EP0308904A2 - Multi-layered printable identity card and method for its manufacture - Google Patents

Abstract

An identification card is provided with a character set that can be used as a printing block, the "natural foamability" of the plastic materials generally used for identification cards such as PVC and polycarbonate, which can be caused by laser action, being used in order to achieve a relief height sufficient for a clear imprint of the characters. The standard-compliant total height of the embossed characters in relation to the rest of the card surface is achieved by an additional deformation of the card body in the embossed character area with the formation of flat plateaus.

Description

The invention relates to a multilayer identification card with at least one card surface made of plastic, which in some areas has characters or symbols in a relief structure that can be used as a printing block, and to a method for producing such identification cards.

ID cards in the form of credit cards, bank cards, cash payment cards, authorization cards or the like are used in a wide variety of areas, such as. B. include cashless payments, access control systems and a wide variety of service systems. These ID cards generally have data related to the cardholder, which are applied in the so-called personalization process. A common form of the possible representation of these characters is the embossing, in which the user-related data are embossed in relief from the back of the ID card to the front of the card. To make the individual characters more visible, they are additionally colored in their apex areas.

However, this cost-effective form of personalization has the disadvantage that the user-related data are exposed to attempts at forgery relatively unprotected. Since the card materials are usually thermoplastics, in particular PVC, the embossed data can be ironed back or embossed relatively easily with such manipulations and the cards can be re-embossed with other data. The original coloring can be easily removed with commercially available solvents and a fake card with a changed data set can be recolored. It also shows that this coloring is rubbed off over time in daily use. This not only makes counterfeiting easier, it also often severely limits the legibility of the data.

Despite these considerable disadvantages, this form of personalization is used more widely, particularly in the case of credit cards, since the character set which can be used as a printing block allows the data to be transferred easily from the card to the current payment slip. So-called imprinters are used, in which the card and the payment slip are inserted. The user data is transferred to the payment document via a mechanical embossing process using carbon or carbon paper (DE-PS 20 18 927). An internationally defined standard determines, among other things, the location of the embossed data on the ID card, its shape and its relief height (ISO standards 7811/1 and 7811/3).

In particular because of the high risk of forgery of this embossed data, suggestions have already been made as to how the additional characters can be protected against changes by additional measures (DE-PS 32 48 784, DE-PS 33 14 327).

Other developments have attempted to use other process techniques to produce characters that can also be used as printing blocks, but cannot be counterfeited in their simple form.

For example, from DE-OS 22 23 290 a method is known in which the embossed data appear only on a card surface. In this process, the personalization data are embossed in metal plates and transferred to the card surface when the ID card is laminated. During the lamination process, the card material softens and flows into the depressions in the metal plate without leaving a negative relief on the back. This creates an embossing in which the characters can no longer be embossed.

However, this method is much more complex than the usual embossing method, since a metal plate with the correspondingly engraved personalization data must be produced for each card and this personalization process is a process step that cannot be separated from the card production.

Only through DE-OS 32 13 315 was an identification card and a method for producing the same presented, with which identification cards can not only be provided in a simple form with characters that can be used as a printing block, but in which these characters are also available in a particularly forgery-proof form . The method presented there proposes to provide the identification card with a foamable, corresponding propellant-containing plastic layer. This layer is then specifically foamed locally to form the desired characters in a relief structure. A laser beam is preferably used for this purpose, which generates the heat necessary for triggering the foaming process or activating the blowing agents in this foamable plastic material. By appropriate selection of the plastic material, the blowing agent and the laser parameters such as intensity, etc., this foaming process can be carried out in a targeted manner in order to produce the characters in accordance with the standards with regard to their dimensions and their relief height. At the same time, this foaming can be associated with discoloration of the plastic material, so that the previously necessary coloring process is unnecessary. Since the discoloration takes place in the plastic material itself and is also irreversible, it is forgery-proof and resistant to abrasion.

In order to achieve the relief height of 0.48 or 0.46 mm above the card surface required by the standard (ISO standard 7811/1), the use of special plastic foils, which are mixed with the appropriate blowing agents, is necessary agile. Although suitable plastics and blowing agents are known for this purpose, the necessity of installing such plastic layers can, in some cases, lead to certain card structures, which are required for other reasons, not being feasible, or e.g. B. the desired transparency is not achieved due to the inherent color of the blowing agents.

The invention is therefore based on the object, while maintaining the simple, but particularly forgery-proof, individual labeling option given by the laser method, to provide an identification card which can be equipped with a standard embossed character set even without the use of special foamable foils.

This object is achieved by the features specified in patent claim 1.

The invention is based on the idea of using the "natural foamability" of plastic materials generally used in identity cards, such as PVC and polycarbonate, which can be caused by laser action, in order to achieve a relief height sufficient for a clear imprint of the characters and the total height of the embossing characters required according to the standard to be realized above the rest of the card surface by an additional deformation of the card body in the area of the embossed character.

As is known from DE-PS 31 51 407, gas bubbles and fine black dots occur in the action of a laser beam with a corresponding intensity in a plastic material that is sensitive or sensitized to the laser beam, which not only discolor the material, but also increase the volume of the plastic material result (this side effect was not taken into account in the mentioned publication).

In the present invention, this increase in volume caused by the gas bubbles is now used in a targeted manner to generate characters which are not only apparent in color but also in their relief height in relation to the surroundings. As experiments have shown, plastic material, such as. B. PVC, can be enlarged by the action of a laser beam even without additional propellant by 30% and more of its volume, without the film losing significant strength in these areas.

Appropriate optimization of the material and process parameters (plastic material, layer structure, layer thickness, laser intensity, beam guidance, etc.) can therefore be used to generate characters in a relief height sufficient for an impression, the surface in the character area being influenced only imperceptibly and, in particular, still being completely self-contained is. The last-mentioned characteristic is of particular importance for the quality of the later reprint of the data. Only at very high intensities does the formation of the gas bubbles lead to bursting in the cover film, as is known from the aforementioned DE-PS.

It should be noted here that - in order to achieve a good impression of the relief signs - the effective maximum height of the sign in relation to its immediate surroundings does not necessarily have to be the 0.46 mm specified by the standard. In principle, a relief height of approximately 100 Ì is already sufficient for a mechanical impression of relief signs. This relief height is now achieved according to the invention with the abovementioned laser inscription, preferably by means of a corresponding increase in volume in the transparent cover film of the identification card, while the relief height (360 über) above the card surface required to meet the standard is generated by deforming the card to form plateaus becomes.

A double-layer transparent cover film is preferably used for the identification card according to the invention, a plastic material being used for the outer layer, which is somewhat less sensitive to the laser effect. This ensures that the outer film softens, but the formation of bubbles is somewhat less than in the more sensitive inner film. The outer film can then evade the inner pressure resulting from the formation of bubbles, itself also contributes to the increase in volume, but is subjected to a somewhat less thermal load in view of a good surface quality.

The plateaus on which these characters are formed by means of laser can certainly cover a larger area, e.g. B. the area of one or more lines of characters or they can also be composed of a plurality of smaller plateaus, each of which can only accommodate one character.

Various methods are available for plateau formation, e.g. B. a mechanical embossing, thermal embossing or embossing the card material while softening the material by means of a high-frequency alternating electromagnetic field. The latter method has the advantage that, by appropriately designing the electrodes which simultaneously form the embossing stamp, the card only has to be thermally stressed in the areas which are actually to be deformed. As will be shown later, this fact can also be used to be able to carry out the plateau formation after the laser marking.

An important advantage of the present invention is that the usual materials known from card production can be used for the construction of the card, only the layer thicknesses required to achieve a sufficient relief height being observed.

Furthermore, the signs of the plastic material introduced in this way are extremely tamper-proof, since both the increase in volume and the simultaneous discoloration (blackening), which can extend into the opaque card core, are irreversible changes in the plastic material. Such characters once generated are neither chemically nor mechanically reproducible.

The card manufacturing and personalization processes are also two completely independent process stages. Personalization can thus represent the last step in the production of ID cards. The main advantages of this circumstance include: B. that in the card manufacturing "scrap cards" can be discarded before the personalization process or already personalized cards are no longer endangered by subsequent manufacturing steps.

The relief structures achieved by the natural "foamability" of the plastic material also have sufficient strength, which is necessary for the frequent later use in the above-mentioned imprinters for printing the user-related data.

The proposed card structure with the transparent double-layer cover film also allows other authenticity features, such as. B. the "laser tilt image" known from DE-OS 36 34 865 or the "parallax image" known from DE-OS 36 34 857 by laser.

In addition to the font with the relief structure, a font without a relief structure can also be generated, the intensity and the scanning speed of the laser beam having to be controlled accordingly in a manner to be explained later. This means that the ID card can also be labeled. B. possible in the area in which the magnetic strip is normally arranged on the back. A font with a relief structure would have a negative impact on the readability of the magnetic data, since transport rollers arranged in this area impair the smooth card transport.

• Fig. 1 eine nach einem bekannten Verfahren mit Prägezeichen versehene Ausweiskarte in der Aufsicht,
• Fig. 2 dieselbe Karte in einer Schnittansicht,
• Fig. 3 eine erfindungsgemäße Ausweiskarte vor der Personalisierung,
• Fig. 4 dieselbe Karte in einer Schnittansicht,
• Fig. 5 eine erfindungsgemäße Ausweiskarte nach der Personalisierung,
• Fig. 6 dieselbe Karte in einer Schnittansicht,
• Fig. 7, 9, 10 weitere Ausführungsformen,
• Fig. 8 einen Ausschnitt aus der Prägevorrich­ tung.

Further advantages and developments of the invention can be found in the subclaims and the following exemplary embodiments, which are explained in more detail with reference to the drawings. Show it:

• 1 is a top view of an identification card provided with embossed characters according to a known method,
• 2 the same card in a sectional view,
• 3 shows an identification card according to the invention prior to personalization,
• 4 the same card in a sectional view,
• 5 shows an identification card according to the invention after personalization,
• 6 the same card in a sectional view,
• 7, 9, 10 further embodiments,
• Fig. 8 shows a detail from the embossing device tung.

1 and 2 show an identity card 1, such as. B. a credit card with the information content typical for them. This is e.g. B. the specification of the issuing credit institution 2, the z. B. be applied by printing to the card ticker. Furthermore, the card has an authenticity feature 3, such as. B. a hologram embedded or glued into the cover film. The areas 4a and 4b of the card are reserved according to the international standard for the embossed characters 5, which are usually introduced in the area 4b in three or four lines (for the sake of simplicity, only one line is shown in the drawing). These characters are created after the card has been made. H. after welding the individual card layers, stamped in a corresponding embossing press. For better visual visibility, the characters are then displayed in their raised areas, i.e. in the crown areas 6, colored.

2 shows the map in a sectional view with a two-layer structure shown here by way of example. An opaque card core 7 carries z. B. one or both sides of a printed image 8 and in the back of a magnetic strip 9 is embedded. Among other things, an electrical circuit (not shown in the figure) can be embedded in a cutout in the card core. The embossed characters 5 were introduced by pressing them in from the back and correspondingly deforming the card body, the card being deformed to such an extent that the apex regions 6 reach a height H of approximately 0.45 mm above the card surface.

As already mentioned in the introduction, these known cards have the disadvantage that the embossing is reversed by correspondingly embossing the characters and then the same card again with changed data can be newly shaped. The counterfeiter also has no problem removing and reapplying the coloring because the discoloration can be removed with simple solvents.

3 now shows the semi-finished product 20 of a card according to the invention before the personalization process. In a preferred embodiment, the identification card is also embossed, but in this embossing it is not the characters themselves that are introduced, but rather only partial areas 21a, b, into which the embossed characters are to be introduced, raised by a uniform 1/4 0.35 mm above the card surface. 3 in FIG. Areas marked 21a and 21b are hereinafter referred to as plateaus. You can e.g. B. have the size of a line or a multi-line field. These plateaus now serve to achieve the effective relief height of the embossed characters of 0.46 mm as required by the standard.

Fig. 4 shows the semi-finished product 20 of the identity card in the sectional view. In the preferred exemplary embodiment shown, the card according to the invention has a three-layer structure. These three layers 22-24 are the opaque core layer 22 and a two-layer transparent cover layer 23, 24. The core layer can, as already mentioned above, be provided on one or both sides with printed images 25, 26 and also carry other security features, such as, for. B. a security thread, watermark-like effects or other features that serve to protect against forgery of the card structure. This opaque core layer 22 is covered on one side by a one-layer, but preferably two-layer transparent cover film which is matched to the laser inscription in terms of the choice of material. The two-layer cover film consists of two transparent PVC layers 23, 24, which have an improved absorption compared to the laser beam to have ability. Such films are such. B. from the previously mentioned documents DE-PS 31 51 407 and DE-OS 36 34 857 known. For the inner cover film 23, a film is selected which is more sensitive to the laser beam than the outer cover film 24. With this structure, the requirements for a maximum volume increase while maintaining the surface quality of the card can be met in a satisfactory manner. This card can be completely finished, ie printed, laminated and embossed, so that the necessary data only have to be added as a last step in the context of personalization. Of course, the back of the card can also be covered with a transparent cover film, equipped with a magnetic strip and / or an integrated circuit.

In a personalization station, the data which can be introduced by means of a laser are introduced into the card, the embossing marks 28 being recorded in the plateau region 21 (FIGS. 5, 6). For this purpose, the laser beam 29 is guided correspondingly over these plateaus 21a, b of the card 19 to form the characters, the recording parameters such as intensity, scanning speed, pulse frequency etc. being selected such that the greatest possible formation of bubbles 30 results with simultaneous softening of the film, without causing sharp bursts and pronounced crater formation in the surface area. In order to determine the intensity required for this, a so-called gray wedge can be recorded in a trial run, on the basis of which the optimal laser parameters can then be determined empirically.

A layer thickness of 100 to 150 150 is preferably selected for the inner cover film 23 and a thickness of 150 to 200 Ì for the outer cover film 24. This in total Together with 250 to 350 Ì thick transparent cover film can be expanded to a thickness of 350 or 450 Ì by appropriate laser exposure. Because of the local limitation of the "foaming" area, an increase in volume of approximately 30% is reflected directly in a corresponding change in thickness. This expansion (a) of approx. 100 Ì achieved by the laser effect together with the plateau formation (¼ 0.36 mm) created by the mechanical embossing results in the height H of 0.46 mm above the remaining card surface required for the standard. Attempts to use this card as a printing block in common imprinter devices showed excellent print quality.

The relief formation can be additionally optimized by means of an appropriate laser beam guidance. For this purpose, the laser operated in pulse mode is guided over the card surface in such a way that the successive pulses overlap locally. The effect of the laser beam on the material is thus increased with the intensity remaining the same, since the following pulse strikes partially blackened and thus more absorbent material.

The same card structure also allows the identification card to be labeled without simultaneously creating a relief. It is important to ensure that the intensity of the laser beam is reduced in such a way that the recording is preferably carried out without overlapping the individual laser pulses, that - as is known from DE-OS 36 34 857 - only a blackening in the more sensitive inner cover layer and essentially there are no visible bubbles. This labeling method is particularly suitable for labeling the area of the card in which the magnetic stripe is located on the back, since here a surface that is smooth on both sides is necessary for scanning the magnetic stripe. Usually concerns this is the information provided by the institute 31.

The data is preferably recorded by scanning the card surface in accordance with a dot or line matrix, in which the laser beam is guided line by line over the card and the character is generated by correspondingly fading the laser beam on and off at the corresponding matrix points. Depending on the font - with or without relief - the laser beam intensity and / or the pulse overlap is selected.

The card 19 shown in FIG. 5 also has a visually verifiable authenticity feature 27, which is also generated with a laser and whose appearance can change depending on the viewing angle. Such authenticity features are known from the documents, DE-PS 36 34 865 and DE-OS 36 34 857, the disclosure of which reference is made here. It is precisely here that the versatility of laser marking can be seen, which allows data with both the same relief and relief and corresponding visual authenticity features to be created with the same card structure by simply changing the laser control or intensity, possibly combined with a partial embossing (plateau, lens grid) Insert card.

Fig. 7 shows a further embodiment, in which the plateau 21 each has only the size of a character 28 and a plurality of plateaus placed next to each other are embossed on the card. If technically justifiable, the number of individual fields can also be adapted to the respective number of characters required for the card-specific lettering.

The individual plateaus or the large-area plateaus shown in the aforementioned examples can be achieved in a variety of ways. An embossing method is preferred in which the plastic material of the card 41 (FIG. 8) is softened by the action of a high-frequency electrical field and is deformed by appropriate embossing molds. The embossing molds can be electrodes 40a, b for the alternating electrical field. The processing of PVC with the help of high-frequency alternating electrical fields is e.g. B. known from the general literature.

This deformation technique has the advantage that the card is only thermally stressed in the areas to be effectively deformed. Furthermore, this deformation is difficult to recover, since, in contrast to the mechanical cold deformation, this is a deformation "without memory". The HF deformation also allows the plateaus to be formed even after the laser marking has been formed. For this purpose, the embossing stamp 40a has a cutout 42 in the card area which carries the already lasered relief data 43, so that the mechanical effect of the embossing stamps is concentrated only on the edge regions of the plateau to be formed. The lasered relief data therefore remain undamaged during the embossing process and this allows the embossing to be carried out even after the laser inscription. This solution thus has the further advantage that in the case of laser marking, in which the cards are automatically separated, transported and stacked, it is possible to work with flat cards.

Nevertheless, other embossing processes can be used for the formation of the plateaus, if so desired, e.g. B. the known cold forming or thermal deformation. Furthermore, it is also possible to directly cover the card to cause an increase in the card surface in the embossed data area. For this purpose, matrices with the corresponding negative relief can be inserted between the card and the laminating plate. Since the matrix here, in contrast to the teaching of DE-OS 22 23 290, is the same for all cards, this does not constitute an overly complex intervention in the common card production technology. The formation of plateaus in the laminating process has the advantage, among other things, that the rear surface of the card remains flat in the entire area and the print on the back is not disturbed by the embossing, as is the case with the known cards.

The embossing dies used in the above-mentioned deformation techniques can additionally have a relief in their surface, whereby an embossing pattern (32, FIG. 5) is embossed into the card surface at the same time as the plateau is formed. This embossing pattern can e.g. B. represent a micro relief, texturing, a sequence of characters, logos or similar symbols. The map thus contains a further feature that makes replication or change considerably more difficult, especially if a self-contained pattern runs over the entire plateau area and is only interrupted by the lasered relief symbols.

In a further embodiment (FIG. 9), the multilayer card body 50 is provided with an additional film piece 51 in order to form the plateaus in the embossed area. This embedded between core and cover sheet 53 or 54 piece of film 51 can, for. B. be a film of the same transparent material as the inner cover film layer of the embodiment shown in Fig. 4 or 6. This increases the thickness of the map by about 0.3 to 0.4 mm in the required range. The characters with the relief structure are then formed by means of, as already described above a laser beam, the volume being increased by the formation of bubbles combined with a simultaneous discoloration in these transparent layers.

This additional piece of film 51 can, however, also be glued to the outer surface of the finished card or welded onto the card. In this case, the two-layer cover film structure shown in FIG. 4 is recommended as the material for this additional film. In order to prevent a later exchange of this piece of film, the intensity of the laser beam can be controlled in such a way that the card core is at least blackened in its surface and the user data can also be recognized on the card core layer.

The plateau formation by means of an additional piece of film has the advantage that the back of the card remains completely flat and thus a printed image on the back of the card is not disturbed by impressions. In addition, the plateaus gain stability due to this flat back of the card.

Especially in the case of larger plateaus in terms of area, which are created according to one of the aforementioned methods with simultaneous formation of a negative relief on the back of the card, it can happen that the plateaus are pushed through over time by the mechanical loads in the imprinter devices. In the middle area of the plateaus in particular, the embossed data then no longer have the height required for producing a legible print.

In order to counter this wear and tear, the support surface for the card in the imprinter devices could be provided with support elements which engage in the cavities on the back of the card and the plateaus during printing support the process. Preferably, however, the embossing dies or laminating plates in the plateau area on the back of the card are additionally provided with depressions in the form of bores, channels, etc., into which the softened card material can flow during the formation of the plateau.

The structures formed by these depressions in the form of knobs, support rails and other profiles then serve to support and / or stiffen the plateau-like elevations on the rear. 10 schematically shows such a card 60 with a plateau-like elevation 61 on the front of the card, which is supported on the back by a support profile 62 in the form of support rails 63 which run through the negative structure.

This effectively prevents the embossing data from being pushed through while the card is being used.

Claims (16)

1. ID card with at least one card surface made of plastic, which has a portion of characters or symbols in a relief structure that can be used as a printing block, characterized in that
- This relief structure is formed in two stages, whereby
- The first stage is a plateau-like elevation (21a, b) of the card surface in the area of the characters to be introduced (5) and
- The second stage is an increase in volume (30) of the plastic material caused by the local action of a laser beam (29), which increases in the area of these plateau-like elevations (21a, b) in the form of a available characters or symbols. 2. ID card according to claim 1, characterized in that the card consists of at least one opaque card core (22) and a transparent in the visual spectral range, but changeable by the laser radiation cover film. 3. The identity card of claim 2, gekennkennzeichnet characterized in that the cover film has two layers and the plastic material of the outer cover film layer (24) has a lower as compared to the inner cover film layer (23) Absorption capacity with respect to the laser beam. 4. ID card according to one or more of the preceding claims, characterized in that the plateau-like elevations (21a, 21b) comprise larger areas for receiving several embossed characters (5) and the correspondingly recessed areas on the back of the card with a support and / or stiffening profile ( 62) are provided. 5. ID card according to one or more of the preceding claims, characterized in that the sum of the height of the plateau-like elevations (21a, 21b) and the increase in thickness caused by the laser beam (a) in the cover film is approximately 0.46 mm. 6. ID card according to one or more of the preceding claims, characterized in that the card (19) outside the plateaus (21a, 21b) is provided with a laser inscription (31) without simultaneous relief formation. 7. ID card according to one or more of the preceding claims, characterized in that the identification card (19) carries further visual identification features (27) introduced with the aid of a laser beam in other forms of representation. 8. ID card according to one or more of the preceding claims, characterized in that the card surface carries a mechanically embossed microrelief (32) at least in the region of the plateaus (21a, 21b). 9. A method for producing an identification card with at least one card surface made of plastic, which has characters or symbols in a partial area in a relief structure that can be used as a printing block, characterized in that
- The characters, symbols, etc., which can be used as a printing block, are formed in two mutually independent process steps, wherein
- In one process step, the card body is deformed in the areas in which the characters are to be introduced to form flat plateaus rising above the rest of the card surface, or its thickness is increased by applying additional layers, and
- In another method step in the area of this plateau, at least one plastic layer of the card body is formed to increase the volume of the relief structure corresponding to the characters, symbols, etc. locally under the action of a laser beam. 10. A method for producing an identification card according to claim 9, characterized in that to form the plateaus the identification card material in an embossing station is at least locally softened and mechanically deformed by the action of a high-frequency alternating electrical field. 11. The method according to claim 10, characterized in that the electrodes used to generate the alternating electrical field simultaneously form the embossing dies for forming the plateaus. 12. The method according to claim 11, characterized in that at least one of the electrodes is preheated. 13. The method according to claim 11, characterized in that the electrodes have recesses in order to keep certain areas of the card away from mechanical loads during the generation of the plateaus. 14. The method according to one or more of the preceding claims, characterized in that the laser used to generate the volume increase is operated in pulse mode, the pulse frequency and the recording speed being selected so that temporally successive pulses at least partially overlap locally on the card surface. 15. The method according to claim 14, characterized in that laser inscription is carried out outside the plateau region without simultaneous formation of a relief structure, the laser beam being guided in a non-overlapping form and correspondingly low intensity over the identity card surface. 16. The method according to claim 14 or 15, characterized in that the recording is carried out by point or line scanning of the card.

Images