| 摘要 |
<p>The transducer (1) has a matching layer (5) that is made of a cross linked polyurethane hard foam and is connected to a piezo-ceramic disc (3). The hard foam has a hollow ball made of glass or plastic and is filled with a light filler material. The matching layer has a density in a range of 400 to 900 kilogram per meter cube, and is stable up to a temperature of 120 degree Celsius. The matching layer or transducer is coated with a protected layer in an area of a sonic radiation surface (8).</p> |
