EP1230094B1 - Method for applying coloured characters on a data storage medium which is preferably made from plastic and data storage media according to said method - Google Patents

Abstract

The invention relates to a method for applying coloured characters on a data storage medium, which is preferably made from plastic, by means of a laser system, whereby latent pigments are applied in at least one surface layer and/or surface adjacent layer. The absorption characteristics of said latent pigments can be changed by energetic stimulation. Said stimulation occurs in those areas of the surface of the data storage medium allotted to the characters, by means of laser radiation in the IR/visible region, whose energetic stimulation is such that a colour change occurs in said latent pigments. After said colour change in the laser irradiated latent pigments, the latent pigments which have not been stimulated by laser irradiation are irradiated by light in the UV wavelength region, whose energetic stimulation is such that the pigments, irradiated by this means, are rendered colourless.

Description

The invention relates to a method for applying colored characters to a Disk preferably made of plastic according to the preamble of claim 1 and Claim 2 and a data carrier produced by this method according to claim Third

Data carriers, preferably made of plastic, are in various forms as chip cards for example in the form of credit cards, access authorization cards, bank cards and the like are known and are used in a wide variety of service areas used. The data carriers are available for the various applications mostly an integrated circuit on the front, the so-called chip module and additionally or alternatively a magnetic stripe on the back of the data carrier. Chip module as well as magnetic strips contain information electronically Type required for the application of the data carrier in the various service areas are necessary. The information on these components is only included Readable with the help of specially suitable devices. To map disks in addition, to be able to do it visually, it is desirable and usual, special data related to the cardholder readable on the Apply card. This data in the form of letters, numbers, pictures and / or Samples must be designed in such a way that they are as much as possible against counterfeiting and falsification are protected. On the other hand, protection against adulteration should be easy and inexpensive to manufacture, since the data carriers are mass-produced items is.

Methods for applying such characters to data media can be as follows different ways of working. The application of black According to the prior art, characters are made by using a laser system Letters, numbers or patterns in the surface of the corresponding Disk to be burned in. The color change goes with carbonization associated. Colored markings cannot be created in this way. For colored characters, it is rather necessary to use u. U. several on top of each other horizontal colored layers, which are then in a second process step up to the personalization of the data carriers by a laser system the depth at which the desired colored layer within is removed the disk is arranged.

It is known that certain pigments irreversibly change their color under the influence of light radiation.
For example, DE 695 04 238 T2 discloses pigments which change their optical properties, in particular their color, when irradiated with laser light. However, there is no indication in this patent that latent pigments are used which change from almost colorless or weakly colored to the colored state by irradiation with laser light in the IR (infrared) and / or visible range. Fading of latent pigments with light in the UV range (ultraviolet range) is also not described in DE 695 04 238 T2.

EP 0 190 997 A2 mentions a film which is produced using 1,4-diketo-3,6-di-parachlorophenyl-pyrrolo- [3,4-c] pyrrole pigments was produced. at When this film is irradiated with an Nd: YAG pulse laser, black lettering is created with good contrast. First of all, these are not latent ones Pigments, since the film has a red color from the start, and secondly only achieved a blackening. So it is a carbonization process.

DE 39 08 312 A1 describes diketopyrrolopyrroles which crystallize out Include solvents and become highly fluorescent. at the higher temperatures the solvent is released again and thus the Fluorescence abolished. With these diketopyrrolopyrroles there is therefore no light radiation caused color change from colorless or slightly colored to colored possible.

DE 39 01 988 A1 describes a chemical compound which crystallizes from organic solvents in an orange modification and which, when heated, converts to a yellow modification.
Since there is a colored initial modification here, it is not a latent pigment. This means that no color change from colorless or slightly colored to colored is possible here either.

DE 39 17 294 A1 lists additives that are used in the IR and / or UV spectral range have a high absorption capacity. Through these aggregates labeling by means of IR and / or UV laser radiation is possible, however no latent pigments are used, but only that the Additives with pigments and / or dyes can be colored as desired.

In JP-A-08 187 939 becomes a laminated magnetic stripe card and a method of making it described, which consists of several layers. A laser beam in the IR wavelength range is through the transparent, for the wavelength of the laser beam permeable, protective layer of such a magnetic stripe card on the infrared absorbing Layer of such a magnetic stripe card forwarded. In this infrared absorbing Layer contains an infrared absorbing agent which is used in the absorption of infrared Laser light reacts exothermically. Light energy is thus in this infrared absorbing layer converted into thermal energy. This thermal energy ensures that in the, under the arranged infrared absorbing layer, heat-sensitive color layer Dye developed a color. After that, the entire surface of the Magnetic stripe card irradiated with UV light. Here the exothermic reaction of the infrared goes absorbent lost and afterwards the heat-sensitive layer cannot more their color can be changed by a laser in the IR wavelength range.

EP-A-0 296 289 describes a diazo imaging material to generate multi-color images using a Variety of infrared rays with different Wavelengths. This photosensitive material has a variety capsules that are meltable by heat and that Contain infrared absorbent. After imaging is done the material is irradiated with UV light to fix the pictures.

Finally, an organic material is known from EP 0 327 508 A2 which is used for an a bleachable additive consisting of at least one azo and / or indanthrone pigment and secondly a non-bleaching compound consisting of at least one inorganic and / or organic pigment and / or a polymer-soluble dye. So there is no latent Pigment but a combination of a bleachable fabric and a non-bleachable pigment used. To create a contrast between one To ensure bleached and unbleached area, it is with this material necessary to cover the non-bleachable pigment. So the user is limited to dark shades for covering the non-bleachable pigment.

With regard to the protection against counterfeiting, the methods mentioned are ex post Manipulation of the characters relatively unsatisfactory, since of course the authorized one Personalization of the card by, for example, a combination of numbers and Letters at any later time using a suitable laser system an unauthorized change to this data can follow. Counterfeit protection to increase, various possibilities have become known Security features such as B. readable with infrared light inside the disk card embedded encodings, holographic storage methods and the like to be placed on the card. Such techniques have the major disadvantage that on the one hand they cannot be checked without complex aids and on the other hand of course, manipulation of the characters to personalize the cards can be made.

The invention is therefore based on the object of a method for application to provide colored characters on data carriers, preferably made of plastic, that is simple and inexpensive and, moreover, unprecedented security against forgery against unauthorized manipulation of the data on a data carrier provides legible information.

This object is achieved in that in the inventive Process in a surface layer or near-surface layer of the data carrier introduced latent pigments, in which a The absorption behavior of the pigments is changed on the markings provided for the characters Steep the data carrier energetically by laser radiation be stimulated that the pigments change color and that after the color change of the irradiated latent pigments that are not caused by laser radiation excited pigments by irradiation with light waves in the UV wavelength range energetically stimulated in such a way that Pigments a colorlessness of the pigments is brought about.

In addition, the object is achieved in that in a first method step into a surface layer or near-surface layer of the data carrier introduced latent pigments, in which a change due to energetic stimulation the absorption behavior of the pigments takes place on the not for the character representation provided points by irradiation with light waves in the UV wavelength range energetically stimulated in such a way that Pigments a colorlessness of the previously latent pigments is brought about and that in a second step of the process for the display of characters intended locations in the surface layer arranged latent pigments energized by laser radiation in such a way that the latent ones Pigments change color.

Because the latent pigments are inexpensively combined in different ways Letting data media be implemented results in a particularly cost-effective way Manufacturing process for the colored labeling or marking of a data carrier such as a chip card, in which the previously common multi-layered, complex Structure with different layers of paint can be omitted. With the latent Pigments are, for example, diketo-pyrrolo-pyrroles, which result from a Repigment thermal excitation in diketo-pyrrolo-pyrrole system dyes. In In the unirradiated state, such latent pigments are mostly colorless or weak coloured. Only through energetic stimulation are the pigments activated and so the desired color change is brought about to a strong, clearly visible color. This energetic suggestion can be used to apply numbers and letters easiest to do with the help of a laser system. Is a color change as a result of laser light irradiation, this process is irreversible, i. H. there is no longer a subsequent change in the pigments by further irradiation possible. With regard to counterfeit security, it should also be noted that the latent pigments can be arranged inside the data carrier, if one Irradiation through overlying transparent protective layers is possible. Consequently the colored markings made by color change cannot be Eliminate later by mechanical or chemical processing without the disk to make it unusable as a whole.

To counterfeit security with the first method step according to the invention The colored characters produced on a data carrier are added to the laser radiation the second downstream method step connected to a data carrier.

The second process step described makes the property of latent pigments take advantage of the fact that through different energetic stimulation a different one Color change of the latent pigments can be brought about. Is thus after the Application of the colored characters, letters or other patterns of the data carriers Irradiated with UV light over a large area, they have not yet changed energetically affected latent pigments in their colorless status. This conversion is as irreversible as the application of colored characters described above with the help of laser radiation. Thus, all are for a labeling option provided latent pigments after carrying out the second process step been converted and therefore unchangeable, so another possible radiation to apply additional characters on the data carrier by means of of a laser system or by other energetic stimulation Result would result in a possible destruction of the data carrier. The second step of the process increases the security against forgery on the data carriers applied colored characters thus increased to an extent that was previously the case was technically not possible. In addition, of course, are those already described above Advantages of easy embedding of the latent pigments in the data carrier body possible.

Of course, it is also conceivable to reverse the method steps described Order. In a first process step, the Surface layer of the data medium introduced latent pigments on the not for the characters provided by irradiation with light waves energetically stimulated in the UV wavelength range in such a way that Pigments a colorlessness of these pigments is brought about. After that in a second process step, those provided for the character display Put latent pigments arranged in the surface layer through Appropriate laser radiation energized so that with these pigments a color change takes place in a visually clearly visible color.

The invention also relates to one according to the invention described above Processed data carrier with a data carrier body, in which to solve the task latent pigments in at least one sub-layer of the Data carrier body are arranged so that radiation by means of a laser system and UV radiation energetically stimulates the latent pigments causes.

The latent pigments can correspond to the features of the subclaims 4 to 8 in different ways in or on the disk body be arranged.

According to an advantageous embodiment, it is possible, for example, to use the latent ones Arrange pigments in a cover film applied to the outer surface of the data carrier. Such films can be easily and inexpensively produce and connect to the disk body just as inexpensively. Advantageous it is moreover if the foils provided with the latent pigments additionally is attached to the data carrier with a cover film covering this, so that the layer provided with the latent pigments has a direct mechanical Access is withdrawn.

In addition, it is conceivable to incorporate the latent pigments into a coating system, wherein the coating system, for example, a paint application or a Adhesion promoter order can provide during the production of data carriers. The Paint or adhesion promoter is applied in the usual way by sieve, Offset, pad printing or corresponding roller application, whereby of course a full surface a partial application of the lacquer is also conceivable, so that only certain ones Areas of the data carrier surface for one according to the invention Processed colored marking can be provided.

The latent pigments can also be in an overlay layer and / or in a through the overlay layer covered layer close to the surface.

An alternative way of attaching the latent pigments to a disk sees before, the material of the data carrier before the shaping process for the data carrier body, for example by injection molding, to be enriched with the latent pigments. The entire card body can be enriched with the latent pigments or it can be determined with the help of multi-component injection molding technology Parts of the carrier body from the enriched with the latent pigments Material are made.

All of the above-described possibilities of data carrier construction are simple and an inexpensive way to apply the latent pigments that are needed colored characters on data carriers are necessary to implement in or on the data carrier.

Signs are not just letters, numbers, special characters, logos, etc. to understand, but also patterns, pictures or photographs.

Exemplary embodiments of the data carriers according to the invention are described below of sectional views of the disk body explained in more detail.

Figur 1

einen Querschnitt durch einen aus mehreren Schichten im Compound-Verfahren hergestellten Datenträgernkörper und

Figur 2

einen Querschnitt durch einen im Spritzgussverfahren hergestellten Datenträgernkörper und

Figur 3

ein schematisches Diagramm des Absorptionsverhaltens eines latenten Pigmentes in Abhängigkeit der Wellenlänge des Lichtes, mit dem dieses bestrahlt wird.

Figur 4

eine Strukturformel für ein Beispiel eines latenten Pigments: N,N'-bis-iso-pentoxycarbonyl-1,4-diketo-3,6-di-(chlorophenyl)pyrrolo[3,4-c]pyrrol

Figur 5

eine Strukturformel für ein Beispiel eines Pigmentes: 1,4-diketo-3,6-di-(chlorophenyl)pyrrolo[3,4-c]pyrrol

It shows:

Figure 1

a cross section through a data carrier body made of several layers in the compound process and

Figure 2

a cross section through a data carrier body produced by injection molding and

Figure 3

a schematic diagram of the absorption behavior of a latent pigment as a function of the wavelength of the light with which it is irradiated.

Figure 4

a structural formula for an example of a latent pigment: N, N'-bis-isopentoxycarbonyl-1,4-diketo-3,6-di- (chlorophenyl) pyrrolo [3,4-c] pyrrole

Figure 5

a structural formula for an example of a pigment: 1,4-diketo-3,6-di- (chlorophenyl) pyrrolo [3,4-c] pyrrole

The data carrier body shown in FIG. 1 in the form of a chip card essentially consists from two core foils 1 and 2, on the top and bottom of the disk transparent cover films 3, 4, 5 and 6 are applied. In the illustrated An embodiment is located between the cover films 5 and 6, a coating layer 7, consisting of an adhesive or varnish, in which the latent pigments are implemented. The lacquer or adhesive layer 7 is thus on the one hand protected under the immediate surface of the disk, but can be protected by Laser irradiation through the transparent cover film 6 are energized, so that an energetic stimulation of the latent pigments is possible, which changes color of the pigments at the irradiated areas.

As an alternative to the laser beam source, another high-energy, highly concentrated Light source can be used that emits light in the visible or IR range. It is it may be necessary to use optical filters that have interfering wavelengths eliminate.

Lamps or UV lasers can be used as light sources for the UV radiation. If necessary, interfering wavelengths of these light sources with optical Filtered out.

On the opposite surface side of the data carrier is analog on the one hand the structure described above between the cover sheets 3 and 4, a coating layer 8 arranged, moreover is located between the inside Cover film 4 and the core film 1, a further coating layer 9, so that in this Structure in the coating layers 8 and 9 different latent pigments can be implemented to produce different colored characters in this way to be able to.

Alternatively, the latent pigments can also be in at least one cover sheet 3, 4, 5, 6 be included.

Of course, it is also conceivable in the material of the core films 1, 2 or the cover films 3, 4, 5, 6 introduce latent pigments, and then to a disk body to squeeze. When the latent pigments are located in the core films 1, 2 are, it is also possible to partially or completely dispense with cover foils.

The data carrier body shown in FIG. 2 is an injection molding technique produced variant of a chip card. The chip card body consists of essentially of a core layer 11 with over it on both flat sides of the carrier body arranged film layers. The data carrier body of this design variant is manufactured in the so-called 2K injection molding process and has one second core layer 12 enriched with latent pigments. Above these two Core layers 11 and 12, further cover foils 13, 14 and 15 are attached, whereby for Production of the colored characters, the cover layers 14 and 15 carried out transparently must be provided that the core layer 12 is enriched with the latent pigments.

A possibility can also be seen from FIG. 2, the data carrier body to be provided with labels or stamping foils 16, 17. These stamping foils 16, 17 are in an upstream manufacturing process with latent pigments and then arranged on or in the data carrier.

Of course, it is also the case with a data carrier body manufactured by injection molding of FIG. 2 conceivable, this with lacquer enriched with latent pigments - or Adhesive layers to provide in this way the latent pigments in the disk to bring in, with the help of colored labeling of these becomes.

FIG. 3 shows which change in the absorption behavior in the case of a latent pigment is brought about by irradiation with light of different wavelengths (in this case on the one hand light with laser wavelength ΔE ¹ and on the other hand light in the UV wavelength range ΔE ² ).

If you look at the dotted line of the "active pigment", it is Absorption behavior in the visible spectral range high, d. H. the coloring of the Pigment is clearly visually noticeable.

In contrast, the absorption curve of the "inactive pigment" shown in dashed lines indicates no absorption capacity in the visible spectral range, which means that this pigment is perceived as colorless.

The absorption behavior of the "latent pigment" shown as the third solid curve is influenced by the different wavelengths ΔE ¹ and ΔE ^{2 in} such a way that the absorption behavior is present or not in the visible spectrum and that a subsequent change in the absorption capacity due to renewed irradiation with light of any wavelength is not is possible.

An example of a possible embodiment of the invention is shown below. The chemical compound according to FIG. 4 is suitable as a possible latent pigment. The colored chemical compound shown in FIG. 5 is formed from this compound by laser irradiation. The latent pigment according to FIG. 4 is characterized by a pale yellow color. This latent pigment is cleaved back at a temperature of approx. 260 ° C., and the pigment according to FIG. 5 is formed, which is distinguished by a brilliant red color, Color Index: PR254. In this example, a plastic card with core films 1, 2 made of polycarbonate is used as the data carrier body, which contains a screen printing lacquer based on polyurethane with an admixture of 5% latent pigment content in a coating layer 7. The coating layer 7 of the screen printing lacquer mixed with latent pigments is 10 μm thick. This layer is covered with a transparent cover film 6. The laser beam source, which triggers the conversion of the latent pigment into the red pigment, is a tunable, pulsed OPO laser, which in this example emits radiation with a wavelength of 430 nm. The pulse energy of the laser radiation is 60 mJ and the pulse frequency is 1 kHz. The laser beam passes through a lens system that focuses the beam. The diameter of the laser beam in the focus is 100 µm. The laser system is arranged in such a way that the laser beam penetrates the cover film 6 approximately at a right angle in the focus area and then strikes the lacquer layer mixed with latent pigments. The laser beam is moved at a speed of 10 cm / s at right angles to the coating layer 7 of the data carrier body. The area of the lacquer layer 7 which was exposed to the laser radiation has assumed a clearly visible red color. At this point in time, the unirradiated area still has the pale yellow color of the latent pigment. The surface layer 6 of the data carrier body arranged at the bottom in FIG. 1 is now irradiated with the light of a xenon arc lamp with at least 0.35 W / m ² . The xenon arc lamp emits light with a wavelength of 340 nm. This UV radiation penetrates the transparent cover film 6 and brings about a clear bleaching of the latent pigments in the coating layer 7, which is manifested by the loss of the pale yellow background color of the data carrier body.

LIST OF REFERENCE NUMBERS

1

core film

2

core film

3

cover sheet

4

cover sheet

5

cover sheet

6

cover sheet

7

coating layer

8th

coating layer

9

coating layer

11

core layer

12

core layer

13

topcoat

14

topcoat

15

topcoat

16

label

17

stamping foil

Claims (10)

1. Method for applying coloured marks to a data carrier, preferably made of plastic, by means of a laser system, characterized in that latent pigments which are introduced into at least one surface layer and/or surface-adjacent layer of the data carrier, the absorption characteristics of which pigments are caused to change by energetic excitation, are energetically excited at the areas intended for the marks on the surface of the data carrier by means of laser radiation in the IR and/or visible region in such a way that a colour change occurs in said pigments, and in that, following the colour change of the laser-irradiated latent pigments, the latent pigments not excited by laser radiation are energetically excited by light waves in the UV wavelength region in such a way that the pigments thus irradiated are rendered colourless.
2. Method for applying coloured marks to a data carrier, preferably made of plastic, by means of a laser system, characterized in that in a first method step latent pigments which are introduced into a surface layer of the data carrier, the absorption characteristics of which pigments are caused to change by energetic excitation, are energetically excited at the areas not intended for representing the marks by irradiation with light waves in the UV wavelength region in such a way that the pigments thus irradiated are rendered colourless, and in that in a second method step the latent pigments disposed at the areas intended for representing the marks on the surface layer are energetically excited by means of laser radiation in the IR and/or visible region in such a way that a colour change occurs in said pigments.
3. Data carrier composed of a plastic material with pigments of at least one coloured marking in the form of marks and/or images, characterized in that latent pigments are provided, wherein a change in the absorption characteristics of the pigments is caused by energetic excitation so that in at least one sublayer of the body of the data carrier on the one hand in the case of laser irradiation in the visible and/or IR region a change in colour of the latent pigments irradiated by the laser light occurs, and on the other hand in the case of irradiation with UV light the latent pigments irradiated with UV light are rendered colourless.
4. Data carrier according to claim 3, characterized in that the latent pigments are disposed on a covering film applied to the outer surface of the data carrier.
5. Data carrier according to claim 3, characterized in that the latent pigments are disposed in a core layer which is arranged within the data carrier and is covered by a transparent covering layer to the outside.
6. Data carrier according to claim 3, characterized in that the material of the data carrier is enriched with the latent pigments prior to the forming process for the data carrier:
7. Data carrier according to claim 3, characterized in that the sublayer of the data carrier is a coating applied thereto by means of a pressure technique.
8. Data carrier according to claim 3, characterized in that the sublayer of the data carrier is an adhesion promoter applied thereto by means of a pressure technique.
9. Data carrier according to one of claims 3 to 8, characterized in that the latent pigments belong to the substance group of diketopyrrolopyrroles.
10. Data carrier according to one of claims 3 to 9, characterized in that the UV light source is a UV lamp or a UV laser system.

Images