JP2007163730A - Method of producing hologram and hologram produced by the method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of easily producing a hologram containing information that can not be observed under normal illumination, and to provide a hologram produced by the method. <P>SOLUTION: The method is characterized in that: a hologram H1 in a first step is recorded by allowing object light 1 and reference light 2 to simultaneously enter a recording material 11 and performing hologram recording; pattern information 12 is placed near the face of the hologram H1 of the first step upon producing a hologram H2 in a second step; the hologram H1 in the first step is irradiated with reproducing illumination light 3 while the pattern information 12 is simultaneously irradiated with the reproducing illumination light 3 to reproduce an object image O' from the hologram H1 of the first step and to generate object light from the pattern information 12; a hologram recording material 21 in the second step is placed near the reproduced object image and records the object image O' and the pattern information 12 as a hologram to thereby record them as the hologram H2 in the second step. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a hologram manufacturing method and a hologram manufactured by the method, and more particularly, to a method of manufacturing a highly secure hologram that enables authenticity determination and is difficult to counterfeit, and a hologram manufactured by the method.

It is known that a hologram is produced as a volume type image hologram and hologram recording is performed by a two-step method in order to enable observation of a 3D (three-dimensional) image under normal illumination (Non-patent Document 1). In addition, a method for producing a hologram having excellent security and design by recording a plane pattern image simultaneously in such a volume type image hologram is also known (Patent Document 1).
JP 2004-94202 A Toshihiro Kubota "Introduction to Holography-Principles and Practice", p. 47-48 (November 20, 1995, Asakura Shoten)

  In the method described in Patent Document 1, a hologram obtained at the second stage by the two-step method is used as one original plate, and another hologram on which a plane pattern image is recorded by a special method is overlaid on the hologram. A complicated method of superimposing different hologram sensitive materials and duplicating them by the hologram duplicating method is employed, and a hologram with high security cannot always be obtained by a simple method.

  The present invention has been made in view of such a situation in the prior art, and an object thereof is to produce a hologram including information (cover information) that cannot be observed under normal illumination by a simple method. And a hologram produced by the method.

The hologram manufacturing method of the present invention that achieves the above object records a first-stage hologram by simultaneously recording an object beam and a reference beam on a hologram recording material, and records the first-stage hologram from the recorded first-stage hologram. In a hologram manufacturing method in which an object image is reproduced and a hologram recording material in the second stage is arranged in the vicinity of the reproduced object image and recorded as a reflection type or transmission type hologram,
When producing the second stage hologram, pattern information is arranged near the surface of the first stage hologram, and the first stage hologram is irradiated with the reproduction illumination light so that the reproduction illumination light simultaneously strikes the pattern information. Then, the object image is reproduced from the hologram of the first stage, the object light is generated from the pattern information, the hologram recording material of the second stage is arranged in the vicinity of the reproduced object image, and the object image and the pattern information are holograms. It is a method characterized by recording as a second stage hologram by recording.

  In this case, it is desirable that the second stage hologram is recorded as a volume hologram.

  In addition, it is desirable to use substantially parallel light as reference light used when recording the first stage hologram and the second stage hologram.

  In the hologram of the present invention, when a predetermined reproduction illumination light is irradiated, an object image is reproduced in the vicinity of the hologram surface, and a window and pattern information arranged in the window are located at a predetermined distance from the hologram surface. It is recorded so as to be reproduced.

  In this case, it is desirable to consist of a volume hologram.

  According to the present invention, apart from object information recorded as an image hologram, pattern information as covert information can be recorded simultaneously at a position away from the hologram surface, and includes pattern information that cannot be observed under normal illumination. A hologram can be produced. When the hologram is observed with coherent light, characters, numbers, symbols, etc., which are pattern information, can be observed apart from the object information apart from the object information, so whether such pattern information can be observed under coherent light illumination. As a result, the authenticity of the hologram can be determined, and a highly secure hologram that is difficult to forge can be produced. In addition, it is not necessary to produce a hologram on which covert information is recorded, and it is not necessary to produce holograms by superimposing them.

  Hereinafter, the hologram production method of the present invention and the produced hologram will be described based on examples.

  When producing a volume hologram by a two-step method, the hologram production method of the present invention produces a first-stage hologram (hereinafter referred to as an H1 hologram) when producing a second-stage hologram (hereinafter referred to as an H2 hologram). The pattern information such as letters, numbers, symbols, etc. is arranged in the vicinity of the surface), and the reproduction illumination light is applied to the H1 hologram so that the reproduction illumination light is simultaneously applied to the pattern information. The hologram recording material for the second stage hologram is arranged in the vicinity of the reproduced object image and recorded as a reflection type or transmission type volume hologram.

  Hereinafter, description will be given with reference to the drawings. FIG. 1 is a side view showing a first-stage H1 hologram imaging arrangement (a) and a second-stage H2 hologram imaging arrangement (b) when producing a hologram by a two-step method according to the present invention. is there. 2A is a perspective view corresponding to FIG. 1B, and FIG. 2B is a front view of the H1 hologram in which pattern information is arranged.

  Using an H1 hologram recording photosensitive material 11 such as a photopolymer or a silver salt material, as shown in FIG. 1 (a), the surface of the object (here, shown in a cube) O recorded on the hologram of the present invention. Then, the photosensitive material 11 is arranged. Then, the object O is illuminated with a laser beam having a predetermined wavelength so that the object light 1 scattered by the object O is incident on the photosensitive material 11, and the surface of the photosensitive material 11 is coherent with the object light 1 at an incident angle θ. Reference light 2 consisting of parallel light from a light source is simultaneously incident to expose the hologram of the object O on the photosensitive material 11. The photosensitive material 11 on which the hologram is exposed is post-processed to produce an H1 hologram 11. Here, the photosensitive material 11 and the H1 hologram 11 are denoted by the same reference numeral 11.

  Next, as shown in FIG. 2B, pattern information 12 such as letters, numbers, symbols, etc. is arranged on a part of the surface of the obtained H1 hologram 11 or in the vicinity thereof, for example, a part of the periphery thereof. To do. The pattern information 12 may be directly provided by a method such as writing on the surface of the H1 hologram 11 or recording the pattern information 12 on the photosensitive material 11 when recording the hologram on the H1 hologram 11, A transparent sheet or the like on which pattern information 12 such as predetermined characters, numbers, and symbols is drawn may be arranged on the surface of the H1 hologram 11 or in the vicinity thereof. Then, on the H1 hologram 11 in which such pattern information 12 is arranged, as shown in FIG. 1B and FIG. 2A, the reproduction illumination light 3 traveling opposite to the reference light 2 at the time of recording is converted into the H1 hologram. 11 is incident from the side opposite to the side on which the reference light 2 is incident during recording. At that time, the reproduction illumination light 3 is incident so as to illuminate the pattern information 12 as well. Then, diffracted light 4 is generated from the H1 hologram 11, and an image O 'of the object O is reproduced and formed at the same position as the relative position of the 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 made of a photopolymer, a silver salt material, or the like is disposed in the vicinity of the position where the image O ′ of the object O is formed, and from the same light source that can interfere with the reproduction illumination light 3. The reference light 5 made up of the parallel light is incident simultaneously at an arbitrary incident angle from the opposite side or the same side as the diffracted light 4 to expose the second stage H2 hologram in the photosensitive material 21. At this time, scattered light or diffracted light is generated from the pattern information 12 irradiated with the reproduction illumination light 3, and the scattered light or diffracted light becomes object light and interferes with the reference light 5. It is exposed as a hologram. The photosensitive material 21 on which the second stage H2 hologram has been exposed is post-processed to produce the H2 hologram 21. Here, the photosensitive material 21 and the H2 hologram 21 are denoted by the same reference numeral 21.

  The H2 hologram 21 recorded as described above is a volume hologram. In the case of FIG. 2 in which the reference light 5 is incident from the opposite side to the diffracted light 4, the H2 hologram 21 is recorded as a reflection hologram. When entering from the same side, it is recorded as a transmission hologram.

  As shown in the side view of FIG. 3A and the perspective view of FIG. 3B, the reproduction illumination light 6 having high coherency that travels opposite to the reference light 5 at the time of recording is recorded on the H2 hologram 21 recorded in this way. When the light is incident on the H2 hologram 21 from the side opposite to the reference light 5 at the time of recording, the image O ″ of the image O ′ of the object O is reproduced in the vicinity of the H2 hologram 21 by the diffracted light 7 and the original A window 25 having the same size as the recording surface of the H1 hologram 11 is reproduced at the position of the H1 hologram 11, and an image 12 'of the pattern information 12 is also reproduced in the window 25. Therefore, a predetermined direction (reference for recording) When the coherent light 6 is irradiated in the opposite direction to the light 5), the observer sees the image O ″ of the object O in the vicinity of the H2 hologram 21 and the pattern information 12 in the window 25 spaced from the H2 hologram 21. Image 12 'can be observed.

  However, under reproduction illumination light 6 with low coherency such as illumination light from a fluorescent lamp or the like, the image 12 ′ of the pattern information 12 reproduced at the position of the window 25 separated from the surface of the H2 hologram 21 can be defocused and decomposed. I can't see.

  Therefore, when a hologram 21 including an image 12 ′ of the pattern information 12 that cannot be observed under normal illumination is produced, and the hologram 21 is reproduced with coherent light such as laser light or light with high parallelism such as sunlight. In addition to the image O ″ of the object O, characters, numbers, symbols, etc., which are the image 12 ′ of the pattern information 12 can be observed at positions away from the hologram 21, so such pattern information can be obtained under coherent light or sunlight illumination. The authenticity of the hologram 21 can be determined depending on whether or not the 12 images 12 'can be observed.

  In the above, the pattern information 12 such as letters, numbers, symbols, etc. is difficult to be found as fine patterns are difficult to forge, and the security is improved. Further, the arrangement position of the pattern information 12 on the surface of the H1 hologram 11 is not limited to the periphery of the pattern information 12 as long as the pattern information 12 is a fine pattern.

  In the arrangement of FIG. 1A, when divergent light is used as the reference light 2 when the H1 hologram 11 is photographed, it converges as the reproduction illumination light 3 when the H2 hologram 21 shown in FIGS. Light must be used, and it is necessary to generate convergent light that covers the entire area of the photosensitive material 11 using a convex lens having a larger aperture than that of the photosensitive material 11, and the recording apparatus becomes expensive. Therefore, by using parallel light as the reference light 2 and the reproduction illumination light 3, a lens or a parabolic mirror having the same size as that of the photosensitive material 11 may be used.

  As described above, the hologram manufacturing method of the present invention and the hologram manufactured by the method have been described based on the embodiments. However, the present invention is not limited to these embodiments, and various modifications can be made.

It is a side view which shows the imaging arrangement (a) of the 1st step H1 hologram at the time of producing a hologram by the 2 step method based on this invention, and the imaging arrangement (b) of the 2nd step H2 hologram. It is the perspective view (a) corresponding to FIG.1 (b), and the front view (b) of H1 hologram which arrange | positions pattern information. It is the side view (a) and perspective view (b) for demonstrating the effect | action of the produced hologram.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Object light 2 ... Reference light 3 ... Reproduction illumination light 4 ... Diffraction light 5 ... Reference light 6 ... Reproduction illumination light 11 ... Photosensitive material for H1 hologram recording (H1 hologram)
12 ... Pattern information 12 '... Pattern information image 21 ... H2 hologram recording photosensitive material (H2 hologram)
25 ... Window O ... Object O '... Object image

Claims (5)

The first-stage hologram is recorded by recording the hologram with the object light and the reference light simultaneously incident on the hologram recording material, the object image is reproduced from the recorded first-stage hologram, and 2 near the reproduced object image. In the hologram production method in which the hologram recording material at the stage is arranged and recorded as a reflection type or transmission type hologram,
When producing the second stage hologram, pattern information is arranged near the surface of the first stage hologram, and the first stage hologram is irradiated with the reproduction illumination light so that the reproduction illumination light simultaneously strikes the pattern information. Then, the object image is reproduced from the hologram of the first stage, the object light is generated from the pattern information, the hologram recording material of the second stage is arranged in the vicinity of the reproduced object image, and the object image and the pattern information are holograms. A hologram manufacturing method comprising recording as a second-stage hologram by recording. The hologram production method according to claim 1, wherein the second stage hologram is recorded as a volume hologram. 3. The hologram manufacturing method according to claim 1, wherein substantially parallel light is used as reference light used for recording the first-stage hologram and the second-stage hologram. Recording is performed so that an object image is reproduced in the vicinity of the hologram surface and a window and pattern information arranged in the window are reproduced at a position spaced by a predetermined distance from the hologram surface when a predetermined reproduction illumination light is irradiated. Hologram characterized by being made. The hologram according to claim 4, comprising a volume hologram.

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