Droplet emitting apparatus having piezoelectric voltage generator and method of emitting a droplet using the same

A droplet emitting apparatus using electrohydrodynamics comprising:

• a solution tank for containing a solution;
• a nozzle comprising an opening through which at least a droplet of the solution is emitted;
• a voltage generator for generating a voltage by applying instantaneous pressure to a piezoelectric material, wherein the voltage generated by the pressure to the piezoelectric material is applied to the solution through an electrode in order for the at least a droplet of the solution to be emitted through the opening of the nozzle to a target object by an electrical attraction between the solution and the target object;
• a target mounting portion on which the target object onto which the solution emitted is disposed to face the nozzle;
• and
• a distance adjusting unit for reciprocating the target object between a first position at which the target object is relatively close to the nozzle and a second position at which the target object is relatively far from the nozzle,
• wherein, when the target object is in the first position, distance between the target object and the front end of the nozzle is less than a critical distance which is the maximum distance at which a liquid bridge is formed between the target object and the front end of the nozzle due to the voltage applied to the solution, and when the target object is in the second position, the distance between the target object and the front end of the nozzle is the same as or greater than a distance at which the liquid bridge breaks up.