In-vehicle input unit

1. An in-vehicle input unit, comprising:

a head-up display which projects a hierarchical menu for operating a plurality of pieces of in-vehicle equipment onto a windshield in front of a driver's seat, and displays the hierarchical menu as a virtual image ahead of the windshield;

a plurality of switches disposed in a steering wheel so that several switches adjoin and surround one central switch; and

a changing switch which is disposed in the steering wheel and accepts a default instruction for displaying on the head-up display a default operation menu having default selection items for operating the in-vehicle equipment directly without using the hierarchical menu,

wherein the head-up display displays selection items on the hierarchical menu as the virtual image so that the selection items correspond one to one to the plurality of switches disposed in the steering wheel; and

if the changing switch accepts the default instruction, the head-up display displays the default selection items on the default operation menu as the virtual image so that the default selection items correspond one to one to the plurality of switches.

2. The in-vehicle input unit according to claim 1 , wherein the central switch is different in height from the other adjoining and surrounding switches.

3. The in-vehicle input unit according to claim 1 , wherein the central switch has a concave portion or a convex portion.

4. The in-vehicle input unit according to claim 1 , wherein in the top layer of the hierarchical menu, the plurality of pieces of in-vehicle equipment are set as selection items.

5. The in-vehicle input unit according to claim 1 , wherein:

the plurality of pieces of in-vehicle equipment include an audio apparatus; and

the default operation menu includes a selection item for accepting an instruction to increase the sound volume of the audio apparatus, and a selection item for accepting an instruction to decrease the sound volume of the audio apparatus.

6. The in-vehicle input unit according to claim 5 , wherein:

the audio apparatus is a radio receiver; and

the default operation menu further includes a selection item for accepting an instruction to select a broadcasting station.

7. The in-vehicle input unit according to claim 1 , wherein:

the plurality of pieces of in-vehicle equipment include a plurality of kinds of audio apparatuses; and

the default operation menu includes selection items for accepting an instruction to select one from the plurality of kinds of audio apparatuses.

8. The in-vehicle input unit according to claim 1 , wherein:

the plurality of pieces of in-vehicle equipment include an air-conditioning apparatus; and

the default operation menu includes selection items for turning on the power of the air-conditioning apparatus.

9. The in-vehicle input unit according to claim 1 , wherein:

the plurality of pieces of in-vehicle equipment include a car-navigation apparatus; and

the default operation menu includes a selection item for allowing the car-navigation apparatus to give information about where a vehicle is located at present.

10. The in-vehicle input unit according to claim 1 , wherein the plurality of switches are disposed so that six switches adjoin and surround the central switch.

11. The in-vehicle input unit according to claim 10 , wherein as the plurality of switches, two on the forward side, two on the backward side, one on the left side and one on the right side from the central switch are disposed when the steering wheel is positioned so that the vehicle runs straight.

12. The in-vehicle input unit according to claim 1 , wherein the plurality of switches are different in shape from the changing switch.

13. An in-vehicle input unit, comprising:

a head-up display which projects a hierarchical menu for operating a plurality of pieces of in-vehicle equipment onto a windshield in front of a driver's seat, and displays the hierarchical menu as a virtual image ahead of the windshield;

a plurality of switches disposed in a steering wheel so that several switches adjoin and surround one central switch; and

a top-menu switch which accepts a top-menu instruction for displaying the top layer of the hierarchical menu,

wherein the head-up display displays selection items on the hierarchical menu as the virtual image so that the selection items correspond one to one to the plurality of switches disposed in the steering wheel; and

if the top-menu switch accepts the top-menu instruction, the head-up display displays the top layer of the hierarchical menu as the virtual image.

14. The in-vehicle input unit according to claim 13 , wherein:

the steering wheel includes two spokes;

the plurality of switches are disposed in one of the spokes; and

the top-menu switch is disposed in the other of the spokes.

15. The in-vehicle input unit according to claim 14 , wherein the spokes are disposed in the horizontal direction of the steering wheel positioned so that a vehicle runs straight.

16. The in-vehicle input unit according to claim 15 , wherein:

one of the spokes is disposed on the left hand of the steering wheel; and

the other spoke is disposed on the right direction of the steering wheel.

17. The in-vehicle input unit according to claim 13 , wherein the central switch is different in height from the other adjoining and surrounding switches.

18. The in-vehicle input unit according to claim 13 , wherein the central switch has a concave portion or a convex portion.

19. The in-vehicle input unit according to claim 13 , wherein in the top layer of the hierarchical menu, the plurality of pieces of in-vehicle equipment are set as selection items.

20. The in-vehicle input unit according to claim 13 , wherein the plurality of switches are disposed so that six switches adjoin and surround the central switch.

21. An in-vehicle input unit, comprising:

a head-up display which projects a hierarchical menu for operating a plurality of pieces of in-vehicle equipment onto a windshield in front of a driver's seat, and displays the hierarchical menu as a virtual image ahead of the windshield;

a plurality of switches disposed in a steering wheel so that several switches adjoin and surround one central switch; and

a return switch which accepts a return instruction for displaying a virtual image displayed one frame ahead by the head-up display,

wherein the head-up display displays selection items on the hierarchical menu as the virtual image so that the selection items correspond one to one to the plurality of switches disposed in the steering wheel; and

if the return switch accepts the return instruction, the head-up display displays the virtual image displayed one frame ahead.

22. The in-vehicle input unit according to claim 21 , wherein:

the steering wheel includes two spokes;

the plurality of switches are disposed in one of the spokes; and

the return switch is disposed in the other of the spokes.

23. The in-vehicle input unit according to claim 21 , wherein the central switch is different in height from the other adjoining and surrounding switches.

24. The in-vehicle input unit according to claim 21 , wherein the central switch has a concave portion or a convex portion.

25. The in-vehicle input unit according to claim 21 , wherein in the top layer of the hierarchical menu, the plurality of pieces of in-vehicle equipment are set as selection items.

26. The in-vehicle input unit according to claim 21 , wherein the plurality of switches are disposed so that six switches adjoin and surround the central switch.