CN101892612A

CN101892612A - Safety paper and manufacture method thereof

Info

Publication number: CN101892612A
Application number: CN2010101901473A
Authority: CN
Inventors: 于尔根·拉克; 曼弗雷德·海姆; 安德烈亚斯·普雷奇
Original assignee: Giesecke and Devrient GmbH
Current assignee: Giesecke and Devrient GmbH
Priority date: 2005-05-12
Filing date: 2006-05-03
Publication date: 2010-11-24
Also published as: US20080216976A1; CN101171145A; EP2143565B1; DE102005022018A1; WO2006119896A2; RU2408466C2; CN101171145B; BRPI0612347A2; RU2007144576A; EP2143565A1; ATE520543T1; ES2368498T3; WO2006119896A3; EP1904311B1; EP1904311A2

Abstract

The present invention relates to be used to make for example safety paper of banknote, identity card etc. of secure file or valuable file, it has at least two through holes (12,16), it is characterized in that, first through hole (12) in the described through hole forms in paper-making process and has irregular feature at its fringe region (14), second through hole (16) in the described through hole finishes the back in papermaking and forms by cutting or punching press, and has the fringe region (18) that sharply defines.

Description

Security paper and method for the production thereof

The present application is a divisional application of the invention patent with application number 200680015800.4, named as "safety paper and its manufacturing method", applied to the intellectual property office of China on 2006, 5/3/2006.

Technical Field

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

Background

For protection purposes, security papers or valuable documents are often provided with various authentication features to allow the identity of the security paper or valuable document to be authenticated to be confirmed and at the same time to prevent unauthorized copying.

Within the scope of the present invention, the term "security paper" is generally a non-printed paper in quasi-endless (quasi-end) form and which is subsequently further processed. The term "valuable document" refers to a document that is finished for a particular use. In the present invention, valuable documents refer in particular to banknotes, stocks, bonds, certificates, vouchers, checks, valuable tickets, other papers that can be counterfeited (such as passports and other identification documents) and product protection elements (such as labels, seals, packaging, etc.). In the following, the simplified description "security paper" or "valuable document" includes all the above mentioned documents and product protection means.

Such a valuable document is described in patent application publication WO 95/10420, in which, after the production of the valuable document, a through-hole is punched out, which is subsequently closed on one side by a cover foil which is superimposed around the through-hole. The cover foil is transparent at least in sub-areas, so that when an important document is to be copied, the background is displayed and copied down accordingly by the copying machine. In this way, counterfeits can be easily identified. However, holes formed by stamping may also be manufactured by counterfeiters. Although the colour copy of the real document of value no longer has transparent areas and is similar to the real document of value, the areas can be punched out after copying and then closed with a suitable cover foil. Such artefacts are difficult to recognise.

In order to remedy the above-mentioned deficiencies, in the patent application publication WO 03/054297, it has been recommended to produce through-holes at the time of sheet production. Such holes produced during the formation of the paper have, in their edge regions, irregular features which can no longer be formed after the manufacture of the paper. The irregular character is manifested by the lack of sharp cutting edges, or by the irregular increase in fibers at the edge regions and the introduction of individual fibers into the apertures. The openings thus produced have a security level as high as that of the watermark formed during the paper manufacturing process, or of the security thread embedded in the paper during the paper manufacturing process.

However, such openings produced in the papermaking process are often of different quality and difficult to reproduce. There is also a risk that the fibre bundle partially closes the opening to some extent.

Disclosure of Invention

For the above reasons, it is an object of the present invention to provide a security paper which overcomes the disadvantages set forth in the background. In particular, the security paper is used to combine high security apertures formed during the paper manufacturing process with good perceptibility of the identification features formed by the apertures.

The above objects are achieved by the features of the independent claims, the dependent claims being further developments of the invention.

According to a first aspect of the invention, a security paper has at least two through-holes, a first of which is formed during the paper production and has irregular features in its edge regions, and a second of which is formed by cutting or punching after the paper production has ended and has sharply defined edge regions.

Here, the outline shapes of the first and second through holes are related in meaning. In particular, the contour shape of the first and second through holes constitutes relevant or supplementary information, such as an image figure, a letter or a code.

In a preferred embodiment, the second sharply defined through hole is produced by laser cutting. Here, the second sharply defined edge surface of the second through hole is parallel or perpendicular to the paper surface. Conversely, in other embodiments, the second aperture is formed with an edge region that is inclined relative to the surface normal. This can be achieved by appropriate selection of the offset or inclination of the laser beam relative to the surface of the paper. In particular, the laser beam is offset or inclined with respect to the paper surface, so that the second apertures have edge surfaces which are differently inclined with respect to the surface normal. The tapered edge makes the cover foil arranged above the opening softer to the paper substrate, enabling a lower susceptibility to soiling.

Furthermore, the differently inclined edge surfaces provide a multi-layer structure of apertures and foils and in particular minimize the problem of air being present in the multi-layer structure. Furthermore, apertures with inclined surfaces have an additional optical effect (with respect to the vertical edge surfaces) since they exhibit different sizes depending on the viewing direction.

According to an advantageous development of the invention, the security paper has a predetermined thickness and has a thin location with a reduced paper thickness, at least the second through-hole being introduced into the area of the thin location. The thin locations comprise, inter alia, watermarks.

The two openings are closed with foil elements on one side of the security paper. In some designs, the two openings are closed with foil elements on both sides of the security paper. Here, potential problems of air capture are minimized by the above-mentioned beveled edges.

According to another aspect of the invention, a security paper is provided comprising an edge surface of the through-hole comprising a first sharply defined sub-area and a second sub-area having irregular features. The first and second subregions alternate along a contour of the via. In particular, the first and second subregions alternate in an irregular sequence along the contour of the via.

In one embodiment, each of the first and second sub-regions extends through the thickness of the entire sheet. It is also possible to make said first and second sub-areas follow each other continuously in the direction along the thickness of the paper and complement each other to form said through-holes. For example, in one edge portion, the sharply defined sub-region may extend through 90% of the paper thickness while the edge surface of the remaining 10% of the paper thickness is irregular. Such edge portions may also be combined with other edge portions in which the first or second sub-area extends completely through the entire thickness of the paper.

Such a sequence of first and second sub-areas along the thickness of the security paper can be produced, for example, because during the paper production process through-holes with irregular features are formed in the edge areas, the edge areas of the through-holes are modified by means of laser or punching techniques after the paper production has ended and in this way the edge areas are sharply defined in the sub-areas. This modification is preferably produced by means of laser cutting techniques, the above-mentioned possibility of the edge surfaces being inclined also being present here.

Such a sequence of first and second sub-areas along the thickness of the security paper can be produced, for example because in the security paper a paper segment with an opening of the desired shape (with interrupted sharply defined cutting lines) can be defined; the paper section can thus be torn off the security paper, in particular blown out or pulled out. Preferably, the paper segment is defined by laser cutting, the possibility of the above-mentioned edge surface being inclined also being present.

Another possibility for generating the above-described sequence of first and second subregions consists in: a sharply defined thin region with an opening of the desired shape is produced in the security paper, and the paper section formed in the thin position can be torn off the security paper, in particular blown out or pulled out. Furthermore, in a preferred method, the sharply defined thin regions are formed by laser cutting, if necessary, with the above-mentioned inclined edge surfaces.

In an advantageous embodiment the security paper has a predetermined paper thickness and a thin location of reduced paper thickness, the second through hole being introduced into the thin location area (e.g. the watermark) and the through hole being introduced into the thin location area.

The through-hole is closed with a foil element at one or both sides of the security paper.

According to another aspect of the invention, a security paper comprises a paper having at least two through holes which are formed during the paper manufacturing process and have irregular features in their edge regions, wherein the through holes are combined with engravings formed by laser etching, which engravings complement the through holes to form protruding features. Preferably, the through-hole is closed with a foil element at one or both sides of the security paper.

According to another aspect of the invention, the security paper comprises embedded foil elements which are visible through a sub-area of the window area formed with the paper making technique. The security paper also has, in the region of the foil elements, openings which are formed by cutting or punching techniques after the end of the paper manufacture, the openings having sharply defined edge regions.

In an advantageous embodiment, the sharply defined opening is provided above the foil element and/or in the immediate vicinity of the foil element. Preferably, the sharply defined apertures are continuous except for areas of potential overlap with the foil elements.

According to a preferred embodiment, the window area is provided at a first main surface of the security paper, the sharply defined apertures extending from the opposite main surface of the security paper to the foil elements.

In all embodiments, the foil element constitutes a security element, in particular a security thread or a security strip.

Advantageously, the sharply defined apertures are formed by laser cutting. Here, the edge surface of the opening may be inclined, as described above. In an advantageous embodiment, the security paper has a predetermined paper thickness and a thin location of reduced paper thickness, the sharply defined apertures being introduced into the area of the thin location. Advantageously, the sharply defined opening is closed with a thin element on one or both sides of the security paper.

The invention also includes valuable documents, such as banknotes, identification cards, etc., having the above-mentioned security paper. The security or valuable document of the invention can be used to prevent various counterfeiting of articles.

Drawings

Further exemplary embodiments and advantages of the invention will be described below with reference to the drawings, wherein scales and proportions are omitted in the drawings for the sake of clarity. Wherein,

fig. 1 is a schematic view of a banknote made of security paper according to an exemplary embodiment of the present invention;

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

FIGS. 3 and 4 are exemplary embodiments of two inventive designs of the present invention wherein two are deliberately related in security paper;

fig. 5-7(a) are intermediate steps in the manufacture of security paper according to another exemplary embodiment of the present invention, and fig. 5-7(b) are top views thereof;

fig. 8(a) is an intermediate step of manufacturing a security paper according to another exemplary embodiment of the present invention, and fig. 8(b) is a sectional view of fig. 8(a) with a cut shape removed;

FIG. 9 is a top view of a security paper according to another exemplary embodiment of the present invention;

fig. 10(a) is a top view of a security paper with embedded foil elements according to an exemplary embodiment of the present invention; FIGS. 10(B) and (C) are sectional views taken along lines B-B and C-C in FIG. 10 (a);

fig. 11(a) and 12(a) are top views of a security paper with foil elements according to another exemplary embodiment of the present invention, fig. 11(B) and 12(B) and fig. 11(C) and 12(C) being cross-sectional views taken along lines B-B and C-C in fig. 11(a) and 12(a), respectively;

FIG. 13 is a design in which a thin land area is created with laser cut openings using papermaking techniques;

fig. 14(a) and (b) are cross-sectional views in two steps of manufacturing a security paper according to another exemplary embodiment of the present invention; fig. 14(c) is a top view of the security paper in step 14 (b);

FIGS. 15(a) - (c) show laser-formed cut openings in thin areas created by papermaking techniques, as in FIG. 14; and

fig. 16(a) and (b) show two exemplary embodiments for laser cutting apertures having edge surfaces that are inclined relative to the surface normal.

Detailed Description

The present invention will be described in detail below using banknotes as an example. To this end, fig. 1 is a schematic illustration of a banknote 10 having two through

holes

12 and 16. In which a through-hole 12 is formed during the manufacture of the security paper for the banknote 10 and has an irregular edge region 14 of fibres. The edge 14 is a feature of an aperture that has been made in the sheet formation and cannot later be formed by stamping or cutting the sheet.

The second through hole 16 is formed by laser cutting or with a punching tool after the paper is manufactured and has a sharp border area 18. The two through-

openings

12 and 16 have double the same information spatially separated from one another, in each case an isosceles triangle in the exemplary embodiment shown in fig. 1. It will be appreciated that instead of triangles also other more complex shapes whose outlines constitute, for example, strings of numbers or simple figures may be used.

Even if the information represented by the first opening 12 is not immediately perceptible due to its irregular edge zone 14, the viewer can establish a relationship between the two shapes and perceive the information unambiguously due to the clear outline formed by the second opening 16. Due to the doubled information with different decorations (attere), the attention of the viewer is specifically drawn to the difference in the two apertures. The high security characteristics of the irregular edge openings 12 are thus combined with the clear perceptibility of openings 16 with sharp edges.

Fig. 2 shows a top view of a security paper 20 according to an exemplary embodiment of the present invention. The security paper 20 has a first aperture 22 and a second aperture 26, the first aperture 22 being produced using a paper-making technique and having an irregular edge region 24. The second opening 26 is created using a laser cutting technique and has a sharp edge 28. Here, the contour shapes of the two openings 22 and 26 are related in meaning. However, unlike the exemplary embodiment in fig. 1, they do not have the same information, but rather form a complementary part of the information binding segment.

Preferably, the pattern shown matches the different edge characteristics of the two apertures. For purposes of description, FIG. 2 shows a floral pattern wherein flowers are first formed by the irregular edge openings 22, followed by stems and leaves formed by the second sharp edge openings 26. Since flowers have very different and variable shapes in nature, the overall illustrated shape looks very realistic. Meanwhile, due to the shape of the two openings, the generation of counterfeit products is prevented.

Fig. 3 and 4 show another exemplary embodiment of the invention in which the profile shapes of the first aperture with irregular edges and the second aperture with sharp edges are related in meaning.

The exemplary embodiment in fig. 3(a) shows a sun in the shape of a ring with irregular first openings 32 having rays directed radially outward and formed by laser cutting or punching triangular openings 34. In the exemplary embodiment, the radiation formed through the second apertures 34 forms a pattern that depends on the first apertures. Further, in fig. 3(b), the star-shaped first openings 36 with irregular edges form a main pattern, wherein the ring-shaped second openings 38 with sharp edges are not independent in pattern.

Fig. 4 shows a further embodiment of the invention, in which in each case the irregular-edged openings 42 and the sharp-edged openings 44 complement one another to form the denomination "100" of the banknote 40. Often, the denomination of the banknote is again clearly applied (e.g. imprinted) at another location. In an actual banknote it is possible to use only one or two of the designs of figure 4, and if applicable, other designs may also be provided at various locations of the banknote.

The two apertures deliberately associated may also be such that the aperture with irregular edges is modified by an aperture with sharp edges, as described below with reference to figures 5 to 7. Fig. 5(a) shows a top view of a security paper 50, initially incorporating sharp-edged apertures 50 at the paper manufacturing stage. After the paper is manufactured, the opening 52 is modified by laser cutting to have two sharp-edged openings 54, the positions of the openings 54 being drawn with a broken line in fig. 5 (a).

After laser cutting, the single continuous through hole 56, due to the two-stage manufacturing described above, has, on the one hand, a sub-region 58 comprising irregular edges (as shown in fig. 5 (b)), and, on the other hand, a sub-region 59 comprising sharp edges. With the above modifications, the edge characteristics of the two openings can be combined into a single via.

In the exemplary embodiment shown in fig. 6, in a first manufacturing stage of the paper, openings 62 with irregular edges (having a predetermined pattern shape, for example, four arrow shapes, as shown in fig. 6 (a)) are introduced into the security paper 60. The irregular edge regions 64 in the pattern are re-cut with the laser. In this way, as shown in fig. 6(b), the through-hole 66 has, on the one hand, a subregion 68 comprising irregular edges and, on the other hand, a subregion 69 comprising sharp edges. Here, the relationship and order of the

sub-regions

68 and 69 can be freely selected.

Fig. 7 shows such an exemplary embodiment, and as with the embodiment of fig. 6, the edge irregularity apertures 72 are first introduced into the security paper 70, as shown in fig. 7 (a). After the paper is manufactured, the openings 72 are completely re-cut (reference numeral 74) with the laser, and the size of the re-cut portions 74 is selected to be somewhat smaller than the size of the openings 72. In this way, the through-hole 76 is established to have the

sub-regions

78 and 79 in an irregular order, the sub-regions 78 having irregular edges and the sub-regions 79 having sharp edges, as shown in fig. 7 (b).

Regular and irregular edge region sequences can be obtained without the involvement of openings already produced during the papermaking process. The desired shape of the through-hole 82 can be cut in the security paper 80, for example by means of a laser, in such a way that the cutting line 84 does not form a continuous cutting curve, but is interrupted by non-cut sub-portions 86, as shown in fig. 8 (a). The subparts 86 form retaining bands to initially prevent the cut shapes from being removed.

The cut shapes can then be blown out with a jet of air or sucked out by vacuum. In this way, the cut portion of the paper is irregularly torn at the retention strip 86, while the cut line 84 forms a sharp boundary edge, as shown in part 85 of fig. 8 (b). The edge region of the opening 82 thus has a sequence of irregular subregions 88 and sharp cutting subregions 89, the relative size and sequence of which can be freely selected by means of the cutting control during laser cutting.

In another exemplary embodiment of the invention shown in fig. 9, the security paper 90 has through holes 92 formed during the paper manufacturing process and having irregular fiber edges. The through-holes 92 are combined with scribe lines 94 formed by laser etching. The engraved lines 94 are formed by locally thinned regions in the security paper 90, as described in publication WO 98/03348, the disclosure of which is incorporated herein. According to the invention, the position and arrangement of the engraved lines 94 is chosen such that they form a protruding shape, complementing the openings 92.

The engraved lines 94 are virtually imperceptible when viewed in reflected light, and the area of the opening 92 determines its shape. In contrast, if the security paper is viewed with transmitted light, the engraved lines 94 stand out clearly due to the smaller sheet thickness and supplement the openings 92 to form a three-dimensional protruding shape. In this way, the combination of irregular openings 92 and engraved lines 94 will have an optically significant effect between 2D and 3D.

According to another exemplary embodiment of the present invention, which is illustrated with reference to fig. 10-12, the security paper is provided with foil elements, such as an embedded security thread or foil strip, which is covered on one side.

Fig. 10 shows by way of example a security paper 100 with an embedded foil strip 102. Here, fig. 10(a) is a top view of the security paper, and fig. 10(B) and (C) show sectional views taken along lines B-B and C-C in fig. 10 (a). In embedding the foil strip 102 in the security paper, the foil strip 102 is continuously coated on the bottom 104 with a heat seal coating 107. On the other side 106, instead, only the tracks 108 at the edges of the foil are provided with a heat seal coating, so that the middle foil area of the top portion 106 is uncoated.

In paper manufacture, the non-woven material is formed on both sides of the foil. Furthermore, the foil strip is uncoated at its bottom 104, for example by means of an electrotype, and has a window 110, from which window 110 the foil elements can be seen. On the bottom 104, which is continuously coated with the heat seal coating 107, except for the uncovered window 110, a nonwoven material is provided on the dried portion. On the opposite front side 106, in contrast, a heat seal coated edge area 108 is provided at the drying section.

Subsequently, using a laser, a shape 112 is cut over the uncovered window 110 on the opposite side 104, as can be best seen in the cross-sectional view in fig. 10 (c). Here, the laser parameters may be selected such that only the sheets are cut and not the foil strip 110. This can be done because, for example, laser cutting can be performed with a laser wavelength that is transparent and non-absorbing to the foil strip 102.

The cut shape 112 can then be removed with suction, since no connection is created between the cut sheet section and the foil due to the front side 106 and the non-foil-adhering surface.

Exemplary embodiments having foil elements are described below with reference to fig. 11 and 12. First, fig. 11(a) shows a top view of the security paper 120, and fig. 11(B) and (C) are sectional views taken along lines B-B and C-C through the security paper in fig. 11 (a). Embedded in the security paper 120 is a security thread 122 which is perceptible in a window area 124, the area 124 being produced on the back of the paper using paper making techniques, as shown in figure 11 (b).

In addition, in the region of the window 124 on the front side of the sheet 120, a sharp-edged aperture 126 extending beyond the security thread 122 is introduced into the sheet substrate using a laser. For this purpose, the laser parameters are selected such that the laser cuts only the paper substrate 120 and not the security thread. In the area of the aperture 126, the security thread 122 is visible from both sides, as shown in fig. 11 (c).

In contrast to the embodiment shown in fig. 11, in the alternative design shown in fig. 12, the laser cut opening 128 is not formed in the security thread 122, but the security thread is framed. Except for this difference, fig. 12(a) - (c) correspond to fig. 11(a) - (c).

Unlike fig. 11, in the exemplary embodiment in fig. 12, the surface of the security thread 122 is only perceptible in the window area 124. This embodiment is particularly useful when the laser radiation is back-damaged or has an adverse effect on the foil material of the security thread 122. Since the security thread is typically oscillated, in this design the aperture 128 is typically not perfectly centered on the security thread, as shown by the registration variation shown in fig. 12(a) and 12 (c).

Fig. 13 shows a design in which a laser is used to create sharp-edged openings 132 in the region of thin spots 134 of security paper 130. The thin spot 134 is formed, for example, by extracting a pressure-forming layer (a paper layer formed by injecting pulp into a cylinder mold) or by using an electrotype. Since the paper thickness is reduced in the region of the thin location 134, a low laser power can be utilized in the laser cutting. In this way, high cutting speeds can be achieved, thereby achieving more complex shapes. This variation can be combined with all embodiments where a laser is used to form sharp-edged openings in a paper substrate.

Another exemplary embodiment of the present invention will be described below with reference to fig. 14 and 15. In the embodiment in fig. 14, thin sites 142 of a predetermined shape are first formed on a paper substrate 140 using a laser. Here, the paper material is evaporated, burned or melted. Most of the material is melted, leaving only a small thickness 144 on the substrate, as shown in fig. 14 (a). At some point, all of the material may be melted, depending on the thickness tolerance of the substrate. Since the thin locations are created by laser cutting, the edge surfaces 146 are sharply defined and smooth.

The paper segment 144 left after the laser treatment is removed by a blowing or suction operation. Since the paper layer is very thin, the paper segment 144 is torn at its edges and in this way irregular sub-areas 148 are created on the edge surfaces of the through-holes 145, as shown in the cross-sectional view in fig. 14(b) or the top view in fig. 14 (c).

The edge surfaces of the apertures 145 extend in a direction through the thickness of the paper, starting from the surface 141 of the paper substrate, successively through sharply defined sub-areas 146 up to sub-areas 148 having a characteristic irregular shape. When viewing the security paper, the through-hole 145 appears differently shaped on the opposite side of the security paper, depending on whether the sharply defined edge region 146 or the irregular edge region 148 is adjacent to the paper surface.

As an exemplary combination of laser-produced apertures and thin locations in the paper substrate (fig. 13), the exemplary embodiment in fig. 15 first shows thin regions 151 in the security paper 150 created with paper-making techniques (e.g., watermarks). As described with reference to fig. 14, in the region of the thin location 151, a second sharp-edged thin location 152 is created with a laser, which leaves only a small residual thickness 154 of the paper substrate, as shown in fig. 15 (a).

The remaining paper segment 154 is torn by a blowing or suction operation, resulting in an irregular edge surface 158 at the bottom of the paper substrate 150, as shown in fig. 15 (b). In contrast, the edge region 156 produced by laser cutting is sharply defined. The resulting through-hole 160 is embedded in the watermark region 151, the through-hole 160 being clearly visible when viewed therethrough, as shown in fig. 15 (c). It should be understood that the design of the through-hole 160 and the watermark region 151 may also be deliberately related.

The edge surfaces of the opening 160, the sharply defined sub-regions 156 and the characteristic irregularly shaped sub-regions 158 are shown in succession in the direction extending through the thickness of the paper. Here, the through-hole 160 appears in a different shape when viewed from the opposite side of the security paper, depending on whether the sharply defined edge region 156 or the irregular edge region 158 abuts the paper surface.

In the described embodiments, sharp-edged apertures can also be produced by a punching tool instead of a laser. The edge surfaces of the laser cut openings do not necessarily have to be parallel or perpendicular to the paper surface, as shown in simplified form in the figures. Instead, when cutting, the laser source and/or the paper may advantageously be set at an angle, thereby creating a "tapered" edge.

To this end, two exemplary embodiments are shown in fig. 16(a) and 16(b) in which sharp-edged, laser-

cut apertures

172 and 174 are introduced into the paper substrate 170. The inclination of the edge surface 178 of the aperture can be set as desired by appropriately deflecting and tilting the laser beam. As can be seen from the appearance, the tapered edges result in a softer transition between the foil 176 and the paper substrate 170. By this edge shape, the soiling susceptibility of the opening is greatly reduced.

Furthermore, the design in fig. 16(a) with different inclinations of the edge surfaces has proved to be very advantageous in a two-layer open cell structure with foil (not shown). The problem of potential air between the opposing foils can be minimized by this edge design.

As a further advantageous effect, the apertures in fig. 16 also have an additional optical effect, since they appear to be of different sizes when viewed in different directions.

Claims

1. A security paper for the production of security or valuable documents, having an embedded foil element which is visible through a sub-region of a window region formed by means of a paper-making technique, wherein the security paper has, in the region of the foil element, an opening which is formed by means of a cutting or punching technique after the end of the paper production, which opening has a sharply defined edge region and is arranged directly adjacent to the window region produced by means of the paper-making technique.

2. The security paper of claim 1, wherein the sharply defined openings are provided above and/or in close proximity to the foil elements.

3. The security paper of claim 1, wherein the sharply defined apertures are continuous except in areas of potential overlap with the foil elements.

4. The security paper as claimed in claim 1, wherein the window area is provided at a first major surface of the security paper, the sharply defined apertures extending from an opposite major surface of the security paper to the foil element.

5. The security paper as claimed in claim 1, wherein the foil element constitutes a security element, in particular a security thread or a security strip.

6. The security paper as claimed in claim 1, wherein the sharply defined openings are formed by laser cutting.

7. The security paper as claimed in claim 1, wherein the security paper has a predetermined paper thickness and a thin location of reduced paper thickness, the sharply defined apertures being introduced into the region of the thin location.

8. The security paper as claimed in claim 7 wherein the thin location comprises a watermark.

9. The security paper of claim 1, wherein the sharply defined aperture is formed with an edge surface that is inclined relative to a surface normal.

10. The security paper of claim 9, wherein the sharply defined apertures have edge surfaces that vary in inclination with respect to the surface normal.

11. The security paper as claimed in claim 1, wherein the sharply defined opening is closed with a thin element on one or both sides of the security paper.

12. A method for manufacturing a security paper having an embedded foil element according to at least one of claims 1 to 11, wherein,

-embedding foil elements in the security paper during the paper manufacturing process;

-generating a window area in which the foil element is made visible; and

-forming an edge area with a sharp definition by means of a cutting or punching technique in the area of the foil element above or in the immediate vicinity of the window area after the end of the paper manufacturing.

13. The method of claim 12, wherein the sharply defined openings are created by laser cutting.

14. The method of claim 12, wherein a sharply defined through-hole is formed directly adjacent to the foil element.

15. The method of claim 13, wherein the sharply defined openings overlap the foil regions, the laser parameters being set such that the laser cuts only the paper substrate and does not cut the foil elements.

16. A method according to claim 12, wherein, at a first major surface, the foil elements are continuously coated with the heat seal coating before being embedded, and at a second, opposite major surface, the heat seal coating is prepared only at the edges of the foil, such that a central area of the foil elements is uncoated.

17. The method of claim 16, wherein the window area is created in the continuously coated major surface.

18. The method of claim 16, wherein the sharply defined openings are created only in a middle region of the edge-coated major surface.

19. The method of claim 16, wherein the sharply defined openings are formed by laser cutting.

20. The method of claim 19, wherein the laser beam is offset or tilted relative to the security paper such that the sharply defined aperture is formed with an edge surface that is tilted relative to a surface normal.

21. The method of claim 19, wherein the laser beam is offset or tilted with respect to the security paper such that the sharply defined aperture is formed with edge surfaces that are differently tilted with respect to a surface normal.

22. The method according to claim 12, wherein the through-hole is closed with foil elements at one or both sides of the security paper.

23. Use of a security paper according to at least one of claims 1 to 11 for ensuring that various items are counterfeited.

24. A security document or valuable document such as a banknote, an identification card or the like, provided with a security paper according to at least one of claims 1 to 11.