The piezoelectric actuator is composed of a piezoelectric ceramic sheet attached to an elastic substrate. It expands and contracts through an alternative voltage signal to make displacement and vibration. Such a conversion from electrical energy to mechanical energy is called the inverse piezoelectric effect.

Depending on the structure of the actuator, it can be divided into “Unimorph” or “Bimorph”type.

Unimorph actuator consists of a piezoelectric ceramic sheet attached to one side of an elastic substrate as Figure 1 shows.

The structure of Bimorph on the other hand, consists of two piezoelectric ceramic sheets attached to both sides of an elastic substrate, refer to Figure 2.

The size of the actuators can be adjusted in different size and shapes according to customer needs, such as rectangular, round, or square shapes.

Figure 1 : Structure of Unimorph type actuator
Figure 2 : Structure of Bimorph type actuator

Piezoelectric actuators have the following characteristics:

  • Lightweight
  • Fast response time
  • Low noise
  • Stable
  • Various vibration modes can be generated according to different signals

Piezoelectric actuators will produce different displacements and forces according to different driving voltages, as demonstrated in Figures 3 and 4, so the driving voltage can be controlled to obtain the required displacement and force.

Figure 3 : Unimorph PZT module:  Relationship between Force and Displacement under different driving voltages
Test Conditions：
1.     Module type：Unimorph PZT module
2.     Piezo ceramic size：59.3mm*19.3mm*0.2mm
3.     Matrix material size : 65mm*20mm*0.1mm
4.     Free length：43mm
5.     Test voltage：DC 50V/75V/100V/125V/150V
Figure 4 : Bimorph PZT module: Relationship between Force and Displacement under different driving voltages
Test Conditions：
1.   Module type：Bimorph PZT module
2.   Piezo ceramic size：59.3mm*19.3mm*0.2mm
3.   Matrix material size : 60mm*20mm*0.1mm
4.   Free length：22.7mm
5.   Test voltage：DC 20V/40V/60V/80V

Piezoelectric actuators can mainly be used in haptic feedback, such as the touch panel of laptops, smartphones, and other electronics. Refer to Figure 5 for the illustration of haptic feedback.

Figure 5: illustration of haptic feedback

Piezoelectric actuators will produce different vibration accelerations with different driving voltages and frequencies, as shown in Figure 6 and Figure 7, so we can get the vibration tactile feedback we desire by manipulating the driving voltage and frequency.

Figure 6 : Unimorph PZT module: The relationship between vibration acceleration and driving voltage and frequency
Test Conditions：
1.   Module type：Unimorph PZT module
2.   Piezo ceramic size：59.3mm*19.3mm*0.2mm
3.   Matrix material size : 65mm*20mm*0.1mm
4.   Accelerate meter：TI DRV-ACC16-EVM
5.   Test voltage：Sine wave 0~100V/0~140V
6.   Test position：Accelerator meter on center of unimorph PZT module
Figure 7 : Bimorph PZT module: The relationship between vibration acceleration and driving voltage and frequency
Test Conditions：
1.     Module type：Bimorph PZT module
2.     Piezo ceramic size：59.3mm*19.3mm*0.2mm
3.     Matrix material size : 65mm*20mm*0.1mm
4.     Accelerate meter：TI DRV-ACC16-EVM
5.     Test voltage：Sine wave +50V/-50V; +70V/-70V
6.     Test position：Accelerator meter on center of bimorph PZT module

Unictron has nearly 30 years of experience developing and manufacturing piezo ceramics and its modules. We have our own unique formulation that enabling tailor-made service to maximize the performance in different applications. Whether it’s actuator’s simulation, design or manufacturing, Unictron is always available to provide the best and optimal actuators according to your needs.