High density electrical interconnect for printing devices using flex circuits and dielectric underfill

摘要

A method for forming an ink jet print head can include attaching a plurality of piezoelectric elements to a diaphragm of a jet stack subassembly, electrically attaching a flex circuit to the plurality of piezoelectric elements, then dispensing an dielectric underfill between the flex circuit and the jet stack subassembly. The use of an underfill after attachment of the flex circuit eliminates the need for the patterned removal of an interstitial material from the tops of the piezoelectric elements, and removes the requirement for a patterned standoff layer. In an embodiment, electrical contact between the flex circuit and the piezoelectric elements is established through physical contact between bump electrodes of the flex circuit and the piezoelectric elements, without the use of a separate conductor, thereby eliminating the possibility of electrical shorts caused by misapplication of a conductor.