Electrical transmission or interconnection systems – Vehicle mounted systems – Automobile
Reexamination Certificate
1999-07-01
2001-08-28
Paladini, Albert W. (Department: 2736)
Electrical transmission or interconnection systems
Vehicle mounted systems
Automobile
C180S287000, C340S539230, C340S870030
Reexamination Certificate
active
06281599
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a remote control apparatus which effects changeover between different operation states of equipment, such as locked and unlocked states of a vehicle door, when a user carrying a portable unit approaches to or moves away from the door.
BACKGROUND OF THE INVENTION
A remote control apparatus of the above-described type suitable for locking and unlocking a vehicle door is called a keyless entry system or a smart entry system. For example, Japanese Patent Application Laid-Open No. 5-106376 discloses a system comprising a portable radio unit and a vehicle-mounted radio unit. The portable radio unit includes first transmission means which transmits a reply signal or response signal when first reception means receives a transmission request signal or call signal. The vehicle-mounted radio unit includes second transmission means for transmitting the call signal at predetermined intervals, and control means which outputs a signal for unlocking doors of a vehicle when second reception means receives the response signal and outputs a signal for locking doors of a vehicle after passage of a predetermined period of time during which the response signal is not received. When a driver carrying the portable radio unit approaches to the vehicle in order to enter the vehicle, the driver-side door is automatically unlocked, and when the driver exits and moves away from the vehicle, the door is automatically locked.
When the driver is outside the vehicle, the second transmission means transmits the call signal. That is, the call signal is transmitted when the engine of the vehicle is stopped. Accordingly, the transmission of the call signal imposes a load on a power source (battery) onboard the vehicle, so that battery electrical power is consumed. If the transmission interval of the call signal is increased in order to reduce power consumption and the communicable distance is relatively short, there arises a problem that the driver carrying the portable radio unit reaches the driver-side door from an incommunicable position during a period between transmission of a call signal and transmission of a next call signal, with the result that the door is not opened even though the driver attempts to open the door. This problem can be mitigated if the transmission power of the call signal is increased in order to increase the communicable distance. In this case, since the amount of consumed power per transmission of the call signal increases, this method is not suitable for reduction of battery power consumption. Accordingly, the transmission interval of the call signal cannot be simply increased.
SUMMARY OF THE INVENTION
A first object of the present invention is to provide a remote control apparatus which can reduce power consumption resulting from repeated transmission of a transmission request signal.
In accordance with the invention, a controller outputs a transmission request signal to a portable unit via an object sensor. The object sensor outputs to the controller a signal indicting whether or not an object, such as a human hand, is present. The controller reduces the transmission power of the transmission request signal when the object sensor senses no object and a receiver receives a reply signal which is transmitted by the portable unit in response to the transmission request signal. The controller unlocks a door after reception of a predetermined ID code from the portable unit and when the object sensor detects the presence of the object. Since the transmission power of the transmission request signal is reduced when the receiver receives a reply signal, electrical power required for transmission can be reduced. The door is unlocked when the portable unit that transmits a reply signal representing the predetermined identification code approaches the receiver, and the sensor senses the human hand. Thus, a person carrying the portable unit can open the door.
Preferably, the controller transmits the transmission request signal with high transmission power at predetermined interval t
1
when the receiver receives no reply signal, stops transmission of the transmission request signal when the receiver receives a reply signal, subsequently waits up to a predetermined period t
2
until the object sensor detects an object, and transmits the transmission request signal with low transmission power at predetermined intervals t
4
when a predetermined period t
2
has elapsed during which the object sensor senses no object. Therefore, electrical power required for transmission can be conserved. When the object sensor does not sense an object even after the predetermined period t
2
has elapsed, the controller resumes transmission of the transmission request signal. However, since the transmission power is low, the power consumption is low. Although the transmission power is low, communications between the controller, the portable unit, and the receiver can be performed properly, because the portable unit is located in the vicinity of the receiver.
Preferably, the apparatus of the invention further comprises an open/close sensor for generating a signal indicating an open/close state of the door. The controller opens a door window when, after unlocking the door, the object sensor continuously detects an object and the open/close sensor continuously outputs a door close signal for a predetermined period t
6
.
By virtue of the above-described structure, after the door is unlocked, the window of the door is opened when the predetermined period t
6
has elapsed without the door being opened even though the object sensor detects an object. That is, the window of the door is opened when a person carrying the portable unit remains within a sensing area of the object sensor for the period t
6
or longer.
Preferably, the controller locks the door when, after the door is unlocked, the object sensor does not detect an object and the open/close sensor continuously outputs a door close signal for a predetermined period t
5
.
By virtue of the above-described structure, the door is automatically brought back to the locked state when the door is not opened after the door is unlocked, and the object sensor comes into an object-undetected state. Therefore, automatic locking can be performed with improved reliability when a person carrying the portable unit does not open the door.
Preferably, the object sensor comprises a slot antenna having an outside door handle, at least the surface of which is formed of a conductive material, a slit formed in the conductive material, and feeding points provided on the conductive material; and the transmitter supplies the feeding points with a radio wave transmission voltage.
In this case, since the outside door handle itself is used as a conductive plate of the slot antenna, only the slit and the feeding points are required to be added to obtain an antenna function. Therefore, the number of parts required for radiation of radio waves is small. Since the outside door handle has a finite size and does not have a completely flat surface, the slot antenna is considerably different from an ideal slot antenna, so that the performance of the slot antenna is considerably low as compared with an ideal performance. However, effective radio waves are radiated within a small area in the vicinity of the door. The number of parts and the number of steps of assembly for providing an antenna are small, and the antenna can be disposed (or formed) in the outside door handle even though the interior or the surface of the outside door handle is metal (conductive material). In addition, since the antenna is inconspicuous, other persons cannot find the antenna.
Preferably, the object sensor comprises changeover switch for changing the transmission output between a high-power output (i.e., high gain) and a low-power output (i.e., low gain). The changeover switch increases and decreases the transmission power of the transmission request signal.
REFERENCES:
patent: 4884055 (1989-11-01), Memmola
patent: 5252965 (1993-10-01), Gidwani et al.
patent: 5276728
Aoki Koji
Hatano Rikuo
Murakami Yuichi
Okada Hiroki
Aisin Seiki Kabushiki Kaisha
Paladini Albert W.
Sughrue Mion Zinn Macpeak & Seas, PLLC
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