|Title of Invention||
"VALUE AND SECURITY PRODUCT"
|Abstract||The invention concerns a value and security product with luminescent element, consisting of a Single-layer or multi-layer substrate material, wherein at least one authenticity element is arranged on or within this substrate material. In order to be able to carry out easy visual or mechanical authenticity checking of the security document under all conditions of illumination, it is provided according to the invention that below the layer constructed as an authenticity element is provided a luminescent element which is made to light up by an electrical, optical or mechanical energy source acting from the outside. This luminescent element serves as background illumination for the authenticity element arranged above.|
|Full Text||The subject of the present invention is a value and security product with luminescent element according to the introductory part of patent claim 1.
The manufacture and use of electroluminescent films and elements is known from .the state of the art.
In DE 4 310 082 Al are presented electroluminescent films which are made from inorganic, electroluminescent pigment(s) and thermoplastic . material by extrusion or coextrusion. Basically the extrusion, or coextrusion of such a system on security papers would be conceivable, but the graphic design possibilities seem to be limited by the process logistics and the whole production process for producing a security document and the assemblies for authenticity checking required therefor seem to become very elaborate.
In DE 4 315 244 Al is described a method for producing an electroluminescent film by using sputter technology. This method too • would basically be conceivable for producing security documents, but a production method of this kind has extremely high expenditure with regard to the vacuum chambers required for this technology, and is also very difficult to integrate in a possible manufacturing cycle and moreover produces film layers which would have to be adapted by means of additional special coating systems for- the high mechanical demands on security documents.
In DE 4 126 051 Al again is. presented a security document with embedded planar security element (security thread) which is constructed in several layers and has electroluminescent properties. A drawback of this arrangement is that a relatively high surface construction has to be allowed for, because the electrodes required to stimulate the electroluminescent substances are arranged one on top of the other.
If a luminescent element which can be stimulated e.g. by UV light is provided in a security document, further authenticity features being applied, to this arrangement, then stimulation of the UV-sensitive layer located under
the authenticity feature can no longer take place. Up to now, therefore, it was not possible: to provide the known authenticity elements with . corresponding luminescent background illumination.
It is therefore the object of the invention to develop a value and security product of the kind mentioned hereinbefore in such a way that an authenticity element with background illumination is provided.
To achieve the set object the invention ,is characterised by the technical instruction of claim 1.
An essential feature of the invention is that below a layer constructed as an authenticity element is provided a luminescent arrangement in the form of a luminescent element which is preferably caused to light up by an electrical field or by an electron source. This luminescent element serves as background illumination for the authenticity element provided above it.
In this case there are various possibilities for the nature and construction of the. luminescent element, which are all encompassed by the concept of the present invention.
In a first preferred embodiment this background-illuminating layer is constructed as an electroluminescent layer. According to the invention, therefore, a-so-called electroluminescent system is used in which preferably an electrical field is built up laterally, i.e. in planar fashion, so that an advantage of this arrangement lies in that the whole construction on the substrate material wears out only a little.
In another embodiment of the invention it is however provided that the electrical field for stimulating the electroluminescent layer consists of planar electrodes which are arranged .one above the other, wherein the electroluminescent layer is then arranged between the electrodes.
For an electroluminescent plate capacitor construction (in which now according to the 'invention the two capacitor
"plates" essentially lie in a common plane) there, is needed
a transparent, electrically conductive layer which 'is achieved by means of so-called ITO pastes (indium-tin oxides). The same is moreover also achieved by precoated transparent films or glasses. Typically, biaxially oriented and thermally stabilised polyester films are used, coated with electrically conductive tin oxide or indium-tin oxide (ITO) applied by vapour deposition or sputter technology, or very generally transparent, electrically conductive, metallised surfaces with surface resistance values in the region of. a few ohms per square in the case of glass substrates and typically 20 ohms per square up to 300 ohms per square or more.
High-quality electroluminescent systems require a uniform luminance and a maximum light yield. Owing to the high thermal load carrying capacity during coating processes, glass substrates in general offer a higher-quality solution with higher light-transmitting capacity in the visible wavelength range, at the same time with better surface conductivity. The essential advantage of the ITO paste printing technique used according to the invention however lies in the relatively simple application and the graphic design potential which is almost anything desired, which can be advantageous particularly with more complex systems regarding the electrical connections.
As ITO screen printing pastes of this kind scarcely allow surface resistance values below 300-400 ohms per square, so-called bus bars which are edges which are good conductors of electricity are used with the invention. By this means uniform electrical fields are achieved and hence uniform luminance. Furthermore with this technique connection of the ITO electrode can be made functionally favourable and finally the ITO electrode layer thickness can be reduced in thickness to a minimum in favour of higher transparency. According to the invention bus bars are printed in printing technology by means of silver, carbon, copper, etc. pastes, or a combination of these
elements and hence surface resistance values in the region of several tens of milliohms per square are reached.
The invention includes different embodiments whose most important characteristics are summed up below:
The luminescent element has a lateral electrode assembly on the value and security product. The electrode assembly in lateral or opposed arrangement is located outside the security document, i.e. in a reader.
The lateral electrode assembly is located on a transparent covering substrate in the reader. An. electrically conductive coating on the rear side of the security document (before the graphic design process) and application of electroluminescent security elements to the front side and formation of a transparent covering substrate with electrically conductive coating on the side facing towards the security element.
Stimulation of the electroluminescent element by an alternating electromagnetic field.
Stimulation by a system on the basis of photoluminescent stimulation by means of appropriate light sources, in particular in the UV wavelength range, and use of suitable luminescent substances based mainly on Mn-activated silicates, phosphates, tungstates, germinates, borates, etc., but In particular on the basis of Zn2Si04:Mn and stimulation by the 253.65 nm line of a Hg low-pressure discharge lamp (visible light eliminated with short-pass filter) and stimulated emission of, light in the visible green range.
Stimulation of the luminescent system by an extremely narrow-band light source in the form of a frequency-tripled or frequency-quadrupled Nd:YAG laser with the wavelengths 266 nm and 213 nm, furthermore of a solid-state laser with corresponding frequency doubling or quadrupling, to 236 nm as .well as excimer laser with
light in the UV-B (320-260 nm according to USA FDA) or UV-C (260-200 nm) wavelength range for the stimulation of .special luminous substances - adjusted to the respective wavelength, wherein in addition luminous substances or so-called phosphor powders are added, similar to use in fluorescent tubes, so that radiation in the visible wavelength range is produced by this means and can be perceived by the human eye without further aids.
In an alternative embodiment, instead the stimulation is provided by IR radiation of suitable wavelength for materials with specific IR absorption and emission in the visible range. OVI pigments, (optically variable pigments) or liquid crystals can also be used in addition to the electroluminescent pigments or mixed in.
In a preferred embodiment the value and security product comprises security elements on the basis of so-called microencapsulated inorganic compounds of groups II and VI of the periodic system (e.g. ZnS, CdS) which are doped or activated with metals such as Cu, Mn, Ag and are suitable for print design by means of intaglio printing. Electroluminescent security elements . can also be constructed on the basis of organic polymers.
The electrodes are constructed laterally (that is,
located in planar fashion adjacent.to each other) by means
of conductive intaglio printing inks,. wherein in the
resulting field gap which is also arranged approximately in
planar fashion between the electrodes there is generated an
alternating electromagnetic field whose field lines at
least partially pass through the print image produced by
the electroluminescent substances and so cause the
electroluminescent security elements to light up and the
latter can thus be used visually and mechanically for
In a preferred embodiment an electrically conductive intaglio printing ink is used on the basis of carbon and/or
silver or a mixture of both or silver and/or gold-plated metal pigments or mica pigments in combination with suitable binders on the basis of polyurethanes and/or aliphatic polyesters and corresponding thinners, wherein: in particular the two electrode terminals are constructed in a non-oxidising surface form.
As the dielectric and insulating layer, preferably an aqueous polyurethane layer, is applied to the unprepared surface of the security document - e.,g. a banknote - before actual graphic design and then the phosphor paste is printed in order thus to achieve a good elastic adhesive bond with outstanding surface stability.
The luminescent security feature is in this case preferably graphically designed from individual dots and lines.
Furthermore correspondingly graphically designed transparent inks can be applied above/below/adjacent to the luminescent elements and hence different coloured luminous effects can be obtained.
According to the invention the electroluminescent layer described above is used as background illumination for an authenticity element. An authenticity element of this kind is e.g. a laser-capable polycarbonate film which. is also referred to below as a PC overlay film. A film of this kind can be provided with authenticity features e.g. by laser treatment in such a way that in a controlled and deliberate fashion in the thick region of this film cloudiness and/or staining can be applied, as a result of which then the background illumination arranged underneath this film accordingly radiates differently through these different zones of the authenticity element. In this way a characteristic authenticity feature can be visible on the visible side of the authenticity element such as e.g. a passport image, a logo, a coat of arms, a personalised signature or the like.
In a second embodiment of the present invention it ,is provided that in the layer of: the laser-capable overlay
film are formed bores or recesses which are preferably also produced by laser treatment. The invention is however not confined to this; recesses of this kind can also be made by etching processes, punching processes, stamping processes,
by electrode beam action, water jet treatment and the like.
It is important here that with the present invention first and foremost it is not the composition of the authenticity element that matters, but the fact that the authenticity element is assigned active background illumination which can be made to light up practically without highly elaborate equipment and without external equipment such as e.g. a UV lamp or a laser diode.
Similarly of course the authenticity features associated with the authenticity element can be introduced not just by laser treatment or by the other physical processes and treatment methods described above, but furthermore printing of this film can take place. In this case there are the most varied printing processes such as e.g. offset printing, screen printing, thermosublimation printing, intaglio printing as well as all non-impact printing processes.
With all the processes and applications described it is important that the authenticity element can be varied within relatively wide limits and different authenticity elements can be provided but that in each case background illumination can be associated with this authenticity element.
It was mentioned at the beginning that an electroluminescent substance is used as a preferred embodiment for this luminous background illumination.
In another embodiment of the present invention it is provided that a luminous substance is stimulated by an electron source. In this case there are various embodiments:
In a first embodiment it is provided that the electron source is arranged over the overlay film in front, so that the electrode radiation passes through the overlay, film and
stimulates the layer underneath which produces the background illumination.
In another embodiment it is provided that the electron source is arranged on the opposite side of the assembly, i.e. opposite the overlay film, so that the existing card is basically irradiated from the rear side.
For irradiation with an electron source there are again various possibilities which are all encompassed "by the present invention.
In a first embodiment it is provided that, there is used as the electron source a heated anode which in a manner known in the art emits an electrode field towards the luminous layer, a construction such as is known in anode technology being preferred.
In another embodiment it is provided that as the electron source there is provided an electrode beam which scans the whole luminous layer or parts thereof in lines and makes it light up.
In a third embodiment it is provided that a matrix-like electrode field is provided, which in pixel form causes the layer to light up in a controlled fashion.
Besides using an electron source naturally an X-ray
source or other radiation source can be used which is
suitable to stimulate accordingly the layer serving as the
background illumination. . «
Besides stimulation by corresponding high-energy particle radiation there are also other stimulation mechanisms which are encompassed by the present invention. There is so-called sonoluminescence which provides for stimulation by sound radiation, as well as triboluminescence which on stimulation by mechanical deformation, by friction or by destruction of the crystals also achieves stimulation of the luminous layer.
As far as it is a question of an electroluminescent substance which forms the background illumination, it is essentially a question of the stimulation of this electroluminescent layer taking place in the alternating
electromagnetic field, a planar electrode assembly being used preferably. A planar electrode; assembly of this kind consists of electrodes which interlock in finger fashion and which form between them a field gap, in which field gap is generated the alternating electrical field which stimulates the electroluminescent layer above or in between and makes it light up.
The electroluminescent, layer can in this case be applied directly to the electrodes and in another embodiment the electroluminescent layer can be separated by an insulating layer arranged between the lower side of the electroluminescent layer and the upper side of the electrode surface.
In the event that the electrode assembly is covered initially by an insulating layer on which is then arranged the electroluminescent layer,. it is preferred if the dielectric constant of this electroluminescent layer is selected as high as possible. This has the advantage that the field lines which form as leakage flux .between the electrodes enter the electroluminescent layer with hi'gh efficiency and make it light up.
In all cases it is a question of applying the alternating electromagnetic field to the card in a manner which is as simple and operationally reliable as possible. For this purpose according to the invention capacitive coupling is provided. This capacitive coupling takes place preferably by at least two electrode surfaces on the security document which are spaced apart and insulated from each other and which form one side of a plate capacitor The other, opposite side of the plate capacitor is formed from associated electrode surfaces of a reader.
It is an advantage of this arrangement that coupling of the alternating electromagnetic field takes place without contact.. Production of the luminescent element becomes very simple as a result, because the electrodes together with the field-generating electrode assembly (for field stimulation of the electroluminescent layer) can be
printed or applied in a single-operation
The reader which is responsible .for applying the alternating electromagnetic field to the electrode surface can be of particularly simple construction. In. this case it is sufficient to provide the reader with a corresponding battery, to provide an inverter/oscillator which then with its terminal assembly goes to an—associated electrode assembly, "which electrode assembly in turn is the above-mentioned one side of .the plate capacitor whose other side is the electrode assembly arranged on the,card.,
The advantage of the background illumination: according to the invention in connection with the ordinary reader lies in that security and value documents. can be checked -.in a particularly simple manner. Monitoring or checking :of this kind can also take, place at night because the background illumination ensures that the luminous authenticity element can be made to light up under all conditions.
Therefore in a single step there is both display -of the authenticity element, which does not necessarily have to be optically visible otherwise, and at the same time there is read-out of this authenticity element in one and the same operation.
Hence there is the advantage that even invisible
' ' •'
secondary security features can be made visible,in a simple manner.
Another advantage lies in that other features can also be associated with the authenticity element (the above-mentioned polycarbonate film), ie.g. in such a way that in the. laser-treated film in which corresponding recesses are formed, additional microlenses are placed on the.recesses. Such microlenses can of course be applied not just in a subsequent operation to the previously made recesses, but they can already be applied during the initial laser treatment of the overlay film by .appropriate treatment steps. Due to the arrangement of such microlenses there is an improvement in readability of the authenticity feature,
because the solid angle of readability is increased and angular dependence in examination - is decreased. Moreover there is also a general enlargement of the authenticity feature by the lens effect.
The microlenses are preferably introduced into the laser-treated film by a high-melting lamination process. Similarly corresponding polymers can be applied to the film by photopolymerisation. The overlay film can also be constructed as a holographically modulated photorefractive polymer layer.
As the preferred frequency for the alternating .electromagnetic field of the electroluminescent layer, frequency ranges in the region of approximately 1-10 kHz and voltages in the region of approximately 100-1500 V are preferred.
The subject of the present invention results not just from the subject of the individual patent claims, but also from the combination of the individual patent claims with each other. All the particulars and characteristics disclosed in the documents including the abstract, in particular the three-dimensional construction shown in the drawings, are claimed as essential to the invention insofar as they are new compared with the state of the art individually or in combination. .
Below, the invention is described in more detail with the aid of drawings which show only one embodiment. Here, further characteristics essential to the invention and advantages of the invention are apparent from the drawings and the description thereof. They show: Figure 1 top view of a value and security document
in a first embodiment of the invention,
with an associated reader; Figure 2 the side view of the arrangement according
to Figure 1; Figure 3 a schematised section through the value and
security document according to Figure 1
with the addition of further embodiments of
Figure 4 another section: through another embodiment of a value and security document.
In Figure 1 in general the reference number 1 denotes a value document which consists of a plastic substrate, a paper substrate or some other substrate material. Here it is irrelevant whether the document 1 is constructed with one or more layers.
To the value document 1 is applied an electrode assembly 2 consisting of a plurality of electrodes 2a, 2b which interlock in finger fashion and which form between them a meander-like field gap 3 in which the alternating electromagnetic field becomes operative.
To this electrode assembly 2 or. between the electrode assembly 2 is now applied or introduced an electroluminescent layer 13 which is at least partially penetrated by the alternating electrical field which is generated in the field gap 3.
The electrode assembly 2 is contacted by associated leads 4, 5 which are applied to the value document 1, which
" ' leads are connected in electrically conductive relationship to associated electrode surfaces 6, 7.
The alternating electromagnetic field is capacitively coupled to these electrode surfaces 6, 7, this being by an electrode assembly 9 of a reader 8 which comprises electrode surfaces which are opposite the electrode surfaces 6, 7 and which altogether form the electrode assembly 9 (Figure 2).
In the reader 8 in this case are arranged one or more current supplies, e.g. batteries 10, which are connected to an inverter/oscillator 11 which in turn is connected by a terminal assembly 12 to the electrode assembly 9 of the reader 8. •
Between the electrodes 6, 7 and the electrode assembly 9 of the reader 8 is thus formed a coupling surface 17 by which the alternating electromagnetic field is coupled to the electrode surface 6, 7.
Further details of the invention are apparent from the Figures 2-4. First it can be seen . in Figure 2 that above the electroluminescent layer 13 is arranged an overlay film 14 which can consist of different materials. Of course a polycarbonate film is preferred, but any other materials can be used, namely those which are suitable for carrying a corresponding authenticity feature in them, or on them, -or of forming it in them, wherein secondary coupling mechanisms can be used.
The above layer can even consist of a conductive metal foil which accordingly carries the authenticity feature. Such an authenticity feature can be .obtained e.g. by applying corresponding structures 15 to/in an overlay film 14. Such structures are, according to the general part of the description, introduced as cloudiness or staining into the structure of the overlay film 14 e.g. by laser treatment, X-ray treatment or electron beam treatment..
In another embodiment it is possible for such structures to be introduced as recesses 16, as shown on the right side in Figure 3. Recesses 16 of this kind would not necessarily have to be through-holes, but they can be blind holes or irregularly shaped openings, e.g. lozenge-shaped, square or rectangular openings.
Similarly of course type characters can: be formed directly from such recesses. In particular a digitalised signature can be formed as a type character by recesses of this kind.
In Figure 3 furthermore stimulation of the electroluminescent layer 13 by. an electron source 19 is shown. The electron source 19 -is here driven by a generator 18 and emits an electron cloud 21 by means of'a. focusing device 20 towards the value document 1. Here it is provided that the electrons pass in sufficient number through the overlay film and stimulate the electroluminescent layer 13 underneath to light up.
Naturally it is provided that the whole stimulating assembly can be arranged on the opposite side of Figure 3,
so that the electroluminescent layer 13 can also be
,\- ' •!'
stimulated from the lower side of the value document 1.
The production of an electron cloud 21 of this kind is known in the art and is not the subject of the present invention. It is only important that the electroluminescent layer is not only stimulated by ;an alternating electromagnetic field, - but also by other stimulating mechanisms which have already been described above.
Figure 4 further shows another' embodiment which is constructed similarly to Figure 3' (right side). The overlay film 14 is provided with recesses 16, lenses. 22 being applied to the recesses 16' in addition. The operation and manufacture of' these lenses have been described in detail in the general part of- the description.
Another embodiment of the 'invention .lies in that the electrode surface 6, 7 is used ;as a transponder coil or an additional transponder 'coil is inserted in order thus to allow inductive contactless coupling of the alternating electromagnetic field.
A construction of a value document of this kind is particularly preferred in the .application in transponder chip cards, because an additional authenticity feature which is particularly easy to read is.provided. .
It is of course possible to apply the electroluminescent layer not only as a separate,layer to the value document 1, but in the sense of DE 4 310 082 it is also possible to construct this electroluminescent layer as an electroluminescent film, wherein a corresponding electroluminescent-active pigment fraction is introduced into an extruded or coextruded film.
LEGEND OF DRAWINGS
1. value document
2. electrode assembly, 2a electrode, 2b electrode
3. field gap
6. electrode surface
7. electrode surface
9. electrode assembly ' (reader.)
12. terminal arrangement
13. electroluminescent layer
14. overlay film
17. coupling surface
19. electron source
20. focusing device
21. electron cloud
1. Value and security product with luminescent element,
consisting of a single-layer, or multi-layer substrate
material, wherein on or within one layer of this substrate
material is arranged at least one authenticity element,
characterised in that below the layer (14) constructed as
an authenticity element is provided a luminescent element
which is caused to light up by an electrical, optical or
mechanical energy source acting from the outside.
2. Value and security product according to claim 1,
characterised in that the luminescent element is
constructed as an electroluminescent element (2, 13).
3. Value, and security product according to either of claims
1 or 2, characterised in that the electroluminescent
element consists of a luminescent layer (13) arranged in
insulating fashion between an electrode assembly (2).
4. Value and,security product according to either of claims
1 or 2, characterised in that the electroluminescent
element consists of a planar electrode assembly (2) with
electrodes (2a, 2b) arranged adjacent to each other and .a
luminescent layer (13) mounted in insulating fashion on or
under the electrode assembly.
5. Value and security product according to any of claims 1
to 4, characterised in that at least one of the electrodes
consists of an electrically conductive and translucent tin
oxide or indium-tin oxide layer.
6. Value and security product according to any of claims 1
to 5, characterised in that the electrode assembly is
provided for stimulation of the luminescent layer outside
the security document in a suitable reader (8).
7. Value and security product according to any of claims 1
to 5, characterised, in that the electrode assembly is
provided for stimulation of the luminescent layer on a
transparent covering substrate in a reader (8).
8. Value and security product according to any of claims 1.
to 7, characterised in that the insulating layer exhibits
as high as possible a dielectric constant.
9. Value and security product.according to any of claims 1
to 8, characterised in that the connecting electrodes (4,
5; 6, 7) are made of electrically highly conductive metal
and/or carbon pastes.
10. Value and security product according to any of claims 1
to 9, characterised in that the electroluminescent element
(2, 13) is stimulated by a capacitively or inductively
coupled alternating electrical field.
11. Value and security product according to claim 1,
characterised in that the luminescent element is a
12. Value and security product according to either ,of
claims 1 or 11, characterised in that the photoluminescent
element is stimulated to light up - by electromagnetic
radiation sources of given wavelength(s).
13. Value and security product according to any of claims 1
to 12, characterised in .that the authenticity element
consists of a plastic film or metal, foil (14) applied to
the substrate material (1) and altered in its structure
(15) and/or colour.
14. Value and security product according to any of claims 1
to 13, characterised in that in the plastic film or metal
foil (14) are provided recesses and/or bores (16) of which
the authenticity features are composed.
15. Value and security product according to any of claims 1
to 14, characterised in that microlenses (22) are inserted on or in the recesses and/or bores (16).
16 Value and security, product according to any of claims; 1 to 15, characterised in that the authenticity .element has self-luminescent properties.
17. Value and security product according to any of claims 1 to 16, characterised in that the authenticity features are printed on the plastic film or metal foil .(14) .
18. Value and security product substantially as hereinbefore described with reference to the accompanying drawings.
|Indian Patent Application Number||2359/DEL/1998|
|PG Journal Number||38/2008|
|Date of Filing||12-Aug-1998|
|Name of Patentee||BUNDESDRUCKEREI GMBH|
|Applicant Address||ORANIENSTRASSE 91, D-10958, BERLIN, GERMANY.|
|PCT International Classification Number||B44F 1/12|
|PCT International Application Number||N/A|
|PCT International Filing date|