HEAD-UP DISPLAY APPARATUS

• US 20130021224A1
• Filed: 07/18/2012
• Published: 01/24/2013
• Est. Priority Date: 07/24/2011
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Fujikawa, Takayuki, Fukasawa, Kazuto, Imahori, Hideaki
• Granted Patent: US 8,766,879 B2
• Time in Patent Office: Days
• US Class Current: 345/7
• CPC Class Codes: G02B 2027/011 comprising device for correcting geometrical aberrations, distortion
• CPC Class Codes: G02B 27/0101 characterised by optical features G02B27/0172 takes precedence

Abstract

A display image to be projected onto a projection surface is formed on an imaging surface of a screen member at time of projecting the display image onto the projection surface. A projector is adapted to project a light, which forms the display image on the imaging surface. The imaging surface is formed as a convex surface that limits a curvature of field of the virtual image.

Claims

1. A head-up display apparatus, which is adapted to project a display image onto a projection surface of a display member to enable a viewer to view a virtual image of the display image from a predetermined viewing area, the head-up display apparatus comprising:

a screen member that includes an imaging surface, on which the display image to be projected onto the projection surface is formed at time of projecting the display image onto the projection surface; and

a projector that is adapted to project a light, which forms the display image on the imaging surface, wherein the imaging surface is formed as a convex surface that limits a curvature of field of the virtual image.

2. The head-up display apparatus according to claim 1, wherein:

the projection surface is formed as a concave surface; and

the imaging surface is formed as the convex surface that limits the curvature of field of the virtual image, which is caused by a curvature of the projection surface.

3. The head-up display apparatus according to claim 1, wherein the projection surface is formed as a concave surface, which is curved and is recessed in a direction away from the predetermined viewing area.

4. The head-up display apparatus according to claim 1, wherein the imaging surface is curved and is protruded toward the projector.

5. The head-up display apparatus according to claim 1, wherein the imaging surface is three-dimensionally curved in both of a first direction and a second direction, which are perpendicular to each other, based on a curvature of the projection surface in the first direction and a curvature of the projection surface in the second direction.

6. The head-up display apparatus according to claim 1, further comprising a magnifying mirror that includes a reflection surface, which is formed as a concave surface and projects the display image onto the projection surface at time of projecting the display image onto the projection surface by reflecting the display image formed on the imaging surface upon enlarging the display image by the reflection surface, wherein the imaging surface is formed as the convex surface that limits the curvature of field of the virtual image, which is caused by a curvature of the reflection surface.

7. The head-up display apparatus according to claim 6, wherein the reflection surface is curved and is recessed in a direction away from the imaging surface.

8. The head-up display apparatus according to claim 6, wherein the reflection surface is three-dimensionally curved in both of a first direction and a second direction, which are perpendicular to each other, based on a curvature of the projection surface in the first direction and a curvature of the projection surface in the second direction.

9. The head-up display apparatus according to claim 6, wherein:

the display image projected onto the display member is elongated in a first direction rather than a second direction of the display image, which is perpendicular to the first direction;

the reflection surface is formed as the concave surface, which enlarges the display image projected onto the display member such that a magnification of the display image in the first direction is larger than a magnification of the display image in the second direction; and

the imaging surface is formed as the convex surface, which is more curved in the first direction than the second direction to limit the curvature of field of the virtual image in the first direction.

10. The head-up display apparatus according to claim 1, further comprising a focusing point adjusting optical system that adjusts a focusing point, in which the light projected from the projector is focused, to place the focusing point on the imaging surface.

11. The head-up display apparatus according to claim 10, wherein the focusing point adjusting optical system includes a free-form-surface optical element that has one of a light input surface and a light output surface, which has a curved surface section that is defined by a polynomial having an odd-order term.

12. The head-up display apparatus according to claim 1, wherein:

the projector is adapted to project a laser light as the light; and

the projector scans the laser light on the imaging surface to form the display image on the imaging surface.

13. The head-up display apparatus according to claim 1, wherein:

the head-up display apparatus is for a vehicle; and

the projection surface of the display member is one of;

a surface of a windshield of the vehicle; and

a surface of a separate member that is formed separately from the windshield and is placed adjacent to an interior surface of the windshield.