Characteristics of a high power ultrasonic array transmitter in air
A high-power ultrasonic array transmitter with 144 transmitting elements for 3D measurements in air has been developed. The sound pressure level of 126 dB was obtained at a distance of 5 m in the air with an ultrasonic frequency of 40 kHz. This value is approximately 32 dB higher than that obtained using a single transmitting element. The characteristics of the array transmitter were studied and compared with simulation results. The experimental results were in good agreement with the simulation results.
Three-dimensional imaging sensor system using an ultrasonic array sensor and a camera
This paper describes a three-dimensional (3D) imaging sensor system that uses an ultrasonic array sensor and a camera. Ultrasonic array sensors can be used to measure the 3D positions of an object. However, they do not have high resolutions. To overcome this limitation, the proposed system uses the camera to measure the shape of an object and combines this information with 3D position data obtained using the ultrasonic array. The relationship between the ultrasonic array sensor data and the image obtained by the camera was clarified. A prototype system was constructed using a camera and an ultrasonic array sensor that has 16 receivers. The theory proposed in this paper was confirmed experimentally. 3D images were obtained that had higher shape resolutions than those obtained using only an ultrasonic array sensor.
Improvement of Ultrasonic Micro Array Sensor Using the Amorphous Fluorocarbon Polymer Film
Arrayed ultrasonic transducers using the piezoelectric thin film (lead-zirconate-titanate film: Pb(Zr 0.52 Ti 0.48 )O 3 : PZT) having multilayer diaphragm structures are fabricated. The variation in resonant frequencies of conventional ultrasonic sensors is 7.3% in standard deviation, although those have the same structure. In order to reduce the variation of resonant frequency, membrane is coated by amorphous fluorocarbon polymer (FC) film (CYTOP, AGC). The variation in resonant frequencies of new ultrasonic sensors is 2.3% in standard deviation. The resonant frequency and Q-value and sensitivity of new ultrasonic sensors are estimated to be on the order of 56.9kHz and 28.3 and 114 µV/Pa, respectively. This amorphous fluorocarbon polymer film is effective for improvement of reception characteristic of ultrasonic sensor. This ultrasonic micro array sensor using the amorphous fluorocarbon polymer film is shown to be useful for three-dimensional object detection system.