Head unit

1. A head unit comprising:

a first substrate provided with a first terminal and a second terminal;

a second substrate 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 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 a 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 which is positioned between the second substrate and the third substrate, and supplies a liquid to the first driving module and the second driving module,

wherein the first substrate is positioned on the second substrate side in a direction intersecting with a direction in which a liquid is discharged from the first nozzle or the second nozzle.

2. The head unit according to claim 1 ,

wherein at least one side of the first substrate is positioned so as to overlap at least one side of the second substrate in the direction in which the liquid is discharged from the first nozzle or the second nozzle.

3. The head unit according to claim 1 ,

wherein the liquid flow passage is positioned further on the third substrate side than the first substrate in the direction intersecting with the direction in which the liquid is discharged from the first nozzle or the second nozzle.

4. The head unit according to claim 1 ,

wherein a part of the first flexible wiring substrate is positioned between the second substrate and the liquid flow passage.

5. The head unit according to claim 1 ,

wherein a part of the second flexible wiring substrate is positioned between the third substrate and the liquid flow passage.

6. The head unit according to claim 1 , further comprising:

a fifth terminal provided in the second substrate;

a fourth substrate provided with a sixth terminal; and

a third flexible wiring substrate that connects the fifth terminal and the sixth terminal to each other.

7. The head unit according to claim 6 ,

wherein a part of the third flexible wiring substrate is positioned between the fourth substrate and the liquid flow passage.

8. The head unit according to claim 6 ,

wherein, in the direction in which the liquid is discharged from the first nozzle or the second nozzle, a distance between the first substrate and the second substrate is greater than a distance between the second substrate and the fourth substrate, and the distance between the second substrate and the fourth substrate is greater than a distance between the first driving module and the fourth substrate.

9. The head unit according to claim 6 , further comprising:

a seventh terminal provided in the third substrate;

a fifth substrate provided with an eighth terminal; and

a fourth flexible wiring substrate that connects the seventh terminal and the eighth terminal to each other.

10. The head unit according to claim 9 ,

wherein a part of the fourth flexible wiring substrate is positioned between the fifth substrate and the liquid flow passage.

11. The head unit according to claim 9 ,

wherein a difference between a distance between the second substrate and the fourth substrate and a distance between the third substrate and the fifth substrate is greater than a difference between a distance between the fourth substrate and the first driving module and a distance between the fifth substrate and the second driving module, and

wherein a difference between a distance between the first substrate and the second substrate and a distance between the first substrate and the third substrate is greater than a difference between the distance between the second substrate and the fourth substrate and the distance between the third substrate and the fifth substrate.

12. The head unit according to claim 9 ,

wherein the first substrate has a ninth terminal and transfers a driving signal for displacing at least one of the first piezoelectric element and the second piezoelectric element and a control signal for controlling the driving signal, from the ninth terminal to the first terminal and the second terminal.

13. The head unit according to claim 12 ,

wherein the driving signal and the control signal are transferred to the second substrate and the third substrate.

14. The head unit according to claim 12 ,

wherein the driving signal and the control signal are transferred to the fourth substrate and the fifth substrate.

15. The head unit according to claim 9 ,

wherein one or a plurality of each of the second substrate, the third substrate, the fourth substrate, and the fifth substrate are provided,

wherein the total number of the second substrates and the third substrates is greater than the number of the first substrates, and

wherein the total number of the fourth substrates and the fifth substrates is greater than the total number of the second substrates and the third substrates.

16. The head unit according to according to claim 9 , further comprising:

an outer wall portion that surrounds the second substrate and the first flexible wiring substrate,

wherein a distance between the second substrate and the outer wall portion is smaller than a distance between the first flexible wiring substrate and the outer wall portion.

17. The head unit according to claim 16 ,

wherein the outer wall portion surrounds the third substrate and the second flexible wiring substrate, and

wherein a distance between the third substrate and the outer wall portion is smaller than a distance between the second flexible wiring substrate and the outer wall portion.

18. The head unit according to claim 16 ,

wherein the outer wall portion surrounds the fourth substrate and the third flexible wiring substrate, and

wherein a distance between the fourth substrate and the outer wall portion is smaller than a distance between the third flexible wiring substrate and the outer wall portion.

19. The head unit according to claim 16 ,

wherein the outer wall portion surrounds the fifth substrate and the fourth flexible wiring substrate, and

wherein a distance between the fifth substrate and the outer wall portion is smaller than a distance between the fourth flexible wiring substrate and the outer wall portion.