Head unit

A head unit comprising:

• a first substrate including a first surface provided with a first terminal and a second surface provided with a second terminal;
• a second substrate including a third surface provided with a third terminal;
• a first flexible wiring substrate that connects the first terminal and the third terminal to each other;
• a first driving module that includes a plurality of first piezoelectric elements, a plurality of first cavities which are associated with the plurality of first piezoelectric elements and of which an internal volume changes due to displacement of the associated first piezoelectric elements, and a plurality of first nozzles which are associated with the plurality of first cavities, which discharge a liquid corresponding to the change in the internal volume of the associated first cavities, and of which the provided number is 600 or more with a density of 300 or more per one inch, and is electrically connected to the second substrate;
• a third substrate including a fourth surface provided with a fourth terminal;
• a second flexible wiring substrate that connects the second terminal and the fourth terminal to each other;
• a second driving module that includes a plurality of second piezoelectric elements, a plurality of second cavities which are associated with the plurality of second piezoelectric elements and of which an internal volume changes due to displacement of the associated second piezoelectric elements, and a plurality of second nozzles which are associated with the plurality of second cavities, which discharge the liquid corresponding to the change in the internal volume of the associated second cavities, and of which the provided number is 600 or more with a density of 300 or more per one inch, and is electrically connected to the third substrate;
• and
• a liquid flow passage through which the liquid is supplied to the first driving module and the second driving module,
• wherein the first surface, the second surface, the third surface, and the fourth surface are respectively positioned along a direction in which the liquid is discharged from the first nozzle or the second nozzle, and
• wherein the liquid flow passage is positioned between the second substrate and the third substrate.