EP3877193B1 - Method for producing a security feature - Google Patents

Description

The invention relates to a method for producing a security feature in the form of a colored image, wherein a colorant is applied to a substrate to produce the image, according to the preamble of claim 1.

Furthermore, the invention relates to a security feature in the form of a colored image, according to the preamble of claim 11.

The subject of the invention is also a security element, in particular in the form of a security strip.

In addition, the invention relates to a document of value.

A method and a security element of the type mentioned above is from WO 2007/093300 A2 known. Another security element, in which a complete coverage of adjacent grid areas is realized, is from EP3255417A1 known. the EP0303725A1 and the EP 3248806 A1 relate to a security paper which has partially overlapping luminescent colors which are not visible under normal lighting.

In the production of security features using printing processes based on the CMYK color model, the colors are usually applied over the entire surface, which results in a subtractive color mixture. However, these printing methods are not suitable for the realization of an additive color mixture. Known printing processes based on full-area coverage of the color layers lead to problems in producing colored images, particularly when using fluorescent colors, since full-area coverage of the primary colors red, green and blue results in a gray overall impression with fluorescent colorants. On the other hand, when only two fluorescent colors are used, one of the two colors is usually perceived more strongly than the other. It is therefore not possible with the known methods to display colored images, for example in the form of portraits, landscapes, alphanumeric characters, etc., with fluorescent colors. The representation of fluorescence rainbows is a well-established one Technology. So far, rainbows have been produced with three block stripe cylinders that print overlapping and thus generate a color gradient in the form of a rainbow. However, it is not possible with the existing solutions to display text or individual letters or characters in the colors of the rainbow.

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

The above-mentioned object is achieved according to the invention with a method of the type mentioned by the features of the characterizing part of claim 1.

The solution according to the invention enables the production of security features with colored images in a simple manner, even when using fluorescent colors, since the only partial overlapping of the raster areas enables additive color mixing with luminous colorants. The intensity of the color impression can be optimally adjusted at this point by varying the overlapping area of adjacent grid areas, so that the desired overall visual impression is achieved. With the solution according to the invention, a rainbow display can also be provided with designs. e.g. non-fluorescent text, reverse rainbow, white text etc.

According to an advantageous variant of the invention, it can be provided that the image is subdivided in at least one partial area into at least two partially overlapping raster areas, with at least one of the at least two raster areas being coated at least outside the overlapping area with a colorant which is one of the color of the other of the at least two latching areas covering colorant has a different color is covered.

Any color images can be produced by covering part of the halftone areas at least partially with red paint and some of the halftone areas of the image at least partially with green paint and part of the halftone areas of the image at least partially with blue paint.

According to an advantageous development of the invention, which is particularly suitable for production using an intaglio printing process, it can be provided that the grid areas are of the same size and shape.

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

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

At least one character, in particular an alphanumeric character and/or icon and/or geometric figure and/or symbol, or a sequence of characters can be applied to produce the image.

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

According to one variant of the invention, a colored area can be generated at least partially around the at least one character or the at least one character sequence by applying one or more colorants to the grid areas surrounding the character.

Furthermore, a sequence of colors in the at least one character or in the at least one character string can be applied in opposition to a sequence of colors in the colored area.

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

Provision is preferably made for an image to comprise at least two overlapping raster areas, at least in a partial area, with at least one of the raster areas being coated at least outside the overlapping area with a colorant which is a different color from the color of the colorant covering the other of the at least two raster areas. is covered.

The realization of images of any color is favored by the fact that part of the raster areas of the image are at least partially covered with red paint and part of the raster areas of the image are at least partially covered with green paint and part of the raster areas of the image are at least partially covered with blue paint.

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

It has been found to be particularly advantageous that an overlapping area of two adjacent raster areas of the image is between 1 and 90%, based on the size of a raster area.

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

The image is preferably a portrait, landscape, abstract geometric character, logo, or alphanumeric character or code.

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

A sequence of colors containing at least one character or at least one character string can be applied in opposition to a sequence of colors in the colored area.

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

The object on which the invention is based is also achieved by a security element, in particular in the form of a security strip, according to claim 21.

The object mentioned at the outset is also achieved by a document of value according to claim 22.

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

Fig. 1

ein erfindungsgemäßes Sicherheitsmerkmal.

It shows in a highly simplified, schematic representation:

1

a security feature according to the invention.

As an introduction, it should be noted that in the differently described embodiments, the same parts are provided with the same reference numbers or the same component designations, with the disclosures contained throughout the description being transferred to the same parts with the same reference numbers or the same component designations can. The position information selected in the description, such as top, bottom, side, etc., is related to the directly described and illustrated figure and these position information are to be transferred to the new position in the event of a change in position.

All information on value ranges in the present description is to be understood in such a way that it also includes any and all sub-ranges, e.g. the information 1 to 10 is to be understood in such a way that all sub-ranges, starting from the lower limit 1 and the upper limit 10, are also included , i.e. all subranges start with a lower limit of 1 or greater and end 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 1 a security feature 1 according to the invention has the form of a colored image 2, for example in the form of a portrait, a landscape, a building, an abstract geometric character, logo or an alphanumeric character 3, or a sequence of characters etc. The security feature 2 is applied to a substrate, for example a security strip, or directly to a document of value.

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 can have a triangular, square or polygonal contour. The contours of the grid areas 4, 5, 6, 9, 10, 11 can be formed in particular by triangles, rectangles, parallelograms, trapezoids, deltoids, hexagons, octagons, or any desired polygons.

It can be seen from the illustration that adjacent grid areas 4, 5, 6, 9, 10, 11 of image 2 partially overlap, with an overlapping area 7, 8 of two adjacent grid areas 4, 5, 6, 9, 10, 11 being smaller than each of the grid areas 4, 5, 6, 9, 10, 11 for themselves. 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%, based on the Size of a grid area 4, 5, 6, 9, 10, 11. According to 1 each raster area 4, 5, 6, 9, 10, 11 of the image 2 is covered with a colorant of a color assigned to the respective raster area, at least outside of the overlapping areas 7, 8 to its neighboring raster areas 4, 5, 6, 9, 10, 11 .

Here, a portion of the grid areas 4, 5, 6, 9, 10, 11 can be colored differently. Each of the grid areas 4, 5, 6, 9, 10, 11 can be monochrome outside of the overlapping areas 7, 8 to the adjacent grid cells. According to the invention, that colorant is applied in an overlapping area 7, 8 that corresponds in color to the colorant of one of the overlapping locking surfaces 4, 5, 6, 9, 10, 11 outside of 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 which covers one of the adjacent grid areas 4, 5, 6, 9, 10, 11. Thus, the raster area 5 outside of the overlapping area 7 can be colored green over its entire area, while the overlapping area 7 and the raster 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 completely covered with a colorant of one color, with layers of the different colorants in an overlapping area of the grid areas 4, 5, 6, 9, 10, 11 come to lie on top of each other. The first raster area 4 can, for example, be covered with red paint over the entire area and the second raster area 5 with green paint over the entire area and the third raster area 6 with blue paint. In an overlapping area of the three grid areas 4, 5, 6, the red-green-blue layer structure thus results depending on the order in which the colorant is applied. In other partial areas of the image 2, however, mutually adjacent raster areas 9, 10, 11 can also be covered with the same color, for example blue, red or green.

A fluorescent colorant, in particular a colorant that fluoresces in UV light, is preferably used as the colorant. For example, inks with fluorescent pigments have proven to be particularly suitable.

To produce the in the 1 illustrated security feature 1, the image 2 is generated by applying colorant to the substrate. Image 2 is divided into grid areas 4, 5, 6, 9, 10, 11 divided. Adjacent grid areas 4, 5, 6, 9, 10, 11 partially overlap one another, the size of the overlapping area 7, 8 of two adjacent grid areas 4, 5, 6, 9, 10, 11, as already mentioned above, preferably being between 1 and 90 %, in particular between 3 and 80%, particularly preferably between 1-25% or 5-10%, based on the size of a grid area 4, 5, 6, 9, 10, 11.

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

If the full-area coverage of the screen areas 4, 5, 6 with colorants is carried out one after the other, three layers of the colorants used can overlap in the corner regions of the screen areas. In a corner intersection area of the grid areas 4, 5, 6, the layer sequence red, green, blue can result, while in a side edge intersection area between the grid areas 4 and 5 the layer sequences red and green and in a side edge intersection area between the both grid areas 5 and 6 can result in the layer sequence green and blue. This type of image transfer to the substrate can also be carried out, for example, using a digitally controlled inkjet printing process.

As an alternative to a full-surface coating of the grid areas 4, 5, 6, 9, 10, 11 carried out in succession, according to the invention only a section of one of the grid areas 4, 5, 6, 9, 10, 11 located outside of the overlapping region 7, 8 is coated with a colorant a first color and another of the grid areas 4, 5, 6, 9, 10, 11 and the overlapping area 7, 8 are covered with a colorant of a second color. In the corner cut area of the grid areas 4, 5, 6 and in the lateral overlapping areas, only a blue color layer could be applied, as in the grid area 6, 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 . A gravure printing process is particularly suitable for the exemplary embodiment described in this paragraph, in which case a gravure printing cylinder can be used whose cells are designed in accordance with the contour of the screen areas 4, 5, 6, 9, 10, 11, taking into account the overlapping areas 7, 8.

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

To produce the in 1 In the image 2 shown, a character or a sequence of characters 3 can be applied to the substrate. The characters can be, for example, alphanumeric characters and/or icons, such as hieroglyphs and the like, and/or geometric figures and/or symbols. Each character 3 can also be surrounded by a colored area.

At least some of the grid areas 4, 5, 6, 9, 10, 11 can be partly or completely and/or in overlapping areas 7, 8 with adjacent grid areas 4, 5, 6, 9, 10, 11 also with two or more layers of different colorants color to be coated. A continuous color progression can be achieved in the individual characters 3 with this embodiment. Both the character 3 or the character string and any surrounding colored areas are divided into the grid areas. In addition, a geometric area coverage of the colorants used can vary in image 2. For example, in a 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 can be applied thereover, the second layer covering a first surface area of the first layer, for example 20%, overcast. In another grid area of the grid areas 4, 5, 6, 9, 10, 11 two corresponding layers of the first and the second color can also be applied, the second layer covering a second 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 in such a way that the desired color impression or color gradient in the image 2 is achieved.

Furthermore, as an alternative or in addition to varying the geometric 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 of the grid areas 4, 5, 6, 9, 10, 11, a first layer can have a first thickness and a second layer underneath has a second thickness, while, for example, in another grid area 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 overlapping layers in the grid areas 4, 5, 6, 9, 10, 11 so 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 , which corresponds to the sequence of colors in a rainbow. Colors of the RGB color space are preferably used here. To produce image 2, a gravure printing process can be used, for example, in which three cylinders are used, each of which successively applies a colorant of one color to the substrate. Thus, one of the cylinders can apply a red colorant, another cylinder can apply a green colorant and yet another cylinder can apply a blue colorant. The colorants are filled in the wells of the cylinders in a manner known per se and excess color is stripped off the webs of the cylinders located between the wells. The outlines of the cells can define the screen areas 4, 5, 6, 9, 10, 11--this relationship generally applies to all embodiments of the invention in which a gravure printing process is used. The cylinders are coordinated 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 enables characters to be displayed with any desired color gradient, for example a continuous color gradient.

A sequence of colors in the at least one character 3 or in the one character string can also be the opposite of a sequence of colors in the colored area.

Finally, for the sake of clarity, it should be pointed out that some elements are shown not to scale and/or enlarged and/or reduced in size for a better understanding of the structure.

list of reference numbers

1

security feature

2

picture

3

substrate

4

grid area

5

grid area

6

grid area

7

overlap area

8th

overlap area

9

grid area

10

grid area

11

grid area

Claims (22)

1. A method for producing a security feature (1) in the form of a colored image (2), wherein a colorant is applied to a substrate to produce the image, wherein the image (2) is subdivided into grid areas, wherein immediately adjacent grid areas (4, 5, 6, 9, 10, 11) of the image (2) partially overlap, wherein an overlapping area (7, 8) of immediately adjacent grid areas (4, 5, 6, 9, 10, 11) is smaller than one of the grid areas (4, 5, 6, 9, 10, 11), wherein grid areas (4, 5, 6, 9, 10, 11) of the image (2) are each assigned at least one color, and at least the areas of the substrate corresponding to the respective grid areas (4, 5, 6, 9, 10, 11) minus the corresponding overlapping areas (7, 8) are 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), wherein at least one of the at least two grid areas (4, 5, 6, 9, 10, 11) is 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. The method according to claim 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 one of claims 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 one of claims 1 to 4, characterized in that fluorescent colorants, in particular a colorant fluorescent in UV light, are used as colorants.
6. The method according to one of claims 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 one of claims 1 to 6, characterized in that at least one character (3), in particular an alphanumeric character (3) and/or an icon and/or a geometric figure and/or a symbol, or a sequence of characters is applied to produce the image (2).
8. The method according to one of claims 1 to 7, characterized in that the colorants are applied overlapping in 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 one of claims 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 in the colored area.
11. A security feature in the form of a colored image (2), characterized in that it is produced by a method according to claims 1 to 10 and the image is divided into colored grid areas (4, 5, 6, 9, 10, 11), wherein adjacent grid areas (4, 5, 6, 9, 10, 11) of the image partially overlap and an overlapping area (7, 8) of adjacent grid areas (4, 5, 6) is 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 of the 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 grid 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 claim 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), wherein at least one of the grid areas (4, 5, 6, 9, 10, 11) is 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. The 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. The security feature according to one of claims 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. The security feature according to one of claims 11 to 14, characterized in 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 size of a grid area (4, 5, 6, 9, 10, 11).
16. The security feature according to any one of claims 11 to 15, characterized in that the colorant is a fluorescent colorant, in particular a colorant that fluoresces in UV light.
17. The security feature according to one of claims 11 to 16, characterized in that the image (2) comprises a portrait, a landscape, an abstract geometric sign, a logo or an alphanumeric sign and/or an icon and/or a coding and/or a sequence of characters.
18. The security feature according to one of claims 11 to 17, 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.
19. The security feature according to one of claims 11 to 18, 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.
20. The security feature according to claim 19, 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.
21. A security element, in particular in the form of a security strip, characterized in that it has a security feature (1) according to one of claims 11 to 20.
22. A value document, characterized in that it comprises a security element according to claim 21 and/or a security feature (1) according to one of claims 11 to 20.

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