TW201130684A - Motor-vehicle-registration plate encompassing at least one translucent, retroreflective layer - Google Patents

Abstract

The present invention relates to a motor-vehicle-registration plate (1) encompassing at least one translucent, retroreflective layer (2), where the plate (1) has at least one transparent laser-inscribable intermediate layer (3) and one transparent protective layer (4), and the intermediate layer (3) has been arranged between the protective layer (4) and the translucent, retroreflective layer (2).

Description

201130684 VI. Description of the Invention: [Technical Field] The present invention relates to a motor vehicle license plate comprising at least half of a transparent retroreflective layer. This licence is particularly applicable to the registration mark of motor vehicles. [Prior Art] A motor vehicle license plate is usually illuminated by two or three lights attached above or below the license plate. However, the disadvantage is that the license plate is not illuminated uniformly. In addition, lighting fixtures attached above or below the exterior of the license plate limit the likelihood of optimization of the vehicle design. There are also known illumination devices that illuminate the license plate via a light source attached to the back. For example, a light-emitting foil and an optical conductor can be used as the light source. A specific example of this type of illuminating license plate is described in the publications of WO 2007/0 1 2306 'EP-A-1 262 373 and EP-A-1 477 368. According to WO 2007/01 2306, the optical conductor can illuminate the license plate from the front of the retroreflective sheeting. However, the disadvantage here is that some minor damage to the optical conductor causes undesired light interference. This significantly reduces the visibility of the license. Such a appearance is a scratch type of damage which can be, for example, caused by a collision of stones or during cleaning of the vehicle' and thus cannot be avoided for a long time. EP-A-1 262 373 describes a license plate which is illuminated via a light-emitting foil attached to the back. The front side of the licence is protected by a transparent cover so that minor damage does not destroy the identification of the license. The position of the symbol drawn on the license plate is on the symbol substrate, and the symbol may, for example, be provided on the inner or outer surface of the transparent cover. If the symbol is applied to the outer surface of the transparent cover by -5-201130684, the symbol may be detached via environmental influences (e.g., via cleaning of the vehicle), and the longer the result, the worse the recognition. If the symbol is applied to the inner surface, the manufacture of the license plate is relatively complicated. In this case, it is not possible to supply a pre-manufactured unmarked license plate (unsigned) to an individual license position (where the registration mark is provided to the license plate), whereas the license plate must be assembled after the symbol has been applied. A setting similar to that described in the publication EP-A-1 262 373 is described in EP-A-1 477 368. This setting also has the above problem. SUMMARY OF THE INVENTION In view of this prior art, it is an object of the present invention to provide a motor vehicle license plate having a superior property variation curve. In particular, it should be possible to illuminate the license plate from the back to provide a variety of possibilities for motor vehicle design to the designer. At the same time, it should be possible to transport the pre-manufactured type of license plate to the individual lighting position if the license plate only has to be provided with the corresponding symbol at the location of the license so that the completed license plate can be supplied to the end user. There should be no need for any complicated assembly to set up the license. Another object of the present invention is to provide a motor vehicle license plate that can be manufactured quickly and in a particularly simple manner. Another object of the present invention is to provide a license plate that is particularly resistant to counterfeiting. Another object of the present invention is to provide a license plate having superior mechanical properties. In particular, such licences should have high scratch and impact resistance and a pair of rings

S -6- 201130684 Resistance to environmental impact. A motor vehicle license having all the features of claim 1 achieves these objectives and also achieves other purposes that are not explicitly mentioned but are easily derived or inferred from the conditions discussed in the introduction to this document. An advantageous specific example of a license for a motor vehicle registration mark in accordance with the present invention is protected by the scope of the patent application of the scope of claim 1 of the patent application. The invention therefore provides a license plate comprising at least half of a transparent retroreflective layer, characterized in that the license plate has at least one transparent laser printable intermediate layer and a transparent protective layer, wherein the intermediate layer has been disposed on the protective layer and the half Between transparent retroreflective layers. This provides an unforeseen route to provide a motor vehicle license plate having the superior properties described above. Surprisingly, in accordance with the teachings of the present invention, a license plate that can be illuminated from the back can be provided, thereby eliminating the damage to the design of the license plate caused by the need to provide illumination means above or below the license plate. At the same time, it is possible to transport a pre-manufactured type of licence to an individual license location in the event that the licence must only be provided with a corresponding symbol at the location of the license so that the completed licence can be supplied to the end user. There should be no need for any complicated assembly for the license plate. Further, the motor vehicle license plate according to the invention can be manufactured quickly and in a particularly simple manner. Furthermore, the license plate of the present invention is particularly resistant to counterfeiting. The method of the present invention is particularly capable of providing a license plate having superior mechanical properties. In particular, such licences should have high scratch and impact resistance and resistance to environmental 201130684 impact. [Embodiment] A motor vehicle license plate according to the present invention comprises at least half of a transparent retroreflective layer. This type of layer is permeable to incident light on the back side, but the incident light reflected on its front side is intended to exhibit such properties, and these layers may, for example, contain scatterers (eg, silver plated) The glass hemisphere, or may contain structural effects. The nature of the materials used to make the layers is not critical, but is preferably a transparent plastic. Preferred plastics are, in particular, polycarbonates, polymethyl methacrylates, polybutyrates, polystyrenes, and in particular, syndiotactic polystyrene-butadiene copolymers. Retroreflective foils and layers which may contain structural effects (e.g., diamond or cubic corner patterns) have been specifically described in U.S. Patent Nos. 4,58,258, 5,1,22,902, WO 98/203, and DE 699 04 5 1 2, respectively. Foil with scatterers is described in U.S. Patent 4,005,538. The layers may in particular be purchased from 31^ using the trademark 3 (: 〇 ^ 111 "one foil type. The license plate has at least one laser printable intermediate layer as an integral element of the invention. The laser printable intermediate layer may It is made from any material which can change its transmittance and/or color properties via laser irradiation. Preferably, the material comprises at least one plastic comprising nano particles. The plastic preferably has high transparency, and the transparency can be The laser light is lowered by irradiation. Preferred plastics are, in particular, polycarbonates, polymethyl methacrylates and polyamines, and particularly preferably polyamines are present in the intermediate layer.

S -8 - 201130684 Polymethyl methacrylates are generally obtained by free radical polymerization of a mixture comprising methyl methacrylate. The mixture typically comprises at least 40% by weight (preferably at least 60% by weight and particularly preferably at least 80% by weight) of methyl methacrylate based on the weight of the monomers. The mixture may also contain other (meth) acrylates which are copolymerizable with methyl methacrylate. The term (meth) acrylates encompasses methacrylates and acrylates and mixtures of the two. These monomers are conventional. In particular, it is a (meth) acrylate derived from a saturated alcohol such as methyl acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, (methyl) ) tert-butyl acrylate, amyl (meth) acrylate, 2-ethylhexyl (meth) acrylate; (meth) acrylates derived from unsaturated alcohols such as (meth) acrylate , 2-propynyl (meth)acrylate, allyl (meth)acrylate, vinyl (meth)acrylate; aryl (meth)acrylates, such as benzyl (meth)acrylate or (a) Phenyl acrylate' wherein each aryl moiety may be unsubstituted or may have up to 4 substituents: cycloalkyl (meth)acrylates, such as (meth)acrylic acid 3-ethylidene ring Vinegar, (meth)propionic acid borneol vinegar; hydroxyalkyl (meth) acrylate, such as 3-hydroxypropyl acrylate (meth) acrylate, 3,4-dihydroxybutyl (meth) acrylate, (A) 2-hydroxyethyl acrylate, 2-hydroxypropyl (meth) acrylate; di(meth) propylene Diesters such as 1,4 -butane di(meth)acrylate; (meth)acrylates of ether alcohols such as tetrahydrofurfuryl (meth)acrylate, vinyl (meth) acrylate Oxyethoxyethyl ester; decylamine and nitrile of (meth)acrylic acid, -9- 201130684 For example, Ν·(3·dimethylaminopropyl)(meth)acrylamide, Ν-( Diethylphosphino)(meth)acrylamide, 1-methylpropenylnonylamino-2-methyl-2-propanol; sulfur-containing (meth)acrylates, such as (methyl ) ethylsulphynylethyl (meth) acrylate, 4-thiocyanobutyrate (meth)acrylate, ethylsulfonate (meth)acrylate, sulfuric acid (meth)acrylate Methyl cyanomethyl methacrylate, methyl methynyl methyl (meth) acrylate, bis ((meth) propylene decyl oxyethyl) thioether; polyfunctional (meth) acrylates such as tris(methyl) ) Trimethylmercaptopropyl acrylate. The composition to be polymerized may contain, in addition to the above (meth) acrylate, other unsaturated monomers copolymerizable with methyl methacrylate and the above (meth) acrylate. These are especially 1-olefins such as 1-hexene, 1-heptene; branched alkyls such as vinylcyclohexane, 3,3-dimethyl-1-propene, 3-methyl-1 - diisobutylene, 4-methyl-1-pentene; acrylonitrile; vinyl esters such as vinyl acetate; styrene, substituted styrenes having an alkyl substituent in the side chain (eg α-A) Styrene and α-ethylstyrene), substituted styrenes having an alkyl substituent on the ring (for example, vinyl toluene and p-methylstyrene), halogenated styrenes (for example, monochlorobenzene) Ethylene, dichlorostyrene, tribromostyrene and tetrabromostyrene): heterocyclic vinyl compounds such as 2-vinylpyridine, 3-vinylpyridine, 2-methyl-5-vinyl Pyridine, 3-ethyl-4-vinylpyridine, 2,3-dimethyl-5-vinylpyridine, vinylpyrimidine, vinylpiperidine, 9-vinylcarbazole, 3-vinylcarbazole, 4-vinylcarbazole, 1-vinylimidazole, 2-methyl-oxime-ethene

S -10- 201130684 Pyrimidazole, anthracene vinylpyrrolidone, 2-vinylpyrrolidone, N-vinylpyrrolidine, 3-vinylpyrrolidine, N-vinylcaprolactam, N-vinylbutyrate Amine, vinyl oxolane, vinyl furan, vinyl thiophene, vinylthiolane, vinyl thiazole and hydrogenated vinyl thiazole, vinyl oxazole and hydrogenated ethylene Oxazoles; vinyl and isoprenyl ethers; maleic acid derivatives such as maleic anhydride, methyl maleic anhydride, maleimide, methyl cis Butylenediimide; and dienes such as divinylbenzene. These monomers are generally used in an amount of from 〇 to 60% by weight, preferably from 0 to 40% by weight, and particularly preferably from 0 to 20% by weight, based on the weight of the monomers, and the compounds herein may be used alone. Or use in a mixture type. The polymerization is usually initiated by a known free radical initiator. Preferred initiators are, in particular, azo initiators well known to those skilled in the art, such as AIBN and 1,1-azobiscyclohexanecarbonitrile, and peroxy compounds such as methyl ethyl ketone peroxidation. , acetal acetone peroxide, dilauryl peroxide, tert-butyl 2-ethylperoxyhexanoate, ketone peroxide, methyl isobutyl ketone peroxide, cyclohexanone peroxidation , benzoyl peroxide, tert-butyl peroxybenzoate, tert-butylperoxy isopropyl carbonate, 2,5-bis(2-ethylhexylperoxy) -2,5-dimethylhexane, tert-butyl 2-ethylperoxycaproate, tert-butyl 3,5,5-trimethylperoxyhexanoate, dicumyl peroxide 1,1_bis(t-butylperoxy)cyclohexane, 1,1-bis(t-butylperoxy)-3,5,5-trimethylcyclohexane, cumylhydrogen a peroxide, a tert-butyl hydroperoxide, a bis(4-t-butylcyclohexyl)peroxydicarbonate, a mixture of two or more of the above compounds, and 5 -11 - 201130684 a compound that is not mentioned but is equally capable of forming free radicals mixture. These compounds are generally used in an amount of from 0.1 to 10% by weight, based on the weight of the monomers, preferably from 0.5 to 3% by weight. It is possible to use a plurality of poly(meth)acrylates, wherein these differences are exemplified by molecular weight or monomer composition. The layers comprising polymethyl methacrylate (especially the laser printable intermediate layer and the protective layer described below) may also contain other polymers to improve the properties. These are in particular polyacrylonitriles, polystyrenes, polyethers, polyesters, polycarbonates and polyvinyl chlorides. These polymers may be used singly or in a mixture type, and it is also possible to add various copolymers which can be derived from the above polymers to the molding composition. The weight average molecular weight Mw of the preferred homopolymers and/or copolymers which may be present in the intermediate layer can vary widely, and the molecular weight is often adjusted to suit the desired application and to the processing of the molded composition. However, it is usually in the range of 20,000 to 1,000,000 g/mole, preferably in the range of 50,000 to 500,000 g/mole, and particularly preferably in the range of 80,000 to 300,000 g/mole, but is not intended to be limiting. Polyamines which are particularly preferably present in the intermediate layer are usually produced from the following units: branched and unbranched aliphatic (6 to 14 carbon atoms) diamines, alkyl substituted or unsubstituted Cycloaliphatic (14 to 22 carbon atoms) diamines, araliphatic (14 to 22 carbon atoms) diamines, and aliphatic and cycloaliphatic dicarboxylic acids having 6 to 44 carbon atoms The latter can be replaced to some extent by aromatic dicarboxylic acids. Transparent polyamines can also be specially

S -12- 201130684 A monomer unit composition having 6 carbon atoms, 11 carbon atoms or 12 carbon atoms, wherein these are derived from intrinsic amines or derived from ω-amino carboxylic acids. Polyamines are preferably, but not exclusively, manufactured from the following units: laurylamine or ω-aminododecanoic acid, azelaic acid, sebacic acid, dodecanedioic acid, fatty acids (C18 to C36) For example, those having the trademark prip〇i®, cyclohexanedicarboxylic acids, these aliphatic acids are partially substituted by isophthalic acid, terephthalic acid, naphthalene dicarboxylic acid, and tributylisophthalic acid. Other compounds used are decanediamine, dodecanediamine, decanediamine, branched, unbranched or substituted hexamethylene diamines, and as alkyl substituted/unsubstituted cycloaliphatic Representative of a family of diamines, bis(4-aminocyclohexyl)methane, bis(3·methyl-4-aminocyclohexyl)methane, bis(4-aminocyclohexyl)propane, bis(amino ring) Hexane), bis(aminomethyl)cyclohexane, isophoronediamine or substituted pentanediamine. Examples of corresponding transparent polyamines are described, for example, in EP 0 725 1 00 and EP 0 725 1 0 1 . The laser printable intermediate layer may in particular comprise particles which cause a significant change in the transmittance. The particles may particularly comprise indium tin oxide (ιτο) and/or antimony tin oxide (yttrium oxide), preferably indium tin oxide (yttrium oxide). These particles preferably have a uniform distribution in the intermediate layer. Particularly interesting particles, especially those having a size in the range of d50 = 50 nm to d50 = 120 nm, are particularly preferred in the range of <150 = 80 nm to d50 = 100 nm. The number 値 is based on the average particle size (50% of the particles are smaller and 50% is larger), which can be determined in particular by P C S (photon correlation spectroscopy). For example, a Beckman Coulter N5 submicron particle size -13 - 201130684 analyzer can be used for this purpose. The ratio of the particles in the laser printable intermediate layer is preferably in the range of from 0.1% by weight to 0.5% by weight, based on the weight of the laser printable intermediate layer. • 〇〇 1 to 0.01% by weight. Particularly interesting layers are, in particular, laser printable layers which have a transmittance of preferably less than 10%, particularly preferably less than 5% 'and very preferably less than 1% after laser irradiation. . These can be achieved with the surprising black symbol in the registration mark. According to the third part of DIN 5 03 6 , the transmittance d R65 of the laser printable layer before laser irradiation is preferably at least 75%, particularly preferably at least 85% and very particularly preferably at least 90%. The plastic composition for the manufacture of a laser printable intermediate layer is described in particular in WO 2005/08495 5 Al, WO 2005/084956 A1 and WO 2006/09488 1 A1, and the nature and method of manufacture thereof are also described; And in particular, the laser printable plastic compositions described therein are incorporated in the disclosure of this application. A foil that can be used to make a laser printable intermediate layer for use in accordance with the present invention is available from Evonik Degussa GmbH under the trademark Trogamid® RS6047. The thickness of the laser printable intermediate layer is not subject to any particular limitation. Preferred embodiments of the license plate according to the present invention include, by way of example, a laser printable intermediate layer having a preferred thickness in the range of 0.2 mm to 2 mm, particularly in the range of 0.8 mm to 1.2 mm. The motor vehicle license plate additionally includes a protective layer disposed above the laser printable intermediate layer in such a manner that the position of the laser printable intermediate layer is translucent

S -14- 201130684 Between the retroreflective layer and the protective layer. The protective layer preferably has high transparency as well. The protective layer should have high scratch resistance and weathering resistance, so that the laser printable intermediate layer is protected from damage. Preferred plastics which can be used to make a protective layer are, in particular, polycarbonates, polyesters, polyamines, polyimides, polyurethanes, polyethers, polymethyl methacrylates and / or fluoropolymers, in which polymethyl methacrylate and / or fluoropolymers are particularly useful for the manufacture of protective layers. A particularly preferred protective layer covers a wide variety of compositions comprising polymethyl methacrylate and fluoropolymers such as polyvinylidene fluoride. With regard to polymethyl methacrylate which is preferably used for the production of a protective layer, reference is made to the above disclosure, and data on composition and molecular weight are correspondingly adapted thereto. The fluoropolymers are polymers which can be obtained by free radical polymerization of a stimulating unsaturated monomer, wherein at least one fluorine substituent is located at its double bond. Copolymers are also included herein. The copolymer may contain, in addition to one or more fluorine-containing monomers, other monomers copolymerizable with the fluorine-containing monomer. The fluorine-containing monomer is particularly chlorotrifluoroethylene, fluorovinylsulfonic acid, hexafluoroisobutylene, hexafluoropropylene, perfluorinated vinyl methyl ether, tetrafluoroethylene, vinyl fluoride and vinylidene fluoride. If an adjuvant or copolymer is used, the molecular weight can vary widely. The weight average molecular weight of the fluoropolymers is usually in the range of 100 200 to 200 000 g/mol, preferably in the range of 11 〇〇〇〇 to 17 克/mol, without any intentional limitation. . A particularly preferred mixture for the production of the protective layer comprises from 1% by weight to 90% by weight, in particular from 40% to 75% by weight, of polyvinylidene fluoride (pvdF) and from 90 to 10 -15 to 201130684% by weight, in particular 60 to 25% by weight of polymethyl methacrylate (PMM A ), wherein these numbers are based on the entire mixture. The most preferred PMMA contains a portion of the co-monomer (up to about 20% by weight, based on the amount of PMMA), such as butyl methacrylate or methyl acrylate, which improves processability. Preferred PVDFs can be used in the form of homopolymers and/or copolymers. The extrudable polymer mixture may comprise other polymers which are compatible with PVDF and with poly(meth)acrylates. These are in particular polycarbonates, polyesters, polyamines, polyimides, polyurethanes and polyethers. The protective layer may also contain additives conventionally known to those skilled in the art. These are in particular antistatic agents, antioxidants, dyes, flame retardants, tanning agents, light stabilizers and organophosphorus compounds (for example phosphites or phosphonates), pigments, weathering stabilizers and plasticizers. The additive preferably used to make the protective layer is a UV absorber. Particularly preferred are UV absorbers of benzotriazole type and hydroxyphenyl triazine. Extremely good is a UV absorber based on triazine. These UV absorbers are particularly durable and weather resistant. He also has superior absorption characteristics. The thickness of the protective layer can be in a wide range, but is preferably in the range of 20 micrometers to 500 micrometers, particularly preferably in the range of 40 micrometers to 100 micrometers. Foil which can be used to form the protective layer according to the invention is described in particular in EP-A-1 140 465, and the foil can be obtained commercially from Evonik Degussa GmbH under the trademark EUROPLEX® HC 99710. The individual layers of the license plate (especially the translucent retroreflective layer, the laser printable intermediate layer and the protective layer) can be interconnected in a known manner. For example

S -16 - 201130684, individual layers may be connected to one another via, for example, coextrusion or via a layer of adhesive, and individual layers may also be combined here by a variety of methods. For example, the laser printable intermediate layer and protective layer can be coextruded. The resulting composite can then be bonded to the retroreflective layer by an adhesive. Accordingly, the license plate of the present invention includes other layers or members in addition to the above-described layers. These are in particular layers of adhesive for interconnecting the layers. The motor vehicle license plate described above may also have been applied to the base layer, and the license plate may be easily detached from the base layer. For example, a pre-manufactured motor vehicle license plate can be supplied to a registered position in a form in which a pre-manufactured license plate having a retroreflective layer, an intermediate layer, and a protective layer has been applied to the base layer. At the registered location, the motor vehicle registration mark can be provided to the license plate in a simple manner by using a laser. The resulting finished license plate can be removed from the base foil and bonded to a lighting device such as a light guiding layer or luminescent foil on the motor vehicle. According to a preferred embodiment, the license plate can be attached to the optical conductor and/or the illuminating foil to illuminate the back of the license plate. The electrically activatable illuminating foil may be an electroluminescent foil activated by an alternating voltage in a known manner, which in the case of a motor vehicle license plate may be DC voltage available from the starting vehicle under the aid of a weight. produce. However, it is particularly preferable to use a foil having an organic light-emitting diode (known as an OLED foil) as an electrically activatable light-emitting foil, which has the advantage that it can be used by a vehicle that is launched from a very simple additional circuit. The DC voltage is operated. There is no need for an electronic drive for the electroluminescent foil and no special insulation is required. Another advantage of OLED foils is basically higher luminosity up to -17-201130684. According to a particularly good aspect, the license plate can be illuminated via an optical conductor. Optical conductors are described in particular in WO 2007/0 1 2306 or EP 1 477 3 68. The optical conductor has at least one light input region and at least one light output region. The term light output region here characterizes a region suitable for illumination by an optical conductor. Conversely, the light input region can receive light into the conductor such that the light guide layer distributes the input light throughout the light output region. The thickness of the photoconductive layer is preferably at least 1 mm, particularly preferably at least 2 mm. For example, light can be emitted via a structural effect on the light output region or via scattering particles (e.g., barium sulfate) present in the optical conductor such that the light output is distributed throughout the light output region. The ratio of the light output area to the light input area may here be at least 4, preferably at least 20 and particularly preferably at least 80. The light is usually directed in a direction approximately perpendicular to the direction of travel of the light, and the amount of light emitted therein depends on the amount of scattering particles in the plastic matrix and in accordance with the degree of structural effect on the surface. As this amount increases, the amount of light emitted also increases. This amount is therefore dependent on the size of the light output area. As the width of the optical conductor perpendicular to the light input region increases, the selected amount of scattering particles (especially barium sulfate) in the photoconductive layer also increases. The optical conductor preferably has superior mechanical and thermal properties. These properties specifically cover a Vicat softening point of at least 95 ° C according to ISO 306 (B50), a notched impact resistance NIR of at least 3.0 kJ/m 2 in accordance with ISO 180 at 20 °C ( Cantilever type 180/leA, 1.8 MPa), and an elastic modulus of at least 2000 MPa according to ISO 527-2. The size of the optical conductor is not subject to any particular limitation, but its area is preferably -18-201130684 to correspond to the area of the license plate to be illuminated, since a smaller optical conductor would result in poor license plate illumination, but a larger optical conductor would be required. Higher costs have no accompanying additional advantages. The thickness of the optical conductor is often determined by the particular technique used to illuminate the optical conductor. Particularly interesting optical conductors are those having a thickness in the range of 1 to 10 mm, particularly preferably 3 to 6 mm. Any illuminating device can be used as the light source for the optical input optical conductor. These are especially commercially available white heat bulbs and light-emitting diodes. In order to adjust the color of the registration mark to suit the law, a color layer may be applied to the face of the optical conductor and to the face of the light-emitting foil opposite the translucent retroreflective layer. The layer may in particular be designed in white or yellow, and the layer may be made using conventional thermoplastic plastics, examples being polyethylene, polypropylene, polystyrene and polymethyl methacrylate (PMMA). The color layer thickness can be chosen such that the layer stabilizes the license plate. The license plates can be attached to the optical conductors and the illuminating foil, respectively, in any known manner. For example, it is therefore possible to use a holder to connect the license plate to the optical conductor. Adhesive bonding can also be used to secure the license plate to the optical conductor. Particularly interesting licenses here are those which, once connected to the optical conductor (which are attached to the vehicle), cannot be separated from the optical conductor without being destroyed. An example of a method of achieving this is to use a preferred rupture position pattern, which is typically used in highway toll printing 〇 a license plate may be particularly advantageously equipped with a bar code. The motor vehicle registration mark has increased the protection against unauthorized use. For example, it may be possible to promote the simple and categorized classification of motor vehicles with licenses by introducing codes from the Wei'an authorities. For example, bar codes can be used specifically on license plates to provide specific information, such as the year, color, manufacturer, and model. A similar advantage can be achieved by providing at least one electronic circuit to the motor vehicle license plate. Preferred electronic circuits, particularly those known as RFID chips (radio frequency identification), can be read wirelessly. According to a particularly advantageous embodiment, the RFID chip can automatically transmit an identification signal. This type of circuit is installed in licenses, in particular by Hills Numberplates Ltd., and these are marketed under the e-Plate® trademark. The motor vehicle license plate can be made in any manner known to those skilled in the art. As noted above, the individual layers may be joined to one another via an adhesive or may be coextruded, and the individual methods are known per se. Information on the manufacture of individual layers and on the coextrusion process and the adhesive bonding method can be found in the above cited patent documents and in Ullmann's Encyclopedia of Industrial Chemistry, 5th Edition on CD-ROM, 1 997. A laser can be used to provide the symbol to the license plate. Commercially available laser systems can be used here. Advantageous lasers produce electromagnetic radiation having a wavelength of from 1 〇〇 to 3000 nm, preferably from 300 to 1 500 nm or from 1 900 to 2100 nm, and very particularly preferably from 800 to 1100 nm. According to a preferred embodiment, a laser having a wavelength of about 5 3 2 nm or 1 064 nm is used. The laser can be designed, for example, as a diode laser or a Nd:YAG laser type. The beam can be a pulsed or continuous (continuous wave) beam. In particular, but not limited to the invention, the laser is an argon laser having a wavelength of 48 8 nm and 514 nm, respectively having an ammonia-氖 wavelength of 5 43 , 63 3 and 1 150 nm. Laser with 3 3 7

S -20- 201130684 nm-wave nitrogen laser with a hydrogen laser of 2600 to 3000 nm wavelength '氪La's with a wavelength of 330 to 360 nm or 420 to 800 nm' with a wavelength of 694 nm (Rubin) laser 'KTP laser with 532 nm wavelength (double frequency Nd:YAG laser)' Nd : YAG laser with three times the wavelength of 355 nm or four with a wavelength of 266 nm Double frequency Nd: YAG laser, Alexandrite laser with 755 nm wavelength and YAG laser. The YAG laser has a ji-ming-stone garnet crystal rod as a laser medium. The rod has been doped with a rare earth metal such as yttrium (Nd: YAG, wavelength 1060 nm), bait (ErYAG, wavelength 2940 nm), yttrium (Ho: YAG, wavelength 2070 nm), yttrium (Tm, wavelength 2 波长) 74 nm) or chromium ((:1*), or a combination thereof. Other examples are 1'111: 丫1^ laser or Ho: YLF laser, which uses different laser media and likewise has about 2000 nm Wavelength. It is also possible to use a high power diode laser with a wavelength of 800 to 1000 nm and an excimer laser with a wavelength of 193 nm or 352 nm. In the case of an excimer laser, special Reference may be made to an F2 excited atomic laser having a wavelength of 157 nm, an ArF excited atomic laser having a wavelength of 193 nm, a KrCI excimer laser having a wavelength of 222 nm, and a KrF excitation having a wavelength of 248 nm. State atomic laser, XeCI excited atomic laser with a wavelength of 308 nm and XeF excited atomic laser with a wavelength of 351 nm. The laser can be a solid state laser (example is Rubin laser or Nd : YAG laser), semiconductor laser, or gas laser (eg argon laser, krypton-helium laser or ammonia laser). The laser used can often be operated with a power level of 1 to 1200 watts (preferably 10 to 500 watts, -21 - 201130684 and particularly preferably 12 to 100 watts). The focus size of the laser beam determines the resolution of the imprint method. The focal radius is often from 0. 05 to 1 mm, preferably from 0.1 to 0.4 mm. Figure 1 illustrates a specific embodiment of a motor vehicle license plate (1) according to the present invention, but without intending to be limited. The version comprises a semi-transparent retroreflective foil (2). The foil (2) may, for example, comprise a silver-plated glass hemisphere' to obtain retroreflective properties. The laser printable intermediate layer (3) has been applied thereto This layer (2) has been formed of a transparent polymer and ITO particles. To protect the license plate, the protective layer (4) has been applied as an outer layer, and in this embodiment is formed via a Plexiglas® HC foil. An optical conductor (5), such as a diffuser plate (such as Piexigias® DF 7H 22), has been applied to the back side of the translucent retroreflective layer (2) in the license plate (1). The optical conductor (5) can evenly illuminate the license plate (1). The specific example described in Figure 1 has color (6) on the opposite side of the optical conductor from the translucent retroreflective layer (2). Illumination means (7) may be used to input light into the optical conductor (5) to provide uniform illumination of the license plate" SMD LEDs can be used for this purpose. [Schematic Description of the Drawings] Figure 1 illustrates a specific example of one of the motor vehicle license plates (1) according to the present invention.

S -22- 201130684 1 : Motor vehicle license plate 2 : Translucent retroreflective layer 3 : Laser printable intermediate layer 4 : Protective layer 5 : Optical conductor 6 : Color layer 7 : Lighting device -23-

Claims (1)

201130684 VII. Patent application scope: 1. A motor vehicle license plate (1) comprising at least half of a transparent retroreflective layer (2), characterized in that the license plate (1) has at least one transparent laser printable intermediate layer (3) And a transparent protective layer (4), wherein the intermediate layer (3) is disposed between the protective layer (4) and the semi-transparent retroreflective layer (2). 2. For a licence to apply for a patent scope, item 1, wherein the laser printable intermediate layer (3) comprises a plastic containing nanoparticle. 3. A license plate as claimed in claim 2, wherein the plastic present in the intermediate layer (3) comprises polyamine. 4. The license plate of claim 1 or 2, wherein the intermediate layer (3) has a thickness in the range of 0.2 mm to 2 mm. 5. A license plate as claimed in claim 1 or 2, wherein the protective layer (4) comprises polymethyl methacrylate. 6. The license plate of claim 1 or 2, wherein the protective layer (4) comprises polyvinylidene fluoride (PVDF). 7. The license plate of claim 1 or 2, wherein the protective layer (4) comprises a blend comprising polymethyl methacrylate and polyvinylidene fluoride. 8. The scope of claim 1 or 2 A license plate wherein the thickness of the protective layer (4) is in the range of 20 micrometers to 500 micrometers. 9. A license plate as claimed in claim 1 or 2, wherein the license plate is connected to an optical conductor (5) or a light-emitting foil which has been disposed on the back side of the semi-transparent retroreflective layer (2). S -24- 201130684 1 〇 · Rushen has been set on this: on. 1 1. The thickness of the application 5) is 12. If it is applied to bond the f piece. 1 3 · If you apply for the license | 1 4 · Such as Shen) has been equipped with a strip fil 1 5 . Such as Shen Hao) contains at least -16. Such as the application of RFID chips. 1 7. If the application is voluntarily passed the license of the scope of the patent application, the color layer (6) the back of the optical conductor (5) and / or the back of the light-emitting foil, please apply for the license of item 9 of the patent scope, The optical conductor (in the range of 1 to 1 〇 mm. The license of the ninth patent scope, wherein the adhesive illuminating (!) has been used to connect to the optical conductor and/or the luminescent foil, please refer to item 9 of the patent scope a license plate in which the holder (1) has been connected to the optical conductor (5) and/or the license plate of the illuminating foil of claim 1 or 2, wherein the license plate (1 ί ° patent scope 1 or 2) The license, wherein the license (1 - circuit. δ 靑 patent scope 1 or 2 of the license, wherein the circuit is the license of the patent scope 1 or 2, wherein the R FID crystal i identification signal.