JPH04356235A - Head-up display device - Google Patents

Abstract

PURPOSE:To provide a compact light head-up display device capable of imaging display information in a remote place with a simple construction. CONSTITUTION:In a head-up display device for laying display information for a display element 12 and other visual information overlapping each other spatially through a transparent light flux combining element like a windshield 15 to be observed in the same field of view, an optical system before the display information is projected on the light flux combining element 15 is provided with a diffraction optical element 13 having a remote imaging action.

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 (hereinafter referred to as HUD) that allows display information from a display element and other visibility information to be observed within the same field of view.

0002

[Prior Art] A HUD projects and displays necessary composite information on a beam combining element (hereinafter referred to as a combiner) such as a multilayer film reflector or a hologram diffraction grating, and transmits visibility information from the outside world through the combiner. This allows both pieces of information to be observed together within the field of view. That is, since two types of information can be observed without moving the line of sight, they are installed in, for example, the cockpit of an airplane or the driver's seat of various vehicles.

FIGS. 6 to 8 show the configuration of an example of a conventional HUD. The HUD shown in FIG. 6 is installed in the driver's seat of an automobile, and displays images such as speed displayed on a display 1 by a reflecting mirror 2 onto a front window 3 as a combiner. Further, the HUD shown in FIG. 7 is provided with a collimating lens 4 on the optical path connecting the reflecting mirror 2 shown in FIG. 6 and the front window 3 to make the light incident on the front window 3 nearly parallel light.

Furthermore, in the device shown in FIG. 8, a display 1 and a reflecting mirror 2 are housed in a projector 5, a protective glass 6 is provided at the exit of the light reflected by the reflecting mirror 2, and a protective glass 6 is provided opposite to the protective glass 6. A combiner 7 using a hologram element is attached.

[0005]

[Problems to be Solved by the Invention] According to the HUD shown in FIG. 6, since the imaging position of the display image projected on the front window 3 is closer to the driver's eyes 8 than the external background, the focal point of the eyes 8 is There was a problem in that it was a burden to move.

In addition, in the HUD shown in FIG. 7, the collimating lens 4 makes the light incident on the front window 3 nearly parallel, so the image formation position of the displayed image becomes distant from the eye 8, which reduces the burden of focal shift on the eye 8. is reduced. However, this configuration requires a lens with a large diameter, resulting in problems such as an increase in the size of the device, an increase in overlap, and an increase in cost. Note that a half mirror may be provided in the front window 3 shown in FIGS. 6 and 7 in some cases.

Furthermore, in the HUD shown in FIG. 8, the hologram combiner 7 has the effect of diffracting the reflected light into nearly parallel light, so that the image formation position of the displayed image is far away from the eye 8, as in the case shown in FIG. However, it is possible to reduce the size and weight of the device. However, since the hologram combiner 7 has poor environmental resistance such as temperature, it cannot be installed in the front window 3 which is exposed to sunlight and undergoes large temperature changes. Furthermore, even if it is attempted to install the combiner 7 away from the front window 3, there is not enough space on the instrument panel, and installing it in front of the driver poses a problem in terms of driving safety.

The present invention has been made in view of the above points, and it is an object of the present invention to provide a small and lightweight HUD that has a simple structure and can image display information at a distance.

[0009]

[Means for Solving the Problems] The HUD of the present invention spatially superimposes display information from a display element and other visibility information via a light-transmissive beam coupling element, so that the display information is displayed within the same field of view. The head-up display device is characterized in that a diffractive optical element having a long-distance imaging function is provided in the optical system before projecting display information onto the light beam coupling element.

0010

[Operation] In the HUD having the above configuration, the display information emitted from the display element is diffracted into nearly parallel light by the diffraction optical element before being projected onto the beam coupling element, so the display information is imaged at a distance. Ru. As a result, display information and other visibility information can be observed in a superimposed manner within the same visual field while reducing the burden of shifting the focal point on the eye. Moreover, since the diffractive optical element is plate-shaped and can be separated from the optical coupling element and placed at any position on the optical path, the HUD can be made smaller and lower in cost.

[0011]

Embodiments Hereinafter, embodiments of a HUD according to the present invention will be described with reference to the drawings.

FIG. 1 shows the configuration of a first embodiment of the present invention. On one side of the projector 11 is a high-intensity VF as a display element.
A plate-shaped hologram diffraction element 13, which is a diffraction optical element having a far-field imaging function, is provided on the other side at an angle of 45 degrees with respect to the optical axis of the VFD 12. Further, the wall surface of the projector 11 through which the light diffracted and reflected by the hologram diffraction element 13 is emitted is open, and this opening is sealed with a transparent protective glass 14. Furthermore, the projector 11 is filled with an inert gas such as N2 or Ar to prevent the hologram diffraction element 13 from deteriorating. Further, the projector 11 is attached to the lower part of the front window 15 so that the emitted light enters the front window 15 as a combiner at an angle of approximately 45 degrees.

Next, the operation of this embodiment will be explained. VFD1
The light emitted from the point light source 16 of hologram diffraction element 1
The light beam is diffracted by the light beam 3, becomes almost parallel light, and is projected onto the front window 15 through the protective glass 14. FIG. 2 shows the state of the light diffracted and reflected by the hologram diffraction element 13 at this time. In FIG. 2, solid lines indicate light rays according to this embodiment, and dashed lines indicate light rays reflected by a conventional reflector. As a result, display information such as a speed display emitted from the VFD 12 appears to be displayed several meters in front of the eye 17. At the same time, external light, which is other visibility information,
It can be seen through the front window 15.

According to this embodiment, the hologram diffraction element 1
3, the light from the VFD 12 can be diffracted into almost parallel light, so when it is projected onto the front window 15, it is imaged in the distance, and it can be easily overlapped with external light without putting a burden on the focus of the eye 17. You can see it. Moreover, since the hologram diffraction grating 13 is smaller and lighter than a lens or the like, the HUD can be made smaller and lighter. Furthermore, since the front window 15 can be used as a combiner, there is no need to prepare a separate combiner, and cost reduction is also achieved.

FIGS. 3 and 4 show the configurations of second and third embodiments of the present invention, respectively. In these figures, Figure 1
The same reference numerals are given to the parts corresponding to the parts of the first embodiment shown in FIG.

In the second embodiment shown in FIG. 3, a reflecting mirror 21 is provided at the position of the hologram diffraction element 13 shown in the first embodiment, and a transmission type hologram diffraction element 22 is bonded to the inner surface of the transparent protective glass 14. It is something.

According to this embodiment, the light emitted from the VFD 12 is reflected by the reflecting mirror 21 and diffracted by the transmission type hologram diffraction element 22 bonded to the inner surface of the transparent protective glass 14 to become almost parallel light, which is reflected by the front window. 15. Therefore, the same effects as in the first embodiment can be obtained.

In the third embodiment shown in FIG. 4, a transmission type hologram diffraction element 22 is bonded to the inner surface of the transparent protective glass 14 shown in the first embodiment. The diffraction element 22 and the diffraction element 13 are designed so that the directions in which chromatic aberration occurs are opposite to each other.

According to this embodiment, the light emitted from the VFD 12 is diffracted into nearly parallel light by the hologram diffraction element 13 or 22 and projected onto the front window 15, thereby obtaining the same effect as in the first embodiment. be able to. Moreover, chromatic aberration can be improved.

In each of the above embodiments, VF is used as a display element.
Although the case where D12 is used has been described, a liquid crystal display, CRT, LED display, plasma display, etc. may be used as the display element.

FIG. 5 shows a method of manufacturing the hologram diffraction elements 13 and 22 used in each of the above embodiments. First, dichromate gelatin is coated onto a polyethylene terephthalate (PET) film fixed on a glass substrate to a thickness of 10 μm, and this is used as a hologram sensitive material. This hologram sensitive material 31 is placed in an exposure optical system as shown in FIG. An optical switch 33 is provided at the laser beam exit of the laser 32 which is a light source, and when the optical switch 33 is opened, the laser beam emitted from the laser 32 is diffused by a lens 34 . The laser light diffused by the lens 34 passes through the pinhole 35 and becomes parallel light by the collimating lens 36. This parallel light is projected onto the half mirror 37, part of which is reflected in a right angle direction, and the other part of which travels straight.

The laser beam reflected in the right angle direction is reflected by the total reflection mirror 38, diffused by the lens 39, and enters the spherical wave lens 40. The laser beam, which is turned into a spherical wave beam 41 by the spherical wave lens 40, enters the hologram sensitive material 31 and exposes the volume phase hologram diffraction grating.

On the other hand, the laser beam that has passed straight through the half mirror 37 is diffused by the lens 42, and further converted into parallel light by the collimating lens 43 and then reflected by the total reflection mirror 4.
4. The laser beam reflected by the total reflection mirror 44 is diffused by the lens 45 and becomes a parallel beam 47 by the collimating lens 46, which is applied to the hologram sensitive material 3.
1. In this way, the volume phase hologram diffraction grating is exposed on the hologram sensitive material 31 by the two-beam method. This diffraction grating, together with the PET film, is peeled off from the glass substrate and adhered to the inner surface of the projector 11 or the inner surface of the transparent protective glass 14, as shown in FIGS. 1 to 4.

[0024]

[Effects of the Invention] As explained above, according to the HUD of the present invention, a diffraction optical element having a long-distance imaging function is provided in the optical system before projecting display information onto the beam coupling element, so that simple operation can be achieved. Using a small and lightweight HUD structure, display information can be imaged at a distance, and other visibility information can be observed in the same field of view without putting a strain on the eye's focus. can.

[Brief explanation of the drawing]

FIG. 1: First head-up display device of the present invention.
An explanatory diagram showing the configuration of an embodiment of

[Fig. 2] An explanatory diagram showing the optical path of diffracted light by the hologram diffraction element shown in Fig. 1.

FIG. 3 is an explanatory diagram showing the configuration of a second embodiment of the present invention.

FIG. 4 is an explanatory diagram showing the configuration of a third embodiment of the present invention.

[Figure 5]
Explanatory diagram showing the method for manufacturing a hologram diffraction element

FIG. 6 is an explanatory diagram showing the configuration of a first example of a conventional head-up display device.

FIG. 7 is an explanatory diagram showing the configuration of a second example of a conventional head-up display device.

FIG. 8 is an explanatory diagram showing the configuration of a third example of a conventional head-up display device.

[Explanation of symbols]

12 VFD (display element)

Claims (1)

[Claims] 1. A head-up display device in which display information from a display element and other visibility information are spatially superimposed via a light-transmissive beam coupling element so that they can be observed within the same field of view. A head-up display device, characterized in that a diffractive optical element having a long-distance imaging function is provided in an optical system before projecting the display information onto the light beam coupling element.