An ultrasonic transducer can be defined as a transducer used to convert a type of energy into ultrasonic vibrations.
Through these ultrasonic vibrations, the transducer measures the distance of the object.
In this article, we’ll be discussing what ultrasonic transducers are and how it works.
We’ve also included the advantages, disadvantages and how we can maintain it.
What are ultrasonic transducers?
An ultrasonic transducer is a sound-related sensor.
These transducers send electrical signals to the object, and once the signal reaches the object, it returns to the transducer.
In this process, the transducer does not measure the distance of an object by the intensity of the sound.
These sensors use ultrasound to measure some parameters.
It has a broad range of uses and applications in various fields.
When an electrical signal is applied to an ultrasonic transducer, it vibrates in a characteristic frequency range and produces sound waves.
These sound waves move, and whenever any obstacle appears, these sound waves send back sensor data.
Finally, these data are converted into electrical signals.
Sounds produced above the range of human hearing are called ultrasound.
An ultrasonic transducer is an acoustic sensor.
While ultrasound typically starts at 20 kHz, most ultrasound transducers start at 200 kHz depending on their application.
In the medical field, ultrasound transducers are used in diagnostic tests, surgical equipment to treat cancer, visceral examinations, cardiac examinations, ophthalmology, uterine examinations, etc.
How do they work?
When an electrical signal is applied to this transducer, it vibrates in a specific frequency range and produces sound waves.
These sound waves travel and whenever any obstacle is encountered, these sound waves are reflected back from the transducer to inform the echo.
At the end of the transducer, this echo is converted into an electrical signal.
Then the transducer calculates the time interval between sending the sound wave and receiving the echo signal.
These transducers are superior to infrared sensors because these ultrasonic transducers or sensors are not affected by smoke, black matter, etc.
Ultrasonic sensors are good at suppressing background interference.
In recent years, there has been an increase in the use of composite devices that replace the usual solid ceramic discs or plates with micromachined parts.
They are miniature piezoelectric ceramic cylinders fixed in an epoxy matrix.
Composite elements can provide higher bandwidth and higher sensitivity in many fault detection applications.
Piezoelectric elements produce sound waves when stimulated by electrical impulses, and voltages when vibrated by a return signal.
This special element prevents damage to the wear plate or acoustic lens and is supported by a piece of damping material that mutes the transducer after the sound pulse is generated.
The ultrasonic subassembly is mounted in a housing with suitable electrical coupling.
These probes used in imaging systems readily incorporate multiple individual transducer assemblies into a single design.
Dual-element sensors are commonly used in corrosion detection systems, except that they have distinct transmit and receive sections, separated by sound barriers and integrated delay lines to direct and combine acoustic energy, rather than wear plates or mirrors.
Types of Ultrasonic Transducers
1. Linear Ultrasonic Transducers
In Linear ultrasonic transducers, the piezoelectric crystals are arranged in a straight line, the beam shape is rectangular, and the near-field resolution is good.
You can use this sensor for various applications such as:
- Blood vessel examination
- Venipuncture and vascular visualization
- Chest examination
- Thyroid examination
- Tendons and joints examination
- Intraoperative laparoscopy
- Body Fat and Muscle Thickness Measurements for Daily Health Checks and Locomotive Syndrome Checks
- Photoacoustic Imaging or Ultrasonic Velocity Change Imaging
2. Phased Array Ultrasound Transducers
This transducer, named after the arrangement of piezoelectric crystals, called a phased array, is the most commonly used crystal.
The beam spot is narrow but expands depending on the frequency of the application.
In addition, the beam shape is almost triangular and the near-field resolution is poor.
You can use this sensor for various applications such as:
- Cardiac tests(including transesophageal tests)
- Abdominal examination
- Brain examination
3. Endocavitary Transducers
These probes give you the opportunity to perform an internal examination of the patient.
Therefore, they are designed to fit specific body orifices.
Typically, they have a small footprint and have a frequency range of 3.5Mhz to 11.5Mhz.
It is often used in cardiology to better understand the heart through the esophagus.
4. Pencil Transducers
Also known as a CW Doppler probe, it is used to measure blood flow and speed of sound in blood.
The probe has a small footprint and uses low frequencies that range at usually 2Mhz–8Mhz.
5. Convex Transducers(Standard)
Convex transducers are known as the standard ultrasonic transducers.
They are also known as curved transducers because the piezoelectric crystal arrangement is curved.
In addition, the beam shape is convex and the transducer facilitates in-depth inspection.
In addition to convex sensors, there is a subtype called micro convex sensors.
It has a much smaller footprint, and typically, doctors use it for neonatal and pediatric applications.
You can use this sensor for various examinations such as:
- Abdomen
- Blood vessel
- Nerve examinations
- Musculoskeletal
- Obstetrics and Gynecology
- Vagina and rectum examinations
- Organ diagnosis
Advantages and Disadvantages of Ultrasonic Transducers
Ultrasonic transducers have different benefits.
They are capable of measuring any type of material.
They can also perceive all types of matter.
They are generally not affected by water, dust, or temperature.
In any environment, ultrasonic transducers may work under the right conditions, but they can also have flaws.
Advantages
- Ultrasonic transducers work well in any type of environment.
- These ultrasonic transducers can measure any type of material. They can perceive all types of materials.
- Ultrasonic transducers are not affected by temperature, water, dust, or anything.
- It can also measure at high sensing distances.
Disadvantages
- It has problems reading reflections from small, fragile, thin, and soft objects.
- Ultrasonic transducers are sensitive to temperature changes.
This temperature change may alter the ultrasonic response.
How to Maintain and Clean An Ultrasonic Transducer?
- Do not throw, drop or strike the ultrasonic transducer.
- Be careful not to damage the conduit of the ultrasonic transducer.
- Wipe the gel on the transducer after each use.
- Do not brew with alcohol-based products.
