Method for contactless information transmission.

The invention relates to a method and an apparatus for contacting information transmission between a data carrier and a data reader, said data transmitter and data readers are location-independent to each other and brought together for information transfer.

The invention further relates to a device for contactless power transfer, and a device for contactless modification of the electronic memory of the data carrier.

From DE-PS 31 49 789 a device is known which is referred to therein as a inductive identification information and is particularly suitable for the interaction of an electronic key with a lock. In this device vibrates in the lock an oscillator and the high-frequency vibration is picked up at the approach of the key of this and modulated with a serving as a key identifier frequency or pulse pattern, transferred back to the castle, and processed by an electronic identification device in the lock on. The return transmission of high-frequency vibration occurs via coils, ie inductively.

Such inductive transmission is possible with a lock-key system, because even in the key is enough space for a coil. However, a disadvantage is the relatively large stray field of the coil, whereby the transfer is very lossy. Moreover, in many other data storage devices, if these are flat, such as associated with a credit card, the placement of a coil is either not possible or too great a thickness of the data carrier.

The present invention is therefore based on the object to provide a device for contactless information transfer, has the low transmission losses and is also suitable for flat disk. The invention will also allow for energy transfer and the change of the electronic memory from disk.

This object is inventively achieved in that for transmitting information capacitive coupling of at least two conductive paths between the data carrier and data reader is prepared.

An apparatus for carrying out the method is characterized in that the disk is formed on its surface with at least two sheet-like electrodes, and in that the data reader is formed with at least two sheet-like electrodes which are brought together for information transfer in such a manner with the electrodes of the data transmitter, that they forming capacitors, through which at least one common circuit is made for carriers and data readers.

The inventive solution is not limited to the transfer of information from a data carrier to a data reader. Rather, the data reader can also be formed at the same time as the data transmitter and the data carrier can be adapted to receive or altering its information accordingly.

Further advantageous embodiments of the invention will become apparent from the dependent claims.

The invention will be explained in the following with reference to embodiments shown in the Figures 1 to 10 in more detail. show case<ul><li>FIG. 1 illustrates the basic principle in a very simple form of execution,</li><li>FIG. 2 is an enlargement of the arrangement shown in Figure 1 for a greater number of coding possibilities,</li><li>FIG. 3 is a simplification of the arrangement shown in Figure 2 with serial data transmission,</li><li>Fig. 4 shows a data carrier with matrix-like arrangement of the electrodes,</li><li>Fig. 5 shows an embodiment with clock transmission of information processing and transmission,</li><li>Fig. 6 shows an embodiment with a separate path for transmitting information,</li><li>Fig. 7 shows an embodiment in which the content of the data carrier can be changed,</li><li>Fig. 8 shows the structure of a memory unit,</li><li>FIG. 9 is a program for protecting a storage unit and</li><li>Fig. 10, an application example for the identification of parts on their surface.</li></ul>

1 illustrates the principle of the invention is shown in a very simple embodiment. The disk (10) has maps form as is used eg in check card. Figure 1 shows the disk in section, its cross section is drawn too thick in favor of a clear representation. The data carrier (10) has on its surface two laminar electrodes (11,12), which are arranged with one in the interior of the data carrier (10) code resistor (13) via lines (13a, 13b) are connected. The disk is inserted for information transmission in the slot (15a) of the data reader (15), in which two electrodes (16,17) are arranged so that they are in an inserted data carrier (10) with the electrodes (11,12) are congruent and capacitors (C1, C2) form, between the electrodes is an air gap. The electrodes (16,17) in the data pickup means (15) are connected to an alternating current generator (18) and a measuring resistor (19) via lines (18a, 18b) connected.

The two capacitors (C1, C2) form with the coding resistor (13) and the measuring resistor (19) has a so-called. Complex circuit, in which the measuring resistor (19) falling voltage U_M for a sinusoidal generator voltage U_G is given by the equation U_M = R_M ((R_C + R_M) ² + 4 / ω²C²)^-1/2 U_G It is R_M = The value of the measuring resistor (19) R_C = The value of Codierwiderstandes (13) ω = angular frequency of the generator (18) C = the capacitance of the capacitors (C1, C2) U_G = Voltage of the generator (18).

can be used as oscillator also a square wave generator.

The voltage U_G the generator (18) and its frequency f, or angular frequency 2.pi.f, can be preset. By a sufficient mechanical guidance of the data carrier (10) in the slot (15a) of the data reader (15) can be achieved that the capacitance C of the capacitors (C1, C2) varies only assignable limits. Considering these limitations, there is a clear correlation between the value of Codierwiderstandes (13) and the voltage drop across the sense resistor (19). That is dependent on the accuracy of the mechanical guide (and the accuracy of the thickness of the disc), a more or less large number of values ​​of Codierwiderstandes (13) by the voltage drop U_M differed across the sense resistor (19) safe and be processed in the evaluation device (19z).

As will be explained below with Figure 7 in detail, the data reader (15) can also be simultaneously formed as a data encoder. In this case, the data carrier (10) in place of the resistor (13) contains an electronic memory.

If the disk (10) contains only unchanging information in the form of resistors, to an increase in the number of coding options through the embodiment illustrated in Figure 2 can be achieved. With this, the data carrier (20) includes a plurality of Codierwiderstände (23a, 23b to 23n), for example eight pieces, one of which (22b to 22n 22a) is connected each to the common electrode (21) and with individual electrodes. The data reader (25) contains the congruent common electrode (26) and the congruent individual electrodes (27a, 27b to 27n). The latter are connected to the generator (18) on the individual measuring resistors (29a, 29b to 29n) connected in parallel which are taken at n different signals for the evaluation unit (29z). In this way, the number of coding options can significantly increase.

Another way of increasing the number of Codiermõglichkeiten is shown in FIG. 3 Here the data carrier (30) also comprises a common electrode (21) and n individual electrodes (22a, 22b to 22n). However, the data reader (35) includes only two electrodes (16,17) and only a measuring resistor (19). but the data reader still contains a (not shown) motor, which moves the data carrier (30) during the read operation in the direction of arrow (38), so that the individual information time-sequentially (serially) on the measuring resistor (19) for the evaluation device (39Z ) present.

3 shows, in addition, another embodiment of the Codierwiderstände. They consist of only switches (33a, 33b to 33n), or continuous or open connections. Because with them only two different states can be seen, the evaluation of the measuring resistor (19) occurring signals can be carried out particularly easily.

The embodiments illustrated in Figures 2 and 3 can also be combined with each other. For this purpose, the data carrier (40) shown in Figure 4 on one side has a matrix of, for example, 8 × 4 individual electrodes (42) and information transmission takes place, for example, in the direction (48a) parallel and in the direction (48b) in which the disk is moved serially. If, in an 8 × 4 matrix only Codierwiderstände with the values ​​"pass" and "do not pass", then arise already at this layer in construction very simple to produce disks over 4 billion code.

The novel process can be not only simply structured data carriers - as illustrated in Figures 1 to 4 - apply, but also for data carriers with significantly more complex architecture. The coding resistor (13) in the Prinzipd ESCRIPTION of Figure 1 can be varied over time, for example in the form of pulse modulation. Here, all known types of modulation of communications technology can be used as pulse position modulation, pulse pause modulation and pulse code modulation. For this, the disk not only receives a memory module for coding, but also other electronic devices such as clocked networks, counters, decoding logic or microprocessors. Regardless of the various implementation options two characteristics are necessary: ​​the transmission of power to the data carrier and the provision of a clock in the data carrier.

One possible embodiment for the transfer of energy and a clock in the data carrier for the information processing and transmission is shown in FIG. 5 In this example, the electrodes (11,12) of the data carrier (50) via a rectifier arrangement consisting of the diodes (D1, D2, D3, D4) is connected to each other. At the outputs of the rectifier is a pulsating DC voltage which is smoothed by the capacitor (K) and with the zener diode (Z) is restricted. This DC voltage supplies the memory unit (53).

The clock signal (54a) whose frequency by the generator (18) is predetermined, is taken off between the electrode (12) and the negative rectifier output and the clock input (53a) supplied to the memory unit (53). The storage unit is controlled by the clock the contents of their electronic memory at the data output (53b) serially. This output signal (54b) is supplied to the transistor (T1) is fed, which modulates the internal resistance of the data carrier (50) by short-circuiting the positive half-waves in the presence of a high level of the output signal (54b). Here are dependent on the scan rate of the clock (54a) by the memory unit (53) always successively shorted several positive half-waves.

The short circuit of the half-wave is detected the data reader at the measuring resistor (19) and processed in the evaluation unit (59Z). The storage unit (53) can be embodied in many embodiments in the known art; one possibility is described in more detail with FIG. 8

Figure 6 shows a further embodiment of the invention, in which a separate channel is provided for transmission of the information. Hierfur the data carrier (60) has a third sheet-like electrode (62) and said data reader (65) corresponding to a third congruent electrode (67). In this case, the measuring resistor (19) is traversed only by the reader to the data (65) transmitted signal, the evaluation of its voltage drop in the evaluation unit (69z) is considerably simpler than in the example illustrated in FIG. 5 Additional property almost all the energy that is transferred into the data carrier, for operations in the data carrier medium, since the transmission of information in the data reader in this embodiment requires little energy. Unlike Figure 5, the internal resistance of the channel information is only modulated. The For used PNP transistor (T2) having its emitter to the positive output of the rectifier and can be controlled via a defined base-emitter voltage.

Otherwise, the circuit of Figure 6 of the circuit in Figure 5, as is apparent from the same indicator.

7 shows a particularly advantageous embodiment of the invention is shown, in which the content of the data carrier (70) can be changed. Given the resistance (79) is not only - used to decrease the voltage drop on him for the read operation, but the resistance (79) itself, for example with a switch (79a), modulated and this modulation is in - as in the previous embodiments data carrier (70) at the emitter of the transistor (T3) removed. It expediently the data transfer to the data carrier (70) and the data reader and lender (75) is separated in time.

As in the preceding exemplary embodiments of the generator (18) generates in this case a clock signal, which is supplied via the electrode (12) of the storage unit (73) at the clock input (73a). This clock signal is modulated by the switch (79a) such that always a plurality of clock pulses to receive a higher or lower voltage, which are supplied to the data carrier (70) via the electrode (62). Through the diode (D7) and the low-pass filter composed of the resistor (R7) and capacitor (C7), the high frequency modulated clock signal is demodulated and then the write input (73c) of the storage unit (73) supplied. Also in this case, the memory unit is designed in known technology and can be implemented for example with the most single chip microprocessors, wherein an electrically programmable and erasable memory is used for data storage.

In Figure 8, an exemplary embodiment of the storage unit (73) is illustrated. In this, a microprocessor or controllers Valvo PCB 84COO and an electrically programmable memory (E PROM) Valvo PCB is used 8582nd With (+) and (-) the voltage supply for both components is labeled. The input (83a), the clock signal for the microcontroller is supplied. Of the 8 lines of the port entrance (83c) only an arbitrary line is used as a write input. Likewise, from the 8 lines of the port output (83b) is used only an arbitrary line. exists between the microcontroller and the E²PROM a compound (SCL) for the serial clock signal of the microcontroller, and a bi-directional connection (SDA) for the serial data transmission to and from the E²PROM.

If the storage unit (73) is used as a storage unit (53) for the 5 and 6, of course, does away with the write input (83c).

In an advantageous embodiment, the E²PROM is replaced by a custom component that is illustrated in FIG. 9 With it can be prevented by a special write information or a last program step further programming. The customer-specific component (91) has as any electrically programmable memory, a control unit (92) which is connected to the memory array (95) on the following lines connected: a bidirectional serial data line (SDA), the address lines (ADRY) and (ADRX) to the row register (93) and said column register (94), a line (rEAD) for the read signal and a line (WRITE) for the write signal. The latter line is for the protection Schreib13 example via an AND gate (97) with the last line (96) of the memory matrix (95) linked. Once this line is described with corresponding information, which their associated input of the AND gate (97) is always set to "0", so that for the entire memory array (95) is no longer a write operation possible.

Such programming protection can also be designed for specific areas of the memory array, so that protected and unprotected areas are possible simultaneously.

The embodiments for the disk represented are - as already mentioned - for credit cards, but also for any other type of flat disks, such as identity cards, cards for access or usage control cards to open doors, etc. The exemplary embodiment described with figure 7 is particularly suitable for such a disk, in which a variable value, such as an account balance to be updated each time.

Another example of the application is shown in FIG. 8 identified moving in this are on a conveyor belt (100) in direction (100a) workpieces (101) and / or provided with additional data. This is adhered to each workpiece (101), a data carrier (102) on which two or more electrodes are disposed on the same side (103). A data reader or data readers and-encoder (105) is brought eg by (not shown) touch sensors so the workpiece (101) that its electrodes (106) to the electrodes (103) of the disk (102) on the workpiece in low distance face and can be carried out for the read and the read and write operation.