| 摘要 |
The ultrasonic probe (11) has an ultrasonic transducer (31) for sending and receiving ultrasonic waves, and a cap (30) covering the ultrasonic transducer (31). The ultrasonic transducer (31) scans a living organism with the ultrasonic waves passing through the cap (30). A meshed area having plural holes (30a) is provided in a portion of the cap (30) for transmitting the ultrasonic waves. By reducing a density interval (pitch of the holes) below a wavelength of the ultrasonic waves, an acoustic impedance of the meshed area is reduced. Water flows into the cap (30) from a sheath (17), and then flows outside the cap (30) through the holes (30a). A concave (30b) can be alternative to the hole (30a) . In addition, the pitch of the holes (30a) or concaves (30b) may be uneven in the meshed area, so as to give an acoustic lens effect to the cap (30a).
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