JPH06202539A - Hologram and information pattern reproducing apparatus for handling the hologram - Google Patents

Abstract

(57) [Abstract] [Purpose] A hologram is irradiated with laser light to copy the information pattern recorded on the hologram onto another photosensitive material. A playback device is provided. [Structure] When an information pattern is decomposed into a plurality of divided images with different directions of interference fringes and recorded in an information recording area of a hologram, even if laser light is incident from one direction, only a part of the information pattern can be dead copied. Therefore, it is difficult to make a complete dead copy of the information pattern. In addition, reproduction of the recorded information pattern of the hologram is performed by simultaneously entering a plurality of laser beams in accordance with the directions of the interference fringes of the plurality of divided images and forming an image on the image forming means.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optically readable hologram and an information pattern reproducing apparatus for handling the hologram.

[0002]

2. Description of the Related Art A hologram is a kind of recording medium utilizing interference fringes having a certain directionality. And because it can record a three-dimensional image, it is used as a display, and due to the difficulty of manufacturing (manufacturing requires special materials such as laser light source, photosensitive material, etc.), it is attached to the surface of securities such as cards. However, it is also used to judge the authenticity of securities.

The authenticity determination of securities having a hologram will be described in detail below by taking a card as an example. A card having a hologram is manufactured by pressing a hologram transfer foil onto a card substrate made of plastic such as vinyl chloride, and sticking the hologram. In addition, the hologram has characters,
Information patterns such as numbers, pictures of three-dimensional objects, and diffraction gratings are formed.

There are several authenticity determination methods, but the most typical method is visual confirmation of the information pattern of the hologram. That is, the hologram on the surface of the card can be directly viewed, or the hologram can be irradiated with light in the visible wavelength range to form an image of the reproduced information pattern on an image plane such as frosted glass.
The authenticity of the hologram, that is, the authenticity of the card is visually determined.

[0005]

However, in the conventional hologram, the interference fringes have a certain directionality, and for a person having knowledge of the hologram, the laser beam is applied to the authentic hologram so that the hologram is recorded in the hologram. There is a problem that it is easy to forge by copying the information pattern onto another photosensitive material, so-called dead copy.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a hologram for which dead copy is difficult and an information pattern reproducing apparatus for handling the hologram.

[0007]

The invention according to claim 1 is composed of a plurality of areas for recording a plurality of divided images obtained by decomposing one information pattern, and includes interference fringes of the plurality of areas. It is a hologram characterized by having an information recording area whose directionality is different for each divided image.

According to a second aspect of the invention, there is provided a hologram information pattern reproducing apparatus according to the first aspect,
It is possible to form a plurality of divided images as one information pattern, and it is possible to make laser light incident on the image forming means located above the hologram and the information recording area of the hologram, and to reflect it at the information recording area. The reproducing apparatus for a hologram information pattern is characterized in that it has a plurality of laser light incidence means located at a portion where the laser light is focused on the imaging means.

[0009]

According to the first aspect of the invention, the information pattern is decomposed into a plurality of divided images in which the directionality of the interference fringes is different and is recorded in the information recording area of the hologram, so that the laser beam is incident from one direction. However, only a part of the information pattern can be dead copied, and complete dead copy of the information pattern is difficult.

According to the invention of claim 2, claim 1
When reproducing the recorded information pattern of the described hologram (judgment of authenticity), a plurality of laser beams are simultaneously incident according to the directions of the interference fringes of a plurality of divided images, and imaged as one information pattern on the image forming means. Can be made.

[0011]

EXAMPLE An example according to the present invention will be described in detail below.
The hologram according to the present invention is basically a reflection type hologram having an information recording area including a Fresnel type and a Fourier transform type, but as a further feature, the information recording area of the hologram is obtained by decomposing one information pattern. It is composed of a plurality of areas for recording the obtained plurality of divided images, and the directionality of the interference fringes of the plurality of areas is different for each divided image.

That is, in the case of dead copying a hologram having a plurality of interference fringes having different directivities, it is necessary to perform dead copying by the number corresponding to the number of directions of the interference fringes.
Moreover, since it is necessary to irradiate the laser from the directions corresponding to the respective directions, it is practically difficult.

Hereinafter, a method of photographing a hologram when one information pattern is divided into three (for convenience, A, B, and C) will be exemplified and described in detail.

FIG. 1 is an explanatory view schematically showing the relationship between an information pattern and divided images. In this embodiment, the information pattern is three divided images of A, B, and C, and a transparent original is created. The information pattern may be either a halftone image or a continuous tone image.

FIG. 2 is an explanatory view showing an example of a method of photographing a hologram using the transparent original. In the drawing, the transparent original (4) of the divided image (A) and the diffusion plate (5) are overlapped on the upper part, and the mask (3) for the divided image (A) and the photosensitive material ( The supports (1) coated with 2) are arranged in an overlapping state. When the incident light (11) is incident from above in such a state, it is diffused by the diffusion plate (5) and selectively transmits the transparent original (5).
The light transmitted through the transparent original (5) is called object light (12). The object light (12) is a reference light (1
3) and interference fringes are recorded on the photosensitive material (2) located below the opening of the mask.

FIG. 3 shows a mask for divided images used in the above photographing method. The shape and the number of areas of the mask for the divided image are not limited to the above.

Since the same number of masks for divided images as the number of divided information patterns are required, three masks are prepared in this embodiment. Also, each mask has two hexagonal openings,
Each corresponds to one area. In addition, one hexagon (area) has a size inscribed in a circle having a diameter of 0.2 mm.

Next, the transparent original is replaced with the one for the divided image (B), the mask for the divided image is replaced with the mask for the divided image (B), and the reference light is made incident from the direction of 1 o'clock, and interference fringes are similarly recorded. did.

Finally, the transparent original is replaced with the one for the divided image (C), the divided image mask is replaced with the mask for the divided image (C), and the reference light is incident from the direction of 5 o'clock, and the interference fringes are similarly recorded. After development, a master hologram was obtained after development.

Although a known photographic optical system can be used, since the reproduced divided images all have the same size and must be reproduced at the same position, the size of the transparent original and the incident angle of the reference light are used. Need to be designed and adjusted by calculation.

The production of the hologram will be described in detail below with reference to FIG. A metal stamper for producing a hologram was produced from the above master hologram by a known electroforming operation.

The metal stamper was thermocompression bonded to a support film (22) having a hologram forming layer (23) made of a thermoplastic resin to emboss the master hologram to form a relief pattern in an information recording area.

Then, a reflective layer (24) was formed by vapor deposition of Al on the sheet on which the relief pattern of the information recording area was formed. Next, the pressure-sensitive adhesive layer (25) was formed by the gravure coating method, and the release paper (26) was attached. Finally, the sheet is punched and the hologram (2
1) was finished in the shape of a label.

FIG. 5 is an explanatory plan view showing the hologram of this embodiment. This hologram (21) has an information recording area composed of six areas on the same plane. The divided image (A) is divided into two (31) areas and the divided image (B) is divided into two (32) areas. The divided image (C) has two (3
It is recorded in the area 3). The interference fringes in the area have different directivities.

When a laser beam was incident on this hologram from one direction to attempt a dead copy, only a part of the information pattern could be reproduced.

A reproduction apparatus for reproducing the information pattern of the hologram (21) (hereinafter, simply referred to as a reproduction apparatus) will be described with reference to FIGS.
Will be described.

The main part of the reproducing apparatus according to the present invention can form a plurality of divided images as one information pattern, and an image forming means located above the hologram and a laser in the information recording area of the hologram. This is to have a plurality of laser light incident means that can enter light and that is located at a portion where the laser light reflected by the information recording area forms an image on the image forming means.

First, the laser light incident means will be described with reference to FIG. One of the laser light incident means is located at a position where the laser light can be incident on the information recording area of the hologram and the laser light reflected on the information recording area can be imaged on the image forming means.

Further, the laser beam incidence means is required for the number of divisions of the information pattern (three divisions in this embodiment), and the directions are different (7 o'clock, 9 o'clock, 1 o'clock in this embodiment).
Laser light is incident on the information recording area of the hologram from the direction of 1 o'clock).

The plurality of laser light incidence means of this embodiment obtain a plurality of laser lights from one laser (light source) using a mirror.
Needless to say, the same result can be obtained by using a plurality of laser beams.

The image forming means is a kind of screen for projecting the information pattern. The image forming means may be either a transmissive type for observing the transmitted laser light or a reflective type for observing the reflected laser light, but the transmissive type is preferable from the viewpoint of easy visual observation. Frosted glass (41) can be used as the transmissive screen.

Further, the operation of the reproducing apparatus will be described in detail. The laser (51), which is the light source of the reproducing device used in this embodiment, is
It is a He-Ne laser with a peak wavelength of 633 nm. The laser light (52) emitted from the laser (51) is
The mirror (53) is used to decompose into a, b, and c, and another mirror is used for the (21) information recording area of the hologram.
It was incident from the direction of 7 o'clock, 9 o'clock, and 11 o'clock (see FIG. 7).
Due to the area (31) of the divided image (A), the laser light from the direction of 9 o'clock (b) was reflected upward, and the divided image (A) was formed on the image forming means.

Similarly, the laser light from the 7 o'clock (a) direction is reflected upward by the area (32) of the divided image (B), and the divided image (B) is formed on the image forming means. Due to the area (33) of the divided image (C), the laser light from the direction of 11:00 (c) was reflected upward, and the divided image (C) was formed on the image forming means.

When the image forming means (frosted glass) was observed from above the reproducing device, the information pattern could be confirmed.

[0035]

As described above, according to the hologram of the present invention, the information pattern is decomposed into a plurality of divided images having different directionalities of the interference fringes and recorded in the information recording area of the hologram. Even if laser light is incident from one direction, only a part of the information pattern can be dead copied,
Complete dead copying of information patterns is difficult.

Further, according to the hologram information pattern reproducing apparatus according to the present invention, when reproducing (authenticity determination) the recorded information pattern of the hologram, a plurality of plural pieces are divided in accordance with the directions of the interference fringes of the divided images. It is possible to simultaneously enter laser light and form an image on the image forming means as one information pattern.

Therefore, it is possible to determine whether the information pattern is correctly reproduced or not, and whether or not the information pattern is reproduced.

[0038]

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an example of a relationship between an information pattern and a divided image according to the present invention.

FIG. 2 is an explanatory diagram showing an example of a hologram photographing method according to the present invention.

FIG. 3 is an explanatory view showing an example of a divided image mask used for photographing a hologram according to the present invention.

FIG. 4 is an explanatory diagram showing an example of a cross section of a hologram according to the present invention.

FIG. 5 is a plan view showing an example of a hologram according to the present invention.

FIG. 6 is an explanatory diagram showing an example of an information pattern reproducing apparatus according to the present invention.

FIG. 7 is an explanatory diagram showing a hologram reproducing method according to the present invention.

FIG. 8 is an explanatory view showing an example of a laser incidence means of the information pattern reproducing apparatus according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Support 2 Photosensitive material 3 Mask 4 Transparent original 5 Diffusion plate 11 Incident light 12 Object light 13 Reference light 21 Hologram 22 Support film 23 Hologram forming layer 24 Reflective layer 25 Adhesive layer 26 Release paper 31 Area of divided image (A) 32 area of divided image (B) 33 area of divided image (C) 41 ground glass 51 laser 52 laser light 53 mirror

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Akihiko Kobayashi 1-5-1, Taito, Taito-ku, Tokyo Toppan Printing Co., Ltd.

Claims (2)

[Claims] 1. An information recording area comprising a plurality of areas in which a plurality of divided images obtained by decomposing one information pattern are recorded, and the directionality of interference fringes of the plurality of areas is different for each divided image. A hologram characterized by having. 2. An information recording area which comprises a plurality of areas for recording a plurality of divided images obtained by dividing one information pattern, and in which the directionality of interference fringes of the plurality of areas is different for each divided image. A reproducing apparatus for a hologram information pattern, which is capable of forming a plurality of divided images as one information pattern, and an image forming unit located above the hologram, and a laser beam on an information recording area of the hologram. An information pattern reproducing apparatus for hologram, comprising a plurality of laser light incident means which can be made incident and are located at a portion where the laser light reflected on the information recording area is imaged on said image forming means.