You shall find the use of an ultrasonic transducer in various settings, such as flaw detection, gauging thickness, material research, and medical diagnostics, the biomedical world, nondestructive application evaluations, as well as for penetration of think materials. It relies on the principle of transformation of sound energy into electrical energy and the reversal of this process. It can thus generate and pick the ultrasounds, which is how it manages to tell the distance. It comes with three main parts, and other smaller parts. They are the piezoelectric crystal, wear plate, and backing; acoustic matching layer; and the acoustic lens.
The piezoelectric crystal forms the heart of the gadget. It shall go through a series of rarefactions and compressions for it to convert electrical energy into ultrasonic energy, and vice versa. There are electrodes placed on each side of the crystal. As a vibration hits it from outside, it shall use it to make a voltage. The crystal is in the form of strips on which electrodes are affixed. A strip has the size of a strand of hair. The unit shall rely on these to tell the distance.
the crystal is them protected from the action of the environment by a wear plate. It is what shall keep the crystal form wear and tear, as well as corrosion. IT also has the added function of being an acoustic transformer between water, wedge, crystal, or delay line.
There is also the backing material, which is made of a substance dense enough to fulfill its attenuating duties well. There is normally energy radiating from the back of the crystal, that needs to be absorbed if the crystal is to remain accurate. This unit shall minimize the excessive vibration, which allows the element to generate ultrasonic waves that have a shorter pulse length, which produces a much improved image resolution.
There is also the acoustic matching layer, which lies between the object and piezoelectric element. Its purpose is to ensure the element does not get reflected off a target, since there is a big difference in acoustic impendence between the object and piezoelectric element. The acoustic matching layer shall therefore see to it that the generated waves go into the object more efficiently. This layer is constructed from different resin materials which allow the unit to have enough acoustic impendence value.
The acoustic lens shall be the gray section that looks like a rubber attached to the tip of the probe. Acoustic waves transmitted from the probe usually spread out and do so fast. This lens shall control their spreading by getting them to focus, thereby giving a better image resolution.
There are many brands, designs, and styles to this device. You need to be careful where you get your device from.