WO2009074122A2

WO2009074122A2 - Protective element with identification pattern namely for protection of subjects and documents

Info

Publication number: WO2009074122A2
Application number: PCT/CZ2008/000148
Authority: WO
Inventors: Pavel Fiala; Marek Skeren; David Najdek; Jiri Perkous; Jaroslav Repta
Original assignee: All In Security S.R.O.; Ceske Vysoke Uceni Technicke V Praze
Priority date: 2007-12-13
Filing date: 2008-12-11
Publication date: 2009-06-18
Also published as: WO2009074122A3; CZ2007874A3

Abstract

The solution refers to the protective element with static identification pattern, namely for protection of subjects and documents where the identification pattern 2 remains static at turning of the protected subject along the axle 3 perpendicular to the level of protective element 1, and is characterised by a fact that each image dot (4) of observed identification pattern (2) generated by the protective element (1) is created by the original group (5) of micropoints of which at least one or more micropoints (6) of the original micropoint group (5) is contributing to the image dot (4), while at turning of the protective element (1) around the axle (3) perpendicular to the level of the protective element (1) the given image dot (4) of identification pattern (2) is created, subject to relation Δx = r Δα, by turned group (7) of micropoints, while again at least one or more micropoints of the turned group of micropoint (7) is contributing into observer's eye by the same information as one or more micropoints (6) of original group of micropoints (5) do. Some micropoints (6) are alternatively created by the micrograting diffracting the incident light into selected direction subject to grating equation (M). The protective element according to the solution is dedicated mainly to the verification of the origin of the subjects and documents by the visual checking, where the watched identification pattern remains static in its original position even under rotation of the pretected subject or document.

Description

Protective element with identification pattern namely for protection of subjects and documents

Sphere of technique

Technical solution refers to the protective element with static identification pattern, namely for protection of subjects and documents and above all it is determined against falsification and modifying and it enables a simple check by an user during which at turning of the protected subject in level of protective element the motive of protective element, for example pattern, letter or any other static marking remains while the subject is physically turned round and where the authenticity check of the subject by means of the protective pattern is moved from professional level to public one and thus helps to its mass use by common users.

Actual status of technique

In case of document protection there is a common effort to select ways trough which it is not possible to copy via classic printing techniques. For example, the protective elements, namely the types with kinetic effect with high micromotive detail rate and a way of elaboration disallowing printing, gained ground. The authenticity check of a document is made "integrally", i.e. through a simple check if the motive is identical in colour and form with model and if with kinetic type the required motive is dynamical, for example at turning of protective pattern round the axle lying in the level of protective pattern, or round the perpendicular axle to the protective pattern. The common verification of authenticity of protective patterns may basically be divided into three sections, where the first one is simple laic visual check when we can see at screen changes of colour scheme scale, kinematics, texts etc. when significant differences occur at common even colour copying. The second control and verification grade is a professional check of particular, more complicated and exacting protective patterns even through simple instruments like magnifying glasses, pocket microscopes or laser lens or similar instruments. At the third control grade, there a required laboratory and forensic control of patterns and knowledge of particular technologic aspects, localisation of protective marks and cryptographic labels is needed while for such findings strong microscopes and further instruments and equipment are needed.

Nevertheless, it shows the first grade controls, so called laic checks, remove the highest amount of imitations and that is why the focus on this section is very precious and it became purpose of this technical solution. One of realisation forms of the technical solution is based upon diffractive principle.

Principle of technical solution

The above mentioned possibility of laymen controls is solved by the protective element with static identification pattern, namely for protection of subjects and documents, where the identification pattern remains static during turning of protected subject according axle perpendicular to the level of protective element according to technical solution based on the fact, that each image dot of identification pattern generated by the protective element is formed by original group of micropoints of which at least one contributes into image dot while at turning of protective element round the axle perpendicular to the level of the protective element is the given image dot of identification pattern subject to relation Δx = r Δα formed by revolved group of micropoints whereas at least one or more of micropoints of the revolved group are the same contributing information from the original group of micropoints. Some of micropoints are alternatively formed by micrograting diffracting incident light into selected direction subject to grating equation. Some of microgratings are alternatively mutualy superimposed in one plane. Some of the micropoints are alternatively created by means of blazed grating turning of protected subject to the full angle of 360° and some micropoints are alternatively created by suitable reflexive places with inclination angle of the element perpendicular to mean angle value of illumination and observer enabling turning of structure into full angle of 360°. The image dots are alternatively located in space and at the same time the micropoints from the level of protective element of various groups of micropoints contribute to the given image dot.

Advantages of the solution subject to the technical solution lie above all in creating of an unique, easily identifiable visual effect for the observes, based on sophisticated way of image creation where each point of picture can be considered as so called image dot whose size is determined at limit between the subjective resolving power of observer similarly like at printing and it can be subject to viewing distance within the range 5 μm - 5 mm. Each image dot corresponds at given concrete turning position of the element with concrete group of micropoints forming the protective element. At illumination by white light one or more micropoints of this group spatially corresponding with the selected image dot transmit light of the given colour and intensity into the direction of observation. With static object and turning element is the given image dot displayed always by a different place of the element - different group of micropoints. And vice versa - the given point on the element creates at turning always a different place on the object. The number of micropoints corresponding with the only image dot is given by the rate of acceptable ..object breaking" for observer at turning of element. This number minimally equate to the number of differentiated angles of element turning if at defined turning more micropoints contribute to the given image dot then this number is higher. If Δα means the elementary allowed angle of turning of the protected subject and r means radius in respect of turning axle in the perpendicular level to the model, then the change of position of Δx group of micropoints corresponding to the selected image dot in perpendicular direction to the radius is given by the well-known relation:

A x = rΔ a

while the r value is variable subject to place on the object.

With respect of requirement that each group of micropoints on the element surface in size of image dot is able to transmit signal into all required discreet turnings of image towards the element, the necessary number of micropoints can be defined for the group.

For purposes of concrete realisation of system of micropoints of described qualities the diffractive gratings can be advantageously used, at defined angles of illumination and observation and thanks to dispersion they enable to select a colour of defined place on the object subject to grating equation. At light impact on regular diffractive grating with period Λ under angle θ for diffraction angle of the first diffractive order i holds the following grating equation in the form

sin θ_d = sin θ_t + -_j-

(M) where the λ means the wave length of used light.

The need to build a group of micropoints of total size of image dot with ability to transmit various information into necessary amount of directions can be in this case solved either by "crisscross" superposition of gratings within the range of the same area or by discretion into face-separated grating system when each micropoint is created by a separate single grating while the total area of such a system corresponds to the required given size in concrete case by selection of micropoint size. The particular separate microgratings differ by space frequency and orientation and modulation or elementary area according to requirement for colour, intensity and defined visual angle. Number of superimposed gratings or number of microgratings in spatially separated micropoints thus resolves the required number of point multiplication.

The grating need not to be the only possibility how to solve multiplication of the point. The micropoints contributing to particular image dots may be created by elementary mirrors variably turned towards the observer while this mirror reflection of the micropoint must generally be coloured one; this can be solved by an elementary reflexive grating or a colour spot.

The concrete selection of the realisation way is related to the selected technology. Since the dilemma of micrograting realisation is well mastered in the synthetic holography, the solution is similar to the standard production of synthetic hologram into photoresist. The production of mirror sections may be resolved in the similar way , i.e. by production into photoresist, nevertheless, the production of section is more difficult, but it may be similar to production of blazed gratings. In both of the cases the photoresist model is produced and further technological method is given by the familiar way of hologram production, for example by glavanoplastics, recombination, foil pressing etc.

Significant advantage of the selected solution subject to the invention is also in the fact, the particular image dot need not to belong to a point in level of protective element but it may be transformed for example into 3D object or two dimensional object lying in level out of the protective element and the proceeding corresponds to synthetic 3D or 2D/3D hologram with exception of aforesaid differences. Summary of pictures on drawings

The supposed technical solution will be further described by means of enclosed drawings where on fig.no. 1 the initial condition of creation of reconstruction of the protective element is displayed, which is shaped by incident light in level of the protective element and fig.no. 2 represents a sample of observation at turning of protected subject and fig. no. 3 represents image reconstruction by protective element from top view for various turning of protective element round the axle perpendicular to its level.

Example of technical solution

At fig. No. 1 the principle of creation of static reconstruction of identification pattern is displayed 2 and which shapes the incident light into defined, in space of static identification pattern 2 without respect of turning round the axle 3 perpendicular to level of protective element I₁ The protective element 1 generates identification pattern 2 in concrete example in shape of letter A in level of the protective element. Each point of observed identification pattern 2 in space is for free turning of structure in horizontal level created by contributions from at least one of micropoints 6 of the original micropoint group 5. These micropoints 6 creating given image dot 4 generally vary for different turnings.

Fig. No. 2 shows turning of the protective element 1 subject to axle 3 perpendicular to level of the protective element 1 for angle Δα , where the identification pattern 2 remains at its original position. Prior to the turning, the image dot 4 spatially corresponds with original group of micropoints 5 at surface of the protective element 1, of which one or more micropoints 6 contribute to creation of this image dot 4. After turning of the protective element 1 for angle Δα round the axle 3 remains the image dot 4 static in space, but the original group 5 of micropoints on surface of the protective elementj_. move into a different position. The image dot 4 is now spatially corresponding with generally different micropoint system, in this case with turned system 7 of micropoints on protective element 1 surface of which again at least one contributes to creation of the image dot 4.

Fig. No. 3 represents a sample of observation of reconstruction of the protective element from top view for various turning of protective element 1 round the axle perpendicular to its level gradually each time for angle of 15°. Part of the image is bound by position with the protective element and that is why it turns together with the element including letters B and a part of the image - identification pattern 2 in form of letter A is static in space and at turning of protected subject it preserves its absolute initial position.

Industrial utility

The presented technical solution can be used anywhere, where it is necessary to protect a subject, document or any other product by means of sophisticated grade of the protective element, whose authenticity it is possible to verify upon observation of simple visual effect without using any special reader. The authenticity of protective element is identifiable via simple rotation of the protective element in defined range of angles where the authentic element - identification pattern - shows itself through visual effect independently on turning angle and the observed identification pattern remains static in its original position even under rotation of structure in defined angle range.

Claims

PATENT CLAIMS

1. The protective element with static identification pattern, namely for protection of subjects and documents where the identification pattern (2) remains static at turning of the protected subject along the axle (3) perpendicular to the level of protective element (1), and is c h a r a c t e r i s e d b y a fact that each image dot (4) of observed identification pattern (2) generated by the protective element (1) is created by the original group (5) of micropoints of which at least one (6) of the original micropoint group (5) is contributing to the image dot (4), while at turning of the protective element (1) round the axle (3) perpendicular to the level of the protective element (1) the given image dot (4) of identification pattern (2) is created subject to relation Δx = r- Δα by turned group (7) of micropoints, while again at least one or more micropoints of the turned group of micropoint (7) is contributing into observer's eye by the same information as one or more micropoints (6) of original group of micropoints (5) do.

2. The protective element according to the claim 1 , is c h a r a c t e r i s e d b y the fact, that some of the micropoints (6) are atlernatively created through micrograting diffracting incident light into selected direction subject to the grating equation (M).

3. The protective element according to the claims 1 and 2, is c h a r a c t e r i s e d b y the fact, that some of microgratings are alternatively mutually superimposed one over another in one level.

4. The protective element according to the claim 1 is characterised by the fact that some of the micropoints (6) are alternatively created by the blazed grating enabling turning into full angle of 360°.

5. The protective element according to the claim 1 is characterised by the fact that some of micropoints (6) are alternatively created by suitable reflexive places with inclination angle of the element perpendicular to the mean value of illumination angle and angle of observer enabling turning of structure into the full angle of 360°.

6. The protective element subject to the claims 1 , 2, 3, 4 and 5, is characterised by the fact that image dots (4) are alternatively located generally in space and at the same time micropoints from level of the protective element (1) of various micropoint groups are contributing to the given image dot.