WO2009096813A1

WO2009096813A1 - Method for producing a diffraction grating of metal single-crystals, alloys thereof and semiconductors on a sheet material and a device for carrying out said method

Info

Publication number: WO2009096813A1
Application number: PCT/RU2008/000818
Authority: WO
Inventors: Sergei Nikolaevich Maximovsky; Grigory Avramovich Radutsky
Original assignee: Sergei Nikolaevich Maximovsky; Radutsky Grigory A
Priority date: 2008-01-29
Filing date: 2008-12-30
Publication date: 2009-08-06
Also published as: RU2008102759A; RU2389048C2

Abstract

The inventive method for producing a diffraction grating of single-crystalsof metals, alloys thereof and semiconductors on a sheet material involves impregnating a sheet material with the salt solution of a material to be crystallised and subsequently exposing said material to the action of a pulse laser radiation which forms from lines an interference pattern on the sheet material, during the pulse time, and interacts with the solution along said lines. Furthermore, a low-temperature plasma occurs at each point of the lines and forms, in the area of the existence thereof, a gas medium in which the material contained in the solution is recovered to a pure material owing to the crystallisation thereof on a liquid substrate during the plasma cooling. As a consequence of the described process, a diffraction grating is made of single-crystals of metals, alloys thereof and semiconductors along the lines of the interference pattern. The crystallisation of the material introduced into the solution will not take place beyond the lines of the interference pattern due to the short time of the laser radiation pulse (order of 10 ns), since such a short pulse excludes heat distribution beyond said lines. The period of the interference pattern lines is not in any defined interrelation with the period of the crystal lattice of the materials introduced into the solution. The device for carrying out said method makes it possible to produce a diffraction grating of single-crystals of metals, alloys thereof and semiconductors on a sheet material in a natural medium.

Description

The method of obtaining on the sheet material a diffraction grating of single crystals of metals, their alloys, semiconductors and a device for its implementation.

The present invention relates to means for special types of printing, allowing to obtain on a sheet material protective images from single crystals of various materials in the form of diffraction gratings identified in the ultraviolet, visible and infrared parts of the spectrum, as well as for the practical use of these gratings in electronics and optics.

State of the art

A known method of obtaining a protective image from single crystals of various materials on a sheet material is that a salt solution of crystallizable materials is applied to the sheet material, the sheet material is impregnated with this solution, laser pulses are applied to predetermined points of the sheet material, and single crystals of these materials are grown at these points (see RF patent JVa 2267408 class B44F 1/00).

The known method in vivo and using simple technical means, provides the application on the sheet material of the original protective image from single crystals of various materials. However, viewing this image is possible only in the light passing through the sheet material, which is not always convenient for the user. In reflected light, an image deepened in a sheet material from separate points isolated from one another is poorly distinguishable.

There is also known a method for producing single crystals of material on a crystalline substrate, which consists in placing it in a reactor chamber, filling the chamber with active gas, and the material to be crystallized is deposited from the gas phase on the substrate with a laser beam and forming a film on it. Then, using two laser beams, an interference pattern is created on this film from lines whose period is equal to the period of the crystalline lattice of the material being crystallized, and it is crystallized to form a single-crystal composition film on the substrate (see RF patent Ш 2098886 cl. BN 01L 21/268) . The application of the known method for creating a protective image on a sheet material from single crystals of various materials is difficult not only because of the severe restrictions imposed on the relationship between the periods of the interference pattern and the crystal lattice of crystallized materials. In this way, you can create a continuous film of single-crystal composition, but it is impossible to ensure the growth of single crystals of the material only along the lines of the interference pattern, which is necessary to create an original protective image. In addition, the implementation of this method requires the use of sophisticated technical equipment, a reactor chamber, through which in real printing production it is almost impossible to pass sheet material and perform the operations described above, including forming interference patterns on the sheet material through the chamber-reactor windows .

Disclosure of invention

The basis of the invention is the creation of such methods for producing on a sheet material a diffraction grating of single crystals of metals, their alloys and semiconductors and a device for its implementation, which would allow creating an original protective image that cannot be reproduced in any other way on a sheet material.

The problem is solved in that, in a method for producing a diffraction grating on a sheet material from single crystals of metals, their alloys and semiconductors, which consists in the fact that a salt solution of crystallizable materials is applied to the sheet material, impregnated with the sheet material with this solution, and the set points of the sheet material are exposed by laser pulses and single crystals of these materials are grown at the indicated points, in accordance with the invention, an interference pattern is created on the sheet material from lines whose period does not depend on the periods of the crystal lattices of crystallized materials, single crystals of materials are grown along these lines and form a diffraction lattice from their totality.

With this method of producing a diffraction grating on a sheet material, the possibility of crystallization of materials outside interference lines and provides the creation of a diffraction grating of single crystals of materials during the duration of a laser pulse interacting along the interference lines with a solution of salts of crystallized materials.

It is advisable that on the sheet material set the period of the lines of the interference pattern in the ranges of 0.2 μm - O, 3 μm; 0.4 μm - 0.7 μm; 0.7 μm - l, 0 μm and form diffraction gratings, respectively, for the ultraviolet, visible and infrared parts of the spectrum.

With this method of obtaining a diffraction grating on a sheet material, it is possible to create a complex of protective images on it.

It is advisable that they form recesses in the sheet material along the interference pattern lines and single crystals of materials are grown in these recesses.

With this method of obtaining a diffraction grating on a sheet material, its durability is ensured due to abrasion protection.

The problem is also solved by the fact that in a device for producing a diffraction grating on a sheet material from single crystals of metals, their alloys and semiconductors, comprising a means for applying a salt solution of crystallizable materials to a sheet material and a means for separating materials from a solution and crystallization in accordance with the invention , the means for separating from solution and crystallization of materials is made in the form of a generator of two laser beams, the interaction of which with each other causes the creation of a sheet The material of the interference pattern consists of lines with a period that is independent of the periods of the crystal lattices of crystallized materials, and the interaction of the rays with the sheet material along the lines of the interference pattern causes the growth of single crystals of materials from these lines from a solution of their salts.

With this embodiment of the device, during the duration of the pulse duration of the interacting laser beams, the creation of a diffraction grating made of single crystals of metals, their alloys and semiconductors on a sheet material located in the natural environment ensures the creation of a new protective image on the sheet material that is not reproducible by any other device. Brief Description of the Drawings

The invention is further illustrated by the description of specific, but not limiting, embodiments of the invention and the accompanying drawings, in which:

Figure l illustrates the proposed method for producing a diffraction grating on a sheet material;

Figure 2 illustrates a General view of a device for producing a diffraction grating on a sheet material.

The best embodiments of the invention

The proposed method for producing on a sheet material a diffraction grating of single crystals of metals, their alloys and semiconductors is as follows.

A solution B containing salts of one or more metals or salts of semiconductors is applied to sheet material A (FIG. 1). They impregnate sheet material A with this solution and direct the laser beams D and E, interacting with each other in such a way that an interference pattern appears on the sheet material. C. This picture consists, for example, of parallel lines with a period that is not in any definite relationship with the period of the crystal lattices of materials in solution and to be crystallized. The pulsed action on the sheet material of interacting laser beams D and E occurs along the lines F of the interference pattern. During the duration of the pulse along the lines of the interference pattern, the laser radiation interacts with the solution with which the sheet material is impregnated.

In this case, at each point of these lines, a low-temperature plasma arises, creating a gaseous medium in the region of its existence, in which the material introduced into the solution is restored to pure material as a result of its crystallization on the liquid substrate as the plasma cools.

As a consequence of the described process, a diffraction grating G is formed from the lines of the interference pattern F from single crystals of metals, their alloys and semiconductors. With sufficient laser pulse power, the described the process will be combined with the process of burning the surface layer of the sheet material along the lines of the interference pattern, as a result of which single crystals of metals, their alloys and semiconductors will grow in depressions formed along these lines. The crystallization of the materials introduced into the solution will not occur outside the lines of the interference pattern due to the short laser pulse duration (of the order of 10 ns), because with such a short pulse, heat propagation beyond these lines is excluded.

The proposed device for producing on a sheet material a diffraction grating of single crystals of metals, their alloys and semiconductors contains means 1 for applying a salt solution of crystallizable materials to a sheet material 2 and a means 3 for separating these materials from a solution and crystallization.

The means 1 for applying to the sheet material 2 a salt solution of crystallizable materials contains a container 4 with a solution and a device 5 for impregnating sheet material 2 with this solution, including a number of driving (not shown) rollers 6 for transferring the solution from the container to the sheet material.

The means 3 for separation from the solution and crystallization of materials contains a generator 7 of two laser beams 8 and 9, directed with the possibility of interaction between each other and the optical system 1 O ^ transferring the result of this interaction in the form of interference pattern 11 to the sheet material 2.

In this case, the period of the interference pattern lines is not in any definite relationship with the period of the crystal lattices of materials in solution and subject to crystallization.

Sheet material 2 moves along the technological positions of its processing by the conveyor 12.

The proposed device for producing on a sheet material a diffraction grating of single crystals of metals, their alloys and semiconductors works as follows.

When the sheet material 2 is moving on the conveyor 12, a solution containing either salts of one or more metals or salts of semiconductors is applied to it with rollers 6. Then, the sheet material 2 is moved to the position of formation of a diffraction grating on it. At this position, as a result of the pulsed interaction between the laser beams 8 and 9 of the generator 7, directed through the optical system 10 to the sheet material 2, an interference pattern 11 appears on its predetermined section, along the lines of which the laser beam interacts with the solution that has saturated this material.

As a result of this interaction, during the duration of the laser pulse (of the order of 10 ns) along the lines of the interference pattern 11, the material introduced into the solution is restored to pure material as a result of its crystallization on the liquid substrate, and the totality of single crystals grown along these lines forms a diffraction grating 13 .

Industrial applicability

The method of producing a diffraction grating on a sheet of metal from single crystals of metals, their alloys, semiconductors and a device for its implementation allow you to create reliable protection against counterfeiting on the sheet material (banknote), identified in the ultraviolet, visible and infrared parts of the spectrum.

When turning a sheet of material with a diffraction grating deposited on it for the visible part of the spectrum, the light reflected from the grating will shimmer from purple to red and vice versa.

The proposed method and device for its implementation can also be used in electronics and optics for the manufacture of sheet diffraction gratings.

Claims

Claim

1. The method of obtaining on a sheet material a diffraction grating of single crystals of metals, their alloys and semiconductors, which consists in applying a salt solution of crystallizable materials to a sheet material, impregnating the sheet material with this solution, affecting predetermined points of the sheet material with laser pulses and growing single crystals of these materials at the indicated points, characterized in that an interference pattern of lines is created on the sheet material, the period of which does not depend on the periods of crystalline lattices of crystallized materials, single crystals of materials are grown along these lines and form a diffraction lattice from their totality.

2. The method according to claim 1, characterized in that the period of the interference pattern lines in the ranges 0.2μkm-0, Zμkm is set on the sheet material; 0.4 μkm-0.7μkm; 0.7μkm-l, 0μkm and form diffraction gratings, respectively, for the ultraviolet, visible and infrared parts of the spectrum.

3. The method according to p. 1, characterized in that they form recesses in the sheet material along the interference pattern lines and single crystals of materials are grown in these recesses.

4. A device for producing on a sheet material a diffraction grating of single crystals of metals, their alloys and semiconductors, comprising a means for applying a salt solution of crystallizable materials to the sheet material and a means for separating materials from the solution and crystallizing, characterized in that the means for separating from the solution and crystallization of materials is made in the form of a generator of two laser beams, the interaction of which with each other causes the creation on the sheet material of an interference pattern of lines with Heat-not dependent on the period of the crystal lattices of the crystallizable material, and reacting rays sheeting along lines cause interference pattern of these lines growing single crystals of materials from a solution of their salts.