OA20541A - Method for producing a security feature. - Google Patents

Abstract

The invention relates to a method for producing a security feature (1) in the form of a colored image (2), a colorant being applied to a substrate (3) to produce the image, the image (2) being subdivided into grid areas, immediately adjacent grid areas (4, 5, 6, 9, 10, 11) of the image (2) partially overlapping, an overlapping area (7, 8) of immediately adjacent grid areas (4, 5, 6, 9, 10, 11) being smaller than one of the grid areas (4, 5, 6, 9, 10, 11), grid areas (4, 5, 6, 9, 10, 11) of the image (2) being each assigned at least one color, and at least the areas of the substrate (3) corresponding to the respective grid areas (4, 5, 6, 9, 10, 11) minus the corresponding overlapping areas (7, 8) being covered with at least one colorant of the respectively assigned color, the overlapping areas (7, 8) between adjacent grid areas (4, 5, 6, 9, 10, 11) being covered at least with the colorant having the color assigned to one of the grid areas (4, 5, 6, 9, 10, 11) overlapping in the respective overlapping areas (7, 8).

Description

METHOD OF PRODUCING A SECURITY FEATURE

The invention relates to a method of producing a security feature in the form of a colored image, wherein a colorant îs applied to a sub strate to produce the image accordîng to the preamble of claim 1.

Furthermore, the invention relates to a security feature in tire form of a colored image accordîng to the preamble of claim 1.

In addition, the invention has as an object a security element, in particular in the form of a security strîp.

In addition, the invention relates to a value document. A method and a security element of the above-mentioned type hâve become known from WO2007/09330Û12A2. Another security element, in which a complété overlap of adjacent grid areas is realized, has become known from EP3255417A1. EP0303725A1 and EP 3248806 Al relate to a security paper that has partially overlapping luminescent colors that are not visible under normal illumination.

When security features are produced using printing processes based on the CMYK color model, the colors are usualiy applied over the entire surface, resulting in subtractive color mixing. However, these printing processes are not suitable for implementing additive color mixing. In particular, when fluorescent inks are used, known printing processes based on full-surface overlapping of the ink layers lead to problems in the realization of colored images, since full-surface overlapping of the primary colors red, green and blue in the case of fluorescent colorants results in a gray overall impression. When only two fluorescent colors are used, on the other hand, one of the two colors is usualiy perceived more strongly than the other. With the known methods, it is therefore not possible to display colored images, for example in the form of portraits, landscapes, alphanumerîc characters, etc., with fluorescent colors. The display of fluorescent rainbows is an establîshed technique. Until now, rainbows hâve been produced using three block-strip cylinders that print in an overlapping manner to generate a color gradient in the form of a rainbow. However, it is not possible to display texts or individual letters or characters in the rainbow colors with the existing solutions.

It îs therefore an object to overcome the above-mentioned disadvantages of the prior art and to improve the production of security features with colored images.

The above-mentioned object is solved with a method of the type mentioned at the beginning according to the invention by tire features of the characterizing part of claim l.

The solution according to the invention enables the production of security features with colored images in a simple manner, even when fluorescent înks are used, since the only partial overlapping of the grid areas enables additive color mixing with luminous colorants. By varying the overlapping area of adjacent grid areas, the intensîty of the color impression at this point can be optimally adjusted so that the desired overall optical impression is achieved. The solution according to the invention can also be used to provide a rainbow display with designs, for example, non-fluorescent text, opposite rainbow, whîte text etc.

According to an advantageous variant of the invention, it may be provided that the image is divided in at least one partial area into at least two partially overlapping grid areas, at least one of the at least two grid areas being covered, at least outside the overlapping area, with a colorant having a color different from the color of the colorant covering the other of the at least two grid areas.

Arbitrary colored images can be produced by covering part of the grid areas at least partially with red color and part of the grid areas of the image at least partially with green color and part of the grid areas of the image at least partially with blue color.

According to an advantageous further embodiment of the invention, which is particularly suitable for production by means of an intaglio printing process, it may be provided that the grid areas are of the same size and shape.

In order to achieve optimum additive color mixing, fluorescent colorants, in particular a colorant that fluoresces in UV light can be used as colorants.

Particularly high luminosity and coverage can be achieved by transferring the colorant to the substrate using an intaglio printing process.

At least one character, in particular an alphanumeric character and/or icon and/or géométrie figure and/or symbo!, or a sequence of characters may be applied to produce the image.

The colorants can be applied overlapping in layers so that at least one sequence of colors in the image corresponds to the sequence of colors of a rainbow or a multicolor gradient.

According to a variant of the invention, a colored area may be at least partialiy generated around at least one character or the at least one sequence of characters by applyîng one or more colorants to grid areas surrounding the character.

Further, a sequence of colors in the at least one character or in the at least one sequence of characters may be applied in the opposite direction to a sequence of colors in the colored area.

The above-mentioned object can also be solved with a security feature of the type mentioned at the beginnîng according to the invention by the features of the characterizing part of claim 11.

Preferably, an image comprises, at least in a partial area, at least two overlapping grid areas, at least one of the grid areas being covered, at least outside the overlapping area, with a colorant having a color different from that of the colorant covering the other of the at least two grid areas.

The realîzation of images of any color is favored by the fact that part of the grid areas of the image is at least partialiy covered with red color, and part of the grid areas of the image is at least partialiy covered with green color, and part of the grid areas of the image is at least partialiy covered with blue color.

According to an advantageous variant of the invention, it may be provided that the grid areas formîng the image are of the same size and shape.

It has been found to be particularly advantageous that an overlapping area of two adjacent grid areas of the image is between I and 90% with respect to the size of a grid area.

A preferred variant of tire invention is that the colorant is a fluorescent colorant, in particular a colorant that fluoresces in UV light.

The image is preferably a portrait, a landscape, an abstract géométrie sign, a logo or an alphanumeric character, or a coding.

In addition, a colored area can be arranged at least partially around the at least one character or the at least one sequence of characters.

A sequence of colors in which at least one character or in which at least one sequence of characters is included may be applied in the opposite direction to a sequence of colors in the colored area.

According to a variant of the invention, the colorants may be applied overlapping in layers so that at least one sequence of colors in the image corresponds to the sequence of colors of a rainbow or a multicolor gradient.

The object of the invention is also solved by a security element, in particular in the form of a security strip, which has a security feature according to any one of claims 11 to 20.

The object mentioned at the beginning can also be solved by a value document comprising a security element according to claim 21 and/or a security feature according to one of claims 11 to 20.

For a better understanding of the invention, it îs explained in more detail with reference to the following figure.

It shows in a highly simplified, scheniatic représentation:

Fig. 1 security feature according to the invention.

By way of introduction, it should be noted that in the differently described embodiments, the sanie parts are provided with the saine reference signs or the sanie component désignations, whereby the disclosures contained in the entire description can be transferred mutatis mutandis to the same parts with the sanie reference signs or the saine component désignations. Also, the positional indications selected in the description, such as top, bottom, side, etc., are related to the immediately described as well as depicted figure, and these positional indications are to be transferred mutatis mutandis to the new position in the event of a change of position.

Ail indications of value ranges in the présent description are to be understood as including any and ail subranges thereof, e.g. the indication 1 to 10 is to be understood as including ail subranges starting from the lower limit 1 and the upper limit 10, i.e. ail subranges starting with a lower limit of 1 or greater and ending with an upper limit of 10 or less, e.g. 1 to 1.7, or 3.2 to 8.1, or 5.5 to 10.

According to Fig. 1, a security feature 1 according to the invention has the form of a colored image 2, for example in the foim of a portrait, a landscape, a building, an abstract géométrie character, a logo or an alphanumerîc character 3, or a sequence of characters, etc. The security feature 2 is applied to a substrate, for example a security strip or immediately to a value document.

The image 2 is divided into grid areas 4, 5, 6, 9, 10, 11. The grid areas 4, 5, 6, 9, 10, 11 forming the image 2 can be of the same size and shape. Deviating from the shape shown here, the grid areas 4, 5, 6, 9, 10, 11 may hâve a triangular, square or polygonal contour. Thus, the contours of the grid surfaces 4, 5, 6, 9, 10, 11 can be formed in particular by triangles, rectangles, parallelograms, trapezoids, deltoids, hexagons, octagons, or any polygons.

It can be seen from the illustration that adjacent grid areas 4, 5, 6, 9, 10, 11 of the image 2 partially overlap, wherein an overlapping area 7, 8 of two adjacent grid areas 4, 5, 6, 9, 10, 11 is smaller than each of the grid areas 4, 5, 6, 9, 10, 11 per se. An overlapping area of two adjacent grid areas 4, 5, 6, 9, 10, 11 of the image 2 is preferably between 1 and 90%, in particular between 3 and 80%, particularly preferably between 1 - 25% or 5 - 10%, with respect to the size of a grid area 4, 5, 6, 9, 10, 11.

According to Fig. 1, each grid area 4, 5, 6, 9, 10, 11 of the image 2 is covered with a colorant of a color associated with the respective grid area at least outsîde the overlapping areas 7, 8 to its adjacent grid areas 4, 5, 6, 9, 10, 11.

Here, a partial area of the grid areas 4, 5, 6, 9, 10, 11 can be differently colored. Each of the grid areas 4, 5, 6, 9, 10, 11 can be single-colored outside the overlapping areas 7, 8 to the adjacent grid cells. In an overlapping area 7, 8, for example, that colorant can be applied which corresponds in color to the colorant of one of the overlapping grid areas 4, 5, 6, 9, 10, 11 outside the overlapping area 7, 8. In this embodiment, the overlapping area 7, 8 is thus covered with only one colorant layer, which corresponds to that covering one of the adjacent grid areas 4, 5, 6, 9, 10, 11. Thus, the grid area 5 outside the overlapping area 7 can be completely green, while the overlapping area 7 and the grid area 6 can be completely covered with a colorant of blue color.

Alternatively, however, each grid area 4, 5, 6, 9, 10, 11 can be covered individually over its entire surface with a colorant of one color, with layers of the different colorants coming to lie on top of one another in an overlapping area of the grid areas 4, 5, 6, 9, 10, 11. For example, the frrst grid area 4 can be covered with red color over its entire surface, the second grid area 5 can be covered with green color over its entire surface, and the thîrd grid area 6 can be covered with blue color. In an overlapping area of the three grid areas 4, 5, 6, the layer structure is thus redgreen-blue, depending on the sequence in which the colorant is applied.

In other partial areas of the image 2, however, adjacent grid areas 9, 10, 11 can be covered with the same color, for example blue, red or green.

lire preferred colorant is a fluorescent colorant, in particular a colorant tirât fluoresces in UV light. Inks with fluorescent pigments, for example, hâve proven to be particularly suitable.

To produce the security feature 1 shown in Fig. 1, the image 2 is created by applying colorant to the substrate. The image 2 is divided into grid areas 4, 5, 6, 9, 10, 11. Adjacent grid areas 4, 5, 6, 9, 10, 11 partîally overlap each other, wherein the size of the overlapping area 7, 8 of two adjacent grid areas 4, 5, 6, 9, 10, 11, as already mentioned above, is preferably between 1 and 90%, in particular between 3 and 80%, particularly preferably between I - 25% or 5 - 10%, with respect to the size of a grid area 4, 5, 6, 9, 10, 11.

Partîally overlapping grid areas can be covered with different colors. For example, grid area 4 can be covered with a fluorescent red, grid area 5 with a fluorescent green and grid area 6 with a fluorescent blue.

If the grid areas 4, 5, 6 are covered with colorants over their entire surface in succession, three layers of the colorants used may overlap in corner areas of the grid areas. Thus the layer se quence red. green, blue can resuit in a corner intersection area of the grid areas 4, 5, 6, while the layer sequences red and green can resuit in a sîde edge intersection area between the grid areas 4 and 5 and the layer sequence green and blue can resuit in a side edge intersection area between the two grid areas 5 and 6. This type of image transfer to the substrate can also be carried out, for example, using a digitally controlled inkjet printing method.

As an alternative to a full-surface coating of the grid areas 4, 5, 6, 9, 10, 11 carried out in succession, however, only a section of one of the grid areas 4, 5, 6, 9, 10, 11 located outside the overlapping area 7, 8 can be covered wîth a colorant of a first col or and another of the grid areas 4, 5, 6, 9, 10, 11 as well as the overlapping area 7, 8 with a colorant of a second color. Thus, in the corner intersection area of the grid areas 4, 5, 6 as well as in the latéral overlapping areas only a blue color layer, as in the grid area 6, could be applied. while the remaining part of the grid area 4 could be colored red and the remaining part of the grid area 5 could be colored green. For the embodiment example described in this paragraph, an intaglio printing process is particularly suitable, whereby an intaglio printing cylinder can be used, the cells of which are formed according to the contour of the grid areas 4, 5, 6, 9, 10, 11, taking into account the overlapping areas 7, 8.

It applies for ail embodiments described above, that adjacent and partially overlapping grid areas 9, 10, 11 can also be covered with a colorant of the same color, for example a fluorescent blue, red or green in partial areas of the image 2.

To produce the image 2 shown in Fig. 1, a character or a sequence of characters 3 may be applied to the substrate. The characters may be, for example, alphanumerîc characters and/or icons, such as hîeroglyphics and the like, and/or géométrie figures and/or symbols. Each character 3 may additionally be surrounded by a colored area.

At least some of the grid areas 4, 5, 6, 9, 10, 11 can also be coated partially or completely and/or in overlapping areas 7, 8 with adjacent grid areas 4, 5, 6, 9, 10, 11 with two or more layers of colorants of different colors. With this embodiment, a continuons color gradient can be achîeved in the individual characters 3. The character 3 or the sequence of characters, as well as any surrounding colored areas, are dividcd into the grid areas. In addition, géométrie area coverage of the colorants used in the image 2 can vary. For example, in one grid area of the grid areas 4, 5, 6, 9, 10, 11, at least a first layer of a first color and at least a second layer of a second color may be applied there over, the second layer covering a first surface area, for example 20%, of the first layer. In another grid area of the grid areas 4, 5, 6, 9, 10, 11, two corresponding layers of the first and the second color may also be applied, the second layer covering a second surface area of a different size, for example 10%, of the first layer. The area coverages in the grid areas 4, 5, 6, 9, 10, 11 are selected here in such a way that the desired color impression or color gradient is achieved in the image 2.

Furthermore, as an alternative or in addition to varying the géométrie area coverage, the thickness of the layers applied one on top of the other can also be varied in order to achieve the desired color impression. Thus, in a first grid area ofthe grid areas 4, 5, 6, 9, 10, 11, a first layer may hâve a first thîckness and a second layer located thereunder may bave a second thickness, while, for example, in another grid area of the grid areas 4, 5, 6, 9, 10, 11, a first or second layer may be thicker or thinner than the corresponding first or second layer of the first grid area.

The colorants can, for example, be applied in layers overlapping in the grid areas 4, 5, 6, 9, 10, 11 in such a way that at least one sequence of colors in the image 2, e.g. in the sequence of characters 3 and/or a colored area surrounding them, corresponds to the sequence of colors of a rainbow. Preferably, colors of the RGB color space are used here. For the production ofthe image 2, for example, an intaglio printing process can be used in which three cylinders are used, each of which successîvely applying a colorant of one color to the substrate. Thus, one of the cylinders can apply a colorant of red color, another cylinder can apply a colorant of green color, and yet another cylinder can apply a colorant of bine color. The colorants are fîlled înto cells of the cylinders in a manner known per se, and excess color is wiped off from the webs of the cylinders located between the cells. The outlines ofthe cells can define the grid areas 4, 5, 6, 9, 10, Il this connection applies generally to ail embodiments of the invention în which an intaglio printing process is used. The cylinders are coordinated with one another in such a way that the desired coverage with colorant or the desired color gradient on the substrate is achieved. The solution according to the invention makes it possible to display characters with any color gradient, for example a continuous color gradient.

A sequence of colors in the at least one character 3 or in the one sequence of characters may also be opposite to a sequence of colors in the colored area.

Final ly, for the sake of order, it should be noted that, for a better understanding of the layout, éléments hâve been shown partial ly ont of scale and/or enlarged and/or reduced in size.

The invention is not limited to the embodiment/s illustrated in the drawîngs. Accordingly, it should be understood that where features mentîoned in the appended claims are followed by reference signs, such signs are included solely for the purpose of enhancing the intelligibility of the claims and are in no way limiting on the scope of the claims.

List of reference signs

1	Security feature
2	Image
3	Substrate
4	Grid area
5	Grid area
6	Grid area
7	Overlapping area
8	Overlapping area
9	Grid area
10	Grid area
11	Grid area

Claims (23)

1, A method for producing a security feature (1) in the form of a colored image (2), a colorant being applied to a substrate to produce the image, the image (2) being subdivided into grid areas the image (2) is subdivided into grid areas, immediately adjacent grid areas (4, 5, 6, 9, 10, 11) of the image (2) partially overlapping, an overlapping area (7, 8) of immediately adjacent grid areas (4, 5, 6, 9, 10, 11) being smaller than one of the grid areas (4, 5, 6, 9, 10, 11), grid areas (4, 5, 6, 9, 10, 11) of the image (2) being each assigned at least one color, and at least the areas of the substrate (3) corresponding to the respective grid areas (4, 5, 6, 9, 10, 11) minus the corresponding overlapping areas (7, 8) being covered with at least one colorant of the respectively assigned color, characterized in that the overlapping areas (7, 8) between adjacent grid areas (4, 5, 6, 9, 10, 11) are covered with the colorant having the color assigned to one of the grid areas (4, 5, 6, 9, 10, 11) overlapping in the respective overlapping areas (7, 8).

2. The method according to claim 1, characterized in that the image (2) is divided in at least one partial area into at least two partially overlapping grid areas (4, 5, 6, 9, 10, 11), at least one of the at least two grid areas (4, 5, 6, 9, 10, 11) being covered, at least outside the overlapping area (7, 8), with a colorant having a color different from the color of the colorant covering the other of the at least two grid areas (4. 5, 6, 9, 10, 11).

3. Method according to daim 1 or 2, characterized in that a part of the grid areas (4) is covered at least partially with red color and a part of the grid areas (5) of the image (2) is covered at least partially with green color and a part of the grid areas (6) of the image (2) is covered at least partially with blue color.

4. The method according to any one of daims 1 to 3, characterized in that the grid surfaces (4, 5, 6, 9, 10, 11) are of the same size and shape.

5. The method according to any one of daims 1 to 4, characterized in that fluorescent colorants, including colorants fluorescent in UV light, are used as colorants.

6. The method according to any one of daims 1 to 5, characterized in that the colorant is transferred to the substrate by means of an intaglio printing process.

7. The method according to any one of daims I to 6, characterized in that at least one character (3), including an alphanumeric character (3) and/or an icon and/or a géométrie figure and/or a Symbol, or a sequence of characters, is applied to produce the image (2).

8. The method according to any one of daims 1 to 7, characterized in that the colorants are applied overlapping în layers so that at least one sequence of colors in the image (2) corresponds to the sequence of colors of a rainbow or a multicolor gradient.

9. The method according to any one of daims 7 or 8, characterized in that a colored area is at least partially generated around the at least one character (3) or the at least one sequence of characters by applying one or more colorants to grid areas (4, 5, 6, 9, 10, 11) surrounding the character (3).

10. The method according to claim 9, characterized in that a sequence of colors in the at least one character (3) or in the at least one sequence of characters is applied in the opposite direction to a sequence of colors în the colored area.

11. Security feature în the form of a colored image (2), characterized in that it is produced by a method according to daims 1 to 10 and the image is divided into colored grid areas (4, 5, 6, 9, 10, 11), adjacent grid areas (4,5,6, 9, 10, 11) of the image partially overlapping and an overlapping area (7, 8) of adjacent grid areas (4, 5, 6) beîng smaller than one of the grid areas (4, 5, 6, 9, 10, 11) per se, wherein at least one color is assigned to each of the grid areas ofthe image and at least the areas of the substrate corresponding to the respective grid areas minus the corresponding overlapping areas are covered with at least one colorant of the respectively assigned color, wherein the overlapping areas between adjacent screen areas are covered with the colorant having the color assigned to one of the grid areas overlapping in the respective overlapping areas.

12. The security feature according to daim 11, characterized in that an image (2) comprises, at least in a partial area, at least two overlapping grid areas (4, 5, 6, 9, 10, 11 ), at least one of the grid areas (4, 5, 6, 9, 10, 11) being covered, at least outside the overlapping area, with a colorant having a color different from that of the colorant covering the other of the at least two grid areas (4, 5,6, 9, 10, 11).

13. Security feature according to claim 11 or 12, characterized in that a first grid area (4) of the image (2) is at least partially covered with red color and/or a second grid area (5) of the image (2) is at least partially covered with green color and/or a third grid area (6) of the image (2) is at least partially covered with blue color.

14. Security feature according to any one of daims 11 to 13, characterized in that the grid areas (4, 5, 6, 9,10, 11) forming the image (2) are of the same size and shape.

15. Security feature according to any one of daims 11 to 14, characterized în that the overlapping area (7, 8) of two adjacent grid areas (4, 5, 6, 9, 10, 11 ) of the image (2) is between 1 and 90% with respect to the sîze of a grid area (4, 5, 6, 9, 10, 11).

16. The security feature according to any one of daims 11 to 15, characterized in that the colorant is a fluorescent colorant.

17. The security feature according to claim 16, characterized in that the colorant is a colorant that fluoresces in UV light.

18. The security feature according to any of daims H to 17, characterized in that the image (2) comprises a portrait, a landscape, an abstract géométrie sign, a logo or an alphanumerîc sign and/or an icon and/or a coding and/or a character or a sequence of characters.

19. The security feature according to claim 18, characterized in that a colored surface is arranged at least partially around the at least one character (3) or the at least one sequence of characters.

20. The security feature according to daim 18 or 19, characterized in that a sequence of colors in the at least one character (3) or in the at least one sequence of characters is applied in the opposite direction to a sequence of colors in the colored area.

21. The security feature according to daim 20, characterized in that the colorants are applied overlapping in layers so that at least one sequence of colors in the image corresponds to the sequence of colors of a rainbow or a multicolor gradient.

22. A security element, including a security element in the form of a security strip, characterized in that it has a security feature (!) according to one of daims 11 to 20,

23. A value document, characterized in that it comprises a security element according to daim 5 22 and/or a security feature (1) according to one of daims 11 to 21.