EP2608161A1 - Verification of security documents with a window with optically effective microstructures - Google Patents

Abstract

The method involves locating information in a transparent region of a substrate, and displaying other information correlated with the former information by using an active luminous display (1). The substrate is set with the former information over the latter information that is displayed using the display. Hidden information are recognized and/or read. The former information are formed by a raster-like arrangement of optical effective microstructures, where the raster-like arrangement is adapted to a raster-like array of red, green and blue pixels of the display. The display is a picture screen of a computer, a notebook or a laptop, a monitor of a cash register of a point of scale system or a display of a handset unit. Independent claims are also included for the following: (1) a method for verification or checking of a valuable object (2) a device for execution of a method for verification of a valuable document.

Description

The invention relates to a method and a device for verifying documents of value such as banknotes, securities, credit, debit or ID cards, passports, documents, tickets, tickets and the like, labels, packaging, tax stamps, cigarette strips or other elements for product assurance or marketing campaigns. Here, a first information is arranged in at least one transparent area of a security element. A separate display, such as a screen of a computer, notebook or laptop, a monitor of a cash register of a cash register system or a display of a handset, at least partially displays a second information. Either in the first or the second information or also in both information, further information is hidden, which is not or only barely recognizable and / or readable for a viewer without aids. A verification of the security element is carried out by the first information in the translucent area of the security element is placed on the second information and the hidden information is recognizable and / or readable. The invention further relates to a corresponding method for verifying or checking valuables having a display, for example a computer, notebook or laptop, a cash register of a cash register system, television or a hand-held device.

A generic method is off WO 2009/019038 A1 known. In this case, the hidden information advantageously contains, for example, the emission value or the currency of a banknote and can thus serve as an authenticity check at a point-of-sale terminal. The banknote is placed over the display of the point-of-sale terminal and the information hidden on the banknote is displayed in plain text for the cashier. Out WO 2009/019038 A1 It is known that a moiré pattern results when a grid of diffusing elements of dummy embossing or optical lenses is applied to the light-transmissive area of the security element or the verification element and a micro-information matched to the scattering elements is displayed on the display. The micro-information is represented by the superposition of the grid of scattering elements magnified many times, but must be adapted to the grid of the security element or the verification element.

Furthermore, the known from the prior art indirect high pressure in conjunction with the substrate to be printed usually allows for positive lines a minimum line width of 40 microns and negative lines of 80 microns. Here, a positive line is a printed line-shaped area formed by a printing ink, while a negative line is a recessed line-shaped area without printing ink in a full-area or raster-shaped printed area. With offset printing, a minimum line width of 30 μm can be achieved with positive lines and a minimum line width of 50 μm with negative lines. However, it has to be taken into account that in the printing process due to slippage, the rheology of the ink and the capillary forces in the substrate (color fringe, edge to edge), the line width increases, which can amount to approx. 5 μm on each side of the line. This increases the actual line width, for example, to 40 μm for positive lines in offset printing and to 50 μm for indirect high pressure.

The trend is for displays of mobile phones, smart phones, TVs and other devices to extremely high resolutions, ie a particularly high number of pixels per unit area. State of the art are so-called Active matrix displays, in which a liquid crystal screen consists of a matrix of pixels, the so-called display matrix, each individual pixel having an active amplifier and power supply connections. The individual pixels of the display matrix can not be seen by an observer with an unarmed eye, but only by means of a microscope. For example, the so-called retina display of the current smartphone "iphone 4" from Apple has a resolution of 960 × 640 pixels with a screen size of 8.9 cm or the so-called AMOLED display of the smartphone "Galaxy S I9000" from the company Samsung® has a resolution of 480x800 pixels with a screen diagonal of 10.2 cm.

Such a high resolution can not be achieved with the currently known from the prior art printing process or only with high reject rates, at the expense of contrast or loss of image information.

The invention is therefore the object of developing a generic security element such that the disadvantages of the prior art is eliminated and the protection against counterfeiting is further increased.

This object is solved by the features of the independent claims. Further developments of the invention are the subject of the dependent claims.

According to the invention, the first information is formed by a grid-like arrangement of optically active microstructures. With an optically effective microstructure, the necessary resolution is achieved in order to produce a grid which has a high resolution on the display matrix Displays is tuned or can be adapted to even higher resolution future displays.

A microstructure in the sense of this invention is a structure having a lateral dimension, i. whose length and / or width, in the micrometer range. Preferably, the length and / or width is less than 50 microns, and more preferably less than 30 microns.

According to the invention, the grid-like arrangement of optically effective microstructures is adapted to the grid-like arrangement of pixels of the display.

For the purposes of this invention, a pixel is understood to be a single pixel of the display. For example, in a black-and-white display, a pixel represents a bright-dark contrast, for example, by allowing the pixel to pass light of a backlight or not. In a color display, a pixel consists of a single color information, for example, a red color information that similar to a color filter can pass only the red spectral component of the backlight of the display or not. A combination of differently colored pixels, for example red, green and blue pixels, creates the color of the display. An arrangement of a red, a green and a blue pixel is referred to in the context of this invention as an RGB sequence.

For example, the display of the smartphone "Galaxy S I9000" Fa. Samsung®, rectangular or square pixels, which consist of an RGB sequence of a red, green and blue pixels, with a plurality of these RGB sequences alternately in lines and Columns are arranged side by side or one above the other. This results in an xy-matrix consisting of one Variety of RGB sequences, where at no point two same-colored pixels contiguous or abut each other. With the resolution or number of 480x800 pixels and a screen diagonal of 10.2 cm, it follows that each individual pixel occupies an approximately square area with an average edge length of about 0.11 mm.

Particularly preferably, the grid-like arrangement of optically active microstructures is adapted to the grid-like arrangement of pixels of the display such that the microstructures have the same dimensions as the pixels of the display and are arranged in the same grid. Based on the example of the smartphone "Galaxy S I9000" from Samsung®, the microstructures would thus have an approximately square surface with an edge length of about 0.11 mm and would be arranged in rows and columns next to or above one another like a matrix.

According to a further preferred embodiment, not only one pixel, but several pixels are assigned to a microstructure. For example, three RGB sequences on top of each other in a 3x3 matrix of 9 pixels, so that a single microstructure each has the triple dimension or the nine-fold area compared to a microstructure of the previous example, i. an edge length of 0.33 mm. The dimensions of a respective microstructure may thus be an integer multiple of the dimensions of a pixel or a group of pixels of the display.

Conversely, however, it is also possible that a plurality of microstructures are each assigned to a pixel of the display. For example, one pixel is assigned four microstructures arranged in a square or rectangular 2x2 matrix. Assignment in this context does not just mean that a special pixel or a special Assignment of pixels of the display of a particular microstructure is assigned, for example, the pixel in the 7th row and the 3rd column of the microstructure in the 14th row and the 6th column. Rather, association also means that any pixel or arrangement of pixels can interact with any microstructure of the verification element.

Generally, the dimensions of a particular microstructure may be n / m times the dimensions of a pixel or group of pixels of the display, where n and m are each a natural number except zero, i. one of the positive integers 1 or 2 or 3 or 4 etc.

Of course, neither the pixels of the display nor the microstructures need to have a square shape. Rather, any shape is possible, for example, rectangular, round or triangular. Also, neither the pixels of the display nor the microstructures need to be arranged in a rectangular nxm matrix. Rather, any grid-like arrangement is possible, for example, a parallelogram-like matrix or an arbitrary offset from line to line of a matrix.

For example, an RGB sequence can also consist of five pixels. A pixel of a certain color, for example the blue pixel, is arranged on a tip in the middle of the RGB sequence, one red pixel on the top left and bottom right and one green pixel on the bottom left and one pixel right upper side of the blue pixel.

Furthermore, in one row, the order of pixels within an RGB sequence may be opposite to the corresponding order of an adjacent one Be changed line. For example, in a row, an RGB sequence may consist of a red pixel next to a blue pixel next to a green pixel, and in the next line, a green pixel next to a blue pixel next to a red pixel. The blue pixels of both lines thus border each other, the red and green pixels alternate from line to line.

According to a preferred embodiment, the optically active structures are formed by a grid-like arrangement of at least translucent, preferably transparent microlenses and / or microprisms.

According to a further preferred embodiment, the microprisms each consist of two flanks which are arranged at a certain angle to one another, wherein only the first flank is provided with an opaque surface coating.

It is particularly advantageous to generate a security and / or verification element, which requires a very high technical and financial effort for an adjustment due to its complexity for a counterfeiter and at the same time can be applied to a layman easily and without deeper technical understanding.

A display, ie a display device, which can alternately display different information or even no information, is preferably an active display with its own illumination source, which illuminates the display from the back. Likewise, the display can also be a passive display without its own illumination source, with a reflective surface, which is arranged on the back of the display, reflecting daylight or room light and thus illuminates the display indirectly. The invention is preferably also applicable to a novel transparent display whose Body is perceived by a viewer as (nearly) transparent. In this case, the transparent display itself acts as a (nearly) transparent window and the information displayed on the transparent display is displayed as a single or multi-colored haze of the window, which influence or attenuate the light passing through the transparent display.

The hand-held device is, for example, a mobile phone or smartphone, a digital camera, digital clock, a credit card or an identification document, for example a passport or an identification card, with a display or a portable playback device for video or audio signals.

For the purposes of this invention, information is not or only barely recognizable whenever a viewer sees or perceives it without aids from the surrounding information or only at random and weakly. In the same sense, information is always not or only barely legible if a viewer the alphanumeric or textual content of the information without aids from the surrounding information is not or only accidentally and weakly pronounced or read or can not interpret properly.

If the display has a higher resolution than the grid-like arrangement of optically active microstructures of the verification element, according to a further preferred embodiment, a grid with a reduced resolution can be displayed on the display, the reduced resolution corresponding to the resolution of the grid-like arrangement of optically active microstructures is adapted to the verification element. For example, colored lines may appear on the display, whose line spacing corresponds to the spacing of adjacent microstructures of the verification element.

According to a further preferred embodiment, at least one third information is contained in the first information. The third information covers only a portion of the surface of the first information, so that the viewer can recognize both the hidden information and the second information.

The third information is preferably recognizable and / or readable to the viewer in the visible wavelength range without aids. Alternatively, the third information may not be visible to a viewer in the visible wavelength range, for example, by being recognizable in the ultraviolet or infrared wavelength range. Alternatively, the third information can also be visible or recognizable for a viewer both in the visible and in the invisible wavelength range, for example by being recognizable in the visible and also in the ultraviolet or infrared wavelength range. Visible here means that a viewer can optically perceive information without aids, recognizable means that a viewer can perceive information only by means of aids, for example by means of measuring devices.

This third information may in this case represent an alphanumeric text, a symbol or any graphic and be applied to the top or bottom of the transparent area of the substrate in which the first information is located. The application may in this case preferably by means of printing processes, for example printing opaque or translucent colors by means of offset printing, or by vapor deposition, such as PVD (physical vapor deposition or physical vapor deposition) or CVD (chemical vapor deposition).

Furthermore, a layer may be applied to the top or bottom of the transparent region, the third information being generated by partially ablating this layer. This is done, for example, by a part of the layer by means of a known from the prior art washing method (as it is, for example EP 1 023 499 A1 is known), by laser ablation or by mechanical methods (for example, by planing) is removed again.

Furthermore, the third information can be formed by a grid of line-shaped and / or punctiform elements. Particularly preferably, the linear and / or punctiform elements of the grid of the third information are offset relative to the linear and / or punctiform elements of the grid of the first information and / or have a different line thickness or a different point diameter.

The invention is an extension of the subject matter WO 2009/019038 A1 is the subject and scope of the WO 2009/019038 A1 in this regard is included in this invention. This means in particular that corresponding embodiments, embodiments and concretizations of WO 2009/019038 A1 can also be applied to this invention.

The advantages of the invention will be explained with reference to the following examples and additional figures. The described individual features and embodiments described below are taken individually innovative, but also inventive in combination. The examples illustrate preferred embodiments, to which, however, the invention should not be limited in any way. The proportions shown in the figures do not correspond to the conditions present in reality and serve only to improve the clarity. The illustrations in the figures are highly schematized for better understanding and do not reflect the realities. For this purpose, the described embodiments are reduced for better clarity due to the essential core information. In the practical implementation significantly more complex patterns or images in single or multi-color printing can be used. The information presented in the following examples can also be replaced by arbitrarily complex image or text information.

The various embodiments are not limited to use in the form described, but can be combined to increase the effects with each other.

Fig.1

ein erfindungsgemäßes Verifikationselement, bei dem die erste Information durch brechende Prägestrukturen in Form von Mikrolinsen gebildet wird,

Fig. 2

ein erfindungsgemäßes Verifikationselement, bei dem die erste Information durch Mikroprismen gebildet wird,

Fig. 3

ein erfindungsgemäßes Verifikationselement, bei dem die erste Information durch einseitig bedampfte Mikroprismen gebildet wird.

In detail, show schematically:

Fig.1

a verification element according to the invention, in which the first information is formed by refractive embossing structures in the form of microlenses,

Fig. 2

a verification element according to the invention, in which the first information is formed by microprisms,

Fig. 3

a verification element according to the invention, in which the first information is formed by unilaterally vaporized microprisms.

Fig.1 shows an actively lit display 1, which consists of an alternating arrangement of red r, green g and blue b pixels, wherein the arrangement of red, green and blue pixels repeats periodically with a period p. If a grid of microlenses 2, which have the same period p as the pixels of the display 1, are arranged above the display 1, a microlens 2 is located above each arrangement of a red, green and blue pixel.

The dimension of the individual pixels of the display 1 is below the resolution of the human eye. If all pixels have a similar or the same brightness, the display 1 appears to a viewer as a homogeneous white area. As is known, the human eye has a particularly high sensitivity during the day in the green spectral range. Thus, if a display is used in which all the pixels have the same lateral dimensions, i. E. For example, if the green pixels are the same diameter or the same width and length as the red or blue pixels, the brightness of the green pixels must be reduced from the brightness of the red and blue pixels, so that all the pixels or colors provide the same brightness impression to a human eye produce and thus gives the impression of a homogeneous white area. Alternatively, a display may be used in which different colored pixels have different lateral dimensions, i. For example, the green pixels have a smaller area than the red and blue pixels.

If the distance between the display 1 and the lenticular grid 2 also corresponds to the focal length of the lenses, then all the light beams 3 which are emitted perpendicularly by the pixels which are located in the focal point 4 of the lens are directed to the observer. The distance of the observer from the security element is in this case large compared to the lateral dimensions of the verification element, so that all light rays that run from the verification element to the viewer, run almost parallel. The lenticular appears when viewed vertically either red, green or blue, depending on which pixel is located in the focal point 4 of the lenses. If the lenses are divided into different subregions 5 and 6 and the individual subregions 5 and 6 are shifted relative to one another, for example all lenses in subarea 5 appear green and all lenses in subarea 6 blue when viewed vertically.

In the case of non-vertical or oblique viewing of the verification element, a color change results since, as is known, the focal point 4 also shifts with the viewing direction and the focal point 4 strikes a pixel of a different color. For example, if a viewer looks at an angle of about 10 ° from the right (in relation to the vertical in Fig.1 ) on the verification element, the sub-area 5 appears red, instead of green as viewed vertically, and the sub-area 6 green, instead of blue, as in vertical viewing.

The verification element itself, i. the grid-like arrangement of microlenses without the display 1, appears to a viewer only as a matter of matter, since the background or the environment is far outside the focal plane of the microlenses.

Preferably, the lenses are divided into different subregions 5 and 6 and the individual subregions 5 and 6 are shifted from one another, so that, for example, all the lenses in a first subarea 5 appear green and all lenses in a second subarea blue.

The microlenses are preferably designed as rotationally symmetrical lenses, such as spherical or aspherical lenses, as cylindrical lenses or as Fresnel lenses.

The use of Fresnel lenses depends on the ratio of the pixel size of the display to the technically possible or technically advantageous embossing depth or height of the lens. In the case of hemispherical lenses, the result is a lens height or embossing depth which corresponds to half the lateral dimension of a pixel of the display, ie preferably 50 μm embossing depth or height of the lens, for example for a 100 μm pixel width. For a foil strip on a banknote, such lens heights would be too great, since the foil strip would become too thick, so that it would be necessary to resort to Fresnel lenses which are known to have a much smaller height. On a map, however, hemispherical lenses with such dimensions are quite usable.

Fig. 2 shows a verification element according to the invention, in which the first information is formed by microprisms.

The emission characteristic of a liquid crystal display is usually anisotropic, i. The brightness of the display decreases from a vertical view to a view at grazing angle. If the display is tilted, the display will appear differently bright for a viewer.

Microprisms, ie prisms with dimensions in the micrometer range, divert the direction of propagation of light something known. Is thus according to Fig. 2 arranged a verification element with a grid of microprisms 11 in front of a liquid crystal display 10, can produce changed brightness differences.

In a first region 12, in which the verification element has no microprisms, a viewer sees the display 10 with its full brightness and at a viewing angle 15, which is inclined for example by 30 ° with respect to the vertical, the display with reduced brightness ,

In a region 13 in which the verification element has microprisms, the microprisms redirect the light in such a way that a viewer, when viewed perpendicularly, 16 sees the light originally emitted by the display at an angle of, for example, 10 ° with respect to the vertical. In vertical view 16, the brightness of the display with the superior microprisms appears therefore reduced. The bright light originally emitted by the display in the vertical direction is deflected by the microprisms in the direction 17, so that the viewer from this direction appears brighter than in the area without microprisms.

Areas with and without microprisms thus appear brighter or darker to a viewer from different areas, i. a surface area with microprisms is darker when viewed perpendicularly than a surface area without microprisms. At greater angles, the difference in brightness turns and the area with the microprisms appears brighter than the area without microprisms.

The lateral dimensions of the microprisms can, as in Fig. 2 shown to be smaller than the pixels of the display. This has the advantage that the microprisms have a lower embossing depth than microprisms whose lateral dimensions are larger than those of the pixels of the display, ie corresponding security elements are thinner and usually less expensive manufacture. However, if the thickness of the verification element plays a rather subordinate role, the lateral dimensions of the microprisms may also be greater than those of the pixels of the display.

The microprisms may be arranged on the top and / or bottom of a verification element. To protect against molding, the microprisms, as well as the lens structures described above, may be embedded in a protective lacquer which has a different refractive index than the prisms, which are preferably embossed in an embossing lacquer.

Similar effects can be generated via diffractive structures instead of refraction with prisms. Thus, diffraction gratings deflect a portion of the incident light in transmission into the corresponding diffraction orders and reduce the brightness in a perpendicular view, while the brightness can be increased at other angles and diffraction-related color effects can occur.

Instead of microprisms, it is also possible to use light-scattering structures, for example matt structures, which do not reflect light but scatter it over a larger angular range and thus likewise reduce the brightness in a vertical plan view and increase it at other angular ranges.

According to a further preferred embodiment, an array of diverging lenses, preferably plano-concave lenses, is used as a grid-like arrangement of optically active microstructures.

About the curvature of the diverging lenses, a color change is generated depending on the viewing direction, if the respective diverging lens on the Size of a pixel is tuned, or a light / dark difference, if the respective diverging lens is at least twice as large as a pixel.

For example, a diverging lens could cover a single blue pixel. The light cone of the blue b pixel is then widened and appears darker in vertical plan, i. a white image will be less blue in vertical view and therefore yellowish. In a second area, the diverging lenses could be staggered, for example over a green g pixel. Here then the green component would be reduced in vertical supervision, i. a white representation will appear magenta-like. Alternatively, the display could glow red or green all over. Then once the first and once the second area depending on the viewing angle would appear brighter or darker than the display.

According to a further preferred embodiment, to further increase the protection against counterfeiting, a second film is applied at least to the region of the verification element in which the lens or mirror structures are located. This second film covers the lens or mirror structures, so that it is no longer possible for a counterfeiter to mold the otherwise exposed lens or mirror structures. The second film is preferably attached to its edge with the verification element, for example glued or welded, and additionally attached to the tips of the lens or mirror structures within the surface of the verification element. In this way, it is advantageously achieved that the second foil can not be detached from the verification element in a counterfeit attack without destroying the lens or mirror structures.

Fig. 3 shows a verification element 20 according to the invention, in which the first information is formed by unilaterally vaporized microprisms.

The microprisms each consist of two flanks, which are arranged at a certain angle to each other. Only the first flank is provided with an opaque surface coating 21, the second flank has no or at least a translucent surface coating. The surface coating 21 is preferably vapor-deposited onto the respective flank, for example by means of PVD (physical vapor deposition).

The result is a so-called blind effect, since the display is covered by the flank of the microprisms with the vaporized surface. From the other side, i. From the side of the microprisms, which has no surface coating, you can see through it like a blind.

According to Fig. 3 Even different directions can be generated depending on the direction. In a partial region 22, sawtooth gratings of a first orientation in transmission from direction 25 and 26 are opaque and thus opaque. From direction 27 you can see through the "slats" as through a transparent line grid.

In area 23, no sawtooth gratings are embossed in the verification element, so that it is not possible to see through the surface coating 21 from all three directions 25, 26 and 27. The verification element is thus opaque from all viewing directions.

In area 24, the sawtooth grids are aligned so that you can see through the slats from the direction of view 25 and the display is visible. If the sawtooth grid is tuned so that there is only one green, blue or red pixel of the display under a single sawtooth, it is possible not only to create a light-dark difference, but also to change the color impression when viewed from the side. This can be done partially, ie only on a single or a few pixels, as well as over a large area. In the viewing angle 27, the display appears in the region 22, for example, green and in the region 24, for example, red.

According to a further preferred embodiment, a superficial first motif is represented by the outline of the partial metallization, which is already perceived without a display.

Claims (7)

A method of verifying documents of value, such as banknotes, securities, credit, debit or ID cards, passports, documents, tickets, tickets and the like, labels, packaging, tax stamps, cigarette strips or other product security or marketing campaign items containing at least one substrate have a translucent area, wherein a first information is arranged in at least one light-permeable region of the substrate, using a separate display consisting of a grid-like arrangement of pixels, wherein a second information which correlates with the first information is displayed at least in regions by the separate display, wherein in the first and / or second information another information that is not recognizable and / or readable by a viewer without aids is hidden, the substrate is placed with its first information about the second information displayed on the separate display, the hidden information becomes recognizable and / or readable,
characterized in that
the first information is formed by a grid-like arrangement of optically active microstructures, wherein the grid-like arrangement of optically active microstructures is adapted to the grid-like arrangement of pixels of the display. Method for verifying or verifying valuables having a display consisting of a grid-like arrangement of pixels, wherein a separate verification element is provided, which has at least one substrate with at least one light-transmissive region, a first information being arranged in at least one light-permeable region of the substrate, wherein a second information is displayed by the display at least regionally, which correlates with the first information, wherein in the first and / or second information another, not visible to a viewer without aids and / or readable information is hidden, the substrate is placed with its first information about the second information displayed on the display, the hidden information becomes recognizable and / or readable,
characterized in that
the first information is formed by a grid-like arrangement of optically active microstructures, wherein the grid-like arrangement of optically active microstructures is adapted to the grid-like arrangement of pixels of the display. A method according to claim 1 or 2, characterized in that the optically active structures by a grid-like arrangement of at least translucent, preferably transparent microlenses and / or microprisms is formed. A method according to claim 3, characterized in that the microprisms each consist of two flanks, which in a certain Are arranged angle to each other, wherein only the first edge is provided with an opaque surface coating. Method according to one of the preceding claims, characterized in that in the first information at least a third information is included. Device for carrying out the method according to one of claims 1 or 3 to 5, characterized in that the display is a screen of a computer, a notebook or a laptop, a monitor of a cash register of a POS system or a display of a handset. Device for carrying out the method according to one of claims 2 to 5, characterized in that the valuable object with display is a computer, a notebook or a laptop, a cash register of a cash register system or a handheld device.

Images