The Versatile Power of Piezoelectricity Across Modern Applications

1.Introduction
2.Applications for Consumer Electronics
3.Application in Automotive Electronics
4.Applications in Industrial Control&Medical Devices&IoT
5.Conclusion

Introduction
Piezoelectricity is a very specific physical property that is exhibited by some crystals, ceramics and polymer-based materials. When mechanical stress is applied these materials which will create an electric charge. On the other hand, when an electric field is applied, the material changes its dimensions or generates vibration. These phenomena are referred to as the direct and the inverse piezoelectric effect. Together, they make it possible to use one material to act both as a sensor and as an actuator. Because of its dual nature, piezoelectricity has become an important basis for today's electronic systems.
While it has been realized as piezo since over a century ago, commercial uses greatly increased after the creation of piezo ceramics such as PZT (lead zirconate titanate). These ceramics have the advantages of strong electromechanical coupling, high stability and can be formed in a ring, tube, plate or multilayer form.
Piezoelectricity offers some important advantages that include high sensitivity to mechanical input, response times in the microsecond domain, low level of energy consumption, small size, immunity to electromagnetic interference. Different from electromagnetic devices, piezoelectric components do not involve a combination of coils, magnets and heavy mechanical people, whereas compounds are therefore reliable and durable. These strengths have helped piezoelectric technology to have viable uses from consumer electronics, automotive electronics and industrial control&medical devices&IoT. The following blog describe the role that piezoelectricity plays in supporting these applications.

Applications for Consumer Electronics
The demands of the consumer electronics market are for components that are thin, efficient and capable of precise performance. Piezoelectric devices satisfy all these requirements and the usage of piezoelectric devices is growing as they start producing smaller and more interactive devices.
1.Haptic Feedback
Piezoelectric actuator in practice highly used in haptic feedback systems. Compared to traditional vibration motors, piezoelectric actuators have better response speed and better vibration type, even support local tactile feedback which response time is capable of several tens of microseconds. Haptic feedback based on piezoelectricity makes realistic sims (surface textures) and button-clicks possible on smartphones, tablets, laptops and gaming devices.
2.Ultrathin Audio Components
Piezoelectric speakers and buzzers function from the inverse piezoelectric effect. Alternating voltage is applied to the ceramic element which vibrates to produce sound. These audio components offer high reliability and minimal electromagnetic noise which is crucial for devices that have wireless intensive capability. Piezoelectric speakers can be made thinner than 1 mm, making it possible to introduce new products that are held very thin, such as ultra-slim smartphones, AR/VR glasses and lightweight wearable products.
3.Ultrasonic Biometrics and Sensing
Now, few of the smart phones and smart devices relies on ultrasonic technology. Piezoelectric ultrasonic transducers are used for
fingerprint recognition module, proximity sensors, gesture detection systems, internal haptics and audio playback.
Ultrasonic fingerprint sensors work with the help of acoustic waves that penetrate through the glass and OLEDs layers, whereby they can offer a higher level of security while also contributing to better performance with wet or dirty fingers. The reliability of piezoelectric materials makes such sensing applications ideal for use in these applications at high frequencies.
4.Small-Scale Energy Extraction
Piezoelectric materials are able to convert daily motions (tapping, walking, vibration or acoustic energy) into electricity. While the energy gathered is small but it is enough for the ultra-low-power electronics. Research has shown that with wearable piezoelectric harvesters power levels between 1mW and 4mW can be provided during normal physical activity. This capability lends itself to battery-free sensors, wireless tags and remote-control devices, allows these devices to have a longer life expectancy and become less reliant on the traditional battery.

Application in Automotive Electronics
The automotive industry requires sensors and actuators that can function reliably in changing temperatures and environmental stresses such as vibration and long-term environmental stressors. 
Piezoelectric materials exude these conditions.
1. Ultrasonic Parking Sensors & Driver Assistance Sensor
Ultrasonic parking sensors involve piezoelectric switching transistors to send out and obtain sound waves, generally of a frequency between 40kHz and 60kHz. These ultrasonic sensors determine time-of-flight of reflected sound waves to figure out the distance of obstacles in its vicinity. Because ultrasonic waves aren't affected by lighting conditions, so piezoelectric sensors can be accurate even in the dark, rain, dust and fog weather. These features also have led them to be part of advanced driver-assistance systems (ADAS) to help perform low speed maneuvering and autonomous parking.(want to know more about ultrasonic parking sensors, you can turn to this blog《How Does Ultrasonic Sensor Help in Parking the Car?》)
2. Precision Fuel Injection
Modern gas and diesel engines have piezoelectric actuators in the fuel injectors. These actuators provide very high rates of response-times, the time can reach magnitude of 100 microseconds which provide precise control of fuel spray patterns. As a result, engines can have reduced emissions, increased fuel economy and smoother operations. 
3.Detection of Knock and Vibration Monitoring
Piezoelectric knock sensors are used to monitor the engine vibration for any abnormal combustion of the engine. They help provide real-time feedback to the engine control unit to help with adjusting the ignition timing and protecting the engine from damage. Because of the mechanical and thermal properties of piezoelectric ceramics, they can be used at high temperatures and mechanical loads and are therefore ideal for installation adjacent to engine blocks.
4.Electric vehicles
Electric vehicles (EVs) also have piezoelectric components for haptic control interfaces, pressure sensing for the batteries and ultrasonic sensors at the form of the side. Due to the greater connectivity and lightness expected in EV platforms in the future, the need for small and pronouncement piezoelectric sensors is growing at a very fast pace.

Applications in Industrial Control&Medical Devices&IoT
1.Automated Processes and Monitoring of Industries
In industrial environments, piezoelectric sensors are very useful in vibration analysis, machine health monitoring and pressure measurement, etc. They are highly sensitive so you can early detect the wear or imbilance of machine. For instance, piezoelectric accelerometers could measure a small variation in the vibration of a machine, and it could be used to perform predictive maintenance.
Piezoelectric actuators are also used in semiconductor manufacturing for precision positioning, for optics alignment, in laser systems, as well as micro-printing and nanotechnology. Their nanometer level resolution and fast response makes them suitable for automation applications that require high speeds.
2.Diagnosis and Treatment in the Medical Field
Medical ultrasound systems are completely based on piezoelectric transducers. These types of transducers are used to send out acoustic waves and then catch the echo of these waves in order to make internal body images.
Piezoelectric nebulizers and atomizers are used for derive medicine into brisk mist for air treatment. They are energy-efficient and quiet which is a boon in portable medical devices. Additionally, ultrasonic surgical tools and dental scalpels are employed that draw on horn resonance vibration that allows precise cutting with minimal tissue damage.
3.IoT and Smart Infrastructure
Piezoelectric technology is playing a big role in IoT systems because of small size and low power consumption. Some commonly used applications include: Wireless machine vibration sensors, Structural monitoring of bridges and buildings, Energy scavenging units for battery free IoT devices, Presence and distance detection by ultrasound, Microphones and Acoustic sensor in smart speaker.
Smart cities also use piezoelectric sensors to monitor the flow of traffic, detect abnormal vibration, and to monitor environmental conditions. 

Conclusion
Piezoelectricity has been transformed into a force in various industries because of its dual sensing and actuation capability, fast response time, small size and astonishing energy efficiency. In the area of consumer electronics, it makes possible sophisticated haptics, thin audio modules, ultrasonic biometric and energy harvesting. In automotive systems, it is used for precision fuel imbalance control, parking assistance and vehicle monitoring for higher functionality. In industrial applications, medical applications and IoT applications, high-accuracy sensing, imaging, positioning, monitoring of structures, etc.
As multilayer ceramic structures and for thin-film piezoelectric materials, the performance and reliability of piezoelectric devices will keep increasing. Piezoelectricity technology will continue to be a core technology that enables the next generation of smart devices, cleaner transportation, modern healthcare and smart cities.

BeStar Sensortech Co., Ltd. as a leading global provider of multilayer piezoelectric ceramics and device solutions, we will provide you high-quality piezoelectric ceramic components and solutions. If you have any requirements, you can contact our team of engineers right now for advice and a quote.