| 摘要 |
An optical display image is projected from a projector to a combiner. The combiner includes a front reflection surface, which is in a form of a curved concave surface and forms a front surface virtual image by reflecting the optical display image at a side of the combiner where an inside of a cabin is located, and a back reflection surface, which is in a form of a curved convex surface and forms a back surface virtual image by reflecting the optical display image at another side of the combiner where an outside of the cabin is located. Optical axes, which extend from the front reflection surface and the back reflection surface, respectively, to a predicted eye point of the occupant, are overlapped with each other, and a radius of curvature of the front reflection surface is smaller than a radius of curvature of the back reflection surface. |
| 主权项 |
1. A head-up display device, comprising:
a display member that transmits an external image located at an outside of a cabin of a vehicle to enable visual recognition of the external image by an occupant located in an inside of the cabin; and a projector that projects an optical display image onto the display member to display a virtual image of the optical display image in a manner that enables visual recognition of the virtual image by the occupant, wherein: the display member includes:
a front reflection surface, which is in a form of a curved concave surface and forms a front surface virtual image as the virtual image by reflecting the optical display image at a side of the display member where the inside of the cabin is located; anda back reflection surface, which is in a form of a curved convex surface and forms a back surface virtual image as the virtual image by reflecting the optical display image at another side of the display member where the outside of the cabin is located; an optical axis of the optical display image, which is reflected by the back reflection surface and is outputted from the front reflection surface, and an optical axis of the optical display image, which is reflected by the front reflection surface, are coaxial with each other and extend to a predicted eye point, which is predicted in advance as an eye point of the occupant; and a radius of curvature of the front reflection surface at a reflection point of the front reflection surface, at which the optical axis of the optical display image reflected by the front reflection surface is located, is smaller than a radius of curvature of the back reflection surface at a reflection point of the back reflection surface, at which the optical axis of the optical display image reflected by the back reflection surface is located; a tangent line, which is tangent to the reflection point of the front reflection surface in a cross section of the display member including both of the reflection point of the front reflection surface and the reflection point of the back reflection surface, and a tangent line, which is tangent to the reflection point of the back reflection surface in the cross section of the display member including both of the reflection point of the front reflection surface and the reflection point of the back reflection surface, cross with each other at a predetermined angle; a principal ray, which is projected from an end of the front surface virtual image located at an imaging point of the front surface virtual image to the predicted eye point, is coaxial with a principal ray, which is projected from an end of the back surface virtual image located adjacent to the end of the front surface virtual image at an imaging point of the back surface virtual image to the predicted eye point; and each of the principal ray, which is projected from the end of the front surface virtual image located at the imaging point of the front surface virtual image to the predicted eye point, and the principal ray, which is projected from the end of the back surface virtual image located adjacent to the end of the front surface virtual image at the imaging point of the back surface virtual image to the predicted eye point, define an identical angle relative to both of the optical axis of the optical display image, which is reflected by the back reflection surface and is outputted from the front reflection surface, and the optical axis of the optical display image, which is reflected by the front reflection surface; and the radius of curvature of the back reflection surface is set to form a focal length, which implements a conjugate relationship between the projector and the back surface virtual image while the focal length is obtained based on the following three equations:
1/f′=1/La′+1/Lb′La′=d/{cos(θref−Δθ)·n}+(La−D·sin θi)/cos(θi−θi′)(Lb/La)Lc=(Lb′/La′)/Lc′ where n denotes a refraction index of the display member; Δθ denotes the predetermined angle; θi denotes an incident angle that is measured at the front reflection surface and is of the optical axis of the optical display image, which proceeds from the projector and is incident on the reflection point of the front reflection surface; θi′ denotes an incident angle that is measured at the front reflection surface and is of the optical axis of the optical display image, which proceeds from the projector and is incident on the reflection point of the back reflection surface; θref denotes a reflection angle of the optical axis of the optical display image at the reflection point of the back reflection surface; La denotes a distance from the projector to the reflection point of the front reflection surface; La′ denotes an air conversion length from the projector to the reflection point of the back reflection surface through a refraction point of the front reflection surface along the optical axis of the optical display image, which is outputted from the refraction point of the front reflection surface to the reflection point of the back reflection surface; Lb denotes a length from the reflection point of the front reflection surface to the imaging point of the front surface virtual image; Lb′ denotes an air conversion length that is obtained by subtracting a value, which is obtained by dividing a distance between the reflection point of the front reflection surface and the reflection point of the back reflection surface by the refraction index, from a distance from the reflection point of the front reflection surface to the imaging point of the back surface virtual image; Lc denotes a length from the imaging point of the front surface virtual image to the predicted eye point; Lc′ denotes a length from the imaging point of the back surface virtual image to the predicted eve point; D denotes a distance between the refraction point of the front reflection surface and the reflection point of the front reflection surface; and d denotes a distance between a perpendicular point of the front reflection surface, which is perpendicular from the reflection point of the back reflection surface, and the reflection point of the back reflection surface; and f′ denotes the focal length for implementing the conjugate relationship between the projector and the back surface virtual image. |
