DE10011486A1 - Card-type data carrier e.g. passport or credit card, has information applied by local surface treatment by laser radiation so as to reveal underlying layer of different color - Google Patents

Abstract

Card-type data carriers requiring engraving of one surface of the plastics material by a laser process in order to remove local material so as to make visible the underlying layer of a different color, often result in damage to the surface of the data carrier by the removal of material. To provide safe processing of the data carrier surface, selective reduction by laser beam of the absorptive capacity of at least one layer of the data carrier, and for at least one wavelength, can now be carried out so as to change the absorption-and reflection-properties without damaging the surface of the data carrier.

Description

The invention relates to a card-shaped data carrier and to a method its manufacture.

Card-shaped data carriers of this type are identity cards, bank cards, credit cards or the like. made of plastic.

DE 29 07 004 C2 discloses visually readable information on identity cards to apply by means of laser radiation. The information is charred and / or carbonization of the plastic material visible, the information itself black or gray against a different colored background (e.g. opaque or transparent). Other colors cannot be created with it. The laser marking is opposite other labeling methods more secure against counterfeiting or manipulation.

In addition, it is also known that laser radiation can be used to engrave in particular, it is possible to localize individual layers of a multilayer card body to ablate. According to DE 30 48 733 C2, this fact is used to differentiate apply colored information on identity cards. It becomes a multi-layered one Card body used, the layers of which are different colors. Through the local Removal of individual layers by laser radiation, the underlying color changes Layer visible. This has the procedure for labeling card-shaped data carriers however, the disadvantage that the surface of the data carrier is damaged by the removal becomes.

The object of the invention is a card-shaped data carrier and a method for Manufacture of the same to create the application of colored information by means of enables safe laser processing without damaging the surface of the data carrier.

This object is achieved through the characterizing features of the independent claims solved. The invention is based on the idea of absorbing at least one layer of the data carrier for at least one wavelength  (Wavelength range) to be selectively reduced locally by laser radiation. With that change the absorption and reflection properties of the layer locally and thus the color impression at this point.

Fig. 1 shows a section of a card-shaped data carrier that has three layers ( 1 , 2 , 3 ), each of which has different absorption spectra before the laser irradiation. These three layers ( 12 , 3 ) are preferably located on a white substrate layer ( 4 ). Above the three layers ( 1 , 2 , 3 ) whose absorption is to be changed under the influence of laser radiation, there is also a cover layer ( 5 ) which is transparent in the visible wavelength range and in the range of the laser radiation used.

In FIG. 2, the absorption spectra of the layers (1, 2, 3) shown before laser irradiation.

The absorption behavior before laser radiation or the reflection behavior after Laser marking of the individual layers is made using appropriate coloring pigments causes which are added to the layers as additives. Ideally, one layer locally completely bleached by the laser radiation, so that the layer on its own locally (in the laser writing spot) is at least almost transparent.

In the exemplary embodiment shown, the first laser-sensitive layer ( 1 ) has an absorption maximum in the green spectral range. Before laser irradiation, this layer ( 1 ) is magenta in color. The second laser-sensitive layer ( 2 ) has an absorption maximum in the red spectral range. This layer ( 2 ) is cyan before laser irradiation. The third laser-sensitive layer ( 1 ) has an absorption maximum in the blue spectral range. This layer ( 1 ) is yellow before laser irradiation.

When irradiated with a green laser beam of sufficient intensity, the first laser-sensitive layer ( 1 ) loses its absorption capacity locally where it was exposed to the green laser radiation, so that this layer ( 1 ) is transparent at this point. When viewing this area with white sunlight, this point (stain) appears green, the coloring being caused by the subtractive color mixture. The incident light beam (white light, e.g. sunlight) passes through the first layer ( 1 ) which is transparent after the laser beam has been applied. When passing through the second layer ( 2 ), the red portion is filtered out of the white light beam by absorption. When passing through the third layer ( 3 ), the blue part is filtered out of the light beam, so that only the green part remains of the original white light beam. Finally, the green light beam is reflected on the white substrate layer ( 4 ). This point appears green to the viewer.

When irradiated with a red laser beam of sufficient intensity, the second laser-sensitive layer ( 1 ) locally loses its absorption capacity where it was exposed to the red laser radiation, so that this layer ( 2 ) is transparent at this point. When you look at this spot with white sunlight, this point (spot) appears red, whereby the coloring is caused by the subtractive color mixture. When passing through the first layer ( 1 ), the green portion is filtered out of the white light beam. The second layer ( 2 ), which is transparent at this point after the laser beam is applied, passes through the light beam without absorption. When passing through the third layer ( 3 ), the blue portion is filtered out of the light beam, so that only the red portion of the original white light beam remains. Finally, the red light beam is reflected on the white substrate layer ( 4 ). This point appears red to the viewer.

When irradiated with a blue laser beam of sufficient intensity, the third laser-sensitive layer ( 3 ) loses its absorption capacity locally where it was exposed to the blue laser radiation, so that this layer ( 3 ) is transparent at this point. When you look at this spot with white sunlight, this point (stain) appears blue, the coloring being caused by the subtractive color mixture. When passing through the first layer ( 1 ), the green portion is filtered out of the white light beam. When passing through the second layer ( 2 ), the red portion is filtered out by absorption. The third layer ( 3 ), which is transparent at this point after the laser beam has been applied, then passes through the light beam without absorption, so that only the blue portion of the original white light beam remains. Finally, the blue light beam is reflected on the white substrate layer ( 4 ). This point appears blue to the viewer.

In this way, an originally black, gray or dark brown stain can be set red, blue or green - depending on which of the laser-sensitive layers ( 1 , 2 , 3 ) in the sandwich structure you bleach.

In Fig. 3 the triple color that can be created in this way is shown. Of course, the laser beam can also be applied so that the color dots lie one above the other.

In one embodiment, the laser-sensitive layers ( 1 , 2 , 3 ) are plastic films which are connected to one another by lamination. At least one laser-sensitive layer ( 1 , 2 , 3 ) can also be an adhesive layer between plastic films within the sandwich structure.

In an alternative embodiment, the laser-sensitive layers ( 1 , 2 , 3 ) are applied layer by layer to the white substrate layer ( 4 ) in a coating process - for example as a lacquer.

The layer structure has a layer in which all bleachable color pigments (magenta, cyan and yellow) are included, a great advantage. The color pigments differ not only in their absorption maximum, where they are bleached, but otherwise also with regard to their chemical and physical Properties, in particular not every pigment can be found in every plastic film or varnish bring in. In addition, the pigments can also influence each other. Chooses however, if you have a separate layer for each pigment, you can use the plastic film or varnish specially tailored to this pigment.

Of course, the invention is not limited to three laser-sensitive layers. Rather, two or four laser-sensitive layers can also be present.

Claims (12)

1. Card-shaped data carrier, consisting of at least one layer ( 1 , 2 , 3 ), into which visually readable information in the form of a change in the optical property due to an irreversible change in material caused by a laser beam is introduced, characterized in that the absorption capacity of this layer ( 1 , 2 , 3 ) for at least one wavelength (λ ± Δλ) due to the laser radiation is at least partially reduced. 2. Card-shaped data carrier according to claim 1, characterized in that the layer ( 1 , 2 , 3 ) has color pigments, which under the influence of laser radiation with the wavelength (λ ± Δλ) their absorption capacity for the wavelength (λ ± Δλ) at least partially to lose. 3. Card-shaped data carrier according to claim 1 or 2, characterized in that

• it has two or more layers ( 1 , 2 , 3 ), each of which has a different absorption capacity for at least one wavelength (λ ± Δλ),
• - The absorption capacity of at least one layer ( 1 , 2 , 3 ) for at least one wavelength (λ ± Δλ) is at least partially reduced due to the laser radiation.

4. Card-shaped data carrier according to one of the preceding claims, characterized in that

• - It has at least two layers ( 1 , 2 , 3 ), each of which has a different absorption capacity for at least two different wavelengths (λ ₁ ± Δλ ₁ , λ ₂ ± Δλ ₂ , λ ₃ ± Δλ ₃ ), wherein
• - the absorbance of a first layer (1) for the wavelength (λ ± Δλ _{1 1)} under the influence of laser radiation of the wavelength (λ ₁ ± Δλ ₁₎ is at least partially reduced,
• - the absorbance of a second layer (2) for the wavelength (λ ₂ ± Δλ ₂₎ under the influence of laser radiation of the wavelength (λ ₂ ± Δλ ₂₎ is at least partially reduced.

5. Card-shaped data carrier according to one of the preceding claims, characterized in that at least one of the layers ( 1 , 2 , 3 ) is at least partially transparent to visible light (400 nm to 800 nm). 6. Card-shaped data carrier according to one of the preceding claims, characterized in that the layers ( 1 , 2 , 3 ), the absorption capacity of which is reduced under the influence of the laser radiation, are arranged on a white substrate layer ( 4 ). 7. Card-shaped data carrier according to one of the preceding claims, characterized in that above the layers ( 1 , 2 , 3 ), the absorption capacity of which is reduced under the influence of the laser radiation, a cover layer ( 5 ) which is transparent to visible light is arranged. 8. Card-shaped data carrier according to one of claims 2 to 7, characterized in that the layers ( 1 , 2 , 3 ) are laminated plastic films, in which the color pigments are contained. 9. Card-shaped data carrier according to one of claims 2 to 7, characterized in that the layers ( 1 , 2 , 3 ) are superimposed lacquer layers in which the color pigments are contained. 10. A method for applying information to card-shaped data carriers, the card-shaped data carrier having at least one layer ( 1 , 2 , 3 ) into which visually readable information is introduced in the form of a change in the optical property due to a material change irreversibly caused by a laser beam, marked by

• the provision of a card-shaped data carrier which has at least one layer ( 1 , 2 , 3 ), the absorption capacity of which is at least partially reduced for at least one wavelength (λ ± Δλ) as a result of the laser radiation,
• - Acting on this layer ( 1 , 2 , 3 ) of the card-shaped data carrier with the laser radiation in order to reduce the absorption capacity of this layer for the wavelength (λ ± Δλ).

11. The method according to claim 10, characterized by

• - The provision of a card-shaped data carrier which has two or more layers ( 1 , 2 , 3 ), each of which has a different absorption capacity for at least one wavelength (λ ± Δλ), and the absorption capacity of at least one layer ( 1 , 2 , 3 ) is at least partially reduced for at least one wavelength (λ ± Δλ) as a result of the laser radiation,
• - Application of this one layer ( 1 , 2 , 3 ) of the card-shaped data carrier with the laser radiation in order to reduce the absorption capacity of this layer for the wavelength (λ ± Δλ).

12. The method according to any one of claims 10 or 11, characterized by

• the provision of a card-shaped data carrier which has at least two layers ( 1 , 2 , 3 ) which each have different absorption capacities for at least two different wavelengths (λ ₁ ± Δλ ₁ , λ ₂ ± Δλ ₂ , λ ₃ ± Δλ ₃ ), in which
  • 1, the absorption capacity of the first layer (1) for the wavelength (λ ± Δλ _{1 1)} under the influence of laser radiation of the wavelength (λ ₁ ± Δλ ₁₎ is at least partially reduced,
  • 2. the absorptivity of the second layer (2) for the wavelength (λ ₂ ± Δλ ₂₎ (λ ₂ ± Δλ ₂₎ at least partially reduced under the influence of laser radiation of wavelength,
• - the application of the first layer ( 1 ) of the card body with laser radiation of the wavelength (λ ₁ ± Δλ ₁ ) in order to reduce the absorption capacity of this layer for the wavelength (λ ₁ ± Δλ ₁ ),
• - The application of the second layer ( 1 ) of the card body with laser radiation of the wavelength (λ ₂ ± Δλ ₂ ) in order to reduce the absorption capacity of this layer for the wavelength (λ ₂ ± Δλ ₂ ).