| 摘要 |
PROBLEM TO BE SOLVED: To receive properly an ultrasonic wave propagated inside a measuring object even in a low frequency domain having a frequency of below 500 kHz, and to perform various measurements on the measuring object accurately in the noncontact state over a wide range. SOLUTION: In this electromagnetic ultrasonic sensor 10 equipped with a magnetic flux generation part 11 for generating a magnetic flux 102 to the measuring object 100 comprising a conductor, and a coil 12 arranged on a crossing position with the magnetic flux 102 generated from the magnetic flux generation part 11, as for permanent magnets 11a, 11b constituting the magnetic flux generation part 11, at least either end of one-side end facing to the measuring object 100 and the other-side end on the opposite side to one-side end is formed to have a sawtooth shape 11k. Hereby, since the length in the thickness direction (direction connecting the S-pole to the N-pole) of each permanent magnet 11a, 11b does not become constant, generation of a pseudo standing wave in each permanent magnet is prevented. COPYRIGHT: (C)2008,JPO&INPIT
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