| 摘要 |
PURPOSE:To suppress deterioration of a picture quality with damping of an ultrasonic wave decreased by forming an acoustic lens in multi-layer constitution in which a layer, formed of material with a sound speed in permeating slower than a detected object, and a layer, formed of material with the sound faster than the object, are combined respectively in one ore more. CONSTITUTION:A so-called cap type acoustic lens 6 is constituted of the first layer 6a, in which a sound speed is slower than that when an object is the human body, and the second layer 6b in which the sound speed is faster than the object. The first layer 6a, with a section protrusive, has a shape of thinning a part 6a1 of so-called clog and also a central part 6a2. Also, as a material quality, a material with the speed slower than the living body, typically silicone rubber with the speed about 1000m/s, is used. The second layer 6b is formed in a section almost squared with one side open with the first layer 6a arranged in the bottom part. And, as the material quality, a rubber material, mainly composed of rubber such as neoprene rubber, butyl rubber, Buna, etc., or a resin material such as polyisobutylene, polyethylene, etc., is used with the speed faster than the living body, that is, about 1500 to 2000m/s. |
