Head-up display device

1. A head-up display device for allowing a viewer on a vehicle to visually recognize a virtual image in a virtual image display region, the head-up display device comprising:

a display unit including a display surface emitting display light that is a source of the virtual image; and

a relay optical system configured to relay the display light emitted by the display surface toward a projected unit to maintain at least a part of the virtual image display region to be below a road surface on which the vehicle travels.

2. The head-up display device according to claim 1 , comprising the display unit configured in such a manner that the display surface is positioned to be tilted with respect to an optical axis of the display light directed toward the viewer in a direction in which the virtual image display region is along a front-rear direction of the vehicle.

3. The head-up display device according to claim 1 , wherein a far end of the virtual image display region seen from the viewer in a front-rear direction of the vehicle is positioned at a highest position of the virtual image display region.

4. The head-up display device according to claim 1 , comprising the virtual image display region configured in such a manner that a far end seen from the viewer in a front-rear direction of the vehicle is positioned above the road surface, and a near end seen from the viewer in the front-rear direction of the vehicle is positioned below the road surface.

5. The head-up display device according to claim 3 , comprising the virtual image display region configured in such a manner that an angle of a tangent line with respect to the front-rear direction of the vehicle broadly monotonously increases from a vicinity of the viewer toward a far side.

6. The head-up display device according to claim 1 , wherein a far end of the virtual image display region seen from the viewer in a front-rear direction of the vehicle is positioned at a lowest position of the virtual image display region.

7. The head-up display device according to claim 1 , comprising the virtual image display region configured in such a manner that a far end seen from the viewer in a front-rear direction of the vehicle is positioned below the road surface, and a near end seen from the viewer in the front-rear direction of the vehicle is positioned above the road surface.

8. The head-up display device according to claim 6 , comprising the virtual image display region configured in such a manner that an angle of a tangent line with respect to the front-rear direction of the vehicle broadly monotonously increases from a vicinity of the viewer toward a far side.

9. The head-up display device according to claim 1 , wherein a middle region between a far end and a near end of the virtual image display region seen from the viewer in a front-rear direction of the vehicle is positioned at a lowest position of the virtual image display region.

10. The head-up display device according to claim 9 , comprising the virtual image display region configured in such a manner that the far end or/and the near end are positioned above the road surface.

11. The head-up display device according to claim 1 , further comprising:

one or more actuators configured to move or/and rotate the display surface or/and the relay optical system;

one or more I/O interfaces;

one or more processors;

a memory; and

one or more computer programs stored in the memory and configured to be executed by the one or more processors,

wherein the one or more processors are configured to execute an instruction to acquire a position of the road surface and to drive the actuators in such a manner that at least a part of the virtual image display region is positioned below the road surface on a basis of the position of the road surface.

12. A head-up display device for allowing a viewer on a vehicle to visually recognize a virtual image in a virtual image display region, the head-up display device comprising:

a display unit including a display surface emitting display light that is a source of the virtual image; and

a relay optical system configured in such a manner that the display light emitted by the display surface is relayed toward a projected unit, and that at least a part of the virtual image display region is positioned below a road surface on which the vehicle travels,

wherein the virtual image display region is configured to be in a curved shape in such a manner that an angle of a tangent line with respect to a front-rear direction of the vehicle broadly monotonously increases from a vicinity of the viewer toward a far side of the viewer.

13. The head-up display device according to claim 12 , wherein a far end of the virtual image display region seen from the viewer in the front-rear direction of the vehicle is positioned at a highest position of the virtual image display region.

14. A head-up display device for allowing a viewer on a vehicle to visually recognize a virtual image in a virtual image display region, the head-up display device comprising:

a display unit including a display surface emitting display light that is a source of the virtual image; and

a relay optical system configured in such a manner that the display light emitted by the display surface is relayed toward a projected unit, and that at least a part of the virtual image display region is positioned below a road surface on which the vehicle travels,

wherein the virtual image display region comprises i) a far end and ii) a near end positioned closer to the vehicle than the far end, and

wherein the near end of the virtual image display region is positioned at eight meters in front of the vehicle.