| 摘要 |
<p>A Sell-type transducer for use in an ultrasonic ranging system for a camera has a hollow base containing a floating backplate having a grooved surface in contact with the non-metallic surface of a metallized plastic diaphragm stretched across the base. A spring arrangement urges the floating backplate into engagement with the diaphragm to maintain tension thereon in the event long-term plastic flow occurs in the diaphragm. Improved side lobe suppression is achieved by progressively decreasing the depth of the grooves as the periphery is approached. Further, for repeatability, the crests of the grooves define a convex surface.</p> |
