RU2728480C1 - Method of counterfeit protection of securities and id with sheet material containing diffraction gratings - Google Patents

Abstract

FIELD: printing equipment.

SUBSTANCE: invention relates to special types of printing and enables to obtain an original image inside sheet paper for counterfeit protection of security papers. In compliance with this invention, green paper is used to insert sheet paper into said sheet from laser-transparent plastic, on opposite surfaces of which there are continuous diffusion gratings deepened in its surface. Metal-coated diffraction grating is successively coated on one side of the filament with a layer of plastic which is transparent to laser radiation and a metal layer. Then, the specified points of the surface of the sheet paper are exposed to laser radiation pulses to create an image in the filament from points poured by rainbow colours and visible through channels created in sheet paper by laser radiation pulses.

EFFECT: higher reliability of protection of securities from counterfeiting.

1 cl, 2 dwg

Description

The present invention relates to special types of printing and makes it possible to obtain original images inside sheet paper for protection against forgery of securities and IDs.

Prior art.

There is a known method of protection against counterfeiting securities and ID by introducing a sheet of paper inside at the stage of its manufacture of a thread (tape) and creating a protective image in it under the action of laser pulses from points formed by the interaction of laser pulses and the material of the thread (see, for example , RF patent application No. 218122225/05 D21H 21/00 21/14, B42D 25/00 25/30).

In accordance with this method, the thread introduced into the inside of the sheet paper is made in the form of a fiberglass tape made of interwoven colored glass fibers containing all the necessary components for the formation of bright colored dots of the security image under the action of laser radiation pulses, visible in transmitted light through the channels, created by pulses of laser radiation in sheet paper.

The known method makes it possible to create an easy-to-manufacture and sufficiently thin thread, which can be easily introduced inside the sheet paper during its manufacture, suitable for the manufacture of securities of any purpose with a security image of bright colored dots. However, this method does not allow protecting the security with an image of dots, iridescent colors of the rainbow when it is rotated relative to the light source, which is even more difficult to counterfeit.

There is a known method of creating a sheet material for protection against counterfeiting of securities and ID, which allows you to obtain a security image from dots iridescent with rainbow colors when it is rotated relative to the light source (see, for example, patent application RF No. 2019111021 B44F 1/08).

In accordance with this method, on opposite sides of a plastic layer transparent for laser radiation, two diffraction gratings, recessed into the plastic body, are embossed one opposite the other, these gratings are metallized and one of them is coated with a layer of metallized foil. When exposed to laser radiation pulses at specified points on the foil surface, these pulses successively interact with two diffraction gratings on both sides of the plastic layer, cause interference between them and the metallized foil layer, create points of a protective image from nanostructures iridescent in reflected light in channels in the foil body rainbow colors as you twist the plastic layer.

However, such a security image is capable of protecting a security or ID if it is aligned with them, for example, inserted into a window cut into the security or ID.

This option of using the known sheet material reduces its high security potential, since the security image will be available for manipulation with the purpose of counterfeiting. In addition, the known material provides for the operation of assembling its two parts - a film layer with two diffraction gratings and a metallized foil layer, which makes it difficult and more expensive to manufacture.

Disclosure of the invention.

The basis of the invention is the problem of obtaining such a method of protection against counterfeiting of securities and ID sheet material containing diffraction gratings, which will create a security image inside the sheet paper from dots iridescent colors of the rainbow, visible through the channels in this paper, created by pulses of laser radiation, and to simplify the manufacture of the filament to be embedded in sheet paper.

The problem is solved by the fact that in the method of protection against counterfeiting of securities and ID sheet material containing diffraction gratings, which consists in making sheet material in the form of plastic transparent for laser radiation with deposited on its opposite surfaces opposite each other and deepened into the plastic body with metallized diffraction gratings, one of which is covered with a layer of metallized foil, characterized in that the plastic transparent for laser radiation is made in the form of a thread (tape), on the opposite surfaces of which continuous metallized diffraction gratings deepened in its surface are applied opposite each other, sequentially cover the metallized diffraction grating on one of the sides of the thread with a plastic and a layer of metal that is transparent for laser radiation, then this thread is introduced into the raw paper during the production of sheet paper from it, impact on the specified points of the surface of the sheet paper with pulses laser radiation to create an image in a filament from iridescent dots, visible through channels created in sheet paper by pulses of laser radiation.

With this method of protection against counterfeiting of securities and ID sheet material containing diffraction gratings, inside the sheet paper, images inaccessible for falsification are created from dots iridescent with rainbow colors.

It is expedient that the thread is pulled between two simultaneously rotating circular toothed surfaces with the profile of the teeth and the pitch between them, corresponding to the profile of the strokes and the pitch between them of the diffraction gratings, and at the same time form by embossing on both opposite surfaces of the thread, continuous diffraction gratings deepened into them.

With this method of protection against counterfeiting of securities and ID, sheet material containing diffraction gratings provides the necessary mutual position between the strokes of diffraction gratings on both sides of the thread to obtain a high-quality security image from dots iridescent with rainbow colors.

Brief description of the drawings.

In the following, the image is explained by the description of a specific, but non-limiting embodiment of the present invention and the accompanying drawings, in which:

FIG. 1 illustrates a method of protection against counterfeiting of securities and ID with a sheet material containing diffraction gratings;

FIG. 2 illustrates the production of a filament (tape) from a plastic, transparent for laser radiation, with continuous diffraction gratings deepened into its opposite surfaces.

Best options for carrying out the invention.

The proposed method of protection against counterfeiting of securities and ID sheet material containing diffraction gratings is as follows.

A plastic transparent for laser radiation is made in the form of a thread (tape) 1, on the opposite surfaces of which continuous diffraction gratings 2 and 3 are applied, deepened into each of the surfaces of the thread 1. These diffraction gratings, recessed into the opposite surfaces of the thread 1, can, for example, be applied to a thread by embossing by pulling it between two simultaneously rotating circular toothed surfaces 4 and 5 with a tooth profile and a pitch between them corresponding to the profile of the lines and the pitch between them of diffraction gratings 2 and 3. On one of the continuous diffraction gratings 2, a layer 6 of transparent plastic is sequentially applied for laser radiation, and a layer of metal 7. Then this thread 1 is introduced into the inside of the raw paper in the process of making sheet paper 8 from it. Further, laser radiation pulses 9 are exposed to specified points on the surface of the sheet paper 8. These pulses form optical channels in the sheet paper 8 10, then they consistently interact with diffraction gratings 2 and 3, cause interference of the rays reflected from them between the diffraction gratings and the metal layer 7 and, ultimately, create pairs of volumetric nanostructures in the optical channels 10 11. When the sheet paper 8 penetrates inside through the optical channels 10 of white light, it is exposed to dispersions on areas of diffraction gratings not demetallized by a laser pulse, affect pairs of bulk nanostructures in optical channels 10 and cause them to glow in reflected light, shimmering with rainbow colors when the sheet paper is rotated relative to the light source. At the same time, this image will be black and white due to the passage of white light through demetallized areas on diffraction gratings.

Industrial applicability.

The proposed method of protection against counterfeiting of securities and ID allows you to create an image inside sheet paper from dots, iridescent colors and visible through channels in the paper, created by pulses of laser radiation. Due to this, the proposed method will dramatically improve the reliability of the protection of securities (including banknotes) and ID from counterfeiting.

Claims (2)

1. A method of protection against counterfeiting of securities with a sheet material containing diffraction gratings, which consists in making the sheet material in the form of a plastic transparent for laser radiation with metallized diffraction gratings applied to its opposite surfaces opposite each other and deepened into the plastic body, one of which is covered with a layer metallized foil, exposure to specified points of the surface of the sheet material by laser pulses, the formation of channels, the sequential interaction of these pulses with both diffraction gratings, the occurrence of laser beams interference between these gratings and the metallized foil, the creation of pairs of bulk nanostructures in the channels, the impact of transmitted light on them through the channels and subjected to dispersion on diffraction gratings, the glow of nanostructures with iridescent colors of the rainbow when the sheet material is rotated relative to the light source, characterized in that it is transparent to the laser radiation, plastic is made in the form of a thread, on the opposite surfaces of which continuous diffraction gratings deepened into its surface are applied opposite each other, these gratings are metallized, sequentially coated with a metallized diffraction grating on one of the filament surfaces with a plastic transparent for laser radiation and a metal layer, this thread is introduced inside the raw paper in the process of making sheet paper, cause the glow of pairs of bulk nanostructures in the channels when the laser beams are exposed to the filament through the surface of the sheet paper, visible through the channels in this paper. 2. The method according to claim 1, characterized in that the thread is pulled between two simultaneously rotating circular toothed surfaces with the profile of the teeth and the pitch between them, corresponding to the profile of the strokes and the pitch between them of diffraction gratings, and at the same time they form by embossing on both opposite surfaces threads deepened into them are continuous diffraction gratings.

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