Identification card readable by a magnetic system

In an identification card to be read by a magnetic system, having two protective plates between which a plate-like data carrier is held and protected, this data carrier being made of a material acting upon a magnetic field and having zones providing the data and acting variously upon the magnetic field, it is proposed, in order to lengthen the life of the card as well as to provide greater security against counterfeiting, that the two protective plates be made from non-magnetizable metal, preferably sheet bronze, and that the data carrier be embedded between the two protective plates in a layer of adhesive, plastic or solder, the two protective plates being thereby firmly joined together.

FIELD OF THE INVENTION 
The invention relates to an identification card which is meant to be read 
using a magnetic system. The card has two protective plates, between which 
a sheet-like data carrier is retained in protected fashion. The data 
carrier is made of a material that acts on a magnetic field, and it has 
zones which provide the data and which act variously upon the magnetic 
field. 
BACKGROUND OF THE INVENTION 
An identification card of this kind, known from German patent disclosure 
document No. DE-OS 28 38 604, has plastic plates acting as the protective 
plates. Plastic plates of this kind undergo severe mechanical wear; their 
behavior at low temperatures is undesirable; they tend to fissure and 
break; and at temperatures beyond 60.degree. C., severe deformation 
occurs. In time, because the plasticizer migrates, these protective plates 
tend to become brittle even under normal conditions. As a result, 
replacement cards are needed relatively frequently. 
OBJECT AND SUMMARY OF THE INVENTION 
To overcome these disadvantages, it is accordingly the object of the 
present invention to provide an identification card of the above general 
type, which is resistent to environmental influences and has a long useful 
life, while reliably protecting the data carrier. 
In order to attain this object, the invention provides that the two 
protective plates be of non-magnetizable metal, preferably sheet bronze, 
and that the data carrier be received between the two protective plates in 
a layer of adhesive, plastic or solder, the two protective plates being 
firmly joined together via this layer. 
Particularly long life and a substantial lessening of the danger of 
buckling are attainable if the layer is of permanently elastic material, 
preferably rubber, a rubber-like plastic, acrylate adhesive, or the like. 
In an identification card in which the zones that provide the data and act 
variously upon the magnetic field are holes, these holes may be filled 
completely with the material making up the layer that firmly joins the 
protective plates to one another. 
In a particularly advantageous feature, a recess can be provided in one of 
the protective plates, into which an optically readable data carrier, 
preferably a photograph, is fitted vertically flush with the protective 
plate and held in place by the adhesive or plastic layer. This provision 
largely protects the optionally readable data carrier from damage and 
wear. 
In order to make counterfeiting as difficult as possible, the adhesive or 
plastic layer can be of a hardenable material that is still free-flowing 
while the card is being made. 
Particularly long life on the part of the identification card is attainable 
if the protective plates are of bronze rolled out until resilient, and 
optionally provided with a surface refinement as well. To save weight, the 
protective plates may be relatively thin, for instance having a thickness 
of only about 0.2 mm. 
The thickness of the layer may amount to approximately 0.4 mm, so that a 
total thickness of only 0.8 mm is required for the card, which is very 
flexible in use and is capable of withstanding severe bending without 
permanent deformation.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
The identification card shown by way of example comprises an upper 
protective plate 1 and a lower protective plate 2, each defining an 
engagement surface between which a data carrier 4 is embedded in a layer 3 
of rubber, of rubber-like material, in particular plastic, or of adhesive 
or solder, which engages the engagement surfaces. In the sectional view of 
FIG. 3, the layer thicknesses are shown with substantial vertical 
exaggeration. The thickness of the protective plates 1 and 2 amounts to 
only approximately 0.2 mm each. The thickness of the layers of adhesive or 
the like between the protective plates 1, 2 and the data carrier 4 is only 
on approximately the same order of magnitude, so that the total thickness 
of the identification card is only about 0.8 to 1 mm. The protective 
plates 1, 2 themselves are preferably of sheet bronze, rolled out until 
resilient, which is relatively resistant to corrosion and may additionally 
be provided with surface refinement, so that even with frequent use only 
limited wearing away takes place. In order to be able to distinguish the 
identification card visually as well, a photograph, company logo or other 
marking of a kind typically found on such a card is fitted as flush as 
possible into a recess 5 in the upper protective plate 1 and is thereby 
protected from damage. 
The data carrier 4--for example a magnetic tape--has parts or zones 6 
differing from the rest of the carrier 4 in acting upon a magnetic field. 
These parts or zones 6 can be created or changed by a magnetic field and 
they form in their totality readable variable data fields. If the parts or 
zones 6 are holes, then in their totality, these holes provide the 
non-variable data of the identification card. The data carrier 4 comprises 
some material acting upon a magnetic field, such as magnetizable metal, so 
that the data can be read using a magnetic system. 
In addition, a further data carrier 7, such as a magnetic tape, can be 
disposed parallel to the data carrier 4; by this means, data that can be 
varied by varying the magnetization can be stored, for instance for the 
purpose of making payments electronically or the like, as is known for 
instance in coinless or card-operated telephones. The further data carrier 
7 can be suitably disposed between the protective plates 1, 2 beside the 
first data carrier 4, so that this data carrier 7 as well is completely 
protected by the protective plates 1, 2. A further possibility is to 
dispose the further data carrier 7 in a recess or hole in one of the 
protective plates 1, 2. Disposing it near the surface facilitates 
magnetization; however, it also increases the danger of damage. 
In the further exemplary embodiment of an idenfitication card shown in FIG. 
4, only one protective plate 2 is provided, which has a groove 8 on one 
side in which a further data carrier 7 is firmly retained approximately 
flush with the surface by a layer 3.