Spray ejector mechanisms and devices providing charge isolation and controllable droplet charge, and low dosage volume ophthalmic administration

A charge isolated ejector mechanism for generating droplets of a fluid comprising:

• a flexible printed circuit comprising a laminate structure including:
• (a) a generator plate having a fluid entrance side, a droplet exit side, and a plurality of openings formed through its thickness;
• (b) a piezoelectric actuator operable to directly or indirectly oscillate the generator plate upon application of a voltage;
• (c) a first conducting layer having a top surface opposite a bottom surface;
• (d) a dielectric layer having a top surface opposite a bottom surface;
• and
• (e) a second conducting layer having a top surface opposite a bottom surface;
• wherein:
• at least a portion of the top surface of the first conducting layer faces the piezoelectric actuator and at least a portion of the bottom surface of the first conducting layer faces at least a portion of the top surface of the dielectric layer to separate the piezoelectric actuator from the dielectric layer;
• at least a portion of the bottom surface of the dielectric layer faces the top surface of the second conducting layer to separate the first conducting layer from the second conducting layer;
• and
• at least a portion of the bottom surface of the second conducting layer faces the fluid entrance side of the generator plate to separate the dielectric layer from the generator plate;
• thereby charge isolating and grounding the generator plate.