High density multi-channel array, electrically pulsed droplet deposition apparatus.

摘要

A high density multi-channel array, electrically pulsed droplet deposition apparatus comprises a sheet (14) of piezoelectric material poled in a direction normal to said sheet and formed with a plurality of parallel channels (12) mutually spaced in an array direction normal to the length of said channels. Each channel is defined by a pair of facing side walls (16) and a bottom surface (18) extending between the respective side walls (16). A top sheet (20) facing said bottom surfaces of said channels and bonded to said side walls closes the channels at their tops. Each of the channels is further formed with a forward part of uniform depth between the bottom surface and the top sheet and a part rearwardly of the forward part of lesser depth than the forward part. Each of at least some of the side walls of the forward parts include electrodes (34) on opposite sides thereof to form shear mode actuators for effecting droplet expulsion from the channels associated with the actuators. Each electrode extends substantially along the length of the corresponding side wall and over an area from the edge of the side wall adjoining the top sheet which is so spaced from the bottom surface of the channel in which the electrode (34) is disposed as to leave the portion of the wall adjacent the bottom surface of the channel substantially free from elastic distortion when an electric field is applied across the electrodes of the associated wall.