JP4437566B2 - Illuminated hologram display device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an illuminated hologram display device, and more particularly to a hologram display device that incorporates an illumination light source and can be observed in a dark place.
[0002]
[Prior art]
Conventionally, volume holograms are known as holograms that can be observed under white light such as room illumination light or natural light. Among them, reflection type holograms are particularly known as Lippmann holograms.
[0003]
Such volume holograms are capable of displaying color images by superimposing RGB multiple recording or single color holograms, and have recently attracted attention as graphic art holograms.
[0004]
[Problems to be solved by the invention]
When observing a volume hologram that can be observed with such white light, the hologram has an illumination light incident angle dependency determined by the recording conditions, so the image may appear blurred or change its color depending on the observation angle. There is a problem.
[0005]
The present invention has been made in view of the above-described problems of the prior art, and its purpose is to provide an illuminating device that can receive illumination light at a predetermined incident angle and is integrated with a volume hologram so that it can be clearly seen in any environment. It is another object of the present invention to provide a hologram display device that can observe a bright reproduced image.
[0006]
[Means for Solving the Problems]
The illuminated hologram display device of the present invention that achieves the above object comprises a reflective volume hologram that records an image, a light guide plate disposed in front of the hologram, and a light source disposed in front of the side surface of the light guide plate, The light guide plate guides the illumination light from the light source into the light guide plate by total reflection, and emits light guided by a microprism provided on one surface as illumination light at a predetermined emission angle from the surface of the light guide plate. The reflective volume hologram is illuminated with illumination light emitted from the light guide plate, and the diffracted light diffracted from the reflective volume hologram can be observed through the light guide plate. It is what.
[0007]
Another illuminated hologram display device of the present invention comprises a transmission-type volume hologram on which an image is recorded, a light guide plate disposed on the back surface thereof, and a light source disposed on the front side of the light guide plate. The light plate guides the illumination light from the light source into the light guide plate by total reflection, and emits the light guided by the microprism provided on one surface as illumination light from the surface of the light guide plate at a predetermined emission angle. The transmissive volume hologram is illuminated with illumination light emitted from the light guide plate, and the diffracted light diffracted from the transmissive volume hologram can be observed.
[0008]
In the present invention, since the illumination light incident on the volume hologram is incident from the light guide plate at a predetermined incident angle, the reproduced image does not blur or change color, and the reproduced image is clear and bright under any environment. Can be observed.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Examples of the illuminated hologram display device of the present invention will be described below.
FIG. 2 is a diagram showing an arrangement for photographing a Denniske-type reflective volume hologram in a volume hologram. A volume hologram photosensitive material 1 made of a photopolymer or the like is placed in front of a subject O to be photographed. When the light 2 having a predetermined wavelength is incident at a constant incident angle θ from the photosensitive material 1 side, the light 2 passes through the photosensitive material 1 and illuminates the subject O. By reflecting the object light 3 reflected and scattered by the subject O and incident light 2 incident from the back side of the light-sensitive material 1 in the light-sensitive material 1, a reflection hologram in which the image of the subject O is recorded is recorded. This reflection type volume hologram is assumed to be 10 (FIG. 1). In order to record a color image of the subject O, the wavelength of the illumination light 2 is sequentially changed to wavelengths of two or more color regions, and multiple recording is performed in one photosensitive material 1 or separate photosensitive materials 1. What is necessary is just to record inside and to superimpose those monochromatic holograms.
[0010]
FIG. 1 is a cross-sectional view of an embodiment of an illuminated hologram display device according to the present invention for displaying a volume hologram 10 photographed in this way. This display device is disposed in a case 11 whose front surface is open. A volume hologram 10, a light guide plate 12 called a front light, a line light source 13 disposed on the side of the light guide plate 12, and a reflecting mirror 14 that reflects light from the line light source 13 are disposed in front of the volume hologram 10. ing.
[0011]
Here, the light guide plate 12 is provided with a number of microprisms 16 having a sawtooth cross section on the front surface 15, and the illumination light 18 from the line light source 13 disposed in front of the side surface of the light guide plate 12 is received in the light guide plate 12. And has a function of totally reflecting light incident on the slope of the microprism 16 and emitting it as illumination light 19 from the rear surface 17 of the light guide plate 12 at a predetermined emission angle θ. The emission angle θ can be arbitrarily set depending on the design of the microprism 16 (see, for example, “Monthly Display” June 1998, pages 54 to 57).
[0012]
With such an arrangement, the illumination light 19 from the light guide plate 12 is incident on the volume hologram 10 at a predetermined incident angle θ, and diffracted light 20 for reproducing the recorded image is generated on the reflection side. Since the diffracted light 20 passes through the light guide plate 12 and enters the observer's eye E positioned in front of the light guide plate 12, the observer observes the image O ′ of the subject O recorded in the volume hologram 10.
[0013]
According to such a configuration, since the illumination light 19 incident on the volume hologram 10 is incident at a predetermined incident angle θ, the reproduced image is not blurred or the color is not changed, and the reproduction is clear and bright under any environment. An image can be observed.
[0014]
The above is a case where the hologram 10 is a reflection type. However, in the case of a transmission type volume hologram, the observation direction may be on the opposite side to FIG. 1, that is, on the lower side of the figure. Since the light 20 is not directed to the light guide plate 12, it can be observed by being directly incident on the eye E.
[0015]
As described above, the illuminated hologram display device of the present invention has been described based on the embodiments. However, the present invention is not limited to these embodiments, and various modifications can be made. The volume hologram 10 and the light guide plate 12 may be in close contact with each other without being separated from each other.
[0016]
【The invention's effect】
As is apparent from the above description, according to the illuminated hologram display device of the present invention, the illumination light incident on the volume hologram is incident at a predetermined incident angle from the light guide plate, so that the reproduced image is blurred or the color changes. There is nothing, and a clear and bright reproduced image can be observed under any environment.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of one embodiment of an illuminated hologram display device of the present invention for displaying volume holograms.
FIG. 2 is a view showing an arrangement for photographing a Denniske type reflection type volume hologram;
[Explanation of symbols]
O ... Subject O '... Reproduced image 1 of the subject ... Sensitive material 2 for volume holograms ... Incoming light 3 ... Object light (reflection scattering)
DESCRIPTION OF SYMBOLS 10 ... Reflective volume hologram 11 ... Case 12 ... Light guide plate 13 ... Line light source 14 ... Reflection mirror 15 ... Front surface 16 of a light guide plate ... Micro prism 17 ... Rear surface 18 of a light guide plate ... Illumination light 19 ... Illumination light 20 ... Diffracted light

Claims (2)

A reflection type volume hologram recording an image, a light guide plate disposed in front of the hologram, and a light source disposed in front of the side surface of the light guide plate, wherein the light guide plate transmits illumination light from the light source in the light guide plate The light guided by the microprism provided on one surface of the light is emitted from the surface of the light guide plate as illumination light at a predetermined emission angle, and the illumination light emitted from the light guide plate An illuminated hologram display device configured to illuminate the reflective volume hologram and to observe a reproduced image diffracted from the reflective volume hologram through the light guide plate. A transmission type volume hologram recording an image, a light guide plate disposed on the back surface thereof, and a light source disposed in front of the side surface of the light guide plate, wherein the light guide plate transmits illumination light from the light source in the light guide plate The light guided by the microprism provided on one surface of the light is emitted from the surface of the light guide plate as illumination light at a predetermined emission angle, and the illumination light emitted from the light guide plate An illuminated hologram display device configured to illuminate the transmission volume hologram and to observe a reproduced image diffracted from the transmission volume hologram.

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