To do all this, though, you need a device called a transducer.

但完成该过程，你不能缺少一台叫做‘压电式换能'的设备。

Because of this, our ears evolved into something we now call a transducer.

正因为如此，我们的耳朵进化成了我们现在称之为传感的东西。

A transducer is anything that changes energy from one form to another.

传感可以是任何东西，它可以将能量从一种形式转换为另一种形式。

That vertical piece is the force transducer.

那垂直的部件就是力传感。

The other force transducer's right up on the top.

另一力传感就在顶部。

Then, the transducer uses the reflected waves to create an image.

然后， 换能反射波创建图像。

To make a transducer by painstakingly micro-machining a brittle block of ceramic material can take many hours of work, though.

压电式换能需要到陶瓷材料，而精密地加工一块精细的陶瓷材料就要耗费几小时的工作时间。

Transducers are made from arrays of tiny piezoelectric structures that convert electrical signals into ultrasound waves by vibrating at an appropriate frequency.

压电式换能是由具有‘压电'效应的一系列敏感件机构组成。敏感件机构通过‘定频'震荡将电信号转换成超声波。

However GE, a large American conglomerate, is now proposing to make ultrasound transducers by " additive" manufacturing—or three-dimensional printing, as it is also known.

而GE作为美国的一庞大的企业集团正考虑采‘对比添加式'的加工流程（或者又称大家所熟悉的‘3D印刷'）来加工超声波压电式换能。

The GE process for making a transducer begins by spreading onto the print table a thin layer of ceramic slurry containing a light-sensitive polymer.

GE对加工换能的方法是首先在印刷台上撒上薄薄的一层陶瓷粘土，其中混入一种光敏聚合体。

Doctors can use an ultrasound transducer to make ultrasound waves that travel through your body, and reflect off different squishy bits, like organs, or a fetus.

医生可以超声波换能产生穿过您身体的超声波，并反射不同的软质部分， 如官或胎儿。

The waves are then reflected back from areas where there is a change in density and on their return the transducer works in reverse, producing a signal which the scanner can process into a digital image.

超声波会从密度发生变化的介质反射回来，这时压电式换能会反向操作产生信号，再经过扫描的处，最后进行数字成像。

So for example, we can make them all come together to a point, and they can we can make transducers from the bottom and from the top come to two different points that are half a wavelength apart.

举例子，我们可以将它们汇聚到一点上，我们可以让换能分别从底部和顶部到达两相距半波长的点。