Title:
Security Paper and a Method for the Production Thereof
Kind Code:
A1


Abstract:
The invention relates to a security paper for manufacturing security or value documents, such as banknotes, identification cards and the like, having at least two through openings (12, 16). According to the present invention, a first (12) of the through openings is produced during paper manufacture and exhibits characteristic irregularities in the edge region (14), while a second (16) of the through openings is produced after paper manufacture, by cutting or punching, having a sharply delimited edge region (18).



Inventors:
Ruck, Jurgen (Schliersee, DE)
Heim, Manfred (Munchen, DE)
Pretsch, Andreas (Holzkirchen, DE)
Application Number:
11/913658
Publication Date:
09/11/2008
Filing Date:
05/03/2006
Assignee:
GIESECKE & DEVERIENT GMBH (Munich, DE)
Primary Class:
Other Classes:
162/109
International Classes:
D21H27/22
View Patent Images:



Primary Examiner:
FORTUNA, JOSE A
Attorney, Agent or Firm:
Leydig, Voit & Mayer, Ltd. (GS BOULDER) (Boulder, CO, US)
Claims:
1. A security paper for manufacturing security or value documents, such as banknotes, identification cards and the like, having at least two through openings, characterized in that a first of the through openings is produced during paper manufacture and exhibits characteristic irregularities in an edge region, and a second of the through openings is produced after paper manufacture, by cutting or punching, having a sharply delimited edge region, the contour shapes of the first and the second through opening being associated in meaning.

2. The security paper according to claim 1, characterized in that the contour shapes of the first and the second through opening constitute related or complementary information.

3. The security paper according to claim 2, characterized in that the information constitutes an image motif, characters or a code.

4. The security paper according to claim 1, characterized in that the second opening is produced by laser cutting.

5. The security paper according to claim 1, characterized in that the security paper exhibits a predefined paper thickness and a thin site having reduced paper thickness, the second through opening being introduced in the region of the thin site.

6. The security paper according to claim 5, characterized in that the thin site comprises a watermark.

7. The security paper according to claim 1, characterized in that the second opening is formed having edge surfaces that are tilted against the surface normal.

8. The security paper according to claim 7, characterized in that the second opening exhibits edge surfaces of varying tilt against the surface normal.

9. The security paper according to claim 1, characterized in that the two openings are closed on one side of the security paper with a foil element.

10. The security paper according to claim 1, characterized in that the two openings are closed on both sides of the security paper with a foil element.

11. A security paper for manufacturing security or value documents, such as banknotes, identification cards and the like, having at least one through opening, characterized in that the edge surface of the through opening exhibits first, sharply delimited subregions and second subregions having characteristic irregularities.

12. The security paper according to claim 11, characterized in that first and second subregions alternate along the contour line of the opening.

13. The security paper according to claim 12, characterized in that first and second subregions alternate along the contour line of the opening in irregular sequence.

14. The security paper according to claim 11, characterized in that first and second subregions each extend through the entire paper thickness.

15. The security paper according to claim 11, characterized in that first and second subregions succeed one another in one direction along the thickness of the security paper and complement each other to form the through opening.

16. The security paper according to claim 11, characterized in that the security paper exhibits a predefined paper thickness and a thin site having reduced paper thickness, the through opening being introduced in the region of the thin site.

17. The security paper according to claim 16, characterized in that the thin site comprises a watermark.

18. The security paper according to claim 11, characterized in that the first subregions are produced by laser cutting.

19. The security paper according to claim 11, characterized in that the first subregions are formed having edge surfaces that are tilted against the surface normal.

20. The security paper according to claim 19, characterized in that the first subregions exhibit edge surfaces of varying tilt against the surface normal.

21. The security paper according to claim 11, characterized in that the through opening is closed on one or on both sides of the security paper with a foil element.

22. A security paper for manufacturing security or value documents, such as banknotes, identification cards and the like, having at least one through opening, produced during paper manufacture, that exhibits characteristic irregularities in the edge region, characterized in that the through opening is combined with an engraving that is produced by laser etching and that complements the opening to form a projection representation.

23. The security paper according to claim 22, characterized in that the through opening is closed on one or on both sides of the security paper with a foil element.

24. A security paper for manufacturing security or value documents, such as banknotes, identification cards and the like, having an embedded foil element that is visible in subregions through window regions manufactured with papermaking technology, characterized in that the security paper exhibits, in the region of the foil element, an opening that is produced after paper manufacture, by cutting or punching, having a sharply delimited edge region, and that is disposed immediately next to the window regions manufactured with papermaking technology.

25. The security paper according to claim 24, characterized in that the sharply delimited opening is disposed over and/or immediately next to the foil element.

26. The security paper according to claim 24, characterized in that the sharply delimited opening is continuous, with the exception of a potential overlap region with the foil element.

27. The security paper according to claim 24, characterized in that the window regions are disposed on a first main surface of the security paper and the sharply delimited opening extends from the opposing main surface of the security paper to the foil element.

28. The security paper according to claim 24, characterized in that the foil element constitutes a security element, especially a security thread or a security band.

29. The security paper according to claim 24, characterized in that the sharply delimited opening is produced by laser cutting.

30. The security paper according to claim 24, characterized in that the security paper exhibits a predefined paper thickness and a thin site having reduced paper thickness, the sharply delimited opening being introduced in the region of the thin site.

31. The security paper according to claim 30, characterized in that the thin site comprises a watermark.

32. The security paper according to claim 24, characterized in that the sharply delimited opening is formed having edge surfaces that are tilted against the surface normal.

33. The security paper according to claim 32, characterized in that the sharply delimited opening exhibits edge surfaces of varying tilt against the surface normal.

34. The security paper according to claim 24, characterized in that the sharply delimited opening is closed on one or on both sides of the security paper with a foil element.

35. A method for manufacturing a security paper having at least two through openings, especially according to claim 1, in which during paper manufacture, a first through opening having characteristic irregularities is produced in the edge region, and after paper manufacture, a second through opening having a sharply delimited edge region is produced by cutting or punching, the first and second through opening being formed such that their contour shapes are associated in meaning.

36. The method according to claim 35, characterized in that a thin site having reduced paper thickness is formed in the security paper, and in that the second through opening is produced in the region of the thin site.

37. The method according to claim 35, characterized in that the second opening is produced by laser cutting.

38. The method according to claim 37, characterized in that the beam divergence and the beam tilt to the paper surface are set such that the second opening is produced having edge surfaces that are tilted against the surface normal.

39. The method according to claim 37, characterized in that the beam divergence and beam tilt to the paper surface are set such that the second opening is produced having edge surfaces that are tilted differently against the surface normal.

40. The method according to claim 35, characterized in that the two openings are closed on one or on both sides of the security paper with a foil element.

41. A method for manufacturing a security paper having at least one through opening, especially according to claim 11, in which the through opening is produced having an edge surface that exhibits first, sharply delimited subregions and second subregions having characteristic irregularities.

42. The method according to claim 41, characterized in that during paper manufacture, a through opening having characteristic irregularities is produced in the edge region, and after paper manufacture, the edge region of the produced opening is modified by cutting or punching and, in this way, is sharply delimited at least in subregions.

43. The method according to claim 42, characterized in that the modification is produced by laser cutting.

44. The method according to claim 41, characterized in that a piece of paper having the desired shape of the opening is defined with interrupted, sharply delimited cutting lines in the security paper, and the piece of paper is torn out of the security paper, especially blown out or pulled out.

45. The method according to claim 44, characterized in that the piece of paper is defined by laser cutting.

46. The method according to claim 41, characterized in that a sharply delimited thin site having the shape of the desired opening is produced in the security paper, and the piece of paper formed in the region of the thin site by the remaining paper thickness is torn out of the security paper, especially blown out or pulled out.

47. The method according to claim 46, characterized in that the sharply delimited thin site is produced by laser cutting.

48. The method according to claim 46, characterized in that the sharply delimited thin site is produced in the region of a thin site produced with papermaking technology, such as a watermark.

49. The method according to claim 43, characterized in that the beam divergence and beam tilt to the paper surface are set such that the modification, cutting line or thin site is produced having edge surfaces that are tilted against the surface normal.

50. The method according to claim 43, characterized in that the beam divergence and beam tilt to the paper surface are set such that the modification, cutting line or thin site is produced having edge surfaces that are tilted differently against the surface normal.

51. The method according to claim 41, characterized in that the through opening is closed on one or on both sides of the security paper with a foil element.

52. A method for manufacturing a security paper having at least one through opening, especially according to claim 22, in which during paper manufacture, a through opening having characteristic irregularities is produced in the edge region, and into the security paper is introduced, by laser etching, an engraving that complements the through opening to form a projection representation.

53. A method for manufacturing a security paper having an embedded foil element, especially according to claim 24, in which during paper manufacture, a foil element is embedded in the security paper, window regions are produced in which the foil element becomes visible, and after paper manufacture, an opening having a sharply delimited edge region is produced in the region of the foil element over and/or immediately next to the window regions by cutting or punching.

54. The method according to claim 53, characterized in that the sharply delimited opening is produced by laser cutting.

55. The method according to claim 53, characterized in that a through, sharply delimited opening is produced immediately next to the foil element.

56. The method according to claim 54, characterized in that the sharply delimited opening overlaps the foil element, the laser parameters being set such that the laser cuts only the paper substrate, but not the foil element.

57. The method according to claim 53, characterized in that, on a first main surface, prior to embedment, the foil element is coated contiguously with heat seal coating, and on a second, opposing main surface, is prepared with heat seal coating only at the foil edge, so that the middle region of the foil element remains uncoated.

58. The method according to claim 57, characterized in that the window regions are produced on the contiguously coated main surface.

59. The method according to claim 57, characterized in that the sharply delimited opening is produced in the middle region of the main surface that is coated only at the edge.

60. The method according to claim 57, characterized in that the sharply delimited opening is produced by laser cutting.

61. The method according to claim 60, characterized in that the beam divergence and beam tilt to the paper surface are set such that the sharply delimited opening is produced having edge surfaces that are tilted against the surface normal.

62. The method according to claim 60, characterized in that the beam divergence and beam tilt to the paper surface are set such that the sharply delimited opening is produced having edge surfaces that are tilted differently against the surface normal.

63. The method according to claim 53, characterized in that the sharply delimited opening is closed on one or on both sides of the security paper with a foil element.

64. A use of a security paper according to claim 1 for securing goods of any kind against counterfeiting.

65. A value document, such as a banknote, identification card and the like, having a security paper according to claim 1.

Description:

The present invention relates to a security paper for manufacturing security or value documents, such as banknotes, identification cards and the like.

For protection, security papers or value documents are often equipped with various authenticity features that permit the authenticity of the security paper or value document to be verified, and that simultaneously serve as protection against unauthorized reproduction.

For the purposes of the present invention, the term “security paper” refers to the unprinted paper that is typically present in quasi-endless form and is further processed at a later time. The term “value document” refers to a document that is finished for its intended use. For the purposes of the present invention, value documents are especially banknotes, stocks, bonds, certificates, vouchers, checks, valuable admission tickets and other papers that are at risk of counterfeiting, such as passports and other identification documents, as well as product protection elements, such as labels, seals, packaging and the like. In the following, the simplified designation “security paper” or “value document” includes all such documents and product protection means.

Publication WO 95/10420 describes a value document in which, after its manufacture, a through opening is punched that is subsequently closed on one side with a cover foil that overlaps the opening all around. The cover foil is transparent at least in a subregion so that, when an attempt is made to copy the value document, the background shows through and is rendered by the copier accordingly. In this way, counterfeits can easily be recognized. However, the opening produced by punching can likewise be produced by a counterfeiter. Although the color copy of a genuine value document no longer exhibits the transparent region, similar to the genuine value document, this region can be subsequently punched out and again closed with a suitable cover foil. Such counterfeits are difficult to recognize.

To remedy this, it is recommended in publication WO 03/054297 to produce a through opening already during paper manufacture. Such an opening produced at sheet formation exhibits, in the edge region, characteristic irregularities that are not subsequently manufacturable in the finished paper. The irregularities reveal themselves especially through the lack of a sharp cut edge or through irregular accretion of fibers in the edge region and through individual fibers that protrude into the opening. Such produced openings have a similarly high security value as a watermark produced at paper manufacture or a security thread embedded at paper manufacture.

However, such openings produced at paper manufacture often vary in their quality and are not easy to manufacture reproducibly. To some extent there is also the danger that fiber bundles partially close the opening.

Based on that, the object of the present invention is to create a security paper that avoids the disadvantages of the background art. In particular, the security paper is intended to combine the high counterfeit security of the openings produced at paper manufacture with high reproducibility at manufacture and good perceptibility of the authenticity features formed by the openings.

This object is solved by the features of the independent claims. Developments of the present invention are the subject of the dependent claims.

In a first aspect of the present invention, a generic security paper includes at least two through openings, a first of the through openings being produced during paper manufacture and exhibiting characteristic irregularities in the edge region, and a second of the through openings being produced after paper manufacture, by cutting or punching, having a sharply delimited edge region.

Here, the contour shapes of the first and the second through opening are preferably associated in meaning. In particular, it can be provided that the contour shapes of the first and the second through opening constitute related or complementary information, such as an image motif, characters or a code.

In a preferred embodiment, the second, sharply delimited opening is produced by laser cutting. Here, the sharply delimited edge surfaces of the second opening can run parallel and vertical to the paper surface. In contrast, in other embodiments, the second opening is formed having edge surfaces that are tilted against the surface normal. This can be achieved for example at laser cutting through a suitable selection of the beam divergence and the beam tilt relative to the paper surface. In particular, beam divergence and beam tilt to the paper surface can be set such that the second opening is produced having edge surfaces that are tilted differently against the surface normal. Tapered edges lead to a softer transition between a cover foil disposed over the openings and the paper substrate, and thus to, among other things, a lower susceptibility to dirt.

Moreover, differently tilted edge surfaces offer advantages in a duplex lamination of the opening with foils, and minimize especially the potential problem with air entrapment in duplex lamination. Furthermore, the openings having tilted edge surfaces exhibit an additional optical effect compared with vertical edge surfaces, since they appear to be of different sizes depending on the viewing direction.

In an advantageous development of the present invention, the security paper exhibits a predefined paper thickness and a thin site having reduced paper thickness, at least the second through opening being introduced in the region of the thin site. The thin site can especially comprise a watermark.

The two openings are expediently closed on at least one side of the security paper with a foil element. In some designs, the openings are even closed on both sides with a foil. Here, potential problems with air entrapment can be minimized through the above-mentioned tilted edges.

According to a further aspect of the present invention, a generic security paper includes at least one through opening, the edge surface of the through opening exhibiting first, sharply delimited subregions and second subregions having characteristic irregularities. First and second subregions preferably alternate along the contour line of the opening. In particular, it can be provided that first and second subregions alternate in irregular sequence along the contour line of the opening.

In one embodiment, first and second subregions each extend through the entire paper thickness. It can also be provided that first and second subregions follow one another in succession in one direction along the thickness of the security paper and complement each other to form the through opening. For example, in one edge section, sharply delimited subregions can extend through 90% of the paper thickness, while the edge surface for the remaining 10% of the paper thickness is irregular. Such edge sections can also be combined with other edge sections in which first or second subregions extend completely through the entire paper thickness.

Such a sequence of first and second subregions along the thickness of the security paper can be produced for example in that, during paper manufacture, a through opening having characteristic irregularities is produced in the edge region and, after paper manufacture, the edge region of the opening thus produced is modified by cutting or punching and, in this way, is sharply delimited at least in subregions. The modification is preferably produced by laser cutting, the above-mentioned possibilities for the tilt of the edge surfaces existing here, too.

The sequence of first and second subregions along the thickness of the security paper can also be produced, for example, in that a piece of paper having the desired shape of the opening is defined with interrupted, sharply delimited cutting lines in the security paper, and the piece of paper thus defined is then torn out of the security paper, especially blown out or pulled out. The piece of paper is preferably defined by laser cutting, the above-mentioned possibilities for the tilt of the edge surfaces again existing.

A further possibility to produce the sequence of first and second subregions consists in that a sharply delimited thin site having the shape of the desired opening is produced in the security paper, and in that the piece of paper formed in the region of the thin site by the residual paper thickness is torn out of the security paper, especially blown out or pulled out. Also, in a preferred method, the sharply delimited thin site is produced by laser cutting, if desired, having tilted edge surfaces, as explained above.

In an expedient embodiment, the security paper exhibits a predefined paper thickness and a thin site having reduced paper thickness, for example a watermark, the through opening being introduced in the region of the thin site.

The through opening is expediently closed on one or even on both sides of the security paper with a foil element.

In a further aspect of the present invention, a generic security paper includes at least one through opening, produced during paper manufacture, that exhibits characteristic irregularities in the edge region. The through opening is combined with an engraving, produced by laser etching, that complements the opening to form a projection representation. Preferably, the through opening is closed on one or even on both sides of the security paper with a foil element.

According to yet a further aspect of the present invention, a generic security paper includes an embedded foil element that is visible in subregions through window regions manufactured with papermaking technology. The security paper further exhibits, in the region of the foil element, an opening produced after paper manufacture, by cutting or punching, having a sharply delimited edge region.

In an advantageous embodiment, the sharply delimited opening is disposed over and/or immediately next to the foil element. Preferably, the sharply delimited opening is formed to be continuous, with the exception of a potential overlap region with the foil element.

According to a preferred embodiment, the window regions are disposed on a first main surface of the security paper, while the sharply delimited opening extends from the opposing main surface of the security paper to the foil element.

In all embodiments, the foil element can constitute a security element, especially a security thread or a security band.

The sharply delimited opening is advantageously produced by laser cutting. Here, the edge surfaces of the opening can be tilted, as explained above. In an expedient embodiment, the security paper exhibits a predefined paper thickness and a thin site having reduced paper thickness, for example a watermark, the sharply delimited opening being introduced in the region of the thin site. The sharply delimited opening is expediently closed on one or even on both sides of the security paper with a foil element.

The present invention also includes a value document, such as a banknote, an identification card and the like, having a security paper of the kind described. The security paper or value document according to the present invention can be used for securing goods of any kind against counterfeiting.

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 omitted in order to improve their clarity.

Shown are:

FIG. 1 a schematic diagram of a banknote composed of a security paper according to an exemplary embodiment of the present invention,

FIG. 2 a top view of a security paper according to another exemplary embodiment of the present invention,

FIGS. 3 and 4 further exemplary embodiments for inventive designs of two openings, associated in meaning, in a security paper,

FIG. 5 to 7 in each (a), an intermediate step in the manufacture of the security paper, shown in top view in each (b), according to further exemplary embodiments of the present invention

FIG. 8 in (a), an intermediate step in the manufacture of a security paper according to a further exemplary embodiment of the present invention, and in (b), a section of (a) after the removal of the cut-out shape,

FIG. 9 a top view of a security paper according to a further exemplary embodiment of the present invention,

FIG. 10 in (a), a top view of a security paper having an embedded foil element according to an exemplary embodiment of the present invention, and in (b) and (c), cross sections through the security paper in (a) along the lines B-B and C-C,

FIGS. 11 and 12 in each (a), a top view of a security paper having a foil element according to further exemplary embodiments of the present invention, and in (b) and (c), cross sections through the security paper in (a) along the lines B-B and C-C,

FIG. 13 a design in which a laser-cut opening is produced in the region of a thin site produced with papermaking technology,

FIG. 14 in (a) and (b), in cross section, two steps in the manufacture of a security paper according to a further exemplary embodiment of the present invention, and in (c), a top view of the security paper in (b),

FIG. 15 in (a) to (c), a diagram as in FIG. 14, the laser-cut opening being produced in the region of a thin site produced with papermaking technology, and

FIG. 16 in (a) and (b), two exemplary embodiments for laser-cut openings having edge surfaces that are tilted against the surface normal.

The invention will now be explained in greater detail using a banknote as an example. For this, FIG. 1 shows a schematic diagram of a banknote 10 that exhibits two through openings 12 and 16. Here, the first of the through openings 12 was produced during the manufacture of the security paper used for the banknote 10 and exhibits a fibrous, irregular edge region 14. Such an edge 14 is characteristic for the openings manufactured already at sheet formation and cannot be produced subsequently by punching or cutting the paper.

The second through opening 16 was produced only after paper manufacture by laser cutting or with the aid of a punching tool and exhibits a sharply delimited edge region 18. The two through openings 12 and 16 show the same information twice, spatially separated from each other, in each case an isosceles triangle in the exemplary embodiment in FIG. 1. It is understood that, instead of the triangle, also more complex shapes can be used, whose contours constitute, for example, a numeric string or a simple graphic.

Even if the information depicted by the first opening 12 should not be immediately perceptible due to its irregular edge region 14, due to the second opening 16 formed having clear contours, the viewer can establish the relationship of the two shapes and perceive the information with no doubt. Due to the presentation of the information twice in different attire, the attention and the regard of the viewer is guided particularly to the difference in the two openings. The high counterfeit security of the irregularly edged opening 12 is thus combined with the clear perceptibility of the sharply edged opening 16.

The section in FIG. 2 shows a top view of a security paper 20 according to a further exemplary embodiment of the present invention. The security paper 20 exhibits a first opening 22, produced with papermaking technology and having an irregular edge region 24, and a second opening 26 produced by laser cutting and having a sharp edge 28. Here, too, the contour shapes of the two openings 22 and 26 are associated in meaning. However, in contrast to the exemplary embodiment in FIG. 1, they do not present the same information, but form complementary parts of an aggregate piece of information.

Preferably, the depicted motif is matched to the different edge characteristics of the two openings. For illustration, FIG. 2 shows a flower motif in which the blossom is formed by the first, irregularly edged opening 22 and the stem and the leaves by the second, sharply edged opening 26. Since blossoms have very different and variable appearances in nature, the aggregate illustration seems very realistic. At the same time, due to the use of the two opening shapes, high counterfeit protection is ensured.

FIGS. 3 and 4 show further exemplary embodiments for designs in which the contour shapes of an irregularly edged first opening and a sharply edged second opening are associated in meaning.

The exemplary embodiment in FIG. 3(a) shows a sun in the shape of a circular, irregularly edged first opening 32 having rays that point radially outward and that are formed by laser-cut or punched triangular openings 34. In this exemplary embodiment, the rays formed by the second openings 34 constitute a motif that is dependent on the first opening. Also in FIG. 3(b), the irregularly edged, star-shaped first opening 36 constitutes a main motif on which the sharply edged, circular second openings 38 are graphically dependent.

FIG. 4 shows a further exemplary embodiment of the present invention, in which, in each case, the irregularly edged openings 42 and the sharply edged openings 44 complement each other to form the denomination “100” of a banknote 40. As usual, the denomination of the banknote is applied again, for example imprinted, clearly legibly in another location. In a real banknote, it is possible to use only one of the designs in FIG. 4, or both and, if applicable, further designs can be provided at various locations on the banknote.

An associated meaning of the two opening types can also result in that the irregularly edged opening is modified by the sharply edged opening, as will now be explained with reference to FIGS. 5 to 7. FIG. 5(a) shows a top view of a security paper 50 into which, at paper manufacture, initially a first, irregularly edged opening 52 was introduced. After paper manufacture, by laser cutting, the opening 52 is modified having two sharply edged openings 54 whose positions are drawn with dotted lines in FIG. 5(a).

After laser cutting, a single, continuous and through opening 56 results that, due to the two-phase manufacture, exhibits, as shown in FIG. 5(b), on the one hand, subregions 58 having an irregular edge, and on the other hand, subregions 59 having a sharp edge. Through such a modification, the edge characteristics of the two opening types can be combined in a single through opening.

In the exemplary embodiment in FIG. 6, in a first step at paper manufacture, an irregularly edged opening 62 in the shape of a predefined figure, for example in the shape of the four-arrow figure shown in FIG. 6(a), is produced in a security paper 60. The irregular edge region 64 in this figure is then partially recut with a laser. In this way, as illustrated in FIG. 6(b), a through opening 66 results that exhibits, on one hand, subregions 68 having an irregular edge and, on the other hand, subregions 69 having a sharp edge. Here, the relationship and the sequence of the subregions 68, 69 can be chosen freely.

FIG. 7 shows a further exemplary embodiment in which, as in the exemplary embodiment in FIG. 6, an irregularly edged opening 72 is first introduced into a security paper 70, as shown in FIG. 7(a). After paper manufacture, the opening 72 is completely recut with a laser (reference number 74), the size of the recut 74 being chosen to be somewhat smaller than the size of the opening 72. In this way, a through opening 76 is created that exhibits, in irregular sequence, subregions 78 having an irregular edge and subregions 79 having a sharp edge, as depicted in FIG. 7(b).

A sequence of regular and irregular edge regions can also be achieved without involvement of an opening already produced at paper manufacture. For example, with the aid of a laser, the desired shape of a through opening 82 can be cut out of a security paper 80 in such a way that the cutting lines 84 do not form a continuous cut curvature, but rather are interrupted by uncut sub-pieces 86, as shown in FIG. 8(a). The sub-pieces 86 form holding strips that initially prevent the removal of the cut-out shape.

The cut-out shape can subsequently be, for example, blown out with an air jet or pulled out by means of vacuum. As illustrated in section 85, depicted in detail in FIG. 8(b), in this approach, the cut-out piece of paper tears off irregularly at the holding strips 86, while the cutting lines 84 form sharp border edges. The edge region to the opening 82 thus exhibits a sequence of irregular subregions 88 and sharply cut subregions 89 whose relative size and sequence can be chosen almost freely through the cut control when laser cutting.

In the further exemplary embodiment of the present invention, shown in FIG. 9, the security paper 90 exhibits a through opening 92 produced during paper manufacture and having an irregular, fibrous edge. The opening 92 is combined with engraving lines 94 that are produced by laser etching. The engraving lines 94 are formed by locally thinned regions in the security paper 90, as described in publication WO 98/03348, whose disclosure in this respect is incorporated in the present description. According to the present invention, the position and arrangement of the engraving lines 94 are chosen such that they complement the opening 92 to form a projection representation.

When viewed in reflected light, the engraving lines 94 are practically imperceptible, the areal shape of the opening 92 determines the appearance there. If, in contrast, the security paper is viewed in transmitted light, due to the smaller paper thickness, the engraving lines 94 stand out clearly and complement the areal opening 92 to form a three-dimensional projection representation. In this way, the combination of the irregular opening 92 with the engraving lines 94 leads to an optically conspicuous interplay between the 2D and 3D depiction.

According to a further embodiment of the present invention, which will now be described with reference to FIGS. 10 to 12, the security paper is provided with a foil element, such as an embedded security thread or a foil strip that is covered on one side.

FIG. 10 shows, by way of example, a security paper 100 in which a foil strip 102 is embedded. Here, FIG. 10(a) depicts a top view of the security paper, and FIGS. 10(b) and 10(c) show cross sections through the security paper in FIG. 10(a) along the lines B-B and C-C. Prior to its embedment in the security paper, the foil strip 102 was contiguously coated on the bottom 104 with heat seal coating 107. On the other side 106, in contrast, only tracks 108 at the foil edge were provided with heat seal coating such that the middle foil region of the top 106 remains uncoated.

At paper manufacture, a nonwoven material now forms on both sides of the foil. In addition, for example with the aid of electrotypes, on the bottom 104 of the foil strip is left uncovered a window 110 in which the foil element becomes visible. On the bottom 104 that is contiguously coated with heat seal coating 107, the nonwoven material is set, except for the uncovered window 110, in the drying section. On the opposing front 106, in contrast, only the edge regions 108 prepared with heat seal coating are set in the drying section.

Subsequently, with a laser, a shape 112 is cut out above the uncovered window 110 of the opposite side 104, as is best perceived in the cross-sectional diagram in FIG. 10(c).

Here, the laser parameters are chosen such that only the paper is cut, but not the foil strip 110. This can be achieved in that, for example, the laser cutting is carried out with a laser wavelength for which the foil strip 102 is transparent and non-absorbent.

The cut-out shape 112 can then be removed with a suction apparatus since, due to the lack of heat seal coating on the front 106 and the non-stick foil surface, no connection has been created between the cut-out piece of paper and the foil.

Another exemplary embodiment having a foil element will now be explained with reference to FIGS. 11 and 12. First, FIG. 11(a) depicts a top view of a security paper 120, and FIGS. 11(b) and 11(c) show cross sections through the security paper in FIG. 11(a) along the lines B-B and C-C. In the security paper 120 is embedded a security thread 122 that is perceptible primarily in the window regions 124 that are produced in the back of the paper with papermaking technology, as shown in FIG. 11(b).

Further, in the region of the window 124 in the front of the security paper 120, a sharply edged opening 126 that extends beyond the security thread 122 is introduced into the paper substrate with a laser. For this, the laser parameters are chosen such that, although the paper substrate 120 is cut by the laser, the security thread 122 is not. In the region of the opening 126, the security thread 122 is then perceptible from both sides, as shown in FIG. 11(c).

In the alternative design shown in FIG. 12, in contrast to the embodiment in FIG. 11, the laser-cut opening 128 is not made over the security thread 122, but rather the security thread is framed by the opening 128. With the exception of this difference, the views in FIGS. 12(a) to (c) correspond to those in FIGS. 11(a) to (c).

Unlike in FIG. 11, in the exemplary embodiment in FIG. 12, the surface of the security thread 122 is perceptible only in the window regions 124. Such an embodiment may be used especially when the laser radiation could damage or have an undesired effect on the foil material of the security thread 122. Since the security thread normally oscillates, in this design, the opening 128 can typically not be perfectly centered on the security thread 122, as indicated by the register variations shown in FIGS. 12(a) and (c).

FIG. 13 shows a design in which a sharply edged opening 132 is produced in the region of a thin site 134 of the security paper 130 with a laser. The thin site 134 can be produced, for example, by a drawn-off pressure-former ply (a paper ply produced by jetting the pulp onto a cylinder mold) or with the aid of electrotypes. Since the paper thickness is reduced in the region of the thin site 134, it is possible to work with lower laser power when laser cutting. In this way, higher cutting speeds are achieved, such that more complex shapes can be realized. This modification can be combined with all embodiments in which a sharply edged opening is inscribed in a paper substrate with a laser.

Further exemplary embodiments of the present invention will now be explained with reference to FIGS. 14 and 15. In the exemplary embodiment in FIG. 14, a thin site 142 of predefined shape is first produced in the paper substrate 140 with the aid of a laser. Here, the paper material is vaporized, burned or otherwise ablated. Just so much material is ablated that a small residual thickness 144 of the substrate remains, as shown in FIG. 14(a). At some locations, depending on the thickness tolerance of the substrate, it is also possible to ablate so much that no material at all is present any longer. Since the thin site is produced by laser cutting, the edge surface 146 is sharply delimited and smooth.

The piece of paper 144 remaining after the laser treatment is then removed by blowing or suctioning it out. Since it is only a very thin paper ply, the piece of paper 144 tears out at the edges and, in this way, produces an irregular subregion 148 in the edge surface of the now through opening 145, as depicted in the cross-sectional diagram in FIG. 14(b) and the top view in FIG. 14(c). If the edge surface of the opening 145 is followed along a direction extending through the paper thickness, beginning at the surface 141 of the paper substrate, then the sharply delimited subregion 146 and the characteristically irregularly shaped subregion 148 follow one another in succession. When the security paper is viewed, the through opening 145 appears with different impressions from opposing sides of the security paper, depending on whether the sharply delimited edge region 146 or the irregular edge region 148 adjoins the paper surface.

As an exemplary combination of laser-produced openings with thin sites in the paper substrate (FIG. 13), the exemplary embodiment in FIG. 15 first shows a thin site 151 produced in the security paper 150 with papermaking technology, such as a watermark. As described in connection with FIG. 14, in the region of this thin site 151 is then produced with the laser a second sharply edged thin site 152 that leaves only a small residual thickness 154 of the paper substrate remaining, as shown in FIG. 15(a).

This remaining piece of paper 154 is torn out by blowing or suctioning such that, at the bottom of the paper substrate 150, an irregular edge surface 158 is produced, as depicted in FIG. 15(b). The edge region 156 produced by laser cutting, in contrast, is sharply delimited. The through opening 160 created is embedded in a watermark region 151 that, when looked through, appears clearly, see FIG. 15(c). It is understood that the design of the opening 160 and of the watermark region 151 can likewise be associated in meaning.

Overall, along a direction extending through the paper thickness, the edge surface of the opening 160 exhibits, in succession, a sharply delimited subregion 156 and a characteristically irregularly shaped subregion 158. Here, too, when viewed from opposing sides of the security paper, the through opening 160 appears having different impressions, depending on whether the sharply delimited edge region 156 or the irregular edge region 158 adjoins the paper surface.

In the embodiments described, the sharply edged opening can also be produced by a punching tool rather than with a laser. It is also not necessary that the edge surfaces of the laser-cut openings run parallel and vertical to the paper surface, as shown in the figures for the sake of simpler illustration. Rather, it can be advantageous to set the laser source and/or the paper at an angle when cutting, so that “tapered” edges are produced.

For this, FIG. 16 shows, in (a) and (b), two exemplary embodiments in which sharply edged, laser-cut openings 172 and 174 are introduced into paper substrates 170. The tilt of the edge surfaces 178 of the openings can be set as desired by choosing a suitable beam divergence and beam tilt. The openings 172 and 174 are each covered with a foil 176. As immediately apparent, the tapered edges lead to a softer transition between the foil 176 and the paper substrate 170. Through such edge shapes, the susceptibility of the openings to dirt is significantly reduced.

Furthermore, the design in FIG. 16(b), in which the edge surfaces have different tilts, has proven to be particularly advantageous in a duplex lamination of the openings with foils (not shown). Problems with the potential entrapment of air between the opposing foils can be minimized through such an edge design.

As a further advantage, the openings in FIG. 16 also exhibit an additional optical effect, as they appear to be of different sizes depending on the viewing direction.