JP3007360B2 - Multiple hologram element and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention includes a multiplexed hologram element in which a plurality of holograms are recorded in the same element and read out and used as appropriate, and a technique for mass-producing the element. It concerns the duplication method.

(Prior Art) When the intensity and phase are recorded on a photographic dry plate or the like capable of optically recording scattered light from an object and a reproduced image is desired to be obtained, the photographic dry plate or the like is irradiated with a plane wave of light such as a laser beam from the object. A technique for reproducing the scattered light from the hologram is called holography, and a collection of interference fringes having intensity and phase recorded on a photographic plate or the like is collectively called a hologram.

Holograms have already been used in various applications and decorations as a Lippmann-type hologram reproducible with white light, a credit card mark or a film or seal showing a three-dimensional image as integral photography.

FIG. 2 is a diagram showing the concept of conventional hologram recording, in which 21 is coherent light, 22 is reference light, 23 is object light, 24
Denotes a recording medium, 25 denotes an object, and 26 denotes a half mirror. x, y,
z indicates a coordinate axis, O indicates an origin, and θr indicates a light intersection angle. On the recording medium 24, interference fringes of the reference light 22 and the object light 23 are recorded.

FIG. 3 is a diagram showing the concept of conventional hologram reproduction, in which 31 is a reproduction light, 32 is a recording medium on which interference fringes are recorded, 33 is a virtual image by hologram reproduction, and 34 is a phase conjugate image. As shown in FIG. 3, a virtual image 33 and a conjugate image 34 of the object 25 are reproduced by the reproduction light 31. On the recording medium 32, complicated interference fringes are drawn over a wide surface as shown in the figure.

The multiplex hologram records a plurality of holograms described above on one recording medium surface, and FIG. 4 shows the concept of a conventional multiplex hologram recording example. FIG. 4 shows both the object light 41 and the reference light 42 as plane waves in order to form a simple model. 43 indicates a recording medium, and 44 indicates a recorded interference fringe. The arrow indicates the direction in which the recording medium 43 is rotated.

For example, if the object light 41 and the reference light 42 are plane waves as shown in FIG. 4, the interference fringes 44 are linear and are arranged at regular intervals in a certain direction. When the recording medium 43 is rotated, straight lines at equal intervals are arranged at an angle different from the original direction.

FIG. 5 is a conceptual diagram of a conventional example of reproducing a multiplexed hologram, in which 51 is a first reproduced light from a first angle, 52 is a first reproduced image by a first hologram 53 (solid line), and 54 is a first reproduced image. The second reproduction light 55 from the second angle, the second reproduction light 55 from the second reproduction light 54
2 shows a second reproduced image of the hologram 56 (a dashed line).

As can be seen from FIGS. 4 and 5, this conventional multiplexed hologram composed of two holograms is constructed as a superposition of straight lines having different angles on the same plane. As in the example shown in FIG. 5, when the interference fringes to be recorded are plane waves, the interference fringes are only straight lines having a fixed angle. Therefore, when reproducing a multiplexed hologram, the first and second holograms 5 are used.
3,56 interference fringes (act as noise on each other's signal)
Is relatively small.

However, as shown in FIG. 3, the interference fringes of a complex object, as shown in FIG. 3, are composed of various curves over the entire surface of the recording medium. There is a drawback that it is difficult to distinguish the original interference fringes from each other, the component acting as noise increases, and a sufficient resolution of a reproduced image cannot be obtained.

Two methods are conceivable as conventional means for solving this. One method is to increase the area of the recording medium and shift the center of the hologram, as shown in FIG.

In FIG. 6, reference numeral 68 denotes a recording medium, 61 and 64 denote different object beams, and 62 and 65 denote reference beams respectively corresponding to the object beams 61 and 64. 68 and 66 indicate hologram areas corresponding to (61, 62) and (64, 65), respectively. Reference numeral 67 denotes an overlapping portion between the two hologram regions.

In this method, since there are few overlapping portions, the reproduced image is better than that in FIG. 5, but the area of the recording medium becomes larger,
Reproduction has a drawback that the reference light, the object light, and the position of the recording medium need to be moved.

Another proposed means is a stereo multiplexed hologram, which is a method of recording interference fringes to be recorded in a volume space of a recording medium as shown in FIG.

7, reference numeral 71 denotes a volume hologram recording medium, 72 denotes a first object beam, 73 denotes a first reference beam, 74 denotes a first volume hologram region by (72, 73), and 75 denotes a second object beam. , 76 indicate the second volume hologram area according to (73,75). As shown in FIG. 7, the volume hologram recording areas indicated by 74 and 76 are spatially (volumely) widened, so that the reproduction efficiency is extremely high. For this reason, a small volume hologram recording area overlaps. However, compared to the example of flat recording illustrated in FIG. 4, the influence of noise of the reproduced image on other recordings is small.

As described above, the volume hologram has excellent characteristics as a multiplex hologram element, but since the interference fringes are distributed in the spatial direction, mass production cannot be performed by a stamper, a press, or the like. Had become.

As a method for solving this, the element structure shown in FIG. 8 can be considered. In FIG. 8, reference numeral 81 denotes a hologram recording medium surface developed in multiple layers, 82 denotes reference light, 83 and 84 denote object lights, 85, 86, 87 and 88.
Indicates the interference fringe recording surface.

This method is theoretically simple because the volume hologram is replaced with a stack of recording media.However, in practice, it is very difficult to make a replica on a plane and return to the original position interval, and the disadvantage of the conventional multiple hologram element is eliminated. It is hard to say that it was resolved.

(Problems to be Solved by the Invention) The present invention has been made in view of the above-mentioned conventional disadvantages,
It is an object of the present invention to provide a multiplexed hologram element in which a plurality of holograms are recorded in the same element, and are read out and used as appropriate, and a method of manufacturing the same.

(Means for Solving the Problems) A multi-hologram element according to the present invention is a multi-hologram element for recording a plurality of interference fringes formed by interference of two light beams in the same element. A hologram is formed by a total reflection mirror having a shape, and a multiple hologram is formed on an inner surface thereof.

FIG. 1 shows an example of the configuration of the multiple hologram element of the present invention.

The multiple hologram element 11 shown in FIG. 1 is constituted by a total reflection type mirror, and has a hollow cylindrical shape having a hologram recording medium provided on an inner surface thereof. 12 is a reference light, 13 and 14 are object lights from different directions, and 15 is a reference light 12
16 is an interference fringe recording area only by the reference light 12 and the object light 14, 16 is an interference fringe recording area only by the reference light 12 and the object light 13, and 17 is an interference fringe recording area by the object light 13 and the reference light 12 reflected by the mirror.
5 shows an interference fringe recording area in which interference fringes due to the reference light 12 are recorded in an overlapping manner.

As is clear from FIG. 1, although there is a portion 17 where the interference fringe recording areas overlap with the two object beams 13 and 14, it is easily understood that each interference fringe is recorded separately.

FIG. 9 shows a part of the object light in the multiple hologram element shown in FIG. 1 traced from the upper surface of the element by a geometrical trajectory, where 91 is the multiple hologram element and 92 is a part of the incident light which is the object light. Is shown.

As is clear from FIG. 9, the incident light beam 92 travels from the upper surface to the lower surface of the cylinder while turning the inner surface of the multiple hologram element 91 back. Here, when it is considered that interference fringes corresponding to each of the reflection surfaces are generated, it can be easily understood that light is evenly reflected on the side surface of the cylinder, and the interference fringes are recorded accordingly.

FIG. 10 is a diagram showing another configuration example of the multiple hologram element of the present invention, where 10 is a multiple hologram element having a square hollow quadrangular prism section formed by a total reflection mirror, 12 is a reference beam, and 13 is The first object light 14 is a second object light. No.
FIG. 10 (b) shows a state in which the hollow cylindrical multiple hologram element shown in FIG. 10 (a) is developed on a plane, where 18 is the developed medium surface, and 15 and 16 are the object light 13 and 14, respectively. The corresponding interference fringe area is shown.

In this multiplex hologram configuration, it can be schematically understood that the hologram recording surface can be used with a wide area and little overlap.

In this embodiment, the case where holograms are recorded on both side surfaces of the hollow rectangular prism shown in FIG.
The same applies to multiplexing using upper and lower surfaces.

FIG. 11 shows a replica production process for producing a plurality of multiplex hologram elements of the present invention.

In FIG. 11, reference numeral 111 denotes a multiplexed hologram element, 112 denotes a multiplexed hologram element surface obtained by developing the multiplexed hologram element 111 on a plane, and 113 denotes a process shown in the figure (development, Ni vapor deposition or sputtering, master production by plating, master production of a stamper). And 116 is a multi-hologram element obtained by three-dimensionally restoring the flat replica 113. Reference numeral 114 denotes a concavo-convex inversion pattern, and reference numeral 115 denotes a multiplexed hologram transfer medium. By pressing the transfer medium 115 on the concavo-convex inversion pattern 114 by pressing, a multiplexed hologram element by a three-dimensional replica can be obtained.

As shown in FIG. 11, it can be understood that replicas can be easily duplicated by mass production using a conventional printing surface press and a roll press.

(Examples) The following examples of the present invention will be described in detail.

Example 1 A 35 mm × 31.4 mm polyethylene terephthalate (PET) film (film base for photography) having a thickness of 100 μm was brought into close contact with a quartz substrate, and Al was vapor-deposited on the quartz substrate by 2000 mm.
On top of that, 30 pieces of photoresist (OFPR-8000 manufactured by Tokyo Ohka) are added.
00Å Spin coated. Next, this film has an inner diameter of 10 mm.
Insert into the glass tube of φ
After being fixed so that the PET surfaces were in close contact with each other, prebaking was performed at 90 ° C. for 30 minutes to obtain a multiplex hologram element. Next, this glass tube was fixed to a holder, and an Ar laser beam (wavelength: 451 nm) having a diameter of 10 mm was used as a reference beam from the top surface of the tube, and the same Ar beam was formed from the side of the tube so as to form a 60 ° crossing angle with the reference beam. Laser light was sequentially irradiated at 60 ° intervals to the center of the upper surface of the tube as object light, and six multiplexed holograms were recorded in the multiplexed hologram element.

Next, the multiplexed hologram element was taken out of the glass tube, the resist in which the multiplexed hologram was recorded was developed, and post-baking was performed at 100 ° C. for 1 hour to record and fix irregularities corresponding to the hologram on the register surface. The multi-hologram element thus processed is returned to the glass tube again,
The tube was tightly fixed so that the PET surface was in contact with the inner surface of the tube. When this was irradiated with reference light, six virtual image images could be reproduced at the original object light positions.

The reproduction efficiency with respect to the reference light irradiated to the multiplex hologram element was 5%, which was higher than the reproduction efficiency of 1% when the multiplexed hologram element was multiplexed onto a plane of 10 mm square by 6%, and the image clarity was excellent.

The multiplexed hologram element was further taken out of the glass tube and developed to form a planar shape, and then Ni was vacuum-deposited on the surface of the recording medium to form a 500-nm thick Ni film. This Ni film surface has N
A 100 μm Ni stamper was prepared by performing electrolytic plating of i.

Using the Ni stamper manufactured in this way, multiple holograms are transferred to the vinyl chloride (thermoplastic resin) film surface by hot pressing to make a duplicate, and Al is deposited on the back surface of the concave and convex surface of the duplicate (800 °). After that, the duplicate is inserted into a glass tube and fixed so that the Al surface is in close contact with the inner surface of the tube, and when irradiated with reproduction light, six virtual image images can be reproduced at an efficiency of 3%. Thing was obtained.

Example 2 A multiplexed hologram master prepared in the same manner as in Example 1 was subjected to hologram recording and development in a cylindrical state, developed, and then coated with a dye absorbing the wavelength of the reproduction light laser to form an offset plate (intaglio printing). did.

This offset printing plate is pressed on the outer surface of an acrylic (PMMA) cylinder with a diameter of 10 mm and a length of 35 mm (side surface is optical grade flat finish), printing an absorbing dye pattern, drying and solidifying the dye. Evaporation was performed to obtain a hollow cylindrical multiple hologram duplicate.

This copy was an absorption multiplex hologram, and the reproduction efficiency of each image was 0.2%.

Example 3 In the same manner as in Example 1, a multiplexed hologram was prepared as a cylindrical surface, developed, post-baked, and then Ni was vapor-deposited at 1000 ° to prepare a duplication master.

Polyvinyl carbazole to the duplication master (M _W =
A mixture of 570,000) and camphorquinone thioflavin-T as a sensitizer was applied to the uneven surface of the master to form an intaglio ink. This was pressed on the outer surface of the acrylic cylinder, and the solution was infiltrated into the PMMA cylinder, and the wavelength was 630 nm.
Then, a hologram pattern having a different refractive index was fixed on the outer surface of the cylinder, and Al was deposited on the surface. This duplicate replica was a volume phase hologram on the side of the cylinder, and the reproduction efficiency of each image was 3%.

(Effect of the Invention) As described above, in the multiple hologram element of the present invention, since the recorded interference fringes develop on the three-dimensional side surface, interference with other recorded holograms is small, and the separation and resolution of images between multiple holograms are achieved. Are better than those multiplexed on a conventional plane.

In addition, since the hologram is dispersed over a wide surface by multiple reflection, the hologram is resistant to scratches and dirt on the recording surface, and is excellent in separation from other recorded images.

In addition, since it is basically possible to turn over a plane, a master hologram is created and then replicated by an appropriate method.
Is easy to make. This is the only method that can provide characteristics close to that of a volume hologram element, which cannot be duplicated in the past, and has the advantage of an extremely wide application range.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of the configuration of a multiplexed hologram element according to the present invention, FIG. 2 is a diagram showing the concept of conventional hologram recording, FIG. 3 is a diagram showing the concept of conventional hologram reproduction, and FIG. FIG. 5 is a diagram showing a concept of a conventional example of reproducing a multiplex hologram, FIG. 6 is a diagram showing a concept of an example of an improved reproduction of a conventional multiplex hologram recording, and FIG. FIG. 8 is a diagram showing the concept of an example of a volume multiplexed hologram, FIG. 8 is a diagram showing the concept of an example of a multiplexed hologram obtained by dividing a volume hologram into planes, and FIG. FIG. 10 (a) is a view showing another configuration example of the multiplexed hologram element of the present invention, and FIG. 10 (b) is a plan view of the multiplexed hologram element shown in FIG. 10 (a). FIG. 11 is a view showing a state, and FIG. It is a figure which shows a manufacturing process. 10, 11: Multiple hologram element 12: Reference light, 13, 14, Object light 15, 16: Interference fringe area 17: Area where overlapping interference fringes are recorded 18: Expanded medium surface 23 ... ... object light, 24 ... recording medium 25 ... object, 26 ... half mirror 31 ... reproduction light, 32 ... recording medium 33 ... virtual image by hologram reproduction 34 ... phase conjugate image 41 ... object light, 42 …… Reference light 43 …… Recording medium, 44 …… Interference fringes 51,54 …… Reproduction light, 52,55 …… Reproduction image 53,56 …… Multiple hologram, 57 …… Recording medium 61,64 …… Object light Reference light 63, 66 Hologram area 67 Hologram overlapping area 71 Volume hologram medium 72, 75 Object light 73 Reference light 74, 76 Volume hologram area 81 … Hologram recording medium, 82… Reference light 83, 84… Object light 85, 86, 87, 88… Interference fringe recording surface 111… Multiple hologram elements during recording 112… Multiple holograms developed on a plane Flat replica 114 ...... uneven reverse pattern 115 ...... multiplex hologram transfer medium 116 ...... multiplex hologram element planar replicas were stereoscopic reconstruction of the ram element surface 113 ...... multiplex hologram element.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Iwao Hatakeyama 1-6, Uchisaiwaicho, Chiyoda-ku, Tokyo Nippon Telegraph and Telephone Corporation (58) Field surveyed (Int. Cl. ⁷ , DB name) G02B 5 / 18,5 / 30,5 / 32 G03H 1/00-5/00

Claims (4)

(57) [Claims] 1. A multi-hologram element for recording a plurality of interference fringes formed by the interference of two light beams in the same element, wherein the multi-hologram element is constituted by a hollow tube-shaped total reflection type mirror, and A multiple hologram element, wherein a multiple hologram is formed on an inner surface portion. 2. A method for manufacturing a multiplex hologram element in which a plurality of interference fringes formed by interference of two light beams are recorded in the same element, a reflective film is deposited on a flexible substrate surface, and the surface of the reflective film is deposited. After inserting the recording medium in which the photoresist has been formed into the hollow cylindrical tube and pre-baking the photoresist, the reference laser light from the upper end face of the hollow cylindrical tube, the side from the side of the hollow cylindrical tube. A recording step of irradiating several types of object laser beams having an arbitrary angle with the reference laser beam so as to have a certain angle with respect to the center of the end surface of the hollow cylindrical tube, and recording a multiplex hologram on the photoresist. After taking out the recording medium on which the multiplexed hologram is recorded from the hollow cylindrical tube, developing it in a planar shape and developing it,
A development process for producing a multiplexed hologram master by post-baking; and a Ni stamper produced by applying a Ni plating to a multiplexed hologram forming surface of the multiplexed hologram master, and a hot press method using the Ni stamper, 2P (Photo A transfer step of transferring a multiplexed hologram formed on the Ni stamper surface to a flexible plastic substrate surface by, for example, a polymer method, and a reflective film deposited on the back surface of the multiplexed hologram transfer surface of the flexible plastic substrate. And inserting and fixing the replica multiple hologram element in the hollow cylindrical tube so that the reflection film is in close contact with the inner surface of the hollow cylindrical tube. Method. 3. A method for manufacturing a multiplex hologram element, in which a plurality of interference fringes formed by interference of two light beams are recorded in the same element, a reflective film is deposited on a flexible substrate surface, and the surface of the reflective film is formed. After inserting the recording medium in which the photoresist has been formed into the hollow cylindrical tube and pre-baking the photoresist, the reference laser light from the upper end face of the hollow cylindrical tube, the side from the side of the hollow cylindrical tube. A recording step of irradiating several types of laser beams having an arbitrary angle with the reference laser beam so as to have a certain angle with respect to the center of the end surface of the hollow cylindrical tube, and recording a multiplex hologram on the photoresist. After taking out the recording medium on which the multiplexed hologram is recorded from the hollow cylindrical tube, developing it in a planar shape and developing it,
A developing step for producing a multiplexed hologram master by post-baking; and applying a dye solution that absorbs a reproduction laser to a multiplexed hologram forming surface of the multiplexed hologram master to form an offset plate. By pressing the outer surface of the tube, the dye pattern of the multiple hologram is printed on the outer surface, a transfer step of drying and solidifying the dye pattern, a reflective film on the dye pattern forming surface of the transparent hollow cylindrical tube A method for producing a multiplexed hologram element, comprising the steps of: evaporating and further forming a protective film on the surface. 4. A method for manufacturing a multiplex hologram element in which a plurality of interference fringes formed by interference of two light beams are recorded in the same element, a reflective film is deposited on a flexible substrate surface, and the surface of the reflective film is deposited. After inserting the recording medium in which the photoresist has been formed into the hollow cylindrical tube and pre-baking the photoresist, the reference laser light from the upper end face of the hollow cylindrical tube, the side from the side of the hollow cylindrical tube. A recording step of irradiating several types of object laser beams having an arbitrary angle with the reference laser beam so as to have a certain angle with respect to the center of the end surface of the hollow cylindrical tube, and recording a multiplex hologram on the photoresist. After taking out the recording medium on which the multiplexed hologram is recorded from the hollow cylindrical tube, developing it in a planar shape and developing it,
Developing step for producing a multiplexed hologram master by post-baking, and applying a photocurable resin solution to a multiplexed hologram forming surface of the multiplexed hologram master to form an offset plate, and forming the offset plate into a transparent hollow cylindrical tube. By pressing against the outer surface, a photocurable resin pattern of the multiplexed hologram is formed on the outer surface, and the photocurable resin of the pattern portion is impregnated into the outer surface, and then the outer surface is irradiated with ultraviolet rays. Transferring the photocurable resin of the pattern portion to light, and forming the multiple hologram pattern having a different refractive index on the outer surface of the transparent hollow cylindrical tube; and forming a reflective film on the multiple hologram pattern formation surface. A method for producing a multiplexed hologram element, comprising the steps of: evaporating and further forming a protective film on the surface.