JP2000280786A - Vehicular projection type holographic information display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable an observer of a rear seat to visually confirm information by generating the information to be displayed as the light from an information display source, and forming an image by a coupling optical system on a light diffusive vehicular projection type hologram screen for arranging the light between a car inside front seat and the rear seat. SOLUTION: The light 4 including information is projected from a projector 3 provided in the vicinity of a center panel of a vehicle to form an image on a hologram screen 1 arranged between a front seat and a rear seat. That is, the light 4 including information issued from a transmission type liquid crystal display element 32 is extensively projected on the hologram screen 1 by an image forming optical system 33 to be diffusively diffracted on the hologram screen 1 to be visually confirmed by an observer 2 as the image-like duffisive light 6. A large display can be obtained even if the transmission type liquid crystal display element 32 is small, and since the hologram screen 1 can also be constituted by sticking a hologram 10 to a transparent base board 11, weight can be reduced even in a large type.

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, and more particularly to a projection holographic information display device for a vehicle that allows an observer in a rear seat of a vehicle to visually recognize information.

[0002]

2. Description of the Related Art In recent years, an information display device such as a head-up display has been used as a method for displaying information to an observer of a vehicle such as an automobile. This is a combiner (display unit) that projects optical information from an information projection unit such as a liquid crystal display device, and is composed of a half mirror, hologram, etc. incorporated in a windshield or the like of an automobile.
And the information is displayed as a virtual image. Then, by superimposing the display image on the foreground through the windshield, the driver can read information from the driving state with almost no movement of the viewpoint. In addition, the liquid crystal display element itself is spreading as a monitor of a car navigation system, and is used by being attached to a dashboard or the like.

FIG. 6 is a schematic perspective view showing a conventional information display device for a rear seat observer. Here, there are not many types of devices for displaying information to a rear-seat observer, but as shown in FIG. 6, a liquid crystal display element 78 is embedded in the back of a driver's seat or a passenger's seat 79 to provide a liquid crystal display. It is known that the rear seat observer 2 observes the light 74 including the information emitted from the element 78. Further, only a configuration in which a support member is separately provided and the information display element is fixed is known.

As a purpose of using the information display device of the rear-seat observer, a functioning as an office is required for a moving vehicle against the background of intensified competition and rapid change in a business environment in recent years. I have. For example, corporate VIP
In some cases, business information is examined and decisions are made using information communication and computer networks. Also, in general households, a large number of observers in the rear seats demand information display for recreational purposes such as television and games due to the spread of RV vehicles.

[0005]

By the way, in any application, a large-sized display is required from the viewpoint of visibility and simultaneous multi-person appreciation. However, conventionally, since the seat of the vehicle has only a limited size, there is a limit in the size of the information display element to be embedded, and there is a problem that a display of a sufficient size cannot be obtained.

In order to embed an information display element in a seat, the information display element needs to be thin and lightweight. In addition to the liquid crystal display element, a plasma display, an organic EL display, etc. can be used, but the large ones are very heavy, technically difficult to commercialize, and extremely expensive. There was a point, and it was difficult to increase the size. Further, when these displays are fixed by the support member, there is a problem that the display may move with a heavy display device due to the vibration of the vehicle, and the visibility is not good. In addition, there is also a problem that the weight increases and the load on the support member increases as the size increases. Furthermore, there is a danger of contact with passengers in the event of an accident.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, and to provide a large-area displayable, lightweight, projection holographic information display device for a vehicle, which allows an observer in a rear seat of the vehicle to visually recognize information. Is to do.

[0008]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and at least includes a light diffusion type hologram screen, an information display source for generating information to be displayed as light, and In a projection holographic information display device for a vehicle, comprising an imaging optical system that forms light on a hologram screen, the hologram screen is disposed between a front seat and a rear seat in the vehicle, and a rear seat observer is provided. A projection holographic information display device for a vehicle, characterized in that information is visually recognized.

Further, the information display source is arranged on a front seat side in the vehicle, and the hologram screen transmits and diffracts light containing information in a diffusive manner so that the information can be visually recognized by an observer in a rear seat. Provided is a projection holographic information display device. Further, the present invention provides the above-mentioned projection holographic information display device for a vehicle, wherein the hologram screen is attached to a transparent substrate. Further, the present invention provides the above-mentioned projection holographic information display device for a vehicle, wherein the hologram screen can be wound up and stored in a roll shape and can be pulled out and used as needed.

[0010]

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 view of a projection holographic information display device for a vehicle according to an embodiment of the present invention.
Light 4 including information is projected from a projector 3 provided near a center panel of the vehicle, and forms an image on a hologram screen 1 arranged between a front seat and a rear seat. The light 4 containing information is diffusely transmitted and diffracted by the hologram screen 1 and is visually recognized as information by the observer 2 in the rear seat. Also, 6
Is an image-like diffused light, and 9 is a front seat.

FIG. 2 is an enlarged view of a main part of the projection holographic information display device for a vehicle shown in FIG. Projector 3
Is composed of a backlight 31, a transmissive liquid crystal display element 32, and an imaging optical system 33. In the present invention, a device that generates information as light is referred to as an information display source. In this embodiment, a combination of a backlight 31 and a transmission type liquid crystal display element 32 is an information display source.

The light 4 containing information emitted from the transmissive liquid crystal display element 32 is enlarged and projected on the hologram screen 1 by the imaging optical system 33, diffracted diffusively on the hologram screen 1, and the image-like diffused light 6 And is visually recognized by the observer 2. As described above, since the light 4 containing information is enlarged and projected on the hologram screen 1, even if the original transmission type liquid crystal display element 32 is small, a large display can be obtained by such a projection form. . That is, unlike the related art, a large-area display can be obtained using a small and inexpensive display element. In addition, the hologram screen 1 can have a configuration in which the hologram 10 is attached to the transparent substrate 11, and has a simple configuration, so that even if it is large, it can be reduced in weight.

Further, in the projection holographic information display device for a vehicle according to the present invention, of the light from the information display source, the light transmitted through the hologram screen is blocked by the opaque portion of the vehicle and cannot be emitted to the outside. There is no danger of dazzling the driver of the vehicle. First, holograms generally have wavelength selectivity and diffract only light in a specific wavelength range.
Light of other wavelengths is transmitted through the hologram. Therefore, since the incident direction and the diffracted light direction of the light in the specific wavelength range can be arbitrarily set when creating the hologram, the incident direction of the light in the specific wavelength range can be set in a direction in which the transmitted light is blocked by the opaque portion of the vehicle. That's what it means.

Further, since the hologram has a diffraction efficiency of less than 100%, even light in a specific wavelength range is partially transmitted, and if this transmitted light is emitted outside the vehicle, the driver of another vehicle is dazzled. However, in the present invention, there is no such problem because transmitted light is not emitted to the outside as described above.

As the configuration of the projection holographic information display device for a vehicle according to the present invention, two configurations of a transmission type and a reflection type are possible. As shown in FIGS. 1 and 2, the transmission type includes an information display source on the front seat side of the vehicle, and the hologram screen 1 diffracts light 4 including information in a transmission-diffusive manner.
This allows the observer 2 in the rear seat to visually recognize image-like information.

FIG. 3 is a schematic view of a transmissive projection holographic information display device for a vehicle according to another embodiment of the present invention. In this figure, a projector 53 comprising an information display source and an imaging optical system is arranged on a ceiling on the front seat 59 side, and light 54 including information is projected on a hologram screen 51 arranged between the front seat 59 and the rear seat 57. Image. The light 54 including the information is transmitted and diffracted by the hologram screen 51 in a diffusive manner, and the diffused light 5 is transmitted to the observer 2 sitting on the rear seat 57.
6 is visually recognized as image-like information.

On the other hand, FIG. 4 is a schematic view of a reflection type projection holographic information display device for a vehicle in still another embodiment according to the present invention. In this reflection type, a projector 63 including an information display source and an imaging optical system is connected to a rear seat 67.
And the light 64 including the information is imaged on the hologram screen 61 disposed between the front seat 69 and the rear seat 67. The hologram screen 61 diffracts the light 64 containing the information in a reflective and diffusive manner, and makes the information visible to the observer 2 in the rear seat 67. The light 64 containing information is reflected and diffused by the hologram screen 61 and diffracted, and is visually recognized as image-like information by the observer 2 in the rear seat 67. The hologram screen 61 is housed in the form of a roll 12 as described later.

In each of the above embodiments, the position of the projector including the information display source and the imaging optical system is as follows: near the center panel, inside the dashboard, inside the meter hood, near the glove box or near the gear shift lever, inside the console box, It can be placed near the ceiling, near the back seat, and the like. And
As described above, for example, in the embodiment of FIG. 3, by determining the position of the projector 53 so that the transmitted light 55 is emitted to the rear seat 57, the transmitted light 55 can be prevented from being emitted outside the vehicle. In addition, in FIG. 4, by determining the position of the projector 63 so that the transmitted light 65 is irradiated on the ceiling, the transmitted light 65 can be blocked and not emitted to the outside of the vehicle.

Here, with respect to the transmitted light, dazzling to the driver of the vehicle due to reflection from the rearview mirror or the like must be prevented. Regarding the reflection of the transmitted light in the room mirror, since the room mirror is near the windshield, which is a transparent portion, for example, in the present invention, the transmitted light is directed to the ceiling as shown in FIG. Direct reflection is suppressed. In addition, regarding the dazzling to the rear seat observer due to the transmitted light and the surface reflected light of the hologram screen,
Light can be incident obliquely, and it is easy to take measures by changing the incident angle and the diffraction angle as described above.

The structure of the hologram screen used in the projection holographic information display device for a vehicle according to the present invention is preferably a structure in which a hologram is adhered to a transparent substrate. By using such a transparent substrate, when the driver looks backward through the hologram screen, safety can be easily confirmed. Since the hologram diffracts only light of a specific wavelength and transmits light of other wavelengths, it does not block the rear view. In addition, if the light 4 including information is not projected, the observer in the rear seat can see the front scene through the hologram screen 1. As the transparent substrate, a transparent resin substrate such as acrylic or polycarbonate is preferable for safety and weight reduction. Further, a configuration sandwiched between two transparent substrates is a preferable configuration in view of protection of the hologram. In addition to a resin substrate, a tempered glass substrate or a safety laminated glass in which a hologram is sealed in two glass pieces also has an excellent structure in consideration of safety. The hologram screen may be fixed to the ceiling, floor, seat back, or the like.

A hologram may be attached to a flexible film-shaped transparent substrate. Here, in FIG. 4, a film-shaped hologram screen 61 is used. The hologram screen 61 is wound around the roll 12 when not in use. The material of the film-shaped transparent substrate is preferably a transparent resin material having excellent surface smoothness and mechanical strength, such as polyethylene terephthalate. As described above, by attaching the hologram to the flexible film-shaped transparent substrate, a configuration excellent in lightness and storage property can be obtained.

For example, in FIG. 2, the hologram 10 can be attached to the transparent substrate 11 with an adhesive or an adhesive. This is the same in any of the embodiments. The adhesive or the pressure-sensitive adhesive is preferably a durable one that can be stuck with necessary strength. Further, a transparent material is preferable to prevent light loss. Further, in order to prevent light loss due to reflection on the surface of the transparent substrate, an antireflection coating may be applied to the transparent substrate. Further, a hard coating may be provided to prevent damage.

In the projection type holographic information display device for a vehicle according to the present invention, light containing information is often obliquely incident on the hologram screen 1. 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 1 is farther from the imaging optical system 33. As a result, the entire hologram screen 1 becomes out of focus, or the image is enlarged as the distance from the imaging optical system 33 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 effective to tilt the display surface of the information display source with respect to the optical axis. In order to improve the image distortion, it is effective to deform the information input to the information display source in advance so that the distortion is corrected. For example, FIG. 2 shows an example in which an information display source including a backlight 31 and a transmission type liquid crystal display element 32 is used. However, the image blur can be improved by tilting the transmission type liquid crystal display element 32.

As a type of the hologram, a volume phase type hologram such as a Lippmann type having high diffraction efficiency and strong wavelength selectivity is preferable, but other holograms can also be used. As a hologram material, a photopolymer, gelatin dichromate, a silver salt-based material, a photoresist, or the like can be used. A photopolymer having high durability and excellent mass productivity can be preferably used.

FIG. 5 is a schematic view showing an optical system for producing a light diffusion type hologram screen of one embodiment used in the present invention. This shows an optical system for producing a reflection type hologram. The hologram photosensitive material 20 is irradiated and recorded from both sides of the hologram photosensitive material 20 using divergent light as reference light and diffuse light as object light. That is, the divergent light 25
(Reference light) converts the laser light 23 into the spatial filter 22.
By diverging uniformly. Diffused light 26
The (object light) is obtained by transmitting the laser light 24 (parallel light or divergent light as long as the light is uniformly irradiated on the diffusion plate 21) through the diffusion plate 21 and uniformly diffusing the same. The distance R between the spatial filter 22 and the hologram photosensitive material 20, which is the length of the reference light, the incident angle ψ, and the incident angle φ of the object light are determined by desired conditions during reproduction (for example, when transmitted light is transmitted to an opaque portion of the vehicle). The position is appropriately determined according to the position of the projector, the position of the observer, etc. when setting the incident direction of the light in the specific wavelength range in the blocked direction.

As another method, the image of the diffusion plate may be recorded on the hologram surface by a method well known as a two-step exposure method. If a retroreflective film is juxtaposed to a hologram photosensitive material and the irradiated reference light interferes with the light transmitted through the hologram and reflected retroreflectively by the retroreflective film, a highly directional reflection is obtained. A shaped diffusion hologram is obtained. In the case of the transmission type, the reference light and the object light may be irradiated to the hologram photosensitive material from the same side. Alternatively, a large-area hologram can be exposed by sweeping a point-like or linear light beam and sequentially irradiating the hologram photosensitive material.

If the projection holographic information display device for a vehicle according to the present invention is to be displayed in color, the hologram may be multicolored. In the case of a volume type reflection hologram, since the wavelength selectivity is strong and the wavelength half width is narrow, it is preferable to use a hologram of RGB three-color exposure adapted to the wavelength of the light source.
Multiple exposures may be performed on one hologram, or holograms of single color exposure of RGB may be laminated. In the case of the transmission type, since the half width of the wavelength is wide, color display can be often performed with one hologram.

The information display source according to the present invention has a function of emitting light for displaying. A display comprising a so-called light receiving type 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 backlight comprising a halogen lamp, a metal halide lamp, a light emitting diode, a semiconductor laser, or the like can be given as an example. Alternatively, instead of using a light-receiving display element, a light-emitting display element that emits specific information as light by patterning and arranging the light source itself and a polarizer may be used. Fluorescent display tube, field emission display, plasma display, organic EL element,
Alternatively, a light emitting diode or a semiconductor laser may be used. In the case where the light receiving type display element and the backlight 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, a visual field, and the like are provided between the light receiving type display element and the backlight. A corner improving member or the like may be provided.

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

(Embodiment) An embodiment of the projection type holographic information display device for a vehicle according to the present invention will be described below with reference to FIGS. 1 and 2. The projector 3 includes a backlight 31 composed of a metal halide lamp, a 1.3 inch (about 33 mm) size transmissive liquid crystal display element 32, and an imaging optical system 33 having a focal length of 55 mm.
The light 4 emitted from the transmission type liquid crystal display element 32 is enlarged and projected on the hologram screen 1 by the imaging optical system 33,
When the distance between the imaging optical system 33 and the hologram screen 1 is about 800 mm, the projected image is about 20 inches (about 508 m).
m) It was enlarged to the size equivalent. Thus, a large-sized display was easily realized using the small-sized transmissive liquid crystal display element 32.

At this time, the light from the image forming optical system 2 to the hologram screen 3 has an incident angle of 30 ° and a light diffraction angle of 0 ° with respect to the normal to the hologram screen 3. At an incident angle of about 30 °, the blur of the projected image is at a level that is hardly noticeable, but when strictly adjusted, it becomes sharper when inclined by about 2.5 degrees. The longitudinal elongation deformation of the image was about 10%, and no particular correction was required. An acrylic photopolymer film was used as the hologram material. When forming the hologram, the object light and the reference light were exposed on the same side of the hologram photosensitive material because the hologram was a transmission type hologram. As the laser light, light having a wavelength of 532 nm of a semiconductor laser-excited solid-state laser was used. R = 800 mm, ψ =
Exposure was performed at 30 ° and φ = 0 °. The wavelength half width at the time of reproduction is about 350 nm, and almost covers the visible light region.
Information display of full color display was realized.

[0032]

According to the present invention, the hologram screen of the projection holographic information display device for a vehicle, which forms the information light to be displayed generated by the information display source on the hologram screen, is provided at the front seat and the rear seat in the vehicle. With the configuration arranged between them so that the information can be visually recognized by a rear-seat observer, a large-area information display can be provided to the rear-seat observer of the vehicle with a lightweight hologram screen. Since a transparent substrate with sufficiently high light transmittance can be used, the rear view of the driver is not obstructed, and the front view of the rear passenger is not obstructed.
In addition, a projection image with good visibility without blurring or distortion can be obtained. Also, the hologram screen can be made of a soft material that can be made into a roll, and when not in use, it can be wound up and stored small.

[Brief description of the drawings]

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

2 is an enlarged view of a main part of the projection holographic information display device for a vehicle in FIG. 1;

FIG. 3 is a schematic view of a transmissive projection holographic information display device for a vehicle according to another embodiment of the present invention.

FIG. 4 is a schematic diagram of a reflection type projection holographic information display device for a vehicle in still another embodiment according to the present invention.

FIG. 5 is a schematic view showing an optical system for producing a light diffusion hologram screen of one embodiment used in the present invention.

FIG. 6 is a schematic perspective view showing a conventional information display device for a rear seat observer.

[Explanation of symbols]

 1: Hologram screen 2: Rear seat observer 3: Projector 4: Light containing information 5, 55, 65: Transmitted light 8: Liquid crystal display element 9: Seat 10: Hologram 11: Substrate 12: Roll 20: Hologram photosensitive material 21 : Diffusion plate 22: Spatial filter 23, 24: Laser light 31: Backlight 32: Transmission display 33: Imaging optical system

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Motoji Ono 1150 Hazawa-cho, Kanagawa-ku, Yokohama-shi, Kanagawa Prefecture F-term within Asahi Glass Co., Ltd. (reference) 2H088 EA13 EA23 HA01 HA21 HA24 MA01 2K008 AA14 AA17 BB06 CC01 CC03 DD13 DD15 DD22 EE01 EE04 EE07 FF17 HH23 HH26 HH27 3D044 BA03 BA21 BA26 BB01 BC30 BD01

Claims (4)

[Claims] 1. A vehicle projection type comprising at least a light diffusion type hologram screen, an information display source for generating information to be displayed as light, and an imaging optical system for forming the light on the hologram screen. A holographic information display device for a vehicle, wherein the hologram screen is disposed between a front seat and a rear seat in a vehicle, and allows a rear seat observer to visually recognize information. 2. The information display source is arranged on a front seat side in a vehicle,
2. The projection holographic information display device for a vehicle according to claim 1, wherein the hologram screen diffracts the light containing the information in a transmissive and diffusive manner so that an observer in a rear seat can visually recognize the information. 3. The projection holographic information display device for a vehicle according to claim 1, wherein the hologram screen is attached to a transparent substrate. 4. The projection holographic information display for a vehicle according to claim 1, wherein said hologram screen can be wound up and stored in a roll shape and can be pulled out and used as needed. apparatus.