Vehicle presence notification apparatus
A vehicle presence notification apparatus uses several ultrasonic transducer devices to generate a notice sound by emitting an ultrasonic wave in mid air based on an ultrasonic signal modulated according to an audible sound. At least one of the speaker-use ultrasonic transducer devices is a two-way transducer device that is enabled to perform not only transmission but also reception of an ultrasonic wave. When a vehicle velocity is equal to or greater than a predetermined value, the two-way transducer device is caused to function as an ultrasonic sensor. Thus, even when the generation of any notice sound is unnecessary due to the vehicle velocity being fast, the vehicle presence notification apparatus can be used as an ultrasonic sensor to measure a distance with an obstacle outside of the vehicle.
1. A vehicle presence notification apparatus in a vehicle for reporting a presence of the vehicle to an outside of the vehicle,
the apparatus comprising:
an ultrasonic signal generation section that outputs an ultrasonic signal;
a modulation section that uses the ultrasonic signal as a carrier wave and modulates the ultrasonic signal depending on an audible sound;
a plurality of speaker-use ultrasonic transducer devices that generate a notice sound by emitting an ultrasonic wave in mid air based on the ultrasonic signal modulated by the modulation section; and
at least one sensor-use ultrasonic transducer device that is included in the plurality of speaker-use ultrasonic transducer devices,
the sensor-use ultrasonic transducer device being a two-way transducer device that is enabled to perform not only transmission but also reception of an ultrasonic wave,
the two-way transducer device having
a first function as a speaker to generate a notice sound and
a second function as an ultrasonic sensor to measure a distance with an obstacle outside of the vehicle,
the second function of the two-way transducer device being operated when a velocity of the vehicle is equal to or greater than a predetermined value.
2. The vehicle presence notification apparatus according to claim 1 , wherein
when the velocity of the vehicle is less than the predetermined value,
an operation of the first function and an operation of the second function are switched into each other every a predetermined time period in the two-way transducer device.
3. A vehicle presence notification apparatus in a vehicle for reporting a presence of the vehicle to an outside of the vehicle,
the apparatus comprising:
an ultrasonic signal generation section that outputs an ultrasonic signal;
a modulation section that uses the ultrasonic signal as a carrier wave and modulates the ultrasonic signal depending on an audible sound;
a plurality of speaker-use ultrasonic transducer devices that generate a notice sound by emitting an ultrasonic wave in mid air based on the ultrasonic signal modulated by the modulation section; and
at least one sensor-use ultrasonic transducer device that is included in the plurality of speaker-use ultrasonic transducer devices, the sensor-use ultrasonic transducer device being a two-way transducer device that is enabled to perform not only transmission but also reception of an ultrasonic wave,
the two-way transducer device having
a first function as a speaker to generate a notice sound and
a second function as an ultrasonic sensor to measure a distance with an obstacle outside of the vehicle,
wherein
when a velocity of the vehicle is less than a predetermined value, an operation of the first function and an operation of the second function are switched into each other every a predetermined time period in the two-way transducer device.