| 摘要 |
<p>A fluid detector for determining a presence of a fluid within a container includes a piezoelectric element that outputs a first ultrasonic signal in response to an input electrical signal and a lens with an upper portion and a lower portion. The piezoelectric element is coupled to the upper portion of the lens so that, when the lens is disposed adjacent the outer surface of the wall such that the lens is intermediate the piezoelectric element and the wall, the lens focuses the first ultrasonic signal toward the wall so that the first ultrasonic signal enters the wall.</p> |
