| 摘要 |
PROBLEM TO BE SOLVED: To prevent erroneous detection of received wave signals as precisely as possible even in cases of piezo-electric ultrasonic-generating elements having a property of received wave signals of initial lower rising and subsequent gradual growth. SOLUTION: A first, a second and a third sensors S1, S2a and S3a are respectively linearly arranged along the right and left directions and a vertical direction perpendicular thereto on a substrate 1 of an array sensor 2, and when a wavelength of ultrasonic wave generated from an acoustic source isλ, the second sensor S2a is disposed at a space L of less thanλ/2 from the first sensor S1 and the third sensor S3a is disposed at a space of n×λ(n: a natural number) from the first sensor S1. A control section 3 runs a prediction means obtaining a predicted value of a wave receiving time of the third sensor S3a by multiplying a difference of wave receiving times between the second sensor S2a and the first sensor S1 by n×λ/L and a confirmation means employing only the received wave signals detected within a predetermined period from the predicted value in the third sensor S3a as correct signals. COPYRIGHT: (C)2010,JPO&INPIT |
