Object detection device

An object detection device comprising:

• a wave transceiver unit configured to transmit a search ultrasonic wave and receive an ultrasonic wave having an amplitude, the search ultrasonic wave including at least one pulse signal;
• a signal generation unit configured to generate the at least one pulse signal, the at least one pulse signal including at least one identification code for identifying the search ultrasonic wave, the at least one identification code being comprised of a frequency change;
• a drive control unit configured to receive the at least one pulse signal from the signal generation unit and generate a drive current or a drive voltage, the drive control unit configured to adjust an amplitude of the at least one pulse signal using the drive current or the drive voltage;
• a drive unit configured to apply the drive current or the drive voltage to the wave transceiver unit to generate the at least one pulse signal;
• and
• an object determination unit configured to compare a code included in the received ultrasonic wave with the at least one identification code included in the at least one pulse signal to determine whether the received ultrasonic wave is a wave resulting from reflection of the search ultrasonic wave, the object determination unit configured to determine whether an object is present in a predetermined detection range of the object detection device based on the amplitude of the received ultrasonic wave,
• wherein
• the drive control unit is configured to:
• increase, during a predetermined amplitude rise time, at least one of the drive current and the drive voltage from a predetermined value to be larger than the predetermined value, the predetermined amplitude rise time comprising a predetermined time from a start of a generating of a pulse signal representing a code of one bit, the code of one bit comprising one bit of the at least one identification code, in which an up-chirp signal represents a code “0” and a down-chirp signal represents a code “1”, the up-chirp signal comprising a signal in which a frequency increases as time passes, and the down-chirp signal comprising a signal in which a frequency decreases as time passes;
• reduce, during the predetermined amplitude rise time, the at least one of the drive current and the drive voltage to the predetermined value before the predetermined amplitude rise time has elapses;
• and
• reduce the at least one of the drive current and the drive voltage to be equal to or less than the predetermined value in response to determining that the predetermined amplitude rise time has elapsed, wherein
• during the predetermined amplitude rise time, the at least one pulse signal comprises a constant frequency for a predetermined number of pulses and thereafter changes in frequency after the predetermined number of pulses.