| 摘要 |
PROBLEM TO BE SOLVED: To provide an ultrasonic sensor which is waterproof, moisture-proof, and airtight and improves the sensitivity and reverberation characteristics. SOLUTION: One principal face 101 of an acoustic matching layer 10 has an edge part 61 fixed to the upper end face of a cylindrical case 50, and the other principal face 102 of the acoustic matching layer 10 is covered with a first waterproof material 30, and a side face 103 of the acoustic matching layer 10 is covered with a second waterproof material 40, and the second waterproof material 40 is joined to the first waterproof material 30 without a gap in a vicinity 61 of the edge part of the other principal face 102 of the acoustic matching layer 10 and is joined to a case 50 without a gap on a side face 63 of the case 50. Consequently, the first very thin waterproof material can be easily provided on the other principal face of the acoustic matching layer to realize efficient work and cost reduction. Since a node of the acoustic matching layer can be bound by highly rigid waterproof materials, the ultrasonic sensor having satisfactory sensitivity and reverberation characteristics is obtained.
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