ULTRASONIC SENSOR

• Main Authors: TAKANASHI ISAO, SHIMIZU OSAMU
• Format: Patent
• Language: English
• Published: 24.05.1989
• Subjects: ANALOGOUS ARRANGEMENTS USING OTHER WAVES; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION ORRERADIATION OF RADIO WAVES; MEASURING; PHYSICS; RADIO DIRECTION-FINDING; RADIO NAVIGATION; TESTING

PURPOSE:To make the sensor thin by providing ultrasonic wave transmitter receivers in the same direction and arranging their center of vibrations on the same plane and on the same circle. CONSTITUTION:A driving circuit 6 incorporates an oscillator and sends an electric signal intermittently to the ultrasonic wave transmitter receivers 1-4 which are connected in parallel. This output timing is controlled by a timing generating circuit 7 and the signal is radiated in the air by the transmitter receivers 1-4 at the same time. Further, the circuit 7 controls the driving of a receiving circuit 8 and outputs a driving signal to the circuit 8 for a predetermined time after sending the driving signal to the driving circuit 6, thereby making the transmitter receivers 1-4 ready to receive reflected electric signals from a body. In this case, the ultrasonic waves are out of phase and sound pressure is lowered except at the point where the ultrasonic waves sent by the transmitter receivers 1-4 coincides all in phase with one another. Consequently, the radiation range of sound pressure level is limited to a narrow range, directivity is obtained without using any horn, and the structure is reduced in size and thickness.