FOREIGN MATTER ADHESION DETECTION DEVICE AND FOREIGN MATTER ADHESION DETECTION METHOD

摘要

PROBLEM TO BE SOLVED: To provide a foreign matter adhesion detection device and a foreign matter adhesion detection method which can stably detect adhesion of a foreign matter to an ultrasonic sensor regardless of variation in transmission voltage and detect adhesion of a foreign matter in the case where the reflection wave is not received by the ultrasonic sensor.SOLUTION: A foreign matter adhesion detection device 100 comprises: a phase difference detection part 6 which detects the phase difference Δθ between an input signal corresponding to the applied voltage to an ultrasonic sensor 3 and an output signal corresponding to the load current flowing in the ultrasonic sensor 3 with the applied voltage; and an abnormality determination part 7 which determines whether or not the foreign matter adheres to the ultrasonic sensor 3 by comparing the value of the phase difference Δθ with a threshold.SELECTED DRAWING: Figure 1