JPH11324432A - Keyless entry device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely unlock a door even if a battery is dead. SOLUTION: The device is provided with an auxiliary power source 30 comprising a solar battery 30a and a capacitor 30b on a part of a vehicle. A portable transmitter 10 is provided with a light emission diode 14 for generating a trigger signal as light is made a medium, and an on-vehicle transmitter 10 is provided with a switching circuit 28. The switching circuit 28 connects the auxiliary power source 30 to a modulation circuit 22, a microcomputer 23, a drive circuit 24 and a demodulation circuit 25 on the basis of a trigger signal. Thereby the microcomputer 23, the drive circuit 24 and the demodulation circuit 25 operates as well as the case where they are power-supplied from a battery on the basis of power supply from the auxiliary power source 30.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a keyless entry device for a vehicle.

[0002]

2. Description of the Related Art In recent years, it has been desired to improve the security of vehicles. One of the means for improving the security is to eliminate the mechanical key of the door lock. If this mechanical key is abolished and a system that locks or unlocks the door electromagnetically is adopted, it is possible to prevent a person other than the driver of the vehicle from entering the vehicle interior.

One example of the above system is a keyless entry device. This keyless entry device includes a portable communication device, a vehicle communication device, and a door lock mechanism. The vehicle communication device generates a door lock signal or an unlock signal in response to communication with the portable communication device based on power supply from a battery. The door lock mechanism locks the door based on the door lock signal, and unlocks the door based on the unlock signal.

[0004]

However, if the mechanical key is abolished, when the battery is exhausted, the vehicle-mounted communication device is not supplied with power from the battery.
Unable to unlock door. Therefore, there is a problem that the driver cannot enter the vehicle interior.

On the other hand, as shown in Japanese Patent Application Laid-Open No. 8-189238, the portable communication device is provided with an auxiliary battery, and the portable communication device is electrically connected directly to a part of a vehicle. 2. Description of the Related Art There is an apparatus in which an in-vehicle communication device is operated by supplying power from an auxiliary battery of a portable communication device to the in-vehicle communication device. But,
When power is supplied from the portable communication device to the in-vehicle communication device, the portable communication device needs to be electrically connected directly to a part of the vehicle as described above, which is inconvenient.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and provides a keyless entry device for a vehicle in which a door is securely unlocked by utilizing a solar cell even when the battery is exhausted. With the goal.

[0007]

According to the first aspect of the present invention, a portable communication device (1) is provided.
0) and a signal generator for generating a door lock signal or an unlock signal in response to communication with a portable communication device based on power supply from a battery, which is a communication device mounted on the vehicle (hereinafter referred to as an in-vehicle communication device). Keyless entry device for a vehicle, comprising: an on-vehicle communication device (20) having (22 to 25) and a door lock mechanism (DA) for locking a door based on a door lock signal and unlocking the door based on an unlock signal. , An auxiliary power supply (30) for converting sunlight into electric power and storing the converted power is provided, and the portable communication device generates a trigger signal using electromagnetic waves as a medium.
5), and the in-vehicle communication device includes connection means (28) for connecting the auxiliary power supply to the signal generation means based on the trigger signal.

For this reason, even when the battery is dead,
The signal generating means operates in the same manner as when power is supplied from the battery based on power supply from the auxiliary power supply. Therefore, the signal generating means can surely unlock the door via the door lock mechanism. Thereby, the driver of the vehicle can enter the vehicle interior. Further, as in the invention according to claim 2, the trigger means is a light emitting element (14) and a switch means (15).
And the light emitting element may generate light based on the operation of the switch means and apply the light to the connection means as a trigger signal.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of a keyless entry device for a vehicle according to the present invention will be described below with reference to FIG. This keyless entry device is a card-type portable communication device 1
The portable communication device 10 includes a transmission / reception antenna 11, a modulation / demodulation circuit 12, and a control circuit 13.

The transmission / reception antenna 11 transmits a transmission signal using a radio wave as a medium based on the transmission signal from the modulation / demodulation circuit 12, and transmits a transmission antenna 21 of a vehicle-mounted communication device 20 described later.
It receives a transmission signal using the radio wave from the medium as a medium, generates a reception signal, and outputs it to the modulation / demodulation circuit 12. In addition, 2.45 GHz is adopted as the frequency of the two radio waves. The modulation / demodulation circuit 12 demodulates the received signal from the transmission / reception antenna 11, generates a processed received signal, and outputs the processed received signal to the control circuit 13. On the other hand, the modulation / demodulation circuit 12 modulates the control signal indicating the ID code of the vehicle from the control circuit 13 to transmit Is generated and output to the transmitting / receiving antenna 11.

The control circuit 13 receives the processed reception signal from the modulation / demodulation circuit 12 and outputs a control signal indicating a vehicle ID code to the modulation / demodulation circuit 12. The portable communication device 10 includes a light emitting diode 14 and a normally open switch 15. The light emitting diode 14 is supplied with power from the battery 16 when the switch 15 is turned on. As a result, the light emitting diode 14 generates a trigger signal using light as an example of an electromagnetic wave as a medium.

The reason for using an optical signal as the trigger signal is that the optical signal can reduce power consumption for amplifying the received signal in the receiving circuit, as compared with a radio frequency radio signal. The keyless entry device includes an in-vehicle communication device 20. The in-vehicle communication device 20 includes a transmission antenna 21. The transmission antenna 21 transmits a transmission signal using a radio wave as a medium based on a processing request signal from a modulation circuit 22 described later. As the transmitting antenna 21, a slot antenna formed on the outer wall of the door D directly below the handle DT of the door D is employed. Note that a patch antenna may be used as the transmission antenna 21 instead of the slot antenna.

As shown in FIG. 1, the on-vehicle communication device 20 includes a modulation circuit 22, a microcomputer 23, a driving circuit 24, and a demodulation circuit 25 on a circuit board K. The modulation circuit 22 modulates the request signal from the microcomputer 23 to generate the above processing request signal and outputs it to the transmission antenna 21. The microcomputer 23 executes a computer program according to the flowchart shown in FIG.

The power supply terminals of the microcomputer 23, the modulation circuit 22, the drive circuit 24 and the demodulation circuit 25 are connected to the positive terminal of the battery B through the switching circuit 28. The drive circuit 24 outputs a door lock signal or an unlock signal to the door lock mechanism DA under the control of the microcomputer 23. The door lock mechanism DA locks the door based on the door lock signal, and unlocks the door based on the unlock signal.

The demodulation circuit 25 includes a receiving antenna 26 described later.
And outputs a processed return signal to the microcomputer 23. This reply signal is the vehicle ID
This is a signal indicating a code. The reception antenna 26 receives the transmission signal using the radio wave from the transmission / reception antenna 11 of the portable communication device 10 as a medium, generates the return signal, and outputs it to the demodulation circuit 25. Note that the receiving antenna 26 is built in a room mirror of the vehicle.

The onboard communication device 20 has a light receiving circuit 27 and a switching circuit 28 on the circuit board K. Light receiving circuit 2
7 includes a photodiode 27a, and the photodiode 27a is a light emitting diode 14 of the portable device 10.
The power is supplied by an auxiliary power supply 30 described later in response to a trigger signal from the controller (see FIG. 3). Also, the photodiode 27
a is mounted directly below the left end of the handle DT of the door D as shown in FIG. This photodiode 27
The light receiving surface of a is exposed outside.

The photodiode 27a has its cathode terminal connected to the output terminal of the auxiliary power supply 30, and the anode terminal of the photodiode 27a is connected to the positive input terminal of the comparator CP of the signal processing circuit 27b. The signal processing circuit 27b includes resistance elements R1 to R3
It has. The resistance element R1 is a photodiode 27a.
Are connected in series to form a voltage dividing circuit. This voltage divider circuit
When the photodiode 27a is energized, a light receiving voltage is applied to the positive input terminal of the comparator CP from a common terminal of the photodiode 27a and the resistor terminal R1.

The resistor elements R2 and R3 are also connected in series to form a voltage dividing circuit. This voltage dividing circuit includes two resistance elements R2 and R3.
A reference voltage is applied to the negative input terminal of the comparator CP from the common terminal of the comparator CP. The comparator CP generates a high-level signal when the light receiving voltage is higher than the reference voltage.

As shown in FIG. 3, the switching circuit 28 includes a transistor TR1. The transistor TR1 is turned on in response to a high level signal from the light receiving circuit 27.
Note that the resistance element R4 is a pull-up resistor. Further, the switching circuit 28 includes a transistor TR2. The transistor TR2 is turned on when the transistor TR1 is turned on, and is turned off when the transistor TR1 is turned off. When the transistor TR2 is in the ON state, the auxiliary power supply 30 is supplied to the modulation circuit 22,
3. Connect to the drive circuit 24 and demodulation circuit 25.

The transistor TR2 has its base terminal connected to the collector terminal of the transistor TR1 through the resistance element R5. The diode D1 is a backflow prevention diode, and the resistor R6 is a bias resistor of the transistor TR2. Further, the switching circuit 28 includes a transistor TR3. Transistor TR3
Connects the battery B to the modulation circuit 22, the microcomputer 23, the drive circuit 24, and the demodulation circuit 25 in the ON state. On the other hand, the transistor TR3 is turned off when the transistor TR1 is turned on to cut off the modulation circuit 22, the microcomputer 23, the drive circuit 24, and the demodulation circuit 25 from the battery B.

The transistor TR3 is connected at its base terminal to a resistor R7 through a backflow prevention diode D2.
Connected to the ground. The diode D
Reference numeral 3 denotes a backflow prevention diode, and a resistance element R8 is a bias resistance of the transistor TR3. The auxiliary power supply 30 includes a solar cell 30a and a storage capacitor 30b. The solar cell 30a converts light energy of sunlight into electric energy and stores the electric energy in the capacitor 30b. As shown in FIG. 2, the solar cell 30a has a handle DT of the door D.
Is mounted on the outer wall of the door D via an electrical insulating film. Note that the handle DT of the door D is formed of a transparent resin material.

Hereinafter, the operation of the keyless entry device configured as described above will be described. The microcomputer 23 starts executing the computer program according to the flowchart of FIG. In step 100, the microcomputer 23
, A request signal is generated intermittently. Then, in step 101, it is determined whether or not the processing return signal from the demodulation circuit 25 has been input. Here, if there is an input of the process return signal, it is determined as YES, and in step 102, the ID code of the process return signal is read. Then, in step 103, the ID code of the processing return signal is compared with the ID code stored in the ROM of the microcomputer 23 in advance.

Here, if the ID code of the process return signal matches the ID code of the ROM, it is determined as YES, and a door unlock process is performed in step 104. As a result, the drive circuit 24 outputs an unlock signal to the door lock mechanism DA. Therefore, the door lock mechanism DA unlocks the door. If the door is not unlocked even though the operator carries the portable communication device 10 and approaches the vehicle, the driver determines that the battery B is dead and the light emitting diode of the portable communication device 10 The switch 15 is turned on by bringing the switch 14 close to the photodiode 27a. Then, the light emitting diode 14 of the portable communication device 10 generates a trigger signal.

Thus, the photodiode 27a becomes conductive upon receiving a trigger signal from the light emitting diode 14. Based on this conduction, the signal processing circuit 27b outputs a high-level signal to the switching circuit. As a result, the switching circuit 28 switches the auxiliary power supply 30 to the modulation circuit 22 and the microcomputer 2
3. Connect to the drive circuit 24 and demodulation circuit 25. In addition,
With this connection, the switching circuit 28 cuts off the modulation circuit 22, the microcomputer 23, the drive circuit 24, and the demodulation circuit 25 from the battery B.

For this purpose, the auxiliary power supply 30 supplies power to the microcomputer 23, the demodulation circuit 22, the drive circuit 24 and the modulation circuit 25 through the switching circuit 28. Therefore, the microcomputer 23 operates in the same manner as in the case where power is supplied from the battery B described above. As a result, the door is unlocked and the driver can enter the passenger compartment. If a process return signal is not input in step 101, NO is determined and the process of step 100 is performed. If it is determined in step 103 that the ID code indicated by the processing return signal does not match the ID code in the ROM, the determination is NO, and the processing in step 100 is performed.

Further, in the above-described embodiment, an example is described in which a signal using light as a medium is used as a trigger signal. However, the present invention is not limited to this, and a signal using low-frequency radio waves as a medium may be used. In this case, an electromagnetic coil is provided instead of the photodiode 27a of the vehicle-mounted communication device 20, and
An electromagnetic coil is provided instead of the light emitting diode 14 of the portable communication device 10.

Further, in the above embodiment, the solar cell 30
2, a description will be given of an example in which, as shown in FIG. 2, the rear side of the handle DT of the door D is mounted on the outer wall of the door D. However, the present invention is not limited to this, and the solar cell 30a may be mounted on the outer wall of the vehicle roof. Good. Note that, in the above embodiment, an example in which the capacitor 30b is used as a unit for storing electric energy from the solar cell 30a is described, but a secondary battery may be used instead of the capacitor 30b.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a vehicular keyless entry device according to the present invention.

FIG. 2 is a diagram showing an arrangement of a solar cell, a transmitting antenna, and a photodiode of FIG. 1;

FIG. 3 is an electric circuit diagram showing a light receiving circuit and a switching circuit of FIG.

FIG. 4 is a flowchart showing an operation of the microcomputer of FIG. 1;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Portable communication device, 14 ... Light emitting diode, 15 ... Switch, 20 ... In-vehicle communication device, 22 ... Modulation circuit, 23 ... Microcomputer, 24 ... Drive circuit, 25 ... Demodulation circuit,
28: switching circuit, 30a: solar cell, DA: door lock mechanism.

Continued on the front page (72) Inventor Mitsuru Otsuka 1-1-1, Showa-cho, Kariya-shi, Aichi Prefecture Inside Denso Co., Ltd. (72) Inventor Norito Furuta 14 Iwatani, Shimowasukamachi, Nishio-shi, Aichi Japan Auto Parts General Co., Ltd. Inside the research institute (72) Inventor Fumio Asakura 14 Iwatani, Shimowasumi-machi, Nishio-shi, Aichi Japan Inside the Japan Automotive Parts Research Institute

Claims (2)

[Claims] A portable communication device (10) and a communication device mounted on a vehicle (hereinafter referred to as an on-vehicle communication device), and a door lock signal in response to communication with the portable communication device based on power supply from a battery. Alternatively, an in-vehicle communication device (20) having signal generation means (22 to 25) for generating an unlock signal;
A keyless entry device for a vehicle, comprising: a door lock mechanism (DA) that locks the door based on the door lock signal and unlocks the door based on the unlock signal. A power source (30); the portable communication device includes trigger means (14, 15) for generating a trigger signal using electromagnetic waves as a medium; and the vehicle-mounted communication device switches the auxiliary power source based on the trigger signal. A keyless entry device for a vehicle, comprising a connection means (28) connected to the signal generation means. 2. The trigger means includes a light emitting element (14) and a switch means (15), wherein the light emitting element generates light based on an operation of the switch means, and applies the light to the connection means as the trigger signal. The keyless entry device for a vehicle according to claim 1, wherein: