JP5534136B2 - hologram - Google Patents

Description

  The present invention relates to a hologram, and more particularly to a hologram that can be easily determined by visual inspection.

  At present, there are two types of holograms that are generally mass-produced. One is called a relief hologram or an embossed hologram, and this embossed hologram (relief hologram) is excellent in mass production, but it has been on the market for a while, and imitations of similar levels have been produced. I'm stuck.

  The other is a Lippmann hologram or a volume hologram. The Lippmann hologram has three-dimensional effects in the vertical and horizontal directions and has characteristics that are not available in embossed holograms, such as excellent wavelength selectivity, and it is very difficult to manufacture a counterfeit product.

  However, Lippmann holograms, which can only employ the optical replication method, are inferior in terms of mass productivity, and are expensive in terms of cost.

  Therefore, in the present invention, a new technique has been devised that achieves both the excellent mass productivity of embossed holograms and the difficulty of imitating Lippmann holograms.

  By the way, among relief holograms or embossed holograms, there are holograms such as rainbow holograms and computer generated holograms (CGH) that can reproduce white light and have parallax (three-dimensional effect) only in the horizontal direction. The rainbow hologram enables white light reproduction by removing vertical parallax from the reproduced image (Non-Patent Documents 1 to 3). In addition, the CGH having parallax only in the horizontal direction forms a large number of linear divided regions by dividing the original image formed of a stereoscopic image and the hologram recording surface in the horizontal direction by a large number of parallel cut surfaces. A divided area is set such that the divided area of the image and the divided area of the recording surface have a one-to-one correspondence, and a point or line segment light source array is arranged in each of a large number of divided areas of the original image. A large number of calculation points are defined on the divided area, and for each calculation point, a point of the corresponding divided area of the original image or an object beam emitted from a line light source array and a reference beam incident from a specific direction The intensity of the formed interference wave is calculated, and the interference fringes are recorded on the recording medium (Patent Documents 1 to 3). These CGHs eliminate vertical parallax by limiting the vertical spread angle of object light from each point or line segment light source.

Japanese Patent No. 3810917 Japanese Patent No. 3892619 JP 2001-109362 A

Shunichi Tanaka “Optical Application Machine Industry Technical Staff Training Text Optical Application Technology 1988 Version II-1 Optics (2) Wave Optics”, Japan Opto-Mechatronics Association, May 20, 1988, p. 92-93 Junpei Kajiuchi, “Physics Selection 22 Holography”, 1st edition, Hankabo Co., Ltd., November 5, 1997, p. 134-143 Toshihiro Kubota, "Introduction to Holography-Principles and Practices", first edition, second edition, Asakura Shoten Co., Ltd., March 1, 1997, p. 50-52 May 20, 1988, p. 92-93

  As described above, the conventional relief hologram or embossed hologram capable of reproducing white light can reproduce and observe a stereoscopic image with parallax in the horizontal direction, but reproduce and observe an image with parallax in the vertical direction. It is not possible.

  The present invention has been made in view of such problems of the prior art, and the object thereof is to provide parallax not only in the horizontal direction but also in the vertical direction in a relief hologram or an embossed hologram capable of reproducing white light. This is to make a stereoscopic image reproducible.

  The hologram of the present invention that achieves the above object has a plurality of parallaxes only in the horizontal direction to reproduce an image viewed from a different viewpoint in a vertical direction with respect to a specific three-dimensional object so that it can be viewed by an observer at the corresponding viewpoint position. This relief hologram is synthesized.

  In this case, the plurality of relief holograms are subdivided according to the same division pattern, the subdivision areas of the respective holograms are selected at a predetermined cycle, and the relative positions of the selected subdivision areas are fixed. The plurality of relief holograms may be synthesized by combining the hologram subdivision region and the hologram in parallel on one surface.

  In this case, it is desirable that the division interval in at least one direction of the division pattern is 300 μm or less.

  Alternatively, the plurality of relief holograms may be multiplexed and synthesized.

  In addition, it is desirable that an angle difference between different viewpoints in the vertical direction is 15 ° or less.

  The plurality of relief holograms may be rainbow holograms or computer generated holograms.

  In addition, it is desirable that a character symbol for distinguishing at least upper, lower, left and right is recorded on the side surface of the reproduced three-dimensional object image.

  In this case, the length of one side of the character symbol is desirably 300 μm or less.

  In the above, the shape of the three-dimensional object recorded in each hologram may be modified so that the parallax corresponding to the viewpoint in the vertical direction of the image reproduced from the plurality of relief holograms is enhanced.

  According to the present invention, for a specific three-dimensional object, a hologram having a three-dimensional effect not only in the horizontal direction but also in the vertical direction can be provided at a low cost with respect to a conventional Lippmann hologram.

It is a figure which shows the imaging arrangement | positioning of the H1 hologram of the 1st step at the time of producing the rainbow hologram of this invention by a 2 step method. It is a figure which shows the imaging | photography arrangement | positioning of the several 2nd step H2 hologram from which a viewpoint differs from the 1st step H1 hologram produced in FIG. It is a figure for demonstrating the observation image reproduced from the H2 hologram of the 2nd step produced in FIG. It is a figure which shows the example of the observation image of FIG. It is a figure for demonstrating an example of the method of synthesize | combining the H2 hologram of FIG. 3 to one hologram, and making it the hologram of this invention. It is a figure which shows the method of image | photographing a H2 hologram as a hologram of this invention directly. It is a figure for demonstrating a mode that the stereoscopic image which has a parallax not only in right and left but also in the upper and lower sides from the hologram obtained by the method of FIG. 6 can be observed. It is a figure corresponding to Drawing 1 for emphasizing the parallax of the perpendicular direction about the same solid object, and photographing. It is a figure corresponding to FIG. 2 in the case of the example of FIG. It is a figure which shows the method of image | photographing as a hologram of this invention directly instead of FIG. It is a figure for demonstrating the observation image reproduced from the H2 hologram of the 2nd step produced in FIG. 9, FIG. FIG. 9 is a diagram corresponding to FIG. 8 for photographing a plurality of H1 holograms using a deformed three-dimensional object.

  The hologram of the present invention will be described below based on examples.

  First, an example of a method for producing a hologram of the present invention will be described. In this manufacturing method, two rainbow holograms having different viewpoints with respect to the same three-dimensional object are prepared by a two-step method (two-step method), and the two rainbow holograms are combined by area division. This is a method for producing a hologram. The first-stage hologram (hereinafter referred to as H1 hologram) is a normal three-dimensional Fresnel hologram, and a recorded three-dimensional object image is reproduced from the recorded H1 hologram. In this method, two rainbow holograms having different viewpoints are prepared by sequentially arranging hologram recording materials for the second stage hologram in the vicinity of the reproduced object image.

  Hereinafter, description will be given with reference to the drawings. FIG. 1 is a diagram showing the imaging arrangement of the first stage H1 hologram when the rainbow hologram of the present invention is produced by this two-step method. First, as shown in FIG. 1, a three-dimensional object to be recorded (here, a truncated cone with the smaller top surface facing the recording side is assumed, using the photosensitive material 11 for H1 hologram recording at the first stage. .) The photosensitive material 11 is arranged facing O. Then, the three-dimensional object O of the photosensitive material 11 is illuminated with laser light of a predetermined wavelength so that the object light 12 scattered by the three-dimensional object O is incident on the photosensitive material 11 and the object is incident on the surface of the photosensitive material 11 at an incident angle θ. Reference light 13 consisting of parallel light from the same light source that is coherent with the light 12 is simultaneously incident, and the photosensitive material 11 is exposed to the hologram of the three-dimensional object O. The photosensitive material 11 exposed as described above is developed and the H1 hologram 11 is produced. Here, the photosensitive material 11 and the H1 hologram 11 are denoted by the same reference numeral 11.

Next, as shown in FIG. 2 (a), close to the incident side or exit side of the H1 hologram 11 (in the case of the figure, the incident side), and relatively horizontally in the figure (perpendicular to the plane of the figure). The first slit plate 22 ₁ provided with the first slit 23 ₁ extending in the direction) is disposed, and the first slit plate 22 ₁ is disposed via the first slit plate 22 ₁ (when the first slit plate 22 ₁ is disposed on the incident side) or directly (When the first slit plate 22 ₁ is arranged on the exit side) Reference light 13 at the time of recording on the H1 hologram 11
And the reproduction illumination light 24 traveling in the opposite, when the incident from the side opposite to the side where the reference light 13 when the recording with respect to H1 hologram 11 is incident, H1 through the hologram 11 at positions corresponding to the first slit 23 ₁ Diffracted light 25 ₁ is generated on the transmission side, and a three-dimensional image O ′ of the three-dimensional object O is reconstructed by the diffracted light 25 _{1 at} the position of the three-dimensional object O at the time of recording with respect to the surface of the H1 hologram 11. A second-stage H2 hologram recording photosensitive material 21 ₁ is disposed in the vicinity of the position where the stereoscopic image O ′ is formed, and diffracts the reference light 26 composed of parallel light from the same light source that can interfere with the reproduction illumination light 24. The first H2 hologram 21 ₁ is made to enter simultaneously from the same side as the light 25 _{1 at an} arbitrary incident angle φ, expose the first H2 hologram in the second stage in the photosensitive material 21 ₁ , and develop it. Is made. Here, the photosensitive material 21 ₁ and the first H2 hologram 21 ₁ are denoted by the same reference numeral 21 ₁ .

Then, as shown in FIG. 2 (b), H1 hologram 11 remains positioned in FIG. 2 (a), a second slit plate 22 ₂ position of the first slit plate 22 ₁ in the first place of the slit plate 22 ₁ To place. The second slit plate 22 ₂ is provided with a second slit 23 ₂ extending in parallel (horizontal direction) with the first slit 23 _{1 at} a relatively lower position in the drawing. Then, via the second slit plate 22 ₂ (when the second slit plate 22 ₂ is arranged on the incident side) or directly (when the second slit plate 22 ₂ is arranged on the exit side), When the reproduction illumination light 24 traveling in the direction opposite to the reference light 13 at the time of recording is incident on the H1 hologram 11 from the side opposite to the side on which the reference light 13 at the time of recording is incident, it corresponds to the second slit 23 ₂ . The diffracted light 25 ₂ is generated on the transmission side from the H1 hologram 11 at a position where the three-dimensional object O is to be transmitted. Reconstructed image is formed. A second H2 hologram recording photosensitive material 21 ₂ in the second stage is arranged in the vicinity of the position where the stereoscopic image O ′ is formed, and the reference light composed of parallel light from the same light source that is coherent with the reproduction illumination light 24. 26 is simultaneously incident from the same side as the diffracted light 25 ₂ at the same incident angle φ as in the case of FIG. 2A, and the second H2 hologram in the second stage is exposed in the photosensitive material 21 ₂ and developed. Thus, the second H2 hologram 21 ₂ is produced. Here, the photosensitive material 21 ₂ and the second H2 hologram 21 ₂ are denoted by the same reference numeral 21 ₂ .

The first H2 hologram 21 ₁ and the second H2 hologram 21 ₂ in the second stage thus produced are rainbow holograms, and as shown in FIGS. 3A and 3B, the H2 hologram 21 _{1 is used.} When the reproduction illumination light 31 traveling in the direction opposite to the reference light 26 at the time of 21 ₂ exposure is incident on the H2 holograms 21 ₁ and 21 ₂ from the side opposite to the side on which the reference light 26 at the time of recording is incident, Diffracted beams 33 ₁ and 33 ₂ are generated, and have the same size as the first slit 23 ₁ and the second slit 23 ₂ at the relative positions 32 ₁ and 32 ₂ corresponding to the first slit 23 ₁ and the second slit 23 ₂ , respectively. forming a pupil, by positioning the eye E to their pupil position, the stereoscopic image O 'of the three-dimensional object O image O ₁ "as viewed from the first slit 23 ₁ position, the second position of the slit 23 ₂ The seen image O ₂ ”is the H2 hologram 21 ₁ , 21 ₂ is reproduced near the position and can be observed. Since each of the first H2 hologram 21 ₁ and the second H2 hologram 21 ₂ is a rainbow hologram, parallax (three-dimensional effect) is not observed in the longitudinal direction of the first slit 23 ₁ and the second slit 23 ₂ , that is, in the horizontal direction. ), And examples of respective observation images are shown in FIGS.

FIG. 4A shows a case where the eye E is positioned at the relative position 32 ₁ of the first H2 hologram 21 _1, and the image O ₁ ″ seen when the eye E is moved from the left side to the center side and to the right side. In this example, the numbers “3”, “4”, “1”, and “2” are attached to the top, bottom, left, and right side surfaces of the truncated cone of the three-dimensional object O to be recorded as a hologram, respectively. When the eye E is viewed at the relative position 32 ₁ of the first H2 hologram 21 ₁ , an image O ₁ ″ that looks down on the three-dimensional object O from above can be seen. When positioning the eye E to the left of the relative positions 32 _1, see the "1" on the left side and "3" on the truncated cone side surface and is positioned in the center of the relative position 32 _1, the upper side mainly "3 "it is visible, and the left and right sides" 1 "and" 2 "is partially visible, when is located on the right side of the relative position 32 _1, the upper surface""on the right side and" 3 2 "is visible.

FIG. 4B shows a case where the eye E is positioned at the relative position 32 ₂ of the second H2 hologram 21 _2, and the image O ₂ ″ seen when the eye E is moved from the left side to the center side and to the right side. When the eye E is positioned at the relative position 32 ₂ of the second H2 hologram 21 ₂ , an image O ₂ ″ that looks up at the three-dimensional object O from below is seen. When the eye E is positioned on the left side of the relative position 32 ₂ , the lower side “4” and the left side “1” are visible, and when the eye E is positioned at the center of the relative position 32 ₂ , the lower side “4” is mainly visible. and, "1" and "2" of the right and left sides partially visible, when is located on the right side of the relative position 32 _2, visible "2" on the right side and "4" of the lower surface.

The object of the present invention is to synthesize a plurality of rainbow holograms with different vertical positions of the viewpoint with respect to such a three-dimensional object O. In the above example, two rainbow holograms are combined into one hologram, and the viewpoint with respect to the rainbow holograms is moved up and down. It is to make an image with parallax visible in the vertical direction when moved. An example of the synthesis method will be described with reference to FIG. 5. The first H2 hologram 21 ₁ and the second H2 hologram 21 ₂ are subdivided according to the same division pattern. In the example of FIG. 5, it is equally divided in the vertical direction into strip-like subdivision areas elongated in the horizontal direction. In the case of the first H2 hologram 21 ₁ , the subdivision areas are A1, A2, A3, A4, A5, A6, A7, A8 from top to bottom, and in the case of the second H2 hologram 21 ₂ , B1, B2, B3 , B4, B5, B6, B7, B8. In the first H2 hologram 21 ₁ , odd-numbered ones A1, A3, A5, and A7 are selected as the subdivision areas, and the areas A2, A4, A6, and A8 are blanked while the relative positions are fixed. In the second H2 hologram 21 ₂ , even-numbered ones B2, B4, B6, and B8 are selected and fitted in the blank position of the _first H2 hologram 21 ₁ with the relative positions fixed. Thus, the composite hologram 1 according to the present invention is obtained by arranging the subdivided regions side by side with A1, B2, A3, B4, A5, B6, A7, and B8 and integrating them.

When positions the eye to the relative position 32 ₁ relative to the composite hologram 1 (relative position 32 ₁ relative to the first H2 hologram 21 ₁ portion of the composite hologram 1), the left and right as shown in FIG. 4 (a) parallax there visible image O ₁ "as overlooking the stereoscopic object O from above. also, the relative positions 32 ₂ to the composite hologram 1 (relative position 32 ₂ for the second H2 hologram 21 ₂ parts of the composite hologram 1) When the eye is positioned on the left side, an image O ₂ ″ with a parallax on the right and left as shown in FIG. Therefore, when the composite hologram 1 is observed with both eyes, not only there is a parallax on the left and right, but also a stereoscopic image with a parallax on the top and bottom and a stereoscopic effect can be observed.

By the way, the same division pattern of the first H2 hologram 21 ₁ and the second H2 hologram 21 ₂ is not limited to the division pattern vertically divided into strip-like subdivision areas elongated in the horizontal direction as described above. However, in order to increase the resolution in the left-right direction (horizontal direction), which is the main parallax direction, it is desirable to divide into strips that are elongated in the horizontal direction. In addition, the division interval of the division pattern is desirably 300 μm or less, preferably 100 μm or less because it is desirable that the division pattern cannot be decomposed by human eyes.

  Further, as described in the example of FIG. 4, when a hologram is recorded with a fine character symbol C attached to the upper, lower, left and right side surfaces of the three-dimensional object O to be recorded as a hologram, the character symbol C on the side surface is discriminated. Thus, it can be determined whether or not the hologram 1 is genuine. In that case, it is desirable that the length of one side of the character size of the character symbol C attached to the side surface is 300 μm or less.

By the way, in the above example, a rainbow hologram as shown in FIGS. 3A and 3B is assumed as a hologram that has a parallax only in the horizontal direction and can arbitrarily set the viewpoint in the vertical direction. As a hologram that has a parallax only in the horizontal direction and can arbitrarily set the viewpoint in the vertical direction, there is a computer generated hologram (CGH) as described in Patent Documents 1 to 3, for example. In the case of CGH, the CGH having the same characteristics as those in FIG. 3 is calculated by defining the three-dimensional object O in the computer without taking the photographing method as shown in FIGS. 1 and 2 using the actual three-dimensional object O. Can be produced. When the composite hologram 1 using such CGH as a hologram 21 _1, 21 _2, both the hologram 21 _1, 21 ₂ of the synthesis process according to such area division shown in FIG. 5 is suitable.

By the way, there is a method of simultaneous multiplex recording as another embodiment for forming a hologram having not only right and left parallax but also vertical parallax in a rainbow hologram. An example of this will be described with reference to FIG. This figure is a diagram illustrating a method of photographing H2 hologram used in place of 2, a first slit 23 ₁ extending in the horizontal direction provided in the first slit 23 ₁ position of the first slit plate 22 ₁ in FIG. 2 , provided in the second slit plate 22 of the _second second slits 23 ₂ and parallel to each other one of the slit plate 22 extending in the horizontal direction provided at a position of the slit 23 _2, the method of this slit plate 22 in FIG. 1 The first-stage H1 hologram 11 produced in step 1 is disposed close to the incident side or the exit side (incident side in the case of the figure), and the slit plate 22 is interposed (when the slit plate 22 is disposed on the incident side). Or directly (when the slit plate 22 is arranged on the exit side), the reproduction illumination light 24 traveling opposite to the reference light 13 at the time of recording is applied to the H1 hologram 11 as a reference light at the time of recording with respect to the H1 hologram 11. 13 is incident That when the side is incident from the opposite side, diffracted light 25 ₁ H1 through the hologram 11 at positions corresponding to the first slit 23 _1, diffracted light 25 ₂ H1 through the hologram 11 in the position corresponding to ₂ second slit 23 A three-dimensional image O ′ of the three-dimensional object O is reproduced and imaged by these diffracted beams 25 ₁ and 25 _{2 at} the position of the three-dimensional object O generated on the transmission side and recorded on the surface of the H1 hologram 11. The second-stage H2 hologram recording photosensitive material 21 is disposed in the vicinity of the position where the stereoscopic image O ′ is formed, and the reference light 26 composed of parallel light from the same light source that is coherent with the reproduction illumination light 24 is diffracted light. The H2 hologram 21 is produced by making it incident simultaneously with an arbitrary incident angle φ from the same side as 25 ₁ and 25 ₂ , exposing the second stage H2 hologram in the photosensitive material 21, and developing it. Here, the photosensitive material 21 and the H2 hologram 21 are denoted by the same reference numeral 21.

The second stage H2 hologram 21 produced in this way is a multiple recording rainbow hologram. As shown in FIG. 7, the reproduction illumination light 31 traveling in the opposite direction to the reference light 26 at the time of exposure of the H2 hologram 21 is converted into an H2 hologram. 21 is incident from the side opposite to the side on which the reference light 26 is incident during recording, the first slits at relative positions 32 ₁ and 32 ₂ corresponding to the first slit 23 ₁ and the second slit 23 ₂ , respectively. 23 ₁ , pupils having the same size as the second slit 23 ₂ are formed, and the eye E is positioned at these pupil positions, so that the stereoscopic image O ′ of the stereoscopic object O is viewed from the position of the first slit 23 ₁ . The image O ₁ ″ (FIG. 4A) and the image O ₂ ″ (FIG. 4B) viewed from the position of the second slit 23 ₂ are spatially overlapped to form an image O ″ near the position of the H2 hologram 21. Therefore, H2 holo Ram 21, like the composite hologram 1, when the positions the eye E in the relative position 32 _1, the image O look down the right and left stereoscopic object O has parallax from above as shown in FIG. 4 (a) ₁ ”is visible. When the position of the eye E is moved in the vertical direction to position the eye E in the relative position 32 ₂ therefrom, such as looking up a three-dimensional object O has parallax in the left and right as shown in FIG. 4 (b) from below The image O ₂ ″ is visible. For this reason, when the H2 hologram 21 is observed with both eyes, not only there is a parallax on the left and right, but a stereoscopic image with a parallax on the top and bottom and a stereoscopic effect can be observed.

By the way, in the case of FIG. 2, FIG. 6, or when the H2 holograms 21 ₁ and 21 ₂ are formed by CGH, the angle difference between the first slit 23 ₁ and the second slit 23 ₂ with respect to the stereoscopic image O ′ is at most. It needs to be 15 °. If this angle difference is 15 ° or less, a three-dimensional object recorded from a different angle or a three-dimensional image observed at a different angle can be recognized as the same three-dimensional object. When this angle difference exceeds 15 °, it looks as if the three-dimensional object recorded from a different angle is switched, and it is difficult to obtain a desired effect (three-dimensional effect in the vertical direction).

In order to further enhance the vertical stereoscopic effect even if the angle difference between the first slit 23 ₁ and the second slit 23 ₂ with respect to the stereoscopic image O ′ is small, a plurality of images O ₁ ”reproduced by the holograms 1 and 21”. , O ₂ ″ is not an image with different viewpoints of the three-dimensional object O having the same spatial form as shown in FIG. 3, but a stereoscopic effect in the vertical direction can be more easily obtained by making the image with parallax enhanced. An example of this will be described below.

FIG. 8 is a diagram showing a shooting arrangement of the H1 hologram corresponding to FIG. In this case, the same number of H1 holograms as the plurality of images O ₁ ″ and O ₂ ″ are photographed. As shown in FIG. 8A, a three-dimensional object (here, a truncated cone with the smaller top surface facing the recording side is assumed) O slightly to the right around the normal of the surface of the figure. So that the upper side surface of the three-dimensional object O faces the surface of the first H1 hologram recording photosensitive material 11 ₁ disposed in front of the three-dimensional object O, and the three-dimensional object O of the photosensitive material 11 ₁ is irradiated with laser light having a predetermined wavelength. the illuminated object light 12 ₁ scattered by the three-dimensional object O and causes incident on the photosensitive material 11 _1, and the object beam 12 ₁ at an incident angle θ on the surface of the photosensitive material 11 ₁ from the parallel light from coherent same source the reference beam 13 formed by simultaneously incident to expose the hologram of a three-dimensional object O angular arrangement as the above photosensitive material 11 _1. The photosensitive material 11 ₁ is developed and the first H1 hologram 11 ₁ is produced. Further, as shown in FIG. 8B, a second H1 hologram in which the same three-dimensional object O is slightly tilted to the left around the normal line of the drawing and the lower side surface of the three-dimensional object O is disposed in front of the second H1 hologram. We should face the recording photosensitive material 11 _{and second} surface, scattered by solid object O to illuminate the three-dimensional object O of the photosensitive material 11 ₂ in the laser beam having the same wavelength as that of the first H1 hologram 11 ₁ object with light enters 12 ₂ to the photosensitive material 11 _2, at the same time by a reference light 13 consisting of parallel light from the object light 12 ₂ coherent same light source at an incident angle θ on the surface of the photosensitive material 11 _2, the light-sensitive material 11 ₂ for exposing the hologram of a three-dimensional object O angular arrangement as described above. The photosensitive material 11 ₂ is developed and the second H1 hologram 11 ₂ is produced. Here, the photosensitive materials 11 ₁ and 11 ₂ and the H1 holograms 11 ₁ and 11 ₂ are denoted by the same reference numerals 11 ₁ and 11 ₂ .

Next, as shown in FIG. 9A, the first slit plate 22 ₁ shown in FIG. 2A is placed close to the incident side or the exit side of the first H1 hologram 11 ₁ (in the case of FIG. 9A). The first slit plate 22 ₁ similar to the above is arranged, and the reproduction illumination light 24 that travels through the first slit plate 22 ₁ or directly goes to the first H1 hologram 11 ₁ opposite to the reference light 13 at the time of recording. the, if the side where the reference light 13 when the recording on the first H1 hologram 11 ₁ is incident to the incident from the opposite side from the first H1 hologram 11 ₁ at the position corresponding to the first slit 23 ₁ Diffracted light 25 ₁ is generated on the transmission side, and the three-dimensional image O ₁ ′ of the three-dimensional object O is reproduced by the diffracted light 25 _{1 at} the position of the three-dimensional object O at the time of recording with respect to the surface of the first H1 hologram 11 _1. Imaged. A second-stage H2 hologram recording photosensitive material 21 is arranged in the vicinity of the position where the stereoscopic image O ₁ ′ is formed, and diffracts the reference light 26 composed of parallel light from the same light source that can interfere with the reproduction illumination light 24. At the same time from the same side as the light 25 ₁ and incident at an arbitrary incident angle φ, the first H2 hologram in the second stage is exposed in the photosensitive material 21.

Next, as shown in FIG. 9B, the second H1 hologram 11 ₂ is used instead of the position of the _first H1 hologram 11 ₁ , and the second slit shown in FIG. 2B is used instead of the first slit plate 22 ₁ . placing the plate 22 ₂ and the same second slit plate 22 ₂ to the first position of the slit plate 22 _1. 9A, when the reproduction illumination light 24 and the reference light 26 are incident, the diffracted light 25 ₂ is transmitted from the second H1 hologram 11 _{2 at} the position corresponding to the second slit 23 _2. The three-dimensional image O ₂ ′ of the three-dimensional object O is reproduced and imaged by the diffracted light 25 _{2 at} the position of the three-dimensional object O at the time of recording with respect to the surface of the second H1 hologram 11 _2. Two holograms for reproducing the stereoscopic image O ₁ ′ and the stereoscopic image O ₂ ′ are subjected to multiple exposure in the photosensitive material 21. The H2 hologram 21 is produced by developing the second stage H2 hologram recording photosensitive material 21 or the like. Here, the photosensitive material 21 and the H2 hologram 21 are denoted by the same reference numeral 21.

Instead of performing multiple exposure of the holograms of the stereoscopic image O ₁ ′ and the stereoscopic image O ₂ ′ by shifting the separate exposures in FIG. 9 in time, as shown in FIG. 10, the upper half of the _first H1 hologram 11 ₁ The lower half of the second H1 hologram 11 ₂ is connected to form a single H1 hologram 11 _3, and close to the incident or exit side of the H1 hologram 11 ₃ , the slit plate 22 similar to the slit plate 22 of FIG. Through the slit plate 22 (when the slit plate 22 is arranged on the incident side) or directly (when the slit plate 22 is arranged on the exit side) on the H1 hologram 11 ₃ at the time of each recording When the reproduction illumination light 24 traveling in the direction opposite to the reference light 13 is incident on the H1 hologram 11 ₃ from the side opposite to the side on which the reference light 13 is incident at the time of recording, the reproduction illumination light 24 is positioned at a position corresponding to the first slit 23 _1. H1 Hologram Diffracted light 25 ₁ from beam ₁₁₁ is diffracted light 25 ₂ is generated in each transmission side H1 through the hologram 11 ₂ at a position corresponding to the ₂ second slit 23, the three-dimensional when the recording with respect to the plane of the H1 hologram 11 The three-dimensional images O ₁ ′ and O ₂ ′ of the three-dimensional object O are spatially superimposed on the position of the object O and reconstructed by the diffracted light 25 ₁ . A second-stage H2 hologram recording photosensitive material 21 is arranged in the vicinity of the position where these three-dimensional images O ₁ ′ and O ₂ ′ are formed, and a reference comprising parallel light from the same light source that is coherent with reproduction illumination light 24. The light 26 is simultaneously incident at an arbitrary incident angle φ from the same side as the diffracted light 25 ₁ , 25 ₂ , the H2 hologram in the second stage is exposed in the photosensitive material 21, developed, etc. Make it. Here, the photosensitive material 21 and the H2 hologram 21 are denoted by the same reference numeral 21.

The second-stage H2 hologram 21 produced in this way is a multiple recording rainbow hologram as in FIG. 6, and is opposite to the reference beam 26 at the time of H2 hologram 21 exposure, as shown in FIG. When the reproducing illumination light 31 that travels is incident on the H2 hologram 21 from the side opposite to the side on which the reference light 26 is incident upon recording, the relative positions corresponding to the first slit 23 ₁ and the second slit 23 ₂ , respectively. 32 _1, 32 ₂ to the first slit 23 _1, to form a pupil of the second slits 23 ₂ in the same size, by positioning the eye E to their pupil position, the relative position 32 _1, the three-dimensional object O O ₁ ″ recorded with emphasis on parallax so that the upper side surface can be observed more is recorded with emphasis on parallax so that the lower side surface of the three-dimensional object O is more observed at the relative position 32 ₂ . O ₂ ” Born. Therefore, when the eye E is positioned at the relative position 32 ₁ , the H2 hologram 21 is O ₁ ″ with parallax on the left and right as shown in FIG. 4A and looking down on the three-dimensional object O from above. vertical parallax appear to be more emphasized. when the position of the eye E is moved in the vertical direction to position the relative position 32 ₂ to the eye E therefrom parallax to the right and left as shown in FIG. 4 (b) It is O ₂ ″ that looks up at a certain three-dimensional object O from below, and the upper and lower parallax appear to be more emphasized. Therefore, when the H2 hologram 21 is observed with both eyes, there is not only a parallax on the left and right, but also a parallax emphasized on the top and bottom, and a stereoscopic image with a stereoscopic effect can be observed.

In the case of FIG. 8, in order to emphasize the stereoscopic effect in the vertical direction, the same three-dimensional object O is tilted at different tilt positions when shooting a plurality of H1 holograms having different vertical viewpoints. Then, it becomes difficult to observe, for example, the top surfaces of the images O ₁ ″ and O ₂ ″ of the three-dimensional object O (especially when having a top surface like a truncated cone) are not in focus, or they do not look natural. Problems may arise. Therefore, instead of 8, as shown in FIG. 12, each of the H1 hologram recording photosensitive material 11 _1, 11 ₂ to separate solid objects O _1, O H1 hologram 11 ₁ of _2, 11 ₂ to shoot It may be. These three-dimensional objects O ₁ and O ₂ have the same top surface, and the back forms of the three-dimensional objects O ₁ and O ₂ are respectively deformed upward and parallel O ₁ , and deformed downward and parallel O ₂ . When the hologram of the present invention is configured by CGH, the three-dimensional object defined for recording in the holograms 21 ₁ and 21 ₂ is deformed and recorded respectively.

In the above description, whether the hologram of the present invention is composed of a rainbow hologram or a CGH, two holograms having different viewpoints in the vertical direction are combined. Of course, it may be 3 or more. However, as the number of viewpoints increases, noise due to chromatic dispersion in the vertical direction increases in the observation image at each viewpoint. Therefore, if the hologram is to be observed under white light, use two or three different viewpoints. In the case of a hologram to be observed under monochromatic light, a larger number of viewpoints may be used.

  The hologram of the present invention consisting of a rainbow hologram or CGH is generally configured as a relief hologram, but in order to produce the relief hologram, a mold having the relief pattern formed on a synthetic resin or the like is used. An embossed hologram is produced by embossing and shaping. In the case of CGH, an original plate is produced by the EB drawing method, the concave / convex relief pattern is provided on the mold, and the mold is formed to produce CGH as an embossed hologram. The hologram of the present invention can be configured as a reflective embossed hologram by providing a reflective layer such as metal plating on the relief surface of the embossed hologram or on the opposite surface.

  Although the hologram of the present invention has been described based on the embodiments, the present invention is not limited to these embodiments and can be variously modified.

  According to the present invention, for a specific three-dimensional object, a hologram having a three-dimensional effect not only in the horizontal direction but also in the vertical direction can be provided at a low cost with respect to a conventional Lippmann hologram.

E ... viewed from the eye O ... stereoscopic object O _1, O ₂ ... stereoscopic object O '... image and position of the second slit as viewed a stereoscopic image of a stereoscopic image O "... stereoscopic object of the stereoscopic object from the position of the first slit The images O ₁ ″ are spatially overlapped and the image O ₂ ″ is a stereoscopic image of the three-dimensional object viewed from the position of the first slit. The image C is a three-dimensional image of the three-dimensional object viewed from the position of the second slit. DESCRIPTION OF SYMBOLS 1 ... Composite hologram 11 ... Photosensitive material for H1 hologram recording (H1 hologram)
11 ₁ ... First H1 hologram recording photosensitive material (first H1 hologram)
11 ₂ ... Second H1 hologram recording photosensitive material (second H1 hologram)
11 ₃ ... H1 hologram 12 formed by connecting the first H1 hologram and the second H1 hologram 12. Object light 12 ₁ , 12 ₂ ... Object light 13... Reference light 21... H2 hologram recording photosensitive material (H2 hologram)
21 ₁ ... First H2 hologram recording photosensitive material (first H2 hologram)
21 ₂ ... Second photosensitive material for recording H2 hologram (second H2 hologram)
22 ... slit plate 22 ₁ ... first slit plate 22 ₂ ... second slit plate 23 ₁ ... first slit 23 ₂ ... second slit 24 ... reproduction illumination light 25 _1, 25 ₂ ... diffracted light 26 ... reference light 31 ... reproduction Illumination light 32 ₁ ... Pupil position 32 ₂ corresponding to the first slit 32. Pupil positions 33 ₁ and 33 ₂ corresponding to the second slit

Claims (8)

Multiple relief holograms that have parallax only in the horizontal direction are reproduced according to the same division pattern, so that images viewed from different vertical viewpoints can be viewed by a viewer at a corresponding viewpoint position. By selecting a subdivision area of each hologram at a predetermined period and combining the selected subdivision areas of the plurality of relief holograms in parallel on the same plane with subdivision areas of other holograms. A hologram characterized by being synthesized. Hologram according to claim 1, wherein the at least one direction of the divided intervals of the divided pattern is characterized in that at 300μm or less. 3. The hologram according to claim 1, wherein an angle difference between different viewpoints in the vertical direction is 15 ° or less. Any one hologram according to claim 1 to 3, wherein the plurality of relief hologram is characterized by comprising the rainbow hologram. Any one hologram of claims 1 to 3, wherein the plurality of relief hologram is made of a computer generated hologram. The hologram according to any one of claims 1 to 5 , wherein a character symbol for distinguishing at least upper, lower, left and right is recorded on a side surface of a three-dimensional object image to be reproduced. The hologram according to claim 6, wherein a length of one side of the character symbol is 300 μm or less. The shape of the three-dimensional object recorded on each hologram is deformed so that the parallax corresponding to the viewpoint in the vertical direction of the image reproduced from the plurality of relief holograms is enhanced. The hologram according to any one of 7 .

Images