BACKGROUND OF THE INVENTION
1. Field of the invention
[0001] The present invention relates to electronic security means for security documents
such as banknotes, passports, chequebooks, etc, and more preferably to electronic
security means comprising display means (such as liquid crystals, or microencapsulated
electronic ink) to provide a visible display change when human skin contacts the secure
document.
2. Description of the Related Art
[0002] The use of self-authenticating security features for producing documents serves for
protecting them against unauthorized reproduction by forgers. This is necessary, in
particular, for securities such as banknotes, checks, traveller's checks, stocks,
etc. There is also a need for securing papers which do not have a direct monetary
value, such as identification papers, passports etc., against unauthorized copying.
[0003] In particular, in the case of securities, which are circulated daily, for example,
banknotes, a forger may succeed in copying the optically recorded document contents,
for example, the optical printed image of the banknotes, in a deceptively precise
way. A protection against this is the authenticity feature contained in the safety
paper, used for producing the documents, as a result of the structure imparted to
the safety paper during manufacture which authenticity feature supposedly practically
cannot be copied by a forger with the means available to him. Moreover, the application
of watermarks or the introduction of a safety thread into the paper is known. These
conventional measures, however, can no longer be considered satisfactory in view of
the advances of the working means employed by forgers. In particular, in the case
of global political crisis regions the war-conducting groups or even entire countries
employ forgery as warfare. Accordingly, the resources employed for forgery are correspondingly
great.
[0004] EP 1 431 062 suggests security documents comprising substrate means, on board-electrical power
supply means, such as photovoltaic cells, and electronic security means using said
on-board power supply means. However the security feature cannot be activated by the
user of the feature, if necessary. In addition a security feature of that kind is
limited by the capacity of the power supply means and/or the availability of the corresponding
power generating source.
[0005] CN 1 184 303 describes an anti-counterfeiting feature that consists of power source, controller
and driver circuit and panel display. The display is produced by means of semiconductor
technology and fine processing and is said to be difficult to counterfeit. However
the use of semiconductor technology and the necessity for a display controller and
driver circuit will limit the size, flexibility and durability of this device.
[0006] US 6 369 793 discloses a display system for magazines, advertising, toys, greeting cards, CD jackets,
etc. Said display system includes a printed display formed on a substrate that is
electrically connected to a printed battery, which is formed on the same substrate.
The display may be electrochromic, thermochromic, electroluminescent or electrophoretic.
The printed battery is a conventional wet electrochemical cell with an electrolyte-impermeable
separation layer between the anode layer and cathode layer. Once the separation layer
is removed the battery is activated, allowing for operation of the display. Conventional
touch pad switches may be introduced to allow the display to be switched on or off
after the cell has been activated.
[0007] The display system of
US 6 369 793 suffers from the use of a conventional electrochemical cell, which requires an encapsulated
wet electrolyte, leading to limitations in how thin the device could be manufactured
and limitations in the flexibility and durability of the device. The overall thickness
of this device is between approximately 125 microns and approximately 250 microns,
resulting in a device that is much thicker than what is acceptable for many secure
documents, especially banknotes.
[0008] Another drawback of a display system of this kind is its high rigidity and stiffness.
Repeatedly bending and folding of such a display system such as during the daily use
of a banknote would lead to a delamination of the multilayered anode / wet electrolyte
/ cathode structure and/or to the formation of cracks within one or more of said layers,
which in turn would result in a leakage of the electrochemical cell and a breakdown
of the cell.
[0009] In addition it has to be considered that conventional touch pad switches comprise
one or more mechanically moving parts, which make or break the connections in the
circuit upon activation. However the use of mechanically movable parts is not feasible
within security documents that are repeatedly bent and folded during daily use.
[0010] US 4,623,598 relates to a flat battery wherein a flat generating element is sealed and sheathed
with a sheathing film and both positive and negative terminals are installed on one
surface of either the upper or the lower portion thereof. The positive and negative
collectors are separated one from another, but electrically connected to each other
via an electrolyte, such as an electrolytic solution. The battery is comparatively
thin and has a high capacity per unit area. However,
US 4,623,598 does not mention any possible fields of application.
SUMMARY OF THE INVENTION
[0012] The main objective of the present invention is to provide a more flexible and reliable
overt security feature for secured documents that can be authenticated by a member
of the general public, and which has improved forgery-proof properties. In addition
the security feature shall be highly flexible, comparable small in thickness and highly
durable.
[0013] In carrying out these and other objects of the present invention, there is provided
a security document comprising substrate means and at least one electronic security
means, wherein said security document also comprises at least two contact points each
electrically connected to said electronic security means, but electrically isolated
from each other. Thereby a highly flexible and reliable overt security feature for
secured documents is made available that can be authenticated by a member of the general
public in a very simple way, and which has improved forgery-proof properties.
[0014] In particular, the security feature of the document can be activated by the user
making an electrical contact, such as a skin contact across the surfaces of at least
two contact points. This results in the generation and/or flow of small amounts of
electrical power that operate the electronic security means and display the security
feature.
[0015] In addition the present invention overcomes the size, flexibility and durability
limitations of conventional electro-optic displays, electrical power sources and electrical
interconnects. The security document of the present invention is extremely thin, since
the thickness of the power source and/or switch is only dictated by the size of the
contact points. In addition the security document of the present invention exhibits
a very high flexibility, and a very high durability, particularly in comparison with
display systems comprising conventional electrochemical cells containing an anode,
a cathode and a wet electrolyte and/or conventional touch pad switches having mechanically
movable parts.
[0016] Especially suitable variations of the security document of the present invention
are described in the dependent products claims.
[0017] The process claims describes particularly suitable methods for the manufacture of
the security document of the present invention and the use claims refer to particularly
favourable ways of using the security document of the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018]
FIG. 1 is a plan view illustrating a preferred embodiment of the security document
of the present invention.
FIG. 2 is a perspective view (with the thickness of the components greatly enhanced)
of a preferred embodiment of the security document of the present invention.
FIG. 3 is a plan view of a preferred embodiment of the security document of the present
invention activated by the moisture of human skin preferably acting as an electrolyte.
FIG. 4 is a plan view of a preferred embodiment of the security document of the present
invention showing an interdigitated array of the anode and cathode elements.
FIG. 5 is a plan view of a preferred embodiment of the security document of the present
invention in which four set of contact points, preferably four electrochemical cells
are activated simultaneously using fingertip contact from a single hand.
FIG. 6 is a cross-sectional view of an electrophoretic ink display as used in a preferred
embodiment of the present invention.
FIG. 7a and 7b are plan views of a preferred embodiment of the present invention in
two different active states, such that the electrophoretic display image is reversed
in one active state in comparison to the second active state.
FIG. 8a and 8b are plan views of a preferred embodiment of the present invention in
two different active states, such that the electrophoretic display image is reversed
in one active state in comparison to the second active state.
DETAILED DESCRIPTION OF THE INVENTION
[0019] The following is a detailed description of the present invention. It provides a security
document comprising substrate means and at least one electronic security means. The
term "security document", as used herein refers to all kind of documents that contain
at least one feature that can be used to prevent counterfeiting by providing authentication,
identification or classification of the document. In particular, they include banknotes,
passports, chequebooks, identity cards, credit cards and/or debit cards.
[0020] According to the present invention the security document also comprises at least
two contact points each electrically connected to said electronic security means,
but electrically isolated from each other. Thereby the term "electrical connection"
refers to a connection via a material preferably having a resistivity ρ of less than
10
6 Ω · cm, very preferably of less than 10
-2 Ω · cm, when measured at 25°C. By the way of contrast two articles will be "electrically
isolated one from another" if there is no electrical connection between said articles,
in particular via a material having a resistivity ρ of less than 10
6 Ω · cm, when measured at 25°C.
[0021] The security document of the present invention is preferably adapted for checking
its authenticity by electrically connecting the contact points and observing a status
change of said electronic security means. Accordingly the surface of the contact points
is preferably exposed for electrical contact so that said contact points can be electrically
connected to each other by connecting the surfaces of said contact points via an electrically
conductive material, preferably via a material having a resistivity ρ of less than
10
6 Ω · cm, very preferably of less than 10
-2 Ω · cm, when measured at 25°C.
[0022] Furthermore at least two contact points are preferably located next to each other
with a separation of 0.01 cm to 1.00 cm between said contact points to allow an electrical
connection via a fingertip.
[0023] The positions of the contact points on the security document can principally be chosen
freely. It is merely important that the contact points are electrically isolated from
each other and that an electrical connection can be achieved by connecting the contact
points via an electrically conductive material. However it is of particular advantage
that at least two contact points are provided on the same side of said security document
in order to facilitate the application of the electrically conductive material and
in particular to allow the formation of an electrical connection via one single finger.
[0024] In another especially preferred embodiment of the present invention at least one
contact point is located on the front of the security document and at least one contact
point is located on the back of the security document, preferably in close proximity
one to another to allow the formation of an electrical connection via a electrically
conductive clamp, such as the thumb and the index finger of a human hand.
[0025] According to a further preferred embodiment of the invention a plurality of sets
each comprising at least two contact points are located on the substrate wherein the
sets are electrically connected in a series configuration or electrically connected
in a parallel configuration, or a combination of both series and parallel configurations.
A member of the general public may then use the fingertips of one or more hands to
simultaneously activate a plurality of sets. A series configuration of cells will
provide a higher voltage whereas a parallel configuration of cells will allow the
cells to operate a display with a higher current demand.
[0026] Therefore in one especially preferred embodiment the security document comprises
at least two sets comprising at least two contact points and at least one electronic
security means, wherein in each set said contact points are each electrically connected
to said electronic security means, but wherein in each set said contact points are
electrically isolated from each other (parallel configuration). Thereby at least one
set preferably comprises at least anode and at least one cathode having a different
electrochemical potential.
[0027] In another especially preferred embodiment comprises at least four contact points,
wherein the first contact point and the fourth contact point are each electrically
connected to said electronic security means, but electrically isolated from each other,
and wherein the second contact point is electrically connected to the third contact
point, but electrically isolated from the first and the fourth contact point (series
configuration). Thereby at least two contact points preferably have a different electrochemical
potential (anode and cathode).
[0028] In principle there are no particular restrictions on the material of the contact
points used in the present invention. However, the contact points preferably comprise
an electrically conductive material preferably having a resistivity ρ of less than
10
6 Ω · cm, very preferably of less than 10
-2 Ω · cm, when measured at 25°C.
Furthermore it is preferred that they comprise metals within the galvanic series of
metals. In addition, the contact points preferably comprise at least one conductive
polymer. Further information regarding the material of the contact points can be found
in the technical literature, such as Falbe et al. "Römpp-Lexikon Chemie" 10. Auflage,
Stuttgart, New York, Thieme 1997, keyword "Galvanische Elemente" (galvanic cells),
"elektrisch leitfähige Polymere" (electrically conductive polymers) and the references
cited therein.
[0029] The surfaces of the contact points are preferably left exposed to the environment.
In such circumstances, it will be apparent to those skilled in the art that materials
will be preferably chosen that suffer minimal tarnishing or corrosion during everyday
use of the secure document.
[0030] In another preferred embodiment, a very thin layer of solid polymer electrolyte is
deposited separately onto the contact points (i.e. the electrolyte does not connect
both contact points) such that the materials are protected from the environment. A
polymer electrolyte is preferred, as this will not detrimentally impact the desired
flexibility of the invention. The ionic conductivity of the solid polymer electrolyte
need only be very low, that is, equivalent or better than the ionic conductivity of
human skin. Polymer electrolytes consist of salts dissolved in polymers (for example,
polyethylene oxide, PEO). For good ionic conductivity these polymer electrolytes are
usually prepared in an amorphous state and contain mobile ionic species such as lithium
ions or silver ions. In these cases conductivities can be of the order of 10
-3 S/m. Since these conductivities are much higher than that exhibited by human skin,
these solid polymer electrolyte coatings do not impede the operation of this invention.
As will be understood by those skilled in the art, various contact point materials
and various suitable solid electrolyte coatings are possible, and these are considered
to be covered by this invention.
[0031] In the present invention the contact points are each electrically connected to the
electronic security means, preferably via one or more electrically conducting tracks.
Thereby the electrically conducting tracks can be made of any electrically conducting
material, but preferably have a resistivity ρ of less than 10
6 Ω · cm, very preferably of less than 10
-2 Ω · cm, when measured at 25°C. The use of copper tracks has proven of particular
advantage.
[0032] According to a first especially preferred embodiment of the present invention at
least two contact points have the same electrochemical potential, preferably when
measured at 25°C. Very preferably they are made of the same material. The contact
points of this kind form a switch. The circuit can be made by electrically connecting
said contact points via an electrically conductive material, such as human skin. On
the other hand the circuit will be broken upon removal of said electrically conductive
material.
[0033] The security document of this particular embodiment preferably comprises one or more
power generating means, and in particular at least one battery and/or at least one
photovoltaic cell. Further information regarding the power generating means can be
found in the technical literature, such as Falbe et al. "Römpp-Lexikon Chemie" 10.
Auflage, Stuttgart, New York, Thieme 1997, keyword "Batterien" (batteries), "Solarzellen"
(solar cells) and the references cited therein.
[0034] A particular preferred arrangement of this embodiment comprises at least two sets
of contact points and power generating means, wherein each set preferably comprises
at least two contact points.
[0035] In a second especially preferred embodiment of the present invention at least two
contact points of the security document have a different electrochemical potential,
preferably when measured at 25°C. Accordingly the security document of this embodiment
comprises at least one anode and at least one cathode each electrically connected
to said electronic security means, but electrically isolated from each other, i. e.
the electronic security means is connected to an electrochemical cell comprising at
least positive pole active material (cathode) and at least one negative pole active
material (anode) but missing an electrolyte electrically connecting said anode and
said cathode.
[0036] Every electrochemical cell requires an electrolyte to close the electrical circuit
for provision of electrical power, but it does not necessarily have to be encapsulated
within the cell. The electrolyte can be provided to the cell when operation is required
and fully removed after operation to once again leave dry anode and cathode materials
that do not interact or degrade. For extremely low electrical current requirements,
such as the present invention, this electrolyte may be in the form of the moisture
(e.g. sweat) contained at the surface of human skin.
[0037] This type of cell has the advantage of having no chemical electrolyte. It is - in
effect - simply two electrodes before it is touched, and in reality cannot be classed
as a cell in this state. There are no problems with chemical disposal, electrolyte
dry out or leakage. It can be realised in many shapes and sizes, with many different
configurations. It is extremely lightweight and exhibits a very low profile, with
a total material thickness of only 10 µm or less being required for operation.
[0038] In a particularly preferred arrangement of this embodiment a simple electrochemical
system based on the zinc-copper galvanic couple in a saline solution is appropriate
for the intended application, with zinc as the anode material and copper as the cathode
material. This is a simple galvanic system that is normally used in laboratories to
demonstrate the concept of electricity; it is not widely used in commercial applications
because of the low energy, power and working voltage, which it generates. However,
because of the extremely low current, power and energy requirements of the electronic
security means preferably used in the present invention, such as electrophoretic displays,
a thin electrochemical cell based on this electrochemical couple is suitable as a
power source for the electronic security means.
[0039] In a second particular preferred arrangement of the present embodiment the cathode
comprises MnO
2, preferably together with carbon black to increase the conductivity of the cathode.
The anode preferably comprises zinc.
[0040] In a third particular preferred arrangement of the present embodiment the cathode
comprises nickel oxyhydroxide and the anode comprises zinc.
[0041] In a fourth particular preferred arrangement of the present embodiment the cathode
comprises nickel oxyhydroxide and the anode comprises iron.
[0042] The actual shape of the contact points is not critical and can be square, rectangular,
round or oval in shape, for example. However, the use of an interdigitated design
of the contact points, preferably at least one anode and at least one cathode has
proven of particular advantage.
[0043] The electronic security means of the security document is not particularly limited
and can be any known in the art. However, it is particular advantageous that the security
means is an overt security feature, when activated. The term "overt feature", as used
herein refers to a feature can be simply verified by a member of the general public
using just the feature itself, and with no requirement for additional apparatus. Features
in which the feature can only be read by special machine apparatus are so-called "covert
features" which are not preferred for the purposes of the present invention.
[0044] In addition the electronic security means is preferably a low power display means
having an electric power consumption of preferably 10
-5 W or less. For example, if the moisture content within human skin is used as an electrolyte
for an electrochemical cell, the power source will have a high internal impedance
that is of the order of 10
5 to 10
6 Ω. The electrical current that can be drawn from the power source is consequently
very low and is of the order of 10
-5 to 10
-6 A. The potential voltage of the power source is dependent on both the nature of the
anode and cathode materials used in the electrochemical cell, and the number of cells
connected electrically in series with each other. For the particular embodiment of
invention that uses the copper-zinc galvanic cell, the potential voltage can range
from approximately 0.3 V for a single cell to approximately 1.6 V for four cells in
series activated by a single user.
[0045] Particularly suitable electronic security means for the purposes of the present invention
include electrophoretic ink display means and/or liquid crystal display means.
[0046] The kind of the substrate means used in the present invention is not critical. However
the use of substrate means comprising paper, plastic, polymer, elemental metallic
foils, metallic alloy foils and/or synthetic paper is preferred.
[0047] The security document of the present invention is comparatively thin and its thickness
is preferably smaller than 100 µm. In one especially preferred embodiment, the overall
thickness of the contact points, preferably at least one anode and at least one cathode,
not including the substrate thickness, is between approximately 10 to 50 µm. The thickness
of the interconnects between the power source and the display is preferably within
the range from approximately 1 to 30 µm. The thickness of the electronic security
means, not including the substrate means, depends on the kind of security means actually
used, but is preferably in the range from 25 to 300 µm.
[0048] Methods for the production of a security document of the present invention are obvious
to the skilled person. The substrate means is preferably provided with the contact
points, in particular the anode and the cathode, and the electronic security means,
wherein all components, including the electronic security means, may be printed onto
a common substrate. Alternatively, for substrates that are not compatible with the
manufacturing techniques required for the electronic security means, the power source
and interconnects may be printed onto the substrate whereas the complete display assembly
may be subsequently attached to the substrate. In this latter case, electrical connection
will be made by ensuring that exposed printed contact pads on the substrate align
with contact pads on the electronic security means.
[0049] In a specific embodiment of the present invention the conducting tracks and/or the
contact points, in particular the anode and the cathode, are deposited onto the substrate
using an electroless deposition technique. In this technique a specially formulated
catalytic ink is printed onto the substrate in a desired pattern. The substrate is
then immersed in a chemical solution containing ions of the metal to be deposited.
Over time, electroless deposition of the metal onto the substrate areas printed with
catalytic ink occurs. This technique is advantageous compared to other methods for
producing the desired electrically conducting tracks and the contact points, such
as printing of metal-loaded inks, since the technique produces deposited material
with a density that is very close to that of the bulk material. Furthermore, this
technique is advantageous over standard printing of loaded inks in that the adhesion
of the deposited material to the substrate is superior. The - aforementioned electroless
deposition technique is described in detail in Patent Application
WO 02/099163 and is suitable for a range of substrates (such as polyester, polypropylene, synthetic
paper, fine-weave cloths and polycarbonate) and a range of deposited metals (including
copper, nickel, cobalt, iron, tin and a variety of magnetic and non-magnetic alloys).
However, the present invention does not preclude other methods of depositing electrically
conducting materials and/or anodic or cathodic active materials. Other methods include
printing (such as screen printing and gravure printing) of particle-loaded inks, electroplating
methods, chemical vapour deposition, sputtering and etch-resist methods, all of which
are known to those skilled in the art.
[0050] For checking authenticity of the security document of the present invention the contact
points, preferably the anode and the cathode, are electrically connected to each other
by connecting the surfaces of said contact points via an electrically conductive material
preferably having a resistivity ρ of less than 10
6 Ω · cm, very preferably of less than 10
-2 Ω · cm, when measured at 25°C and a status change of said electronic security means
is observed. Thereby an electrolyte is preferably used. The electronic security means
is activated by said addition of an electrically conductive material to the security
document. In this invention the electrically conductive material is required to only
have a very low level of ionic conductivity, since for electrophoretic-type displays,
such as microencapsulated electrophoretic inks or electrophoretic liquid crystal-type
displays, only a very low level of electrical current is required for operation of
the display. In fact, it has been discovered that the transport properties of the
surface of human skin is sufficient to meet the required ionic conductivity- even
'dry' skin is sufficient - for operation of electronic security means, in particular
of electrophoretic displays. Accordingly the use of an electrolyte comprising water,
preferably of saline solution and/or the moisture of human skin is particular favourable.
[0051] In an especially preferred embodiment of the present invention the activation is
achieved by the moisture of human skin, such that when the skin contact is removed
from the contact point surfaces the security document immediately reverts back into
a non-activated state. Other forms of electrolyte, liquid or otherwise, such as moisture-containing
sponges or electrolytic gel, may be introduced to the contact points to switch the
security document from a non-active state to an active state, and subsequently removed,
by for example wiping dry, to switch the security document back to a non-active state,
and these are contemplated as falling within the scope of the present invention.
[0052] Referring now to the figures, several preferred embodiment of the invention each
comprising a dry electrochemical cell will be discussed. FIG. 1 is a plan view of
a first particular embodiment of the present invention. The cathode material 2 and
the anode material 3 are preferably printed on the substrate 1 and make up the dry
electrochemical cell. Electronic security means 6, preferably a display, which may
be by way of example an electrophoretic liquid crystal display or a microencapsulated
electrophoretic ink display, is either printed or, in a separate process, adhered
to the substrate means 1. The cathode material 2 and the anode material 3 are electrically
connected via electrically conducting interconnecting tracks 4 and 5 preferably printed
on the substrate means 1 to the electronic security means 6. There is no electrolyte
between the cathode 2 and the anode 3 and there is no direct electrical connection
between cathode 2 and anode 3 except via the electrophoretic display 6. As such, FIG.
1 is a view of a preferred embodiment of the present invention in a non-active state.
[0053] In a specific embodiment of the present invention, shown in FIG. 2 in perspective
view with the thickness of the deposited components greatly enhanced for clarity,
the electrically conducting tracks 4 and 5 are preferably formed from copper and are
preferably deposited using the electroless deposition technique. The electrically
conducting tracks may be printed before or after the display 6 is printed onto the
substrate or attached to the substrate, but in each case electrical connection is
made to the electronic security means. Alternatively, and potentially leading to a
more robust security document, the electrode conducting tracks are deposited during
appropriate steps of the manufacture of the display, as will be explained hereafter.
The cathode material 2 is preferably formed from copper and is preferably also deposited
using the electroless deposition technique. This may be deposited simultaneously with
deposition of the electrically conducting tracks.
[0054] The thickness of the deposited copper using this deposition technique is preferably
about 5 µm, which is deemed suitable for the present invention although electroplating
techniques may be used to further increase the thickness of the copper on the conducting
tracks and cathode as required. In this specific embodiment a thin layer of copper
7 is preferably also deposited, using the electroless deposition technique, at the
anode location and this may be deposited simultaneously with deposition of the conducting
tracks and the cathode. Zinc material 3 is then deposited on top of this first copper
layer at the anode location preferably by screen printing using an ink with solid
loading by volume of zinc between 40% and 60%. Fine conducting powder material may
be added to this ink, such as carbon black powder, to increase the conductivity of
the zinc loaded ink. It is understood that any method of printing may be used to deposit
such a solid loaded ink. In this particular embodiment the thickness of the conducting
tracks is of the order of 5 µm, the thickness of the cathode element is about 5 µm
and the thickness of the zinc material is approximately 15 µm.
[0055] In a further embodiment of the present invention the zinc anode is deposited by electroplating
on top of the copper layer 7 at the anode location 3; during this electroplating process
all other copper regions are preferably masked to prevent deposition of zinc elsewhere.
Alternative anode materials may be deposited on top of the copper layer. In a similar
manner, a different cathode material, that is, for instance, more positively active
within the galvanic series than copper (such as silver), may be deposited at the cathode
location, and such embellishments are considered to be covered by the present invention.
[0056] Other electrically conducting materials may be used for the interconnections between
the galvanic cell and the display, and other anode and cathode materials may be used,
metallic or otherwise, as will be familiar to those skilled in the art of electrochemical
cell design.
[0057] In a preferred embodiment of the invention the moisture contained within the human
skin is used as the electrolyte. Referring to FIG. 3, biologically active human skin
(i. e. human skin comprising at least some water, such as the skin of a living human
being), in the form of the inner surface of a thumb or finger 8 of a member of the
general public, is pressed over the surfaces of the cathode 2 and the anode 3. In
this situation the invention is said to be in an active state. The moisture content
of human skin acts as an electrolyte for the cell such that the cell generates an
electric potential and allows a very small amount of electric current to flow. With
specific design of the cell and careful choice of the display the generated potential
and current is sufficient to operate the electronic security means. The moisture content
and the salinity of human skin can vary greatly from person to person, even before
environmental and physical conditions have been considered. For direct current (dc)
conductivity and low frequencies the electrical impedance of human skin is dominated
by the outermost (stratum corneum) layer of the epidermis layer of skin. The thickness
of this layer can vary between 10 µm and 1 mm according to the amount of protection
and/or grip required by a region of the body. For example, the hands are typically
used to grasp objects, requiring the palms to be covered with a thick stratum corneum
(about 200 µm thick). Similarly, the sole of the foot is prone to injury, and so it
is protected with a very thick stratum corneum layer (about 1 mm thick). This stratum
corneum layer can act as a solid state electrolyte with only a few free ions required
for dc conductance. The cells of the stratum corneum layer can absorb water and this
has a marked effect on the electrical conductivity of human skin. The electrical conductivity
of human skin, at a frequency of measurement of 1 Hertz, can vary between about 10
-7 S/m for dry skin to about 10
-5 S/m for wet skin; and a typical resistance value as measured between two contact
points is ~10
5 Ω cm
2.
[0058] For a particular preferred embodiment using copper as the cathode material and zinc
as the anode material, the electric potential generated by the cell through the use
of skin moisture as an electrolyte can be predicted from the galvanic series of metals
in saline solution to be approximately 0.6 V to 0.7 V. The potential generated into
a Digital Voltmeter with an internal impedance of 10
6 Ω for this embodiment of the invention is about 0.5 V upon pressing a dry finger
across the copper and zinc samples. The internal resistance of this activated cell
is estimated to be about 0.4 Megaohms. Consequently, the cell has a high internal
resistance and is only suitable for operating devices that present a much higher resistance
to the cell, and that require very small electrical current for their operation. For
this reason, electrophoretic displays, which are capacitive in nature and have a very
high dc resistance, are particularly suitable for direct operation from these skin-activated
galvanic cells. It will be apparent to those skilled in the art that other display
types may be compatible with such power sources, and these are hence contemplated
as falling within the scope of the present invention. Improving electrolyte salinity
and moisture content will reduce the internal resistance of the cell, thus improving
its current-sourcing capability.
[0059] In a further embodiment of the invention the anode and cathode materials are deposited
in an interdigitated pattern as shown in FIG. 4. The fingers of the comb array of
the anode 9 fit between the fingers of the comb array of the cathode 10. Any number
of fingers may be used and the separation between anode and cathode may be of any
distance but is limited by the resolution of the various printing and deposition methods
mentioned earlier. This arrangement has the advantage that the activated cell (that
is, when pressing human skin across the interdigitated array) has a lower internal
resistance and will thus be able to produce more current into a given load, when compared
to the embodiment shown in FIG. 1. Many other geometrical arrangements of the anode
and cathode are possible and these are considered to be covered by this invention.
[0060] For a number of electrophoretic display types (as will be discussed later), a higher
potential voltage than that provided by the simple galvanic cell previously described
is required to operate the display. Higher voltages may be achieved, to some extent,
by changing the nature of the anode and cathode to more negatively active and more
positively active materials, respectively. However, another option is to arrange the
cells electrically in series, as shown in plan view in FIG. 5. In this particular
embodiment of the invention four of the galvanic cells are arranged electrically in
series such that the negative pole (preferably a zinc anode) of one cell is in electrical
contact with the positive pole of the next cell (preferably a copper cathode).
[0061] In practice, in order for the voltage potentials from series cells to sum up, the
cells should not share the same electrolyte, as is the case for this particular embodiment
of the invention. However, human skin exhibits a relatively large impedance between
two points (e.g. two fingers, or two hands). This, coupled with the fact that a display
with extremely high impedance is connected to the cells, allows the cells to be connected
in series whilst effectively sharing the same electrolyte. The impedance of the skin
between fingertips separates the electrolytes with an impedance that is greater than
each individual cell impedance, and therefore does not shunt the cell. In this particular
embodiment, the four cells connected in series, simultaneously activated by four fingertips
from one hand, provide a potential difference of 1.6V. This is higher than that provided
by a single cell but, as expected, does not quite equal the sum of the potential provided
by four individually operated cells.
[0062] In a particular preferred embodiment of the present invention, a printed electrophoretic
display 11, shown in cross-section view in FIG. 6, may be used as the display 6 in
the self-authenticating feature. The display comprises a substrate 12 which may also
be the same as the substrate means 1. An electrode layer 13 is then formed on the
substrate layer. This bottom electrode layer may be printed, using for example a silver
ink, or deposited using the electroless deposition technique previously described
and as referred to in Patent Application
WO 02/099163. The bottom electrode layer may be printed simultaneously with one of the electrical
tracks (4 or 5) and in this manner connection between the dry electrochemical cell
and the display is facilitated. Other methods of forming the electrode layer will
also be apparent to those skilled in the art, and these are contemplated as falling
within the scope of this invention. An electrophoretic layer 14 is then formed on
top of the electrode layer by printing for example, although other deposition methods
are considered to be covered by the present invention. A suitable electrophoretic
layer would be composed of, for example, electronic ink. The electronic ink can constitute
micro-encapsulated charged particles within an ink carrier. Moreover, the electronic
ink may be composed of any suspension of electrically charged or electrically polarisable
pigment particles contained in a fluid or ink carrier, and this is contemplated as
falling within the scope of the present invention. Finally, a transparent electrode
layer 15 is formed over the electrophoretic layer. Preferably the transparent electrode
material is indium tin oxide (ITO) although other transparent conductive materials
may be used and are contemplated as falling within the scope of the present invention.
The transparent electrode layer may be deposited by means of a vacuum-deposition or
sputtering process, but preferably, for the present invention, ITO inks are deposited
using a printing process (as per
US Pat. No. 5421926). Printing of the top electrode layer 15 may be undertaken simultaneously with printing
of the remaining electrical track (5 or 4) such that electrical connection to the
electrochemical cell is facilitated. When a voltage with a first polarity is applied
across the electrodes 13 and 15 an electric field is generated within the electrophoretic
layer 14. The electric field exerts a force on the pigment particles, which move towards
the transparent electrode, thus producing the colour of the pigment to the viewer
16. When a voltage with opposite polarity is applied to the electrodes 13 and 15,
the pigment particles are attracted to the bottom electrode such that the colour of
the ink dye is observed. It is preferable that the particles are light with high scattering
coefficients (as is the case for titanium dioxide) in a dark-dyed ink medium. Since
the display behaves electrically as a capacitor, only a small amount of power is required
for operation of the display. Because the display is capacitive in nature, and the
fact that the display change relies on the movement of particles within a fluid medium,
there is a finite time taken for the display to change state that is dependent upon
the potential voltage applied to the display. It is found that for observation of
a colour change from such a display within a reasonable time period (<20 seconds)
the required applied potential voltage was about 1 volt. Lower voltages may be achieved
by reducing the separation between the electrodes 13 and 15 since this will give rise
to a higher electric field within the electrophoretic layer. Additional information
regarding electrophoretic displays using electronic inks can be found in US Pat. No.
5604027,
US Pat. No. 5872552,
US Pat. No. 6323989,
US Pat No. 6480182 and
US Pat. No. 6665042.
[0063] In a particular embodiment of the present invention, shown in FIG. 7a, two adjacent
electrophoretic displays 17 and 18 and four dry electrochemical cells are configured
such that when two of the electrochemical cells are activated (when the user presses
fingertips across each of the cells simultaneously, and the remaining two electrochemical
cells are in the non-active state) one display 17 is provided with a negative polarity
and the other adjacent display 18 with a positive polarity. This has the effect of
making one display appear black and the other appear white, thereby enhancing the
contrast to the viewer. In FIG. 7a the electrical track 19 is connected to the bottom
electrode 12 of the electrophoretic display that is common to both display 17 and
display 18. The electrical track 20 is connected to the top electrode 15 of electrophoretic
display 17 and electrical track 21 is connected to the top electrode 15 of electrophoretic
display 18. Thus in FIG. 7a the bottom two electrochemical cells are activated such
that the left half of the electrophoretic display is black whilst the right half of
the electrophoretic display is white. The top two cells of this particular embodiment
are reversed in polarity such that when these are activated (and the bottom two cells
are in the non-active state), as shown in FIG. 7b, image in the display reverses such
that the left half of the electrophoretic display is white whilst the right half of
the electrophoretic display is black
[0064] In actual fact the connection to the bottom electrode of this electrophoretic display
is not required, since the potential applied to the top electrodes of the electrophoretic
displays will always be referenced against the common bottom electrode of displays
17 and 18. As such the same effect may be observed by the configurations shown in
FIG. 8a and 8b: the electrical track 22 is connected to the top electrode 15 of electrophoretic
display 17 and the electrical track 23 is connected to the top electrode 15 of electrophoretic
display 18. A plurality of cells with different polarities could be considered, each
connected to different elements within the electrophoretic display and this is considered
to be covered by the present invention. Each electrochemical cell could be activated,
by making skin contact across the anode and cathode elements of each cell, individually
or in combinations that are designed to give rise to a particular display feature.
In this way, the complexity of the feature is enhanced to provide a feature that is
more difficult to counterfeit.
[0065] It will be apparent to those skilled in the art that the voltages and low currents
generated by the skin-activated electrochemical cells may be used to operate other
types of displays. By way of example, liquid crystal-based displays are also electrophoretic
in that the application of a voltage to the display creates an electric field, which
causes rotation or other movement of molecules or particles within the display. As
such, liquid crystal displays require very low electrical currents and may be suitable
for operation with the high impedance, skin-activated electrochemical cells described
in this invention. By way of further example, only a very low level of electrical
current, of the order of ten microamps, is required to illuminate a single pixel of
a polymer-based light emitting diode, and these may therefore also be suitable for
operation with the skin-activated electrochemical cells. The operation of other display
types using these skin-activated electrochemical cells is contemplated as falling
within the scope of the present invention.
[0066] In principle, the specific arrangements shown can also be used when the contact points
have the same electrochemical potential, and preferably are made of the same material.
In order to operate the electronic security means the security document preferably
also comprises power-generating means and/or power-generating means are preferably
connected to the security document when making the electrical contact between the
contact points. The use of power-generating means located on the security document
is particularly preferred.
1. Security document comprising substrate means and at least one electronic security
means, wherein the security document also comprises at least two contact points each
electrically connected to said electronic security means, but electrically isolated
from each other, characterized in that the contact points comprise an electrically conductive material and in that at least two contact points have a different electrochemical potential.
2. Security document according to claim 1, characterized in that said security document is a banknote, a passport, a chequebook, an identity card,
a credit card or a debit card.
3. Security document according to claim 1 or 2, characterized in that the security document is adapted for checking its authenticity by electrically connecting
the contact points and observing a status change of said electronic security means.
4. Security document according to at least one of the preceding claims, characterized in that at least two contact points are located next to each other with a separation of 0.01
cm to 1.00 cm between said contact points.
5. Security document according to at least one of the preceding claims, characterized in that said contact points can be electrically connected to each other by connecting the
surfaces of said contact points via an electrically conductive material.
6. Security document according to at least one of the preceding claims, characterized in that at least two contact points are located on the same side of said security document.
7. Security document according to at least one of the claims 1 to 5, characterized in that at least one contact point is located on the front of the security document and at
least one contact point is located on the back of the security document.
8. Security document according to at least one of the preceding claims, characterized in that said security document comprises at least two sets comprising at least two contact
points and at least one electronic security means, wherein in each set said contact
points are each electrically connected to said electronic security means, but wherein
in each set said contact points are electrically isolated from each other.
9. Security document according to at least one of the preceding claims, characterized in that said security document comprises at least four contact points, wherein the first
contact point and the fourth contact point are each electrically connected to said
electronic security means, but electrically isolated from each other, and wherein
the second contact point is electrically connected to the third contact point, but
electrically isolated from the first and the fourth contact point.
10. Security document according to at least one of the preceding claims, characterized in that the contact points comprise an electrically conductive material.
11. Security document according to claim 11, characterized in that said contact points comprise metals within the galvanic series of metals.
12. Security document according to claim 10 or 11, characterized in that said contact points comprise at least one electrically conductive polymer.
13. Security document according to at least one of the preceding claims, characterized in that at least one contact point comprises an electrolyte coating.
14. Security document according to at least one of the preceding claims, characterized in that contact points exhibit resistance to oxidation and/or tarnishing from exposure to
the atmospheric environment.
15. Security document according to at least one of the preceding claims, characterized in that said security document comprises electrically conducting tracks connecting said anode
and said cathode to said electronic security means.
16. Security document according to at least one of the claim 10 to 15, characterized in that at least two contact points have the same electrochemical potential.
17. Security document according to claim 16, characterized in that the security document comprises power-generating means.
18. Security document according to claim 17, characterized in that said security document comprises a battery or a photovoltaic cell.
19. Security document according to claim 16 or 17, wherein the security document comprises
at least two sets of contact points and power-generating means.
20. Security document according to at least one of the claim 10 to 15, characterized in that at least two contact points have a different electrochemical potential.
21. Security document according to at least one of the preceding claims, characterized in that said electronic security means is an overt security feature.
22. Security document according to at least one of the preceding claims, characterized in that said electronic security means is a low power display means.
23. Security document according to claim 22, characterized in that said low power display means are electrophoretic ink display means and/or liquid
crystal display means.
24. Security document according to at least one of the preceding claims, characterized in that said substrate means comprises paper, plastic, polymer, elemental metallic foils,
metallic alloy foils and/or synthetic paper.
25. Security document according to at least one of the preceding claims, characterized in that its thickness is smaller than 100 µm.
26. Method for the production of a security document according to at least one of the
preceding claims, wherein said contact points and said electronic security means are
provided on said substrate means.
27. Method according to claim 26, characterized in that said contact points are printed onto said substrate means.
28. Method according to claim 26 or 27, characterized in that said contact points are deposited onto said substrate means by using electroless
deposition, sputtering and/or vacuum deposition.
29. Method according to at least one of the claims 26 to 28, characterized in that electrically conducting tracks are deposited onto said substrate means by the use
of electroless deposition, sputtering and/or vacuum deposition.
30. Method according to at least one of the claims 26 to 29, characterized in that electrically conducting tracks are printed onto said substrate means by the use of
conductive inks.
31. Method according to at least one of the claims 26 to 30, characterized in that said contact points and electrically conducting tracks are provided simultaneously.
32. Method according to at least one of the claims 26 to 31, characterized in that said electronic security means is provided before or after the provision of said
contact points.
33. Method according to at least one of the claims 17 to 23, characterized in that said electronic security means and/or said contact points are provided on both sides
of said security document.
34. Use of a security document according to at least one of the claims 1 to 25 for checking
its authenticity, wherein said contact points are electrically connected to each other
by connecting the surfaces of said contact points via an electrically conductive material
and a status change of said electronic security means is observed.
35. Use according to claim 34, characterized in that an electrolyte is used as said electrically conductive material.
36. Use according to claim 35, characterized in that said electrolyte comprises water.
37. Use according to claim 36, characterized in that said electrolyte comprises moisture of human skin.
1. Sicherheitsdokument, umfassend Substratmittel und mindestens ein elektronisches Sicherheitsmittel,
wobei das Sicherheitsdokument auch mindestens zwei Kontaktpunkte umfasst, die jeweils
elektrisch mit dem elektronischen Sicherheitsmittel verbunden sind, aber voneinander
elektrisch isoliert sind, dadurch gekennzeichnet, dass die Kontaktpunkte ein elektrisch leitendes Material umfassen und mindestens zwei
Kontaktpunkte ein unterschiedliches elektrochemisches Potential haben.
2. Sicherheitsdokument gemäß Anspruch 1, dadurch gekennzeichnet, dass das Sicherheitsdokument ein Geldschein, ein Pass, ein Scheckheft, ein Ausweis, eine
Kreditkarte oder eine Debitkarte ist.
3. Sicherheitsdokument gemäß Anspruch 1 oder 2, dadurch gekennzeichnet, dass das Sicherheitsdokument dafür geeignet ist, dass man seine Authentizität überprüft,
indem man die Kontaktpunkte elektrisch verbindet und eine Zustandsänderung des elektronischen
Sicherheitsmittels beobachtet.
4. Sicherheitsdokument gemäß mindestens einem der vorangehenden Ansprüche,
dadurch gekennzeichnet, dass mindestens zwei Kontaktpunkte mit einer Entfernung von 0,01 cm bis 1,00 cm zwischen
den Kontaktpunkten nebeneinander angeordnet sind.
5. Sicherheitsdokument gemäß mindestens einem der vorangehenden Ansprüche,
dadurch gekennzeichnet, dass die Kontaktpunkte elektrisch miteinander verbunden werden können, indem man die Oberflächen
der Kontaktpunkte mittels eines elektrisch leitenden Materials verbindet.
6. Sicherheitsdokument gemäß mindestens einem der vorangehenden Ansprüche,
dadurch gekennzeichnet, dass mindestens zwei Kontaktpunkte auf derselben Seite des Sicherheitsdokuments angeordnet
sind.
7. Sicherheitsdokument gemäß mindestens einem der Ansprüche 1 bis 5, dadurch gekennzeichnet, dass mindestens ein Kontaktpunkt auf der Vorderseite des Sicherheitsdokuments angeordnet
ist und mindestens ein Kontaktpunkt auf der Rückseite des Sicherheitsdokuments angeordnet
ist.
8. Sicherheitsdokument gemäß mindestens einem der vorangehenden Ansprüche,
dadurch gekennzeichnet, dass das Sicherheitsdokument mindestens zwei Sätze umfasst, die mindestens zwei Kontaktpunkte
und mindestens ein elektronisches Sicherheitsmittel umfassen, wobei bei jedem Satz
die Kontaktpunkte jeweils elektrisch mit dem elektronischen Sicherheitsmittel verbunden
sind, wobei aber bei jedem Satz die Kontaktpunkte voneinander elektrisch isoliert
sind.
9. Sicherheitsdokument gemäß mindestens einem der vorangehenden Ansprüche,
dadurch gekennzeichnet, dass das Sicherheitsdokument mindestens vier Kontaktpunkte umfasst, wobei der erste Kontaktpunkt
und der vierte Kontaktpunkt jeweils mit dem elektronischen Sicherheitsmittel verbunden
sind, aber voneinander elektrisch isoliert sind und wobei der zweite Kontaktpunkt
mit dem dritten Kontaktpunkt elektrisch verbunden ist, aber vom ersten Kontaktpunkt
und vom vierten Kontaktpunkt elektrisch isoliert ist.
10. Sicherheitsdokument gemäß mindestens einem der vorangehenden Ansprüche,
dadurch gekennzeichnet, dass die Kontaktpunkte an elektrisch leitendes Material umfassen.
11. Sicherheitsdokument gemäß Anspruch 10, dadurch gekennzeichnet, dass die Kontaktpunkte Metalle innerhalb der galvanischen Reihe der Metalle umfassen.
12. Sicherheitsdokument gemäß Anspruch 10 oder 11, dadurch gekennzeichnet, dass die Kontaktpunkte mindestens ein elektrisch leitendes Polymer umfassen.
13. Sicherheitsdokument gemäß mindestens einem der vorangehenden Ansprüche,
dadurch gekennzeichnet, dass mindestens ein Kontaktpunkt eine Elektrolytbeschichtung umfasst.
14. Sicherheitsdokument gemäß mindestens einem der vorangehenden Ansprüche,
dadurch gekennzeichnet, dass die Kontaktpunkte Beständigkeit gegen Oxidation und/oder Trübung aufgrund einer Raumklimaeinwirkung
aufweisen.
15. Sicherheitsdokument gemäß mindestens einem der vorangehenden Ansprüche,
dadurch gekennzeichnet, dass das Sicherheitsdokument elektrisch leitende Bahnen umfasst, die die Anode und die
Kathode mit dem elektronischen Sicherheitsmittel verbinden.
16. Sicherheitsdokument gemäß mindestens einem der Ansprüche 10 bis 15, dadurch gekennzeichnet, dass mindestens zwei Kontaktpunkte das gleiche elektrochemische Potential haben.
17. Sicherheitsdokument gemäß Anspruch 16, dadurch gekennzeichnet, dass das Sicherheitsdokument stromerzeugende Mittel umfasst.
18. Sicherheitsdokument gemäß Anspruch 17, dadurch gekennzeichnet, dass das Sicherheitsmittel eine Batterie oder eine photovoltaische Zelle umfasst.
19. Sicherheitsdokument gemäß Anspruch 16 oder 17, dadurch gekennzeichnet, dass das Sicherheitsdokument mindestens zwei Sätze von Kontaktpunkten und stromerzeugenden
Mitteln umfasst.
20. Sicherheitsdokument gemäß mindestens einem der Ansprüche 10 bis 15, dadurch gekennzeichnet, dass mindestens zwei Kontaktpunkte ein unterschiedliches elektrochemisches Potential haben.
21. Sicherheitsdokument gemäß mindestens einem der vorangehenden Ansprüche,
dadurch gekennzeichnet, dass das elektronische Sicherheitsmittel ein offenkundiges Sicherheitsmerkmal ist.
22. Sicherheitsdokument gemäß mindestens einem der vorangehenden Ansprüche,
dadurch gekennzeichnet, dass das elektronische Sicherheitsmerkmal ein Schwachstrom-Anzeigemittel ist.
23. Sicherheitsdokument gemäß Anspruch 22, dadurch gekennzeichnet, dass das Schwachstrom-Anzeigemittel ein elektrophoretisches Anzeigemittel und/oder ein
flüssigkristallines Anzeigemittel ist.
24. Sicherheitsdokument gemäß mindestens einem der vorangehenden Ansprüche,
dadurch gekennzeichnet, dass das Substratmittel Papier, Kunststoff, Polymer, elementare, metallische Folien, metallische
Legierungsfolien und/oder synthetisches Papier umfasst.
25. Sicherheitsdokument gemäß mindestens einem der vorangehenden Ansprüche,
dadurch gekennzeichnet, dass seine Dicke kleiner als 100 µm ist.
26. Verfahren zur Herstellung eines Sicherheitsdokuments gemäß mindestens einem der vorangehenden
Ansprüche, wobei man die Kontaktpunkte und das elektronische Sicherheitsmittel auf
dem Substratmittel bereitstellt.
27. Verfahren gemäß Anspruch 26, dadurch gekennzeichnet, dass man die Kontaktpunkte auf das Substratmittel druckt.
28. Verfahren gemäß Anspruch 26 oder 27, dadurch gekennzeichnet, dass man die Kontaktpunkte auf dem Substratmittel unter Verwendung von stromloser Abscheidung,
Bedampfung und/oder Vakuumabscheidung abscheidet.
29. Verfahren gemäß mindestens einem der Ansprüche 26 bis 28, dadurch gekennzeichnet, dass man elektrisch leitende Bahnen auf dem Substratmittel unter Verwendung von stromloser
Abscheidung, Bedampfung und/oder Vakuumabscheidung abscheidet.
30. Verfahren gemäß mindestens einem der Ansprüche 26 bis 29, dadurch gekennzeichnet, dass man elektrisch leitende Bahnen auf das Substratmittel unter Verwendung von leitfähiger
Tinte druckt.
31. Verfahren gemäß mindestens einem der Ansprüche 26 bis 30, dadurch gekennzeichnet, dass man die Kontaktpunkte und die elektrisch leitenden Bahnen gleichzeitig bereitstellt.
32. Verfahren gemäß mindestens einem der Ansprüche 26 bis 31, dadurch gekennzeichnet, dass man das elektronische Sicherheitsmittel vor oder nach der Bereitstellung der Kontaktpunkte
bereitstellt.
33. Verfahren gemäß mindestens einem der Ansprüche 17 bis 23, dadurch gekennzeichnet, dass man das elektronische Sicherheitsmittel und/oder die Kontaktpunkte auf beiden Seiten
des Sicherheitsdokuments bereitstellt.
34. Verwendung eines Sicherheitsdokuments gemäß mindestens einem der Ansprüche 1 bis 25
zur Überprüfung seiner Authentizität, wobei man die Kontaktpunkte elektrisch miteinander
verbindet, indem man die Oberflächen der Kontaktpunkte mittels eines elektrisch leitenden
Materials verbindet, und eine Zustandsänderung des elektronischen Sicherheitsmittels
beobachtet.
35. Verwendung gemäß Anspruch 34, dadurch gekennzeichnet, dass man ein Elektrolyt als elektrisch leitenden Material verwendet.
36. Verwendung gemäß Anspruch 35, dadurch gekennzeichnet, dass das Elektrolyt Wasser umfasst.
37. Verwendung gemäß Anspruch 36, dadurch gekennzeichnet, dass das Elektrolyt Feuchtigkeit der menschlichen Haut umfasst.
1. Document de sécurité comprenant des moyens de substrat et au moins un moyen de sécurité
électronique, dans lequel le document de sécurité comprend également au moins deux
points de contact, chacun connecté électriquement audit moyen de sécurité électronique,
mais isolés électriquement l'un de l'autre, caractérisé en ce que les points de contact comprennent un matériau électro-conducteur et en ce qu'au moins deux points de contact ont un potentiel électrochimique différent.
2. Document de sécurité selon la revendication 1, caractérisé en ce que ledit document de sécurité est un billet de banque, un passeport, un carnet de chèque,
une carte d'identité, une carte de crédit ou une carte de débit.
3. Document de sécurité selon la revendication 1 ou 2, caractérisé en ce que le document de sécurité est adapté pour contrôler son authenticité en connectant
électriquement les points de contact et en observant un changement d'état dudit moyen
de sécurité électronique.
4. Document de sécurité selon au moins une des revendications précédentes, caractérisé en ce qu'au moins deux points de contact sont situés près l'un de l'autre avec une séparation
de 0,01 cm à 1,00 cm entre lesdits points de contact.
5. Document de sécurité selon au moins une des revendications précédentes, caractérisé en ce que lesdits points de contact peuvent être connectés électriquement entre eux en connectant
les surfaces desdits points de contact via un matériau électro-conducteur.
6. Document de sécurité selon au moins une des revendications précédentes, caractérisé en ce qu'au moins deux points de contact sont situés sur le même côté dudit document de sécurité.
7. Document de sécurité selon au moins une des revendications 1 à 5, caractérisé en ce qu'au moins un point de contact est situé sur l'avant du document de sécurité et au moins
un point de contact est situé sur l'arrière du document de sécurité.
8. Document de sécurité selon au moins une des revendications précédentes, caractérisé en ce que ledit document de sécurité comprend au moins deux ensembles comprenant au moins deux
points de contact et au moins un moyen de sécurité électronique, dans lequel chaque
ensemble desdits points de contact est connecté électriquement audit moyen de sécurité
électronique, mais dans lequel chaque ensemble desdits points de contact est isolé
électriquement l'un de l'autre.
9. Document de sécurité selon au moins une des revendications précédentes, caractérisé en ce que ledit document de sécurité comprend au moins quatre points de contact, dans lequel
le premier point de contact et le quatrième point de contact sont chacun connectés
électriquement audit moyen de sécurité électronique, mais isolés électriquement l'un
de l'autre, et dans lequel le deuxième point de contact est connecté électriquement
au troisième point de contact, mais isolé électriquement du premier et du quatrième
point de contact.
10. Document de sécurité selon au moins une des revendications précédentes, caractérisé en ce que les points de contact comprennent un matériau électro-conducteur.
11. Document de sécurité selon la revendication 11, caractérisé en ce que lesdits points de contact comprennent des métaux dans la série galvanique des métaux.
12. Document de sécurité selon la revendication 10 ou 11, caractérisé en ce que lesdits points de contact comprennent au moins un polymère électro-conducteur.
13. Document de sécurité selon au moins une des revendications précédentes, caractérisé en ce qu'au moins un point de contact comprend un revêtement d'électrolyte.
14. Document de sécurité selon au moins une des revendications précédentes, caractérisé en ce que des points de contact présentent une résistance à l'oxydation et/ou au ternissement
découlant de l'exposition à l'environnement atmosphérique.
15. Document de sécurité selon au moins une des revendications précédentes, caractérisé en ce que ledit document de sécurité comprend des pistes électriquement conductrices connectant
ladite anode et ladite cathode audit moyen de sécurité électronique.
16. Document de sécurité selon au moins une des revendications 10 à 15, caractérisé en ce qu'au moins deux points de contact ont le même potentiel électrochimique.
17. Document de sécurité selon la revendication 16, caractérisé en ce que le document de sécurité comprend des moyens de génération d'énergie électrique.
18. Document de sécurité selon la revendication 17, caractérisé en ce que ledit moyen de sécurité électronique comprend une batterie ou une pile photovoltaïque.
19. Document de sécurité selon la revendication 16 ou 17, dans lequel le document de sécurité
comprend au moins deux ensembles de points de contact et de moyens de génération d'énergie
électrique.
20. Document de sécurité selon au moins une des revendications 10 à 15, caractérisé en ce qu'au moins deux points de contact ont un potentiel électrochimique différent.
21. Document de sécurité selon au moins une des revendications précédentes, caractérisé en ce que ledit moyen de sécurité électronique est une caractéristique de sécurité manifeste.
22. Document de sécurité selon au moins une des revendications précédentes, caractérisé en ce que ledit moyen de sécurité électronique est un moyen d' affichage à faible puissance.
23. Document de sécurité selon la revendication 22, caractérisé en ce que ledit moyen d'affichage à faible puissance est un moyen d'affichage à encre électrophorétique
et/ou un moyen d'affichage à cristaux liquides.
24. Document de sécurité selon au moins une des revendications précédentes, caractérisé en ce que lesdits moyens de substrat comprennent du papier, plastique, polymère, des feuilles
métalliques élémentaires, des feuilles d'alliage métallique et/ou du papier synthétique.
25. Document de sécurité selon au moins une des revendications précédentes, caractérisé en ce que son épaisseur est inférieure à 100 µm.
26. Procédé pour la production d'un document de sécurité selon au moins une des revendications
précédentes, dans lequel lesdits points de contact et ledit moyen de sécurité électronique
sont disposés sur lesdits moyens de substrat.
27. Procédé selon la revendication 26, caractérisé en ce que lesdits points de contact sont imprimés sur lesdits moyens de substrat.
28. Procédé selon la revendication 26 ou 27, caractérisé en ce que lesdits points de contact sont déposés sur lesdits moyens de substrat en utilisant
un dépôt autocatalytique, pulvérisation et/ou dépôt sous vide.
29. Procédé selon au moins une des revendications 26 à 28, caractérisé en ce que des pistes électriquement conductrices sont déposées sur lesdits moyens de substrat
en utilisant un dépôt autocatalytique, pulvérisation et/ou dépôt sous vide.
30. Procédé selon au moins une des revendications 26 à 29, caractérisé en ce que des pistes électriquement conductrices sont imprimées sur lesdits moyens de substrat
en utilisant des encres conductrices.
31. Procédé selon au moins une des revendications 26 à 30, caractérisé en ce que lesdits points de contact et pistes électriquement conductrices sont disposés simultanément.
32. Procédé selon au moins une des revendications 26 à 31, caractérisé en ce que ledit moyen de sécurité électronique est disposé après ou avant la disposition desdits
points de contact.
33. Procédé selon au moins une des revendications 17 à 23, caractérisé en ce que ledit moyen de sécurité électronique et/ou lesdits points de contact sont disposés
sur les deux côtés dudit document de sécurité.
34. Utilisation d'un document de sécurité selon au moins une des revendications 1 à 25
pour contrôler son authenticité, dans laquelle lesdits points de contact sont connectés
électriquement entre eux en connectant les surfaces desdits points de contact via
un matériau électro-conducteur et un changement d'état dudit moyen de sécurité électronique
est observé.
35. Utilisation selon la revendication 34, caractérisée en ce qu'un électrolyte est utilisé comme ledit matériau électro-conducteur.
36. Utilisation selon la revendication 35, caractérisée en ce que ledit électrolyte comprend de l'eau.
37. Utilisation selon la revendication 36, caractérisée en ce que ledit électrolyte comprend l'humidité de la peau humaine.