with an embossed relief pattern, which is produced by a relief pattern in at least one lamination plates, which is elevated in at least some regions, and the embossed relief pattern producing in the see-through window a latent image that, due to light diffraction, comes into view when looked through, and that is substantially non-visible in reflected light.

2. The data carrier according to claim 1, characterized in that the see-through window is developed to have a large area having an area of more than 1 cm.sup.2.

3. The data carrier according to claim 1, characterized in that the see-through window is developed to have a smallest dimension of more than 0.5 cm.

4. The data carrier according to claim 1, characterized in that the embossed relief pattern forms a geometric pattern, a three-dimensional motif or a microtext.

5. The data carrier according to claim 1, characterized in that the see-through window further includes a marking produced due to the influence of laser radiation.

6. The data carrier according to claim 5, characterized in that the embossed relief pattern and the laser-produced marking are associated in meaning.

7. The data carrier according to claim 6, characterized in that the embossed relief pattern and the laser-produced marking each constitute pieces of information that are related to or that complement each other.

8. A method for manufacturing a multilayer data carrier having an areal see-through window, in which an opaque core layer is provided and, to form the see-through window, is provided in a sub-region with an areal gap, a first cover foil and a second cover foil, wherein each cover foil constitutes a single layer or a single material are provided that are transparent at least in the region of the see-through window to be produced, and a layer sequence composed of the first cover foil, the opaque core layer and the second cover foil are laminated together with the aid of opposing lamination plates under the influence of temperature and pressure such that the two cover foils coalesce with each other across the entire areal gap such that the areal gap in the core layer, together with the transparent regions of the cover foils, forms the see-through window, characterized in that the data carrier is an identification card or a data page for an identification document, at least one of the lamination plates comprises, in the region of the see-through window, a relief pattern that is elevated in at least some regions, and whose form, upon lamination, is transferred in the inverse form to the adjacent cover foil, and whose elevations, upon lamination, produce an additional contact pressure in the interior of the areal gap in the core layer.

9. The method according to claim 8, characterized in that the transferred relief pattern produces in the see-through window a latent image that, due to light diffraction, comes into view when looked through.

10. The method according to claim 8, characterized in that a marking is produced in the see-through window due to the influence of laser radiation.

Description

(1) Further exemplary embodiments and advantages of the present invention are explained below by reference to the drawings, in which a depiction to scale and proportion was dispensed with in order to improve their clarity.

(2) Shown are:

(3) FIG. 1 schematically, the manufacture of a data page having a see-through window according to a method in the background art,

(4) FIG. 2 a data page manufactured with the conventional method in FIG. 1 and having a lamination mark in the center of the window,

(5) FIG. 3 schematically, the manufacture of a data page having a see-through window according to an inventive method,

(6) FIG. 4 manufactured with the method of FIG. 3, a data page according to an exemplary embodiment of the present invention,

(7) FIG. 5 a data page having opposing embossed relief patterns in the see-through window according to another exemplary embodiment of the present invention, and

(8) FIG. 6 a data page having an additional laser-produced marking according to a further exemplary embodiment of the present invention.

(9) The present invention will now be explained using the example of cards having see-through windows, for example a data page for a passport. For a better understanding of the present invention, first, with reference to FIGS. 1 and 2, a conventional method for manufacturing a data page 10 having a see-through window 12 and the problems that often occur here are outlined.

(10) In the conventional method, a temperature-stable opaque core layer 20 is provided and, in a sub-region, provided with an areal gap 22 in the shape of the desired see-through window 12. Further, two cover foils 24, 26 are provided that are transparent at least in the region of the subsequent see-through window 12. The first cover foil 24, the core layer 20 and the second cover foil 26 are laid one on top of the other (for the sake of clarity, FIG. 1 shows the layers having a small separation) and, with the aid of two opposing lamination plates 30, laminated together under the influence of pressure 32 and temperature.

(11) Upon lamination, the material of the cover foils 24, 26 softens, flows into the areal gap 22 in the core layer 20 and fills said gap, such that a card structure having a smooth surface and a see-through window 12 in the region of the gap 22 is created.

(12) In practice, however, it has been shown that said method delivers satisfactory results only for small see-through windows. For larger-area see-through windows, in contrast, particularly in the center region of the see-through window, distracting marks are often observed that, according to current understanding, can be attributed to an incomplete lamination of the cover foil material that coalesces in the window region 14 and the inclusion of air bubbles 16 in the window region. According to said understanding, particularly in the center region of large-area windows, the coalescing materials of the cover foil then only lie next to each other and are not joined with each other.

(13) The inventive method described with reference to FIGS. 3 and 4 for manufacturing a data page 40 having a see-through window 42 provides effective relief here.

(14) In the method according to the present invention, a temperature stable opaque core layer 20 is provided and, in a sub-region, provided with an areal gap 22 in the shape of the desired see-through window 42. For this, the gap 22 can, for example, be punched out of the core layer. Since, due to the inventive approach, no distracting lamination marks occur, as explained below, the area of the gap 22 can be chosen practically arbitrarily, especially also to have a large area.

(15) In addition to the core layer 20, two cover foils 24, 26 are provided that are transparent at least in the region of the subsequent see-through window 42. The first cover foil 24, the core layer 20 and the second cover foil 26 are laid one on top of the other (for the sake of clarity, FIG. 3 shows the layers having a small separation) and, with the aid of two opposing lamination plates 50, 52, laminated together under the influence of pressure 32 and temperature.

(16) Here, at least one of the lamination plates 50 is provided, in the region of the see-through window 42 to be produced, on the side facing the layers to be laminated, with a relief pattern 54 that, at least in sub-regions, rises above the height level of the area of the lamination plate 50 that lies outside the relief pattern 54. Here, the terms elevation and depression refer, independently of the orientation of the lamination plate in space, to the surface of the lamination plate 50 facing the layers to be laminated. A pattern protruding from the surface is referred to as an elevation, and a receding pattern as a depression.

(17) The relief pattern 54 can comprise both elevations and depressions, it is only important that elevations, that is, protruding patterns, are present at least in a sub-region of the relief pattern 54.

(18) Here, the elevations and, if appropriate, also depressions in the relief pattern are arranged in the form of a desired motif, in the exemplary embodiment for instance in the form of a microtext.

(19) Upon lamination, the relief pattern 54 in the lamination plate 50 now effects two things. First, upon lamination, the elevations in the relief pattern 54 produce an additional contact pressure in the interior of the areal gap 22 in the core layer 20. When the softened cover foil material coalesces, this additional contact pressure significantly supports the joining of the materials especially in the center of the window region 46 and, in this way, effectively prevents the inclusion of air bubbles, and thus the creation of distracting lamination marks, also in large-area windows.

(20) Second, upon lamination, the relief pattern 54 is transferred in the inverse form to the adjacent cover foil 26, such that an embossed relief pattern 44 is created there that, in the exemplary embodiment, forms, for instance, a microtext. In this way, there is created in the see-through window 42 an additional security feature that further increases the counterfeit security of the data page 40.

(21) The embossed relief pattern 44 forms, in the see-through window 42, a latent image that, similar to a watermark, is practically non-visible in top view and, due to light diffraction, comes into view only when looked through.

(22) FIG. 5 shows, as a further exemplary embodiment, a data page 60 having a see-through window 62. Upon manufacturing the data page 60, in the lamination step, lamination plates having a relief pattern that is elevated in at least some regions were used on both sides, such that the see-through window 62 was provided on both sides with, in each case, an embossed relief pattern 64, 66. The opposing relief patterns 64, 66 can be identical or different and complement each other, for example, to form a complete motif when looked through from a certain viewing angle. Since the images of the relief patterns 64, 66 are created in different planes, also a particularly strong three-dimensional impression can be produced. In the case of identical relief patterns 64, 66, the congruence of the relief pattern motifs when looked through from a certain viewing direction can be used as a further authenticating feature.

(23) The embossed relief pattern of the see-through window can be combined with further authenticating features, such as a laser personalization. For this, the exemplary embodiment in FIG. 6 shows a data page 70 of a passport having a see-through window 72 in which, upon lamination, a relief pattern 74 was embossed in the manner described above. In addition, the see-through window 72 includes a marking 76 that, due to the influence of laser radiation, was inscribed in the cover foil material that coalesced in the window region. The marking 76 advantageously displays personal data and constitutes, for example, a photo of the passport holder.

(24) The laser-produced marking 76 and the embossed relief pattern 74 can be coordinated with each other in such a way that, when viewed in transmitted light, in combination, they produce a certain pattern that can be visually or machine-checked. Due to the different manufacturing routes, such security elements of different types that are related to or that complement each other are very difficult to imitate. In this way, the embossed relief pattern 74 produces an additional protection of the laser-produced marking 76 of the see-through window 72.

LIST OF REFERENCE SIGNS

(25) 10 Data page 12 See-through window 14 Window region 16 Air bubbles 20 Opaque core layer 22 Areal gap 24, 26 Cover foils 30 Lamination plates 32 Influence of pressure 40 Data page 44 Embossed relief pattern 42 See-through window 46 Window region 50, 52 Lamination plates 54 Relief pattern 60 Data page 62 See-through window 64, 66 Relief patterns 70 Data page 72 See-through window 74 Relief pattern 76 Laser-produced marking