JPH08192664A - Head up display device - Google Patents

Abstract

PURPOSE: To provide a head up display device which can display a good hologram image by small-sized simple constitution, and in addition can favorably display a relative large optical image as a hologram image by such constitution. CONSTITUTION: An optical image generating means 3 is arranged opposite to a hologram combiner 1 so that the optical path of the optical image from the optical image generating means 3 to the hologram combiner 1 is a straight line, and a Fresnel lens 4 is arranged on the optical path of the optical image between the optical image generating means 3 and the hologram combiner 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a head-up display device used in automobiles and the like.

[0002]

2. Description of the Related Art A head-up display device of this type is for displaying an image showing vehicle speed, road information, etc. in front of the windshield of an automobile by using a hologram. A hologram image is displayed in front of the windshield by projecting an optical image of a predetermined wavelength from a CRT display or a liquid crystal display onto the attached hologram combiner. In this case, it is necessary to increase the depth (depth) of the hologram image displayed in front of the windshield to some extent, and particularly in an automobile or the like, dispose the display on the dashboard or the like with a large distance from the hologram combiner. However, it is known that the optical image generated by the display is magnified by using a concave mirror and projected on a hologram combiner as shown in FIG. 2, for example.

That is, in the head-up display device shown in FIG. 2, a concave mirror c is arranged below a hologram combiner b attached to a windshield a, and a light is emitted from a display d to the concave mirror c via a plane mirror e. The image is projected, enlarged by the concave mirror c, and projected on the hologram combiner b.

As described above, by enlarging the light image generated by the display d and projecting it on the hologram combiner b, the position where the apparent light image (virtual image) is generated from the hologram combiner b is the hologram. The distance from the combiner b increases, and the depth of the hologram image generated by the hologram combiner b increases.

However, such a head-up display device has the following inconveniences.

That is, in the head-up display device, the display d is displayed on the optical axis of the concave mirror c.
Cannot be arranged, and therefore the optical image generated by the display d must be incident on the concave mirror c by inclining it with respect to the optical axis of the concave mirror c. Therefore, the optical image magnified and reflected by the concave mirror c is likely to be distorted, and as a result, the hologram image finally obtained is also distorted. Further, since the display d cannot be arranged on the optical axis of the concave mirror c, a relatively large space for installing them is required. Therefore, particularly in an automobile or the like, the concave mirror c and the concave mirror c cannot be arranged. It becomes difficult to install the display d in a narrow space such as a dashboard.

Further, when a relatively large optical image such as a map is generated on the display d and is displayed as a hologram image, it is necessary to increase the diameter of the concave mirror c. The large concave mirror c of
Its focal length also becomes longer. Therefore, following this,
The optical path length of the optical image from the display d to the concave mirror c must be lengthened, the installation space required for them must be further increased, the size of the device must be increased, and it must be installed in an automobile or the like. It may be impossible.

[0008]

DISCLOSURE OF THE INVENTION The present invention eliminates such inconveniences and enables a good hologram image to be displayed with a small and simple structure, and a relatively large optical image can be used as a hologram image with such a structure. It is an object of the present invention to provide a head-up display device capable of excellent display.

[0009]

In order to achieve such an object, the present invention provides a hologram combiner provided in a visual field of a viewer and an optical image producing means for producing an optical image to be projected on the hologram combiner. And an optical image magnifying means which is provided on the optical path of the optical image from the optical image generating means to the hologram combiner and which magnifies and projects the optical image generated by the optical image generating means onto the hologram combiner. In a head-up display device including the optical image generating means, the optical image generating means is arranged to face the hologram combiner so that the optical path of the optical image from the optical image generating means to the hologram combiner is linear, and the optical image enlargement is performed. The means is constituted by a Fresnel lens, and the Fresnel lens is composed of the optical image generating means and the hologram combiner. In characterized by being arranged on an optical path of the light image.

Further, the optical image generating means or the Fresnel lens is provided so as to be movable in the optical path direction.

Further, the hologram combiner is attached to a windshield in front of a viewer.

[0012]

According to the present invention, the optical image generating means and the Fresnel lens are linearly arranged toward the hologram combiner. In this case, the Fresnel lens can be made relatively thin and have a short focal length even if the aperture is made large, whereby the distance between the optical image generating means and the Fresnel lens is relatively short. At the same time, it becomes possible to appropriately magnify the optical image generated by the optical image generating means and project it onto the hologram combiner. Further, even if the Fresnel lens has a large aperture, it is possible to magnify an optical image in a state where there is little distortion in each part, and a relatively large optical image is sharply magnified and projected onto the hologram combiner. It becomes possible.

Therefore, according to the present invention, even if the optical image produced by the optical image producing means is relatively large, the distance between the optical image producing means and the Fresnel lens can be made short and the optical image producing means can be used. The Fresnel lens and the Fresnel lens can be arranged linearly toward the hologram combiner.

Further, when the optical image generating means or the Fresnel lens is provided so as to be movable in the optical path direction, by moving the optical image generating means or the Fresnel lens, the holographic combiner finally allows the viewer to see the visual field. It is possible to appropriately adjust the depth of the hologram image displayed in the front.

Further, when the hologram combiner is attached to the windshield in front of the viewer, the depth of the hologram image can be deepened by giving the windshield a function as a lens.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One example of the present invention will be described with reference to FIG. FIG. 1 is an explanatory side view showing the configuration of the head-up display device of this embodiment.

Referring to FIG. 1, the head-up display device of this embodiment is installed in, for example, an automobile A, and 1 is a driver's visual field and is attached to a windshield 2 along its surface shape. A hologram combiner worn,
Reference numeral 3 is an optical image generating means for generating an optical image to be displayed, and 4 is a Fresnel lens as an optical image enlarging means for enlarging the optical image generated by the optical image generating means 3 and projecting it on the hologram combiner 1.

The optical image generating means 3 includes a light source 7 housed in a recess 6 formed directly below the hologram combiner 1 and in front of the driver's seat on the upper surface of the dashboard 5 so as to face the hologram combiner 1, and the light source 7 thereof. The liquid crystal shutter 8 is housed in the recess 6 above. The liquid crystal shutter 8 generates an image to be displayed, such as road information and a map, according to an instruction from a microcomputer (not shown), receives the light from the light source 7, and converts it into an optical image of a predetermined wavelength from the inside of the recess 6 to form a hologram combiner. Light is projected linearly toward 2.

The Fresnel lens 4 has a shape in which annular lenses are concentrically arranged, and is arranged between the hologram combiner 1 and the liquid crystal shutter 8 on a linear optical path from the liquid crystal shutter 8 to the hologram combiner 1. It is loaded in the upper part of the recess 6. In this case, the Fresnel lens 4 has a relatively large aperture so that a relatively large optical image generated by the liquid crystal shutter 8 can be enlarged and projected onto the hologram combiner 1, but its focus is large. Since the distance is short, the liquid crystal shutter 8 and the Fresnel lens 4 are arranged relatively close to each other.

The Fresnel lens 4 is moved up and down on the optical path from the liquid crystal shutter 8 to the hologram combiner 1 in the recess 6 by an elevating mechanism 9 composed of a motor or the like provided on the side of the Fresnel lens 4. You can move to. The movement of the Fresnel lens 4 is appropriately performed by, for example, an instruction from a microcomputer (not shown) or an instruction from a driver.

Next, the operation of the apparatus of this embodiment will be described.

The image of road information or a map generated by the liquid crystal shutter 8 is projected as an optical image toward the hologram combiner 1 by the light emitted from the light source 7. At this time, as indicated by the solid arrow in FIG. 1, the optical image is enlarged by the Fresnel lens 4 and projected onto the hologram combiner 1, and is further reflected by the hologram combiner 1 toward the eyes of the driver. To be done. The optical image received by the driver from the hologram combiner 1 is, as seen from the driver, a windshield 2 as shown by a dashed line in FIG.
A virtual image is formed in front of, for example, a position indicated by a point P, and an optical image generated by the liquid crystal shutter 8 is apparently displayed as a hologram image at a position of the point P.

In this case, by appropriately moving the Fresnel lens 4 up and down via the elevating mechanism 9 according to a microcomputer or a driver's instruction, the depth of the hologram image seen by the driver is adjusted to an appropriate depth. It

In such a head-up display device, even if the optical image generated by the liquid crystal shutter 8 is relatively large, the Fresnel lens 4 has a large aperture, and the Fresnel lens 4 is located at the central portion. Since the optical image can be magnified with a small amount of distortion in various places around the peripheral portion, a clear hologram image corresponding to the large optical image can be obtained. Further, although the Fresnel lens 4 has a large aperture, the optical image can be sufficiently enlarged, and thus a sufficient depth of the hologram image can be obtained.

The light source 7, the liquid crystal shutter 8 and the Fresnel lens 4 are linearly arranged toward the hologram combiner 1, and the Fresnel lens 4 and the liquid crystal shutter 8 are arranged.
Since the distance between and can be made short, they can be arranged with a simple structure and in a small installation space.

In this case, a convex lens may be used in place of the Fresnel lens 4 in order to magnify the optical image in a linear arrangement and project it onto the hologram combiner 1 as in the present embodiment. However, if the aperture of the convex lens is increased in order to enlarge a relatively large optical image, the focal length is inevitably long. Therefore, the distance between the optical image generating means and the convex lens must be relatively large, and the space required for their arrangement becomes large. Further, in general, a convex lens is apt to cause image distortion in a portion near its peripheral edge, and therefore, even if the diameter of the convex lens is increased to enlarge a large optical image, it is difficult to obtain a clear hologram image. is there.

On the other hand, in the present embodiment, as described above, a relatively large light image can be satisfactorily enlarged to obtain a clear light image, and the light source 7, the liquid crystal shutter 8 and the Fresnel lens can be obtained. The arrangement space of 4 can be made small.

Further, in the apparatus of this embodiment, since the hologram combiner 1 is attached to the windshield 2, the windshield 2 can function as a lens to deepen the depth of the hologram image.

In this embodiment, the Fresnel lens 4 is moved up and down to adjust the depth of the hologram image. However, the liquid crystal shutter 8 is moved to adjust the depth of the hologram image. Of course, it is possible.

Further, although the solid Fresnel lens 4 is used in the present embodiment, a Fresnel lens type liquid crystal lens may be used. In this case, the focal point of the lens is electrically adjusted. It is also possible to adjust the depth of the hologram image.

[0031]

As is apparent from the above description, according to the present invention, the optical image generating means is arranged so that the optical path of the optical image from the optical image generating means to the hologram combiner is linear. And the optical image enlarging means is constituted by a Fresnel lens, and the Fresnel lens is arranged on the optical path of the optical image between the optical image generating means and the hologram combiner, so that it is small and simple. With this configuration, a good hologram image can be displayed, and with such a configuration, a relatively large optical image can be displayed well as a hologram image.

By providing the optical image generating means or the Fresnel lens movably in the optical path direction, the depth of the hologram image can be adjusted appropriately.

Furthermore, by attaching the hologram combiner to the windshield, the depth of the hologram image can be increased by giving the windshield a function as a lens.

[Brief description of drawings]

FIG. 1 is an explanatory side view showing the configuration of an example of a head-up display device of the present invention.

FIG. 2 is an explanatory side view showing the configuration of a conventional head-up display device.

[Explanation of symbols]

1 ... Hologram combiner, 2 ... Windshield, 3 ...
Optical image generating means, 4 ... Fresnel lens.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Katsuki Ichinose 1-4-1, Chuo, Wako-shi, Saitama Inside the Honda R & D Co., Ltd. (72) Inventor Tsuyoshi Hano 1-4-1, Chuo, Wako-shi, Saitama Honda R & D Co., Ltd.

Claims (3)

[Claims] 1. A hologram combiner provided in a visual field of a viewer, an optical image generating means for generating an optical image to be projected on the hologram combiner, and the light from the optical image generating means to the hologram combiner. A head-up display device, which is provided on an optical path of an image, and which includes an optical image enlarging means for enlarging and projecting an optical image generated by the optical image generating means onto the hologram combiner, from the optical image generating means. The optical image generating means is arranged to face the hologram combiner so that the optical path of the optical image to the hologram combiner is linear, and the optical image enlarging means is constituted by a Fresnel lens, and the Fresnel lens is used for the optical image. The head is characterized in that it is arranged on the optical path of the optical image between the generating means and the hologram combiner. Up display device. 2. The head-up display device according to claim 1, wherein the optical image generating means or the Fresnel lens is provided so as to be movable in the optical path direction. 3. The head-up display device according to claim 1, wherein the hologram combiner is attached to a windshield in front of a viewer.