DE102011007349A1 - Labeling substrate e.g. transparent container, comprises depositing luminescent dye as first identification feature in transparent oxide marker layer, and setting roughness of marker layer as second identification feature - Google Patents

Abstract

The method comprises depositing a luminescent dye such as a fluorescent dye as a first identification feature in a transparent oxide marker layer or in an oxidic functional layer located on a surface of a substrate or on a layer located on the substrate surface, where the deposition of the marker layers or functional layers is carried out under atmospheric pressure by chemical vapor deposition using a plasma, and setting a roughness of marker layer or functional layer as a second identification feature by variation of parameters of the chemical vapor deposition. The method comprises depositing a luminescent dye such as a fluorescent dye as a first identification feature in a transparent oxide marker layer or in an oxidic functional layer located on a surface of a substrate or on a layer located on the substrate surface, where the deposition of the marker layers or functional layers is carried out under atmospheric pressure by chemical vapor deposition using a plasma, and setting a roughness of marker layer or functional layer as a second identification feature by variation of parameters of the chemical vapor deposition. A dose of a precursor for the preparation of the oxide layer is varied as the second identification feature. A droplet size of a precursor is set as a parameter, where the working gas or the plasma is fed as an aerosol. The droplet size of the precursor is set as the parameter, where the aerosol is formed by spraying into a working gas stream with the working gas. The droplet size is adjusted by the selection of a size of a nozzle with which the precursor is supplied, or by the variation of a throughput of the working gas stream. The precursor dosage is set by the selection and parameters of a metering pump. As the parameter a number of cycles is varied, in which the plasma is passed over the surface. The transparent marker layer or the functional layer is provided with a structure, in a further step, for producing a third identification feature by thermal local destruction.

Description

The invention relates to a method for identifying a substrate.

Product piracy is a problem that causes significant economic damage to manufacturers of original products, especially for high quality products (cosmetics, medicines, watches, lenses, car windows, etc.). Especially with counterfeit drugs, the consumer is seriously affected because counterfeit drugs can be ineffective at best and in the worst case dangerous or even life-threatening. For such product groups, therefore, there is a need for effective protection against plagiarism.

The labeling of product packaging, such as container glass or plastic packaging, by means of laser marking has long been known. This type of marking is easily verifiable by eye, but also relatively easy to fake.

Furthermore, the admixture of fluorescent dyes in polymers for the production of device housings and components is known. With these dyes, it is possible to set a defined color point or color value, which can be read by means of a detector. With different colors thereby different production times are coded.

The invention has for its object to provide a method for identifying a substrate, with which an improved protection against plagiarism is achieved.

From the post-published DE 10 2010 022 701 a method is known for the identification of a substrate in which at least one luminescent dye is deposited in at least one transparent marker layer or in at least one functional layer on a surface of the substrate or on an on-surface layer as a first identification feature, wherein the transparent marker layer or the functional layer is provided in a further step for generating a second identification feature by local destruction, in particular thermally, with a structure.

The object is achieved by a method having the features of claim 1.

Advantageous embodiments of the invention are the subject of the dependent claims.

In a method according to the invention for identifying a substrate, at least one luminescent dye is deposited in at least one transparent oxidic marker layer or in at least one oxide functional layer on a surface of the substrate or on a surface layer as a first identification feature. The deposition of at least one of the marker layers or functional layers takes place by means of chemical vapor deposition using a plasma. As a second identification feature, a roughness of the marker layer or functional layer is set by means of variation of parameters of the chemical vapor deposition. The roughness can be varied, for example, between 1 nm and about 25 nm.

The first identifier may encode desired information about the selected luminescent dye. Luminescent dyes emit light as a result of external excitation, for example by irradiation with light of the visible spectrum or in the ultraviolet range in the case of photoluminescence. Photoluminescent dyes are in particular phosphorescent and / or fluorescent. Both fluorescence and phosphorescence are forms of luminescence (cold glow). Fluorescence ends relatively quickly after the end of irradiation (usually within one millionth of a second). In the case of phosphorescence, however, afterglow can occur over fractions of a second up to hours.

The deposition of at least one of the marker layers or functional layers preferably takes place by means of chemical vapor deposition using a plasma. Such a process is commonly referred to as PACVD (plasma activated chemical vapor deposition). Such processes occur both in low pressure and under normal pressure conditions.

The deposition is preferably carried out so that a plasma jet is generated from a working gas, wherein at least one precursor material is supplied to the working gas and / or the plasma jet and is reacted in the plasma jet. At least one reaction product of at least one of the precursors is deposited on the substrate as a marker layer or functional layer. The dye is either dissolved or dispersed in a liquid medium or is contained in nanozeolites. The dissolved or dispersed dye or nano-zeolites with the dye are fed to the working gas or the plasma jet separately or together with the precursor.

When dispersing in particular chemically stable organic dyes used. The dispersed dye is preferably metered into the working gas or the plasma jet by means of a peristaltic pump.

Particularly preferably, the deposition is carried out at atmospheric pressure, in particular as a normal pressure plasma process. By working at atmospheric pressure, a time-consuming process step of evacuating a process chamber as well as apparatuses for vacuum generation, such as vacuum pumps and process chamber are saved in a particularly advantageous manner. As a result, the method can be integrated into a process chain without great effort, which involves production and compensation of the substrate.

Alternatively or additionally, at least one of the marker layers or functional layers can be deposited by means of a sol-gel process, by means of a flame or electrochemically. In the sol-gel coating, a precursor is dissolved in a solvent and admixed with a catalyst, for example an acid. This sol is applied to the surface to be coated and dried, so that the crosslinking begins. The resulting network is called a gel. After drying, a temperature of the layer, for example at a temperature of at least 300 ° C, take place, wherein the layer is completely crosslinked. The layer thus produced is mechanically stable.

The sol-gel coating may be followed by a previous chemical vapor deposition from the plasma.

The roughness of the marker layer or functional layer, which is set as the second identification feature, is imperceptible to the naked eye, but can be detected by means of surface-sensitive methods, for example by means of interference microscopy, Atomic Force Microscopy (AFM) or profilometry.

As a parameter for adjusting the roughness, a dose of the precursor for producing the oxide layer can be varied, which is supplied to the plasma or a working gas from which the plasma is formed.

Likewise, as a parameter, a droplet size of the precursor can be adjusted, which is supplied to the working gas or the plasma as an aerosol or forms an aerosol by spraying into a working gas stream with the working gas.

The droplet size has, in addition to the influence on the morphology of the deposited layer, also an influence on the distribution of the dye in the layer. This can be detected by fluorescence microscopy.

The droplet size can be adjusted for example by selecting a size of a nozzle, with which the precursor is supplied or by varying a flow rate of the working gas stream.

Also, as a parameter, a number of passes may be varied in which the plasma is passed over the surface. The higher the number of passes selected, the higher the resulting surface roughness.

Likewise, as a parameter, the precursor dosage can be set by the selection and parameters of a metering pump.

The transparent marker layer or the functional layer can be provided with a structure by local destruction, in particular thermally, in a further step for producing a third identification feature.

In this case, for example, one or more alphanumeric characters, symbols or logos or one- or two-dimensional barcodes can be introduced into the dye-containing layer. The combination of the identification features results in a particularly high security against counterfeiting.

Special luminescent dyes are not visible in the absence of UV radiation or at low intensities and accordingly do not affect the appearance of the product. Nor is the third identification feature in the luminescent layer recognizable under such conditions. Only upon excitation of the luminescent layer, for example by irradiation with ultraviolet light, for example from a scanner, both identification features are visible. The scanner is then preferably designed so that it can not only make the identification features visible, but also recognize them.

The local destruction takes place by thermal entry into the layer containing the luminescent dye. The heat input raises the temperature in a locally limited area above the decomposition temperature of the luminescent dye and destroys the luminescence property locally.

The local destruction preferably takes place by means of a laser. This simplifies the labeling, since the laser is usually used anyway for labeling or engraving. With the laser is a pinpoint thermal destruction of the dyes possible. The laser can be focused so that the dye in the marker layer or functional layer can be destroyed even if there are one or more other layers over it which were later deposited without damaging these further layers. If necessary, the laser can be tuned to an absorption wavelength of the respective dye.

Likewise, the local destruction can be done by means of a flame or a plasma. Particularly suitable for this purpose are atmospheric-pressure plasma jets which can be positioned at high spatial resolution.

Similarly, the local destruction can be done by means of a plasma micro-stamp. For this plasma sources are used, in which so-called cold discharges ignite in cavities that are temporarily formed between a printing plate (stamp or roller) and the surface of the coated substrate. These treat the surface locally. These discharges are dielectric barrier and high frequency discharges.

As a luminescent dye is preferably a fluorescent dye, in particular an organic fluorescent dye used, since it can be destroyed particularly easily by heating. Preferably, such a fluorescent dye is used which emits light only when excited with an aid such as UV light and otherwise invisible.

Alternatively to a luminescent dye, a thermochromic and / or electrochromic and / or photochromic and / or gasochromic switching dye can be deposited. Switching dyes change their color depending on a temperature (thermochromic), an electric field or a current flow (electrochromic), an excitation with light, in particular light of certain wavelengths (photochromic) or in the presence of a certain gas (gasochrom).

Similarly, loaded with the dye Nanozeolithe can be deposited. Nanozeolites are nanoscale particles of a species-rich family of chemically complex silicate minerals, the zeolites. These minerals can store up to about 40 percent of their dry weight of water, which is given off when heated. In damp air, the water can be absorbed without affecting the structure of the mineral. Zeolites are formed from a microporous framework structure of AlO ₄ and SiO ₄ tetrahedra. The aluminum and silicon atoms are interconnected by oxygen atoms. This results in a structure of uniform pores and / or channels in which substances can be adsorbed. Zeolites can therefore be used as sieves, since only those molecules which have a smaller kinetic diameter than the pore openings of the zeolite structure adsorb in the pores. In the present case, the dyes are embedded in the pores of the nanozeolites.

In particular, organic fluorescent dyes are suitable, since they are temperature-sensitive and can easily be destroyed thermally.

In a preferred embodiment, a transparent or translucent substrate, in particular an optical glass, for example a lens, in particular a spectacle lens, at a localized location of the substrate with the first, second and optionally third identification feature is characterized.

In a further preferred embodiment, a transparent or translucent substrate, for example a watch glass or a car window, is identified at a locally limited location of the substrate with the first, second and optionally third identification feature.

In a particularly preferred embodiment, a transparent or translucent substrate, in particular a container with the first, second and optionally third identification feature is characterized. The substrate may for example consist of glass or a transparent plastic.

In this case, the deposition of the marker layer or the functional layer can take place at the end of a process for producing the container, for example with a manufacturer of the container. The local destruction can then take place in a process for filling the container, not necessarily at the manufacturer of the container, but at the manufacturer of a product that is filled into the container.

The first identifier is used, for example, by selecting the luminescent dye to code a production lot or a production date of the container. Different colors of the luminescent dye can, for example, code different production batches. The second identification feature, the roughness of the layer, can also serve to code information during the production of the container. By means of the third identification feature, a product batch or a filling date of a product filled in the container can then be coded. This allows a follow-up of the production chain.

The marking of the container with the identification features can be done for example on the ground or on the vessel walls.

Embodiments of the invention are explained in more detail below with reference to drawings.

Show:

1 a surface profile of an atmospheric pressure plasma coated substrate after nine passes, and

2 a surface profile of an atmospheric pressure plasma coated substrate after 15 passes.

Using an atmospheric pressure plasma, a silicon dioxide layer was applied as a marker layer to a glass substrate. For this purpose, a silicon-containing precursor, for example hexamethyldisiloxane (HMDSO), was fed to the plasma or the working gas from which the plasma was formed. By adding nanoparticles with fluorescent dyes to the precursor particles of this dye were incorporated into the matrix of the marker layer. Nine runs were performed in which the plasma was passed over the surface of the substrate. As a result of this PACVD process (plasma activated chemical vapor deposition), a layer with a thickness of approximately 100 nm was achieved. A roughness of the layer is about 10 nm. 1 shows a surface profile of the layer.

If 15 passes are carried out instead, the result is a layer thickness of about 170 nm with a roughness of about 20 nm. The surface profile of this layer is in 2 shown.

The deposited dye can be used as a first identification feature. The roughness of the layer can be used as a second identification feature.

The roughness of the marker layer or functional layer, which is set as a second identification feature, can be detected by means of surface-sensitive methods, for example by means of interference microscopy, atomic force microscopy (AFM) or profilometry.

As a further or alternative parameter for adjusting the roughness, a dose of the precursor for producing the oxide layer can be varied, which is supplied to the plasma or a working gas from which the plasma is formed.

Likewise, as a parameter, a droplet size of the precursor can be adjusted, which is supplied to the working gas or the plasma as an aerosol or forms an aerosol by spraying into a working gas stream with the working gas.

The droplet size can be adjusted for example by selecting a size of a nozzle, with which the precursor is supplied or by varying a flow rate of the working gas stream.

The plasma torch was operated at a power of 400W. The substrate was moved at a distance of 10 mm from the burner at a travel speed of 100 mm / s. The plasma burner was meandered over the substrate, the grid spacing was 3 mm. TINOPAL OB from Ciba Specialty Chemicals Basel was chosen as the fluorescent dye.

The thus-coated substrate was irradiated with a laser, whereby the laser was rastered over the surface of the substrate. As a result, the fluorescence effect of the layer was destroyed locally in the area scanned by the laser, thus creating a third identification feature. In this case, a laser of wavelength 355 nm was used with a focus diameter of 20 microns to 100 microns.

Another dye, in particular a luminescent dye and / or a thermochromic and / or electrochromic and / or photochromic and / or gasochromic switching dye, can be deposited as the first identification feature in the marker layer or in a functional layer.

The first identification feature can be destroyed by other means, in particular thermally. For example, a flame or a plasma, in particular a plasma microstamp, can be used for this purpose.

Similarly, loaded with the dye Nanozeolithe be deposited in the marker layer or functional layer.

The second identification feature can be set both by varying the number of passes and thus the layer thickness and by varying the Precursordosierung or by varying the droplet size of the precursor or by varying several of these parameters simultaneously.

The deposition may alternatively with the atmospheric pressure plasma method with other methods, for example by means of chemical vapor deposition using a flame, by means of a sol-gel process or by means of electrochemical deposition.

The sol-gel coating may be followed by a previous chemical vapor deposition from the flame or the plasma.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102010022701 [0006]

Claims (11)

Method for identifying a substrate, wherein at least one luminescent dye is deposited in at least one transparent oxide marker layer or in at least one oxide functional layer on a surface of the substrate or on a surface layer as a first identification feature, the deposition of at least one of Marker layers or functional layers by means of chemical vapor deposition using a plasma, wherein as a second identification feature, a roughness of the marker layer or functional layer is adjusted by means of variation of parameters of the chemical vapor deposition. A method according to claim 1, characterized in that as a parameter, a dose of a precursor for producing the oxide layer is varied, which is supplied to the plasma or a working gas from which the plasma is formed. Method according to one of claims 1 or 2, characterized in that a droplet size of a precursor is set as a parameter, which is supplied to the working gas or the plasma as an aerosol. Method according to one of claims 1 or 2, characterized in that a droplet size of a precursor is set as a parameter, which forms an aerosol by spraying into a working gas stream with the working gas. Method according to one of claims 3 or 4, characterized in that the droplet size is adjusted by selecting a size of a nozzle with which the precursor is supplied or by varying a flow rate of the working gas stream. Method according to one of claims 1 or 2, characterized in that the Precursordosierung is set by the selection and parameters of a metering pump. Method according to one of the preceding claims, characterized in that as a parameter a number of passes is varied in which the plasma is passed over the surface. Method according to one of the preceding claims, characterized in that the transparent marker layer or the functional layer is provided in a further step for generating a third identification feature by local destruction, in particular thermally, with a structure. Method according to one of the preceding claims, characterized in that the deposition takes place under atmospheric pressure. Method according to one of the preceding claims, characterized in that a fluorescent dye is used as the luminescent dye. Method according to one of the preceding claims, characterized in that a transparent or translucent substrate, in particular a container, is characterized.

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