Abstract:
To determine the position of a chip card ( 14 ) in the card cage of a card reader the invention provides for the presence of the chip contact surface ( 18 ) to be detected in the four possible positions in which the chip ( 16 ) of the card ( 14 ) inserted into the card reader can be situated. To this end a sensor ( 20 ) for detecting the chip card surface ( 18 ) and linked to an evaluation unit ( 28 ) is arranged opposite each of the possible positions.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is related to International Application No. PCT/EPOO/01803 filed Feb. 10, 2000 and German patent application No. DE 199 08 161.1 filed Feb. 25, 1999, both of which are entitled “METHOD AND DEVICE FOR DETERMINING THE POSITION OF A CHIP CARD IN A CARD READER”. Applicant claims priority of both of the above-identified applications. 
    
    
     FIELD OF THE INVENTION 
     The invention concerns a method for determining the position of a chip card in a card reading device, in cases where the chip is arranged eccentrically in the card, as well as a device for carrying out such a method. 
     BACKGROUND OF THE INVENTION 
     If a chip card of a type conventional today, which has no magnetic readable strip or whose magnetic readable strip is not written on, is inserted into a card reader with a chip card contact station, the chip card can take four different orientations relative to the chip contact station. Nevertheless, only one orientation leads to a successful contacting of the chip, since the chip card contact station can only make contact with one area of the chip card. Since the user generally cannot determine where the contact elements of the reader are located, he often must make several insertion attempts, until he finds out in which orientation he has to insert the chip card into the card reader to assure a successful contacting. 
     In the case of cards with a magnet strip it is already known to provide means for predetermining the magnetic track. Thereby insertion of non-standard objects and especially a manipulation of the reading device is inhibited. With this magnet track pre-recognition, it can further be determined among other things that the actual insertion orientation of the card is not correct. It cannot however be determined in which orientation the card is actually located and how the user must change the orientation of the card in order to make possible a chip card contacting. 
     SUMMARY OF THE INVENTION 
     The invention has as its basic object the provision of a method of the aforementioned kind in which the actual orientation of a card can be determined and as the case may be, it can decided in which way the orientation of the card has to be changed in order to correctly insert it into the card reader. 
     The above object is solved in accordance with the invention in that at the four possible positions which a chip of a chip card inserted into the card reading device can take, the presence of the chip contact surface is determined. 
     With the method of the invention it is therefore not only determined that a card has been inserted falsely orientated into the card reader but it is also determined in which orientation the chip is actually located. Therefore, it is possible to indicate the orientation of the chip and/or of the chip card and to give the user a report on how the user is to correctly insert the card. Further there exists the possibility of so changing the position of the card or the position of the contact elements of the reader that a correct contacting of the chip is possible. 
     The presence of the chip contact surface can be determined inductively, capacitively or by a resistance measurement through direct contacting of the chip contact surface. 
     For the carrying out of the previously described method an apparatus is proposed for determining the orientation of a chip card in the card receiver of a card reader by having a sensor located opposite each of the four possible positions which the chip can take when the card is inserted into the card reader to a test position, with each of the sensors being capable of determining the presence of the chip contact surface and being connected with an evaluation circuit. The test position can correspond to the card reading position. 
     In a first embodiment, the sensors are each formed to provide an inductive recognition of the presence of the chip contact surface. In this case each sensor can include a pair of coils with one coil being a transmitting coil located on one side of the chip card receiver and with the other coil being a detecting coil located on the other side of the chip card receiver, which two coils are connected to one another so as to be in series resonance with respect to an exciting frequency. The alternating voltage applied to the involved transmission coil induces an alternating voltage across the detection coil. If now the chip contact surface comes between such a coil pair it reduces for that sensor the value of the detected alternating voltage. By comparison of the values detected by the four sensors it can be determined at which of the sensors the chip contact surface lies. Therefore, the orientation of the chip card in the card receiver can be clearly determined. 
     In another embodiment, the sensors are each formed to provide a resistance measurement. This can be accomplished in that each sensor has a pair of contact pins which are adjustable in the direction toward the chip card so that the contact pins can be brought into galvanic contact with the chip contact surface. The resistance values determined at the four positions are again compared with one another in the evaluation circuit in order to identify the position of the chip and thereby the orientation of the chip card. 
     Finally there exists the possibility that the sensors can each be formed to carry out a capacitative recognition of the presence of the chip contact surface, in which case for example each sensor has a capacitor with capacitor surfaces arranged on opposite sides of the card receiver. If now the chip card is inserted between the capacitor plates, the capacitance of the involved capacitor is changed by the inserted card material. At the position of the chip contact surface this change is, however, the highest. 
     Advantageously, the evaluation circuit is connected with an indicator device to indicate to the user the orientation of the card or the measures needed to be taken to bring the card into its correct orientation. 
     As the case may be, the evaluation circuit can also be connected with a position correcting device in order to either change the position of the card in the card receiver or the position of the contact elements relative to the card in dependence on the results reported by the sensors. 
     Further features and advantages of the invention will be apparent from the following description which in connection with the accompanying drawings explain the invention by way of exemplary embodiments. The drawings are: 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1, a schematic plan view of one side of a chip card located in a card receiver of a card reader, 
     FIG. 2, a schematic representation of a device for inductively determining the card orientation, 
     FIG. 3, a schematic representation of the sensor arrangement for determining the card orientation by resistance measurements, and 
     FIG. 4, a representation corresponding to FIG. 3 of a sensor arrangement for capacitively determining the card orientation. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     In FIG. 1, the reference number  10  indicates a device, not further illustrated in detail, having a receiving compartment  12 , for a chip card  14 . Embedded in the chip card  14  is a processor or memory component, that is a chip  16  (FIGS.  2 - 4 ), which by means of a chip contact surface  18  arranged on one of the exterior sides of the card can come into contact with non-illustrated opposing contacts of the device located in the card receiver  12 , if the chip card  14  is received in the receiver  12 . In most instances, the position of the chip is the same as the position of the chip contact surface, since the chip is advantageously arranged below the chip contact surface. 
     According to ISO 7816-1 the chip contact surface  18  can take four positions with respect to the chip card  14 , which positions are schematically illustrated in FIG.  1  and designated by reference numbers  18 . 1  to  18 . 4 . The positions  18 . 1  and  18 . 2  thereby are located on the side of the chip card facing the observer, while the positions  18 . 3  and  18 . 4  illustrated with dashed lines are located on the side of the chip card facing away from the observer. One of these four positions is associated with the opposing contacts of the reading device  10 . By a turning of the card about an axis perpendicular to its middle axis or by clapping it about its longitudinal and/or transverse axes the positions  18 . 1 ,  18 . 2  can be transferred to the positions  18 . 3 ,  18 . 4  and vice versa. 
     As a rule, the user does not know at which of the four positions the opposing contacts of the card reading device  10  are arranged, that is in what way he must insert the chip card  14  into the card receiver  12  in order to achieve a contact between the chip contact surface  18  and the opposing contact elements of the card reading device  10 . If clear instructions are not given on the device as to in what orientation the chip card  14  has to be inserted into the card receiver  12 , a high probability exists that the user will at first insert the card into the card receiver  12  in a false position. The arrangement illustrated in FIGS. 2-4 permits the orientation of the inserted chip card  14  to be correctly recognized, and as the case may be to be quickly corrected in order to avoid a number of false insertions. 
     FIG. 2 shows a sensor arrangement for inductively determining the position of the chip contact surface  18 . This sensor arrangement has four sensors indicated generally at  20 , of which in FIG. 2 only two sensors are seen, since the other two are hidden. Each sensor has a transmitting coil  22 , which is connected with a source  24  of alternating voltage. Associated with the transmitting coil  22  is a receiving coil  26 , which is connected with an evaluating unit  28 . The evaluating unit is in turn connected with an indicating device  30 . 
     The transmitting coil  22  and the receiving coil  26  are in series resonance with respect to the frequency of the exciting voltage. The alternating voltage applied to the transmitting coil  22  induces likewise across the receiving coil  26  an alternating voltage. If now the chip contact surface  18  is between such a coil pair  22 , 26  the value of the alternating voltage across the receiving coil  26  is lowered. This voltage value change is amplified by an operational amplifier in the evaluation unit  28  and by comparison with the signals obtained from the other sensors  20  is recognized and evaluated. Therefore it is possible to clearly recognize the position at which the chip  16  is located and thereby also the orientation of the chip card  14  in the receiver  12 . This orientation can be indicated by the indicating unit  30 . At the same time or alternatively thereto the indicating unit  30  can also give information to the user as to how the orientation of the card must be changed in order to bring the chip contact surface  18  into contact with the opposing contact elements of the card receiver  12 . 
     The testing of the orientation of the card  14  in the card receiver  12  can take place at the effective contact position of the card or also at a desired test position inside of the card receiver which is displaced in respect to the effective contact position. It is to be noted that the necessary value testing of the four coil pairs or sensors  20  should not occur until stopping of the movement of the chip card  14 , since for example metalized holograms, which are often provided on chip cards, during movement of the card can likewise-lead to voltage disturbances. 
     FIG. 3 shows a modified embodiment in which a sensor  32  is arranged at each of the positions  18 . 1  to  18 . 4 , which sensor  32  consists of two contact pins or sensing points  34  connected with one another through a non-illustrated resistance measuring circuit. These pins or points can be moved in the direction toward the chip card  14 , that is in FIG. 3 moved up or down. Upon the contact pins  34  coming in contact with the plastic material of the chip card, a high resistance value is reported. If the contact pins  34  encounter the metallic chip contact surface  18  a lower measured resistance value is obtained. This resistance value is determined by the gold plated surface and therefore can be distinguished for example from the resistance value of a metalized hologram. By means of a comparison of the resistance values obtained from the four sensors  32  again a clear position of the chip contact surface  18  and of the chip  16  can be determined and evaluated. 
     Finally, FIG. 4 shows a sensor arrangement for a capacitive recognition of position of the chip  16  and of the chip card  14 . In this arrangement a sensor  36  is again arranged at each of the positions  18 . 1  to  18 . 4 , of which only two are illustrated in FIG.  4 . Each sensor  36  represents a capacitor with two electrodes  38  which are located on opposite sides of the chip card  14 . By the insertion of the chip card between the electrodes  38  of the sensors  36  the dielectric value is changed and thereby also the capacitance of the sensors  36 . At the position at which the chip contact surface  18  is located this change is the highest. By comparison with the other sensors again the position of the chip  16  can be determined and indicated on the indicating device  30 . Also in this embodiment care is to be taken in that a capacitance change arising from metalized holograms is also recognized. 
     LIST OF REFERENCE NUMBERS 
     
       
         
               
               
               
             
           
               
                   
                   
               
             
             
               
                   
                 10 
                 Card reading device 
               
               
                   
                 12 
                 Receiving compartment 
               
               
                   
                 14 
                 Chip card 
               
               
                   
                 16 
                 Chip 
               
               
                   
                 18 
                 Chip contact surface 
               
               
                   
                 18.1-18.4 
                 Chip positions 
               
               
                   
                 20 
                 Sensor 
               
               
                   
                 22 
                 Transmitting coil 
               
               
                   
                 24 
                 Alternating voltage source 
               
               
                   
                 26 
                 Detection coil 
               
               
                   
                 28 
                 Evaluation unit 
               
               
                   
                 30 
                 Indicating unit 
               
               
                   
                 32 
                 Sensor 
               
               
                   
                 34 
                 Contact pins 
               
               
                   
                 36 
                 Sensor 
               
               
                   
                 38 
                 Electrodes