EP3898248B1 - Élément de sécurité actif dans le domaine des thz et son procédé de fabrication - Google Patents

Élément de sécurité actif dans le domaine des thz et son procédé de fabrication Download PDF

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Publication number
EP3898248B1
EP3898248B1 EP19831592.1A EP19831592A EP3898248B1 EP 3898248 B1 EP3898248 B1 EP 3898248B1 EP 19831592 A EP19831592 A EP 19831592A EP 3898248 B1 EP3898248 B1 EP 3898248B1
Authority
EP
European Patent Office
Prior art keywords
grating structure
line grating
layer
security element
thz
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
EP19831592.1A
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German (de)
English (en)
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EP3898248A1 (fr
Inventor
Hans Lochbihler
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Giesecke and Devrient Currency Technology GmbH
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Giesecke and Devrient Currency Technology GmbH
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Publication of EP3898248A1 publication Critical patent/EP3898248A1/fr
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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B42—BOOKBINDING; ALBUMS; FILES; SPECIAL PRINTED MATTER
    • B42D—BOOKS; BOOK COVERS; LOOSE LEAVES; PRINTED MATTER CHARACTERISED BY IDENTIFICATION OR SECURITY FEATURES; PRINTED MATTER OF SPECIAL FORMAT OR STYLE NOT OTHERWISE PROVIDED FOR; DEVICES FOR USE THEREWITH AND NOT OTHERWISE PROVIDED FOR; MOVABLE-STRIP WRITING OR READING APPARATUS
    • B42D25/00—Information-bearing cards or sheet-like structures characterised by identification or security features; Manufacture thereof
    • B42D25/20—Information-bearing cards or sheet-like structures characterised by identification or security features; Manufacture thereof characterised by a particular use or purpose
    • B42D25/29—Securities; Bank notes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B42—BOOKBINDING; ALBUMS; FILES; SPECIAL PRINTED MATTER
    • B42D—BOOKS; BOOK COVERS; LOOSE LEAVES; PRINTED MATTER CHARACTERISED BY IDENTIFICATION OR SECURITY FEATURES; PRINTED MATTER OF SPECIAL FORMAT OR STYLE NOT OTHERWISE PROVIDED FOR; DEVICES FOR USE THEREWITH AND NOT OTHERWISE PROVIDED FOR; MOVABLE-STRIP WRITING OR READING APPARATUS
    • B42D25/00—Information-bearing cards or sheet-like structures characterised by identification or security features; Manufacture thereof
    • B42D25/30—Identification or security features, e.g. for preventing forgery
    • B42D25/328—Diffraction gratings; Holograms
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B42—BOOKBINDING; ALBUMS; FILES; SPECIAL PRINTED MATTER
    • B42D—BOOKS; BOOK COVERS; LOOSE LEAVES; PRINTED MATTER CHARACTERISED BY IDENTIFICATION OR SECURITY FEATURES; PRINTED MATTER OF SPECIAL FORMAT OR STYLE NOT OTHERWISE PROVIDED FOR; DEVICES FOR USE THEREWITH AND NOT OTHERWISE PROVIDED FOR; MOVABLE-STRIP WRITING OR READING APPARATUS
    • B42D25/00—Information-bearing cards or sheet-like structures characterised by identification or security features; Manufacture thereof
    • B42D25/30—Identification or security features, e.g. for preventing forgery
    • B42D25/36—Identification or security features, e.g. for preventing forgery comprising special materials
    • B42D25/373—Metallic materials
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B42—BOOKBINDING; ALBUMS; FILES; SPECIAL PRINTED MATTER
    • B42D—BOOKS; BOOK COVERS; LOOSE LEAVES; PRINTED MATTER CHARACTERISED BY IDENTIFICATION OR SECURITY FEATURES; PRINTED MATTER OF SPECIAL FORMAT OR STYLE NOT OTHERWISE PROVIDED FOR; DEVICES FOR USE THEREWITH AND NOT OTHERWISE PROVIDED FOR; MOVABLE-STRIP WRITING OR READING APPARATUS
    • B42D25/00—Information-bearing cards or sheet-like structures characterised by identification or security features; Manufacture thereof
    • B42D25/40—Manufacture
    • B42D25/405—Marking
    • B42D25/425—Marking by deformation, e.g. embossing
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B42—BOOKBINDING; ALBUMS; FILES; SPECIAL PRINTED MATTER
    • B42D—BOOKS; BOOK COVERS; LOOSE LEAVES; PRINTED MATTER CHARACTERISED BY IDENTIFICATION OR SECURITY FEATURES; PRINTED MATTER OF SPECIAL FORMAT OR STYLE NOT OTHERWISE PROVIDED FOR; DEVICES FOR USE THEREWITH AND NOT OTHERWISE PROVIDED FOR; MOVABLE-STRIP WRITING OR READING APPARATUS
    • B42D25/00—Information-bearing cards or sheet-like structures characterised by identification or security features; Manufacture thereof
    • B42D25/40—Manufacture
    • B42D25/45—Associating two or more layers
    • G—PHYSICS
    • G07—CHECKING-DEVICES
    • G07D—HANDLING OF COINS OR VALUABLE PAPERS, e.g. TESTING, SORTING BY DENOMINATIONS, COUNTING, DISPENSING, CHANGING OR DEPOSITING
    • G07D7/00—Testing specially adapted to determine the identity or genuineness of valuable papers or for segregating those which are unacceptable, e.g. banknotes that are alien to a currency
    • G07D7/003—Testing specially adapted to determine the identity or genuineness of valuable papers or for segregating those which are unacceptable, e.g. banknotes that are alien to a currency using security elements
    • G07D7/0032—Testing specially adapted to determine the identity or genuineness of valuable papers or for segregating those which are unacceptable, e.g. banknotes that are alien to a currency using security elements using holograms
    • G—PHYSICS
    • G07—CHECKING-DEVICES
    • G07D—HANDLING OF COINS OR VALUABLE PAPERS, e.g. TESTING, SORTING BY DENOMINATIONS, COUNTING, DISPENSING, CHANGING OR DEPOSITING
    • G07D7/00—Testing specially adapted to determine the identity or genuineness of valuable papers or for segregating those which are unacceptable, e.g. banknotes that are alien to a currency
    • G07D7/06—Testing specially adapted to determine the identity or genuineness of valuable papers or for segregating those which are unacceptable, e.g. banknotes that are alien to a currency using wave or particle radiation
    • G—PHYSICS
    • G07—CHECKING-DEVICES
    • G07D—HANDLING OF COINS OR VALUABLE PAPERS, e.g. TESTING, SORTING BY DENOMINATIONS, COUNTING, DISPENSING, CHANGING OR DEPOSITING
    • G07D7/00—Testing specially adapted to determine the identity or genuineness of valuable papers or for segregating those which are unacceptable, e.g. banknotes that are alien to a currency
    • G07D7/06—Testing specially adapted to determine the identity or genuineness of valuable papers or for segregating those which are unacceptable, e.g. banknotes that are alien to a currency using wave or particle radiation
    • G07D7/12—Visible light, infrared or ultraviolet radiation
    • G07D7/1205—Testing spectral properties

Definitions

  • the invention relates to a security element that acts in the THz range for the production of ID cards, cards, passports or documents of value, such as banknotes, checks or the like, which has a lattice structure that is not visible to the naked eye and is formed, for example, by a metal layer.
  • the invention further relates to a method for producing such a security element.
  • the invention further relates to a document of value with such a security element.
  • Security elements are used to protect documents of value, such as banknotes, checks or the like, against counterfeiting.
  • covert security elements which are not readily recognizable to a user of the value document and are generally subjected to a machine authenticity check
  • open security elements which are recognizable to a user.
  • An example of overt security elements are holograms.
  • the invention is therefore based on the object of creating a security element that can be detected with THz radiation and is therefore covered, which has even more favorable properties in the THz range and requires little additional effort in series production. It should also be able to be combined particularly advantageously with overt security features.
  • a security element for the production of documents of value, such as banknotes, checks or the like, which has a grid structure that is not visible to the naked eye and is formed in a first layer, preferably a metal layer, which is arranged in a dielectric and is opaque to THz radiation is, wherein the first layer is in a first plane and has, for example, a layer thickness between 6 nm and 1 micron.
  • the first layer In the first layer there are longitudinal slits that are transparent to THz radiation and are next to one another educated.
  • the first layer is embedded in a dielectric that is transparent to THz radiation.
  • the longitudinal slits are arranged next to one another periodically or quasi-periodically with a period, for example between 8 ⁇ m and 200 ⁇ m.
  • the width of the longitudinal slits is not more than 1/5, preferably 1/10, of the period.
  • the slots are at least 5 times as long as the period.
  • a second layer is also arranged in the dielectric in a second plane, which is parallel to the first plane. This is also formed from a layer material that is opaque to THz radiation and has a second line grating structure. This is inverted to the first line grating structure and offset by half a period. As a result, the second line lattice structure forms longitudinal webs which, when viewed from above, exactly fill the gaps left by the first longitudinal slots in the first layer.
  • the second line lattice structure is formed from longitudinal webs running in parallel, with one of the longitudinal webs of the second layer lying under each of the longitudinal slots of the first layer.
  • the superimposed pairs of longitudinal slots and longitudinal webs each have essentially (i.e. within the scope of manufacturing tolerances, which can be e.g. 5-10%) the same width, so that the mentioned gap filling is realized.
  • the distance between the first and second levels is between 50 nm and 100 ⁇ m, particularly preferably between 500 nm and 5 ⁇ m.
  • the period is more preferably in the same interval.
  • Quasi-periodic means that the grating period fluctuates around a mean value. This fluctuation can preferably be up to half a period, particularly preferably up to 1/10 period.
  • periodic structures are covered by a quasi-periodic arrangement, in which the period varies due to production.
  • Such quasi-periodic arrangements of slot structures also have an increased TM transmission in the THz range.
  • the first and/or the second layer comprises a color-shift coating. This improves visual recognition - in addition to machine evaluation, which takes place in the THZ area.
  • DE 102015009584 A1 Next are those from the DE 102015009584 A1 known combinations with security features that can be seen with the naked eye.
  • hologram structures, sub-wavelength gratings with periods between 200 nm and 500 nm, sawtooth structures, etc. come into question DE 102015009584 A1 is fully integrated here in this regard.
  • a first layer which is formed from a layer material that is opaque to THz radiation, is arranged in a first plane in a dielectric that is transparent to THz radiation. It has a periodic or quasi-periodic first line lattice structure, which cannot be seen with the naked eye, and consists of parallel longitudinal slits, which produce longitudinal slits in the first layer. A width of the longitudinal slits is not larger than 1/5 of the period, preferably not larger than 1/10 of the period.
  • a second layer which is also formed from a layer material that is opaque to THz radiation, is arranged in the dielectric in a second plane, which is parallel to the first plane.
  • a second line grating structure is formed. It is inverted to the first line grating structure and offset by half a period. This in turn ensures that the longitudinal webs, which are formed in the second layer, exactly fill the longitudinal slots in a plan view.
  • the security element according to the invention can be checked in the THz range, since the slot structure is transparent for THz radiation with TM polarization, but opaque for TE polarization, or vice versa. Due to the slit structure, the security feature acts as a polarizer that lets through THz radiation with one polarization. If the incident THz radiation is correspondingly polarized, a large proportion of this polarization component passes through the security element. The security element can thus be subjected to a machine authenticity check very easily.
  • a THz radiation source and a THz detector are used for this purpose. Ideally, the THz radiation is polarized, with the security element also being able to be detected with unpolarized THz radiation.
  • a polarizer which acts as an analyzer, must be arranged in front of the detector.
  • the authenticity check can be carried out with a measurement in transmission as well as in reflection.
  • the security element acts as a polarizer that lets the THz radiation with TM polarization through. If the THz radiation is correspondingly linearly polarized, this component passes through the security element for the most part and becomes polarized with the same polarization completely detected by the analyzer. If the polarization directions of the radiation source and detector are perpendicular to one another, the trivial case of a hole in the security element can be ruled out. This would also be visually verifiable.
  • a vertically polarized THz radiation is rotated when passing through the security element and the analyzer with horizontal polarization can receive the THz signal.
  • the contrast can be increased by recording with two or more different polarization directions.
  • the machine authenticity check can thus be carried out both with parallel orientation of the polarization of beam source and detector and with crossed orientation.
  • the rotation of the security feature is a rotation of the security feature in the plane that is defined by the periodically or quasi-periodically adjacent longitudinal slots.
  • the slit structure cannot be seen with the naked eye, at least for an inexperienced observer and/or in a mere top view, since the width of the longitudinal slits is not greater than 1/5 of the period. If this upper limit is lowered, the slit structure becomes very difficult or impossible to recognize even for a practiced observer who is looking for the slit structure and/or when using special viewing techniques (e.g. certain tilting and rotating of the security element). It is particularly preferred that the width of the longitudinal slits is not greater than 1/10 of the period, since the slit structure then produces a security feature that is particularly well concealed.
  • the double structure which provides longitudinal webs under the slits that are formed in the first layer, which exactly match the slit width, the transmission and reflection properties in the THz range are improved.
  • the security element is designed in such a way that the layer comprises a plurality of fields, between which a longitudinal direction of the longitudinal slits differs. So the fields have an individual angular orientation of their directions of the longitudinal slots. Such individual fields then appear with different brightness depending on the rotational position and/or orientation to the THz detector.
  • the configuration of the lattice structure in the layer is virtually imperceptible to the naked eye. A potential counterfeiter thus receives no indication of the presence of such a security feature.
  • the layer hardly differs from a layer that is formed without the longitudinal slits.
  • it is possible to combine the security element with a visually visible structure e.g. by additionally providing the areas of the layer between the longitudinal slits with a further security feature that can be seen with the naked eye.
  • the security element has covert properties that can be seen with THz radiation and additional ones that can be seen with the naked eye, i. H. open security properties.
  • the additional security feature that can be seen with the naked eye can be, in particular, a metalized hologram, a sub-wavelength grating with periods of 200 nm to 500 nm, a sawtooth structure and/or a color-shift coating.
  • the production method according to the invention can be designed in such a way that the preferred configurations and embodiments of the security element described are produced.
  • the security element 4 is designed in such a way that it filters radiation in the THz range in a specific way and at the same time is designed in such a way that it cannot be seen with the naked eye.
  • the security element 4 thus provides a concealed security feature that can be read with a corresponding detector.
  • the THz structure is im visible wavelength range almost opaque or at least not recognizable. This does not preclude the structure from being combined or overlaid with a visually transparent structure, as in the embodiments of FIGS Figures 2B to 2D the case is.
  • the security element 4 can be open on both sides (eg when used as an element spanning a window) or on one side. In addition, it can be completely embedded in the substrate, which is transparent to THz radiation. Examples of the substrate or the dielectric are paper or plastic.
  • FIG. 1 shows a sectional representation of the security element 4, which has a dielectric 6 arranged on a carrier, which is not described in more detail.
  • a first line grating structure 8 is embedded in the dielectric 6 , which is transparent to THz radiation, and is made up of a coating that absorbs THz radiation and is located in a first plane 10 .
  • a second plane 12 parallel thereto, which is a distance h lower there is a second line grating structure 14 in the dielectric 6, which is also made of a THz radiation-absorbing material, preferably made of the same material as the first line grating structure 8.
  • the first and the second line grating structure 8.14 form a bi-layer grating 16.
  • the first and the second line grating structure 8.14 are inverted to each other.
  • the first line grating structure 8 consists of metallic strips 18 which are spaced apart from one another by longitudinal slots 20 . This structure is arranged according to a period p.
  • the second line grating structure 14 is inverted for this purpose. It has longitudinal slits 24 at those points where the first line grating structure 8 has the strips 18 and strips 22 at the points of the longitudinal slits 20.
  • the layer that forms the strips 18 has a thickness t1, for example, the layer that forms the strips . 22 forms a thickness t2.
  • the strips 18, 22, and thus the line grating structures 8,14 have a refractive index n and are completely surrounded by the dielectric 6, which preferably and optionally has the same refractive index n above and below the line grating structures 8,14.
  • the refractive indices in the dielectric 6 can also vary.
  • the inverted shape that the second line grating structure 14 has in relation to the first line grating structure 8 means that the width d of the strips 18 of the first line grating structure 8 corresponds exactly to the width of the longitudinal slots 24 of the second line grating structure 14. The same applies to the width s of the longitudinal slots 20 of the first line grating structure 8 and the strips 22 of the second line grating structure 14.
  • the inverted line gratings are also shifted relatively by half a period in the plane 10 or 12 so that in a top view of the security element 4 (according to the viewing direction in Figure 2A from top to bottom) a gapless layer is formed by the strips 18 and 22.
  • FIG 2A it is shown that a plane wave is incident on the security element 4 at an azimuth angle ph and an elevation angle th.
  • This incident radiation S is partially transmitted as transmitted radiation T and partially reflected as reflected radiation R.
  • the properties of this effect on radiation in the THz range are described below on the basis of Figures 3 to 7 explained in more detail.
  • Figures 2B to 2D differ from those of Figure 2A by the design of the strips 18. They are used to additionally create a visually perceptible effect. Despite this visually perceptible effect, the structure effective in the THz range cannot be recognized. The covert security property is therefore retained.
  • the structure described above for authenticity detection in the THz range is preferably produced on film substrates and can then be applied to banknotes 2, for example.
  • a metallically reflective surface is not very attractive to an observer. It is possible to overprint this area.
  • FIG. 2B A superimposition with various metalized security features known per se is therefore advantageous.
  • Such an overlay can be done with embossed holograms, as in Figure 2B is shown schematically.
  • the strips of the first line grating structure 8 consist of a hologram structure 26. It is opaque to THz radiation, so that the hidden security property of the security element 4 is retained.
  • Such holograms consist of grating arrangements with periods of about 500 nm to 1500 nm.
  • the grating profile has a sinusoidal or rectangular shape with pitches of about 100 nm to 300 nm.
  • the structure is metallized over the entire surface. Aluminum, silver or copper with layer thicknesses of approx.
  • the superimposition with the THz structure described above means that narrow periodic regions of the embossed hologram or mirror strips lie on the lower level 12 . Since the period of the hologram grating is significantly smaller than the grating period of the THz structure, there is no additional interaction in the THz range with this structure. This is because the period of the hologram is orders of magnitude smaller than the wavelength of the THz radiation. There is therefore a comparable transmission in the THz range as in the case of the bi-layer grating 16 described above.
  • the strips include a color-shift coating 28, which can optionally also be applied to the strips of the second line grating structure 14.
  • the color shift coatings 28, 30 produce a visually perceptible effect. Since they include a metal layer or another coating that is opaque to THz radiation, the effect of the security element 4 as a covered security feature is retained here as well.
  • the color-shift structure consists, for example, of a semi-transparent chromium layer, a dielectric spacer layer, preferably made of silicon dioxide, and a metallic mirror layer underneath, e.g. e.g. aluminium. This layer structure is finally formed as a bi-layer structure 16 .
  • the surface area of the underlying structure is small compared to the total area. Therefore, the visual impression of these security features is hardly affected by the overlay with the THz structure.
  • the strips of the first line grating structure 8 are in the form of a sawtooth structure 32 . So there is a superimposition with a sawtooth structure such.
  • Known sawtooth arrangements have a lateral extent of between 1 ⁇ m and 10 ⁇ m and a height of between approximately 0.3 ⁇ m and 4 ⁇ m. Such arrangements are used to create motion and spatial effects in reflection. They are either covered with a simple metal layer or they are vaporized with a so-called color-shift structure in order to create an additional color effect.
  • the metallized structure is interrupted by the periodic arrangement of the longitudinal slots 20, under which the strips 22 lie on the lower level. In the THz range, only this combination affects the transmission, since the interaction with the sawtooth structure 32 itself is low.
  • the overlay can also be performed with (optical) sub-wavelength structures. These are 1-dimensional or 2-dimensional periodic gratings with periods between 100 nm and 500 nm, which are metallized. It remains to be mentioned that so-called metallic moth-eye structures, which can serve as an absorbent background, can also be overlaid with the structure explained above. Also, the metalized ridges will be raised instead of recessed as in the drawings above. The transmission in the THz range is identical with this vertically mirrored arrangement.
  • the above-mentioned coatings that absorb THz radiation are not limited to a simple metal layer or color-shift structures.
  • Other multilayer coatings can also be used as long as they are opaque to THz radiation - either in combination or due to an absorbing component or layer.
  • the transmission for these ridge widths is approximately zero.
  • the contrast of transmission between TM and TE polarization is in Figure 3C ) shown.
  • the calculated degree of polarization (T TM -T TE ) / (T TM + T TE ) is plotted as a function of frequency. The more these values differ from zero, the stronger the polarization effect of the bi-layer grating 16. It can be seen that the grating as a whole frequency range shown has pronounced polarization properties.
  • the other parameters are identical to those of Figures 3A-C .
  • the figure labeled A shows the transmission for TM polarization
  • the figure labeled B shows the transmission for TE polarization
  • the figure labeled C shows the contrast.
  • a variation of the height difference h does not have a significant effect on the transmission behavior in the THz range.
  • the polarization properties are hardly affected. This means that the process window in series production is not critical with regard to this parameter.
  • Figures 5A and 5B it can be seen that the spectral characteristic of the transmission is shifted towards lower frequencies for increasing periods.
  • Figure 5C it can be seen that the polarizing effect of the grating is very good for these periods in the entire spectral range shown. This shows that the transmission characteristics can be adjusted for the desired frequency band by appropriately selecting the grating period.
  • bi-layer grating 16 with periods d>50 ⁇ m can hardly be distinguished from a smooth metallic surface by an observer. This is all the less the case when such bi-layer gratings 16 are overlaid with other structures such as hologram gratings.
  • the structure corresponds schematically to the drawing of Figure 2B .
  • the structure consists of a 60 nm thick aluminum film embedded in UV varnish between two PET foils.
  • the embossed hologram consists of gratings of different azimuthal orientation with periods between 500 nm and 2 ⁇ m.
  • the profile shape is sinusoidal.
  • Figure 7A shows the spectral transmission in the range from 0.1 to 3 THz for TM and TE polarization.
  • this approach can be used to encode information that can be evaluated automatically in the THz range.
  • An example is the coding of the denomination or the value of banknotes, e.g. 5, 10, 20, 50 and 100. These numerical values (or other values) can be encoded by differently oriented areas of bi-layer gratings, preferably with areas rotated by 90°.
  • the security element can simply be subjected to an authenticity check by examining its polarization properties for radiation in the THz spectral range. Possible devices are shown in FIGS. 13 and 14 of FIG DE 102015009584 A1 .
  • the security feature 4 acts as a polarizer that lets through THz radiation with TM polarization. If the THz radiation is correspondingly linearly polarized, this component mostly passes through.
  • the THz source can be followed by a polarizer; this can be omitted if the THz source already emits the corresponding polarized radiation. After passage through the security element 4 z. B.
  • an analyzer that filters the direction of polarization according to the THz detector.
  • the contrast can be increased, ie the device is first set in the configuration with the same alignment of source radiation and detector and then with mutually orthogonal alignment. If the security element has 4 areas with differently oriented slit structures, a spatially resolving detector measures different intensities for the individual areas. This increases the reliability of the authentication of this feature.
  • a THz radiation source and a THz detector are used, which are arranged opposite one another.
  • the security element 4 is located in between and is preferably irradiated approximately perpendicularly.
  • the radiation from the THz radiation source is preferably linearly polarized and the detector is also polarization-sensitive.
  • the security element 4 is arranged in such a way that TM polarization is present for at least one area of the bi-layer grating 16 and the THz radiation reaches the detector there almost unhindered. In contrast, the transmission for the grating areas in TE polarization is blocked.
  • the polarization directions of the radiation source and detector are perpendicular to one another.
  • THz analysis can be performed at a single frequency or in a single frequency band, as well as for multiple frequencies or separate frequency bands. The latter two embodiments refine the authenticity check.

Claims (11)

  1. Élément de sécurité destiné à la production de documents de valeur, tels que des billets de banque, des chèques ou similaires, une première couche étant disposée dans un premier plan (10) dans un diélectrique (6) transparent au rayonnement THz, laquelle couche est formée d'un matériau de couche opaque au rayonnement THz et forme une structure de réseau de lignes périodique ou quasi-périodique non visible à l'oeil nu (8) qui comprend des fentes longitudinales parallèles (20) qui génèrent des lacunes dans la première couche, une largeur des fentes longitudinales (20) n'étant pas supérieure à 1/5 de la période (p), de préférence pas supérieure à 1/10 de la période (p),
    caractérisé en ce que
    une deuxième couche est disposée dans le diélectrique (10) dans un deuxième plan (12) qui est parallèle au premier plan (10), laquelle deuxième couche est également formée d'un matériau de couche opaque au rayonnement THz et forme une deuxième structure de réseau de lignes (14) qui est inversée par rapport à la première structure de réseau de lignes (8).
  2. Élément de sécurité selon la revendication 1, caractérisé en ce que la deuxième structure de réseau de lignes (14) est formée de nervures longitudinales parallèles (22), l'une des nervures longitudinales (22) de la deuxième structure de réseau de lignes (14) étant située au-dessous de chacune des fentes longitudinales (20) de la première structure de réseau de lignes (8) et les fentes longitudinales (20, 24) et nervures longitudinales (18, 22) sus-jacentes ayant chacune sensiblement la même largeur (d, s) de sorte que les nervures longitudinales (24) de la deuxième structure de réseau de lignes (14) recouvrent les fentes longitudinales (20) de la première structure de réseau de lignes (8) dans une vue de dessus du premier plan (10).
  3. Élément de sécurité selon la revendication 1 ou 2, caractérisé en ce qu'une distance (h) entre les premier et deuxième plans (10, 12) est comprise entre 50 nm et 100 µm.
  4. Élément de sécurité selon l'une des revendications 1 à 3, caractérisé en ce que la période (p) est comprise entre 10 µm et 100 µm.
  5. Élément de sécurité selon l'une des revendications 1 à 4, caractérisé en ce que les première et/ou deuxième structures de réseau de lignes (8, 14) comporte(nt) un revêtement multicouche opaque au rayonnement THz, notamment un revêtement à décalage de couleur (28, 30).
  6. Procédé de réalisation d'un élément de sécurité destiné à la production de documents de valeur, tels que des billets de banque, des chèques ou analogues, une première couche étant disposée dans un premier plan (10) dans un diélectrique (6) transparent au rayonnement THz, laquelle première couche est formée d'un matériau de couche opaque au rayonnement THz et forme une structure de réseau de lignes périodique ou quasi-périodique non visible à l'oeil nu (8) qui comprend des fentes longitudinales parallèles (20) qui génèrent des lacunes dans la première couche, une largeur des fentes longitudinales (20) n'étant pas supérieure à 1/5 de la période (p), de préférence pas supérieure à 1/10 de la période (p),
    caractérisé en ce que
    une deuxième couche est disposée dans le diélectrique (6) dans un deuxième plan (12) parallèle au premier plan (10), laquelle deuxième couche est également formée d'un matériau de couche opaque au rayonnement THz et est pourvue d'une deuxième structure de réseau de lignes (14) qui est inversée par rapport à la première structure de réseau de lignes (8).
  7. Procédé selon la revendication 6, caractérisé en ce que la deuxième structure de réseau de lignes (14) est formée de nervures longitudinales parallèles (22), l'une des nervures longitudinales (22) de la deuxième structure de réseau de lignes (14) étant disposée au-dessous de chacune des fentes longitudinales (20) de la première structure de réseau de lignes (8) et les fentes longitudinales (20, 24) et nervures longitudinales (18, 22) sus-jacentes ayant sensiblement la même largeur (d, s) de sorte que les nervures longitudinales (24) de la deuxième structure de réseau de lignes (14) recouvrent les fentes longitudinales (20) de la première structure de réseau de lignes (8) dans une vue de dessus du premier plan (10).
  8. Procédé selon la revendication 6 ou 7, caractérisé en ce qu'une distance (h) entre les premier et deuxième plans (10, 12) est comprise entre 50 nm et 100 µm.
  9. Procédé selon l'une des revendications 6 à 8, caractérisé en ce que la période (p) est comprise entre 10 µm et 100 µm.
  10. Procédé selon l'une des revendications 6 à 9, caractérisé en ce que les première et/ ou deuxième structures de réseau de lignes (8, 14) comportent un revêtement à décalage de couleur (28, 30).
  11. Document de valeur comprenant un élément de sécurité selon l'une des revendications 1 à 5.
EP19831592.1A 2018-12-17 2019-12-13 Élément de sécurité actif dans le domaine des thz et son procédé de fabrication Active EP3898248B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE102018132516.9A DE102018132516A1 (de) 2018-12-17 2018-12-17 Im THz-Bereich wirkendes Sicherheitselement und Verfahren zu dessen Herstellung
PCT/EP2019/000339 WO2020126065A1 (fr) 2018-12-17 2019-12-13 Élément de sécurité actif dans le domaine des thz et son procédé de fabrication

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EP3898248A1 EP3898248A1 (fr) 2021-10-27
EP3898248B1 true EP3898248B1 (fr) 2023-02-08

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EP (1) EP3898248B1 (fr)
CN (1) CN113195239B (fr)
DE (1) DE102018132516A1 (fr)
WO (1) WO2020126065A1 (fr)

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DE102021002600A1 (de) 2021-05-18 2022-11-24 Giesecke+Devrient Currency Technology Gmbh Wertdokument und Verfahren zur Herstellung eines Wertdokuments

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DE102011115589A1 (de) * 2011-10-11 2013-04-11 Giesecke & Devrient Gmbh Sicherheitselement
DE102014010751A1 (de) * 2014-07-21 2016-01-21 Giesecke & Devrient Gmbh Sicherheitselement mit Subwellenlängengitter
JP6484049B2 (ja) * 2015-02-03 2019-03-13 凸版印刷株式会社 偽造防止構造体、偽造防止媒体、及び、真贋判別装置
DE102015009584A1 (de) 2015-07-23 2017-02-09 Giesecke & Devrient Gmbh Sicherheitselement und Verfahren zu dessen Herstellung
DE102015010191A1 (de) * 2015-08-06 2017-02-09 Giesecke & Devrient Gmbh Sicherheitselement mit Subwellenlängengitter
DE102016013690A1 (de) * 2016-11-16 2018-05-17 Giesecke+Devrient Currency Technology Gmbh Sicherheitselement mit Subwellenlängengitter

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Publication number Publication date
CN113195239A (zh) 2021-07-30
DE102018132516A1 (de) 2020-06-18
WO2020126065A1 (fr) 2020-06-25
EP3898248A1 (fr) 2021-10-27
CN113195239B (zh) 2022-09-27

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