JP2959900B2 - Rainbow hologram discrimination method and information recording method using rainbow hologram - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for discriminating the authenticity of a rainbow hologram and an information recording method using the rainbow hologram, and more particularly, to an object used for recording a rainbow hologram separately from surface recorded information of the rainbow hologram itself. Record other information such as authenticity discrimination information depending on the position and shape of the slit-shaped opening to restrict light,
The present invention relates to a method for determining the authenticity of a rainbow hologram.

[0002]

2. Description of the Related Art Hitherto, a hologram such as a rainbow hologram has been adhered to a CD card or the like to guarantee its authenticity. This is because holograms are relatively difficult to forge.

Conventionally, in order to prevent forgery, the content of information such as an image directly recorded on a hologram has been devised to make it more difficult to forge.

[0004]

However, since the information directly recorded on the hologram is reproduced and displayed, there is a limit to how to prevent forgery. When the authenticity of the card is judged by the reader, the hologram does not contribute to the prevention of forgery at all. .

The present invention has been made in view of such a situation, and an object of the present invention is to provide a method of recording and reproducing a rainbow hologram, in which a rainbow hologram is recorded separately from information superficially recorded thereon. A method of recording different information according to the position and shape of the slit-shaped opening for limiting the object light to be used, reproducing the slit-shaped opening, and determining the authenticity of the hologram with a relatively simple device. To provide.

[0006]

A rainbow hologram genuineness discrimination method according to the present invention which achieves the above object, is reproduced when a rainbow hologram is illuminated with monochromatic light having a predetermined wavelength in a predetermined optical arrangement. The method is characterized in that the authenticity of a rainbow hologram is determined by detecting the shape and position of a reproduced image of a slit-shaped opening for restricting the object light used in the recording.

Another method of discriminating the authenticity of a rainbow hologram according to the present invention is a method of reproducing a multi-recorded multicolor rainbow hologram when it is illuminated with monochromatic light of a predetermined wavelength in a predetermined optical arrangement. A method for determining the authenticity of a multi-recording multicolor rainbow hologram by detecting the shapes and positions of a plurality of reconstructed images of a slit-shaped aperture for restricting an object beam used for recording. It is.

Further, another method of discriminating the authenticity of a rainbow hologram according to the present invention is that a specific point or a plurality of points of a multi-recording multicolor rainbow hologram are simultaneously or sequentially subjected to a predetermined optical arrangement to a single color of a predetermined wavelength. Diffraction light generated when illuminated with a thin beam of light is reproduced when illuminating the entire surface of the multiplex-recorded multicolor rainbow hologram, and is a slit-shaped aperture for limiting the object light used for those recordings. A plurality of reproduced images are detected at each position, and the detected intensity ratio is compared with a reference value to determine the authenticity of the multi-recording multicolor rainbow hologram. In this case, it is also possible to detect the diffracted light while scanning the multiple recording multicolor rainbow hologram with a narrow beam of monochromatic light.

Further, the information recording method using a rainbow hologram according to the present invention is characterized in that the multiplex-recorded multicolor rainbow hologram is reproduced when illuminated with monochromatic light of a predetermined wavelength in a predetermined optical arrangement. At the time of recording a multi-color rainbow hologram, the slits on the first-stage hologram for each color separation so that a plurality of reconstructed images of a slit-shaped opening for restricting the object light used at the time represent bar-code bit information. The method is characterized in that multiplex recording is performed by changing the position or shape of the opening in the shape of a circle, or the angle of the reference light at the time of recording the multicolor rainbow hologram.

[0010]

In the rainbow hologram authenticity discrimination method of the present invention, the object light used for recording is reproduced when the rainbow hologram is illuminated with monochromatic light of a predetermined wavelength in a predetermined optical arrangement. Determines authenticity based on information at the time of recording, which is different from the superficial recording information of the rainbow hologram, such as the shape, position, and intensity of the diffracted light of the reproduced image of the slit-shaped opening for limiting. So
The accuracy of authenticity determination is improved, and it becomes more difficult to forge a rainbow hologram.

In the information recording method using a rainbow hologram of the present invention, the position and the width of the slit-shaped opening to be superimposed on the first-stage hologram for each color separation are changed when the multi-color rainbow hologram is recorded. By performing multiplex recording by changing the angle of light, bit information such as a barcode can be recorded on the multiplex-recorded multicolor rainbow hologram. Information that does not exist can be additionally recorded, and can be used for authenticity discrimination information and the like.

[0012]

First, the principle of recording and reproducing a rainbow hologram will be briefly described with reference to FIG. First, as shown in FIG.
Then, the object light 15 from the subject 11 and the reference light 13 are recorded by causing them to interfere with each other on the photosensitive original plate 14 to create a Fresnel hologram. Next, as shown in FIG. 3B, a mask 20 having a slit-shaped opening 21 is superimposed on the Fresnel hologram 19 thus created and reproduced. The slit-shaped opening 21 of the mask 20 is elongated in the horizontal direction, and when the Fresnel hologram 19 is irradiated with the reproduction illumination light 16, three-dimensional information in the vertical direction is reduced. The light 17 forms a reproduced image 23 of the original image of the entire subject as a real image. The interference fringes between the diffracted light 17 and the reference light 18 are recorded on the photosensitive original plate 22 as an image hologram.

The hologram recorded on the photosensitive original plate 22 becomes a monochromatic rainbow hologram 28. That is,
When the rainbow hologram 28 is irradiated with white reproduction illumination light 24 as shown in FIG.
Along with 7, a reproduced image 25 of the mask 20 is formed at a different position for each wavelength. Therefore, from the viewpoint 30, the reproduced image 27 can be seen through the opening 26 of the slit image of the mask image 25 of a certain wavelength. Since unnecessary wavelength components do not pass through the aperture 26, a reproduced image can be observed in a single color.
Even when white light is used as reproduction illumination light, almost the same result as that of a reproduced image using monochromatic light can be obtained. When the viewpoint 30 is moved, the image moves to the image forming position of the aperture of the slit image with a different wavelength, so that a reproduced image with the different wavelength can be seen. Therefore, for reproduction of a predetermined wavelength, a reproduced image 27 of a single color can be observed from a certain range.

The above is a conventional method for producing a known monochromatic rainbow hologram. The Fresnel hologram 19 shown in FIG. 3B is illuminated with illumination light 12 of different wavelength or illumination light 12 from different directions. A multicolor rainbow hologram can be created by sequentially and multiplex-recording hologram patterns of a plurality of types of color separation images on the photosensitive original plate 22 using the created color separation Fresnel hologram. By irradiating the white reproduction light 24, multiple images of reproduction images of different colors can be obtained. Each of the reproduced images has a density corresponding to each primary color component of the subject (Japanese Patent Laid-Open No. 1-1249).
No. 3, No. 1-128085, Japanese Patent Application No. 1-293244
issue).

Next, the principle of the method for determining the authenticity of a rainbow hologram according to the present invention will be described. FIG.
As shown in FIG.
The angle of incidence θ ₂ of the reference beam 18 at the time of the second stage recording (FIG.
When illuminated in (b)), the reproduced image 4 of the slit at the time of recording is reproduced by the diffracted light 3. The image forming position of the slit image 4 is determined by the arrangement of the optical system when the rainbow hologram 1 is recorded (the incident angle θ ₁ of the principal ray of the diffracted light 17, the incident angle θ ₂ of the reference light 18 in FIG. It is uniquely determined by the distance L) between the mask 20 and the photosensitive original plate 22, the recording wavelength λ, the wavelength λ ′ of the reproduction illumination light, and the incident angle θ ₂ ′. Therefore, in the present invention, first, at the time of recording the rainbow hologram 1, the shape of the opening 21 of the mask 20 (FIG. 3B) which is superimposed and reproduced on the first-stage hologram 19, and the arrangement of the optical system (θ ₁ , θ ₂ , L) and the recording wavelength λ are selected to be specific ones. When the rainbow hologram including the rainbow hologram 1 recorded in this manner is reproduced, the monochromatic light 2 having the reproduction wavelength λ ′ having a specific relationship with the wavelength λ at the time of recording is used, and the incident angle of the reference light at the time of recording is used. θ
_The slit image 4 is reproduced by illuminating it at an incident angle θ ₂ ′ having a specific relationship with ₂ and whether or not the slit image 4 is reproduced in a predetermined shape and position is detected by, for example, a CCD camera or the like. By detecting the rainbow hologram, the authenticity of the target rainbow hologram is determined.

Furthermore, the rainbow hologram, as shown in FIG. 2, in the case of multicolor rainbow hologram 10, from the recording principle, when illuminated by the monochromatic light 2, a plurality of slit images ₄₁ to ₄ are reproduced. The number corresponds to the number of superimposed color separation images. The image forming positions are determined by the arrangement of the optical system when the rainbow hologram 10 is recorded (the incident angle θ ₁ of the principal ray of the diffracted light 17, the incident angle θ ₂ of the reference light 18, the mask 20). Is uniquely determined by the distance L) between the image and the photosensitive original plate 22 and the recording wavelength λ. Therefore, whether or not the slit image ₄₁ to ₄ pattern is given, for example, by detecting by the detecting means such as a CCD camera, it is possible to determine the authenticity of the multicolor rainbow hologram 10 as well.

By the way, when reproduction is performed at a predetermined wavelength,
Slit image ₄₁ to ₄ patterns can also be to represent the bit information such as a bar code. For this purpose, when recording such a multicolor rainbow hologram 10, for example, when recording each color separation image, the position and opening width of a slit-shaped mask to be superimposed on the first-stage color separation hologram are changed. Alternatively, the angle of the reference light is changed. In this case, the bit information by the slit image ₄₁ to _four patterns, it is possible to record other desired information not only authenticity discrimination.

Now, as apparent from FIGS. 3B and 3C, the rainbow hologram is recorded in a form similar to an image hologram. Thus, when irradiated with monochromatic illumination light 2 is limited to a partial area of the multicolor rainbow hologram 10 as shown in FIG. 2, the light is diffracted into each area of the slit image ₄₁ to ₄ becomes always equal Instead, more light is diffracted into a particular slit image area corresponding to the color of the illuminated image portion. Accordingly, as shown in FIG. 2, for example, light-receiving elements 5 ₁ to 5 ₄ each slit image 4 ₁
Arranged to 4 ₄ position, against sequentially or simultaneously to a specific point or points of multicolor rainbow hologram 10 narrowly focused monochromatic illumination light 2 is detected by the light receiving elements 5 ₁ to 5 ₄ at that time By comparing the diffracted light intensity ratio with a reference numerical value, the authenticity of the multicolor rainbow hologram 10 can be determined with higher accuracy. Incidentally, the thin illumination light multicolor rainbow hologram 10 on a particular scan pattern (raster scan, vortex scanning, etc.) may be caused to scan in accordance with, in this case, the waveform signals from the light receiving elements 5 ₁ to 5 ₄ Is obtained, and by comparing this waveform with the reference waveform, the authenticity is determined.

Although the method for determining the authenticity of a rainbow hologram and the method for recording information using a rainbow hologram according to the present invention have been described based on some embodiments, the present invention is not limited to these embodiments, and various modifications may be made. It is possible.

[0020]

As is apparent from the above description, according to the method for determining the authenticity of a rainbow hologram according to the present invention, the rainbow hologram is reproduced when illuminated with monochromatic light of a predetermined wavelength in a predetermined optical arrangement. The invisible recording, which is different from the superficial recording information of the rainbow hologram, such as the shape, position, and the intensity of the diffracted light of the reconstructed image of the slit-shaped aperture used to limit the object light used for the recording Since the authenticity is determined based on the information of the time, the accuracy of the authenticity determination is improved, and it becomes more difficult to forge the rainbow hologram.

According to the information recording method using a rainbow hologram of the present invention, when recording a multicolor rainbow hologram, the position and the width of the slit-shaped opening to be superimposed on the hologram of the first stage of each color separation are changed. By performing multiplex recording by changing the angle of light, bit information such as a barcode can be recorded on the multiplex-recorded multicolor rainbow hologram. Information that does not exist can be additionally recorded, and can be used for authenticity discrimination information and the like.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining the principle of a rainbow hologram authenticity discrimination method according to the present invention.

FIG. 2 is a diagram showing how a plurality of slit images are reproduced from a multicolor rainbow hologram.

FIG. 3 is a diagram illustrating the principle of recording and reproducing a rainbow hologram.

[Explanation of symbols]

1 ... monochromatic rainbow hologram 2 ... monochromatic light 3 ... diffracted light 4 ... slit image ₄₁ to ₄ ... slit image 5 ₁ to 5 ₄ ... light receiving element 10 ... multicolor rainbow hologram 11 ... object 12 ... illumination light 13 ... reference light Reference Signs List 14 photosensitive original plate 15 object light 16 reproduction illumination light 17 diffracted light 18 reference light 19 Fresnel hologram 20 mask 21 slit opening 22 photosensitive original plate 23 reproduced image 24 reproduction illumination light 25 mask image 26 ... slit image aperture 27 ... reconstructed image 28 ... monochromatic rainbow hologram 30 ... viewpoint

Claims (5)

(57) [Claims] 1. A rainbow hologram is reproduced when illuminated with monochromatic light of a predetermined wavelength in a predetermined optical arrangement ,
Slit to limit the object light used for the recording
By detecting the shape and position of the reconstructed image of the aperture
A method for determining the authenticity of a rainbow hologram, comprising determining the authenticity of the rainbow hologram. 2. When a multi-recording multicolor rainbow hologram is illuminated with monochromatic light of a predetermined wavelength in a predetermined optical arrangement.
Restricts the object light used for those recordings that are played back
A rainbow hologram genuineness discriminating method comprising detecting the shape and position of a plurality of reproduced images of a slit-shaped opening for detecting the authenticity of a multiplex holographic rainbow hologram. 3. A diffracted light generated when one or more specific points of the multi-recording multicolor rainbow hologram are illuminated simultaneously or sequentially with a narrow beam of monochromatic light having a predetermined wavelength in a predetermined optical arrangement. These recordings are reproduced when the entire surface of the multiplex recording multicolor rainbow hologram is illuminated .
Of a slit-shaped aperture to limit the object light used
A method for determining the authenticity of a rainbow hologram, comprising detecting at each position of a plurality of reproduced images and comparing the detected intensity ratio with a reference value to determine the authenticity of the multiplex holographic rainbow hologram. 4. The method according to claim 3, wherein the diffracted light is detected while scanning the multiple-recording multicolor rainbow hologram with the narrow beam of the monochromatic light. 5. An object beam used for recording a multicolored rainbow hologram, which is reproduced when the multiplex-recorded multicolor rainbow hologram is illuminated with monochromatic light having a predetermined wavelength in a predetermined optical arrangement.
During recording of a multicolor rainbow hologram, the position or shape of the slit-shaped opening on the hologram of the first stage of each color separation so that a plurality of reproduced images of the slit-shaped opening for limiting represent barcode-shaped bit information. Alternatively, an information recording method using a rainbow hologram, wherein the multiplexed recording is performed by changing the angle of the reference light at the time of recording the multicolor rainbow hologram.