Piezoelectricity is a type of electricity. Its name is from the type of material that produces the electric charge. The prefix piezo comes from ‘piezo’ or ‘piezein’, which is a Greek word that means to stress, press, or put under pressure. The use of the word ‘piezo’ signifies the presence of piezoelectric effect. This effect has been significantly used since the time that it was discovered.
It was towards the end of the 1800s that physicist brothers Pierre and Jacques Curie accidentally discovered the existence of piezoelectric effect. That time, they were using quartz crystals in an experiment. The brothers noticed that the crystals produce electric charge when they are put under mechanical stress. Piezoelectric effect is the name that the brothers gave to their discovery. Basically, piezoelectricity is pressure-induced electricity.
The French physicist brothers made further experiments which led them to discover inverse piezoelectric effect. This effect happens when an electric field is applied to a piezoelectric material. The Curies noticed that crystals deform when they come in contact with an electric field. Later on, scientists learned that ultrasonic waves can be produced by this effect. They made further studies and experiments and they soon developed sonar, a navigational technique that uses sound waves. Sonar was first put to use during the World War I. It was used to detect the presence of submarines.
Today, pieozoelectric effect is widely used even in our everyday lives. One item that is commonly seen in a household is a gas stove lighter. When the button of the lighter is pressed, a small piece of piezoelectric material is hit by the lighter’s hammer. An electric charge is created from this contact. This electric charge subsequently creates a spark that fires up the gas. Cigarette lighters and gas barbecue grills are two of the other daily used items that use piezoelectricity.
Importance of Piezoelectric Effect in Nanopositioning
The nanopositioning industry benefits a lot from piezoelectric effect. Materials that possess piezoelectric properties, like ceramics and crystals, are very effective actuators. Because of the capability of such materials to produce electrical and mechanical energies, piezoelectric actuators are able to create accurate movements. The nanopositioning industry has been using these devices for a long time.
But there is a problem with natural piezoelectric materials. The piezoelectric effect possessed by these materials is not enough to accurately detect positions. As a solution to this problem, artificial piezoelectric materials were produced. Lead zirconate titanate and lead magnesium niobate are artificial piezoelectric ceramics that have a high level of piezoelectricity. Because of that, the nanopositioning industry makes use of them a lot, especially in the production of sensors and actuators. To create a bigger displacement while operating at low voltage, several layers of piezoelectric materials are used. Nowadays, the piezoelectric actuators used are encapsulated ceramics. These are very reliable and long lasting.
Characteristics of Piezoelectric Actuators
There are several reasons why nanopositioning industry prefers piezoelectric actuators. One reason is that in the nanometer, these actuators can reach steps that have high frequencies. The lack of mechanical parts makes it possible for these actuators to be highly repeatable. The capability of piezoelectric actuators to move various weights is also an advantage. Moreover, this type of actuators are operated using low voltages. Because of this, expenses for power supply are considerably low. The durability of piezoelectric actuators makes these actuators easy to maintain.
Piezoelectricity in Hexapod Precision Positioning
Piezoelectric materials are used in flexure guiding systems. These guiding systems are used in hexapod precision positioning systems. Hexapod precision positioning platforms that use piezoelectricity are far better than hydraulic hexapods. They are hard and they respond quickly. These characteristics make it possible for these precision positioning platforms to act as vibration cancellation systems as well as positioners.