Abstract:
The invention relates to a switching device ( 1 ) for the keyless activation or deactivation of a consumer, especially an engine or the like in a vehicle, and/or for unlocking or locking a functionally essential component of a vehicle. Said device comprises at least one switching element ( 3 ), arranged inside a housing ( 2 ), which can be actuated by an actuation element ( 4 ), thereby generating at least one switching signal for the control unit ( 10 ). The aim of the invention is to provide a switching device which consists of only few components and which is incorporated into a keyless security system in a simple manner. For this purpose, an electrode ( 5 ) is provided on the housing ( 2 ) and is connected to the control unit ( 10 ). Said electrode ( 5 ) transmits data to a mobile ID transmitter ( 13 ) and the electrode ( 5 ) allows data being transmitted to a mobile ID transmitter ( 13 ) via a capacitative coupling ( 32, 34 ). The control unit ( 10 ) transmits a first encoded and/or modulated signal to the electrode ( 5 ) when the latter receives a first switching signal from the switching element ( 3 ). The invention also relates to a security system ( 25 ) for the keyless activation or deactivation of an installation or a device, especially of a steering wheel lock or of an engine in a vehicle. Said system comprises a switching device ( 1 ) according to the invention, and a mobile ID transmitter ( 13 ), capacitative data transmission between the switching device ( 1 ) and the ID transmitter ( 13 ) being possible, and a control unit ( 10 ) which controls data transmission between the switching device ( 1 ) and the mobile ID transmitter ( 13 ).

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention is directed toward a switching device for keyless switching on or switching off a load, especially an engine, etc., in a vehicle, and/or unlocking or locking a vehicle component essential to function. Such a device is provided, for example, in the interior of a vehicle, preferably within reach of a driver, and is incorporated in a security system, especially of a vehicle. Various switching processes can be performed by the switching device. 
         [0002]    The invention is also directed toward a security system for keyless activation or deactivation of a unit or device, especially a steering-wheel lock or an engine in a vehicle. 
       BACKGROUND OF THE INVENTION 
       [0003]    Unexamined patent application DE 198 38 992 A1, which discloses a starter switch for vehicles with electronic steering lock, is known from the state of the art. This ignition starter switch is operated like a comparable mechanical ignition key during starting or stopping of the engine. Since this ignition starter switch also functions in a keyless manner, a transmitting and receiving device is additionally provided that serves to identify an authorized user and, after identification, unlocks the ignition starter switch, so that it is freely operable. The ignition starter switch itself is unlocked or locked by an additional electromechanical lockout controlled by a control unit inside the vehicle. Actual release for unlocking is produced by a mobile ID transmitter (electronic key). Because of the prescribed electromechanical locking of the ignition starter switch, the number of mechanical components is additionally increased, so that the weight of the switch and the required manufacturing costs are significantly increased. 
         [0004]    Another type of ignition starter switch is disclosed in unexamined patent application EP 1,468,884 A2. No mechanical lockout device is provided in this ignition starter switch to rule out unauthorized operation of the switch. This ignition starter switch is also incorporated in a security system, the switch being additionally provided with a coil antenna, in order to direct a so-called wakeup or activation signal by radio waves to a mobile ID transmitter as soon as the switch is activated. Starting of the engine is then possible only if the required identification code is sent by the ID transmitter and checked on the vehicle side by a control unit and recognized as admissible (in the sense of correct). 
         [0005]    If the correct identification code is involved, the additional switching commands that start from the switch can be conveyed and converted by the corresponding electrical or electromechanical components or devices in the vehicle. It has been found in practice that security systems based on radio can be bypassed by a radio link extension. Such a system can be bypassed particularly simply if the wakeup or activation signal on the vehicle side, which generally only has a range of a few meters, is extended to the actual location of the mobile ID transmitter, since this then independently emits the far-reaching identification signals of the vehicle. 
         [0006]    In order to avoid the radio link extension in security systems just described, systems have recently been in use, in which data exchange occurs through a capacitive coupling. For example, one such security system is further described in unexamined patent application DE 101 32 031 A1. However, this security system is exclusively directed toward an access authorization system, in order to release access to a protected area only in case there is a positive identification. 
       BRIEF SUMMARY OF THE INVENTION 
       [0007]    The present invention provides a switching device that consists of few components and is simply incorporated in a keyless security system. The present invention also provides an improved and simple security system for keyless activation or deactivation of a unit or device, especially in the area of vehicles. 
         [0008]    According to the invention, the switching device has an electrode on the housing that is connected to a control unit, the electrode serving for data transmission to a mobile ID transmitter (electronic key or electronic identification device). This electrode permits, by capacitive coupling, data transmission to the mobile ID transmitter, whereby the control unit sends a first coded and/or modulated signal to the electrode when it receives a first switching signal from the switching element. The present switching device is therefore also used to send the activation or wakeup signal to the mobile ID transmitter. This signal is not transmitted by an inductance or electromagnetic waves, but by means of the capacitive electrode, through which capacitive coupling with the ID transmitter is possible. As soon as the mobile ID transmitter receives this capacitive signal, it sends, for example, an identification signal, especially a radio signal at 433.22 MHz or 868 MHz, to the electronics inside the vehicle, in order to release the security system. In this method, the actual capacitive signal is transmitted directly by the body of an operator or driver. As soon as the operator wishes to use the switching device to switch on or switch off a device, he must, on the one hand, touch the operating element, so that capacitive coupling occurs to his body. On the other hand, capacitive coupling between his body and the mobile ID transmitter can occur if the operator carries the mobile ID transmitter with him. For this purpose, the mobile ID transmitter is also equipped with an electrode. Through indirect contact between the operating element and the mobile ID transmitter by the body of the operator, capacitive coupling then occurs between the two parts, which is simultaneously used for data transmission. It is then not necessary for the operator to touch the two electrodes for capacitive data transmission directly. Advantageously, electrical insulation is provided between the electrodes (in the switching device and in the ID transmitter) and the operator. The actual data signal flows as a weak current of a few microamperes through or over the human body of the operator, specifically from the source to the destination. It is therefore not possible to query this data signal from the outside without authorization. Consequently, much higher security is guaranteed than in ordinary radio transmission of the activation or wakeup signal. It is also conceivable to convey the identification signal in reverse from the ID transmitter to the switching device by capacitive coupling to the security system. 
         [0009]    Because of the switching device according to the invention, operator comfort of a vehicle can be further increased, since during activation of the switching device, an identification process for the switching signal occurs simultaneously. Only with correct identification, is the signal sent from the switching device to the control unit further processed, so that the engine-management system or other devices are activated or deactivated. 
         [0010]    For example, a vehicle can also be started without operating an ignition key in an ignition lock, since the required identification automatically occurs by the operating element merely being touched by the operator. This type of system is also called a “passive drive system.” In this case, a mobile ID transmitter can be used simultaneously not only for a so-called “passive entry system,” but also for a “passive drive system” for keyless activation or deactivation of a device, such as starting a load and/or unlocking and locking a vehicle component essential to function. Naturally, present security devices, such as an electrical steering-wheel lock and/or an electrical immobilizer, can also be used in order to secure the vehicle against theft. Activation or deactivation of these security devices occurs as a function of the corresponding switching signal (the switching device) by the control unit, if the correct identification signal is sent to the control unit by the mobile ID transmitter. 
         [0011]    In this way, an ordinary ignition lock with ignition key (switch position  0  to III) can be replaced with a one-stage switching device (switching states  0  and I), since the functionality or desired control process can be stipulated by the control unit. This control process can be stored as a program in the control unit. For example, authorized access to the vehicle can correspond to switch position I of an ordinary ignition lock. Brief activation of the switching device or stepping on the brake pedal can serve for switching engine management or the ignition on, for unlocking the steering wheel lock and/or the immobilizer, and for activation of additional electrical loads, comparable to the switch position II of an ordinary ignition lock. Further operation of the switching device can then lead to starting the engine, comparable to switch position III of an ordinary ignition lock. It is also conceivable that the engine-management system and the engine are activated when, for example, the brake pedal and the switching device are operated simultaneously. When the switching device is further operated, the engine and the engine-management system can be switched off again (switch position I of an ordinary ignition lock). Leaving and/or locking the vehicle can serve to switch the electrical loads off, comparable to switch position  0  of an ordinary ignition lock. 
         [0012]    In a special embodiment of the switching device, the switching element has different switch positions, a distinct switching signal being assigned to each switch position, which is sent to the control unit by operating an operating element. It is possible to form not only the states on and off, but additional or comparable switching states can also be formed, as in an ordinary ignition lock. For this purpose, the switching element can consist of an ordinary raster, key, switch, rotary switch, etc., in order to form the different switching states that are necessary. It is then particularly desirable if operation of the switching device takes place in a manner comparable to an ordinary ignition lock. For this purpose, the switching element can assume different switch positions by a translatory and/or rotary movement of the operating element. For this purpose, combined keys and rotary switches can be used as switching elements. It is also conceivable that two or more switching elements are arranged in a switching device connected to the control unit. Additional possibilities for using the switching device can be produced thereby. For example, it is conceivable that programming of a navigation system (GPS system) is possible only if the operator has been identified by the mobile ID transmitter. Use of a radio telephone can also be secured by such a switching device. Naturally, other application possibilities are also conceivable for this switching device. 
         [0013]    As already mentioned, capacitive coupling occurs between the electrode (on the vehicle side) provided in or on the switching device according to the invention and the mobile ID transmitter, if electrical insulation is provided on the corresponding capacitive electrode. The housing or the operating element of the switching device can be used as electrical insulation for this purpose. The housing of the mobile ID transmitter can also be used as electrical insulation for the capacitive electrode in the ID transmitter. For this purpose, corresponding electrodes are arranged inside the housing. The electrical insulation can preferably consist of a non-conducting plastic. 
         [0014]    In order to accommodate the capacitive electrode in the switching device optimally, it can be made in several parts, the individual parts of the electrodes being connected in an electrically conducting manner to one another. The electrode can be arranged, on the one hand, in the operating element and, on the other hand, in the housing of the switching device. The electrode is configured in plate and/or film-form for optimal capacitive coupling. It has proven to be appropriate to arrange the electrode over a large area behind the surface of the operating element and/or the housing. For this purpose, the electrode can be mounted on the back on the inside surface of the operating element. It is also conceivable to arrange the electrode directly in the housing or the operating element. The electrode itself can consist of an electrically conducting metal. 
         [0015]    To obtain the most detailed possible information concerning individual switching processes or switching states of the switching device or individual device in the security system or in a vehicle, an optical and/or acoustic display element can additionally be present in the switching device. This display device can be provided, on the one hand, in the operating element and/or, on the other hand, in the housing. The display device itself can be an LED or a display, etc. It should be mentioned in this context that the operating element can generally be at least mechanically operated, but not all functions need to be included in the corresponding switching positions, since these depend on whether the operator can be identified as authorized by the corresponding mobile ID transmitter. Consequently, arbitrary operation of the switching device is conceivable, which, however, does not lead to any functional triggering if the operator is not carrying the ID transmitter. 
         [0016]    If the above-mentioned display device is used, a film can also be used that has transparent areas. An inscription, symbol, etc., can be displayed in the switching device by a simple light source through these transparent areas. For example, the operating element can be illuminated or shown from the rear through the display element. In order to be able to blend an inscription in, for example, the area of the inscription must be transparent in the film. For this purpose, a metal foil can have corresponding recesses punched, lasered, etched or incorporated in some other way. The transparent areas can be generated in this way. It is also conceivable to configure this film to be electrically conducting, whereby metal or plastic films can be used that simultaneously serve as (capacitive) electrodes for data exchange. It is also conceivable to use a luminescent film for display of the display element as an electrode for data exchange. The advantage of an electrically conducting film as an electrode is seen in the fact that it is arranged directly behind or in the operating element, so that shielding of the conducting surface of the film by additional interfering objects is essentially avoided. 
         [0017]    Another variant of the switching device can also have a sensor element with a support surface, whereby a test object, especially a finger of an operator, can be placed on the support surface, which can be identified by the sensor element. Such a sensor element is disclosed, for example, by unexamined patent application EP 0,805,247 A1. The required support surface of the sensor element can be provided, for example, on the surface of the operating element. The surface of the housing can also serve for arrangement of the support surface. An additional security query can be conducted by the additional sensor element. It is then also conceivable that only the sensor element serves in the switching device for identification of an authorized operator, if, for example, the mobile ID transmitter should be defective. Since the operator must operate the operating element in any case when he intends to start the engine of a vehicle, for example, no additional step or operation is necessary for him to release the engine-management system, an electrical steering-wheel lock, etc. 
         [0018]    The switching device according to the invention appropriately also has a power transmission unit, so that electrical power can be transmitted from the switching device to the mobile ID transmitter in such a way that it remains functional without its own power supply or during failure of its power supply. Mobile ID transmitters often have a mechanical key, in order to permit access to a vehicle or secured area during battery failure. However, the security system cannot permit activation or switching on of the device in question without identification of the ID transmitter. It is ensured by the power transmission unit in the switching device that the ID transmitter also has the necessary power, if, for example, its battery is too weak. An inductive or capacitive power transmission can occur for this purpose, for which a coil or electrode in the switching device and ID transmitter are provided. If the operator now finds that the ID transmitter, because of a power deficiency, no longer operates perfectly, he can bring the ID transmitter into the vicinity of the switching device, so that power transmission is made possible and the security system can permit release of the device in question by identification of the ID transmitter. 
         [0019]    The switching device according to the invention, because of its space-saving configuration, can also be arranged in or on the steering wheel itself, especially in the area of an emblem or the area of impact or gripping surfaces. Only one or a few electrical conductors emerge from this switching device, so that simple cabling itself is possible in the steering wheel. The switching device according to the invention therefore need not be arranged to be hidden and scarcely accessible, like a mechanical steering-wheel lock. It is even conceivable to arrange the switching device on the gear lever, on a center console, on a multifunctional operating unit on the dashboard, on an inside panel of a door, on the roof liner, on the inside of the rearview mirror or on the left or right of the steering wheel in the vehicle. Operating comfort during starting of the engine, etc., can thereby be significantly increased, since the ergonomic requirements of the driver can be considered. 
         [0020]    The present invention is also directed toward a base security system for keyless activation or deactivation of a system or device, especially a steering-wheel lock (which is considered a functionally important component in a vehicle) or an engine in a vehicle. This security system is equipped with a switching device according to the invention and a mobile ID transmitter, whereby capacitive data transmission can occur between the switching device and the ID transmitter. A control unit that controls at least data transmission through the switching device and mobile ID transmitter is additionally provided on the security system. In this security system, the driver or operator of the vehicle need not be actively identified in order to release or activate the system. Only by operating the switching device, especially the operating element, is the identification process automatically started, in which case capacitive data transmission is used to transmit the coded wakeup or activation signal from the switching device to the ID transmitter. After the mobile ID transmitter has received and checked this wakeup signal, it sends the actual identification code back to the security system. This can also occur, on the one hand, by capacitive data transmission or by an additional receiving unit that receives the identification data by radio from the mobile ID transmitter and conveys it to the control unit. The control unit then compares the identification data (regardless of whether it was received by radio or by capacitive data transmission) with the stipulated identification data and then performs a corresponding check of the individual loads or devices in case of positive identification, depending on which switch position or which switch signal of the switching device is present. For example, the electrical steering-wheel lock can be unlocked and the engine-management system can be released, in order for the engine in a vehicle to be started. 
         [0021]    The mobile ID transmitter can also be used for keyless access to a blockable area, especially the interior of a passenger compartment interior, in which the ID transmitter is also incorporated in the access-control system of the vehicle. To increase operational security (in this case, not theft), an electrode can additionally be provided in the driver&#39;s seat of a vehicle, which is also connected to the control unit, the electrode serving for capacitive data transmission to the mobile ID transmitter. It is thereby possible that starting a load in the vehicle is only possible if the operator, who is carrying the mobile ID transmitter, is also actually sitting in the driver&#39;s seat. Unintended starting of the engine can be prevented by this means. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0022]    Additional measures and advantages of the invention can be seen from the claims, the following description, and the drawings. The invention will be presented in several embodiment examples in the drawings. In the drawings: 
           [0023]      FIG. 1  shows a schematic overview of the security system according to the invention, with the switching device essential according to the invention, 
           [0024]      FIG. 2  shows a side view of the switching device according to the invention in partial section, with an operating element to be operated in a translatory manner, 
           [0025]      FIG. 3  shows a side view of another switching device according to the invention, with an operating element to be operated in a rotary manner, in a view comparable to  FIG. 2 , 
           [0026]      FIG. 4  shows a top view of the switching device from  FIG. 3 , 
           [0027]      FIG. 5  shows a side view of a comparable switching device from  FIG. 2 , but with another arrangement of the capacitive electrode and an integrated power-transmission unit, and 
           [0028]      FIG. 6  shows a top view of another switching device, with an integrated display element. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0029]    An overview of a security system  25  is shown purely schematically in  FIG. 1 . This drawing shows only the essential electronic and mechanical components. In a secured area, such as a the interior space of a passenger compartment, the switching device  1 , as well as the control unit  10 , the receiving unit  11 , and the management system  12 , are arranged. This can preferably be a so-called “passive keyless drive system”, which is used, for example, as a supplement to a so-called “passive keyless entry system.” The same mobile ID transmitter  13  can then be used for both systems. This mobile ID transmitter  13  is an electronic identification device that replaces the mechanical key of ordinary security systems. After the operator  30  has achieved access to the secured area, keyless activation of a load, for example, an engine in the vehicle and/or unlocking of an electric steering-wheel lock, is also to be produced by the security system  25 . For this purpose, the operator  30  need only operate the switching device  1  with the corresponding operating element  4 . Through the required touching of the operating element  4 , capacitive coupling occurs between the switching device  1  and the mobile ID transmitter  13  carried by the operator  30 . For this purpose, the switching device  1  has an electrode  5  arranged in or on the switching device  1 . Another electrode  22  is also provided in the ID transmitter  13 , so that capacitive coupling occurs between the operator  30  and the mobile ID transmitter  13 . The operator  13  himself therefore represents the connection element between the electrode  5  in the switching device  1  and the electrode  22  in the ID transmitter  13 . The operator  30  himself is represented as the resistor or resistors (R) with reference number  31  in the circuit diagram. In the overview picture (see  FIG. 1 ), depiction of the ground connection of the system is omitted. The elements  22 ,  15 ,  16 ,  17  shown in the ID transmitter  13  are generally not visible, since they are situated within the housing of the ID transmitter. 
         [0030]    If the operator  30  now presses on the operating element  4  with his hand or finger, capacitive coupling automatically occurs between electrode  5  and the finger. This capacitor (C 1 ) bears reference number  32 . The signal being transmitted capacitively consists of an electrical alternating field conveyed over the skin of operator  30 . This alternating field can be generated by an oscillator, for example, in the switching device  1  or the control unit  10 . The mobile ID transmitter  13  receives this capacitive signal through its electrode  22 , which can be arranged within its housing when the operator  30  carries the ID transmitter with him. The capacitive signal can itself be coded or keyed. If the ID transmitter  13  has identified the signal received from switching device  1  as an admissible wakeup or activation signal, it, in turn, sends an identification signal back to the control unit  10 . This can also be a capacitive signal that is sent back in the same way as the already mentioned wakeup signal. It is also conceivable that the mobile ID transmitter  13  sends a radio signal through a radio link  21  to a receiving unit  11 . This receiving unit  11  then sends the received signal to the control unit  10  for evaluation. For this purpose, the receiving unit  11  is connected to the control unit  10  by a connection  20 . If the identification signal is sent back to the switching device  1  through a capacitive coupling, the receiving unit  11  in the security system  25  can be omitted. 
         [0031]    The identification signal received from the mobile ID transmitter  13  is now compared or evaluated in the control unit  10 . If it is then found that the mobile ID transmitter  13  has sent the correct identification signal, the actual switching state (for example,  0  or I) of the switching device  1  is considered by the control unit  10 , in order to send a corresponding activation or deactivation of a load or corresponding control signal to another unit, such as the (engine-)management system  12 , so that the engine can be started. The electrical steering wheel lock and/or the electrical immobilizer can thereby also be unlocked previously or simultaneously. 
         [0032]    To switch the engine off, an additional operating of the switching device  1  can be used, which then sends the switching signal to the control unit  10 . The control unit  10  compares the received switching signal with the current engine state and sends a switch-off signal to the engine management system  12 , if the corresponding identification signal has been found beforehand by the ID transmitter  13 . Switching off of the engine is possible in this case. 
         [0033]    Switching on and switching off an engine, as well as securing and unlocking a vehicle, can be depicted by the corresponding switching states of the switching device  1  as an ordinary mechanical ignition-lock switch. For example, it is then conceivable that only locking of the electrical steering-wheel lock occurs when the mobile ID transmitter  13  is no longer situated in inside the vehicle. 
         [0034]    Additional electrodes that are acted upon by a capacitive activation signal in a specified time interval can be provided to locate the ID transmitter  13  in the secured space or vehicle interior. As soon as the ID transmitter  13 , after receiving the activation signal, is reported by its identification signal, the system  25  establishes the electrode of the ID transmitter with which it is in capacitive connection. The position of the ID transmitter  13  can be clearly determined by this. It is then conceivable that available electrical lines and/or electrically conducting surfaces, such as mirror surfaces, chrome surfaces, etc., in the vehicle are used as additional electrodes for location of the ID transmitter  13 . It can also be established by the system  25  whether an additional ID transmitter  13  is also present inside the passenger compartment, carried, for example, by a passenger. 
         [0035]    The security system  25  can optionally be equipped with an additional electrode  18  arranged in the driver&#39;s seat  19 . Through this security electrode  18 , it can be established by the security system  25  whether the operator  30  is actually situated on the driver&#39;s seat  19  when he operates the switching device  1 . For this purpose, capacitive coupling to the mobile ID transmitter  13  is also possible through electrode  18 . The security electrode  18  is connected, in turn, to the control unit  10 . Data from the capacitive signal is transmitted through capacitor  33  and the operator  30  to capacitor  34 . If the ID transmitter receives the signal from electrode  18 , it can send an additional release signal. It is also conceivable that the ID transmitter  13  only emits the identification signal to the control unit when it has received two different activation signals from electrode  5  and electrode  18 . The special arrangement of electrode  18  is not restricted to the driver&#39;s seat  19 . Instead, it is conceivable that this electrode  18  is also arranged in the steering wheel or a pedal, especially the brake pedal, or elsewhere, in order to be able to perform additional position monitoring of the operator  30 . As already mentioned previously, the security system  25  can also be used to secure additional electronic loads, such as a radiotelephone or navigation system, etc., in a vehicle, in order to prohibit other vehicle occupants, for example, children, from operating them. For this purpose, the system  25  can also contain several switching devices  1 . 
         [0036]      FIG. 2  shows a switching device  1  according to the invention, with an operating element  4  to be moved in a translatory manner. If an operator  30  now presses the operating element  4  with his finger, different switching positions (for example, switch positions  0  and I or  0 -III) can be operated. Each of these switching positions can be assigned a corresponding switching signal that is conveyed to the control unit  10 . Mechanical or electromechanical locking of the switching device  1  is not prescribed, regardless of whether the operator  30  can be identified or not by the correct mobile ID transmitter  13 . Only by checking/identification is a situation achieved in which the switching signal present, which is generated by the switching device  1 , is conveyed by the control unit  10  to the management system  12  or another load when the corresponding identification code is present from the ID transmitter. A simple design of the switching device  1  is thereby possible. The switching element  3 , operated by the operating element  4 , can consist of a switch, a raster, a key, a piezo element, etc. In a piezo element, it is conceivable, for example, that the operating pressure applied on the operating element  4  is measured, in order to distinguish the individual switching position  0  and I or  0 -III. For this purpose, the switching device  1  can have its own logic unit or logic component  8  arranged in the housing  2 . An additional sensor element can also be provided on the surface of the operating element  4  that serves to identify the fingerprint of an operator  30 . Corresponding evaluation of the measurement signal determined by the sensor element can also be implemented by the logic component  8 . 
         [0037]    For capacitive data transmission, a surface electrode  5  is provided, which is arranged on the inside of the operating element  4 . This electrode  5  can be glued, evaporated, welded on, or attached in some other way to the operating element  4 . In order for the operating element  4  to additionally contain a display element  7 , the capacitive electrode  5  has a recess, in which the display element  7  is arranged. This recess can consist of a hole. The described electrode is connected to control unit  10  by a direct or indirect connection. The switching device  1  can naturally be connected to the control unit by means of a plug. Optoelectronic coupling or connection  20  of the switching device  1  to the control unit  10  is then also conceivable. Another electrode  17  is additionally provided in the housing  2  of switching device  1  for an optional power-transmission unit  15 . This electrode is directly welded into the housing  2 . This electrode  17  can also be connected directly or indirectly to the control unit  10 . It is also conceivable that the electrode  17  also belongs to electrode  5  and is electrically connected to it. In this case, capacitive power transmission would then not be needed. A coil  16  is also optionally provided in  FIG. 2 , which can also send the required power to a currentless ID transmitter  13 . This coil  16  then also represents an element of the power-transmission unit  15 . Actual power transmission from switching device  1  to the mobile ID transmitter  13  preferably then occurs when the ID transmitter  13  is brought into the vicinity of switching device  1 . As already previously mentioned, the arrangement of electrode  17  represents an optional means for the coil  16  of the power-transmission unit  15 . In order to improve power transmission by the coil  16 , a recess in the capacitive electrode  5  can also be provided in the middle area, where the coil  16  is arranged on the back. It is also conceivable to arrange the coil  16  in front of electrode  5  on the operating element  4  and not behind electrode  5 , as shown. 
         [0038]    Another variant of the switching device  1  according to the invention is shown in  FIG. 3 . The switching element  3  in this variant is shown as a rotary switch with several switch positions (for example,  0  and I or  0 -III). The direction of rotation of the operating element  4  is indicated by arrow  4 ′. It is also conceivable that a translatory activation is possible with the rotational movement of the operating element  4 , in other words, the operating element  4  can additionally be pulled out or pushed into the switching device  1 , so that an additional switch position can be reached. This variant can therefore be used directly similar to an ordinary ignition-starter switch with a mechanical key. The electrode  5  necessary for capacitive data transmission is also provided in this case on the back or inside of the operating element  4 . The capacitive electrode  5  can consist of an electrically conducting film or layer or grid structure. This switching device  1  is also provided with a power transmission unit  15 , in order to be able to transmit power to a mobile ID transmitter  13  in an emergency. For this purpose, a coil  16  is introduced into the housing  2 , especially into a protrusion  6 . The protrusion  6  simultaneously serves as a stop for retaining the switching device  1  in a switch panel or a dashboard, etc. 
         [0039]    As can be seen from  FIG. 4 , the switching device  1  has a display element  7 , which can consist of a multicolored display, in order to display different switching states of the switching device  1  or functional states of the security system  25 . Several displays  7  can naturally also be arranged in the housing  2  or even the operating element  4 . It is also conceivable that acoustic signals, especially speech signals, can be issued by the display element  7 . 
         [0040]    Another example for the switching device  1  according to the invention is shown in  FIG. 5 . This switching device  1  is designed similar to the switching device  1  from  FIG. 2 , whereby a one-state switching element  3  with switching states  0  and I is provided. In this case, an operating element  4  is also used as a key or push element. The actual switching element  3 , which assigns a switching signal  0  or I to the corresponding operating state of the operating element  4 , is shown schematically. A total of two electrodes  5  and  17  are additionally provided on the inside of operating element  4 , electrode  5  being provided for capacitive data transmission and electrode  17  serving for power transmission to the mobile ID transmitter  13 . The annular electrode  17  then encloses the circular electrode  5 . It is also conceivable that the two electrodes  5 ,  17  are exchanged, so that no changes are produced to the method of function of the switching device  1 . In addition,  FIG. 5  shows schematically the individual plug contacts of plug  9 . The switching device  1  is preferably connected to the control unit  10  by a standard plug. Instead of an electrical connection  20 , an optical or optoelectronic connection  20  to the control unit  10  can also exist. Naturally, the connection  20  can also be achieved by an ordinary interface or an ordinary data-bus format. 
         [0041]    A top view of another variant of the switching device  1  according to the invention is shown in the last  FIG. 6 . This essentially shows the operating element  4  illuminated by a display element  7 . At least the inscriptions “ON” and “OFF” can be displayed on the operating element  4  by the display element  7 . For this purpose, the operating element  4  can consist of a transparent plastic. A film  23  with transparent areas  24  for the inscriptions can be arranged behind the operating element  4 , the inscriptions being illuminated from the rear by the display element  7 , in order to have the inscriptions appear. The display element  7  can consist of one or more light sources, such as LEDs, for this purpose. Different colors can also be emitted by the display element  7 . The above-mentioned film  23  is advantageously configured to be electrically conducting and is used as a large-area electrode  5 . It is also conceivable that the film  23  itself serves as a (color) display and emits light. In this case, the film  23  can serve as a surface electrode  5 . This electrically conducting film  23  can be connected electrically to another part of the surface electrode  5 , which is arranged, for example, on the housing  2  or the switching device  1 . 
         [0042]    Finally, it must be mentioned that the invention is not restricted to the variant shown of the switching device  1  or the security system  25 . All combinations of individual technical features are conceivable, as long as they do not explicitly exclude each other out. The practical examples shown of the switching device  1 , as well as the security system  25 , can also contain additional mechanical, electrical, and/or electronic components not shown.