Mems-based Piezoelectric Micro Jet Developed

As an important actuator in the micro fluidic system , the micro jet could eject many kinds of substances (ink , polymer , solid) . It could realize DNA microarray , minim reagent supply , micro propulsion and ink jet printing . The devices have a wonderful application future in the medical , biological and chemical fields.The theoretical model of shear mode micro jet is established and the edge displacement under dynamic driving voltage is analyzed . The geometrical parameters of the micro jet are optimized by finite element analysis and the modal of vibration is simulated . A special driving power , which can drive micro jet array , is developed and the speed of charge or discharge is very fast . The structure of the micro jet , which works in the pure shear mode , is improved upon by introducing mechanical plus and consequently the driving ability is heightened .The sub-nano litre level shear mode piezoelectric micro jet is developed and tested . The optimal structure , process flow , technical parameters are explored and the stability as well as the rate of finished product are improved . The driving method is also studied and we lay good foundation of the application of piezoelectric micro jet interiorly . The droplet produced by the micro jet is sub-nano litre in volume and the micro jet can eject droplets in series . The volume and the amount of the droplets are controlled by the driving pulse . Applying one driving pulse , the micro jet ejects one droplet and it is easy to form one dimensional micro jet array .The problem of how to connect the electrode on the cliff side of the actuating wall , when the electric field is applied perpendicular to the poling direction , is solved . By the transition of middle layer , metal form a low vestige stress layer on the surface of the piezoelectric ceramics . The compatibility of different techniques is improved .