(位移传感器专业英语）Piezoelectric Technologies.ppt

Member: Yanlong Mao, Jiahao Huo. Xiaomin Liu, Yulin Zhao, Fei Wu, Yongbin Yang, Qingdong Sun. Abstract The piezoelectric effect is a property that exists in many materials. The name is made up of two parts; piezo, which is derived from the Greek work for pressure, and electric from electricity. The rough translation is, therefore, pressure - electric effect. In a piezoelectric material, the application of a force or stress results in the development of a charge in the material. This is known as the direct piezoelectric effect. Conversely, the application of a charge to the same material will result in a change in mechanical dimensions or strain. This is known as the indirect piezoelectric effect. Contents 1. Basic Piezoelectric Modes 2. Piezoelectric Benders 3. Simple Stack Piezoelectric Transformer 4. Application 1. Basic Piezoelectric Modes 2. Piezoelectric Benders Piezoelectric benders are often used to create actuators with large displacement capabilities. The bender works in a mode which is very similar to the action of a bimetallic spring. Two separate bars or wafers of piezoelectric material are metallized and poled in the thickness expansion mode. They are then assembled in a + -+ - stack and mechanically bonded. 3. Simple Stack Piezoelectric Transformer The figure above shows the basic layout of a stack transformer. The transformer is driven across the lower half (dimension d1) resulting in a thickness mode vibration. This vibration is coupled into the upper half and the output voltage is taken across the thinner dimension d2. 4. Application * * Thickness Expansion Thickness Shear Face Shear Removing the poling electrodes and applying a field perpendicular to the poling direction on a new set of electrodes will result in mechanical shear. Physically shearing the ceramic will produce a voltage on the new electrodes. Ultra-Compact Piezo NanoAutomation Stage with Direct Metrology Miniature Piezo