JPH1067257A - Head up display - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible for observers in respective predetermined directions per a plurality of regions to confirm an image of a pattern shape visually by diffracting light from a light source toward a hologram for combiner by a hologram for light source and irradiating light in a whole region of the hologram for combiner. SOLUTION: Light emitted from a light source for display 13 is reflected and diffracted by a hologram for light source 14 and is irradiated toward a combiner 12 provided with a hologram for combiner. The hologram combiner 12 is installed at an end on the opposite side to observers 15, 16 of a case body 11 and obliquely in opposition to the display light source 13. Light irradiated in the hologram for light source 14 is reflected and diffracted in predetermined directions per each region so that the observers 15, 16 in the directions can confirm an image having the same pattern shape visually. Information light which is reflected and diffracted by the combiner 12 is irradiated toward the directions of observation 15, 16 of a plurality of observers so that the plurality of observers can observe it at respective observation positions.

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 (HUD) for a vehicle.

[0002]

2. Description of the Related Art HUD has recently been used as a method of displaying information to a driver inside a car or the like.
This is to project the optical information projected from the information projection means such as a liquid crystal display device on a combiner composed of a hologram or a half mirror incorporated in a windshield or the like of an automobile,
The information can be read by the driver from the driving state with almost no movement of the viewpoint.

In particular, a hologram using a combiner has a function of diffracting optical information toward a driver and a lens function, so that the optical information can be diffracted in the direction of the driver's field of view. Alternatively, it is possible to form an image at an arbitrary position without using an optical system such as a lens, and a feature that a high luminance display image can be obtained without deteriorating the foreground luminance. , HUD are effective as combiners.

FIG. 6 is a conceptual diagram showing an example of a conventional HUD. A light ray 74 including information to be displayed, which is emitted from a light source 71 and passes through a transmission type liquid crystal display element 73 through a lens system 72, is reflected by a reflection element 75, and a windshield 76 of the vehicle body.
The display image 79 is visually recognized at the observation position 78 by the driver.

[0005] The lens system 72 has a function as a collimator.
7, so that the display images of the speed display and the warning display can be formed far away.

Further, since the hologram 77 has a wavelength selecting function, an image of a desired color can be displayed. Usually, the color is single, but multi-color display by multiple exposure is also possible, and the amount and quality of display information can be improved. For example,
By making the speed display green and the warning display red,
Information can be more accurately transmitted to the driver.

As such a hologram combiner, a reflection type hologram is usually used. In the production of a reflection type hologram, reference light is irradiated from one surface of a hologram photosensitive material and object light is irradiated from the other surface. Then, a diffraction grating is formed in the photosensitive material.

In the hologram photosensitive material, these two
The two laser beams interfere with each other to produce light-dark interference fringes, which are recorded as a diffraction grating based on the difference in physical properties such as the refractive index or density of the photosensitive material. In this type of reflection hologram, when the incident angle of light and the reflection diffraction angle are different, the diffraction grating surface is inclined with respect to the hologram surface and is not parallel to the surface.

This is because the combiner was manufactured such that the incident angle of the display light from the display light source containing the information and the angle of diffraction of the information light from the combiner visually recognized by the driver were different.
Since the angle of incidence and the angle of diffraction can be different, the degree of freedom in designing the HUD increases. In such an HUD, the diffraction direction of the display light emitted from the display light source is only one direction.

JP-A-5-278498 and JP-A-5-278498
JP-A-101267 discloses a HUD in which a diffraction direction of display light emitted from a display light source is diffracted in a plurality of directions of a driver and a passenger such as a passenger seat. Here, so that the display light is diffracted in a plurality of directions, one reference light and a plurality of object lights are used, or one reference light and one object light are used to perform the exposure multiple times to manufacture. .

[0011]

Such hologram combiners usually use volume holograms to increase wavelength selectivity. Volume-type holograms have excellent wavelength selectivity, which can reduce chromatic aberrations and suppress blurring of the displayed image, but they also have excellent angle selectivity, so this angle selectivity is used instead. The viewing range due to image diffraction is narrowed.

That is, in a hologram HUD that can be viewed only by a normal driver, if the driver in the direction in which the hologram combiner diffracts the displayed image moves up and down the viewpoint slightly, the displayed image becomes difficult to recognize. The situation is the same in a hologram HUD that can be visually recognized from a plurality of directions. When observing from a viewpoint in a plurality of specific directions that diffract a display image, the display image can be recognized. When moving to, there is a problem that recognition of the display image becomes difficult.

An object of the present invention is to solve the above-mentioned drawbacks of the prior art, and to provide an HUD which has not been known before.
Is to provide a new.

[0014]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and comprises a display light source and a hologram that diffracts light emitted from the display light source toward an observer. In a head-up display having at least a combiner provided with the combiner, the combiner hologram has a plurality of regions in a horizontal direction, and an image of the same predetermined pattern shape is recorded in each of the plurality of regions, and a predetermined image is formed for each of the plurality of regions. The display light source is provided with a light source and a band-shaped light source hologram, and the light emitted from the light source is combined by the light source hologram. The hologram is diffracted toward the hologram for illumination and irradiates the entire area of the hologram for combiner, and the pattern shape is given to an observer in a predetermined direction for each of a plurality of areas. It is to provide a head-up display, characterized in that to visually recognize the image.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in more detail with reference to the drawings. FIG. 1 is a conceptual diagram showing an example of the HUD of the present invention. The light emitted from the display light source 13 is reflected and diffracted by the light source hologram 14, and is emitted toward the combiner 12 provided with the combiner hologram. The information light reflected and diffracted by the combiner 12 is irradiated toward observation directions 15 and 16 of a plurality of observers, and is observed by a plurality of observers at respective observation positions. In this example, the optical system including the display light source 13 is installed in one housing 11.

The hologram combiner 12 is installed diagonally opposite the display light source 13 at the opposite end of the casing 11 to the observers 15 and 16. The hologram used here has a plurality of regions in the horizontal direction, and an image of the same predetermined pattern shape is recorded in each of the plurality of regions. The light applied to the light source hologram 14 is reflected and diffracted in a predetermined direction for each region so that an image in the same pattern shape is visually recognized by an observer in that direction.

The light source 13 used here is a liquid crystal display with a backlight and displays the vehicle speed, but the light source may be a CRT, EL, VFD or the like, and the display content may be a warning pattern or a direction indication. .

The reflection type combiner has a mark for prompting refueling, a mark for indicating overheating of the engine, and the like.
A three-dimensional image such as is often performed with an image hologram may be recorded.

The position of the display light source 13 is not limited to the illustrated example, but may be installed below the combiner 12. In this case, a reflection member (not shown) that reflects display light from the display light source toward the combiner 12 is installed at a position where the illustrated display light source is installed. This reflecting member
Plane mirrors, concave mirrors, and holograms having specific wavelength selectivity may be used.

In this example, the observers 15 and 16 are assumed to be a driver and a passenger in the passenger seat. The combiner according to the present invention is manufactured such that the display image is diffracted in the direction of the observer even if the driver and the passenger in the passenger seat slightly lose their postures, that is, even if the line of sight is shifted in the left and right direction, and furthermore, the position is shifted in the vertical direction. Have been. In particular, the degree of freedom in the vertical direction is large, and the displayed image can be observed regardless of the height of the observer.

A combiner having such a function is a hologram combiner using a hologram manufactured as follows. FIG. 2 is a conceptual diagram illustrating a method for producing a combiner hologram. Laser light (wavelength 514.5 nm in this example) emitted from the laser device is split into two light beams by a beam splitter, and one (201) is irradiated toward the objective lens 21. The other (202)
Is transmitted through the cylindrical lens 26 and diffused
Is applied to the hologram photosensitive material 24 through the. The beam 201 directed to the objective lens 21 is transmitted through the objective lens, and then the mask 2 having a predetermined pattern is cut out.
2, the hologram photosensitive material 24 is irradiated as object light (23) having a predetermined pattern.

The hologram photosensitive material 24 is light-shielded by a light-shielding mask 25 so as to be divided into predetermined regions, except for specific portions. Each time the exposure of the specific portion is completed, the light-shielded area is changed so that the next area is exposed. The hologram thus produced is a multiplex hologram divided into a plurality of regions.

When changing the light-shielded area, the position of the diffusion lens 27 (the incident direction of the beam 202) is changed.
Is changed as shown in FIG. 3, the display image can be diffracted in a predetermined direction for each of the divided predetermined regions shown in FIG. 3 (341, 342, 343). As shown in the drawing, even if the pattern has the same shape for each region, a slight distortion of the shape is provided, so that the display image actually observed by the observer can be prevented from being distorted.

The hologram for a combiner used in this example had a cylindrical shape with a radius of curvature of 6 cm, and had an arc length of 10 cm and a height of 10 cm. The entire hologram area is divided into 20 areas, each having a width of 5 m.
m, the above-mentioned predetermined pattern was recorded in each area.

FIG. 4 shows a method of manufacturing a light source hologram. The light source hologram diffracts the light emitted from the light source 13 toward the combiner 12 as described above, and has a band shape. Laser light (wavelength 514.5 nm in this example) oscillated from the laser device is split into two light beams by a beam splitter, and one light beam (50
1) is irradiated toward the hologram photosensitive material 55 through the objective lens 51, the cylindrical lens 52, and the convex lens 53. At this time, a light shielding mask 54 is interposed between the hologram photosensitive material 55 and the convex lens 53 in order to eliminate unnecessary scattered light.

The other (502) transmits through the objective lens 56, and after being diffused, irradiates the hologram photosensitive material 55 through the mask 57. Thus, a hologram for a light source is manufactured. In this example, the strip-shaped light source hologram had a width of 18 cm and a height of 5 cm.

Although the above-described method is related to a combiner for a single color, the hologram photosensitive material for a combiner and the hologram photosensitive material for a light source are processed by a similar process to light of a plurality of wavelengths (for example, a wavelength of 674 nm or 633).
If the same exposure is performed using red (nm) and blue (wavelength 488 nm), color display is possible. In addition to these wavelengths, other red, green,
It is also possible to select light of a wavelength of blue color, and it is also possible to perform color exposure by exposing the preliminary hologram at the same wavelength by appropriately changing the opening angle of the hologram.

The hologram photosensitive material of the present invention includes:
Photopolymer, dichromated gelatin sensitized with methylene blue or the like, polyvinyl carbazole, silver salt-based materials, and the like can be used. In addition, the hologram in the present invention can use not only a volume hologram but also a two-dimensional relief hologram.

Although the method of manufacturing the combiner for displaying the variable information has been described above, a specific still three-dimensional image, that is, a warning display indicating that the seat belt is fastened or the remaining fuel amount is small can also be recorded on the combiner hologram. In this case, the light-scattering object having the warning display mark shape may be provided in the preliminary first exposure stage, that is, in place of the diffusion plate 21 in FIG. 2, and the exposure may be performed as described above. At this time, the above-mentioned warning display mark may be exposed so that red or the like is reproduced. Further, the mark indicating that the headlight is facing upward may be exposed so as to be reproduced in blue or the like. With such exposure, an image can be displayed in a desired color even when white light is used as irradiation light.

In the above example, a halogen lamp was used as the light source 13. In addition, a laser diode (LD) can be used as shown in FIG. In this example, a red LD and a green LD are used. The laser beams emitted from the red LD 61 and the green LD 62 are combined by the half mirror 63 and enter the polygon mirror 65 via the convex lens 64. The above two types of laser light are enlarged and scanned by a polygon mirror 65 and are irradiated toward a belt-like light source hologram via an f-θ lens 66. By using such a light source, a display image that is more vivid than a white light source can be obtained.

As another installation example of the combiner, the structure is not limited to the structure shown in FIG. 1, but may be a structure in which the combiner is mounted on the windshield as shown in FIG.

[0032]

According to the present invention, a hologram for a combiner is divided into a plurality of regions, and a display image is diffracted in a direction corresponding to each region, so that the region where the display image can be observed can be enlarged. .

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing an example of a HUD of the present invention.

FIG. 2 is a conceptual diagram showing an example of a method for producing a combiner hologram according to the present invention.

FIG. 3 is a conceptual diagram showing an example of a part of a method for producing a combiner hologram in the present invention.

FIG. 4 is a conceptual diagram showing an example of a method for producing a hologram for a light source according to the present invention.

FIG. 5 is a conceptual diagram showing an example of a light source according to the present invention.

FIG. 6 is a conceptual diagram showing a conventional HUD.

[Explanation of symbols]

 11: Casing 12: Hologram combiner 13: Light source 14: Hologram for light source 15: Driver's seat observer 16: Passenger's seat observer

Claims (1)

[Claims] 1. A head-up display comprising at least a display light source and a combiner having a hologram for diffracting light emitted from the display light source toward an observer, wherein the combiner hologram is provided in a plurality in a horizontal direction. Having an area, an image of the same predetermined pattern shape is recorded in each of the plurality of areas, and diffracts light of the image of the pattern shape in a predetermined direction for each of a plurality of areas,
The display light source is provided with a light source and a band-like light source hologram, and the light emitted from the light source is diffracted toward the combiner hologram by the light source hologram and is applied to the entire area of the combiner hologram. A head-up display characterized by allowing an observer in a predetermined direction to visually recognize an image of the pattern shape for each region.