JP2011109588A - Apparatus and method of setting antenna directivity for key radio receiver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an antenna directivity setting apparatus and method for a key radio receiver in which a performance of communication between an electronic key and a communication partner can be improved. <P>SOLUTION: When a radio wave is transmitted from an electronic key in an outer area (weak radio wave sensing area Ea1) than a normal receiving area Ea1 wherein communication is set up, the radio wave is delivered to a vehicle tuner 9 as a weak radio wave with which communication is not set up. When a weak wave is received by the vehicle tuner 9, antenna directivity of the vehicle tuner 9 is switched to another direction, and a receiving area is switched from the normal receiving area Ea1 to a comparative receiving area Eb. At such a time, if a reception strength of the received radio wave is changed to a higher value, communication is continued while maintaining the antenna directivity of the vehicle tuner 9 as it is. If the reception strength is not changed to a higher value, the antenna directivity of the vehicle tuner 9 is returned to the original normal direction and prepared for subsequent communication start. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to an antenna directivity setting apparatus and an antenna directivity setting method for a key radio wave receiver that sets the antenna directivity of a receiver mounted on a communication partner of an electronic key.

  As is well known in the art, as a vehicle key system, from the viewpoint of convenience and the like, an ID code as a key code is transmitted from an electronic key as a vehicle key to the vehicle by wireless communication, and the vehicle performs ID verification. Electronic key systems (see Patent Document 1) are widely used. In this kind of electronic key system, the electronic key is responded to the request from the vehicle, and the key operation-free system that causes the vehicle to automatically execute ID verification, or the vehicle-mounted device is operated by remote operation by the button operation with the electronic key. There is a wireless key system.

JP 2005-262915 A

  As shown in FIG. 11, the vehicle is provided with a vehicle tuner 81 that receives radio waves from the electronic key. This type of vehicle tuner 81 is formed so that the antenna directivity is circular. In practice, there is a current situation in which a null point 83 locally exists in the reception area 82 as shown in FIG. Therefore, if the electronic key is located at such a null point 83, the vehicle tuner 81 cannot receive radio waves from the electronic key and communication is not established. Therefore, some measures are taken to improve communication establishment. Was needed.

  An object of the present invention is to provide an antenna directivity setting device and an antenna directivity setting method for a key radio wave receiver capable of improving the communication performance between an electronic key and its communication counterpart.

  In order to solve the above problem, in the present invention, an antenna of a key radio wave receiver used in an electronic key system that causes the receiver to receive an identification ID transmitted from an electronic key and performs ID verification by the receiver. In the directivity setting device, a directivity switching component capable of switching the antenna directivity of the receiver and the receiver having the antenna directivity in one direction receive radio waves having a reception strength higher than at least a noise level. Determining means for determining whether or not there is a switching means for switching the antenna directivity of the receiver to the other direction complementing the reception null point generated in the one-way direction by the directivity switching component when the radio wave is received. Confirmation means for confirming whether or not the reception intensity of the radio wave after switching the antenna directivity is higher than a communicable reception level, and confirmation of the confirmation means Based on results, the gist that a directional setting means for setting the antenna directivity of the receiver in either the one orientation and other directions.

  According to this configuration, when a radio wave (weak radio wave) higher than the noise level is received by the receiver, the antenna directivity of the receiver is switched from one direction to the other direction, and the same radio wave is received in this other direction. To do. At this time, if the reception strength of the radio wave is increased, the electronic key enters the null point with the original directivity, and communication cannot be established. On the other hand, if the radio wave reception strength does not increase, the receiver assumes that communication is established with the original antenna directivity, restores the antenna directivity of the receiver, and waits for the start of subsequent communication. As a result, if the antenna directivity of the receiver is one-way, communication can be established even if the electronic key is located at the null point.

The gist of the present invention is that the directivity switching component comprises a capacitor capable of switching a resonance value of the receiver.
According to this configuration, since the directivity switching component is a capacitor, easily available parts can be used as the directivity switching component.

The gist of the present invention is that the receiver is composed of an inverted L antenna in which an L-shaped antenna element is attached to a substrate in the opposite direction.
According to this configuration, for example, when a directivity switching component is added to the tip of the inverted L antenna, the antenna directivity has a characteristic that changes drastically. Therefore, the antenna directivity for filling the null point can be effectively utilized by using this characteristic. It becomes possible to form more reliably.

  According to the present invention, in the antenna directivity setting method for a key radio wave receiver used in an electronic key system in which an identification ID transmitted from an electronic key is received by the receiver and ID verification is performed by the receiver. A directivity switching component capable of switching the antenna directivity is provided to the receiver with the antenna directivity turned in one direction, and it is determined whether or not a radio wave having a reception strength higher than the noise level is received. When the radio wave is received, the antenna directivity of the receiver is switched to the other direction complementing the reception null point generated in the one direction by the directivity switching component, and the radio wave is received after the antenna directivity is switched. It is confirmed whether the strength is higher than the communicable reception level, and based on the confirmation result, the antenna directivity of the receiver is set to the one direction or the other direction. And summarized in that the crab set.

  ADVANTAGE OF THE INVENTION According to this invention, the communication performance between an electronic key and its communicating party can be improved.

The block diagram which shows schematic structure of the electronic key system in one Embodiment. The block diagram which shows the specific structure of a vehicle tuner antenna directivity setting apparatus. The conceptual diagram which shows the range of a normal reception area and its weak radio wave detection area. The conceptual diagram which shows the range of a comparison reception area. The wave form diagram which shows the reception intensity change of the received electromagnetic wave in a vehicle tuner. The conceptual diagram which shows the state in which the electronic key is located in a normal receiving area. The conceptual diagram which shows the state which is not located in the null spot, although the electronic key is located in the weak radio wave detection area. The conceptual diagram which shows the state which is located in the null point while the electronic key is located in the weak radio wave detection area. The flowchart which shows execution operation of a vehicle tuner. The schematic diagram which shows the structure of the vehicle tuner in another example. The schematic diagram which shows the concept of the receiving area of the conventional vehicle tuner.

Hereinafter, an embodiment of an antenna directivity setting apparatus and an antenna directivity setting method for a key radio receiver embodying the present invention in an electronic key system for a vehicle will be described with reference to FIGS.
As shown in FIG. 1, the vehicle 1 is provided with a wireless key system 3 that switches between locking and unlocking the door lock by remote control using the electronic key 2. In this case, the electronic key 2 is provided with a communication control unit 4 that comprehensively manages the operation of the electronic key 2. In the communication control unit 4, an ID code (identification ID) is registered as a key-specific ID (Identification). The communication control unit 4 is connected to a UHF transmitter 5 that transmits radio waves in the UHF (Ultra High Frequency) band. The wireless key system 3 corresponds to an electronic key system.

  The electronic key 2 is provided with a locking button 6 that is operated when the door lock is locked, and an unlocking button 7 that is operated when the door lock is unlocked. Operations of these buttons 6 and 7 are managed by the communication control unit 4. When the communication control unit 4 detects that the locking button 6 or the unlocking button 7 has been operated, the communication control unit 4 transmits a wireless signal Swl corresponding to each button from the UHF transmitter 5. The wireless signal Swl includes an ID code and a function code. When the lock button 6 is operated, a lock request signal is transmitted, and when the lock button 7 is operated, an unlock request signal is transmitted. The wireless signal Swl corresponds to radio waves.

  Further, the vehicle 1 is provided with a collation ECU (Electronic Control Unit) 8 that collates the ID code of the electronic key 2. The ID code of the electronic key 2 that forms a pair with the vehicle 1 is registered in the verification ECU 8. In addition, a vehicle tuner 9 capable of receiving UHF band radio waves is connected to the verification ECU 8. A door lock device 10 that manages the locking and unlocking of the door lock is connected to the verification ECU 8 via an in-vehicle bus 11. The vehicle tuner 9 corresponds to a receiver.

  When the wireless signal Swl from the electronic key 2 is received by the vehicle tuner 9 and the wireless communication is established, the verification ECU 8 performs ID verification with the ID code in the wireless signal Swl. And if ID collation is materialized, a door lock will be locked / unlocked by the function code following it. That is, when the verification ECU 8 receives the lock request signal from the electronic key 2, if the ID verification is established, the verification ECU 8 causes the door lock device 10 to lock the door lock. On the other hand, when receiving the unlock request signal from the electronic key 2, the verification ECU 8 unlocks the door lock of the door lock device 10 if the ID verification is established.

  As shown in FIGS. 1 and 2, the vehicle 1 is provided with a vehicle tuner antenna directivity setting device 12 that can selectively switch the antenna directivity of the vehicle tuner 9. Incidentally, the antenna directivity of the vehicle tuner 9 may have a locally sharp null point 13 as shown in FIG. When the electronic key 2 is located at the null point 13, the vehicle tuner 9 cannot receive the radio wave of the electronic key 2 even though the electronic key 2 is located in the vicinity of the vehicle 1. Therefore, wireless communication is not established, and the door lock does not move even if the buttons 6 and 7 are pushed with the electronic key 2, which leads to a problem of feeling stress. The vehicle tuner antenna directivity setting device 12 corresponds to the antenna directivity setting device.

  By the way, as shown in FIG. 3, the vehicle tuner 9 cannot execute actual communication outside the reception area (normal reception area Ea1) where actual communication can be performed. There is a reception area (hereinafter referred to as a weak radio wave detection area Ea2 (dot area in FIG. 3)) that can be received while being weak. In the weak radio wave detection area Ea2, it is not possible to accurately grasp what the communication partner is, but it is understood that the radio wave of some reception frequency is being received. That is, it can be recognized that the electronic key 2 may be located in the vicinity of the vehicle 1.

  Therefore, in the case of the present example, when the vehicle tuner 9 assumes the antenna directivity in the normal direction (one direction), if the radio wave is received at a low reception intensity (weak level) that cannot be communicated, the electronic key 2 approaches the vehicle 1. It is considered to be. At this time, as shown in FIG. 4, the antenna directivity of the vehicle tuner 9 is switched from the normal direction to the other direction so that the reception area in the same direction (hereinafter referred to as a comparative reception area Eb) is the vehicle. 1 around. This comparison reception area Eb is an area that complements the null point 13 that occurs in the normal reception area Ea1, and is located in a difference area from the normal reception area Ea1 (shaded area in FIG. 4; hereinafter referred to as a compensation area Ek). This is for ensuring establishment of communication with the electronic key 2 to be performed. Then, the reception intensity Vx of the radio wave when the vehicle tuner 9 takes the comparative reception area Eb is obtained. If the reception intensity Vx increases, the reception is continued, and if the reception intensity Vx does not increase, the antenna of the vehicle tuner 9 is obtained. The directivity is returned to the original normal direction, and the antenna directivity of the vehicle tuner 9 is set.

  As shown in FIG. 2, the vehicle tuner 9 is an inverted L antenna in which the antenna element 14 has an inverted L shape. The antenna element 14 is attached to a substrate 15 on which electronic components of the vehicle tuner 9 are mounted. A capacitor 16 is connected to the antenna element 14 via a switch 17 as an antenna directivity switching element of the vehicle tuner 9. The capacitor 16 is for shifting the resonance value of the vehicle tuner 9, and switches the antenna directivity of the vehicle tuner 9 without changing the reception power of the vehicle tuner 9 depending on whether it is connected to the antenna element 14 or not. Is possible. The capacitor 16 constitutes a directivity switching component, and the switch 17 constitutes a switching means.

  Here, if the capacitor 16 is not added to the antenna element 14, the reception area of the vehicle tuner 9 is the normal reception area Ea1. Further, when the capacitor 16 is added to the antenna element 14, the reception area of the vehicle tuner 9 changes greatly and takes the comparative reception area Eb. The comparative reception area Eb is formed as a reception area that complements, ie covers, the null point 13 that occurs in the area Ea1 when the vehicle tuner 9 takes the normal reception area Ea1. The null point 13 corresponds to a place where it is difficult for radio waves that are sharply cut toward the vehicle 1 to reach the circle when the reception area that the normal reception area Ea1 should take is a circle.

  By the way, as shown in FIG. 5, the reception intensity Vx (reception level) of the vehicle tuner 9 takes a high value if radio waves can be received nearby, and when the value exceeds a threshold value Vth0, the data of the received radio waves are read and wireless communication is performed. (ID verification) is possible, but even if the received radio wave does not exceed the threshold value Vth0, if a value higher than the noise level (Vnoise) is taken, communication cannot be executed, but some weak radio wave is received. Judgment is possible. That is, a radio wave having a reception intensity between Vth0 and Vnoise can be detected as a weak radio wave.

  Therefore, as shown in FIGS. 1 and 2, the collation ECU 8 determines whether or not the vehicle tuner 9 has received a weak radio wave higher than the noise level Vnoise when the vehicle tuner 9 takes the normal reception area Ea1. A weak radio wave detection unit 18 for viewing is provided. The weak radio wave detection unit 18 of this example determines whether or not the weak radio wave is received, that is, whether or not the electronic key 2 is located in the weak radio wave detection area Ea2 by checking the presence or absence of the weak radio wave. The weak radio wave detection unit 18 corresponds to a determination unit, and the threshold value Vth0 corresponds to a communication reception level.

  The verification ECU 8 is provided with a directivity switching unit 19 that switches the antenna directivity of the vehicle tuner 9 to the other direction when a weak radio wave is received by the vehicle tuner 9. The directivity switching unit 19 turns on the switch 17 to connect the capacitor 16 to the antenna element 14 to switch the antenna directivity of the vehicle tuner 9 to the other direction, and this time, the same radio wave is received in the comparison reception area Eb. The directivity switching unit 19 constitutes switching means.

  The verification ECU 8 is provided with a reception strength confirmation unit 20 for confirming whether or not the reception strength Vx of the received radio wave when the antenna directivity of the vehicle tuner 9 is switched to the other direction is higher than the threshold value Vth0. . At this time, if the reception intensity Vx is switched to a high value, it can be seen that the electronic key 2 is located in the comparison reception area Eb, and if the radio wave reception is performed in the area Eb, the null point 13 can be complemented. On the other hand, if the reception strength Vx is not switched to a high value, it can be seen that it is better to perform reception in the normal reception area Ea1 before the directivity switching because the electronic key 2 is not at the null point 13. The reception strength confirmation unit 20 corresponds to confirmation means.

  The verification ECU 8 is provided with a directivity setting unit 21 that sets the antenna directivity of the vehicle tuner 9 based on the confirmation result of the reception strength confirmation unit 20. The directivity setting unit 21 continues to turn on the switch 17 to change the antenna directivity of the vehicle tuner 9 when the reception intensity Vx when the antenna directivity of the vehicle tuner 9 is switched to the other direction becomes higher than the threshold value Vth0. Leave it in the other direction. On the other hand, if the reception intensity Vx when the antenna directivity of the vehicle tuner 9 is switched to the other direction is equal to or lower than the threshold value Vth0, the directivity setting unit 21 returns the switch 17 to turn off the antenna directivity of the vehicle tuner 9. Return to normal orientation. The directivity setting unit 21 corresponds to directivity setting means.

Next, the operation of the vehicle tuner antenna directivity setting device 12 of this example will be described with reference to FIGS.
First, as shown in FIG. 6, it is assumed that the lock button 6 (unlock button 7) is operated with the electronic key 2 when the electronic key 2 is located in the normal reception area Ea1. It is assumed that the vehicle tuner 9 initially has a normal antenna directivity. At this time, since the radio wave from the electronic key 2 reaches the vehicle tuner 9 at a value higher than the threshold value Vth0, communication between these two parties is established. Therefore, the weak radio wave detection unit 18 does not take a state of detecting the weak radio wave and does not operate. As a result, the antenna directivity of the vehicle tuner 9 is set to the normal direction, and the subsequent communication is continued.

  Subsequently, as shown in FIG. 7, it is assumed that the lock button 6 (unlock button 7) is operated with the electronic key 2 when the electronic key 2 is located in the weak radio wave detection area Ea2 other than the compensation region Ek. At this time, the radio wave from the electronic key 2 reaches the vehicle tuner 9 at a value higher than the noise level Vnoise but lower than the threshold value Vth0. Therefore, the weak radio wave detection unit 18 recognizes that Vx> Vnoise is established, and recognizes that the electronic key 2 may be approaching the vehicle 1.

  At this time, the directivity switching unit 19 immediately turns on the switch 17 and adds the capacitor 16 to the antenna element 14 to switch the antenna directivity of the vehicle tuner 9 from the normal direction to the other direction. When the vehicle tuner 9 is switched to the other direction, the reception area of the vehicle tuner 9 is switched to the comparison reception area Eb. Then, the vehicle tuner 9 receives the radio wave received when the antenna directivity is in the normal direction by switching to the other direction. The reception strength confirmation unit 20 confirms whether or not the reception strength Vx of the received radio wave when the antenna directivity of the vehicle tuner 9 is switched to the other direction is higher than the threshold value Vth0.

  Here, since it is assumed that the electronic key 2 is located in the weak radio wave detection area Ea2 other than the compensation area Ek, the electronic key 2 is compared when the reception area of the vehicle tuner 9 is switched to the comparison reception area Eb. A state where it is not located in the reception area Eb is taken. For this reason, the radio wave received by the vehicle tuner 9 does not switch to a high value even if the antenna directivity of the vehicle tuner 9 is switched to another direction, and remains a value lower than the threshold value Vth0. That is, even if the antenna directivity of the vehicle tuner 9 is switched from the normal direction to the other direction, wireless communication between the vehicle 1 and the electronic key 2 is not established.

  Therefore, even when the antenna directivity of the vehicle tuner 9 is switched from the normal direction to the other direction when the electronic key 2 is located in the weak radio wave detection area Ea2 other than the compensation region Ek, the reception intensity confirmation unit 20 results in Vx> Recognize that Vth0 is not satisfied. When confirming that Vx> Vth0 is not established, the directivity setting unit 21 returns the antenna directivity of the vehicle tuner 9 to the original normal direction, and sets the antenna directivity of the vehicle tuner 9 to the same direction. Therefore, the vehicle tuner 9 recognizes that the electronic key 2 is approaching the vehicle 1 and recognizes that the electronic key 2 is about to enter the normal reception area Ea1.

  Next, as shown in FIG. 8, it is assumed that the lock button 6 (unlock button 7) is operated with the electronic key 2 when the electronic key 2 is positioned in the compensation region Ek. Since the compensation area Ek is a part of the weak radio wave detection area Ea2, the radio wave from the electronic key 2 reaches the vehicle tuner 9 at a value lower than the threshold value Vth0. Therefore, the weak radio wave detection unit 18 detects reception of the weak radio wave and recognizes that the electronic key 2 may be approaching the vehicle 1.

  At this time, the directivity switching unit 19 immediately turns on the switch 17 to add the capacitor 16 to the antenna element 14 and switches the antenna directivity of the vehicle tuner 9 to the other direction, as in the example of FIG. The reception area of the tuner 9 is set as a comparison reception area Eb. Then, the vehicle tuner 9 receives the radio wave received when the antenna directivity is in the normal direction by switching to the other direction.

  Here, since the case where the electronic key 2 is located in the compensation area Ek is assumed, when the reception area of the vehicle tuner 9 is switched to the comparison reception area Eb, the electronic key 2 is located in the comparison reception area Eb. Take a state. For this reason, the radio wave received by the vehicle tuner 9 switches to a high value, and as a result, changes to a value higher than the threshold value Vth0. That is, when the antenna directivity of the vehicle tuner 9 is switched from the normal direction to the other direction, wireless communication between the vehicle 1 and the electronic key 2 is established.

  Therefore, when the electronic key 2 is located in the compensation region Ek, the reception strength confirmation unit 20 recognizes that Vx> Vth0 is established as a result of switching the antenna directivity of the vehicle tuner 9 from the normal direction to the other direction. . When confirming that Vx> Vth0 is established, the directivity setting unit 21 keeps the antenna directivity of the vehicle tuner 9 in the other direction, and continues wireless communication in this state. Thereby, even if the electronic key 2 is located at the null point 13, the radio wave from the electronic key 2 reaches the vehicle tuner 9, so that the door lock operation with the electronic key 2 can be executed without any problem. It becomes.

  Next, the execution operation of the vehicle tuner 9 will be described according to the flowchart of FIG. Note that the flowchart of FIG. 5 is repeatedly executed when the vehicle tuner 9 is in a power-on state.

  In step 100, it is determined whether or not the reception intensity Vx of the radio wave received by the vehicle tuner 9 exceeds the threshold value Vth0. That is, it is determined whether or not the electronic key 2 is located in the weak radio wave detection area Ea2. The threshold value Vth0 is a reference value for checking whether or not the electronic key 2 is located in the weak radio wave detection area Ea2, and corresponds to the threshold value shown in FIG. Here, if Vx> Vth0 is established, it is determined that the radio wave reception level is sufficient, and the process proceeds to step 101. If Vx> Vth0 is not satisfied, the process proceeds to step 102.

In step 101, a radio wave receiving operation is executed. That is, radio wave reception is executed in a state where the capacitor 16 is not added, that is, in a normal antenna directivity.
In step 102, it is determined whether or not the reception intensity Vx exceeds the noise level Vnoise. Here, if Vx> Vnoise is established, the process proceeds to step 103. On the other hand, if Vx> Vnoise is not established, radio wave reception is added, so the process proceeds to return and the flow ends.

  In step 103, the switch 17 in the off state is turned on, and the capacitor 16 is added to the vehicle tuner 9. As a result, the antenna directivity of the vehicle tuner 9 is switched from the normal direction to the other direction, and a comparative reception area Eb is formed around the vehicle.

  In step 104, it is determined whether or not the reception intensity Vx is higher than the threshold value Vth0. At this time, if the reception intensity Vx is higher than the threshold value Vth0, it can be seen that the antenna directivity of the vehicle tuner 9 is preferably in the other direction than in the normal direction. Therefore, if Vx> Vth0 is satisfied, the process proceeds to step 105, and if Vx> Vth0 is not satisfied, the process proceeds to step 106.

In step 105, a radio wave receiving operation is executed. That is, it is tried whether radio waves can be received with the capacitor 16 added, that is, with antenna directivity in the other direction.
In step 106, the switch 17 switched to the on state is turned off, and the capacitor 16 of the vehicle tuner 9 is turned off. That is, the vehicle tuner 9 is operated only by the antenna element 14 to return the antenna directivity of the vehicle tuner 9 to the original normal position. As a result, a normal reception area Ea1 is formed around the vehicle as a reception area of the vehicle tuner 9, and the start of communication in the area Ea1 is awaited.

  Therefore, in this example, when a weak radio wave is received by the vehicle tuner 9 with the antenna directivity set to the normal direction, the antenna directivity of the vehicle tuner 9 is switched from the normal direction to the other direction. Then, the position of the electronic key 2 is determined by checking whether the reception intensity Vx after the directivity switching is higher than the threshold value Vth0. At this time, if the reception strength Vx does not become higher than the threshold value Vth0, the antenna directivity of the vehicle tuner 9 is returned to the original normal direction, and the next wireless communication is started, and the reception strength Vx is higher than the threshold value Vth0. If so, the wireless communication is continued with the antenna directivity of the vehicle tuner 9 remaining in the other direction.

  For this reason, even if the electronic key 2 is located at the null point 13, the radio wave transmitted from the electronic key 2 at this time can be received by the vehicle tuner 9 with the antenna directivity switched to the other direction. Become. Therefore, even if the electronic key 2 is located at the null point 13, the radio wave from the electronic key 2 can be delivered to the vehicle tuner 9, so that wireless communication can be established even under this situation. It becomes possible. For this reason, it becomes possible to make the establishment of communication of wireless communication high.

According to the configuration of the present embodiment, the following effects can be obtained.
(1) When the antenna directivity of the vehicle tuner 9 is in the normal direction, even if the electronic key 2 is located at the null point 13 of the same directivity, by using the communication sequence of this example, Can be received by the vehicle tuner 9. Therefore, since the communication failure condition at the null point 13 is eliminated, the communication possibility of wireless communication can be improved.

  (2) Since the capacitor 16 is used as a component for switching the antenna directivity of the vehicle tuner 9, the antenna directivity of the vehicle tuner 9 can be switched by an easily available inexpensive component such as the capacitor 16.

  (3) When the capacitor 16 is added to the tip of the inverted L antenna, the antenna directivity is drastically changed. In this example, since the antenna directivity of the vehicle tuner 9 is switched using this characteristic, the comparative reception area Eb that fills the null point 13 can be efficiently created.

Note that the embodiment is not limited to the configuration described so far, and may be modified as follows.
The element that changes the antenna directivity of the vehicle tuner 9 is not limited to the capacitor 16. For example, as shown in FIG. 10, anything may be used as long as it can change the antenna directivity of reception like a metal plate 51 or the like.

  When switching the antenna directivity of the vehicle tuner 9 from the normal direction to the other direction, it is not limited to switching the direction by turning on the switch 17 that normally takes the off state. For example, the switch 17 is normally in the on state, and the antenna directivity of the vehicle tuner 9 may be switched from the normal direction to the other direction by switching the switch 17 in the on state to off.

The comparison reception area Eb may take any area shape as long as the null point 13 can be complemented (covered).
The vehicle tuner 9 is not limited to an inverted L antenna, and may be another antenna such as a dipole antenna or a slot antenna.

The frequency of the wireless key system 3 is not limited to UHF, and other bands may be used.
The vehicle tuner antenna directivity setting device 12 is not limited to a configuration using the wireless key system 3. For example, a system independent of the wireless key system 3 may be used.

  The vehicle tuner antenna directivity setting device 12 is not limited to being applied to the wireless key system 3, and may be applied to, for example, a key operation free system. The key operation free system is a system that automatically transmits a key ID reply request from the vehicle, and performs ID verification using the ID code returned from the electronic key in response to the request.

  The vehicle tuner antenna directivity setting device 12 is not limited to being mounted only on the vehicle 1, but may be installed anywhere as long as it is a device, device, or system that performs wireless key verification.

Next, technical ideas that can be grasped from the above-described embodiment and other examples will be described below together with their effects.
(A) In any one of claims 1 to 3, the electronic key is provided with an operation unit that operates when operating the operation target on which the receiver is installed, and when the operation unit is operated, A transmission signal including the identification ID of the electronic key and a function code corresponding to the operation means is transmitted, and the antenna directivity of the vehicle tuner is set based on the transmission signal. According to this configuration, it is possible to set the antenna directivity of the vehicle tuner using the transmission signal from the electronic key.

  2 ... an electronic key, 3 ... a wireless key system as an electronic key system, 9 ... a vehicle tuner as a receiver, 12 ... a vehicle tuner antenna directivity setting device as an antenna directivity setting device, 13 ... a null point, 14 ... an antenna Element 15, substrate, 16, capacitor constituting directivity switching component, 17, switch constituting switching means, 18, weak radio wave detection section as determination means, 19, directivity switching section constituting switching means, 20 ... reception intensity confirmation unit as confirmation means, 21 ... directivity setting section as directivity setting means, 51 ... metal plate constituting directivity switching component, Swl ... wireless signal as radio wave, Vx ... reception intensity, Vth0 ... Threshold, Vnoise ... Noise level.

Claims (4)

In an antenna directivity setting device for a key radio wave receiver used in an electronic key system that receives an identification ID transmitted from an electronic key,
A directivity switching component capable of switching the antenna directivity of the receiver;
In the receiver in which the antenna directivity is one-way, determination means for determining whether or not a radio wave having a reception intensity higher than a noise level is received,
When the radio wave is received, switching means for switching the antenna directivity of the receiver by the directivity switching component to the other direction complementing the reception null point generated in the one direction,
Confirmation means for confirming whether or not the reception intensity of the radio wave after switching the antenna directivity is higher than a communicable reception level;
The antenna directivity of the key radio wave receiver, comprising: directivity setting means for setting the antenna directivity of the receiver to one of the one direction and the other direction based on the confirmation result of the confirmation means Sex setting device. 2. The antenna directivity setting apparatus for a key radio wave receiver according to claim 1, wherein the directivity switching component comprises a capacitor capable of switching a resonance value of the receiver. The antenna directivity setting of the key radio wave receiver according to claim 1 or 2, wherein the receiver is configured by an inverted L antenna attached to a substrate with an L-shaped antenna element facing in an opposite direction. apparatus. In an antenna directivity setting method for a key radio receiver used in an electronic key system that receives an identification ID transmitted from an electronic key,
The receiver is provided with a directivity switching component capable of switching its antenna directivity, and whether or not a radio wave having a reception strength higher than at least a noise level is received by the receiver having a single antenna directivity. When the radio wave is received, the antenna directivity of the receiver is switched to the other direction complementing the reception null point generated in the one direction by the directivity switching component, and the antenna directivity after switching Confirm whether the reception intensity of the radio wave is higher than the communicable reception level, and based on the confirmation result, set the antenna directivity of the receiver to the one direction or the other direction. An antenna directivity setting method for a key radio wave receiver.

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