JPS5916265B2 - Color hologram photographing method and device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to color holography using image holography.

Fresnel type holography and its color holography are described in detail in Japanese Patent Publication No. 43-4303.

The color holography described in this publication separates colors using a three-color laser light source, changes the incident direction of reference light for each color, and performs multiplex recording to obtain a hologram. A hologram with an angle of incidence of 5
It illuminates to obtain a reproduced image. However, the disadvantage of this conventional color holography is that it requires three-color laser beams for photographing and reproduction, making it expensive and requiring a large-scale apparatus.

There is also a method of photographing color holograms using the Lippmann method, but this method also has disadvantages such as requiring three-color lasers, being susceptible to emulsion shrinkage, and having low diffraction efficiency. Ta. The present invention relates to a novel color holography, in which 5 high-coherence beams generated from a laser light source are split into a reference beam and a signal beam by a beam splitter, and the reference beam is split into a reference beam and a signal beam by a mirror and a magnifying lens. etc., onto the surface of the photosensitive plate at a predetermined angle of incidence, and on the other hand, the signal light beam is expanded onto a diffuser plate through a mirror, a magnifying lens, etc., and illuminates a pre-prepared decomposition positive. In order to form a positive image on the surface of the photoreceptor, a photographing lens with a relatively large diameter is used, and a mask with a plurality of holes is arranged in front of the lens. After recording one color by opening a hole and exposing it to light,
Place the separation positives of the other colors in alignment with that image,
Exposure is performed through holes at other positions to record other colors, and after recording multiple colors as in this example, the photosensitive plate is developed to obtain a multi-recorded image hologram. When reproducing this hologram, parallel light obtained from a white light source such as a xenon lamp is used to illuminate the hologram at the incident angle of the reference light at the time of photographing, and a projection lens is placed in front of the hologram. A color image is created by placing a mask equipped with a color filter corresponding to the color in front of the projection lens at a position that takes into account light dispersion relative to the position of the hole in the mask used during photographing, and projecting it onto a matte screen, etc. This invention relates to a holographic device that is characterized by the reproduction of .

To explain the present invention in detail with reference to the drawings, FIG. 1 shows an optical system for photographing, in which a beam L-1 generated from a light source 1 such as a laser light source that generates a beam with high coherence is irradiated with a shutter. 2 to a beam splitter 3, and the beam splitter 1 splits the light into a reference light beam L-2 and a signal light beam L-3.

As light source 1, He-Ne laser 6328λ, Ar
A 5145λ, 4880λ laser light source or the like is suitable. The beam splitter 13 is a half mirror, and generally the best hologram can be obtained when the reference light and the signal light reaching the photosensitive plate 7 have approximately the same intensity. The beam L-1 is divided into appropriate light quantity ratios in consideration of loss. The reference light beam L-2 is directed by the mirror 4 so as to be incident on the photosensitive plate 7 at a predetermined angle of incidence θ.

Appropriately, this angle of incidence θ is around 40 degrees. The directed beam L-2 is expanded by a magnifying lens 5 and illuminates the entire surface of a photosensitive plate 7 through a pinhole in a pinhole plate 6.
This magnifying lens 5 is a convex lens with a short focal length, and magnifies the parallel beam L-2 onto the photosensitive plate 7 to illuminate it.

The pinhole plate 6 is a plate having a pinhole of about 10 μm in diameter, and is arranged so that the pinhole is located at the focal point of the magnifying lens 5 to cut out the poor quality beam near the outer periphery of the beam L-2. On the other hand, beam L-3 for signal light
is directed to the front of the photosensitive plate 7 by a mirror 17, and is magnified through a magnifying lens 8 and a pinhole plate 9 to a diffuser plate 10, and a pre-prepared decomposed positive 11 placed in front of the diffuser plate 10 is shown.
to illuminate.

This magnifying lens 8 and pinhole plate 9 are the magnifying lens 5
, has the same effect as the pinhole plate 6, and the diffusion plate 1
0 is a translucent screen such as ground glass. Also, the separation positive 11 separates the original image to be recorded into three primary colors of light (red, green,
For example, an arbitrary one of the transmission type positives that have been decomposed into (blue), for example, the red decomposed positive 11-R.

A photographing lens 15 and a mask 12 for forming an image of the decomposed positive 11 on the surface of the photosensitive plate 7 are arranged between the decomposed positive and the photosensitive plate. For example, the mask 12 has holes 13-R and 13-R with a diameter of about 4 mm.
Three holes 3-G and 13-B are drilled in a straight line at 6 mm intervals (see Figure 2). Hole 13-G, l
3-R is closed by light shielding plates 14-G and 14-B.

Here, when photographing a green decomposition positive, only the hole 13-G is opened, and when photographing a blue decomposition positive, only the hole 13-B is opened.

Further, the photographing lens 15 is a compound lens with a small aperture that can cover the width of the hole 13 and has a focal length of approximately 50 m7n.

The photosensitive plate 7 used in the present invention is a high-resolution film or a dry plate used for ordinary holograms, such as a photosensitive plate 1.
0E75 film or dry plate (manufactured by Agfa Agewald),
A 649F dry plate (manufactured by Eastman Kodak Co.) or the like is used.

The optical system for photographing has been described above, but in actual photographing, the entire optical system is used as a dark room, and the photosensitive plate 7 is placed at a predetermined position, and the red decomposition positive is placed at a predetermined position, and the mask 12 is placed at a predetermined position. Only the hole 13-R is left open, and the shutter 2 is opened for exposure for an appropriate time.

Next, replace the disassembly positive with a green disassembly positive, drill and expose only hole 13-G, then replace with a blue disassembled positive and hole 1
Only hole 3-B is opened to perform multiple recording of three colors on one photosensitive plate. The photosensitive plate thus subjected to multiple recording is subjected to appropriate processing such as reverse bleaching and development to obtain a multiple recorded image hologram.

Next, to describe image reproduction from the image hologram obtained as described above, as shown in FIG.
The white beam L-4 thus obtained is turned into parallel light by a lens 21, etc., and the incident angle θ of the beam for reference light is set at the hologram 2 from the opposite side.
Illuminate 2.

A projection lens 23 is arranged in front of the hologram, and a mask 24 is further arranged in front of the projection lens 23.

The projection lens 23 is preferably the same as the photographing lens 15.

The mask 24 has three holes 25-R, 25-G, 25-B.
This hole is located at the position described below.

That is, by illuminating the hologram 22 with a white beam L-4, the beam L-4 is diffracted by the hologram 22, and an image beam L is formed on the surface of the mask 24 with a certain band width for recording each color. -R, LG, LB are produced.

(See Figure 4) The image beam L-R is generated from the red recording, and similarly the image beams L-G and L-B are green and blue, respectively, and the band width depends on the chromatic dispersion of the hologram. This is what happened.

As shown in the figure, this band width has red → green → blue bands, respectively. A hole 25-R is made at the red band position of the red image beam LR, and a hole 25-R is made at the green band position of the red image beam LR. 25-G, and similarly drill a hole 25-B in the blue band of L-B.

Red, green, and blue color filters 26-R, 26-G, and 2 are placed in these holes 25-R, 25-G, and 25-B, respectively.
Install 6-B. A matte screen 27 for video is placed at a predetermined position in front of this mask, and images by beams LR, LG, and LB are connected to this matte screen, so that a color image is visible. The above has described a suitable example using a Leica-sized resolved positive film, but the position of the hole in the mask, the focal length of the lens, etc. are not limited to the above values, and the size of the resolved positive and the imaging magnification can be changed. It should be determined appropriately, taking into account the following. Since the present invention has the above-described configuration, it is possible to visualize images with clearness and good color compared to conventional methods, and it is also inexpensive in terms of equipment, does not require a laser light source for reproduction, and can be photographed and reproduced. It has extremely excellent practical effects, such as being easy and causing few troubles.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention; FIG. 1 is an explanatory diagram of a photographing optical system, FIG. 2 is a plan view of a mask for photographing, and FIG. 3 is an illustration of a reproduction optical system. FIG. 4 is a plan view of a reproduction mask. 1... light source, 2... shutter 3.
... Beam splitter 4 ... Mirror, 5 ... Magnifying lens, 6 ... Pinhole plate, 7 ... Photosensitive plate, 8 ... Magnifying lens, 9 ... Pinhole plate, 10 ... Diffusion plate, 11 ... Disassembled positive, 12 ... Mask, 13 ... hole, 14 ... light shielding plate,
15... Photographing lens, 20... White light source, 21... Lens, 22... Hologram, 23... Projection lens, 24...・・・・・・
Mask, 25...hole, 26...color filter 27...matte screen.

Claims (1)

[Claims] 1. A beam with high coherence is divided into two beams, one for reference light and one for signal light, and the reference light beam is illuminated on the photosensitive plate at an appropriate angle of incidence through a magnifying lens, and the signal light beam is One of the decomposition positives is illuminated through a magnifying lens, and the image of the decomposition positive is placed at an appropriate position on the surface of the photosensitive plate through any one hole of a mask with multiple holes and the photographing lens. An image is formed to record one color, and then the separated positives of other colors are exchanged and exposed through holes at other positions.After multiple recording and photographing of multiple colors is done in this way, the photosensitive plate A hologram is obtained by processing the hologram, and the hologram thus obtained is illuminated with the incident angle of the reference beam used for recording, and a projection lens provided in front of the hologram is used. At the same time, among the image beams emitted from this projection lens, the color band of each record is projected through a color filter of a color corresponding to the band width generated by the optical dispersion of each record. Featured color hologram shooting and playback method.