RU2419551C2 - Protective element - Google Patents

Abstract

FIELD: printing industry.

SUBSTANCE: invention relates to a protective element, a method of its manufacturing, a data carrier having such a protective element, and also to application of such a protective element or a data carrier for products protection. The protective element comprises a transparent base material, having the first periodical or almost periodical printed pattern of dots or lines on the first side, and on the second side, being substantially its mirror reflection, the second periodical or almost periodical printed pattern of dots or lines. The second printed pattern contains at least one subregion, where dots or lines are arranged with displacement relative to dots or lines of remaining second printed pattern of dots or lines. The first printed pattern of dots or lines is combined with a relief pattern, arranged by method of metallographic printing. At the same time the specified first printed pattern of dots or lines interacts with the second printed pattern of dots or lines so that at least one subregion comprises an element of information perceived when viewed in a passing light and indicating authenticity of a protective element.

EFFECT: proposed protective element provides for higher extent of protection against counterfeit, authenticity of which is at the same time easy to verify.

31 cl, 6 dwg

Description

The present invention relates to a security element comprising a transparent backing material having on the first side a first periodic or almost periodic printed pattern of dots or lines, and on the second side being essentially a mirror image of a second periodic or almost periodic printed pattern of dots or lines having at least one subregion in which the dots or lines are offset with respect to the dots or lines of the rest of the second printing pattern of dots or lines. The present invention also relates to a method for manufacturing such a security element, a data carrier having such a security element, and to the use of such a security element or data carrier to protect an article.

To protect against reproduction, in particular by means of color copiers or other methods, data carriers, for example banknotes, securities, credit or identification cards, passports, certificates, etc., labels, packaging or other means of protecting products are provided with protective elements containing transparent base material, printed on both sides. At the same time, protection against falsification of such a protective element is based on the fact that, in addition to printed images on both sides of the base material, another image can also be visually perceived, which when observed in transmitted light is the result of a superposition of printed images of the front and back sides. An image perceived when observed in transmitted light cannot be made, or can only be insufficiently performed by the above reproducing devices, which makes it easy to distinguish a fake.

For example, from DE 3208204 A1, a printing method for protecting against unauthorized reproduction of banknotes and other documents is known, in which a periodic or almost periodic dot or linear pattern is printed on the front and back sides, for example of a banknote containing translucent paper or other base material. According to the method disclosed in this publication, in any subdomains on the front and back sides, the dotted or linear patterns are deliberately shifted, and moire images are formed that are perceived by the naked eye in transmitted light and used as an identification feature. Although documents produced according to this method provide some protection against reproduction, the disadvantage is that the identification feature is perceived only visually. In addition, it may be relatively difficult for a lay person to distinguish a genuine moire pattern from a moire pattern observed on a fake banknote or similar valuable document.

Thus, the aim of the present invention is to provide a security element of the above type, free from the disadvantages inherent in the known security elements, providing an increased degree of protection against counterfeiting, the authenticity of which, at the same time, is easy to verify. Furthermore, it is an object of the present invention to provide a data carrier with such a security element and a method for manufacturing such a security element.

This problem is solved due to the features disclosed in the independent claims. Embodiments of the present invention are subject to dependent claims.

In the security element according to the present invention, the first printed pattern of dots or lines is combined with a relief pattern made by metallographic printing. In the future, “relief pattern” should be understood as any pattern that contains elevated and deepened sections of the base material and can be made using relief stamps commonly used in metallographic printing. Relief stamps are plates on which deep engraving is performed in various ways.

In addition, in the security element according to the present invention, the first periodic or almost periodic printed pattern of dots or lines interacts with the second printed pattern of dots or lines so that at least one subdomain when viewed in transmitted light has visually perceptible information indicating authenticity of the security element. In the future, a periodic printing pattern of dots or lines should be understood as any pattern whose periodicity satisfies the definition given in the 25th edition of the "Mathematical Handbook" by Bronstein, Semendyaev. Accordingly, dots or lines forming a printed pattern of dots or lines are arranged regularly, i.e. patterns have a repeating interval relative to the distance between points or lines.

In the future, an almost periodic printed pattern of dots or lines should be understood as any pattern that is not exactly periodic, but rather close to it. In particular, “guilloche” can be considered as almost periodic patterns, i.e. patterns of thin geometric lines or ornaments used to print banknotes.

In addition, it should be noted that, within the limits of visual resolution, depending on the size and location of the points, the dot matrix may also appear to the observer as a linear lattice. However, for the purposes of the present invention, the strict difference between the point and linear gratings is not significant, and for this reason this difference is omitted.

In conclusion, it should be noted that the perception of the image of the first and second printed pattern of dots or lines always refers to observation in reflected light, i.e. during reflection, unless it is expressly stated that this visual image of a printed pattern of dots or lines is observed "in the light", i.e. in transmitted light.

Due to the combination of the first printed pattern of dots or lines with a relief pattern, the security element according to the present invention exhibits identification signs that are perceived not only visually, but also tactilely. Therefore, the security element has a so-called “human-perceived sign”, which can be perceived visually and by touch, and which allows a layman to easily verify authenticity. In addition, due to the combination of identification features, which are perceived by touch and visually, the protection against counterfeiting is further enhanced, since the relief patterns of the security element cannot, in principle, be obtained by conventional means of reproduction, for example, by means of color copiers.

The relief pattern made on the first side of the base material, to some extent also always forms a negative relief pattern on the second side of the base material, as a result of which the protective element is tactilely perceived on both sides. Thus, the degree of protection against counterfeiting is further enhanced, and the security element on both sides gives the user a sensation characteristic of a valuable document.

In addition, it is preferable that due to the interaction of the first and second printing pattern of dots or lines in at least one subregion, when viewed in transmitted light, an information element is perceived, which indicates the presence of authenticity. In the future, under the "element of information perceived in transmitted light", we should understand any information that, without auxiliary means, indicates to the observer the authenticity of the protective element. The easily perceptible additional element of information of the security element further enhances protection against counterfeiting, since it cannot be reproduced by means of reproduction, such as scanners or color copiers, or can only be reproduced insufficiently.

According to a preferred embodiment, the first printing pattern of dots or lines is a printing layer made by metallographic printing. Thus, the base material preferably has at the same time a first printing pattern of dots or lines and a relief pattern according to the present invention, since the metallographic printing method allows, in addition to performing the relief pattern, to simultaneously apply printing ink. Such printing is also called "colorful metallographic printing." Due to the simultaneous application or placement during metallographic printing of the first printing pattern of dots or lines or a relief pattern, the first side of the security element according to the present invention can be performed in one step of the method, which, as proved, saves time and money.

In addition, it is especially advisable if the printed layer is applied, essentially, congruently raised areas of the relief pattern. However, even with properly executed recesses in the metallographic printing plate and proper erasure of the printing ink in the recesses before printing, it cannot be ruled out that the printing ink will not be applied congruently to the raised portions of the relief pattern, with the congruence of the printing layer and the relief pattern being particularly preferred, since in this way it is possible to realize the exact combination of a point or linear pattern and a relief pattern. The ink relief obtained by colorful metallographic printing is very well perceived by the user by touch and visually.

In addition, it may be appropriate if the first printing pattern of dots or lines is a printing layer made by offset or screen printing, flexography, xerography, inkjet printing, thermal printing or a laser printer. Each of the above printed layers exhibits, depending on the method of implementation, certain properties that are sufficiently known to a person skilled in the art. Thus, the choice of a particular printing layer will depend on the printing ink used, the required resolution, the printed image, etc. In a printed pattern of dots or lines made in accordance with this embodiment of the invention, the printing and embossing processes on the same side of the base material are separated. Thus, despite the fact that it is required to perform printing and relief in two stages, at the same time, the division into two stages provides greater freedom of design of the parameters of the printed pattern. Thus, it is possible to make, for example, printing patterns from lines with a linear raster different from the relief pattern, which cannot be done in the same way with metallographic printing, or it can only be done to a very limited extent. In any case, in one step of the method, using a metallographic printing plate not filled with printing ink, the so-called "colorless embossing" is performed, which allows combining the relief pattern according to the present invention with the first printing pattern of dots or lines.

When performing, through the above separate operations, a first printing pattern of dots or lines and a relief pattern, it is particularly preferable if, for forming a pattern with variable optical properties, the first printing pattern of dots or lines and the relief pattern are arranged so that at least part of the first printing pattern patterns of dots or lines are completely visible when observed along the normal, but are hidden when observed at an angle. A pattern with variable optical properties, made in this way, demonstrates the visually perceived effect of changing properties when tilted, which in itself is an identification sign.

To perform such a pattern with variable optical properties, it is necessary that the relief lattice and the printed pattern have a certain spatial arrangement relative to each other, in which the raised portions of the relief pattern, when viewed at an angle, cover at least parts of the printed pattern. In particular, the pronounced effect of a change in properties upon tilting requires that the printed layer in at least one region does not coincide with the raised portions of the relief pattern and, since otherwise, there will be no effect depending on the angle of inclination or only a minimal effect will occur.

In addition, it is advisable that the first printed pattern of points or lines and / or the second printed pattern of points or lines be a linear lattice with a constant linear raster. A printed pattern with a constant linear raster is a special case of a periodic printing pattern, provided, however, that it has only a certain period that does not change within the printing pattern. The printed pattern with a constant linear raster can be made relatively accurately by known printing technologies and, in addition, goes well with a graphic motif or geometric pattern, potentially located additionally on the corresponding side of the security element.

It should be noted that, in the case of an identical linear raster of printed patterns on the first and second side of the security element, the location of the printed patterns with perfect alignment is not necessary. Sometimes when observing in transmitted light, at least on a part of at least one subregion, interesting ripple effects can occur that arise as a result of the location of the first and second printed patterns with imperfect alignment.

The relief pattern of the security element may preferably be a linear grid with a constant linear raster. Such a relief pattern can be accurately made using metallographic printing technology and can be combined, particularly preferably, with a printed pattern of dots or lines of an identical linear raster made in the form of a linear lattice. If the printed pattern and the relief pattern are made at one step of the method, as described above, and each recess on the metallographic printing plate is filled with printing ink, then, according to this embodiment of the method, it is easy to combine a printing pattern and a relief pattern with an identical linear raster. If the printed pattern and embossing were performed in the course of separate operations, as was also described above, then for printing and embossing the linear raster should be the same.

In addition, it is advisable that the relief pattern of the first side forms, on the second side of the data medium, a substantially negative relief pattern that, in order to form a pattern with variable optical properties, interacts with a second printing pattern of dots or lines in such a way that at least parts of the second printed pattern of dots or lines are completely visible when observed along the normal, but are hidden when observed at an angle. As already mentioned, due to the presence of a relief pattern on the first side, and on the second side, a negative relief pattern is also always present to some extent. If the protrusions and recesses on the second side are sufficiently high or deep and combined with the corresponding printing pattern, then as a result, a pattern with variable optical properties is always formed on the second side. This pattern can also be combined with a pattern with variable optical properties on the first side of the base material. Such a security element having a pattern with variable optical properties on both sides of the base has exceptional counterfeit protection and provides the touch element with a high degree of perception.

In another preferred embodiment of the invention, the points or lines of at least one subregion are offset by a fraction of the linear raster of the linear array relative to the points or lines of the rest of the second printed pattern of points or lines. Particularly preferred is an offset of one third of the linear raster of the linear lattice. In this way, a subregion is obtained with a relatively clearly defined offset relative to the rest of the printing pattern.

In addition, it is particularly preferable if the second printed pattern of dots or lines contains several subregions. Thus, it is possible with a high degree of reliability to create an information element that is perceived when observed in transmitted light and indicates the authenticity of the protective element, which remains visible even after the partial destruction of the protective element.

In addition, it is advisable if the printed pattern of dots or lines containing several subregions forms a second information element containing m subregions in the horizontal direction and n subregions in the vertical direction, and the ratio m, n≥1, preferably m, n ≥2. In addition to the structure in the form of a matrix having one column and several rows, a structure in the form of a chessboard is also preferable, with m = n. In this embodiment of the invention, the degree of protection of the security element against counterfeiting is increased since, even with the destruction of part of the subdomains, in the surviving subdomains the information elements observed "in the light" remain visible. On the other hand, the security element can be made technically sophisticated and thus protected against counterfeiting due to its inherent properties.

In another preferred embodiment of the security element, the points or lines of the subdomains are offset by different parts of the linear raster of the linear array relative to the points or lines of the rest of the second printed pattern of points or lines. Due to the different displacements of points or lines in different sub-regions when observed in transmitted light, the sub-regions have different brightness due to the fact that the dots or lines of the first and second printing patterns overlap to varying degrees. Thus, an information element indicating authenticity can be perceived in different subdomains with different brightness, which is very attractive to the observer.

It should be noted that, in addition to displacing dots or lines in at least one fragmented area, an information element indicating authenticity can also be obtained by modulating the width of the lines in the subregions of the second linear printing pattern. This type of coding through line modulation is known per se to those skilled in the art and can be used for a security element according to the present invention. However, the perception of the corresponding information observed in the light is worse than in the embodiments described above.

According to another embodiment, the second printing pattern of dots or lines is a printing layer made by metallographic printing, offset printing, screen printing, flexography, xerography, inkjet printing, thermographic printing or a laser printer. As already mentioned, the printed pattern, depending on the method of its implementation, exhibits certain properties, known per se to specialists in this field of technology. If not only the second printed pattern from dots or lines, but also the first pattern is also made by metallographic printing, then the received security element has a combined printed-relief pattern on both sides. In this case, the thickness of the layer of the base material and the parameters of embossed embossing, of course, must be selected so that there is no mutual destruction of the relief pattern of one side by the relief pattern of the other side. In addition, it may well be necessary to further strengthen the negative relief pattern, made on the one hand and, to some extent, available on the opposite side, by placing the second relief pattern on the opposite side.

In addition, it is preferable if part of the first printing pattern of dots or lines and / or the second printing pattern of dots or lines is made by laser radiation. Moreover, CO ₂ lasers, Nd: YAG lasers or other types of lasers in the wavelength range from ultraviolet (UV) to far infrared (IR), as well as often lasers operating with frequency doubling, tripling, can be used as a radiation source frequency or even with a greater frequency increase frequency. However, it is preferable to use laser sources near infrared (IR), since this wavelength range is well consistent with the absorbing properties of substances provided for printing patterns. Since, depending on the application, the size of the laser spot can vary from a few microns to several millimeters, the printing patterns according to the present invention can preferably be made using laser radiation. The continuous output of the laser used for this purpose is usually from a few watts to several hundred watts.

If the base material used absorbs laser radiation of a selected wavelength range, or the base material contains an additive that absorbs this radiation, then part of the printed pattern of dots or lines can be made by bleaching the base material. However, it is preferable to produce dot or linear gratings on a printed image previously applied by one of the printing methods. In this case, due to the action of laser radiation, a part of the pre-printed layer is destroyed, and a fine-structured dot or linear lattice is formed.

To further increase the degree of protection against counterfeiting according to another preferred embodiment, the first and / or second printed pattern of dots or lines is at least partially a multicolor layer. Thus, in addition to the different color images of the first and second printed patterns in transmitted light, interesting color mixing effects can be obtained, which also increase the reproduction protection.

In addition, the first and / or second printing pattern of dots or lines may be a printing ink with variable optical properties or a printing ink with a metallic effect. In this case, preferably, printing inks with a gold or silver effect can be used as a printing ink with a metallic effect. As a printing ink with variable optical properties, printing inks containing interference layer pigments or liquid crystal pigments are preferably used. These inks with varying optical properties create a certain color for the observer, depending on the viewing angle. In addition, when using these printing inks, anti-fake protection is further enhanced.

In addition, it may be appropriate if the first and / or second printed pattern of dots or lines exhibit machine-readable properties in at least some areas, since such a security element, in addition to the so-called “human-perceived signs”, also has identification signs that can be checked at an additional level of protection. For example, banks and similar institutions may be interested in such verification.

According to a further embodiment, the security element may have additional layers and identification features, such as an additional translucent layer, a layer with variable optical properties or a film element. In this case, an additional translucent layer can be applied, preferably, to an already printed printed pattern of dots or lines with a colorful stamp. However, it is also possible to apply both a printed pattern and an additional transparent layer with variable optical properties to the printed pattern at certain stages, for example, offset printing or printing using the Nyloprint technology. If you observe the printed pattern from above, then due to the use of a translucent layer with variable optical properties, the printing ink of the printed pattern changes depending on the direction of observation. In this case, a pronounced effect of a color change upon tilt is manifested, mainly with dark colors of the printing pattern, such as black or dark green. However, at the same time, due to the transparency of the additional layer with variable optical properties, the perception of information "in the light" is in no way reduced. The security element according to this embodiment is relatively difficult to manufacture, but at the same time very well protected from counterfeiting.

The above additional layers and elements may be superimposed on the first and / or second printed pattern or lie below the first and / or second printed pattern.

An element of visually perceptible information when observed in transmitted light in at least one subregion is preferably an alphanumeric character, symbol and / or geometric pattern. The alphanumeric character may be, for example, the face value of a data carrier, for example, a banknote containing this security element. Particularly protected from counterfeiting and at the same time very complex, is an individualized security element, which when viewed in transmitted light allows you to perceive an element of individualizing information that indicates authenticity. Letters of all known fonts can be used for alphanumeric characters, although it is particularly preferable to use letters relating to the main Latin (Basic Latin) and the main Greek (Basic Greek) fonts. A symbol can be a cross or a double cross, a figure bounded by a polygon, or, for example, a circle. Geometric patterns can be, for example, a guilloche pattern or a snowflake-shaped outline.

It is clear that the visually perceptible information element is different in different subdomains, or that the individual information elements of the subdomains complement each other to form an aggregate information element, for example, a numerical value of a nominal.

In principle, any transparent backing material can be used for the security element. In this case, the transmittance must be at least so high that the information element located in at least one subregion is visually perceptible in transmitted light. To improve the perception of information by the observer, you can use additional illumination, even if the thickness of the material is chosen such that the perception of signs in transmitted light is also possible without auxiliary means. In addition, the used base material must have properties that allow the relief pattern according to the present invention to be performed by metallographic printing.

Thus, paper, especially cotton and velvet, is preferred as the base material. Of course, paper can also be used containing a mass fraction x of polymer 20 material of 0 <x <100%.

In addition, the base material is preferably a plastic film. As the film material, in particular, PET (polyethylene terephthalate), PBT (polybutylene terephthalate), PEN (polyethylene naphlate), PP (polypropylene), PA (polyamide) and PE (polyethylene) can be used. In addition, the film can be stretched along one or along two axes. Stretching the film gives it, among other signs, properties that can be used as additional signs of protection. In order to take advantage of these properties, auxiliary means, such as polarizing filters, are known to those skilled in the art.

It may also be appropriate if the base material is a multilayer composite that has at least one layer consisting of paper or paper-like material. Such a composite is characterized by extremely high stability, which is a great advantage for the durability of security features and, in addition, increases the degree of protection against counterfeiting.

But as the base material, it is also possible to use a multilayer, paper-free composite material. These materials can also be used preferably in certain climatic regions of the Earth.

All materials used as the base material may contain additives that serve as identification features. In this case, luminescent substances can advantageously be provided, which in the visible wavelength range are preferably transparent, and in the invisible wavelength range, in order to induce visible or at least detectable luminescence, they can be excited by appropriate means, for example by source of ultraviolet (UV) or infrared (IR) radiation. Preferably, other security features can also be used provided that they do not or only slightly affect the visual perception of the printed patterns when viewed from above or an information element in transmitted light.

The security element of the present invention may be applied to a storage medium such as secured and valuable documents, for example banknotes, stocks, bonds, certificates, vouchers, bank and identification cards, passports or the like. Thus, the storage medium contains a security element which, even to a non-specialist, is easily recognizable to increase counterfeit protection. The security element of the present invention is also very preferably used in the field of product protection. In this case, the protective element can be applied on the appropriate labels, on the packaging or on the product itself.

Also particularly preferred is a data carrier comprising a watermark and a security element located at least partially in the region of the watermark. Thus, in a preferred embodiment, the known identity is combined with the identity of the present invention, and the degree of protection against counterfeiting is further enhanced.

For the manufacture of the security element according to the present invention, it is preferable to first apply a first and second printed pattern of dots or lines to a transparent base, and then, in accordance with the exact register, a relief pattern is made. In principle, however, it is also possible to carry out the steps of the method in the reverse order. The printing layer can be performed by any printing method, such as flat printing, for example, offset printing; relief printing, for example, letterpress, or flexographic printing; screen printing, intaglio printing, for example, raster intaglio printing or metallographic printing, or by thermographic method. In addition, the coating can also preferably be performed on a laser printer or by exposure to laser radiation.

The relief pattern is performed using a metallographic printing plate as a stamp for embossing. For this, embossing is carried out like a bezelless embossing by means of an ink-free printing plate. However, according to a particular embodiment of the invention, the embossed pattern can also be made by means of colorful metallographic printing. This manufacturing option, in particular, can be used for implementations in which the printed pattern is performed congruently with the embossed pattern.

To make a stamp for embossing, the surface of the plate is cut out, for example, by means of an engraving cutter or a laser. Any material can be used on the surface of the plate, for example copper, bronze, steel, nickel or the like. The engraving tool used for cutting preferably has an apex angle of about 40 ° and a rounded tip close to the shape of a spherical segment or sector. In this case, the stamp for embossing can be cut only in one copy or in multiple copies.

In principle, the sequence of steps of the printing and embossing method can be freely selected. Typically, a coating is first applied and then embossed. Thus, the height of the relief and the shape of the embossing are free from the subsequent influence that occurs, for example, during the subsequent printing operation. However, an alternative, when embossing is first performed and then coated, has the advantage of providing higher color brightness and a more clearly defined print. This effect is based on the fact that during embossing, the base is simultaneously calendared and therefore a smoother, less absorbent surface is obtained.

It should be noted that specifically for two-sided printing, a printing plate can be used having a recess in the area of the first printing pattern, accommodating at least a subregion of the first printing pattern to protect it from the effects of printing of the second printing pattern. Through the use of such a special printing plate, the relief height and the shape of the first printing pattern or embossing on the first side are protected from the effects of printing on the second side, especially from adversely affecting calendaring.

In connection with the mention of a specially made printing plate for protecting the first printing pattern or embossing on the first side, the corresponding method and the security element and data carrier made with it, we will refer to the pending German patent application with the number DE 10 2006036670.0, the contents of which in this regard, is included in the content of this application.

The advantages of the present invention will now be explained with reference to the following implementation examples and the accompanying drawings. The individual features and implementation examples described below have the features of the invention individually and in combination. Examples are preferred embodiments of which, however, the present invention cannot be limited in any way. The proportions shown in the drawings do not correspond to real ratios and serve solely to facilitate understanding.

The drawings show:

figure 1 - the front side of the data carrier with the first side of the protective element according to the present invention, when viewed from above,

figure 2 is the back side of the data carrier according to figure 1 with the second side of the protective element according to the present invention, when viewed from above,

figure 3 - the front side of the data carrier according to figure 1, containing a protective element according to the present invention, when observed in transmitted light,

figure 4 is a second side of the inventive security element according to figure 2, an enlarged top view,

figure 5 is a section along the line aa in figure 1,

figure 6 is a section along the line aa in figure 1 for another security element according to the present invention,

Figure 1 shows a data carrier 10 according to the present invention in the form of a banknote having a security element 3 located in the printed image area of the data carrier 10. According to the present invention, the security element 3 is used as the so-called "human-perceived sign", i.e. as a sign that can be checked by a person without auxiliary means, in addition to other, if necessary, other authenticity signs, such as security threads, watermarks, etc. The presence of such features is especially preferred on banknotes, but also on other valuable documents such as stocks, checks and the like. In the context of the present invention, labels, passports or cards that are currently used, for example, to identify individuals or goods, or to carry out other operations or services, can also be considered as storage media.

All the security elements according to the present invention have the common property that they themselves and the realized effects cannot be imitated by the currently known reproduction technologies, especially copying devices, since these devices can only reproduce the corresponding side of the security element, including form, as it is visible from above, as a result of which the effect is lost when observing "in the light". In addition, playback will also be generally unsuccessful due to the too low resolution of the reproducing apparatus. And, finally, by the nature of the reproduction technologies, no relief patterns can be made, which also increases the degree of protection against counterfeiting.

Next, examples of two preferred embodiments of the present invention will be explained with reference to the drawings. In order to facilitate understanding, the images in the drawings are rather schematic and do not display all the details.

For a better understanding, the embodiments described below are reduced to information containing the essence of the invention. In practice, in single-color or multi-color printing, essentially more complex printing patterns can be used as the first or second printing pattern of dots or lines. The same applies to the embossed pattern. The relief pattern typically has an embossing height in the range from 10 μm to 250 μm, preferably from 50 μm to 120 μm. The disclosed implementation examples also do not have to be applied exactly as disclosed in the application, but can also be combined with each other to enhance effects.

In addition, in order to be able to graphically represent the optical effects of the security element according to the present invention, only the embodiment and the relative position of the first and second printing patterns or the relief pattern are presented below.

As shown in FIG. 1, the security element 3 has a first printed pattern on the first side of the base material, which in this case is a cotton and velvet banknote paper. The printed pattern is a periodic linear printed pattern with a constant linear raster. In this case, the linear raster is selected so that it is optically mixed with the pattern of the surrounding guilloche pattern 11. The printing of the linear printing pattern 1 and the guilloche 11 from the front side of the banknote 12 is carried out using a colorful metallographic printing method.

According to figure 2, the linear printing pattern 2, made essentially as a mirror image of the printing pattern of the front side, is located on the reverse side 13 of the banknote 10, and therefore on the second side of the security element 3. On the reverse side, the linear printing pattern 2 has a linear a grid with an identical linear raster and essentially mirrored lines of the front side of the linear print pattern 1. Only the width of the lines of the pattern 2 is slightly larger than the width of the lines of the pattern 1, so that the print-free sections of the pattern 2 occupy an area l smaller than for pattern 1.

Figure 3 presents the front side 12 of the banknote 10, when observed in transmitted light. Obviously, in transmitted light, the first and second linear printing patterns 1 and 2 overlap in such a way that an information element 7 is displayed that displays the face value of a banknote, namely, “500”. In a real situation, the information element 7 is recognizable in two other subdomains of the security element 3 (namely, above and below the information element 7), but with a different contrast, which cannot be adequately displayed using the reproduction technology applied to FIG. 3.

Further details of the security element according to the present invention are described with reference to FIGS. 4-6.

As already mentioned, the linear printing pattern 2 is made essentially as a mirror image of the linear printing pattern 1 of the front side. In addition, it has subregions in which the lines are offset from the surrounding lines. According to figure 4, sections 4a, 4b and 4c contain a pattern with the same linear pattern as that of the printing pattern 1, printed as a mirror image from the back side 13 of the banknote 11.

In addition, the linear printing pattern 2 has regions in which the lines are offset with respect to the lines of the remaining regions of the printing pattern 2, namely, regions 4a, 4b and 4c. Such regions are, for example, regions 5a, 5b and 5c, as well as 6a, 6b and 6c. In this case, in this case, the areas 5a-5c interact with the corresponding areas 6a-6c so that an information element is encoded in them. In the presented implementation example, this is the face value of "500". When observing the printed pattern 4 from above, the encoded information is very difficult to perceive visually. However, when viewed in transmitted light, thanks to the protective element 3 according to the claimed invention, the information element is perceived easily and clearly. In addition to the information “500” visible “by the light” when observing the linear print pattern 1 shown in FIG. 3, a mirror image of the information “500” when viewing the linear print pattern 2 in transmitted light is also perceived. This, respectively, applies to subdomains 5a, 6a and 5c, 6c and the information element perceived in these subregions when observed in transmitted light.

The line offset at which an information element is encoded in the subregions 5a-5c and 6a-6c of the printing pattern 2 is shown in more detail in FIG. The base material 30 has a relief pattern made by the method of metallographic printing and having raised sections 31 and grooves 32. The relief pattern is made in the form of a linear lattice having a linear raster R1. The first linear printing pattern 1 is applied to the base material 30 by means of colorful metallographic printing simultaneously with a relief pattern. Figure 5 shows in cross section three lines 1a, 1b, and 1c located substantially congruently to the raised sections 31 of the embossing grate.

The second linear printing pattern 2, deposited by offset printing, is made on the back side of the base material 30. It is a 20 linear lattice with a linear raster R2, wherein the lines 2a, 2b, 2c and 2d of this lattice are shown in cross section in FIG. In the presented case, the linear rasters R1 and R2 of the lattice of the front side and the reverse side coincide.

When observing the linear printing pattern 1, a linear pattern is perceived from above, which, due to the use of dark printing ink, stands out against the background of light, free from printing areas of the base material 30. Therefore, when viewed from above, the linear printing pattern 2 can also be perceived as a sequence of lines 2a-2d made in a dark tone, and sections of the base material 30 free from the printing layer contrast with them.

As also shown in FIG. 5, line 2c is offset with respect to adjacent lines 2b and 2d. The offset is indicated by position number R21. The periodically repeating interval 40 of the lines of the linear printing pattern 2 along the surface of the substrate is reduced as a result of its 5 reduction to the interval 41 or increases to the interval 42, respectively, which is clearly visible in the sections of the line 2C.

When observed in transmitted light, due to the combined action of the linear printing patterns 1 and 2, the sequence of dark printed areas and light, free from printing, sections of the base material 30 can be perceived from the front side 12 of the banknote 10 or the security element 3. Therefore, when observed in transmitted light, as a result, a regular light / dark contrast is obtained on the sections of the linear gratings 1 and 2 of the front side and the back side, respectively, in which the lines do not overlap. In this case, when viewed in transmitted light in direction A1, a portion S0 that does not have a print layer on the front and back sides of the protective element 3 appears in transmitted light as a region of bright color, in accordance with the printing ink of the base material 30. On the other hand, when the line 2c is shifted, a larger section S1 free from the printing layer is formed, located between lines 1b and 1c and visible to the observer of the linear array 1 when viewed in transmitted light in direction A1. In transmitted light in the A1 direction, the section between lines 1b and 1c looks brighter than the section between lines 1a and 1b due to the larger section S1 that is free of the printed layer. The above explanations relate similarly to the observation in transmitted light of lines 2a, 2b and 2b, 2c of a linear printing pattern 2 in the direction A2.

For example, the offset of line 2c shows how, by offsetting the plurality of lines of the linear printing pattern 2, an information element encoded and essentially invisible when the security element 3 is viewed from above becomes visible in transmitted light.

In addition, figure 5 shows that the introduction of embossed patterns into the base material 30 forms a negative embossed pattern on the second side that interacts with the second linear printing pattern 2 in such a way that a pattern with variable optical properties is obtained. While when observing from above in the direction of A2, the observer can see a sequence of lines and areas free of the printed layer, when observing in direction B2, the lines of the linear array 2 are partially hidden or shaded, as a result of which the tone changes compared to the observation in direction A2, becoming lighter. Therefore, in the direction C2, at least a portion of the print-free sections 40, 41 is hidden by the raised sections 33 of the base material 30, so that the visual image in the observation direction C2 is different from the visual images perceived by the observer in the directions A2 and B2, becoming more dark. This effect of changing optical properties when tilted is quite pronounced on the back side 13 of the banknote 10, while it is almost barely noticeable when observing the linear printing pattern 1 on the front side 12 of the banknote 10, due to the essentially congruent arrangement of the linear grating 1 and the raised sections 31 relief patterns. As a result, essentially the same optical image is formed in the viewing directions A1, B1 and C1 of the printing pattern 1 for the observer.

Figure 6 shows a cross section of another security element 3 according to the claimed invention, where the linear printing patterns 1 and 2 are located on the first and second side of the base material 30. While the linear printing pattern 2 essentially corresponds to the linear printing pattern 2 of the embodiment of FIG. 5, the linear printing pattern 1 is significantly different from the linear printing pattern 1 shown in FIG. 5. In contrast to the colorful metallographic printing of the embodiment shown in FIG. 5, the printed pattern 1 of the security element in FIG. 6 was offset offset printed and combined with a relief pattern made by the metallographic printing method in a separate step of the method. Thus, it is possible to arrange each line 1a, 1b and 1c of the linear array 1 on one side of the embossed pattern, while the vertices 31 remain unsealed. If the linear rasters R1 and R2 of the two linear gratings 1, 2 are selected of the same size, then essentially the same effects appear in transmitted light, which are disclosed in the description of the embodiment in Fig. 5, but with different intervals of light and dark areas. The latter follows directly from the exact location of lines 1a, 1b, 1c and 2a, 2b, 2c on the base material 30.

On the other hand, the effect of the variable optical properties of the linear printing pattern 1 is also not visible from the front side of the security element 3, since the visual image is different in the viewing directions A1, B1 and C1. Similar to the already described effects of changes in properties when tilted for the reverse side, in the A1 direction, as a result, on the front side of the linear pattern 1, an alternation of light, non-printing, and dark, printed parts of the base material 30 also occurs. In the direction B1, the linear pattern seems darker, and in the direction C1, on the contrary, it is lighter. Therefore, as a result, when observing the security element 3 in FIG. 6, a variable optical effect of the printed patterns 1 and 2 of the first and second sides appears from above. In addition, in transmitted light, due to the displacement of the line 2c, an additional information element 7 is visible, indicating the authenticity of the protective element 3, as already described previously for FIG.

In addition, the depicted relief pattern of the second side of the base material 30 can be enhanced if the so-called “colorless embossing” is added when printing the linear pattern 2 in the metallographic printing method.

In addition, the reverse side or the front side of the linear printing pattern 2 or 1, respectively, may contain an additional translucent layer with variable optical properties from above or below, through which, depending on the direction of observation, in each case, additional effects of color change when tilted to the corresponding side appear . For ease of understanding, such an additional layer is not shown in the drawings.

Claims (31)

1. A security element comprising a transparent base material, which on the first side has a first periodic or almost periodic printed pattern of dots or lines, and on the second side has a second periodic or almost periodic printed pattern of dots which is essentially a mirror image thereof, or lines containing at least one subregion in which the dots or lines are offset relative to the dots or lines of the rest of the second printed pattern of dots or lines, characterized in that the first printed pattern of dots and whether the lines are combined with a relief pattern made by metallographic printing, and that the first printed pattern of dots or lines interacts with the second printed pattern of dots or lines so that at least one subdomain contains an information element that is perceptible when observed in transmitted light, indicating the authenticity of the security element. 2. The security element according to claim 1, characterized in that the first printed pattern of dots or lines is a printed layer made by metallographic printing. 3. The security element according to claim 2, characterized in that the printing layer is located essentially congruent to the raised portions of the relief pattern. 4. The security element according to claim 1, characterized in that the first printing pattern of dots or lines is a printing layer made by offset printing, screen printing, flexography, xerography, inkjet printing, thermal printing or by means of a laser printer. 5. The security element according to claim 4, characterized in that for creating a pattern with variable optical properties, the first printed pattern of dots or lines and the relief pattern are arranged so that at least parts of the first printed pattern of dots or lines are completely visible when observing along the normal, but hidden when observing at an angle. 6. The security element according to claim 5, characterized in that the first printed pattern of dots or lines and / or the second printed pattern of dots or lines are a linear lattice with a constant linear raster. 7. The protective element according to claim 1, characterized in that the embossed pattern is a linear lattice with a constant linear raster. 8. The security element according to claim 7, characterized in that the linear lattice of the first printed pattern of dots or lines and the linear lattice of the relief pattern have the same linear raster. 9. The security element according to claim 1, characterized in that the relief pattern of the first side on the second side forms an essentially negative relief pattern, which interacts with the second print pattern of dots or lines to form a pattern with variable optical properties so that at least portions of the second printing pattern of dots or lines are fully visible when observed along the normal, but are hidden when observed at an angle. 10. The security element according to claim 6, characterized in that the points or lines of at least one fragmented area are offset by a fraction, in particular by one third, of the linear raster of the linear array relative to the points or lines of the rest of the second printed pattern of dots or lines. 11. The security element according to claim 1, characterized in that the second printed pattern of dots or lines has several subregions. 12. The security element according to claim 11, characterized in that the subregions form a two-dimensional matrix having in the horizontal direction, m subregions, and in the vertical direction, n subregions, and the ratio m, n≥1, preferably m, n≥2, is fulfilled. 13. The security element according to claim 11, characterized in that the points or lines of the subregions are offset by different parts of the linear raster of the linear lattice relative to the points or lines of the rest of the second printed pattern of the points or lines. 14. The security element according to claim 1, characterized in that the second printing pattern of dots or lines is a printing layer made by the method of metallographic printing, offset printing, screen printing, flexographic printing, xerography, inkjet printing, thermal printing or by means of a laser printer. 15. The security element according to claim 1, characterized in that a part of the first printing pattern of dots or lines and / or the second printing pattern of dots or lines is made by means of laser radiation. 16. The security element according to claim 1, characterized in that the first printed pattern of dots or lines and / or the second printed pattern of dots or lines is part of a graphic motif or geometric pattern located on the first or second side, respectively. 17. The security element according to claim 1, characterized in that the first printed pattern of dots or lines and / or the second printed pattern of dots or lines is at least partially a multicolor layer. 18. A security element according to any one of claims 1 to 17, characterized in that the first printing pattern of dots or lines and / or the second printing pattern of dots or lines is a printing ink with variable optical properties or a printing ink with a metallic effect. 19. The security element according to claim 1, characterized in that the first printed pattern of dots or lines and / or the second printed pattern of dots or lines has machine-readable properties in at least some areas. 20. The protective element according to claim 1, characterized in that at least one side of the protective element has an additional translucent with variable optical properties layer or film element. 21. The security element according to claim 1, characterized in that the element of visually perceived information observed in transmitted light in at least one fragmented area is an alphanumeric character, symbol and / or geometric pattern. 22. The security element according to claim 1, characterized in that the base material is paper, in particular cotton and velvet paper. 23. The protective element according to claim 1, characterized in that the base material is a plastic film, in particular a film containing PET (polyethylene terephthalate), PBT (polybutylene terephthalate), PEN (polyethylene naphlate), PP (polypropylene), PA (polyamide) or PE (polyethylene). 24. The security element according to claim 1, characterized in that the base material is a multilayer composite having at least one layer containing paper or paper-like material. 25. A storage medium containing a security element according to any one of claims 1 to 24. 26. The storage medium according to claim 25, wherein the storage medium is a security, in particular a banknote. 27. The storage medium according to p, characterized in that the storage medium has a watermark, and the security element is located at least partially in the area of the watermark. 28. The use of a protective element according to any one of claims 1 to 24 or a data carrier according to any one of claims 25 to 27 for protecting products. 29. A method of manufacturing a protective element containing a transparent base material, on the first side of which a first periodic or almost periodic printed pattern of dots or lines is printed, and on the second side is printed, which is essentially a mirror image of a second periodic or almost periodic printed pattern of dots or lines, containing at least one subregion in which the dots or lines are offset with respect to the dots or lines of the rest of the second printing pattern of dots or lines from characterized in that a metallographic printing method performs and combines with the first printing pattern of dots or lines a relief pattern, wherein the first printing pattern of dots or lines interacts with the second printing pattern of dots or lines in such a way that at least one fragmented portion contains an element of visually perceptible information observed in transmitted light, indicating the authenticity of the security element. 30. The method according to clause 29, wherein the first printed pattern of dots or lines and / or the second printed pattern of dots or lines is performed by flat printing, such as offset; embossed printing, for example letterpress or flexographic; screen printing; intaglio printing, for example deep raster or metallographic; by inkjet or thermographic method, for example by thermal transfer or laser printing. 31. The method according to clause 29 or 30, characterized in that a part of the first printing pattern of dots or lines and / or the second printing pattern of dots or lines is performed by means of laser radiation.

Images