Security element

The invention relates to a security paper, a security document or a value document made of such security paper, a method for producing security paper and a screen for producing said security paper. The paper according to the invention comprises a security element, namely a barcode in the form of a watermark.

It is known to insert a bar code into paper in the form of a watermark, which is in particular inserted into the security paper from which the documents to be secured or the documents of value are made. For example, using a barcode, the authenticity of banknotes can be checked if all banknotes with a given value and date of issue have a certain watermark made in the same way. By comparing with the serial number and the denomination which are printed on the banknote, it is possible to check the authenticity of the banknote using the barcode. Depending on the complexity of the information contained in the watermark barcode, the barcode may become relatively long, which is undesirable for small size valuable documents such as banknotes for example.

The problem, however, is not only with the length of the bar code, but more particularly with its verifiability to determine the authenticity of the document. The reason is that the wider the stripes are incorporated into the paper in the form of watermarks, the more irregular they appear in the light passing through them. This is because it is very difficult to make a watermark having regular dark surfaces. In producing the watermark, a papermaking screen is used so that the deposition of the paper fibers of the sheet formation is disturbed. If the papermaking wire is deeply embossed, more furnish is deposited in this area, while deep embossing inhibits the deposition of the furnish. In the case of an embossed surface above all edges, they are correctly represented. The surface itself becomes lighter or darker towards its inner region.

The object of the present invention is to provide a bar code in the form of a watermark which is more universal and has a smaller surface area compared to the solutions known in the state of the art. A further object of the invention is to provide a security paper having such a barcode and a security document or value document made therefrom, as well as a method for its production and a papermaking wire for the production of security paper.

These objectives have been achieved by the solutions of the invention - security paper, a security document or a value document made of such paper, a security paper manufacturing method and a screen for producing said security paper.

The subject of the invention is a security paper with a general density of F0 fibers intended for the production of valuable documents or documents that require security such as banknotes, checks, shares, identification cards, tickets for public transport, admission tickets and the like, having a bar code consisting of information separated by separating fields characterized by the fact that that the separation fields are incorporated into the paper in the form of watermarks so that the fiber density of the security paper in the area of ​​the separation fields differs from the overall fiber density.

Preferably, the fiber density of the security paper in the regions of the information-carrying stripes differs in a positive or negative direction from the overall fiber density F0 compared to the regions of the separation fields.

Preferably, the fiber density of the security paper in the areas of the information-carrying stripes is higher and in the areas of the separating fields it is lower than the overall fiber density F0.

Preferably, the fiber density of the security paper in the areas of the information-carrying stripes corresponds to the overall fiber density.

Preferably, the separation fields are narrower than the information stripes.

Preferably, when viewing the security paper with light passing through it, at least one of the separation fields appears lighter than the area of ​​the security paper with general fiber density, and at least one of the separation fields appears darker than the area of ​​the security paper with general fiber density F0.

PL 218 532 B1

Preferably, the information conveying strip at the edge of the bar code has specific characteristics that enable it to be determined which information is assigned to each of the strips of differing widths comprising the bar code.

Preferably, the characteristic property is the width and / or the fiber density of the strip at the edge.

Preferably, the barcode is in the form of a two-dimensional barcode.

Preferably, the security paper has an additional medium capable of storing information, such as, for example, a magnetic area capable of storing information or a microchip.

The invention also relates to a security document or a value document characterized in that it is made of the security paper according to the invention.

Preferably, the document requiring security or the value document is selected from the following group of documents: banknote, check, share, identification card, ticket to public transport, admission ticket.

Preferably, the document has an additional medium capable of storing information, such as, for example, a magnetic area capable of storing information or a microchip.

The invention also relates to a method of producing security paper with a general density of F0 fibers intended for the production of valuable documents or documents that require security, such as banknotes, checks, shares, identification cards, tickets for public transport, admission tickets and the like, having a bar code consisting of from stripes carrying information separated by dividing fields, characterized by that the security paper is made in the form of a watermark in the areas of the separation fields with a fiber density different from the overall fiber density.

Advantageously, the method comprises the use of a papermaking screen which is shaped in a particular manner in the regions of the separation fields, whereby, in these regions, the deposition of fibers for forming a watermark is increased or reduced in the security paper produced.

Preferably, the papermaking screen is shaped in the regions of the information-carrying stripes such that fiber deposition is neither reduced nor increased in these regions.

In another preferred embodiment, the papermaking wire is embossed in the regions of the information-carrying strips such that fiber deposition is reduced or enhanced in these regions.

Preferably, the papermaking wire is embossed in at least one of the separating fields in such a way that the deposition of the fibers is enhanced.

In another preferred variant, the papermaking wire is electroplated in the region of at least one of the separating fields, whereby fiber deposition is reduced.

The invention also relates to a papermaking screen for the production of security paper having a barcode consisting of information-carrying strips separated by separation fields, characterized in that the papermaking screen has areas used to produce separation fields, in which the paper-making screen the paper is shaped in such a way that that in these areas the deposition of fibers is reduced or increased, whereby a watermark can be obtained on the paper produced by the papermaking screen.

Preferably, in the areas used for the production of the information-carrying strips, the papermaking screen is shaped such that the deposition of the fibers is not significantly altered in these areas, so that the paper produced by the papermaking screen is not watermarked.

In another preferred embodiment, the papermaking screen is embossed in the areas used to produce the information-carrying strips, thereby increasing the fiber settling in these areas, whereby a watermark can be obtained on the paper produced by the papermaking screen.

Preferably, the papermaking wire is embossed into at least one of its areas used to form the separation fields, thereby increasing fiber deposition.

Due to this, it is possible to obtain a watermark on the paper produced by the paper-making screen.

In another preferred embodiment, the papermaking wire is electroplated in at least one of its regions used for producing the separating fields, which reduces the deposition of fibers, whereby a watermark can be obtained on the paper produced by the papermaking wire.

Preferably, the areas of the papermaking screen used to form the separation fields are narrower than the areas of the papermaking screen used to form the information conveying strips.

According to the invention, the separation fields which separate the information conveying stripes from one another are designed as clearly detectable watermarks. Said separator fields are detected by the bar code reader as stripes (separator fields). The actual information carried by the bar code is, however, not determined by the width of the detected bars (separator boxes), but by the widths of the fields between the detected bars (separators), these fields being the actual information contained in the bar code. This means that both the beginning and the end of the bars carrying information are marked with bars in the form of separating fields.

This means two significant advantages over the solutions known in the state of the art. First, the information-carrying barcode strips between the dividers can be any width. Since the brightness of the information transfer strips is not taken into account when testing them, there is no problem with an unevenly filled surface of the strip which appears darker or lighter when light passes through it. Secondly, the separating fields can be very narrow, in particular when formed by electroplating on a papermaking wire, so that the overall length of the barcode is relatively short, saving valuable space.

In order to further limit the length of the bar code, it is preferable to form it in the form of a two-dimensional bar code which has several, for example, information paths parallel to each other.

In a particularly advantageous embodiment of the invention, the fields between the separating fields that form the actual stripes carrying the bar code information are not designed as a watermark, so that in transmitted light only the separating fields can be recognized as watermarked stripes. The first and last separators define the boundaries of the bar code.

In order to increase the contrast, the information conveying bar code stripes may also be designed as watermarks, the separator fields being light watermarks and the information conveying stripes dark watermarks, or vice versa. Preferably, the form of the watermarks is not information strips, but dividers, since light strips carrying information can cause the risk of holes in the paper when the width of the strips increases.

In a particular embodiment of the invention, the separating field located at the edge of the bar code, which means that it is the first or last separating field, determines, for example, by using its characteristic width or fiber density, the information content assigned to stripes of different width, i.e. whether it is for a wide strip the value "1" is assigned, and the value "0" is assigned to the narrow bar, or vice versa. Alternatively, the first strip may be the start bit and its width may determine whether the wide strip is assigned a value of "1", and the narrow strip is assigned a value of "0", or vice versa.

In a preferred embodiment, the document in need of security or value document according to the invention is provided with an additional medium enabling the storage of information. This may be, for example, a magnetic storage medium such as a magnetic stripe, or an electronic medium such as a chip containing integrated circuits. In such an embodiment, the bar code may contain data related to the encryption and decryption of information instead of the document value. In the information storage medium, a document value that can be retrieved from the bar code information and the serial number of the document or the result of combining the ratio value and serial number in a predetermined manner may advantageously be stored in the information storage medium. As a result, the level of protection against forgery and the possibility of checking the authenticity of the document is increased. Save the result

The connections may be made during the production of the document or at the time of its introduction into circulation. During the authenticity checking, the connection result can be read from the information storage medium. If the connection method is known, the use of a document value that can be read very easily with a barcode in the form of a watermark allows the serial number to be retrieved. If the serial number is additionally read directly from the document, a further possibility arises to verify that the data read from the information storage medium actually relates to that specific document, which may be, for example, a banknote.

Convergence of parameters related to the formation of the bar code according to the invention, such as the opacity of the paper in the area of ​​the bar code or the irregularity of the edges of its individual parts, can also be used as additional measured values, in order to increase the level of security against forgery and to improve the possibility of checking for authenticity.

The invention will now be described by way of example with reference to the accompanying drawings, in which:

Fig. 1 shows a banknote having a watermark barcode according to the invention, Fig. 2 shows a view of a watermark barcode according to the invention with light passing through it, Fig. 3 shows a further watermark barcode according to the invention with passing light. through it, fig. 4 schematically shows a cross-section of the papermaking screen, fig. 5 is a graph of the intensity of light transmitted through a first embodiment of a watermark in the form of a watermark according to the invention, Fig. 6 is a graph of the intensity of light transmitted through a second embodiment of a watermarked barcode according to the invention, Fig. 7 is a graph of the intensity of light transmitted through a third embodiment of a barcode in the form of a watermark according to the invention, fig. 8 is a view of a prior art bar code in the form of a watermark with light passing through it, Fig. 9 is a graph of the intensity of light passing through a prior art bar code in the form of a watermark, and Fig. 10 is a graph of the intensity of light passing through another prior art barcode in the form of a watermark.

Fig. 1 shows by way of example one of many possible value documents and documents requiring security in the form of a banknote 1 with a denomination 2 of "100 Euro". The banknote 1 has a two-dimensional barcode 3 which is incorporated in the form of a watermark into the paper from which the banknote 1 is made.

Value documents having a one-dimensional barcode in the form of a watermark are already known in the prior art. The wider the stripes are introduced into the paper in the form of a watermark, the more irregular their appearance in the light passing through them, which makes it very difficult to test the stripes. This is seen in Fig. 8, which schematically shows the bar code in the form of a watermark 3 viewed in the light passing through it. The barcode 3 has been produced by using an embossed papermaking screen in which the embossed areas corresponding to the bars 5 of the barcode 3 promote the deposition of the paper fibers. Fiber density, i.e. however, the thickness of the paper decreases towards the inner surface regions of the strip, which makes the edge regions of the strip clearly visible, but the inner regions of this surface appear brighter in light passing through it compared to the edge regions. This is shown graphically in Fig. 9, where in the plot the transmitted light intensity I +, I^- differs from the usual transmitted light intensity Ig. It can be seen that the transmitted light intensity I in the center of the stripes is closer to the normal transmitted light intensity Ig the wider the strip. It should be noted here that the normal Ig transmitted light intensity value in FIG. 9 is represented in an idealized manner. In fact, said value | g is variable and differs from the mean value, so that with wide stripes it may happen that the barcode sensor signals the end of the strip 5 or the start of the separator field 6, even though

Only the center of the strip 5 is reached. This can lead to reading errors as the wide strip 5 may be mistakenly interpreted as two narrow stripes.

The alternative solution of using a light bar code instead of a dark bar code has a drawback, namely that the fiber density is reduced towards the center of the bar. As a result, again, a strip with a constant brightness and the desired dimensions is not obtained. Moreover, in the case of wide stripes, there is a risk of holes forming in the paper.

Fig. 10 shows the intensity of the light transmitted through the bar code disclosed in DE 30 34 916 A1, where the above-described problems do not occur. According to this patent, the areas of the papermaking wire used to form the barcode are embossed into the papermaking wire in the form of rectangular, non-equilateral triangles. The part of the watermark that is produced in the paper with the steep edge is easily recognizable as a characteristic light or dark stripe and marks the beginning of the stripe 5. Whether stripe 5 corresponds to the value "1" or the value "0" does not depend on the width, but on whether the strip is light or dark, which means it depends on whether the embossing in the papermaking wire, starting from the paper level, is facing down or up. As a result, it is also possible to keep the length of the barcode short, since it is not necessary to use the separating fields 6 between the individual bars 5 in order to clearly delimit them. However, a disadvantage is that the bar code is limited to binary encoding only, since only light and dark fields are distinguished.

Figures 2 and 3 show portions of different embodiments of the barcode in the form of the watermark 3 shown in Figure 1, which is seen along the line AA in the light passing through it. In both of these cases, as well as in the examples below, the bar code is in the form of a binary bar code consisting of zeros and ones, with the value "0" or "1" indicating the width of the strip. The bars 5 are separated from each other by separating fields 6, with the first and last separating fields defining the boundaries of the bar code. The barcodes shown in Figs. 2 and 3 can thus be read as a sequence of values ​​0-1-1-0.

In the embodiment shown in Fig. 2, the separation areas 6 appear darker compared to the strips 5. This means that in the areas of the separation areas 6 the note has an increased fiber density, which is achieved by corresponding embossing in the papermaking wire used for the production. the paper from which the banknote is made. Said embossing of the papermaking wire causes increased deposition of the paper fibers during the papermaking process, whereby the observed intensity of the light passing through these areas is reduced and the separation fields 6 appear darker. The stripes 5 that define the actual information carried by the barcode do not appear lighter or darker in the light passing through them than the surrounding material of the banknote, since the strips 5 do not have any watermark characteristics. As the bar code reader therefore detects the information bars 5, but the separation fields 6, the width of the information bars is indirectly determined simply by the distance between the detected spacers 6.

The same applies to the embodiment shown in Fig. 3, where, unlike the embodiment shown in Fig. 2, the separator fields 6 of the barcode appear light, except at the extreme left-hand side. The extremely clear bright separating fields 6 can be produced using so-called galvanotypes. The galvanotypes are usually in the form of small metal parts that are attached to one side of the papermaking wire, which may for example be soldered or attached using staples that are pressed into the mesh of the screen and then folded. In this way, it is possible to obtain very narrow and traversed light effects that are easy to detect with the aid of sensors.

The leftmost separating field 6 in Fig. 3 specifies that the next wide stripes should be read as "1" as the narrow stripes 5, as is the case in FIG. 2. If the leftmost separating field 6 were formed as clear separator field, like all other 6 separator fields, the information contained in bars 5 should be reversed, so all information contained in the barcode will not be read as 0-1-1-0, but as 1-0-0-1 .

Instead of characterizing the transmitted light intensity or the fiber density of the leftmost separating field 6-, it may also be the rightmost separating field 6-, the width of the separating field can also be used to define the formations contained in the wide and narrow stripes 5. The above two possibilities may be combined with each other, in particular for determining further information regarding the bar code.

Alternatively or additionally also the first or last strip 5 may be used as a start bit or a stop bit, for example whether wide stripes should be read as "0" and narrow stripes as "1" or vice versa can convey the width of the strip as a bit. start or stop bit.

Fig. 4 shows, by way of example, a schematic representation of a part of a papermaking wire 8 that can be used to produce paper having the watermark barcode shown in Fig. 3. To this end, the papermaking wire 8 has galvanotypes 7 arranged in a suitable manner on the surface used for papermaking and making it possible to obtain bright separating fields 6, as well as a deep-embossed area 9 to form the leftmost separating field 6, in which the paper has an increased thickness. or the density of the fibers, making the field appear dark in the light passing through it.

Fig. 5 shows an idealized course of the light intensity plot passing through a bar code similar to that shown in Fig. 2, using dark separating fields 6 and information conveying stripes 5. The intensity of the transmitted light I in the areas of separating fields 6 is lower than the normal intensity of the transmitted light. Jg through the banknote paper, since the fiber density F is correspondingly higher in the areas of the separating fields 6. The diagram of the intensity of transmitted light I is thus consistent with the diagram of the density of the fibers F, if the increase in intensity of J + in the diagram corresponds to the upward direction, and the increase in density of the fibers F + corresponds to the direction of downward. The graphs of transmitted light intensity and fiber density are therefore both designated by the reference number 4.

Fig. 6 shows plots of transmitted light intensity and fiber density for a barcode similar to that shown in Fig. 3. Here, the transmitted light intensities I_ are in the areas of separating fields 6 greater than the normal transmitted light intensity Jo, except for the leftmost separating field 6. for which the transmitted light intensity I is less than the normal transmitted light intensity Ig. Contrary to fig. 5, the transmitted light intensity diagram shown in Fig. 6 is shown in a less idealized way, so it can be seen that the transmitted light intensity and fiber density, despite the substantially regular distribution of Ig, Fg in the strip 5 forming part of the barcode slightly deviate from the mean value. Ig or Fg, which correspond to "normal transmitted light intensity" and "overall fiber density".

Fig. 7 shows a further embodiment of the invention. Basically it is a combination of the prior art solution shown in Fig. 9 and the embodiment shown in Fig. 6 or Fig. 3. This means that the separating fields 6 as well as the stripes 5 are incorporated into the paper in the form of watermarks, the information conveying stripes 5 in transmitted light having the appearance of dark areas having slightly lighter central portions, which at the beginning of the description are shown as unfavorable, the partitions 6 have the appearance of clear bright lines that are easy to recognize. The particularly high intensity of the light passing through the regions of separating fields 6 is so much higher than that of the light passing through the brighter central parts of the information-carrying stripes 5 that the erroneous reading described at the beginning is excluded. The embodiment shown in fig. 7 provides in comparison with the embodiments shown in fig. 5 and fig. 6 or fig. 2 and fig. 3 an additional increase in the contrast between the areas of the bars 5 and the separator fields 6, whereby the readability of the bar code is improved.