0 Piezoelectric Device Manufacturers in 2024

What Is a Piezoelectric Device?

Piezoelectric devices are passive devices that control and detect micro-operation using the piezoelectric and inverse piezoelectric effects that occur in dielectric materials such as quartz and quartz.

Because of their simple structure that does not require gears or motors for operation, piezoelectric elements are smaller than other micro-operation mechanism elements.

Uses of Piezoelectric Devices

Piezoelectric devices are mainly used in devices that detect and control micro-motion for industrial applications.

For example, piezoelectric devices are used in vibrometers, where minute changes in force due to vibration are input to the piezoelectric device as pressure, and the voltage generated in the piezoelectric device under pressure is output to obtain a voltage value that is quantified as the magnitude of the vibration.

Piezoelectric drive systems are also used in the stage motion of microscopes, interferometers, and other equipment that requires precise motion.

Piezoelectric device components for such drive systems are called piezoelectric drivers or piezoelectric actuators, and multilayer actuators with multiple layers of piezoelectric devices are also commonly used components.

In these devices, minute movements are achieved by applying minute pulse currents to the piezoelectric devices. Piezoelectric devices are suitable for situations where high responsiveness and precise motion control are required.

Principle of Piezoelectric Devices

Piezoelectric ceramics serve as the primary materials in piezoelectric devices. Piezoelectric materials have polarity, which is an electrical distortion inside the crystal.

A piezoelectric device consists of a piezoelectric material sandwiched between a positive electrode and a negative electrode.

By applying voltage between the electrodes, pressure is applied to the piezoelectric body, which expands, contracts, and displaces as shown by the blue arrow depending on the magnitude of the voltage, and this displacement is used as the driving force, etc. In addition, it is also possible to detect voltage by applying pressure that deforms the piezoelectric device in the opposite direction.

Under normal conditions, the crystal lattice inside the piezoelectric element remains electrically stable by taking in ions from the atmosphere. However, when voltage is applied, the balance is easily disrupted, leading to a change in polarity within the crystal. As a causing the crystal lattice expand and contract in the direction which indicates the displacement of the piezoelectric material.

The piezoelectric device uses this polarity to efficiently transform electrical energy into deformation energy of the device, and is composed of a piezoelectric material sandwiched between electrodes.

In response to the voltage applied between the electrodes, pressure is applied to the piezoelectric body, causing it to deform.

The piezoelectric body can also detect voltage when pressure is applied in the opposite direction.

The deformation of the piezoelectric material in this case is at the level of a few microns at most, due to distortion deformation using the electronic polarity of the crystal lattice of the piezoelectric material.

Therefore, in general, only a few microns of driving force can be expressed, and multiple piezoelectric devices must be combined and stacked if a larger driving force is to be secured.

How to Select Piezoelectric Devices

It is necessary to determine the piezoelectric device that operates appropriately depending on whether the material in which the piezoelectric device is installed and operated is a mass load or an elastic load.

In particular, when the piezoelectric device is used to operate an actual moving structure held via an elastic member such as a spring, it will be under elastic loading conditions. As load is applied to the piezoelectric device, the elasticity of the spring will push back the force exerted by the piezoelectric device, changing the way the force is transmitted.

Specifically, the case in which the force generated when the piezoelectric device presses down on the driving member is transmitted directly to the actually moving component is called mass loading. A constant force in the direction of the blue arrow is applied continuously from the time the voltage is applied to the piezoelectric device.

On the other hand, the elastic load described above is a case in which the force generated when the piezoelectric device presses down on the driving member is transmitted to the actually moving component via an elastic member such as a spring.

From the time the voltage is applied to the piezoelectric device, it is pressed against the resistance of the spring and the force applied to the component gradually increases until it reaches a constant force.

Therefore, if the piezoelectric device can only provide a constant voltage when it is pressed through an elastic member such as a spring, the amount of movement will differ between the first and second halves of the operation.

In addition, since piezoelectric devices have a fixed stroke length, it is important to select a piezoelectric device with a stroke length that can achieve the desired motion.

Piezoelectric Device Materials

There are two types of materials with piezoelectric effect: ceramic-based and film-based.

1. Piezoelectric Ceramics

Lead zirconate titanate (PZT)
PZT is the most widespread piezoelectric ceramic and is used in a wide range of applications primarily in buzzers, vibration sensors, and actuators.

2. Lithium Tantalate (LT)

This single-crystal material is used in electronic devices due to its high stability. The most common application is in electronic devices called SAW filters, which allow only specific radio waves to pass through. It is widely used in cell phones.

3. Piezoelectric Film

Polyvinylidene fluoride (PVDF)
PVDF is a resin film with piezoelectric properties. Although its displacement capacity is not as high as that of ceramics, it can be produced inexpensively and processed into various shapes. It is widely used in home appliances such as proximity sensors for self-propelled vacuum cleaners and touch sensors.

Examples of Products in Which Piezoelectric Devices Are Used

1. Piezoelectric Devices for Lighters

Piezoelectric devices are used in the ignition parts of electronic lighters and gas stoves, taking advantage of the fact that they generate a high-voltage charge when a shock is applied.

While flints (ignition stones) wear out with each use, piezoelectric devices used in electronic lighters can be used semi-permanently as long as they are not damaged, making them suitable for use in refillable gas lighters and the like.

2. Speakers Using Piezoelectric Devices

Piezoelectric devices are also used as sound components, taking advantage of their ability to expand and contract when an electric signal is applied. A thin plate of piezoelectric ceramics is attached to a metal plate to obtain vibration amplitude using spreading vibration to produce a loud sound.

It is mainly used for notification sounds in home appliances, beeps in computers, electronic sounds in clocks, back-up sounds in car cabins, and click sounds in audio equipment.

Some high-end audio products are equipped with piezoelectric speakers as tweeters that produce sounds around 20 kHz, which are barely audible to the human ear, and some produce the effect of broadening the sound in classical music, etc.

3. Piezoelectric Actuators

Piezoelectric devices are also suitable as actuators (drive units) for pushing and pulling objects, taking advantage of their ability to expand and contract with electric signals.

Piezoelectric actuators are used in the drive unit of inkjet printers to realize high-precision ink ejection and dispensing functions for pushing out liquid.

Actuators using piezoelectric devices have the advantage of being smaller than actuators using electromagnetic coils, but they are used only in applications that require minute, high-precision drive amplitudes because they are not as large as coil-type actuators in terms of vibration amplitude.