Actuators |
Since the changes in width of a crystal are very small, even when high strength electric fields are present, the dimensions of a crystal can be controlled with micro-metre precision. This makes them very useful for high accuracy actuators. Some such uses include:
Speakers – The most common form of loudspeakers use electromagnetism to drive the speakers but the piezoelectric effect can also be used. Opposite to piezoelectric microphones, the voltage is applied across the crystal causing it to oscillate, producing sound waves.
Laser Mirrors – Piezoelectricity is used to align the relatively large mass of a mirror to a great degree of accuracy for optimum conditions for lasers.
Speakers – The most common form of loudspeakers use electromagnetism to drive the speakers but the piezoelectric effect can also be used. Opposite to piezoelectric microphones, the voltage is applied across the crystal causing it to oscillate, producing sound waves.
Laser Mirrors – Piezoelectricity is used to align the relatively large mass of a mirror to a great degree of accuracy for optimum conditions for lasers.
Motors - Piezoelectric motors can operate in a variety of different ways but they all rely on the inverse effect to function. One mechanism produces motors that are effectively stepper motors, a type of motor that rotates 360 degrees in a number of equal steps.
Figure 5 shows a motor employing a locking system to provide motion. First one group of crystals is activated to lock one side, known as the locking crystals. Then the motive crystals (centre) expand to push the locked crystals along the motor path, providing motion. Then the first locking group is released, the other activated and the motive crystals return to the original position. This technique allows very precise control of the motor. |