JPH06183285A - Holographic display - Google Patents

Abstract

(57) [Abstract] [Purpose] To obtain a holographic display that is compact in size for installation in a vehicle and has no aberration in a displayed virtual image. A light emitting means (1) has an image reproducing light source (2), and a light beam emitted from the image reproducing light source (2) enters a condenser lens (7) to be a light beam from a point light source (12) and a hologram (10) is enclosed. A holographic display that is illuminated toward the laminated glass 11 that is integrally held at the end of the light emitting means 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a holographic display which allows an observer to visually recognize information by using a hologram.

[0002]

2. Description of the Related Art A head-up display (hereinafter referred to as HUD) is used as a method for displaying information to a driver in a vehicle.
What is called is recently used. This is because the optical information projected from the light emitting means such as a liquid crystal display device is projected on a combiner including a half mirror,
The driver can read the information from the driving state without moving the line of sight.

Recently, attention has been paid to the use of holograms as the combiner because of the simplicity as an optical element and the abundance of added functions. Since this holographic combiner can have not only the reflection function (diffraction function) but also the lens function, etc., it diffracts optical information in the driver's visual field direction or uses other optical systems such as lenses. Instead, it is possible to form a display virtual image at an arbitrary position. Another feature is that a high-luminance display image can be obtained without impairing the foreground luminance.

FIG. 3 is a conceptual diagram showing the structure of such a vehicle-mounted HUD. Here, 31 is a driver's observation position, 32 is a combiner composed of a hologram, 33 is a light beam containing information, 34 is an image formation position of a display virtual image in a distant display, 35 is a transmissive liquid crystal display element which is a display, 36 Is a light source such as a halogen lamp, 37 is a windshield, 38 is a vehicle body, and 39 is a lens.

A light source 36 and a transmissive liquid crystal display element 35 are provided as light emitting means, and light emitted from the light source 36 passes through the transmissive liquid crystal display element 35 and is composed of a hologram provided on a windshield 37 of a vehicle. The combiner 32 is irradiated, reflected (diffracted), and visually recognized by the driver at the observation position 31. At this time, the display information is recognized by the driver as a virtual image at the position 34.

[0006]

In the above-mentioned HUD structure, the combiner and the light emitting means for irradiating the combiner with light rays are relatively distant from each other, and further, in order to assemble each separately to the vehicle body. , It is difficult to irradiate a light beam from a predetermined direction toward the combiner, and when a hologram is used as a combiner, the direction of the light beam incident on the hologram is displaced, so that the display virtual image is distorted, blurred, misaligned, etc. However, it has a drawback that the above-mentioned aberration is generated, which causes the display virtual image to be disturbed.

Further, in the above-mentioned structure, the light beam emitted from the light source is transmitted through the display body such as a liquid crystal display element which is patterned in a shape corresponding to the information to be displayed, and is irradiated onto the hologram as a light beam containing information. However, the number of parts such as the light source and the display is large, and it is difficult to put them together in a compact manner, which is not preferable in view of the vehicle space when mounted on a vehicle.

Therefore, as disclosed in US Pat. No. 4,790,613, exposure is performed so that a pattern image of information to be displayed on a hologram is recorded in advance, and this hologram is attached to a windshield of a vehicle. It is suggested to attach.

However, this US Pat. No. 4,79
Also in the configurations disclosed in JP-A Nos. 0 and 613, the hologram and the light emitting means for irradiating the hologram with light rays are relatively distant from each other. It is difficult to irradiate the light beam from the direction of, and the direction of the light beam incident on the hologram is deviated, so that the display virtual image is distorted, defocused, and misaligned.

Further, when the distance between the hologram and the light source for irradiating the light beam to the hologram is made to be short, the smaller the distance between the hologram and the light source is, the smaller the positional deviation and the mutual arrangement or arrangement of the hologram and the light source become. Distortion, blurring, and other aberrations occur in the display virtual image due to the difference in angle, and it is difficult to adjust each arrangement.

Furthermore, when exposing the hologram,
It is preferable that the light source of the light beam irradiating the hologram photosensitive material is a point light source in view of the convenience of the exposure work. In order to obtain a good display virtual image of the hologram, when reproducing the display virtual image, it is the same as during the exposure. It is required to use a point light source. On the other hand, in order to mount the light emitting means in a vehicle, it is required that the light emitting means itself be compact and small in view of the space of the vehicle. It has been difficult to obtain a light emitting means having a light source.

[0012]

The present invention has been made to solve the above-mentioned problems, and includes a light emitting means for generating a light beam,
In a holographic display, which is provided with at least a hologram arranged so as to diffract the light beam toward an observer, and a display virtual image formed by the hologram can be viewed in front of the observer, the light emitting means is an image. It has a point light source for reproduction, the light emitting means and the hologram are integrated and fixed in mutual arrangement, and the hologram is a light beam from the point light source for exposure arranged at a predetermined position in a specific direction. The present invention provides a holographic display characterized in that a pattern image of information to be displayed by being exposed by is recorded.

According to the present invention, the light emitting means has at least an image reproducing light source and a condenser lens, and a light beam emitted from the image reproducing light source is applied to the condenser lens to form a point light source for image reproduction. The present invention provides a holographic display characterized in that a light beam from a point light source for image reproduction is emitted toward a hologram.

Still further, according to the present invention, a hologram is recorded with a plurality of pattern images of information to be displayed, and each pattern image is specified by a specific point light source for exposure arranged in a specific direction. It is intended to provide a holographic display characterized by being illuminated by a light beam of a wavelength and being selectively reproduced.

Furthermore, in the present invention, the pattern image of information to be displayed recorded on the hologram is exposed by light rays of at least two colors, and the light rays from the light emitting means are irradiated to display. The present invention provides a holographic display characterized in that the color of a virtual image changes.

Furthermore, the present invention is characterized in that the pattern image of information to be displayed recorded on the hologram is exposed so that a display virtual image of a two-dimensional or three-dimensional shape is reproduced. It provides a graphic display.

Furthermore, the present invention provides a holographic display characterized in that a hologram is enclosed inside a laminated glass.

Furthermore, the present invention provides a laminated glass,
The holographic display is characterized by having an antireflection film on the mating surface of the glass plate or on the surface opposite to the mating surface.

[0019]

According to the present invention, since the hologram and the light emitting means are integrated and their mutual arrangements are fixed, aberrations such as blurring and distortion are reduced in the display virtual image visually recognized by the observer. It can be installed in the vehicle in a state. Further, by adjusting the mutual arrangement of the hologram and the light emitting means before mounting on the vehicle, aberrations such as blurring and distortion of the display virtual image can be reduced in advance.

In particular, when the holographic display of the present invention is mounted on a dashboard or the like in front of a driver of a vehicle, the size of the display is compact in order to secure the vehicle space and appearance and the front view. However, according to the present invention, it is possible to irradiate the light beam from the image reproducing light source toward the hologram as a light beam from the point light source by a small optical member such as a condenser lens. It can be provided on the dashboard or the like.

[0021]

1 is a conceptual diagram showing the basic construction of a holographic display according to the present invention. The light emitting means 1 has an image reproducing light source 2 composed of a halogen lamp, and a light beam emitted from the image reproducing light source 2 enters a condenser lens 7 to be a light beam from a point light source 12, and the light emitting means 1
Is emitted toward the hologram 10.

The hologram 10 is enclosed in a laminated glass 11, the hologram 10 is affixed to the surface of the glass substrate 8, and the surface of the hologram 10 is further provided with an antireflection film via a laminated intermediate film such as polyvinyl butyral. A cover glass plate 9 is laminated.

The laminated glass 11 is integrally held at the end of the light emitting means 1, and the point light source 12 of the light emitting means 1 is held.
The arrangement of the hologram 10 and the hologram 10 is fixed.

The light ray passing through the condenser lens 7 illuminates the surface of the hologram 10 and is reflected in the visual field direction of the observer 14. Therefore, the observer 14 is
Through this, the display virtual image 13 can be visually recognized at a predetermined position in front of the vehicle.

The condenser lens 7 receives a light beam from the image reproducing light source and produces a light beam from the point light source 12. By setting the spot size of the point light source 12 to be 3 mm or less in diameter, the condenser lens 7 can be used for a vehicle dashboard or the like. It is particularly preferable that the light emitting means 1 can be sufficiently accommodated and the diameter is 1 mm or less. By appropriately selecting and using the numerical aperture of the condenser lens 7, a point light source 12 having a desired spot size can be obtained, and even when the size of the light emitting means 1 is limited, the light emitting means is provided. It is possible to reduce the blur and distortion of the display virtual image 13 while making the distance from 1 to the hologram 10 a desired distance.

Further, in this embodiment, the image reproducing light source 2 is used.
The collimator lens 4 is interposed between the condenser lens 7 and the condenser lens 7 to shorten the distance between the image reproducing light source 2 and the condenser lens 7. However, this embodiment is not particularly limited, and the condenser lens 7 The collimator lens 4 and the collimator lens 4 may be integrated (for example, an objective lens of a microscope).

Further, as a light source for image reproduction, the lamp filament is small (preferably 1 mm × 1 mm × 1 mm).
(Below) If you use a shape, you do not need to form a point light source using a lens system, you can form a desired display virtual image only by diverging light from the lamp, the number of parts is small, compact and simplified light emission It can be a means.

In addition, as shown in FIG. 1, the light emitting means is provided with an elliptic mirror 3, a color filter 5, a plane mirror 6 and the like, and the light emitting means in the present invention is provided with an optical member such as a concave mirror. Alternatively, various optical members may be provided in order to prevent color blurring of the display virtual image and to obtain a desired size of the light emitting means.

FIG. 2 is a conceptual diagram for explaining the hologram exposure method used in the present invention. Argon ion laser beam emitted from the hologram exposure light source 20,
The light is returned to a predetermined optical path by a mirror 21 and the like, and is split into two by a beam splitter 22. One of the two divided light beams is a light beam from a point light source for exposure, and the mirror 23
The hologram photosensitive material 27 is irradiated as reference light through the or lens 24. On the other hand, a positive type in which a predetermined pattern of information to be displayed is formed between the diffusion plate 25 and the hologram photosensitive material after being irradiated on the diffusion plate 25 via the mirror 23 and the lens 24, or After passing through the negative type mask 26, the hologram photosensitive material 27 arranged at a distance L2 is irradiated as object light. In addition,
In the present embodiment, L2 = 300 mm to 2000 mm, but it is not limited to this.

As the reference light, a laser beam is once condensed by a lens 24 to form a light beam from a point light source for exposure, and the hologram photosensitive material 27 is irradiated with a spherical wave.
The distance between this point light source for exposure and the hologram photosensitive material is L
1, and by arranging the point light source for image reproduction of the light emitting means according to the present invention and the hologram surface at L1 in the same manner,
A predetermined reproduced image is obtained at the position L2 from the hologram surface. In this example, L1 = 50 mm to 300 m
However, it is not limited to this.

The exposure method shown in FIG. 2 is a method of forming a reflection hologram, and the reference light and the object light are irradiated so as to face both sides of the hologram photosensitive material surface. In the case of creating, the reference light and the object light may be irradiated from the same surface side of the hologram photosensitive material surface.

Although the holographic display shown in FIG. 1 uses a reflective hologram, the holographic display of the present invention may use a transmissive hologram produced by the above-mentioned exposure method.
In this case, the hologram and the light emitting means are arranged in this order from the observer side, and the light beam emitted from the point light source of the light emitting means transmits (refracts) through the hologram and is diffracted toward the observer, and the display virtual image is in front of the observer. Is imaged.

Here, the information to be displayed in the present invention is appropriately selected according to its display application, and includes a vehicle warning light, a blinker, a side light, a corner marker,
Examples include speedometers. The observer is mainly the driver of the vehicle, and may include passengers other than the passenger seat, and all of them.

The hologram is usually several tens of mm square to several hundreds m.
It has an area of about m square and a thickness of about several tens of μm, and has a light diffraction function. As this hologram, a Lippmann type (reflection type) is relatively easy to use, but other holograms can be widely used. As the hologram material, various photosensitive materials such as photopolymer, dichromated gelatin, and silver salt can be used.

The peak wavelength of the diffraction intensity of the hologram can be made to substantially match the peak wavelength of the intensity of the light source.
It is preferable for improving the diffraction efficiency. Further, it may be formed by performing multiple exposure with light having different properties, or may be formed by stacking a plurality of holograms exposed by different light.

In the present invention, such a hologram is integrally attached to a light emitting means provided with a light source for image reproduction, and is placed in the vicinity of the windshield of a vehicle within a natural visual field of a driver as an observer. It is preferably located and preferably installed in the instrument panel or dashboard of the vehicle.

From the viewpoint of protection from external factors, the hologram is preferably used by being enclosed inside the laminated glass. Laminated glass is obtained by laminating and adhering a synthetic resin film such as a polyvinyl butyral film and a polyurethane film on at least one glass, and examples of its form include:
There are glass plate / synthetic resin film, glass plate / synthetic resin film / glass plate, glass plate / synthetic resin film / glass plate / synthetic resin film, glass plate / synthetic resin film / synthetic resin film, and the like. The hologram may be enclosed in the boundary between these glass plates or the synthetic resin film or inside the synthetic resin film. The glass plate on which the hologram is mounted may be colored or may be provided on its surface with an antireflection film, black ceramics, a heat ray reflective film, or the like. Further, since the glass plate is less likely to be thermally deformed, it is most suitable for holding the hologram, but in view of cost, a plastic resin may be used instead of the glass plate.

The image reproducing light source in the present invention includes a tungsten lamp, a halogen lamp, a metal halide lamp, an LED, a fluorescent display tube, a hot cathode discharge tube, a cold cathode discharge tube, an LD (laser diode), etc., and these emit light. If necessary, optical components such as mirrors, prisms, lenses, color filters and polarizing elements are arranged in the optical path until the light is projected on the hologram, and a point light source is formed in a predetermined optical path. Good.

[0039]

According to the present invention, since the hologram and the light emitting means are integrated and their mutual arrangements are fixed, aberrations such as blurring and distortion are reduced in the display virtual image visually recognized by the observer. It is possible to obtain a holographic display that can be mounted on a vehicle in a fixed state.

Further, by adjusting the mutual arrangement of the hologram and the light emitting means before mounting on the vehicle, aberrations such as blurring and distortion in the display virtual image can be reduced in advance, and this adjustment can be performed before mounting on the vehicle. Therefore, the adjustment work can be easily performed.

In particular, when the holographic display of the present invention is mounted on a dashboard or the like in front of a driver of a vehicle, the size of the display is ensured in order to secure the vehicle space, appearance, and front view. However, according to the present invention, the light beam from the image reproducing light source can be directed to the hologram as a light beam from the image reproducing point light source by a small optical member such as a condenser lens. Can be installed in a vehicle in a very compact manner.

[Brief description of drawings]

FIG. 1 is a conceptual diagram showing a basic configuration of a holographic display of the present invention.

FIG. 2 is a conceptual diagram illustrating a hologram exposure method used in the present invention.

FIG. 3 is a conceptual diagram showing a configuration of a conventional HUD.

[Explanation of symbols]

 1: Light emitting means 2: Light source for image reproduction 10: Hologram 11: Laminated glass 13: Displayed virtual image 14: Observer 20: Light source for hologram exposure 27: Holographic photosensitive material

Claims (7)

[Claims] 1. A light emitting means for generating a light beam and a hologram arranged so as to diffract the light beam toward an observer, and a display virtual image formed by the hologram can be visually recognized in front of the observer. In the holographic display, the light emitting means has a point light source for image reproduction, the light emitting means and the hologram are integrated and fixed to each other, and the hologram has a predetermined direction in a specific direction. A holographic display characterized in that a pattern image of information to be displayed by being exposed by a light beam from a point light source for exposure arranged at a position is recorded. 2. The light emitting means has at least an image reproducing light source and a condenser lens, and the condenser lens is irradiated with a light beam emitted from the image reproducing light source to form a point light source for image reproduction, The holographic display according to claim 1, wherein the light beam from the point light source is emitted toward the hologram. 3. A hologram is recorded with a plurality of pattern images of information to be displayed, and each pattern image is irradiated with a light beam of a specific wavelength from an exposure point light source arranged in a specific direction. 3. The holographic display according to claim 1, wherein the holographic display is played back and selectively reproduced. 4. The pattern image of information to be displayed recorded on the hologram is exposed by light beams of at least two colors, and the color of the display virtual image is changed by irradiation of light beams from the light emitting means. The holographic display according to claim 1, wherein 5. The pattern image of information to be displayed recorded on the hologram is exposed so that a display virtual image having a two-dimensional or three-dimensional shape is reproduced. Any holographic display. 6. The holographic display according to claim 1, wherein the hologram is enclosed inside a laminated glass. 7. The holographic display according to claim 6, wherein the laminated glass has an antireflection film on the laminated surface of the glass plate or on the surface opposite to the laminated surface.