| 摘要 |
An ultrasonic beam shaping device includes a plate-like beam shaping element formed of opaque material. The beam shaping element has first and second conical surfaces, with a common axis, formed as opposite surface portions of the beam shaping element. A cylindrical aperture is formed in the beam shaping element along the common axis of the first and second conical surfaces such that the cylindrical aperture is also co-axial with the conical surfaces and passes through the conical surfaces. The beam shaping element thus has a circular open end at each conical surface.
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