JPH0796772A - Holographic display - Google Patents

Abstract

(57) [Summary] [Structure] Outside the first reflective hologram 3,
Of the light incident from the outside of the vehicle, the incident angle is θ ₁ , and the wavelength band is the wavelength band of the light reflected and diffracted by the first reflective hologram 3.
The reflection hologram 13 of FIG. 2 is arranged, and the light emitted from the light emitting display means 1 toward the first reflection hologram 3 is observed by the first reflection hologram 3 at the diffraction angle θ ₂ by the observer 5.
A holographic display that diffracts and reflects toward. [Effect] It is possible to obtain a holographic display that does not impair the forward visibility without allowing the observer to visually recognize the ghost.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a holographic display, and more particularly to a holographic display for projecting information necessary for a driver such as speed through a windshield of a vehicle such as a vehicle or an aircraft.

[0002]

2. Description of the Related Art A head-up display (hereinafter referred to as HUD) is used as a method of displaying information to a driver in a vehicle.
Has been proposed. This is because the optical information projected from the light emitting display means such as a liquid crystal display device is displayed on a combiner including a half mirror and a hologram provided on the windshield so that the driver hardly moves his or her line of sight from the driving state. The information can be read.

In particular, the one using a hologram as a combiner is capable of diffracting optical information toward a driver and forming an image at an arbitrary position, and it is possible to enhance the brightness without impairing the foreground brightness. It is effective as a combiner for HUD because it has a characteristic that a display virtual image of brightness can be obtained.

[0004]

FIG. 5 shows the above-mentioned HU.
FIG. 5 is a conceptual diagram showing an example of D, in which light emitted from the light emitting display means 51 is a windshield 5 made of laminated glass of a vehicle.
The light enters the hologram 53 enclosed in 4 at an incident angle θ ₁ , is reflected and diffracted toward the observer 55 at a diffraction angle θ ₂ , and the observer 55 visually recognizes the displayed virtual image.

The incident angle and the diffraction angle shown below indicate the incident angle at which the center of the hologram is connected from the light source or the light emitting display means to be incident, and the diffraction angle at which the observer or the like is connected from the center of the hologram to diffract. .

However, in such a HUD, when the light incident from the light source 52 outside the vehicle toward the windshield 55 at the incident angle θ ₁ passes through the hologram 53, this light is reflected by the back surface of the windshield 54 on the inside surface of the vehicle. Thus, the light enters the hologram 53 at an incident angle θ ₁ . After that, the hologram 5 is reflected by this back surface reflection.
Of the light incident on the hologram 3, the light in the specific wavelength range, that is, the wavelength range specified during the exposure of the hologram 53 is the hologram 5
The light is reflected and diffracted at a diffraction angle θ ₂ by 3 and is irradiated toward the observer 55.

In such a case, the light from the light source 52 outside the vehicle is dispersed, and the light in the specific wavelength range and the extra light different from the normal white transmitted light are radiated toward the observer 55. 55 has a defect that the ghost is visually recognized, and the safety of the front view is impaired.

An object of the present invention is to solve the above-mentioned drawbacks of the prior art, and to provide a holographic display which has not been heretofore known.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and a light emitting display means for generating light containing information and the light is diffractively reflected toward an observer. As described above, at least the first reflection-type hologram arranged on the windshield of the vehicle and the second reflection-type hologram arranged outside the first reflection-type hologram on the vehicle exterior side, and the display virtual image of the light-emitting display means are provided. In the holographic display which allows the observer to visually recognize, the first reflection hologram diffracts the light incident from the light emitting display means at the incident angle θ ₁ toward the observer at the diffraction angle θ ₂ . Second
In the reflection hologram, the light having the substantially same wavelength range as the light from the light emitting display means and having an incident angle of approximately θ ₁ incident from the vehicle outer side toward the second reflection hologram is transmitted to the vehicle outer side. A holographic display characterized by diffracting toward.

Further, the present invention provides a light emitting display means for generating light containing information, a reflection type hologram arranged on a windshield of a vehicle so as to reflect and diffract the light toward an observer, and a reflection hologram. In the holographic display, which is provided with at least a transmission type hologram arranged on the outer side of the vehicle with respect to the reflection type hologram, so that the display virtual image of the light emitting display means can be visually recognized by an observer, the reflection type hologram is incident from the light emission display means. Light incident at an angle θ ₁ is reflected by the diffraction angle θ ₂
The diffraction angle of the transmission hologram is substantially the same as that of the light from the light emitting display means, and the incident angle of incidence from the outside of the vehicle toward the transmission hologram is approximately θ.
₁ is a light, there is provided a holographic display, wherein the transmitting diffracting toward the interior side in the theta ₁ and different angles.

[0011]

In the holographic display according to the present invention, the second reflection hologram causes the light having substantially the same wavelength as the light emitted from the light emitting display means to enter the windshield from the light source outside the vehicle at an incident angle of θ _1. Since the light in the area is reflected and diffracted toward the outside of the vehicle, the above-described light from outside the vehicle does not reach the inside surface of the windshield of the vehicle.

Therefore, it is possible to eliminate the light in the substantially same wavelength range as the light from the light emitting display means which is incident on the first reflection hologram at the incident angle θ _{1 and} which is caused by the back surface reflection on the inside surface of the windshield glass. Therefore, the ghost due to the back surface reflection can be eliminated.

Further, the holographic display of the present invention uses the transmission hologram to transmit light from the light source outside the vehicle toward the windshield at an incident angle of θ ₁ at a wavelength range substantially the same as that of the light from the light emitting display means. Light is transmitted and diffracted so that the incident angle on the inside surface of the vehicle is different from θ ₁ .

Therefore, the light in the substantially same wavelength range as the light from the light emitting display means incident toward the first reflection hologram, which is generated by the back surface reflection on the vehicle interior side surface of the windshield, is incident at an angle different from θ ₁ . It is possible to eliminate the ghost due to the back surface reflection.

[0015]

Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 1 is a conceptual diagram showing an example of a holographic display of the present invention. The first reflective hologram 3 is enclosed in a windshield 4,
It was previously exposed so as to reflect the light in a specific wavelength range incident at θ ₁ at a diffraction angle θ ₂ .

A light emitting display means 1 is provided below the windshield 4, and the light emitting display means 1 displays the information of the above-mentioned specific wavelength region at an incident angle θ ₁ toward the first reflection hologram 3. Emits light including. The light emitted from the light emitting display means 1 toward the first reflective hologram 3 is reflected and diffracted toward the observer 5 at the diffraction angle θ ₂ by the first reflective hologram 3, and the observer 5 displays it. You can see the virtual image.

A second reflection type hologram 13 is arranged outside the first reflection type hologram 3 on the vehicle side. The second reflection hologram 13 includes a wavelength range of light that is reflected and diffracted by the first reflection hologram 3 having an incident angle of θ ₁ and a wavelength range of the light incident from the outside of the vehicle. The exposed light is exposed so as to be reflected and diffracted toward the outside of the vehicle.

FIG. 4 is a conceptual diagram showing an example of an exposure method for producing a reflection hologram according to the present invention. Light sources 42 are provided on both sides of a hologram photosensitive material 41, and α ₁ from both sides of the hologram photosensitive material 41. , Α ₂ is used for the exposure.

The first reflection type hologram 3 is obtained by performing exposure with α ₁ = θ ₁ and α ₂ = θ ₂ by the above-mentioned exposure method. The second reflection hologram 13 is α ₁ = θ by the exposure method described above.
It is obtained by performing exposure as ₁ (note that α ₂ is not particularly limited).

Thus, the light incident from the outside of the vehicle is
It is not reflected and diffracted by the first reflection hologram due to the back surface reflection of the windshield.

In the case of a general passenger car, the line of sight for the observer to visually recognize the displayed virtual image is tilted downward from the horizontal direction by about 0 to 5 °. Therefore, when the windshield is attached to the vehicle body at an angle of 30 °, the diffraction angle (ie, the light from the light emitting display means is reflected and diffracted toward the observer from the combiner (first reflection hologram). θ ₂ ) is 60 ~
It becomes 65 °. On the other hand, the position at which the light emitting display means is provided inside the vehicle is limited to some extent in view of the vehicle space, and the incident angle θ ₁ incident from the light emitting display means to the first reflection hologram is about 25 to 45 °. preferable.

In such a case, the second reflection type hologram is exposed so that the incident light is reflected and diffracted at an incident angle substantially equal to the incident angle θ ₁ , that is, at an incident angle of about 25 to 45 °. The diffraction angle of the second reflection hologram is 1
About 0 to 30 ° is preferable.

(Embodiment 2) FIG. 2 is a conceptual diagram showing another example of the holographic display of the present invention.
The structure is the same as that of the first embodiment except the structure of the reflection hologram.

The second reflection type hologram 23 is formed by laminating three reflection type holograms 23a, 23b and 23c. The reflection type hologram 23a is arranged on the vehicle outer side than the first reflection type hologram 3, and of the light incident from the outside of the vehicle, the incident angle is θ ₁ , and the wavelength range is the first reflection type hologram 3. The light including the wavelength range of the light reflected and diffracted by is exposed so as to be reflected and diffracted toward the outside of the vehicle.

The reflection type holograms 23b and 23c reflect and diffract light in a wavelength range of a color which is a complementary color of the light in the wavelength range reflected and diffracted by the reflection type hologram 23a, and moreover, enter substantially the same as the reflection type hologram 23a. It was exposed so that angular light was reflected and diffracted at substantially the same angle. In this way, the light reflected by the second reflective hologram 23 to the outside of the vehicle does not have a specific color and is visually recognized as white light on the outside of the vehicle.

At this time, the reflection holograms 23a, 23b, 23c
There is no limitation on the stacking order of, and each may not be joined. Furthermore, these reflection holograms 23 are
Multiple exposure was performed to correspond to the light in the above wavelength range 1
It may be a sheet.

For example, when the first reflection type hologram is one that reflects and diffracts light in the green wavelength range, the reflection type holograms 23a, 23b, 23c can emit light in the green, red and blue wavelength ranges. It reflects and diffracts. The first reflection type hologram is also a layer formed by stacking three sheets exposed by light of wavelength regions corresponding to a plurality of colors as in the second reflection type hologram, or by multiple exposure to one sheet. Well,
This also applies to the other embodiments.

(Embodiment 3) FIG. 3 is a conceptual view showing another example of the holographic display of the present invention, in which the reflection hologram 33 is enclosed in the windshield 4 and is incident beforehand at θ _1. It was exposed so as to reflect light of a specific wavelength range coming from it at a diffraction angle θ ₂ .

A light emitting display means 1 is provided below the windshield 4, and the light emitting display means 1 emits light including the above-mentioned information in a specific wavelength range at an incident angle θ ₁ toward the reflection hologram 33. Emit. The light emitted from the light emitting display means 1 toward the reflection hologram 33 is reflected and diffracted toward the observer 5 at the diffraction angle θ ₂ by the reflection hologram 33, and the observer 5 can visually recognize the displayed virtual image. it can.

On the outer side of the vehicle than the reflection hologram 33,
A transmission hologram 36 is arranged. The transmission hologram 36, among the light incident from the outside of the vehicle, the light having a wavelength range of light that is reflected and diffracted by the incident angle theta _1, the reflection type hologram 33 which wavelength region described above, theta ₁ and It was exposed so as to be transmitted and diffracted toward the inside surface of the windshield glass at different angles of diffraction.

This transmission hologram 36 is provided with a light source on one side of the hologram photosensitive material, and is exposed from one side of the hologram photosensitive material at incident angles of α ₃ and α ₄ , respectively. In this case, It is obtained by performing exposure with α ₃ = θ ₁ and α ₄ ≠ θ ₁ (not shown).

The light from the light source outside the vehicle that has passed through the transmissive hologram is transmitted and diffracted at an angle different from θ _1. Of this diffracted light, windshield glass other than the back surface reflection by the windshield is used. In order to prevent the light transmitted through the beam from reaching the observer, the diffraction angle of the transmission hologram is −
5 to + 20 ° is preferable, and a range of 0 to 10 ° is particularly preferable.

The information to be displayed in the present invention is appropriately selected according to its display application, and examples thereof include a speedometer of a vehicle, a tachometer, and various warning lamps. The display distance can be set according to the urgency or need of the.

The observer is mainly the driver of the vehicle, but can also include passengers such as the passenger seat and all passengers.

The hologram is usually several 10 mm square to several 1
It has an area of about 00 mm square and a thickness of about several tens of μm, and has a light diffraction function. As the hologram material, various photosensitive materials such as polyvinyl carbazole, gelatin dichromate, photoresist, photopolymer, and silver salt can be used. From the viewpoint of durability, photopolymer is preferable.

When the windshield is provided with the first reflection hologram, for example, the surface of the windshield (the outer surface of the vehicle).
Although it may be provided on the inside surface of the vehicle, it is preferably used by being enclosed inside a windshield which is a laminated glass in view of protection of the reflection hologram. In this case, it is preferable that the second reflection type hologram or the transmission type hologram is also enclosed inside the laminated glass together with the first reflection type hologram. Also, these holograms
Although it is not particularly limited whether they are bonded to each other or separated from each other, it is preferable that they are bonded to each other from the viewpoint of easy encapsulation in the laminated glass. If these holograms are placed on the inside of the windshield glass,
By disposing a transparent protective film on the hologram, the hologram can be protected. In this case,
Back reflection will be caused by this film.

The light emitting display means in the present invention has a function of emitting light to display, and a hot cathode tube (HC) is attached to a display body composed of a so-called light receiving display element such as a liquid crystal display element.
T), a fluorescent display tube (VF), a halogen lamp, an LED, or the like, which emits light emitted from a light source, or may have these functions together.

As the liquid crystal display element, a transmission type twisted nematic type liquid crystal display element, a super twisted nematic type liquid crystal display element or the like can be preferably used. Also,
Apart from that, instead of using the light receiving display element, the light source itself may be patterned and arranged to generate specific information as light. In the case where the light source is used together with the light receiving display element, an appropriate light beam collimating means such as a lens system or an appropriate light guiding means such as a light guide plate is arranged between the light receiving display element and the light source. Good.

[0040]

According to the present invention, the reflection hologram, which is arranged on the windshield and reflects and diffracts the light from the light emitting display means toward the observer, the backside reflected light of the windshield outside the vehicle is θ _1. Since the light is not incident at the incident angle of 1, the ghost can be seen by the observer, and a holographic display that does not impair the forward field of view can be obtained.

Particularly, by making the second reflection hologram on the vehicle outer side than the first reflection hologram three holograms or the multiple-exposed hologram, the light from the outside of the vehicle is reflected by the second reflection hologram. Even when it is reflected and diffracted to the outside of the vehicle by the type hologram, the diffracted light can be made into white light, and the appearance of the combiner can be improved.

[Brief description of drawings]

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

FIG. 2 is a conceptual diagram showing an example of a holographic display of the present invention.

FIG. 3 is a conceptual diagram showing an example of a holographic display of the present invention.

FIG. 4 is a conceptual diagram showing an example of an exposure method for creating a reflection hologram according to the present invention.

FIG. 5 is a conceptual diagram showing an example of a conventional HUD.

[Explanation of symbols]

 1: Light emitting display means 3: First reflection type hologram 4: Windshield 5: Observer 13, 23: Second reflection type hologram 33: Reflection type hologram 36: Transmission type hologram 41: Hologram photosensitive material 42: Light source

Claims (2)

[Claims] 1. A light emitting display means for generating light containing information,
A first reflective hologram arranged on the windshield of the vehicle so as to diffract the light reflectively toward the observer;
In the holographic display, at least a second reflection type hologram arranged outside the reflection type hologram is provided so that a virtual image displayed by the light emitting display means can be visually recognized by an observer. Is the light incident from the light emitting display unit at an incident angle θ ₁ .
The second reflection hologram is diffracted toward the observer at a diffraction angle θ ₂ , and the second reflection hologram is incident from the outside of the vehicle toward the second reflection hologram in the substantially same wavelength range as the light from the light emitting display means. A holographic display that diffracts light with an incident angle of approximately θ ₁ toward the outside of the vehicle. 2. A light emitting display means for generating light containing information,
The light-emitting display includes at least a reflection hologram arranged on the windshield of the vehicle so as to diffract the light toward the observer in a reflective manner, and a transmission hologram arranged outside the reflection hologram. In a holographic display in which a display virtual image of the means can be visually recognized by an observer, the reflection hologram diffracts light incident from the light emitting display means at an incident angle θ ₁ toward the observer at a diffraction angle θ _2. , The transmissive hologram has the same wavelength range as that of the light from the light emitting display means, and the incident light incident from the outside of the vehicle toward the transmissive hologram at an incident angle of approximately θ ₁ is
A holographic display characterized by transmitting and diffracting toward the inside of the car at an angle different from ₁ .