An ultrasonic phased array sensor comprising:
- an ultrasonic transducer array including a rigid support plate that has a first surface on one side and a second surface on the other side in a thickness direction, the rigid support plate being provided with a through-hole group including a plurality of through-holes penetrating between the first and second surfaces, a flexible resin film that is fixed to the first surface of the support plate in such a way as to cover the plurality of through-holes, and a plurality of piezoelectric elements whose number is same as a number of the plurality of through-holes, the piezoelectric element being fixed to the flexible resin film in such a way that a middle portion thereof overlaps, in a plan view, the corresponding through-hole and a peripheral portion thereof overlaps, in a plan view, the first surface of the support plate, wherein the through-hole group has an X-direction row formed by m (m is an integer of 3 or higher) pieces of the through-holes that are arranged at a predetermined X-direction array pitch in an X-direction in an X-Y plane of the support plate, wherein the plurality of piezoelectric elements include a plurality of transmission piezoelectric elements forming transmission transducers that generate ultrasonic waves in response to application of a driving voltage signal having a predetermined driving frequency and a plurality of reception piezoelectric elements forming a plurality of reception transducers that generate reception voltage signals in response to reception of ultrasonic waves;
- a transmission signal generation device that generates sine burst wave driving voltage signals for applying the plurality of transmission piezoelectric elements at delay times respectively corresponding to the plurality of transmission piezoelectric elements, the driving voltage signal having the predetermined driving frequency lower than a resonance frequency of the transmission transducer;
- a plurality of detectors that generate detecting signals with widths corresponding to durations of the reception voltage signals respectively generated by the plurality of the reception piezoelectric elements;
- a plurality of delay circuits capable of delaying the reception voltage signals, which are respectively generated by the plurality of detectors, by respective predetermined times;
- an adder circuit that adds output signals of the plurality of delay circuits and outputs an added reception voltage signal;
- a control device that performs control with respect to the transmission signal generation device and the delay circuits;
- and
- a detection device that identifies a position of an obstacle on the basis of a time difference between a transmission timing signal based on the driving voltage signal sent from the control device and a reception timing signal based on the added reception voltage signal sent from the adder circuit, and an azimuth angle sent from the control device,
- wherein the transmission transducer is of a non-resonant type that generates an ultrasonic wave without performing resonant vibration in response to application of the driving voltage signal having the driving frequency, and the reception transducer is of a resonant type that performs resonant vibration in response to receipt of ultrasonic wave having a frequency corresponding to the driving frequency.