JP2001071700A - Sheet with latent image picture, printed matter, and written matter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize the easy judgment of authenticity or of whether forging or not by providing a latent image picture, which is transparent with naked eyes and visibly seen through a polarizing film and has polarizing properties different from the polarizing properties intrinsic to a latent image forming layer. SOLUTION: A sheet 1 having a latent image picture is formed by providing a latent image forming layer 13 having polarizing properties and a light scattering layer 15, the surface of which is matted, in the order named on a light reflecting layer 12. The latent image picture 23 forms some part of the latent image forming layer 13 having the polarizing properties and is latent image portion having the polarizing properties, which are different from the polarizing properties of the latent image forming layer 13 or is transparent with naked eyes and visibly seen through a polarizing film or the latent image picture. By seeing the sheet 1 with the latent image picture under the state being piled up with a polarizing film 14 thereabove, a picture, in which the latent image picture 23 can be seen as well as an ordinary printed portion 25, can be realized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet having a latent image for the purpose of displaying hidden characters and hidden patterns, and more particularly, to a method for easily determining whether a sheet is forged or not. A sheet having a latent image formed therein,
And a printed matter and a written matter using a sheet having the latent image.

[0002]

2. Description of the Related Art Conventionally, there have been various methods using a latent image as a hidden character or a hidden pattern. For example, 1) Hidden characters etc. are inserted using the gap of the line pitch,
A line drawing in which hidden characters appear by hiding the lines, 2) Print a transparent ink medium with a filler, and rub the part with a pencil. Pencil powder adheres to the printed part and the hidden characters There is a pencil out print (deco mat) that appears. However, since these latent images are deciphered when viewed closely, they are used for play rather than forgery prevention methods using full-scale latent images.

[0003] 3) A method for forming a latent image using a white or colorless and transparent irreversible thermosensitive coloring ink which develops color by applying heat requires a heat source device to display the latent image. Since the latent image cannot be erased once it has been displayed, its use is limited. 4) A method of displaying a latent image by printing a white ink containing a filler harder than a metal such as titanium oxide on a white paper and rubbing it with a coin or the like is performed by visually providing a mat-like varnish. Although the image is made invisible, the latent image can be displayed only once, so that its use is limited. That is, the above methods 3) and 4) are limited to one-time use.

[0004] Further, as a method for preventing forgery by a latent image which can be repeatedly displayed, 5) reversible thermosensitive coloring ink (thermochromic ink)
There is a method using. The thermochromic ink reversibly develops or decolors when heated, and returns to its original state after being left for a while. This ink is used as a latent image or for concealing an image, but its use is limited due to its low resistance, especially heat resistance. 6) Photochromic ink is an ink that develops color when irradiated with light, particularly ultraviolet light, and is used as a latent image by being used as a white or colorless transparent ink. Is limited. 7) Fluorescent ink is an ink that emits light when irradiated with ultraviolet light, and is used as a latent image by being used as a white or colorless transparent ink. And
The fluorescent ink is classified into an organic type and an inorganic type. The organic type emits light only when it is contained in a very small amount in the printing ink, but its use is limited due to its low light resistance. In addition, the inorganic type needs to be contained in a large amount in the printing ink (about 10 to 20%), and as a latent image, it is easy to visually recognize it. That is, the methods 5), 6) and 7) are restricted in terms of durability.

Another method for preventing forgery with a latent image that can be repeatedly displayed is 8) a method of forming a latent image by using moire (interference fringes) of halftone dots or lines. In this method, a latent image is formed by partially changing the pitch or angle of a halftone dot or a line, and an image appears by superimposing a halftone dot or a line of transparent film on the latent image in order. Things. In this method, the display can be easily repeated with the transparent film, and there is no limitation in terms of durability, but there is a problem that a complicated image cannot be formed.

Another method of preventing forgery using a latent image which can be repeatedly displayed is 9) a method using a latent image formed of magnetic ink. In this method, a latent image is formed by magnetizing a magnetic layer having a coercive force (approximately 300 Oe or more) capable of magnetic recording in a pattern, and the magnetized portion is imaged by sprinkling iron powder on the magnetic layer. It is a method of displaying as. However, in this method, the latent image can be easily rewritten and forged, and the process of displaying the latent image is complicated, and a specific detection device is required. 10) Form a latent image with ink that absorbs infrared light,
There is a method in which a layer that transmits infrared light but not visible light is provided on the latent image. However, in order to display the latent image, an infrared camera or the like is required, and the device becomes large. In addition, there is a method using an ink (IV ink) which is white or colorless in the visible region but absorbs in the infrared region. An infrared camera or the like is also required.

That is, the above methods 9) and 10) are methods capable of repeated display, and are not restricted in terms of durability and image definition, but a specific detection device is required for displaying a latent image. It is necessary.

[0008]

As described above, the above-mentioned methods using the latent image as a hidden character or a hidden pattern have different problems. The present invention has been made to solve the above-described problems, and in a sheet using a latent image as a hidden character or a hidden pattern, it is possible to perform authenticity determination many times, and the sheet is limited in terms of durability and image definition. Not, and
It is an object of the present invention to provide a sheet having a latent image, which does not require a specific detection device for the interpretation, and can easily determine the authenticity of the forgery. Also,
It is an object of the present invention to provide a printed matter and a written matter using a sheet having the latent image.

[0009]

SUMMARY OF THE INVENTION The present invention relates to a sheet having a latent image, wherein a latent image forming layer having a polarizing property is provided on a light reflecting layer. Is a sheet having a latent image provided with a latent image having a polarization property different from the polarization property, which is transparent and visible by a visual observation using a polarizing film.

The present invention also provides a sheet having a latent image according to the present invention, wherein the latent image forming layer is light-scattering.

The present invention also provides a sheet having a latent image according to the present invention, wherein the surface of the latent image forming layer has a matte tone.

Further, the present invention provides a sheet having a latent image according to the above-mentioned invention, wherein a light scattering layer is provided on the latent image forming layer.

The present invention also provides a sheet having a latent image according to the above-mentioned invention, wherein the surface of the light scattering layer has a matte tone.

Further, the present invention is a printed matter using the sheet having the latent image according to the above invention.

Further, the present invention is a writing object using the sheet having the latent image according to the above invention.

[0016]

Embodiments of the present invention will be described below. FIG. 1 is a plan view showing an embodiment of a sheet having a latent image according to the present invention. FIG.
It is sectional drawing which shows an Example in -X 'cross section. As shown in FIGS. 1 and 2, the sheet (1) having a latent image is provided on the light reflecting layer (12) with a latent image forming layer (1) having a polarizing property.
3) A mat-like light scattering layer (15) is provided on the surface. In FIG. 2, (23) is a part of the latent image forming layer (13) having a polarizing property, which is different from the polarizing property of the latent image forming layer (13) having a polarizing property and is transparent by naked eyes. This is a latent image portion having a polarizing property, that is, a latent image, which is visible by visual observation using a polarizing film.

In FIG. 2, reference numeral (25) denotes a normal printed portion, the surface of which is provided on the mat-like light scattering layer (15) and is visible with the naked eye. In this latent image (23), the polarization of the latent image forming layer (13) having a polarizing property is partially caused by heat, electricity, magnetic energy or the like in an image pattern. The part is oriented so as to have a polarization property different from the property. In FIG. 1, a sheet (1) having a latent image is such that the latent image (23) cannot be confirmed by naked eyes and only a normal printed portion (25) can be seen.

FIG. 3 is a plan view showing a state in which the latent image (23) of one embodiment of the sheet having the latent image shown in FIG. 1 is read. FIG. 4 is a cross-sectional view of FIG.
It is sectional drawing which shows the state at the time of reading the latent image (23) shown by X 'cross section. As shown in FIGS. 3 and 4, a polarizing film (14) is placed above the sheet (1) having a latent image.
The normal printing part (25)
The image (2) in which the latent image (23) is visible
3 ').

FIG. 5 is a sectional view showing another example of a sheet having a latent image according to the present invention. As shown in FIG.
The sheet (11) having the latent image is a light reflecting layer (12).
Is provided with a latent image forming layer (13A) having a polarizing property on one side of the surface and a light scattering layer (15A) having a matte surface, and a part of the latent image forming layer (13A) having a polarizing property is provided. A latent image portion having a polarizing property, which is different from the polarizing property of the latent image forming layer (13A) having a polarizing property, is transparent when viewed with the naked eye and is visible when viewed using a polarizing film, that is, a latent image image (23A) is provided.

On the other surface of the light reflecting layer (12), a latent image forming layer (13B) having a polarizing property and a light scattering layer (15B) having a matte surface are provided. A part of the latent image forming layer (13B) having a polarizer, which is different from the polarizing property of the latent image forming layer (13B) having a polarizing property, is transparent by naked eyes and visible by a polarizing film, A latent image portion having polarization, that is, a latent image image (23B) is provided. In FIG. 5, (25
A) and (25B) are ordinary printing portions provided on a mat-like light scattering layer (15A) and a mat-like light scattering layer (15B), respectively.

The light-reflecting layer is not particularly limited as long as it has light-reflecting properties. A vapor-deposited film of various metals and alloys, a sputtering film, and the like can be used. For example, Al, Cr, Ni, Cu, Ag as a metal
And alloys such as Pt-Rh and Ni-Cr.

Examples of the material for the latent image forming layer include polyolefin-based and polyester-based polymer materials. In the case of a polymer liquid crystal, the temperature is 80 to 200 ° C.
Those having a melting point of about the same and exhibiting thermotropic property are preferable, and examples thereof include polymer materials exhibiting thermotropic property such as polyester copolymer, polyether, polycarbonate, polyisocyanate, and polyglutamic acid ester. The polymer material exhibiting the thermotropic property can be formed by a known coating means such as a gravure printing method, a screen printing method, and a nozzle coater method.

Examples of the polarizing film include polymer polycrystalline types such as a PVA-iodine type, a dichroic dye type, a metal or metal compound containing type, and a polyene type in which iodine is absorbed in a stretched PVA film. In particular, PVA-iodine type,
The dichroic dye type is preferred. The circularly polarizing film is a film in which a quarter-wave retardation film is overlaid on the polarizing film.

In the latent image, a part of the latent image forming layer having a polarization property in advance has a polarization property different from the polarization property in advance due to external force such as heat, pressure, scratching, friction, light, electricity, and magnetism. It is a latent image portion oriented in a certain direction so as to have. As a method of forming the latent image, for example, hot stamping, thermal head, heating by laser, etc.
Scratching with a brush, sandpaper, sandblasting or the like is possible.

When the latent image forming layer is light scattering, or when the light scattering layer is provided on the latent image forming layer, specular reflection from the light reflecting layer is scattered, thereby improving the visibility of printing and writing. It will be. This light scattering layer can be obtained by roughening the surface of the latent image forming layer or applying a fine particle pigment such as titanium oxide.

When the surface of the latent image forming layer or the light scattering layer has a matte tone, printing or pen ink easily penetrates, thereby improving printability and writability. Also, carbon of a pencil is easily adhered and writability is improved. Is improved.

[0027]

The present invention will be described in detail with reference to the following examples. Example 1 A light reflecting layer was formed by depositing aluminum on one side of a 30 μm thick polyethylene sheet by vacuum evaporation to form a light reflecting layer, and the light reflecting layer surface and a 30 μm thick polyethylene not subjected to aluminum evaporation were formed. The sheet was laminated using ethylene vinyl acetate copolymer (EVA) as an adhesive. Both sides of the laminated sheet were rubbed in one direction with a roller having a plastic file having a roughness of 10 μm attached thereto, so that the entire surface was polarized. Next, masking was performed by screen printing using an acrylic resin in portions where the polarization property was desired to be left.

Subsequently, 3 μm in a direction perpendicular to the direction rubbed earlier.
m, the polarizability of the unmasked portion was erased, and after this depolarization treatment, the acrylic resin was peeled off. Next, the surface treatment ink was applied by a gravure coater at 2 μm to form a light scattering layer having a matte surface. Finally, a normal print image was provided by offset printing. The composition of the surface treatment ink used is shown below.

(Composition of surface treatment ink) Top coat varnish (Matte OP varnish 3H: manufactured by T & K TOKA Co., Ltd.) 90 parts by weight Titanium oxide (Titanium oxide A-120: manufactured by Sakai Chemical Industry Co., Ltd.) 10 Parts by weight

The sheet having the obtained latent image could not be visually recognized at all with the naked eye, but could be seen as a mere printed matter. However, the latent image appeared when the polarizing plate was overlapped. In addition, the surface became mat-like due to the titanium oxide filler, the printing characteristics and the writing characteristics were improved, and it was possible to easily write by printing or pencil.

[0031]

According to the present invention, there is provided a sheet having a latent image formed on a light reflection layer on which a latent image forming layer having a polarizing property is provided. Since a latent image having a polarizing property different from the polarizing property, which is visible by visual inspection using a film, is provided, the authenticity can be determined a large number of times, and is limited in terms of durability, image definition. In addition, a sheet having a latent image that does not require a specific detection device for its interpretation and can easily determine the authenticity of forgery is obtained.

Further, since the present invention is a printed matter using a sheet having the latent image, the authenticity can be determined many times, and there is no restriction in terms of durability and image definition, and
A printed matter using a sheet having a latent image, which does not require a specific detection device for its interpretation and can easily determine the authenticity of the forgery.

Further, the present invention is a handwritten article using the sheet having the latent image, so that the authenticity can be determined many times, and there is no restriction in terms of durability and image definition.
It is a handwritten article using a sheet having a latent image that does not require a specific detection device for its interpretation and can easily determine the authenticity of forgery.

[Brief description of the drawings]

FIG. 1 is a plan view showing an embodiment of a sheet having a latent image according to the present invention.

FIG. 2 is a cross-sectional view showing one embodiment along a line XX ′ in FIG. 1;

FIG. 3 is a plan view showing a state of reading the latent image of one embodiment of the sheet having the latent image shown in FIG. 1;

FIG. 4 is a cross-sectional view showing a state when a latent image shown by a XX ′ cross section in FIG. 3 is read.

FIG. 5 is a cross-sectional view illustrating another example of a sheet having a latent image according to the present invention.

[Explanation of symbols]

 1, 11 {sheet having latent image image 12} light reflection layer 13, 13A, 13B {latent image forming layer having polarization property 14} polarizing film 15, 15A, 15B} matte light Scattering layer 23, 23A, 23B {Latent image image 23 '} Visible image 25, 25A, 25B {Normal printing part

Claims (7)

[Claims] In a sheet having a latent image, a polarizing film is used as a latent image forming layer of a sheet having a polarizing image forming layer provided on a light reflecting layer. A sheet having a latent image, wherein the sheet is provided with a latent image having a polarization property different from the polarization property, which is visible with the naked eye. 2. A sheet having a latent image according to claim 1, wherein said latent image forming layer is light scattering. 3. The sheet having a latent image according to claim 2, wherein the surface of the latent image forming layer has a matte tone. 4. A sheet having a latent image according to claim 1, wherein a light scattering layer is provided on said latent image forming layer. 5. The sheet having a latent image according to claim 4, wherein the surface of the light scattering layer has a matte tone. 6. A printed material using a sheet having a latent image according to claim 1. 7. A writing article using the sheet having the latent image according to claim 1.