Electronic key system

An electronic key system has a portable apparatus, an operation control device and an update control device. The portable apparatus selectively transmits a first signal and a second signal. The operation control device authorizes an operation of a key based on reception of the first signal. The update control device transmits an update signal in a private region of the owner of the portable apparatus. The portable apparatus has a counter and a portable apparatus controller. When receiving the update signal, the portable apparatus controller resets the counter. When the counting value of the counter is equal to or less than a predetermined limit value, the controller selects the first signal as a signal to be transmitted. When the counting value is in excess of the limit value, the controller selects the second signal as a signal to be transmitted.

BACKGROUND OF THE INVENTION

The present invention relates to an electronic key system for locking/unlocking a door of, for example, a vehicle or a house or for authorizing (allowing) starting of a vehicle engine.

Conventionally, a key using system such as a vehicle or house door locking device or an engine starter is provided with such an immobilizer function as to authorize locking/unlocking of the door or starting of the engine if an attempted communication is established between the key and the lock. In such a system, it is difficult to duplicate the key and also to unlock the door except by a regular key or start the engine, thus improving security.

By such a conventional system, however, if the regular key itself is stolen or lost, it may be used to illegally unlock the door or start the engine.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide an electronic key system which prevents a third party from using a stolen or lost key in an attempt of locking/unlocking or vehicle engine starting.

To achieve this object, the present invention provides an electronic key system. The electronic key system has a portable apparatus that is carried by an owner, an operation control device, security means and an update control device. The portable apparatus selectively wirelessly transmits a first signal and a second signal. An operation control device authorizes an operation of a predetermined operation object based on reception of the first signal transmitted by the portable apparatus. Security means operates based on reception of the second signal transmitted by the portable apparatus. The update control device wirelessly transmits an update signal in a private region of the owner of the portable apparatus. The portable apparatus has a counter and a portable apparatus controller. The counter counts time or a value that represents the number of times that the portable apparatus is used for controlling the operation control device. When receiving the update signal, the portable apparatus controller resets the counter. When the counting value of the counter is equal to or less than a predetermined limit value, the portable apparatus controller selects the first signal as a signal to be transmitted. When the counting value of the counter is in excess of the limit value, the portable apparatus controller selects the second signal as a signal to be transmitted.

The present invention also provides another electronic key system. The electronic key system has a portable apparatus that is carried by an owner, an operation control device, security means and an update control device. The portable apparatus wirelessly transmits an information signal including a portable apparatus information. The operation control device controls an operation of a predetermined operation object. The operation control device receives the information signal transmitted from the portable apparatus. The update control device wirelessly transmits a request signal in a private region of the owner of the portable apparatus. The portable apparatus wirelessly transmits a response signal based on reception of request signal. The update control device receives the response signal and the portable apparatus information that is included in the information signal from the operation control device. The update control device has a counter for counting time or a value that represents the number of times that the portable apparatus is used for controlling the operation control device. When receiving the request signal, the portable apparatus controller resets the counter. When receiving the portable apparatus information, the update control device commands the operation control device to authorize the operation of the operation object if the counting value of the counter is equal to or less than a predetermined limit value. The update control device causes the security means to perform security if the counting value of the counter is in excess of the limit value.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following will describe in detail a first embodiment implementing the present invention with reference toFIGS. 1 to 4.

As shown inFIGS. 1 and 2, an electronic key system1comprises a portable apparatus11which is carried by the owner (occupant of the house), an operation control device21, and an update control device31.

The portable apparatus11is provided with a reception circuit12, a transmission circuit13, a microcomputer14, a counter15, an operation switch16, and a display section17.

A reception antenna12aand a microcomputer14are connected to the reception circuit12. The reception circuit12, when having received through the reception antenna12aa variety of transmit signals sent from the operation control device21or the update control device31, demodulates these signals into a pulse signal and inputs it to the microcomputer14.

A transmission antenna13aand the microcomputer14are connected to the transmission circuit13. The transmission circuit13modulates an output signal of the microcomputer14into a radio wave having a predetermined frequency (300 MHz in the present embodiment) and transmits it to the outside via the transmission antenna13a.

The microcomputer14is specifically a control unit which is comprised of a CPU, a ROM, a RAM, which are not shown, and is provided also with a non-volatile memory14a.The memory14arecords therein a pre-set predetermined ID code and a predetermined use limit value (time value in the present embodiment).

When having received a registration preparation signal from the update control device31via the reception antenna12a,the microcomputer14automatically outputs to the transmission circuit13a predetermined registered ID code signal including an ID code. Furthermore, when having received a request signal from the operation control device21via the reception antenna12a,the microcomputer14automatically outputs a decision code comprised of an operation permitting code and a first ID code including the above-mentioned ID code, or the decision code comprised of an operation disabling code and a second ID code including the ID code.

The counter15, the operation switch16, and the display section17as reporting means are connected to the microcomputer14. The counter15counts time which has elapsed from a predetermined moment, based on an operation signal sent from the microcomputer14. The counter15is set to zero in an initial state. The counter15counts elapsed time in accordance with an adding method. The microcomputer14, when having received an update signal via the reception antenna12afrom the update control device31, performs update processing of putting a count value of the counter15into the initial state, that is, automatically updates it to zero. Furthermore, if a use limit value included in the update signal is different from that already recorded in the memory14a,the microcomputer14records the use limit value included in the update signal in the memory14ain the update processing. Upon completion of this update processing, the microcomputer14outputs an update completion signal to the transmission circuit13.

The operation switch16is comprised of a push button switch provided on a design face of the portable apparatus11. When the operation switch16is operated, the microcomputer14outputs a manual operation signal to the transmission circuit13.

The display section17is comprised of an LED provided on a visible part of the portable apparatus11. It is to be noted that the display section17may be comprised of a liquid crystal display. If the count value of the counter15is not more than a use limit value, the microcomputer14does not operate the display section17and, otherwise, operates it. That is, the microcomputer14indicates whether the count value of the counter15is in excess of a use limit value, in accordance with whether the display section17is operating or not.

The operation control device21, on the other hand, is provided on a door3of a house2as shown inFIG. 2. As shown inFIG. 1, the operation control device21includes a transmission circuit22, a reception circuit23, a microcomputer24, and a door lock drive device25. The operation control device21communicates with an update control device31, which will be discussed below, through a cable60.

A transmission antenna22ais connected to the transmission circuit22. The transmission circuit22converts the request signal output from the microcomputer24into a radio wave signal having a predetermined frequency (134 kHz in this case) and outputs it via the transmission antenna22ato a predetermined region around the door3. It is to be noted that as shown inFIG. 2the request signal in the present embodiment is output to a first region A1which is on the indoor and outdoor sides around the door3.

A reception antenna23ais connected to the reception circuit23. The reception circuit23receives via the reception antenna23athe ID code signal transmitted from the portable apparatus11. The reception circuit23demodulates this ID code signal into a pulse signal and also outputs it to the microcomputer24.

The microcomputer24is specifically a control unit which is comprised of a CPU, a ROM, and a RAM, which are not shown, and is provided with a non-volatile memory24a.The memory24arecords therein a pre-set predetermined ID code. The microcomputer24outputs the request signal to the transmission circuit22intermittently.

The door lock driver device25is electrically connected to the microcomputer24. The door lock driver device25is equipped with an actuator, not shown, which selectively locks/unlocks the door. The actuator is driven in accordance with a received electrical signal.

When the first or second ID code signal transmitted from the portable apparatus11in accordance with the request signal sent from the operation control device21has been received by the reception circuit23via the reception antenna23a,the microcomputer24compares an ID code included in either one of these two ID code signals to that recorded in the memory24a(ID code collation). Furthermore, the memory24ahas a predetermined decision code recorded therein. The microcomputer24compares a decision code included in either of these two ID code signals to that recorded in the memory24a(decision processing), to decide whether the decision code included in both ID code signals is an operation permitting code. As a result, if it decides that these ID codes agree with each other and that the decision code is the operation permitting code, the microcomputer24outputs an unlocking drive signal requesting unlocking to the door lock drive device25to cause it unlock the door. If it cannot receive none of these two ID code signals, on the other hand, the microcomputer24outputs a locking drive signal requesting locking to the door lock drive device25to cause it lock the door.

When an registration authorization signal transmitted from the update control device31has been received by the operation control device21through the cable60, the microcomputer24records an ID code included in this registration authorization signal in the memory24aand outputs a registration completion signal to the transmission circuit22.

As shown inFIG. 2, the update control device31is mounted inside the house2on a wall distant from the door3by a predetermined distance. As shown inFIG. 1, the update control device31includes a transmission circuit32, a reception circuit33, and a microcomputer34.

A transmission antenna32ais connected to the transmission circuit32. The transmission circuit32converts the registration preparation signal or the update signal output from the microcomputer34into a radio wave signal having a predetermined frequency (134 kHz in the present embodiment) and transmits this radio wave signal to a peripheral predetermined region via the transmission antenna32a.It is to be noted that as shown inFIG. 2in the present embodiment the registration preparation signal or the update signal is transmitted to a second region A2which is only on the indoor side of the house2in the periphery of the update control device31. That is, neither the registration preparation signal nor the update signal is transmitted to the outdoor side of the house2.

To the reception circuit33is connected a reception antenna33a.The reception circuit33receives via the reception antenna33athe ID code signal or the update completion signal transmitted from the portable apparatus11. The reception circuit33demodulates the ID code signal or the update completion signal into a pulse signal and also outputs it to the microcomputer34.

The microcomputer34is specifically a control unit which is comprised of a CPU, a ROM, and a RAM, which are not shown, and is provided with a non-volatile memory34a.The memory34arecords therein an ID code or a use limit value of the portable apparatus11. To the microcomputer34are connected a registration switch35, a setting switch36as setting means, and a buzzer37as reporting means. The microcomputer34is electrically connected with the microcomputer24of the operation control device21through an interface portion not shown. That is, as shown inFIGS. 1 and 2, the operation control device21and the update control device31are interconnected electrically.

The registration switch35is comprised of a push button switch. When the registration switch35is operated, the microcomputer34enters a registration mode. In the registration mode, the microcomputer34outputs the registration preparation signal to the transmission circuit32. When having received the registered ID code signal transmitted from the portable apparatus11in accordance with the registration preparation signal, the microcomputer34once records an ID code included in the registered ID code signal in the RAM etc. (temporary registration). The microcomputer34outputs to the transmission circuit32the update signal including a use limit value registered in the memory34a.When having received the update completion signal transmitted from the portable apparatus11in accordance with this update signal, the microcomputer34outputs to the operation control device21through the cable60the registration authorization signal including the above-mentioned ID code. When having received the registration completion signal transmitted from the operation control device21through the cable60in accordance with the registration authorization signal, the microcomputer34records in the memory34athe ID code which has been recorded in the above-mentioned RAM etc. and enters a normal mode.

In the normal mode, the microcomputer34intermittently outputs to the transmission circuit32the update signal including the use limit value which has been recorded in the memory34a.When having received the update completion signal transmitted from the portable apparatus11in accordance with the update signal, the microcomputer34outputs the operation signal to a buzzer37to operate it only for short time.

The setting switch36is comprised of a push button switch, a dial switch, and a sliding switch and capable of setting a use limit value. When the setting switch36is operated, the microcomputer34records in the memory34aa use limit value which has been set by this setting switch36.

Next, an operation aspect of the electronic key system1having the above-mentioned configuration is described referring to sequence charts shown inFIGS. 3 and 4.

<1> Procedure for Registering Portable Apparatus11

As shown in step S1ofFIG. 3, when the registration switch35is operated, the update control device31enters the registration mode, to transmit the registration preparation signal to the second region A2shown inFIG. 2as shown in step S2. When having received this registration preparation signal in the second region A2, the portable apparatus11transmits the ID code signal to the update control device31as shown in step S3.

When having received the registered ID code signal from the portable apparatus11, the update control device31once records in the RAM etc. the ID code included in the registered ID code signal as shown in step S4. Next, the update control device31transmits the update signal to the second region A2as shown in step S5. It is to be noted that the update signal includes the above-mentioned use limit value which has been set by the setting switch36.

When having received the update signal from the update control device31, the portable apparatus11records in the memory14athe use limit value included in the update signal and also operates the counter15as shown in step S6. The counter15starts counting time which has elapsed from a moment when the use limit value was set in the memory14a.Upon completion of processing of step S6, the portable apparatus11performs processing of step S7, that is, transmits the update completion signal to the update control device31.

When having received the update completion signal from the portable apparatus11, the update control device31transmits the registration authorization signal to the operation control device21through the cable60as shown in step S8. The operation control device21records in the memory24athe ID code of the portable apparatus11included in the registration authorization signal as shown in step S9. That is, in step S9, the operation control device21registers the ID code of the portable apparatus11. Upon completion of the registration processing, the operation control device21transmits the registration completion signal to the update control device31through the cable60as shown in step S10. Next, in step S11, when having received the registration completion signal from the operation control device21, the update control device31records in the memory34athe above-mentioned temporarily registered ID code.

By such registration processing, the ID code of the portable apparatus11is registered in the operation control device21and the update control device31, thus making it possible to carry out the subsequently described operations of locking/unlocking the door based on communication between the portable apparatus11and the operation control device21and of updating based on communication between the portable apparatus11and the update control device31.

<2> Locking/Unlocking and Update Operations

As shown in step S21ofFIG. 4, the operation control device21outputs the request signal to the first region A1shown inFIG. 2. If the portable apparatus11has entered the first region A1in a condition where the count value of the counter15is not more than a use limit value recorded in the memory14aas shown in step S22, the first ID code signal is transmitted from the portable apparatus11to the operation control device21as shown in step S23. That is, when having received the request signal in the condition where the count value of the counter15is not more than a use limit value, the portable apparatus11transmits this first ID code signal to the operation control device21.

When having received the first ID code signal, the operation control device21performs the above-mentioned ID code collation and decision processing. If it decides that the ID codes have agreed and also that the first ID code signal includes an operation permitting code, the operation control device21outputs the unlocking drive signal to the door lock drive device25to cause it to unlock the door.

Subsequently, as shown in step S25, the operation control device21outputs the request signal. For example, if the portable apparatus11cannot receive the request signal because it has moved out of the first region A1of the request signal, it stops transmitting the ID code signal as shown in step S26. Accordingly, the operation control device21outputs the locking drive signal to the door lock drive device25to cause it lock the door as shown in step S27.

Therefore, if the count value of the counter15of the portable apparatus11is not more than a use limit value, the owner of the portable apparatus11can automatically unlock the door3only by approaching it and can automatically lock it only by departing from it.

Furthermore, as shown in step S28, the update control device31transmits the update signal to the second region A2. For example, when having entered the second region A2and received this update signal, the portable apparatus11resets the count value of the counter15to zero and also transmits the update completion signal to the update control device31as shown in step S29. It is to be noted that if a use limit value included in this update signal is different from an existing use limit value already recorded in the memory14a,the portable apparatus11erases the existing use limit value and, instead, records the use limit value included in the update signal in the memory14a.That is, in this case, the portable apparatus11rewrites a use limit value to be recorded in the memory14a.The portable apparatus11transmits the above-mentioned update completion signal to the update control device31after it has completed such alteration of the use limit value.

When having received the update completion signal from the portable apparatus11, the update control device31outputs the operation signal to the buzzer37to operate it only for short time as shown in step S30.

There may be a case where even when the request signal has been output from the operation control device21as shown in step S31, this request signal is received by the portable apparatus11in a condition where the count value of the counter15is in excess of a use limit value recorded in the memory14aas shown in step S32. In this case, the portable apparatus11transmits the second ID code signal to the operation control device21as shown in step S33. Since the second ID code signal includes a operation disabling code as a decision code, the operation control device21inhibits unlocking of the door even when it has received the second ID code signal. That is, when having received the second ID code signal, the operation control device21inhibits locking/unlocking based on mutual communication between itself and the portable apparatus11even if the ID codes agree. The operation control device21functions as security means that operates based on reception of the second ID code signal transmitted by the portable apparatus11.

It is to be noted that when the operation switch16of the portable apparatus11has been operated, the portable apparatus11transmits a first manual operation signal including a manual locking/unlocking code, an ID code, and an operation permitting code if the count value of the counter15is not more than a use limit value. When having received the first manual operation signal, the operation control device21locks/unlocks the door based on the manual locking/unlocking code.

Furthermore, if this operation switch16has been operated in a condition where the count value of the counter15is in excess of a use limit value, the portable apparatus11transmits a second manual operation signal including a manual locking/unlocking code, an ID code, and a operation disabling code. When having received the second manual operation signal, the operation control device21inhibits locking/unlocking of the door. That is, if the count value of the counter15is in excess of a use limit value, the door is securely inhibited from being locked/unlocked by the portable apparatus11.

The present embodiment has the following advantages.

When having received the request signal from the operation control device21in a condition where the count value of the counter15is not more than a use limit value set in the memory14a,the portable apparatus11transmits the first ID code signal including an operation permitting code. Furthermore, when having received the request signal from the operation control device21in a condition where this count value is in excess of this use limit value, the portable apparatus11transmits the second ID code signal including a operation disabling code. When having received the first ID code signal, the operation control device21causes the door to be unlocked, while when having received the second ID code signal, on the other hand, it inhibits the door from being unlocked. Accordingly, this function makes the usable hours of the portable11finite, so that even if the portable apparatus11is stolen or lost, it is possible to prevent the door from being locked/unlocked using this portable apparatus11. Furthermore, when having received the update signal transmitted from the update control device31, the portable apparatus11updates the count value of the counter15into an initial state (resets to zero). Accordingly, the regular owner of the portable apparatus11can update the count value periodically to thereby continue door locking/unlocking operation by use of the portable apparatus11. In addition, such updating is carried out automatically, so that troublesome updating is not necessary, thus avoiding a degradation in operability of the portable apparatus11. Furthermore, the update signal is transmitted into the second region A2which only the regular owner of the portable apparatus11can enter, thus securely preventing updating from being carried out by any one other than this owner.

The use limit value can be altered using the setting switch36provided on the update control device31. If a use limit value included in the update signal, when it has been received by the portable apparatus11, is different from that already recorded in the memory14a,the portable apparatus11records this received use limit value in the memory14a.Based on this newly recorded use limit value, the portable apparatus11conducts control. Accordingly, if, for example, the owner cannot perform updating for a long time, he can set a large use limit value to thereby prevent the count value from exceeding the use limit value. Furthermore, the use limit value is altered by the update control device31provided in the house2. That is, the use limit value can be altered only by the regular owner of the portable apparatus11, not by a third party.

The portable apparatus11is capable of bi-directional communication with the update control device31, so that upon completion of control based on the update signal, it transmits a completion signal to the update control device31to notify it of the completion. When the completion signal has been received by the update control device31, its buzzer37operates. That is, the buzzer37operates when mutual communication has been completed between the portable apparatus11and the update control device31. Accordingly, the owner of the portable apparatus11can securely recognize normal completion of an update procedure.

The display section17of the portable apparatus11displays thereon whether the count value given by the counter15is not more than a use limit value or in excess of it. Accordingly, the owner of the portable apparatus11can securely recognize the state of the portable apparatus11. Furthermore, because such a report is made, the owner can make a third party as well know that the usability of the portable apparatus11is limited, thus diminishing the chance of the apparatus being stolen.

The following will describe a second embodiment implementing the present invention with reference toFIGS. 5 to 7. The present embodiment is mainly described on differences from the embodiment ofFIGS. 1 to 4, so that components common to these are only indicated by the same reference numerals and their description is omitted.

As shown inFIG. 5, in a portable apparatus11according to the present embodiment, the counter15and the display section17are omitted from that of the first embodiment. Furthermore, such a use limit value as mentioned above is not recorded in a memory14a.

A microcomputer14of the portable apparatus11receives via a reception antenna12aa response request signal transmitted from an update control device31. When having received the response request signal, the microcomputer14automatically outputs to a transmission circuit13a response signal including an ID code pre-set in the memory14a.

An update control device31is provided with a counter38and a display section39which are equivalent to the counter15and the display section17omitted from the portable apparatus11respectively. A memory34arecords therein such a use limit value as described above. More specifically, the memory34arecords therein a use limit value which is set by the above-mentioned setting switch36.

A microcomputer34of the update control device31intermittently outputs the response request signal to a transmission circuit32. Therefore, the transmission circuit32converts the response request signal into a radio wave signal having a predetermined frequency (134 kHz in the present embodiment) and transmits it to the second region A2shown inFIG. 2via a transmission antenna32a.When having received via a reception antenna33aand a reception circuit33the response signal transmitted from the portable apparatus11in accordance with the response request signal, the microcomputer34of the update control device31carries out update processing of automatically updating a count value of the counter15to an initial state (resetting the count value to zero).

When a use limit value is altered using the setting switch36, the microcomputer34rewrites a use limit value recorded in the memory34ato this altered value. Upon completion of such update processing, the microcomputer34outputs an operation signal to a buzzer37to cause it to report to that effect.

Next, an operation aspect of an electronic key system1having the above-mentioned configuration is described referring to sequence charts shown inFIGS. 6 and 7.

<1> Procedure for Registering the Portable Apparatus11

As shown in step S41ofFIG. 6, when a registration switch35is operated, the update control device31enters a registration mode, to transmit the registration preparing signal to the second region A2shown inFIG. 2as shown in step S42. When having entered the second region A2to receive this registration preparing signal, the portable apparatus11transmits an ID code signal to the update control device31as shown in step S43.

When having received the ID code signal, the update control device31once records (temporarily registers) in a RAM etc. an ID code included in this ID code signal as shown in step S44. Next, the update control device31transmits a registration authorization signal to the operation control device21through the cable60as shown in step S45. As shown in step S46, the operation control device21records in the memory24athe ID code included in the registration authorization signal. That is, in step S46, the operation control device21registers an ID code of the portable apparatus11. Upon completion of such registration processing, as shown in step S47, the operation control device21transmits a registration completion signal to the update control device31. As shown in step S48, when having received the registration completion signal, the update control device31records (permanently registers) the above-mentioned temporarily registered ID code in the memory34a.Next, as shown in step S49, the update control device31registers in the memory34aa use limit value set by the setting switch36and also operates the counter38. The counter38starts counting time which has elapsed from a moment when the use limit value was set in the memory34a.

Such registration processing provides a state where an ID code set in the portable apparatus11is registered in the operation control device21and the update control device31. It is thus possible to carry out the subsequently described operations of locking/unlocking the door based on communication between the portable apparatus11and the operation control device21and of updating based on communication between the portable apparatus11and the update control device31.

<2> Locking/Unlocking and Update Operations

As shown in step S51ofFIG. 7, the operation control device21outputs the request signal to the first region A1shown inFIG. 2. If, for example, the portable apparatus11has entered the first region A1to receive the request signal from the operation control device21, it automatically transmits the ID code signal to the operation control device21as shown in step S52.

When having received the ID code signal from the portable apparatus11, the operation control device21carries out the above-mentioned ID code collation in step S53, to transmit a portable apparatus information signal to the update control device31through the cable60on condition that the ID codes have agreed. More specifically, the microcomputer24of the operation control device21transmits the portable apparatus information signal to the microcomputer34of the update control device31via an interface portion not shown.

When having received the portable apparatus information signal from the operation control device21, the update control device31compares a count value of the counter38and a use limit value to each other. If the count value of the counter38is not more than the use limit value as shown in step S54, it transmits an unlocking authorization signal to the operation control device21through the cable60as shown in step S55.

When having received the unlocking authorization signal, the operation control device21outputs an unlocking drive signal to the door lock drive device25to cause it to unlock the door as shown in step S56.

As shown in step S57, the operation control device21continues to output the request signal. If, for example, the portable apparatus11goes out of the first region A1in which it can receive the request signal and so cannot receive the request signal as shown in step S58, it stops transmitting the ID code signal to the operation control device21. Therefore, the operation control device21outputs a locking drive signal to the door lock drive device25to cause it lock the door as shown in step S59.

Therefore, as far as the count value of the counter38of the update control device31is not more than a use limit value, the owner of the portable apparatus11only needs to approach the door3in order to automatically unlock it and only needs to depart from it in order to automatically lock it.

Furthermore, as shown in step S60, the update control device31transmits the response request signal to the second region A2intermittently. For example, when the portable apparatus11has entered the second region A2to receive this response request signal, it transmits the response signal to the update control device31as shown in step S61.

When having received the response signal from the portable apparatus11, the update control device31resets the count value of the counter38to zero and outputs the operation signal to the buzzer37to operate it only for a short time as shown in step S62.

On the other hand, there may be a case where the count value of the counter38is in excess of a use limit value even if the portable apparatus information signal has been transmitted to the update control device31through normal mutual communication between the portable apparatus11and the operation control device21as shown in steps S63to65. In this case, as shown in step S67, the update control device31transmits an unlocking inhibition signal to the operation control device21. As shown in step S68, when having received the unlocking inhibition signal, the operation control device21inhibits the door from being unlocked. That is, in the condition where the count value of the counter38in the update control device is in excess of a use limit value, the operation control device21inhibits unlocking operation by means of mutual communication between itself and this portable apparatus11.

The present embodiment has the following advantages.

The counter38of the update control device31counts time which has elapsed from a moment when the response signal transmitted from the portable apparatus11was received. If the count value of the counter38at a moment when the portable apparatus information was received from the operation control device21is not more than a use limit value, the update control device31transmits the unlocking authorization signal to the operation control device21. Furthermore, if this count value is in excess of the use limit value, the update control device31transmits the unlocking inhibition signal to the operation control device21. The operation control device21unlocks the door only when it has received the unlocking authorization signal. Thus, this function makes the usable hours of the portable apparatus11finite. Accordingly, if the portable apparatus11is stolen by a third party or lost, it is possible to prevent the door from being locked/unlocked using this portable apparatus11. Furthermore, when having received the response signal transmitted from the portable apparatus11, the update control device31updates the count value of the counter38to an initial state (resets to zero). Accordingly, the regular owner of the portable apparatus11can update the count value by periodically performing mutual communication between the portable apparatus11and the update control device31, thus continuing door locking/unlocking operation by use of the portable apparatus11. In addition, mutual communication between the portable apparatus11and the update control device31, that is, updating of the count value is automatically carried out only by permitting the portable apparatus11to approach the update control device31. Therefore, troublesome updating is not necessary, thus avoiding degradation in operability of the portable apparatus11. Furthermore, mutual communication between the portable apparatus11and the update control device31is carried out in the second region A2which only the regular owner of the portable apparatus11can enter, so that it is also possible to securely prevent updating from being carried out by any one other than this owner.

Since it is unnecessary to provide the portable apparatus11with the counter15and the display section17, it is possible to simplify the structure of the portable apparatus11, thus reducing the size and the costs of this portable apparatus11.

As shown inFIG. 8, the microcomputer24of the operation control device21may be omitted, and the transmission circuit22, the reception circuit23, and the door lock drive device25may be electrically connected to the microcomputer34of the update control device31via an interface portion not shown. In this configuration, the microcomputer34of the update control device31ofFIG. 8is caused to carry out the same processing as that performed by the microcomputer24of the operation control device21in each of the embodiments ofFIGS. 1 to 7. Even such a modified embodiment can obtain almost the same effects as those of each of the embodiments ofFIGS. 1 to 7and also simplify the structure of the operation control device21.

As shown inFIG. 9, a vehicle4may be provided with an operation control device41, and vehicle door locking/unlocking and engine starting authorization may be controlled based on wireless communication between the portable apparatus11and the operation control device41.

More specifically, the operation control device41comprises a transmission circuit42, a reception circuit43, and a microcomputer44which give almost the same functions as those of the above-mentioned operation control device21. The ID code signal has already been registered in the microcomputer44. The microcomputer44outputs the request signal to the transmission circuit42. The request signal is output via an antenna42aas a radio signal. The request signal is output to the periphery or inside of the vehicle4. When having received the request signal, the portable apparatus11transmits the above-mentioned ID code signal. When having received the ID code signal via the reception antenna43a,the reception circuit43of the operation control device41outputs this received signal to the microcomputer44. Furthermore, to the microcomputer44are connected a door lock drive device45and an engine starter46. The door lock drive device45is provided with an actuator, not shown, for locking/unlocking the door of the vehicle4. The door lock drive device45drives the actuator based on an electrical signal it has received. The engine starter46authorizes driving of a starter motor if it has received a starting authorization signal from the microcomputer44and, otherwise, inhibits it.

When having received the ID code signal transmitted from the portable apparatus11in accordance with the request signal, the microcomputer44carries out the above-mentioned ID code collation and decision processing. When the microcomputer44has received an ID code signal that corresponds to a request signal output to the periphery of the vehicle4and if collation of the relevant ID codes is approved and this ID code signal is judged to be the first ID code signal, it outputs the unlocking drive signal to the door lock drive device45to cause it to unlock the door. Furthermore, if it detects a mismatch in collation of the ID codes, the microcomputer44outputs the locking drive signal to the door lock drive device45to cause it to lock the door. If it decides that the received ID code signal is the second ID code signal, on the other hand, the microcomputer44inhibits the door from being unlocked.

When the microcomputer44has received an ID code signal that corresponds to a request signal output to the inside of the vehicle4and if it detects a match in collation of the relevant ID codes, on the other hand, it outputs the starting authorization signal to the engine starter46to put the engine into a state in which the engine can be started. Furthermore, if the microcomputer44detects a mismatch in collation of the ID codes, it stops outputting the starting authorization signal to the engine starter46, to put the engine into a state in which the engine cannot be started. In a case where the microcomputer44decides that the received ID code signal is the second ID code signal, on the other hand, it maintains the state in which the engine cannot be started.

In such a manner, it is possible both to control locking/unlocking of the door of the house2and to control locking/unlocking of the door of the vehicle4and starting of the engine, thus diminishing the chance of the vehicle4being stolen. It is to be noted that if the present embodiment is applied to the embodiment ofFIGS. 5 to 7, the update control device31ofFIG. 9is arranged in the vehicle so that the above-mentioned response request signal may be transmitted to the region which only the regular owner of the portable apparatus11can enter.

The embodiment ofFIG. 9may be modified by omitting the operation control device21and providing an electronic key system1that conducts control on at least one of the locking/unlocking of the door of the vehicle4and the starting of the engine. That is, the electronic key system1is comprised of the portable apparatus11, the update control device31, and the operation control device41.

In each of the embodiments ofFIGS. 1 to 9, the use limit value to be recorded in the memory14aor34amay be altered to a predetermined number of times of locking/unlocking the door. Then, the count value of the counter15or38may be altered to the number of times of locking/unlocking the door as counted from a moment when a use limit value was set in the memory14aor34a.This operation will make the usability of the portable apparatus11finite.

In the embodiment shown inFIGS. 1 to 4, the portable apparatus11may be provided with, in place of the display section17, a speaker or a buzzer that reports by sound or voice. Furthermore, the display section17may be omitted. It is to be noted that in such a case, the portable apparatus11preferably has such a design as to suggest that it has a “limited validity term”.

In each of the embodiments ofFIGS. 1 to 9, if the validity term of the portable apparatus11has expired, that is, its count value has exceeded its use limit value, the door is not locked/unlocked. The door, however, may be made locked/unlocked even with such a portable apparatus11that its validity term has expired. In such a case, an alarming function is provided to the buzzer37on the update control device31such that, for instance, the buzzer37emits loud alarm sound. That is, the buzzer37on the update control device31functions as the security means. By so doing, even if the door is unlocked illegally by a third party who has stolen the portable apparatus11and used it, the alarming sound is given, thus alarming the third party who has unlocked the door illegally. As a result, even if the third party has unlocked the door illegally by using the portable apparatus11, he must enter the house2while the alarming sound is being given, so that he is discouraged from doing so mentally. It is thus possible to inhibit illegal entry into the house2. Besides, for example, by operating the update control device31(for example, by entering a personal identification code) so that the operation of the buzzer37can be released, even if the alarming sound is given when an occupant of the house uses the portable apparatus11whose validity term has already expired, no serious problem will be caused.

In each of the embodiments ofFIGS. 1 to 9, an updated count value of the counter15or38may be reported by, for example, the display section17of the portable apparatus11.

Furthermore, such reporting of the updated count value may be omitted. By so doing, especially in the embodiment ofFIGS. 1 to 4, the update completion signal need not be transmitted from the portable apparatus11to the update control device31, thus making it possible to simplify the structure of a communication mechanism of the electronic key system1.

In each of the embodiments ofFIGS. 1 to 9, the counters15and38may each employ a subtraction system. In this case, the counters15and38each have an initial state as set to a use limit value so that they may count by subtracting from this use limit value. It is to be noted that if the present embodiment is applied to that ofFIGS. 1 to 4, the portable apparatus11transmits the second ID code signal when it has received the request signal from the operation control device21in a condition where the count value is zero. If the present embodiment is applied to that ofFIGS. 5 to 7, on the other hand, the update control device31transmits the unlocking inhibition signal when it has received the portable apparatus information signal in a condition where the count value is zero.

According to each of the embodiments ofFIGS. 1 to 9, the electronic key system1is provided with such a function that the owner of the portable apparatus11only needs to approach the door3in order to automatically unlock the door and only needs to leave it in order to automatically lock it, that is, a smart entry function. Such an electronic key system1, however, need not always be provided with the smart entry function. For example, the operation control device21may be intended only to authorize locking/unlocking of the door when mutual communication is established between itself and the portable apparatus11in a condition where the count value of the above-mentioned counters15or38is not more than a use limit value. That is, the electronic key system1may be provided with such a function that locking/unlocking by use of a mechanical key is possible only when this mutual communication is established, that is, the immobilizer function. Furthermore, the electronic key system1may be provided with such a function that the door is locked/unlocked only when the operation switch16of the portable apparatus11is operated, that is, a keyless entry function.

Each of the reception circuits12,23, and33and each of the transmission circuits13,22, and32in the portable apparatus11, the operation control device21, and the update control device31may be replaced by a short distance wireless communication module such as a Bluetooth one. In this case, however, only the regular owner of the portable apparatus11can enter a communication-possible region between the portable apparatus11and the update control device31.

In each of the embodiments ofFIGS. 1 to 9, wireless communication may be established between the microcomputer24of the operation control device21and the microcomputer34of the update control device31. It is to be noted that in this case, only the regular owner of the portable apparatus11can enter preferably this communication-possible region.

In each of the embodiments ofFIGS. 1 to 9, the operation control device21may be intended to lock/unlock not only a door but also a variety of fittings (including a gate door) such as a window or a sliding door.

In each of the embodiments ofFIGS. 1 to 9, the operation control device21may be arranged near the door3. Furthermore, the update control device31may be arranged in any region as far as only the regular owner of the portable apparatus11can enter it. Preferably, however, it is arranged where the owner visits frequently.

For example, the portable apparatus11may be connectable to a switched line device such as a cellular phone or a personal digital assistant (PDA), while the update control device31may be provided with a switched line portion that can communicate with that switched line device. In such a configuration, the above-mentioned updating operation can be carried out through communication between the update control device31and the portable apparatus11using such a switched line. In such a manner, an updating procedure can be carried out even if it is impossible to perform updating by bringing the portable apparatus11near the update control device31within a validity term. Furthermore, the operability of the electronic key system1can be improved further.

If no updating is carried out for a long period (for example, one week), an ID code of the portable apparatus11registered in the operation control device21and the update control device31may be deleted automatically.