Classifications

• • G—PHYSICS
  • G07—CHECKING-DEVICES
  • G07D—HANDLING OF COINS OR VALUABLE PAPERS, e.g. TESTING, SORTING BY DENOMINATIONS, COUNTING, DISPENSING, CHANGING OR DEPOSITING
  • G07D7/00—Testing specially adapted to determine the identity or genuineness of valuable papers or for segregating those which are unacceptable, e.g. banknotes that are alien to a currency
  • G07D7/06—Testing specially adapted to determine the identity or genuineness of valuable papers or for segregating those which are unacceptable, e.g. banknotes that are alien to a currency using wave or particle radiation
  • G07D7/12—Visible light, infrared or ultraviolet radiation
  • G07D7/121—Apparatus characterised by sensor details
• • G—PHYSICS
  • G07—CHECKING-DEVICES
  • G07D—HANDLING OF COINS OR VALUABLE PAPERS, e.g. TESTING, SORTING BY DENOMINATIONS, COUNTING, DISPENSING, CHANGING OR DEPOSITING
  • G07D7/00—Testing specially adapted to determine the identity or genuineness of valuable papers or for segregating those which are unacceptable, e.g. banknotes that are alien to a currency
  • G07D7/06—Testing specially adapted to determine the identity or genuineness of valuable papers or for segregating those which are unacceptable, e.g. banknotes that are alien to a currency using wave or particle radiation
  • G07D7/12—Visible light, infrared or ultraviolet radiation
  • G07D7/1205—Testing spectral properties

Definitions

• the present invention relates to a device and a method for visualizing security elements present in an object which have at least one photoluminescent segment which is characterized by linearly polarized photoluminescence and / or linearly polarized absorption.
• Such a security element is such.
• B. has been described in WO 00/19016.
• security papers and security articles in general, for example banknotes, checks, shares, bonds, ID cards, Passports, driver's licenses, entrance tickets, stamps and similar documents or, for example, for bank cards, credit cards and similar security elements are used which have the purpose of preventing or complicating the forgery of these objects by unauthorized persons (R. van Renesse, Optical Document Security "(1997 ), Artech House, Boston), such security elements are used to identify the authenticity or validity of objects or more generally to enable or facilitate the identification of objects.
• security threads or strips which may consist, for example, of a plastic coated with metal, in security papers, in particular for use in banknotes and similar securities, is widespread. If these security threads or strips are embedded in the security paper, for example, and this is then possibly printed, these security elements cannot be easily recognized if the object is viewed in reflection. However, they appear as a dark shadow when the object is illuminated and is thus observed in transmission.
• WO 00/19016 in which a security paper or quite generally security articles are described which contain at least one security element which has at least one photoluminescent segment which is characterized by linearly polarized photoluminescence and / or linearly polarized absorption.
• linearly polarized excitation light which is generated, for example, by an external light source i. V. m. a linear polarizer can be generated, absorbed by the segment depending on the orientation of the polarization axis of the segment and the polarization direction of the excitation light, which can lead to a strong light / dark contrast when viewed by the naked eye.
• the invention is therefore based on the object of providing a method or a device for visualizing security elements present in an object, the security elements to be observed having at least one photoluminescent segment which is characterized by linearly polarized photoluminescence and / or linearly polarized absorption is.
• the device is intended to be easy and reliable to recognize of the security elements without having to resort to a complicated and possibly fragile construction.
• At least one light source and at least one polarization filter are arranged in such a way that the light of the light source is linearly polarized by a polarization filter, strikes the object or the photoluminescent segments present therein, and the segment transmits photoluminescent light a further and / or the same polarization filter can be observed.
• the essence of the invention consists in passing both the incident light and the light that is photoluminescent from the segment through a polarization filter.
• the contrast of the observation is increased in a surprisingly simple manner, and interference signals which usually occur as a result of scattered light or as a result of dirty polarization can be suppressed efficiently.
• the security elements have linearly polarized photoluminescence and linearly polarized absorption, and if both irradiation and observation take place through the same polarization filter.
• This arrangement is particularly simple and efficient, since in this case the contrast can be particularly increased and only one polarization filter is required, which is used for both light paths and which has a polarizing effect in both spectral ranges (excitation and photoluminescence).
• the at least one light source emits light in the UV range, and the light that is photoluminescent from the at least one segment is in the visible range.
• Such segments are not visible to the naked eye under normal conditions and have a particularly high level of security with regard to counterfeiting. In particular for such security features, there is a need for specific and simple devices for verification.
• the light source is preferably a UV light source with an emission in the range from 180 to 500 nanometers, typically in the range from 200 up to 400 nanometers.
• the original light source does not have to be limited to this frequency range, but it can also be a broadband light source, in front of which a corresponding bandpass filter is arranged, so that only UV light hits the object, in particular in the range mentioned.
• this bandpass filter in such a way that it also acts as a polarization filter at the same time.
• the arrangement of 2 filters can be avoided.
• the light source can be a mercury vapor lamp, a laser light source or a halogen lamp or an arc discharge lamp.
• the device is designed such that the observation takes place through a filter which essentially does not allow light in the wavelength range of the light source to pass, while light in the wavelength range of the light photoluminescent from the segment can pass essentially unhindered.
• a filter which essentially does not allow light in the wavelength range of the light source to pass, while light in the wavelength range of the light photoluminescent from the segment can pass essentially unhindered.
• an additional filter should be used for the observation, which has essentially no transmission in the UV range, while it is transparent for the visible range. In this way, stray light from the light sources (direct stray light or reflected stray light from housing parts or from the object with the security feature) can be efficiently suppressed and the verification of the security features improved or improved. be simplified.
• Another preferred embodiment is characterized in that the incident light and the light that is photoluminescent from the segment pass through the same polarization filter and that the polarization filter can be rotated for observation about an axis perpendicular to the plane of the polarization filter, in particular with the aid of a motor.
• the rotation of the polarization filter leads to an intense light / dark effect of the segments (light if the polarization directions are parallel, dark if the polarization directions are perpendicular to one another) during the observation, which makes the security features in relation to the environment particularly prominent.
• the rotation of the polarization filter can be easily realized technically by the polarization filter being encased in a mounting ring, the polarization filter being rotated via a drive belt running around the mounting ring and driven by a motor driven drive wheel, and particularly preferably the mounting ring being tangentially connected via at least three engaging guide rollers is rotatably mounted.
• a round polarization filter can be used, in which the radiation then occurs to a certain extent from the side, obliquely from above, through several light sources through the polarization filter, and the reflected light can be observed vertically upwards through the central region of the polarization filter. This simple observation through the center of the polarization filter is not possible if the polarization filter is rotatably supported about a central axis.
• a further preferred embodiment is characterized in that only one of the polarization directions (polarization direction of the incident light or polarization direction of the filter between object and observation) is rotated.
• a first polarization filter is arranged between the light source and the object, and in that a second polarization filter is arranged between the object and the observation, and in that either the first or the second polarization filter rotates about an axis perpendicular to the plane of the polarization filter, in particular with the aid of a motor can be turned while the other polarization filter is not rotated.
• This arrangement leads to a particularly pronounced flip-flop effect.
• Another preferred embodiment is characterized in that the change in the polarization direction of the incident light is not brought about by a mechanical rotation of one (or more) polarization filter, but by different light sources which throw light of different polarization direction onto the object.
• This embodiment can be realized by at least 2 Light sources are arranged in that a polarization filter is provided in front of each of the light sources, the polarization directions of the light beams falling on the object from the different light sources being different, and the different light sources being successively actuated in an alternating manner.
• the rotation of the polarization filter when irradiated onto the object can thus be simulated by, to a certain extent, stroboscopically alternately irradiating different polarization directions from different lamps. This can be combined with a rotating polarization filter between object and observation, or with a fixed polarization filter between object and observation.
• any number of different light sources each with differently oriented polarization filters, can be arranged and these can be controlled successively.
• the mechanical rotation can be adjusted as precisely as desired.
• such a device can be implemented in a particularly simple manner using few light sources and with a pronounced flip-flop effect by arranging 2 light sources (or 2 groups of similar light sources, where each group can also contain more than one light source), and by the polarization directions of the light rays falling on the object from the 2 light sources are shifted by 90 degrees, the 2 light sources being able to be switched on and off in an alternating manner, preferably with a frequency in the range from 0.2 to 5 Hz, particularly preferably with a frequency of 0.5 to 2 Hz.
• a camera particularly preferably a CCD color camera
• a display particularly preferably a TFT-LCD color display.
• suitable image processing such as contrast adjustment, color adjustment, brightness adjustment, ner magnification and / or resolution adjustment
• a display particularly preferably a TFT-LCD color display.
• the camera can also preferably be a multi-chip camera, in particular a three-chip camera.
• the resolution and thus the quality of the verification of the security feature can be increased by such high-quality camera types.
• the light source is a UV lamp, preferably a UV tube with a wavelength in the range from approx. 200 to approx. 390 nanometers, particularly preferably with a wavelength in the range from approx 350 to approximately 370 nanometers (each the maxima of the emission bands), and that the polarization filter is a broadband linear polarizer, which particularly preferably has a polarizing effect in a wavelength range from 300 to 770 nanometers.
• the light source is a UV lamp, preferably a UV tube with a wavelength in the range from approx. 200 to approx. 390 nanometers, particularly preferably with a wavelength in the range from approx 350 to approximately 370 nanometers (each the maxima of the emission bands)
• the polarization filter is a broadband linear polarizer, which particularly preferably has a polarizing effect in a wavelength range from 300 to 770 nanometers.
• the polarization filter is a broadband linear polarizer, which particularly preferably has a polarizing effect in a wavelength range
• the polarization filter has a linearly polarizing effect both in the excitation area and in the observation area
• this filter should either have a broadband characteristic, or at least be transparent and polarizing in the observation area and in the area of the irradiated UV line. It is important to adapt the characteristics of the UV tube to the characteristics of the polarization filter (or vice versa), i.e. H. Care must be taken to ensure that the polarization filter produces an efficient linear polarization both in the area of observation (e.g. in the visible range) and in the UV range of the irradiation and that losses in these spectral ranges are kept low.
• a further improvement of the device according to the invention can be obtained by additionally equipping the device to verify other additional security features.
• the other security features can be magnetic, electrical, optical, electronic, electro-optical features, for example selected from the group barcodes, magnetic strips, conductivity, electroluminescence, photoluminescence, up-conversion (anti-Stokes), infrared signatures, electronically readable texts ( OCR writing) also trade with infrared writing, X-ray fluorescence features etc.
• the present invention relates to a method for visualizing security elements present in an object, which have at least one photoluminescent segment which is characterized by linearly polarized photoluminescence and / or linearly polarized absorption, which method is characterized in that light from at least one light source is linearly polarized by at least one polarization filter, strikes the object or the photoluminescent segments present therein, and photoluminescent light from the segment is observed through a further and / or the same polarization filter, a device as described above being particularly preferred place.
• FIG. 1 a) a perspective view from above of a hand-held device with an electronic display; b) a central section perpendicular to the main axis of a hand-held device according to FIG. la); c) a side view of a hand-held device according to FIG. la); d) a view from below of the upper housing part according to A-A in Fig. lc); e) a view from above of the lower housing part according to B-B in Fig. lc); and
• Fig. 2 shows a section according to Fig. Lb) through a handheld device without electronic Display.
• FIG. 1 a shows a perspective view of a hand-held device 20 with an electronic display, which is intended to serve as the first exemplary embodiment of the present invention.
• the hand-held device 20 has an upper housing part 8 and a lower housing part 10 which are screwed onto one another and which both have an oval cross section.
• a TFT-LCD color display 7 is arranged on the upper side 18, on which the object 4 to be examined is imaged.
• the handheld device 20 has handle notches 19 at the end of the main axis (the ellipse) halfway up, which make the device easier to handle.
• ventilation slots 12 are arranged immediately below these notches 19 in order to allow the heat generated in the device to escape.
• the device has a height of 13.5 cm, a length along the main axis of 23.3 cm and a width along the secondary axis of 15.4 cm. The total weight is less than 10 kg.
• the device has two switches 11 on the upper side 18, one of which is provided for switching on the lamps and the other switch for switching on the motor for rotating the polarization filter 2.
• the device has three rotary controls 13 in the upper area of the long side. These rotary controls 13 allow the brightness, the contrast and the color sensitivity of the display 7 to be adjusted as required.
• the 'longitudinal side connectors 14, 15 and 16 are also provided in the region. One of these connection sockets serves as a connector 14 for an external display. In other words, the output of the CCD camera 6 arranged inside can be led to another display via this connection socket.
• two connections 15 and 16 are provided, one of which is used to connect a battery charger. The energy supply of the device in autonomous operation is ensured by batteries arranged in the interior of the housing, which can be charged via this connection 16.
• the second connector 15 can be used to connect an external 12 volt supply, if either the batteries are empty or a stationary operation is generally intended.
• Fig. Lb shows a central section along the minor axis of the ellipsoidal device, which is to serve as a schematic representation of the operation.
• the device has two UV lamps 1, which are arranged parallel to the main axis and laterally in the upper part 8 of the housing. These are lamps whose emission characteristics have a maximum in the range from 365 to 370 nm (UVA, for example mercury vapor lamps with a corresponding Phosphor coating or UV LEDs).
• UVA for example mercury vapor lamps with a corresponding Phosphor coating or UV LEDs.
• the light 24 emanating from these lamps passes through a centrally arranged polarization filter 2 in order to then strike the object 4 to be examined with a security feature as linearly polarized light 23.
• Security features can be observed which have a photoluminescence from the UV range into the visible range and in which either absorption and / or emission are linearly polarized. It can be a wide variety of objects, such as. B. banknotes, certificates, tickets, access authorizations, stamps, ID cards, packaging, identity cards, passports, etc., generally around documents whose counterfeit security should be ensured by appropriate photoluminescence security features with polarizing properties.
• Object 4 is covered for viewing by the device. covered, and observed through a dedicated hole 27 in the bottom.
• the lower housing part has a dark space 22 about 5.5 cm high above the hole 27, which is sealed off from the interior 21 in the upper housing part 8 by a cover glass 3.
• the cover glass 3 is intended to prevent the cavity 21, in which optical and electronic devices are located, from being contaminated.
• the mostly likewise polarized light 25 emitted by the object 4 in the visible range, which light can have a wide variety of colors according to the security features, then passes upwards through the same polarization filter 2 onto a CCD camera 6.
• This CCD camera 6 also has a filter 5 , which eliminates electromagnetic radiation in the frequency range of the light sources 1 from the light entering the camera.
• the CCD camera is a UV filter which emits direct light from UV lamps 1, UV scattered light, or from Parts of the housing or the object 4 reflected UV light does not enter the CCD camera 6.
• the CCD camera is connected to a TFT-LCD color display 7 on which the security features of the object 4 are shown.
• the data determined by the CCD camera 6 can, if necessary, be subjected to an adapted image processing which makes the security features stand out.
• the polarization filter 2 can be rotated in this device for observation. This means that a characteristic light / dark effect can be observed when observing.
• the light / dark effect comes about because when the polarization direction of the polarization filter 2 and the polarization direction of the polarizing segment of the security feature are aligned parallel to one another, a bright reflection appears on the display, while no reflection can be observed in the case of orthogonal alignment. Observation through the same polarization filter leads to an increased visibility of this light / dark effect, since this automatically ensures optimal coordination or adaptation of the polarization direction of radiation and observation.
• the polarization filter is a broadband polarization filter, i. H. a carrier that efficiently polarizes light in the range of approximately 300 to approximately 770 nanometers.
• Fig. Lc) shows a side view of the device. It can be seen in particular how the lower housing part 10 is fastened to the upper housing part 8 by means of fastening screws 26.
• Fig. Ld shows a view according to AA in Fig. Lc), ie a view of the upper housing part 8 from below.
• Fig. Le shows a view according to BB in Fig. Lc), ie a view of the lower housing part 10 from above. It can be seen how the polarization filter 2 is rotatably attached to the lower part 10.
• the polarization filter 2 is enclosed in a mounting ring 30.
• the mounting ring 30 has an incision on its outer edge, in which a drive belt 31 runs.
• This rubber drive belt 31 is tensioned around the mounting ring 30 with the aid of a drive wheel 33.
• the drive wheel 33 is driven by a motor which is fastened on the lower housing part 10 and projects into the upper housing part 8, as a result of which the polarization filter 2 can be rotated.
• the polarization filter 2 is mounted on three freely rotatable guide rollers 34, which likewise engage from the outside in specifically provided, V-shaped flanks of the mounting ring 30. This guiding of the polarization filter 2 from the outside allows the observation to be guided centrally through the center of the filter.
• FIG. 2 shows a further exemplary embodiment of the present invention, in which the observation is not implemented electronically.
• the section shown in FIG. 2 corresponds essentially to the section according to FIG. 1 b), but here there is no display 7, but rather a disk 36 is simply arranged upwards, which prevents the interior 21 of the upper housing part 8 from becoming dirty , If necessary, it is possible to replace the pane 36 with a magnifying lens in order to make security features on the object 4 more recognizable.
• specific diaphragms 35 are provided here, which prevent light from falling directly from the light sources 1 onto the observation disk 36.
• aperture 35 may be about parallel to the axis of the light sources 1 plane plates, but it is also possible, eg. At a round disc 36 to form the aperture in the form of a conical truncated cone. Again, on the object
• a filter 5 which filters light components out of the spectral range of the light sources 1 (UV filter). It is also possible provided a UV filter is sufficiently efficient

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• Spectroscopy & Molecular Physics (AREA)
• Investigating Or Analysing Materials By Optical Means (AREA)
• Studio Devices (AREA)
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• 2003
  • 2003-03-25 AT AT03745731T patent/ATE352077T1/de active
  • 2003-03-25 EP EP03745731A patent/EP1490840B1/fr not_active Expired - Lifetime
  • 2003-03-25 AU AU2003209915A patent/AU2003209915B8/en not_active Ceased
  • 2003-03-25 US US10/509,735 patent/US20050213078A1/en not_active Abandoned
  • 2003-03-25 CA CA002481118A patent/CA2481118A1/fr not_active Abandoned
  • 2003-03-25 WO PCT/CH2003/000191 patent/WO2003085609A2/fr active IP Right Grant
  • 2003-03-25 DE DE50306308T patent/DE50306308D1/de not_active Expired - Lifetime

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