| 摘要 |
PURPOSE:To attenuate the back echo with repetition of the reflection, by providing a number of pores having the same order as the length of the radiated ultrasonic wave of an oscillator within the path of the back echo of the probe material and thus scattering the ultrasonic wave to all direction. CONSTITUTION:The ultrasonic wave is injected in a pulse way into the subject 1 from the oscillator 3 attached to the oblique wedge 2, and the state of the subject 1 is observed by the signal wave 4. A number of pores 10 having the same order as the length of the rediated ultrasonic wave of the oscillator 3 are provided on the path in the travelling direction of the back echo 5 of the wedge 2. Thus the back echo 5 is scattered all around by the pores 10, and these scattered waves are reflected many times and in repetition among the pores 10 to be attenuated. As a result, the back echo 5 going again into the subject 1 is erased. The pores 10 are distributed evenly on the path, and at the same time the pore 10 is formed round, triangular or conical. And the apex side of the pore is set to oppose to the travelling direction of the echo 5. |
