| 摘要 |
PROBLEM TO BE SOLVED: To provide an acoustic matching layer that has lower acoustic impedance by further increasing the mixing quantity of hollow glass balloon grains, and an ultrasonic sensor using the acoustic matching layer. SOLUTION: A trace amount of carbon grains 3 having a small grain size are mixed and dispersed in a resin in addition to hollow glass balloon grains 2. At such a time, the D90 grain size of carbon grains 3 becomes 1/10 or less of the D10 grain size of hollow glass balloon grains 2. Thus, a trace amount of the carbon grains 3 operate as a bearing between the hollow glass balloon grains 2 and the viscosity of the resin before thermosetting is lowered to facilitate stirring, so that the mixing quantity of hollow glass balloon grains 2 is increased to realize the lower acoustic impedance. COPYRIGHT: (C)2005,JPO&NCIPI
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