Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
• • 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
  • G01—MEASURING; TESTING
  • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
  • G01J1/00—Photometry, e.g. photographic exposure meter
  • G01J1/10—Photometry, e.g. photographic exposure meter by comparison with reference light or electric value provisionally void
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B42—BOOKBINDING; ALBUMS; FILES; SPECIAL PRINTED MATTER
  • B42D—BOOKS; BOOK COVERS; LOOSE LEAVES; PRINTED MATTER CHARACTERISED BY IDENTIFICATION OR SECURITY FEATURES; PRINTED MATTER OF SPECIAL FORMAT OR STYLE NOT OTHERWISE PROVIDED FOR; DEVICES FOR USE THEREWITH AND NOT OTHERWISE PROVIDED FOR; MOVABLE-STRIP WRITING OR READING APPARATUS
  • B42D25/00—Information-bearing cards or sheet-like structures characterised by identification or security features; Manufacture thereof
  • B42D25/20—Information-bearing cards or sheet-like structures characterised by identification or security features; Manufacture thereof characterised by a particular use or purpose
  • B42D25/29—Securities; Bank notes
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B42—BOOKBINDING; ALBUMS; FILES; SPECIAL PRINTED MATTER
  • B42D—BOOKS; BOOK COVERS; LOOSE LEAVES; PRINTED MATTER CHARACTERISED BY IDENTIFICATION OR SECURITY FEATURES; PRINTED MATTER OF SPECIAL FORMAT OR STYLE NOT OTHERWISE PROVIDED FOR; DEVICES FOR USE THEREWITH AND NOT OTHERWISE PROVIDED FOR; MOVABLE-STRIP WRITING OR READING APPARATUS
  • B42D25/00—Information-bearing cards or sheet-like structures characterised by identification or security features; Manufacture thereof
  • B42D25/30—Identification or security features, e.g. for preventing forgery
  • B42D25/328—Diffraction gratings; Holograms
• • G—PHYSICS
  • G06—COMPUTING; CALCULATING OR COUNTING
  • G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
  • G06K19/00—Record carriers for use with machines and with at least a part designed to carry digital markings
  • G06K19/06—Record carriers for use with machines and with at least a part designed to carry digital markings characterised by the kind of the digital marking, e.g. shape, nature, code
  • G06K19/08—Record carriers for use with machines and with at least a part designed to carry digital markings characterised by the kind of the digital marking, e.g. shape, nature, code using markings of different kinds or more than one marking of the same kind in the same record carrier, e.g. one marking being sensed by optical and the other by magnetic means
  • G06K19/083—Constructional details
  • G06K19/086—Constructional details with markings consisting of randomly placed or oriented elements, the randomness of the elements being useable for generating a unique identifying signature of the record carrier, e.g. randomly placed magnetic fibers or magnetic particles in the body of a credit card
• • 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
• • B42D2035/50—

Definitions

• the invention relates to an optical sensor for detecting characteristic reflection patterns caused by randomly distributed and / or oriented micro-reflectors.
• the invention further relates to the use of a sensor according to the invention for the identification and / or authentication of objects.
• Security elements are preferably inseparably connected to the objects to be protected. The attempt to separate the security elements from the object preferably leads to their destruction, so that the security elements can not be misused.
• the authenticity of an object can be verified by the presence of one or more security elements.
• Optical security elements such as e.g. Watermarks, specialty inks, guilloche patterns, micro-typefaces and holograms are established worldwide.
• An overview of optical security elements, which are particularly but not exclusively nii the Dokurnentenschutz suitable, is the following book: Rudolf L. van Renesse, Optical Document Security, Third Edition, Artech House Boston / London, 2005 (pp 63-259).
• optically variable security elements that produce a different visual impression under different viewing angles.
• Such security elements have, for example, optical diffraction structures which reconstruct different images at different viewing angles. Such effects can not be reproduced with the normal and widely used copying and printing techniques.
• Embossed holograms are characterized in that the light-diffracting structure is converted into a three-dimensional relief structure, which is transferred to a stamping mold.
• This embossing mold can be embossed as a master hologram in plastic films. This makes it possible to produce a large number of security elements cost-effectively.
• the disadvantage, however, is that security elements thus produced always have the same embossed hologram.
• the embossed holograms are indistinguishable.
• DE 102007044146Al a transparent thermoplastic material is described, in which so-called metal identification platelets are introduced with a maximum length of less than 200 microns and a thickness of 2-10 microns.
• the material may be in the form of sheets in card-shaped data carriers such as e.g. Identity cards can be used as a security element.
• the metal identification platelets may have through holes and diffractive structures.
• DE 102007044146A1 describes that the authenticity of an object can be checked by observing the metal identification platelets under a microscope.
• a disadvantage of a microscopic authenticity check is the high expense. Complete coverage of the supply chain requires fast and reliable proof of authenticity at various points.
• Barcodes are pure features for the recognition and tracking of an object, which have no security features. They are easy to copy and fake.
• a combination of product tracking features and anti-counterfeiting features provide RFID chips, but their use is limited because of their relatively high cost, slow read speed, and sensitivity to electromagnetic interference. It would therefore be desirable to be able to read a security element by machine in order to enable automated product tracking along the supply chain on the one hand, and to be able to perform a mechanical authentication check on the other hand.
• the object is to provide a device that allows identification and / or authentication of an object based on individual characteristics.
• the device should be able to be used for product tracking.
• the device should be simple and inexpensive to manufacture, intuitive and easy to use, flexible in use and extensible, deliver reproducible and transferable results, and be ready for mass production.
• the materials described in DE102007044146A1 can be uniquely identified and authenticated on the basis of the random distribution and / or orientation of the metal identification platelets.
• the metal identification plates are irradiated with electromagnetic radiation.
• the radiation reflected at different angles on the randomly distributed and / or oriented metal identification platelets is detected by means of suitable detectors.
• the reflection pattern thus obtained is characteristic of the random distribution and / or orientation of the metal identification platelets and allows the unique identification and / or authentication of an article to which the metal identification platelets are connected.
• metal identification tags are generally referred to as microreflectors.
• the present invention relates to a sensor for detecting a characteristic reflection pattern caused by irradiation of an article comprising randomly distributed and / or oriented micro-reflectors.
• the sensor according to the invention comprises at least the following components:
• a source of electromagnetic radiation arranged so that electromagnetic radiation can be transmitted to the object at an angle ⁇
• a photodetector for receiving reflected radiation arranged to detect the radiation reflected from the object at an angle ⁇
• the sensor according to the invention is designed so that electromagnetic radiation can be sent at an angle ⁇ to a surface of an object.
• the angle ⁇ refers to the normal to the surface, ie perpendicular to the surface of the object standing straight line - also referred to below as surface normal.
• the angle ⁇ is in the range of 0 to 60 °, preferably in the range of 15 ° to 40 °, more preferably in the range of 20 ° to 35 ° and most preferably in the range of 25 ° to 30 °.
• all sources of electromagnetic radiation which emit radiation which is at least partially reflected by the microreflectors used can be used in the sensor according to the invention as source of electromagnetic radiation or radiation source.
• partial reflectivity is meant a reflectivity of at least 50%, i. At least 50% of the irradiated radiation intensity is reflected by the micro-reflectors.
• the electromagnetic radiation used must be able to penetrate the material at least partially, i.
• the material must be at least partially transparent to the electromagnetic radiation used.
• partial transparency is meant a transmissivity of at least 50%, i. At least 50% of the irradiated radiation intensity penetrates the material.
• the radiation source preferably emits electromagnetic radiation in the range from 300 nm to 1000 nm, preferably in the range from 350 nm to 800 nm.
• the sensor according to the invention comprises 1 to 6 radiation sources, preferably 1 to 4 radiation sources, particularly preferably 1 or 2 radiation sources.
• laser diodes are preferred as the radiation source.
• Laser diodes are well known; They are semiconductor devices in which a p-n junction is operated with heavy doping at high current densities. The choice of semiconductor material determines the emitted wavelength. Preferably, laser diodes are used which emit visible radiation.
• Class 1 or 2 lasers refer to the laser protection classes according to the standard DIN EN 60825-1: Lasers are classified in classes according to the danger to eyes and skin. Class 1 includes lasers whose irradiation values are below the maximum permissible irradiation values, even during continuous irradiation. Class 1 laser scanners are not hazardous and do not require any further protective measures other than the corresponding marking on the device. Class 2 includes lasers in the visible range, where exposure below 0.25 ms is harmless to the eye (the duration of 0.25 ms corresponds to a blinking reflex affecting the eye can automatically protect against prolonged irradiation). In a particularly preferred embodiment, class 2 laser diodes having a wavelength between 600 nm and 780 nm are used.
• the sensor according to the invention is designed so that the electromagnetic radiation reflected by the object at one or more angles can be detected by means of one or more photodetectors.
• the sensor according to the invention is moved at a constant distance relative to an object comprising microreflectors.
• the object is irradiated by means of electromagnetic radiation. Since the surface of the object directly reflects part of the radiation, no photodetectors are present in the region of the radiation reflected by the surface according to the invention. The radiation reflected directly from the surface of the object is so strong that additional reflections from microreflectors are difficult or even impossible to recognize. Rather, to increase the signal-to-noise ratio, the photodetectors are in an area where they detect the reflected radiation from such microreflectors whose reflective surfaces are not parallel to the surface of the object.
• microreflectors whose reflective surfaces are not parallel to the surface of the article, also has the advantage that counterfeiting with e.g. vapor-deposited metal spots, which are always parallel to the surface of the object, can be reliably detected.
• the location of the reflective surface with respect to a surface of the article is also referred to herein as orientation.
• At least one photodetector is arranged at an angle ⁇ to the surface normal, wherein the amounts of the angles ⁇ and ⁇ are different (
• photodetectors in the sensor according to the invention are arranged at an angle ⁇ around the directly reflected beam.
• the size of the angle ⁇ is dependent on the choice of the size of the angle ⁇ .
• the size of the angle ⁇ is in the range of 5 ° to 60 °, preferably in the range of 5 ° to 30 °, particularly preferably in the range of 10 ° to 20 °, where always should apply:
• the magnitude of the angle ⁇ is in the range of
• the number of photodetectors m in the sensor according to the invention is 1 to 6 per radiation source, preferably 1 to 4 per radiation source, more preferably 1 to 2 per radiation source.
• 2 photodetectors are used per radiation source, which are arranged at an angle Y 1 and ⁇ 2 around the beam reflected directly from the surface.
• ⁇ i - ⁇ 2 .
• the photodetectors and the associated radiation source preferably lie in one plane.
• Photodiodes are semiconductor diodes that convert electromagnetic radiation at a p-n junction or pm transition through the internal photoelectric effect into an electrical current.
• a phototransistor is a bipolar transistor with a pnp or npn layer sequence whose pn junction is accessible to the base-collector barrier layer for electromagnetic radiation. It resembles a photodiode with connected amplifier transistor.
• the sensor according to the invention has optical elements which generate an annular beam profile.
• optical elements refers to those components which are arranged in the beam path between a source of electromagnetic radiation and at least one photodetector and are used to change the beam profile (focusing, beam shaping). In particular, these are lenses, apertures, diffractive optical elements and the like.
• a beam profile is understood to mean the two-dimensional intensity distribution in the cross section.
• the cross section lying in the plane in which microreflectors are located.
• the cross section is in the focal point of the sensor.
• the intensity is highest in the cross-sectional center of the beam and decreases toward the outside.
• the gradient of the intensity in a beam-shaped beam profile is in a first direction lowest, while highest in a second direction perpendicular to the first direction.
• the intensity distribution of the linear beam profile is preferably symmetrical, so that the cross-sectional profile in the focal point can be characterized by two mutually perpendicular axes, one of which runs parallel to the highest intensity gradient and the other parallel to the lowest intensity gradient.
• the width of a cross-sectional profile-or also beam width- is understood to be the distance from the center of the cross-sectional profile in the direction of the lowest intensity gradient at which the intensity has dropped to half of its value in the center.
• the thickness of a cross-sectional profile-or jet thickness- is understood to be the distance from the center of the cross-sectional profile in the direction of the highest intensity gradient at which the intensity has fallen to half of its value in the center.
• the beam width and the beam thickness are preferably adjusted to the size and concentration of the microreflectors in the material whose reflection pattern is to be detected.
• the beam thickness is preferably in the order of magnitude of the average size of the microreflectors.
• the beam width is preferably of the order of the mean distance between two microreflectors.
• An average size is understood as the arithmetic mean. In terms of magnitude, it is understood that two quantities differ or are equal to one another by a factor smaller than 10 and larger than 0.1.
• the beam width is in the range of 2.5 mm to 7 mm, preferably in the range of 3 mm to 6.5 mm, more preferably in the range 4 mm to 6 mm and most preferably in the range 4, 5 mm to 5.5 mm.
• the beam thickness is in the range of 5 ⁇ m to 1000 ⁇ m. To achieve a high signal-to-noise ratio and to dissolve fine structures, a small beam thickness of 5 ⁇ m to 50 ⁇ m is advantageous.
• the signal-to-noise ratio increases, as the intensity is distributed over a smaller area. With decreasing size of the cross-sectional profile even finer structures can be resolved. Empirically, it has been found that as the size of the cross-sectional profile decreases, however, it becomes increasingly difficult to achieve reproducible signals. Apparently, this is because the material with the micro-reflectors can no longer be positioned sufficiently accurately with respect to the decreasing cross-sectional profile.
• the preferred beam thickness is in a focused on the object beam in the range of 5 microns to 50 microns, preferably in the range of 10 microns to 40 microns, more preferably in the range of 20 microns to 30 microns.
• the focal point is located at a distance of 0.5 to 10 mm from the sensor.
• a very compact design of the sensor according to the invention can be realized by omitting a focusing of the beam by means of lenses. Instead, using a
• the beam thickness is in the range of 200 .mu.m to 1000 .mu.m, preferably in the range of
• the beam width in the range of 2 mm to 5 mm, preferably in the range of 2.5 mm to 3.5 mm.
• the sensor according to the invention preferably has means for connecting a plurality of sensors or for connecting a sensor to a holder.
• the sensor preferably has positive connection means on one side and negative connection means on an opposite side, so that a sensor can be connected in a defined manner on both sides with a further sensor in each case, with the further sensors in turn on the still free sides other sensors can be connected.
• This modular principle allows the connection of a plurality of sensors in a predetermined manner. For example, protrusions which can be plugged into recesses as negative connection means come into consideration as positive connection means. Other known to the expert connecting means such as insertion rails or the like are conceivable.
• Several sensors are preferably interconnected so that the beam widths of all sensors are arranged along a line.
• connection of two or more sensors is reversible, i. it is solvable.
• the connecting means can also be used to attach the sensor according to the invention to a holder.
• ⁇ By connecting multiple sensors, it is possible to record more reflection data for a constant acquisition duration, thereby increasing the security of identification and / or authentication.
• connected sensors will have multiple areas in it
• Time interval irradiated and reflected radiation detected Accordingly, larger amounts of data are recorded which characterize the object. This increases the accuracy with which an item from a large number of similar items can be securely identified and authenticated.
• the inventive, releasable combination of multiple sensors offers the user the
• a device comprising two or more sensors, which are reversibly connected to each other directly or via a spacer, is also an object of the present invention.
• the sensor has a housing into which the optical components are introduced.
• the housing of the sensor other components can be introduced, for example, the control electronics for a laser, signal preprocessing electronics, complete evaluation and the like.
• the housing preferably also serves to anchor a connection cable with which the sensor according to the invention can be connected to a control unit and / or a data acquisition unit for controlling the sensor and / or for detecting and further processing the characteristic reflection patterns.
• the sensor preferably also has a window which, together with the housing, protects the optical components from damage and contamination.
• the window is at least partially transparent to the wavelength of the radiation source used.
• the sensor according to the invention is suitable in combination with a control and data acquisition unit for identifying and / or authenticating objects.
• the present invention thus also relates to the use of the sensor according to the invention in a method for identifying and / or authenticating an object.
• Identification is understood as a process that serves to uniquely recognize a person or an object.
• Authentication is the process of verifying (verifying) an alleged identity.
• the authentication of objects, documents, persons or data is a statement that they are authentic - that is, they are unchanged, not copied and / or not faked originals.
• the article to be identified and / or authenticated includes microreflectors attached to and / or incorporated within the article and randomly distributed and / or oriented.
• the micro-reflectors can be connected to the object itself.
• a security element e.g., a tag
• Examples of such security elements are described in DE 102007044146A1 or in the not yet disclosed application PCT / EP2009 / 000450.
• a microreflector is characterized in that it comprises at least one surface which reflects incident electromagnetic radiation in a characteristic manner.
• the characteristic reflection is characterized in that electromagnetic radiation having at least one wavelength is reflected in at least one direction predetermined by the angle of incidence, wherein the proportion of the reflected radiation with the at least one Wavelength is greater than the sum of the portions of the absorbed and transmitted radiation of at least one wavelength.
• the degree of reflection of the at least one surface is therefore greater than 50%, wherein the degree of reflectance, the ratio of the intensity of the electromagnetic radiation having at least one wavelength which is reflected from the surface, based on the intensity of the electromagnetic radiation having the at least one wavelength on the surface hits, it is understood.
• a reflective surface is referred to as a reflective surface.
• the reflective surface of a micro-reflector has a size between l * 10 "14 m 2 and 1 * 10 5 m 2.
• the size of the reflecting surface in the range of l * 10" 12 m 2 and 1 * 10 -6 m 2 , more preferably between 1 * 10 "10 m 2 and 1 * 10 " 7 m 2 .
• the microreflectors have a maximum length of less than 200 microns and a thickness of 2-10 microns, with a round, elliptical, or n-square shape with n ⁇ S.
• Elliptic is here and below not to be understood in the strict mathematical sense.
• a rectangle or parallelogram or trapezoid or generally n-corner with rounded corners is here and below also understood to be elliptical.
• the microreflectors contain at least one metallic component. It is preferably a metal from the series aluminum, copper, nickel, silver, gold, chromium, zinc, tin or an alloy of at least two of said metals.
• the microreflectors may be coated with a metal or alloy, or may be made entirely of a metal / alloy.
• metal identification platelets as described by way of example in WO 2005/078530 A1, are used as microreflectors. They have reflective surfaces. If a large number of such metal identification platelets are randomly distributed and / or oriented in a transparent layer, a characteristic reflection pattern results upon irradiation of the transparent layer, which can be used for identification and authentication.
• Random distribution and / or orientation means that the position of individual microreflectors and / or the orientation of individual microreflectors within the transparent layer can not be foreseen by the production process.
• the methods described in DE 102007044146Al for producing a thermoplastic material containing microreflectors are suitable for random distribution and / or Orientation of microreflectors in a transparent layer to produce.
• the location and / or orientation of individual microreflectors is subject to random fluctuations in the manufacturing process. The location and / or orientation of individual microreflectors therefore can not be easily reproduced.
• microreflectors have a preferred position and / or orientation. To this preference and / or preferential orientation is a distribution, which can be determined by the manufacturing process. However, the position and / or orientation of individual microreflectors remains uncertain.
• the microreflectors have the property that they reflect electromagnetic radiation of at least one wavelength when an arrangement of an electromagnetic radiation source, at least one reflective surface of at least one microreflector and a detector for the reflected electromagnetic radiation obeys the law of reflection.
• the method of authenticating an item includes at least the following steps:
• step (G) issuing a notification of the authenticity of the item depending on the result of the comparison in step (F).
• the object to be authenticated and / or the sensor are moved relative to each other to record the micro-reflectors flashing at different locations and / or at different orientation angles as a function of the relative position of the article to radiation source (lasers) and photodetectors.
• the attitude change may be continuous at constant speed, accelerating or decelerating, or discontinuous, i. e.g. gradually.
• step (E) The repetition of steps (B), (C) and (D) in step (E) is carried out until a sufficient number of micro-reflectors has been detected.
• This sufficient number is given by the particular application.
• the reflection patterns of the individual objects must be sufficiently different.
• the likelihood that the reflection patterns from two different objects will be the same decreases.
• the number of objects to be distinguished and the certainty with which an object is to be authenticated determines the number of microreflectors to be detected.
• step (F) a so-called 1: 1 comparison between the currently detected reference pattern and the reflection pattern of the presumed object (target pattern) takes place.
• the reflection pattern represents the reflections of microreflectors detected as a function of the position of the object with respect to the sensor.
• the reflection pattern is therefore e.g. in the form of a number table in which the intensities of the radiation reflected by micro-reflectors measured at different angles at different locations are detected.
• Such a number table can be directly compared with a target number table. It is also possible to use the measured intensity distribution to create a different representation of a reflection pattern by means of mathematical operations before a comparison with a desired pattern is carried out.
• the senor can be used to directly identify an object based on its characteristic reflection pattern.
• a method of identification of an object with the aid of the sensor according to the invention comprises at least the steps (A) to (G) already discussed in the method for authentication in the embodiments discussed there, wherein in step (G) instead of a message about the authenticity, a notification is made about the identity of the object :
• step (G) issuing a notification of the identity of the subject depending on the result of the comparison in step (F).
• step (F) of the method according to the invention the reflection pattern of the object under consideration is compared with reflection patterns which have already been determined at an earlier time.
• identity of an object is determined by the reflection pattern and there is a comparison of the considered reflection pattern with all stored in a database reflection patterns already detected objects (1: n adjustment).
• the use of the sensor according to the invention offers the advantage that an identification and / or authentication of an object can be carried out by machine or mechanically assisted and a quantitative evaluation allows the probability with which an object corresponds to an alleged object. Machining or support allows the inspection of a larger number of objects based on their characteristic reflection patterns in a shorter time and at a lower cost than a (purely) personal execution e.g. with the aid of a microscope as described in DE 102007044146Al. In addition, machine execution or machine support allows comparison of reflection patterns that have been authenticated at different times. This allows tracking of items (track and trace).
• FIG. 2 block of the sensor according to the invention in cross section
• FIG. 4 Schematic representation of a linear beam profile
• FIG. 5 is a schematic representation of a preferred embodiment of the sensor according to the invention
• Fig. 6 plano-convex cylindrical lens for generating a linear beam profile
• FIGS. 1a and 1b show a sensor 1 according to the invention without optical components in a perspective view.
• FIG. 2 shows the sensor 1 from FIGS. 1a and 1b in cross-section.
• the central element of the sensor 1 forms a block 10, which is preferably designed in one or two pieces, and which serves to accommodate all optical components of the sensor according to the invention.
• Optical components are understood to be all components of the sensor which are arranged in the beam path between the radiation source and the photodetector, including the laser and the photodiodes themselves.
• Optical elements form a selection of the optical components; they serve for beam shaping and focusing.
• lenses, diaphragms, diffractive optical elements and the like are referred to as optical elements.
• the optical block 10 includes a designated outer surface 18 which is directed toward the same upon detection of characteristic reflection patterns of an object.
• the block 1 comprises passages 11, 12, 13 which converge toward the designated outer surface 18 - hereinafter simply referred to as outer surface.
• a first passage 11 serves to receive the Sirahlenscher. This passage 11 extends at an angle ⁇ A to the normal of the outer surface.
• the normal of the outer surface or outer surface normal is the straight line perpendicular to the outer surface, which is directed in the direction of the bushings.
• the senor When using the inventive sensor for identifying and / or authenticating an object, the sensor is preferably aligned with respect to the surface of the article so that the surface of the article and the outer surface are parallel to each other.
• electromagnetic radiation is incident on the surface of the object at an angle ⁇ with respect to the surface normal.
• the angle ⁇ A in this case corresponds to the angle of incidence ⁇ of the incident radiation.
• the block of the sensor according to the invention comprises at least one further corresponding bushing 12, 13 for receiving the photodetector.
• the block of the sensor according to the invention may comprise further feedthroughs for receiving photodetectors.
• the block of the sensor according to the invention may comprise further feedthroughs for receiving photodetectors.
• Block exactly two feedthroughs 12, 13 for receiving photodetectors lie together with the implementation 11 for the radiation source in a plane. They are preferably at an angle Y 1 and ⁇ 2 to the outer surface normal.
• the photodetectors are in the
• angles ⁇ i and ⁇ 2 are in the range of 5 ° to 60 °, preferably in the range of 5 ° to 30 °, particularly preferably in the
• All feedthrough 11, 12, 13 are preferably in one plane.
• FIGS. 1 a, 1 b and 2 comprising a block with lead-throughs for receiving a radiation source and two photodetectors offers the advantage that the optical components can be arranged in a defined manner to one another in a simple manner.
• there is a stop in the passage for the radiation source against this stop, the radiation source is pushed into the bushing, so that it occupies a predetermined fixed position with respect to the block and the other two bushings.
• the radiation source already has optical elements for beam shaping and focusing connected to it, which is generally customary, for example, in the case of the commercially available laser radiation sources, then the focal point of the radiation source is clearly fixed by the fixation of the radiation source.
• the further feedthroughs for receiving the photodetectors can also be provided with a stop, wherein the position of the photodetectors must be less accurate than the position of the radiation source.
• the block 10 can be made in one simple way, for example by means of injection molding of plastic one or two pieces.
• components can be produced with high accuracy in large quantities and in a short time. This allows cost-effective mass production of sufficiently precise components.
• the bushings may already be provided in the injection molding tool or be subsequently introduced into the block by means of, for example, bores. All components of the block are already preferred by injection molding - -
• the sensor 1 according to the invention is further characterized in that the center axes of the bushings 11, 12, 13 intersect at a point 20 which lies outside the block 10 (see FIG. 2). Surprisingly, it has been found that it is advantageous for the detection of reflection patterns if the point of intersection 20 of the center axes lies at a distance of 0.5 to 10 mm from the outer surface. In a preferred embodiment, the intersection point 20 is simultaneously the focal point of the radiation source.
• the senor according to the invention is accordingly guided at a distance over this object, so that the point of intersection of the central axes lies on the surface of the object.
• the positioning of the surface to be detected of an object with respect to the radiation source and the photodetectors is simple and sufficiently accurate.
• the angle of the sensor with respect to the surface of the object must be more and more accurately maintained in order to be able to detect a predetermined area of the surface so that the positioning requirements increase.
• the radiation intensity decreases with increasing distance from the radiation source, so that with an increasing distance between sensor and object the correspondingly reduced radiation intensity arriving at the object would have to be compensated by a higher power of the radiation source.
• the sensor according to the invention is preferably equipped with a class 1 or 2 laser in order to operate the sensor without extensive protective measures. This is especially true since the sensor is "open" (ie, the laser beam exits the sensor unhindered), which means that the power of the radiation source can not be arbitrarily increased, thus, a short distance of 0.5 to 10 mm according to the invention advantageous.
• the block 10 in FIGS. 1a, 1b and 2 further comprises holding means 30 for receiving and fixing a window.
• the window (not shown in the figure) is at least partially transparent to the wavelength of the radiation source used. Under partial permeability becomes understood a transmissivity of at least 50%, ie 50% of the irradiated radiation intensity penetrates the window.
• the partial sections 3 (a) and 3 (b) show a housing 50 in a perspective view into which the sensor from FIGS. 1 a, 1 b and 2 can be introduced.
• Part 3 (c) shows a to
• Housing associated cover 60 The housing has passages 51, 52.
• Feedthroughs may be used as connection means to releasably connect multiple sensors together or to secure the sensor to a support.
• the senor 60 has corresponding recesses 62. Via a cable feedthrough 55, the sensor is connected to a control electronics and / or a computer unit for receiving the reflection data.
• FIG. 5 shows in a schematic representation a further preferred embodiment of the sensor 1 according to the invention.
• FIG. 5 (a) shows the sensor from the side in cross section, FIG. 5 (b) from the underside facing the surface 200.
• the sensor 1 comprises a radiation source 70 and a photodetector 80. If the outer surface 18 of the sensor i is guided in parallel over the surface 200 of an object, then radiation 100 falls on the surface 200 at an angle .alpha. To the normal 14. The surface 200 reflects Radiation 110 is returned to the normal 14 at an angle ⁇ . It applies according to the law of reflection
• the line-shaped beam profile is generated in the present example by means of a shutter 90.
• the distance between sensor (outer surface 18) and object (surface 200) is preferably between 0.2 and 10 mm.
• the sub-figures 4 (a) and 4 (b) illustrate a line-shaped beam profile with a beam width SB and a beam thickness SD.
• Partial figure 4 (a) shows the two-dimensional cross-sectional profile of a beam in the focal point. At the center of the cross-sectional profile is the highest intensity. The intensity / decreases to the outside, wherein there is a first direction (x), in which the intensity decreases the most / with increasing distance A to the center, and a further direction (y), which is perpendicular to the first direction (x) in which the intensity decreases the weakest with increasing distance A to the center.
• Sub-figure 4 (b) shows the intensity profile / as a function of the distance A from the center.
• the beam width and the beam thickness are defined as the distances from the center in which the intensity / to 50% of its maximum value in the Center has dropped, here the beam width in the y-direction and the beam thickness in the x-direction.
• FIG. 6 shows by way of example how a line-shaped beam profile is generated by means of a plano-convex beam
• Cylinder lens 300 can be generated.
• the cylindrical lens 300 acts in a plane as

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• 2008
  • 2008-10-11 DE DE102008051409A patent/DE102008051409A1/de not_active Withdrawn
• 2009
  • 2009-04-17 WO PCT/EP2009/002809 patent/WO2010040422A1/de active Application Filing
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