JP2000233665A - Projection type holographic information display device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the dazzling to a vehicle in the use of an information display source having a high luminance by setting the direction of the light emitted from the information display source toward a light diffusive hologram screen as a reflecting member to between the just above direction of the vehicle and the backward oblique direction. SOLUTION: The information to be displayed on a projection type holographic information display device for vehicle can be properly selected according to display purpose such as speed of vehicle, engine speed, shift lever position, various alarms, navigation and the like. A light 4 containing information, which is emitted from an information display source 1 provided within the dashboard of a vehicle, is projected on a hologram screen 3 provided on the windshield glass 6 of the vehicle by an imaging optical system 2, and diffusively reflected, so that an observer 5 can visually confirm the information. Since the transmitted light 7 by the hologram screen 3 advances obliquely backward without reaching a forward vehicle 8, the dazzling to the driver of the forward vehicle 8 can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection holographic information display device for a vehicle, in which light emitted from an information display source does not affect other vehicles.

[0002]

2. Description of the Related Art In recent years, as a method of displaying information to a driver of a vehicle such as an automobile, a display device such as a head-up display (hereinafter, referred to as HUD) has been used. In this method, optical information projected from information projection means such as a liquid crystal display device is reflected on a combiner such as a half mirror or a hologram, which is a reflection member incorporated in a windshield of an automobile, and the information is displayed as a virtual image. is there.

[0003] By superimposing the display image on the foreground, there is an advantage that the driver can read information from the driving state with almost no movement of the viewpoint. Further, when a magnification is given to the combiner, the display image is displayed in an enlarged and distant view, so that there is also an effect of reducing the burden of the focus adjustment accompanying the driver's viewpoint movement. However, when a combiner having a magnification is used, a displayed image is distorted due to aberration. In particular, the dynamic distortion accompanying the movement of the viewpoint of the driver significantly deteriorates the visibility of the display. Further, in a combiner using a hologram, chromatic aberration occurs due to the spectral characteristics of the hologram, and there is a problem that a displayed image is blurred.

[0004] In order to solve these problems,
Japanese Patent No. 2694837 and Japanese Patent Application Laid-Open No. 9-179058 propose a projection type HUD in which a diffuse reflection type hologram in which a real image of a diffuser surface is recorded on a hologram surface is used as a reflection member and an information beam is formed on the hologram. I have.

[0005]

However, in the conventional HUD using the conventional diffuse reflection type hologram as a screen, light containing information is diffused in all directions, so that the light intensity perceived by an observer decreases. Therefore, in order to obtain sufficient display luminance, it is necessary to make the emission luminance of the information display source higher than that of the HUD of the combiner using the hologram, and the light emitted from the information display source passes through the hologram and travels to the vehicle ahead. There is a risk of arriving and dazzling the driver of the vehicle.

For example, FIG. 4 shows H of Japanese Patent No. 2694837.
It is a typical side view explaining UD and the problem. In these conventional HUDs, light 4 including information emitted from an information display source 1 is projected by an imaging optical system 2 onto a hologram screen 3 provided on a windshield of a vehicle, and diffused and reflected by the hologram screen 3 for observation. The person 5 visually recognizes the information.

In the projection type HUD, light 4 containing information is projected on the hologram screen 3 at an angle perpendicular or nearly perpendicular to the hologram screen 3 in order to prevent distortion and blurring of the projected image, as in the above-mentioned known example. Therefore, the direction of the light 4 including the information from the information display source 1 is the forward direction of the vehicle. Generally, a hologram has wavelength selectivity, so that only light in a specific wavelength range is observed by an observer 5.
, But light of other wavelengths is transmitted through the hologram and is emitted forward of the vehicle. Further, since the diffraction efficiency of the hologram is less than 100%, even the light in the specific wavelength region is partially transmitted.

[0008] The transmitted light 7 thus emitted to the front of the vehicle
Has a problem of reaching the vehicle 8 ahead and dazzling the driver of the vehicle 8 ahead. In particular, when the light source has a wide wavelength half-width such as incandescent lamps, most of the light is transmitted without being diffracted by the hologram as described above.

Also, since the hologram diffracts only light of a specific wavelength and has an angle dependence, the appearance of the hologram also has a problem that the color tone changes depending on the observation position and becomes stimulating. Further, light incident from the outside of the vehicle may become stray light due to reflection on the surface of the windshield and diffraction of the hologram, which may inconvenience an observer in the vehicle. It is an object of the present invention to provide a projection holographic information display device for a vehicle that solves the above-mentioned problems of the prior art.

[0010]

SUMMARY OF THE INVENTION The present invention provides a hologram reflecting member provided on a windshield of a vehicle, an information display source for generating information to be displayed as light, and connecting the light to the reflecting member. In a projection holographic information display device for a vehicle provided with an imaging optical system for forming an image, a light diffusing hologram screen is provided as the reflection member, and a direction of the light emitted from the information display source toward the hologram screen is changed. A projection holographic information display device for a vehicle, wherein the holographic information display device is located between a direction directly above the vehicle and an oblique direction behind the vehicle.

[0011] The present invention also provides the projection holographic information display device for a vehicle, wherein the hologram screen is provided on a sunshade portion of a windshield. Further, the light from the information display source is obliquely incident on the hologram screen, and the display surface of the information display source is inclined with respect to the optical axis so as to correct the blur of the projected image due to the oblique incidence. The present invention provides a projection holographic information display device for a vehicle. Further, the present invention provides the above-mentioned vehicle projection type holographic information display device in which the information input to the information display source is deformed in advance so as to correct the deformation of the projected image due to oblique incidence on the hologram screen.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings. FIG. 1 is a schematic side view of a projection holographic information display device for a vehicle according to the present invention. Light 4 including information emitted from an information display source 1 provided inside a dashboard or the like of a vehicle is projected by an imaging optical system 2 onto a hologram screen 3 provided on a windshield 6 of the vehicle. The light is diffusely reflected by 3 and the observer 5 visually recognizes the information. In the present invention, since the transmitted light 7 of the hologram screen 3 is configured not to reach the vehicle 8 located in front of the vehicle, it is possible to prevent the driver of the preceding vehicle from being dazzled, which has conventionally been a problem.

The configuration in which the transmitted light 7 does not reach the preceding vehicle 8 is such that the direction of the light 4 including the information emitted from the information display source 1 is between the direction directly above the vehicle and the oblique direction behind. I just need. Specifically, when the vehicle is placed horizontally,
In a substantially vertical plane including the front-rear direction of the vehicle, the light may start in a substantially vertical direction and extend backward to a direction of 65 ° (a direction of 35 ° from the horizontal direction). Here, it may be tilted forward by about 10 ° from the vertical direction. The light to the rear is blocked by the roof etc. and cannot be emitted outside the vehicle.
° or less.

In order to realize such an arrangement, it is preferable to dispose the hologram screen near the upper end of the windshield. When displaying an image in HUD, JIS R3
It is customary to avoid the test area A defined by 212, but this can be satisfied if a hologram screen is arranged near the upper end of the windshield. The positions of the information display source and the imaging optics with respect to the hologram screen are inside the dashboard, inside the meter hood, near the glove box,
The vicinity of the gear shift lever, the inside of the console box, and the like are preferable.

Further, it is preferable to dispose a hologram screen on the sunshade portion of the windshield, because the problem of the color tone of the appearance of the hologram described above is improved by the light absorption of the colored sunshade portion. Further, since the light incident from the outside is also reduced, the problem of the above-mentioned stray light is preferably improved. Since the sunshade is generally provided near the upper end of the windshield, the configuration in which the transmitted light 7 does not reach the preceding vehicle 8 can be satisfied at the same time.

FIG. 2 is an enlarged side view of a main part of the projection type holographic information display device for a vehicle according to the present invention. When placing the hologram screen on the windshield of the vehicle,
It is preferable that the hologram is sealed in the windshield in view of protection of the hologram. Generally, the windshield has a laminated glass structure, and the inside glass 61 and the outside glass 62 are joined by an intermediate film 63 made of polyvinyl butyral. When a sunshade is provided, the intermediate film near the upper end is partially colored to form a sunshade portion 64. If the hologram screen 3 is sealed between the vehicle interior glass 61 and the colored sunshade portion 64, the above configuration can be realized.

In the projection holographic information display device for a vehicle according to the present invention, light including information is often obliquely incident on the hologram screen. Therefore, the distance from the imaging optical system changes within the plane of the hologram screen.
For example, in the case of FIG. 2, the upper side of the hologram screen 3 is farther from the imaging optical system 2. As a result, the entire hologram screen becomes out of focus, or the image is enlarged as the distance from the imaging optical system increases, causing a phenomenon that the image is deformed into a trapezoidal shape or extends in one direction.

In order to improve image blur, it is preferable that the display surface of the information display source is inclined with respect to the optical axis so that the entire screen is focused. Further, in order to improve the image distortion, it is preferable that the information of the image input to the information display source is previously deformed so as to correct the distortion. For example, FIG. 2 shows an example in which an information display source including a backlight 11 and a transmission type liquid crystal display element 12 is used.
By tilting 2, the image blur can be improved. The light 4 containing the information diffracted by the hologram screen 3
The light that has been visually recognized and has not been diffracted is transmitted light 7.

Although the hologram screen is arranged near the upper end of the windshield in the above description, the information display source and the imaging optical system are arranged in the dashboard even when the hologram screen is arranged near the lower end of the windshield. By arranging the light so as to be emitted almost directly upward, the transmitted light can be prevented from reaching the vehicle ahead. However, in this configuration, since the distance between the imaging optical system and the hologram screen is short, an imaging optical system having a small aberration, a short focal length, and a large aperture is required to enlarge and form an image.

The windshield in the present invention is a safety laminated glass, and the type of glass is appropriately selected according to the application and design. The inside glass 61 is preferably a transparent glass to prevent light loss.
Can also use bronze or green colored glass. The material may be glass or resin glass such as polycarbonate and acrylic.

Further, in order to prevent light loss due to reflection on the glass surface, an antireflection coating may be applied to the inside surface of the vehicle. The type of hologram is preferably a volume phase hologram such as a Lippmann type having high diffraction efficiency and strong wavelength selectivity, but other holograms can also be used. As the hologram material, a photopolymer, a dichromated gelatin, a silver salt-based material, a photoresist or the like can be used. Photopolymers having high durability and excellent mass productivity are particularly preferred.

As an example of a method for manufacturing a light diffusing hologram screen, the method shown in FIG. 3 can be exemplified. The hologram photosensitive material 20 may be recorded by irradiating divergent light as reference light and scattered light as object light. The divergent light is laser light 23
Is diverged by the spatial filter 22. The diffused light is obtained by transmitting the laser light 24 through the diffuser 21. The distance R and the incident angle ψ of the reference light and the incident angle φ of the object light are appropriately determined according to the arrangement at the time of reproduction.
As another method, the image of the diffusion plate may be recorded on the hologram surface by a known two-stage exposure method.

The information display source according to the present invention has a function of emitting light for display. A display comprising a so-called light-receiving display element such as a liquid crystal display element is provided with a hot cathode tube, a cold cathode tube, a fluorescent display tube, and the like. Illumination with light emitted from a light source such as a halogen lamp, a metal halide lamp, a light emitting diode, and a semiconductor laser can be exemplified.

Separately, as the information display source, a light-emitting display element and a polarizer, which do not use a light-receiving display element but pattern and arrange the light source itself and generate specific information as light, are used. It may be a combination.
Self-luminous display elements include fluorescent display tubes, field emission displays, plasma displays, and organic E
Display blocking such as an L element can be exemplified, and an example in which light emitting elements such as a light emitting diode and a semiconductor laser are arranged can also be exemplified.

In the case where the light receiving type display element and the light source are used in combination, an appropriate light beam collimating member such as a lens system or a curved reflecting mirror, a light guiding member, a polarization controlling member, and the like are provided between the light receiving type display element and the light source. A viewing angle improving member or the like may be provided.

An imaging lens can be exemplified as an imaging optical system for projecting light from an information display source onto a hologram screen. An optical system in which aberration is corrected by an aspheric lens or a multi-component lens is preferable. Further, in order to increase the utilization rate of light from the information display source, a bright lens having a large aperture and a short focal length is preferable.

The information to be displayed on the projection holographic information display device for a vehicle according to the present invention is appropriately selected according to the display purpose. Examples include vehicle speed information, engine speed information, shift lever position information, information on various warnings, navigation information, and information on accessory devices such as air conditioners and audio devices. Also, information from outside the vehicle such as road information and parking lot availability information can be displayed.

In addition, an intelligent transportation system which has been recently developed, such as information on an inter-vehicle distance sensor with a preceding vehicle, an image of a blind spot taken by a CCD camera or the like, an image at the time of poor visibility such as at night, and a display of automatic toll collection, etc. Information corresponding to (ITS) can also be exemplified. Further, travel information and weather information obtained via an information network may be used. Further, information related to the operation business such as a delivery service of a courier service or dispatch information such as a taxi for business use can also be exemplified. The observer is mainly a driver of the vehicle, but may include a passenger seat and other passengers, and all of them. The passengers can also be provided with entertainment information such as television broadcasts and games.

Although the description has been given mainly of the projection holographic information display device for a vehicle provided with a hologram screen on a windshield, the projection holographic information display device for a vehicle having a hologram screen disposed on a rear glass or a side glass of a vehicle is also described. The present invention is applicable.

[0030]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a projection holographic information display device for a vehicle according to the present invention will be described below with reference to FIGS. Light 4 including information emitted from an information display source 1 provided inside a dashboard of a vehicle is projected by an imaging optical system 2 onto a hologram screen 3 provided on a windshield 6 of the vehicle, and the hologram screen 3 is provided. And the observer 5 visually recognizes the information. In the present embodiment, the transmitted light 7 of the hologram screen 3 travels obliquely rearward, so that it does not reach the vehicle 8 in front, and the dazzling to the driver of the vehicle 8 in front, which has conventionally been a problem, can be prevented.

The inclination angle of the windshield is about 27 °, and the distance from the imaging optical system 2 to the hologram screen 3 is 600 m.
m, and the incident angle of light was set to 79 ° with respect to a normal set on the hologram screen 3. The direction in which light is emitted is rearward, about 38 ° with respect to the horizontal direction, and the aforementioned condition (35)
°). The distance from the hologram screen 3 to the observer 5 is 450 mm, and the light diffraction angle is 50 with respect to the normal.
°.

The information display source comprises a backlight 11 comprising a hot cathode tube and a transmission type liquid crystal display element 12. Transmission type liquid crystal display element 1 for improving blur of projected image
2 was inclined by 50 ° with respect to the optical axis. In addition, the information of the input image is reduced to 1/3 in the vertical direction in advance in order to correct the deformation of the image extending in the vertical direction. The distance between the transmission type liquid crystal display element 12 and the imaging optical system 2 was 100 mm.

The hologram material used was an acrylic photopolymer manufactured by DuPont, and was exposed with the optical system shown in FIG. As the laser light, light having a wavelength of 647 nm of a Kr laser device was used. R = 600 mm, ψ = 36 °, φ = 19 °.
At the time of reproduction, it was 79 ° incident and the diffraction wavelength was 545 nm. Thus, a projection holographic information display device for a vehicle without dazzling the vehicle ahead was obtained.

[0034]

According to the present invention, it is possible to obtain a projection holographic information display device for a vehicle which does not disturb the vehicle ahead even when an information display source having a high luminance is used. In addition, it is possible to obtain a projection image with good visibility without blur or distortion in the display image. Further, the color tone and stray light of the appearance of the hologram can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic side view of a projection holographic information display device for a vehicle according to the present invention.

FIG. 2 is an enlarged side view of a main part of the projection holographic information display device for a vehicle according to the present invention.

FIG. 3 is a schematic plan view showing an example of a method for manufacturing a hologram screen.

FIG. 4 is a schematic side view showing an example of a conventional HUD.

[Explanation of symbols]

 1: information display source 2: imaging optical system 3: hologram screen 4: information-containing light 5: observer 6: windshield 7: transmitted light 8: vehicle ahead 11: backlight 12: transmission display device 20: Hologram photosensitive material 21: Diffusion plate 61: Interior glass 62: Exterior glass 63: Intermediate film 64: Sunshade

Claims (4)

[Claims] 1. A hologram reflecting member provided on a windshield of a vehicle, an information display source for generating information to be displayed as light, and an image forming optical system for forming the light on the reflecting member. In the vehicle projection holographic information display device provided, a light-diffusing hologram screen is provided as the reflection member, and the direction of the light emitted from the information display source toward the hologram screen is directly above and behind the vehicle. A projection-type holographic information display device for a vehicle, wherein the holographic information display device is disposed between the vehicle and the oblique direction. 2. The projection holographic information display device for a vehicle according to claim 1, wherein said hologram screen is provided on a sunshade portion of a windshield. 3. The light from the information display source is obliquely incident on the hologram screen, and the display surface of the information display source is inclined with respect to the optical axis so as to correct the blur of the projected image due to the oblique incidence. 3. The projection holographic information display device for a vehicle according to claim 1, wherein 4. The projection holographic information for a vehicle according to claim 3, wherein the information input to the information display source is deformed in advance so as to correct the deformation of the projected image due to oblique incidence on the hologram screen. Display device.