TECHNICAL FIELD

The present invention relates to an information display apparatus that projects images on a windshield glass of so-called vehicle such as a car, a train and an airplane, that moves while people are loaded therein.

BACKGROUND ART

So-called head-up-display (HUD) apparatus has been already known in, for example, the following Patent Document 1, the head-up-display apparatus creating virtual images by projecting image light onto a windshield glass of a car to display traffic information such as route information and traffic jam information and car information such as a fuel level and a coolant temperature.

Such a type of the information display apparatus is desirable to be downsized since the HUD apparatus itself is arranged between a windshield glass and a steering in front of a driver seat.

RELATED ART DOCUMENT

Patent Document

Patent Document 1: Japanese Patent Application Laid-Open Publication No. 2015-194707

SUMMARY OF THE INVENTION

Problems to be Solved by the Invention

In a principle of the virtual image creation using a concave mirror for achieving a head-up-display apparatus according to a related art, a virtual image using a concave mirror1′ is acquired by arranging object points A and B on portions that are inside a focal point “F” (focal length “f”) from a point 0 on an optical axis of the concave mirror1′ as shown inFIG. 22. InFIG. 22, the concave mirror1′ is regarded as a convex lens having a similar positive refractive power for convenience of description, and a relation among the object points, the convex lens (described as the concave mirror inFIG. 20for convenience of description) and the created virtual image is shown.

In a related art, in order to increase a size of the virtual image created by the concave mirror1′, it is better to bring the object points A and B to be close to the focal point F. However, in order to acquire a desirable magnification, a curvature radius of the concave mirror is reduced. As a result, the mirror size becomes small, and therefore, only a virtual image having a large magnifying power but a small viewable range is consequently practically acquired. Therefore, in order to satisfy both (1) the desirable virtual image size and (2) the necessary virtual-image magnification “M=b/a” at the same time, it is necessary to fit the concave mirror dimension with the viewable range, and to determine the virtual-image magnification balanced with the image display apparatus.

On the other hand, in the HUD of the virtual image mode disclosed in the Patent Document 1, in order to increase a dimension of the virtual image that can be viewed by a viewer, a volume of the apparatus increases because the concave mirror dimension creating the virtual mage is large.

In the Patent Document 1, an HUD that displays a virtual image of information such as so-called speed information is described, but so-called augmented reality is not taken into consideration, the augmented reality enlarging the virtual-image viewable range that can be visually recognized by the viewer, enlarging the virtual image size, and overlapping the virtual image with a practical image of a background view looked at by eyes of the viewer. In order to achieve the augmented reality, it is necessary to increase a distance from an image source to the concave mirror. And, when a case of overlap of the virtual image with a practical image of a foreground view is also taken into consideration, point-of-view motion becomes small and unnatural, and therefore, it is necessary to consider an image display apparatus capable of acquiring a lot of pieces of the image information while improving this unnaturalness.

Accordingly, a purpose of the present invention is to provide an image display apparatus capable of causing smoother (more natural) point-of-view motion of a viewer to reduce the motion and acquiring a lot of pieces of image information.

Means for Solving the Problems

The present invention has been made in consideration of the above-described background art and problem. As one example to be cited, in an information display apparatus displaying image information onto a vehicle, the information display apparatus includes a first information display apparatus and a second information display apparatus arranged between a windshield of the vehicle and an instrument panel of the vehicle, the instrument panel includes a direct-view type image display apparatus, the first information display apparatus includes a virtual-image optical system that displays a virtual image onto a forward part of the vehicle by causing the windshield glass to reflect light emitted from the image display apparatus displaying the image information, and the second information display apparatus includes a practical-image optical system that projects light to acquire a practical image overlapped with the virtual image created by the first information display apparatus.

Effects of the Invention

The above-described present invention can provide an information display apparatus reducing point-of-view motion of a driver to contribute to safety driving assistance by display combination among a HUD apparatus that overlaps a virtual image with a background view, a practical-image display apparatus that displays a practical image overlapped with a foreground view, and an instrument panel.

