Piezoelectrically Driven Dispensing Head for Encapsulation of Light Emitting Diode Chip

This study is about an amplified piezoelectric actuator driving a noncontact dispensing head. This dispensing head is mostly used for dispensing silicone encapsulants in a light emitting diode (LED) packaging process. The dispensing head using the piezoelectric actuator is capable of precisely dispensing high-viscosity silicone encapsulants at a high speed. However, the multilayer piezoelectric actuator has a very tiny displacement as small as the order of 10 µm. Accordingly, a device for amplifying the displacement of multilayer piezoelectric actuators is needed. To this end, the authors designed and manufactured a displacement amplification device using a metal frame. The amplification device consists of two multilayer piezoelectric actuators and a metal frame for amplifying displacement. The amplification device has a 209 µm displacement at an input DC voltage of 150 V. The extension displacement and contraction displacement generate 9 and 10 N forces, respectively.

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