Secure item comprising a revealing screen and a combined image

Abstract

A secure item including a revealing screen and a combined image, or an assembly comprising a secure item and another object. The secure item including one of the revealing screen and the combined image, and the object including or forming the other one of the revealing screen and the combined image. The combined image being made up of a plurality of interlaced images each interlaced image and/or the revealing screen being made up of a plurality of elements. The revealing screen making it possible, when placed on top of the combined image, to observe various revealed images by moving the revealing screen relative to the combined image and/or by changing the observation angle, the revealed images each including a certain proportion of each interlaced image, and the elements being made up of one or more micro-patterns.

Claims

1. A secure item comprising a revealing raster and a combined image, the combined image being composed of a plurality of interlaced images, each interlaced image and the revealing raster being composed of a plurality of elements, the revealing raster making it possible, when it is superposed with the combined image, to observe different revealed images by displacing the revealing raster with respect to the combined image and/or by changing an angle of observation a, the revealed images each comprising a certain proportion of each interlaced image, and the elements being composed of one or more micropatterns, the micropatterns belonging to different interlaced images being different through their colors, hues, opacities, saturations or luminescences or brightnesses.

2. The item as claimed in claim 1, all the elements of all the interlaced images and/or of the revealing raster being composed of one or more micropatterns.

3. The item as claimed in claim 1, the elements of the interlaced images and/or of the revealing raster each being composed of several micropatterns.

4. The item as claimed in claim 1, the micropatterns exhibiting at least one dimension of less than or equal to 1 mm.

5. The item as claimed in claim 1, the micropatterns belonging to different interlaced images being different through their aspects and exhibiting a contrast and/or a sufficient colorimetric difference to make it possible to distinguish two adjacent interlaced-image elements when they are observed with a certain enlargement.

6. The item as claimed in claim 5, the micropatterns belonging to different interlaced images being of different shapes and/or of different colors.

7. The item as claimed in claim 1, the combined image exhibiting a resolution of greater than or equal to 800 dpi.

8. The item as claimed in claim 1, the elements of a same interlaced image appearing of a same color but of a different color from those of the other interlaced images.

9. The item as claimed in claim 1, the interlaced image comprising a periodic alternation of elements of interlaced images in one or more direction, each revealed image corresponding to an interlaced image.

10. The item as claimed in claim 1, the interlaced image comprising a periodic alternation of elements of interlaced images in one or more direction, each revealed image corresponding to an interlaced image, the item being disposed in such a way that when the revealing raster and the combined image are superposed, the directions in which the raster elements alternate periodically and the directions in which the interlaced-image elements alternate periodically are identical.

11. The item as claimed in claim 1, being disposed in such a way that the revealed images are observable in reflected light and/or in transmitted light.

12. The item as claimed in claim 1, being disposed in such a way that the revealed images are observable at one and the same time on the side of the revealing raster and on the side of the combined image.

13. The item as claimed in claim 1, the revealed images forming macropatterns exhibiting different aspects.

14. The item as claimed in claim 1, one at least of the combined image and of the revealing raster featuring on a region of the secure item, a superposition of the revealing raster and of the combined image being performed by folding of the security document, the revealing raster making it possible, when superposed at least partially with the combined image of the secure item, to observe different revealed images through a relative displacement of the revealing raster with respect to the combined image in a or one of directions of the combined image and of the revealing raster.

15. The item as claimed in claim 1, the revealing raster and the combined image being superposed by being separated from one another by a gap of constant thickness.

16. The item as claimed in claim 15, being disposed in such a way that the revealing raster makes it possible to observe different revealed images upon a change of the direction a observation of the secure item.

17. A method for authenticating a secure item according to claim 1, in which the revealed image is observed through the revealing raster, the angle of observation and/or the position of the revealing raster are/is changed with respect to the combined image so as to observe a change of the revealed image and it is concluded as regards an authenticity of the security item in view of an observed change of image.

18. An assembly comprising a secure item and another object, the secure item comprising one of the revealing raster and of the combined image and the object comprising or forming the other of the revealing raster and of the combined image, the combined image being composed of a plurality of interlaced images, each interlaced image and/or the revealing raster being composed of a plurality of elements, the revealing raster making it possible, when it is superposed with the combined image, to observe different revealed images by displacing the revealing raster with respect to the combined image and/or by changing an angle of observation a, the revealed images each comprising a certain proportion of each interlaced image, and the elements being composed of one or more micropatterns, the micropatterns belonging to different interlaced images being different through their colors, hues, opacities, saturations or luminescences or brightnesses.

19. The assembly as claimed in claim 18, the other object being an electronic imager making it possible to form a first image, the first image being the revealing raster or the combined image, so as to be able to superpose it with a second image of the secure item, the second image being the other of the revealing raster and of the combined image.

20. The item as claimed in claim 18, one at least of the combined image and of the revealing raster featuring on a region of the at least partially transparent object, the superposition of the revealing raster and of the combined image being performed by a superposition of the security document with the other object, the revealing raster making it possible, when superposed at least partially with the combined image of the secure item or of the other object, to observe different revealed images through a relative displacement of the revealing raster with respect to the combined image in the or one of the directions of the combined image and of the revealing raster.

Description

(1) The invention will be able to be better understood on reading the detailed description which will follow, of nonlimiting exemplary implementations of the latter, and on examining the appended drawing in which:

(2) FIG. 1A illustrates the formation of a combined image,

(3) FIG. 1B is an enlarged detail of FIG. 1A,

(4) FIGS. 2A to 2C represent a succession of revealed images such as it may be observed when the observation conditions vary,

(5) FIGS. 3A to 3C represent a variant succession of revealed images such as it nay be observed when the observation conditions vary,

(6) FIG. 4 illustrates a variant combined image,

(7) FIGS. 5A to 5D represent a succession of revealed images such as they may be observed with the aid of the combined image of FIG. 4, when the observation conditions vary,

(8) FIG. 6 illustrates a variant combined image,

(9) FIGS. 7A to 7H represent variants of revealing rasters,

(10) FIG. 8 represents in cross-section, in a schematic and partial manner, an exemplary secure item produced in accordance with an exemplary implementation of the invention.

(11) FIG. 9 illustrates the possibility of varying the inclination by deforming the secure item,

(12) FIGS. 10 and 11 represent two examples of secure items according to the invention,

(13) FIGS. 12A to 12D represent other examples of secure items according to the invention, in transverse section, in a schematic manner,

(14) FIGS. 13 and 14 illustrate variant embodiments of secure items according to the invention, in transverse section, in a schematic manner,

(15) FIGS. 15 and 16 represent exemplary embodiments of the secure item according to the invention, the combined image or the revealing raster being carried by a window of the item.

(16) FIG. 17 represents the secure item folded,

(17) FIGS. 18 and 19 represent exemplary embodiments of secure item according to the invention, the combined image or the revealing raster being carried by a security thread,

(18) FIGS. 20 to 23 represent other exemplary embodiments of secure items according to the invention, the combined image and/or the revealing raster being carried by at least one security thread or a foil.

(19) FIGS. 24 to 26 represent variant assemblies comprising an electronic imager and an item,

(20) FIG. 27 represents a variant of first images formed by an electronic imager,

(21) FIG. 28 represents a variant item comprising an integrated microcircuit, and

(22) FIG. 29 represents a variant assembly, the item comprising a second image in the form of a revealing raster and the electronic imager producing a first image in the form of a combined image,

(23) FIG. 30A represents another exemplary combined image,

(24) FIG. 30B represents a variant with a revealing raster in the form of pixels, and

(25) FIGS. 30C to 30E represent a succession of revealed images such as it may be observed with the aid of the combined image of FIG. 30A and revealing rasters of FIG. 30B when the observation angle varies and/or the relative position of the revealing raster and of the combined image varies.

COMBINED IMAGE

(26) Illustrated in FIG. 1 is an example of forming a combined image I by adding together a plurality of interlaced images I.sub.1, I.sub.2, . . . , I.sub.n. Each interlaced image I.sub.i is formed of interlaced image lines i.sub.i arranged in a periodic manner in the direction X.sub.1 and of like width I.sub.i constant over their entire length. The interlaced images are of like period S.

(27) As illustrated in FIG. 1B representing a detail of the combined image, the lines of the interlaced images i.sub.1 to i.sub.n comprise micropatterns 7 such as illustrated in FIG. 1B, in particular are formed by micropatterns 7. The micropatterns 7 of the lines i.sub.i of an interlaced image I.sub.i may be identical.

(28) Preferably, the micropatterns 7 of the lines i.sub.1 to i.sub.n belonging to different interlaced images are of different aspects, especially of different shapes and/or of different hues, opacities, luminescences, brightnesses and/or saturations. Preferably, the micropatterns 7 of the lines i.sub.1 to i.sub.n belonging to different interlaced images are of different shapes, for example represent different alphanumeric signs and/or are of different hues, opacity, saturation, luminescences or brightnesses, for example of different colors.

(29) Preferably, the micropatterns 7 are of the width l of the lines i.sub.i of the interlaced image and of a height of the same order of magnitude so that, in view of the resolution, the lines i.sub.i appear of a homogeneous color, the micropatterns 7 not being distinguishable to the eye. The user must for example use a magnifying glass to view the micropatterns 7, thereby strengthening the security of the item.

(30) For example, the micropatterns 7 of the lines i.sub.i of an interlaced image may be of a certain hue so that the lines it appear colored in a homogeneous manner.

(31) The micropatterns 7 may be in positive or in negative.

(32) The micropatterns may represent alphanumeric signs, digits, text, geometric shapes, objects, people or animals.

(33) Such micropatterns 7 make it possible to strengthen the security of the item 10 since they form additional security elements hidden in the lines which are not visible to the naked eye. Moreover, the lines are more difficult to counterfeit since they require a high resolution during manufacture, especially during printing.

(34) In the example illustrated in FIG. 1B, the combined image I is formed of three interlaced images I.sub.1, I.sub.2 and I.sub.3 each comprising interlaced-image lines i.sub.1, i.sub.2 or i.sub.3 exhibiting colored micropatterns 7. The lines i.sub.1 of the first interlaced image I.sub.1 are formed of a repetition of the number 100 in positive writing colored red, the lines i.sub.2 of the second interlaced image I.sub.2 are formed of a repetition of the word AWS in positive writing colored green and the lines i.sub.3 of the third interlaced image I.sub.3 are formed of a repetition of the word BUTTERFLY in positive writing colored blue. To the naked eye, the lines i.sub.1 appear red, the lines i.sub.2 appear green and the lines i.sub.3 appear blue, the micropatterns 100, AWS and BUTTERFLY not being visible.

(35) Hereinafter in the figures, the micropatterns 7 of the lines i.sub.1 to i.sub.n are no longer represented. The lines i.sub.1 to i.sub.n are represented as lines of homogeneous aspect but it must be understood that they exhibit micropatterns 7 such as described hereinabove.

(36) The interlaced image lines i.sub.i have parallel longitudinal axes defining a general orientation O.sub.i of the image combined by their general direction. The periodicity is observed along an axis X.sub.1 perpendicular to the longitudinal axis of the interlaced image lines.

(37) The combined image I corresponds to the superposition of these interlaced images I.sub.1 to I.sub.n while shifting them with respect to one another along the axis X.sub.1 so that the interlaced image lines i.sub.1 to i.sub.n are not superposed between the various images.

(38) The widths l.sub.1 to l.sub.n of the lines of the interlaced images i.sub.1 to i.sub.n are such that the sum of the widths l.sub.1 to l.sub.n of these lines i.sub.1 to i.sub.n is less than or equal to the period S, and preferably, equal to the period S:

(39) $\underset{j=1}{\overset{n}{.Math.}}\mathrm{lj}=S$

(40) In the example illustrated, the lines of an interlaced image i.sub.1 to i.sub.3 are of like width l.sub.1 to l.sub.3 equal to S/3.

(41) As a variant, the lines i.sub.1 to i.sub.n of the interlaced images may be of widths l.sub.1 to l.sub.n that differ with respect to one another, such as represented in FIG. 8A.

(42) In the example of FIG. 1, the combined image I is formed of three interlaced images I.sub.1 to I.sub.3. The first interlaced image I.sub.1 is formed of a periodic red line i.sub.1, the second interlaced image I.sub.2 is formed of a periodic green line i.sub.2 and the third interlaced image I.sub.3 is formed of a periodic blue line i.sub.3. The three lines of the interlaced images i.sub.1 to i.sub.3 are of like width l. The lines of the interlaced images i.sub.1 to i.sub.3 are rectilinear. The resulting combined image I is a rasterized image exhibiting a periodic alternation of lines i.sub.1 to i.sub.3 of various colors.

(43) The period S is between 10 m and 1 mm, preferably between 50 and 200 m.

(44) The width l of the lines of the interlaced images i.sub.1 to i.sub.n is less than or equal to 50 m, being for example substantially equal to 33 m. This value corresponds to a resolution of the combined image I of about 800 dpi, this representing a limit for conventional printers which generally have a maximum definition of 600 dpi, and which constitutes a security factor.

(45) Moreover, the human eye not perceiving, at an observation distance of greater than or equal to 30 cm, details of less than approximately 100 m, a sufficiently fine combined image appears of homogeneous aspect, for example substantially white here in transmitted light.

(46) Hence, whatever the color or colors used for the combined image, the printing definition may be precise enough for the mixture of the colors to appear as homogeneous.

(47) Revealing Raster

(48) In the example illustrated in FIGS. 2A to 3C, the revealing raster 4 is composed of a periodic alternation of constant period Q of straight and occulting raster lines 5a, especially of black opaque lines, and of non-occulting lines 5b, especially of transparent lines having parallel longitudinal axes. The periodicity is observed along an axis X.sub.T perpendicular to the longitudinal axis of the raster lines 5a and 5b.

(49) The longitudinal axes of the raster lines 5a and 5b define a general orientation of the raster O.sub.t by their general direction.

(50) The opaque raster lines 5a are of a constant width m which is less than the period Q of the raster and the transparent raster lines 5b are of a constant width k which is less than the period Q.

(51) The widths of the opaque raster lines 5a and of the transparent raster lines 5b may or may not be identical.

(52) In the example illustrated, the raster lines 5a and 5b have rectilinear and parallel edges, but it may be otherwise. The revealing raster 4 may comprise other patterns such as crenellations or undulations, such as is illustrated respectively in FIGS. 7A and 7B.

(53) The resolution of the revealing raster 4 is, preferably, greater than or equal to 800 dpi.

(54) The revealing raster 4 may be as such of homogeneous aspect to the naked eye and at a normal observation distance, having regard to its fineness. In particular, the revealing raster may appear to the naked eye at 15 cm distance as having a uniform, gray color, which is darker or lighter according to the width in of the opaque raster line 5a.

(55) A sufficiently fine combined image and a sufficiently fine revealing raster make it possible to afford anti-photocopy security.

(56) The combined image I and/or the revealing raster 4 may be formed by printing, metallization, demetallization, laser marking, lithography or any other technique making it possible to fix or unveil an image.

(57) To improve security, it is possible to use liquid-crystal inks, for example to print the combined image I. Animation, in order to be revealed, may then require in addition to the revealing raster, the use of a polarizer filter, which may or may not be present on the item.

(58) The revealing raster 4 may be formed by printing or metallization and/or demetallization.

(59) The opaque raster lines 5a of the revealing raster 4 may be glossy or matt.

(60) As a variant, not illustrated, the opaque lines of the revealing raster may comprise micropatterns such as those described in conjunction with FIG. 1B.

(61) As a variant, the revealing raster 4 is different, especially the raster lines are not opaque and transparent. The occulting raster lines may be formed of a filter not allowing the wavelengths corresponding to the combined image to pass through and the non-occulting raster lines may allow these wavelengths to pass through at least partially.

(62) Revealed Image

(63) The period Q of the revealing raster 4 is equal to the period S of the combined image I.

(64) When the revealing raster 4 and the combined image I are superposed and the general orientation O.sub.t of the revealing raster 4 is substantially the same as the general orientation O.sub.i of the combined image I, a revealed image I.sub.r may be observed. The revealed image I.sub.r then corresponds to the parts of the combined image I that are present under the transparent raster lines 5b for a given angle of observation.

(65) Indeed, when the revealing raster 4 and the combined image I are superposed, under the condition cited previously and when the revealed images are observed on the revealing raster side, the opaque raster lines 5a mask one part of the interlaced image lines i.sub.1 to i.sub.n, the other part of the interlaced image lines i.sub.1 to i.sub.n being visible through the transparent raster lines 5b. The transparent raster lines 5b all allow the viewing of the same proportion (P.sub.1; . . . ; P.sub.n) of the interlaced image lines i.sub.1 to i.sub.n. The proportion P.sub.i corresponds to the proportion of a line i.sub.i of the interlaced image I.sub.i that is visible.

(66) In the case where the superposition is observed on the combined image I side, the opaque raster lines 5a render the interlaced image lines i.sub.1 to i.sub.n on which they are superposed dark and therefore prevent them being viewed. Thus only the interlaced image lines i.sub.1 to i.sub.n superposed on the transparent raster lines 4h are visible to form the revealed image I.sub.r.

(67) Preferably, the revealed images I.sub.r are observable in reflected light and in transmitted light.

(68) Colored Image

(69) In the example of FIGS. 2A to 2C, the interlaced image lines i.sub.1 to i.sub.n are all of the same width I.sub.1 to I.sub.n and the opaque raster lines 5a have a width m equal to twice the width of the interlaced image lines i.sub.1 to i.sub.n. Thus, the opaque raster lines 5a, when they are properly positioned with respect to the interlaced image lines i.sub.1 to i.sub.n, cover two interlaced images, i.e. two colors, and only one interlaced image, i.e. a single color, is visible. In the case of FIG. 2A, all of the blue is visible and all of the red and the green are hidden, the proportion (P.sub.1; . . . ; P.sub.n) of the interlaced image lines to in of the revealed image I.sub.r is (0; 0; 1). Likewise for FIG. 2B, the proportion (P.sub.1; . . . ; P.sub.n) of the interlaced image lines i.sub.1 to i.sub.n of the revealed image I.sub.r is (1; 0; 0) and for FIG. 2C, the proportion (P.sub.1; . . . ; P.sub.n) of the interlaced image lines i.sub.1 to i.sub.n of the revealed image I.sub.r is (0; 1; 0).

(70) As a variant, in the example of FIGS. 3A to 3C, the interlaced image lines i.sub.1 to i.sub.n are all of the same width I.sub.1 to I.sub.n and the opaque raster lines 5a have a width in equal to 0.75 times the width of the interlaced image lines i.sub.1 to i.sub.n. Thus, the opaque raster lines 5a, when they are properly positioned with respect to the interlaced image lines i.sub.1 to i.sub.n, cover three-quarters of one of the interlaced images, i.e. three-quarters of a color; two interlaced images and a quarter of the third interlaced image are therefore visible. In the case of FIG. 3A, all of the blue and the green and a quarter of the red are visible and three-quarters of the red is hidden, the proportion (P.sub.1; P.sub.2; P.sub.3) of the interlaced image lines i.sub.1, i.sub.2 and i.sub.3 of the revealed image I.sub.r is (0.25; 1; 1). Likewise for FIG. 3B, the proportion (P.sub.1; P.sub.2; P.sub.3) of the interlaced image lines i.sub.1, i.sub.2 and i.sub.3 of the revealed image I.sub.t is (1; 0.25; 1) and for FIG. 3C, the proportion (P.sub.1; P.sub.2; P.sub.3) of the interlaced image lines i.sub.1, i.sub.2 and i.sub.3 of the revealed image I.sub.r is (1; 1; 0.25).

(71) The revealed image I.sub.r may appear homogeneous to the naked eye. In the case of a combined image I in the form of a colored raster formed of an alternation of red, green and blue lines of identical widths l and of a revealing raster of width of a transparent raster line k, it is possible to determine the color of the revealed image I.sub.r in RGB coordinates on the basis of the proportion (P.sub.R, P.sub.G, P.sub.B). The RGB coordinates take the form of three numbers lying between 0 and 255 characterizing said color, each number representing the proportion of one of the components red, green and blue making it possible to obtain said color.

(72) The components have coordinates:
R=R.sub.max*P.sub.R,
G=G.sub.max*P.sub.G, and
B=B.sub.max*P.sub.B,
with R.sub.max=G.sub.max=B.sub.max=255*k/S

(73) It is thus possible to determine the color of the image revealed as a function of the width k of the transparent raster lines 5b and of the proportion (P.sub.R, P.sub.G, P.sub.B) of the interlaced images I.sub.1, I.sub.2 and I.sub.3.

(74) The revealed image Ir is observable in transmitted light or in reflected light at one and the same time on the revealing raster 4 side and on the combined image I side when the revealing raster 4 and the combined image I are superposed.

(75) Image Revealed in Pattern Form

(76) In the variant, illustrated in FIGS. 4 to 5D, each interlaced image I.sub.1 to I.sub.n comprises a periodic alternation of continuous or discontinuous lines such as are described previously, forming a pattern, for example such as represented in FIG. 4. The pattern may represent a text, alphanumeric signs, ideograms, an object, a person, a plant, a monument and/or an animal. The transparent raster lines 5b are of width k equal to the width l of a line of interlaced images. Thus, the revealed image corresponds to one of the interlaced images and may allow, as illustrated in FIGS. 5A to 5D, the observation of at least one pattern of the revealed interlaced image. A change of the conditions of observations corresponding to a relative displacement of the revealing raster 4 with respect to the combined image I along the axis X and/or a change of the angle of observation of the revealing raster 4 and of the combined image I may make it possible to successively observe the various interlaced images I.sub.1 to I.sub.n, and this may make it possible to give an effect of motion when the interlaced images I.sub.1 to I.sub.n, each represent the decomposition of a motion.

(77) In the example of FIGS. 4 to 5D, the combined image I comprises four interlaced images I.sub.1, I.sub.2, I.sub.3 and I.sub.4 representing various positions of a rotating spiral, such as are represented in FIG. 4. The interlaced-image lines i.sub.1, i.sub.2, i.sub.3 and i.sub.4 are discontinuous. The revealing raster 4 allows, when it is superposed with the combined image while having the same orientation, the observation of the spiral of one of the interlaced images I.sub.1 to I.sub.4, as is illustrated in FIG. 5A.

(78) In the variant illustrated in FIG. 30A, the combined image I comprises a periodic alternation of interlaced-image pixels p.sub.1 to p.sub.n in two directions X and Y. The interlaced-image pixels p.sub.1 to p.sub.n are of rectangular shape but it could be otherwise. For example the pixels could be of another polygonal shape, especially square, triangle, hexagon or lozenge.

(79) The pixels of FIG. 30A may also be seen as diagonal interlaced image lines formed of pixels joined together by one of their corners alternating periodically in the direction Z.

(80) The preceding description, given for lines, applies to the pixels. Thus, the pixels p.sub.1 to p.sub.n belonging to different interlaced images exhibit a different aspect, especially a different hue, saturation, glossiness, transparency, luminescence. For example the pixels p.sub.1 to p.sub.n belonging to different interlaced images are of different colors, especially red, green and blue.

(81) The combined image I exhibits a period S.sub.X in the direction X.sub.I and a period S.sub.Y in the direction Y.sub.I. Here, the directions X.sub.I and Y.sub.I are perpendicular but it could be otherwise. The directions X.sub.I and Y.sub.I could form a non-zero angle, different from 90, between themselves.

(82) The interlaced-image pixels p.sub.1 to p.sub.n exhibit a dimension l.sub.X and a dimension l.sub.Y in respectively the directions X.sub.I and Y.sub.I. The dimensions l.sub.X and l.sub.Y are each such as described previously for the interlaced image lines i.sub.1 to i.sub.n.

(83) The revealing raster 4 is according to FIG. 30B. It exhibits a periodic alternation of opaque raster pixels 5a in two directions X.sub.T and Y.sub.T forming between themselves the same angle as the directions X.sub.I and Y.sub.I. The opaque raster pixels 5a are separated from one another by transparent gaps 5b and repeat according to the periods S.sub.X and S.sub.Y of the combined image in the respective directions X.sub.T and Y.sub.T.

(84) The pixels of the revealing raster may be of a dimension m.sub.X and of a dimension my in the respective directions X.sub.T and Y.sub.T which are less than the periods S.sub.X and S.sub.Y respectively.

(85) In the example illustrated, the dimension m.sub.X in the direction X.sub.T is equal to the dimension l.sub.X of the interlaced-image pixels p.sub.1 to p.sub.n and the dimension m.sub.Y in the direction Y.sub.T is equal to the dimension l.sub.Y of the interlaced-image pixels p.sub.1 to p.sub.n.

(86) The dimensions m.sub.X and m.sub.Y may be different respectively from l.sub.X and l.sub.Y on condition that the periods of the revealing raster 4 and of the combined image I are the same in each of the directions X and Y.

(87) Upon superposing the revealing raster 4 and the combined image I so that the directions X.sub.T and X.sub.I coincide and that the directions Y.sub.T and Y.sub.I coincide, the revealing raster makes it possible to observe revealed images I.sub.r such as are represented in FIGS. 30C to 30E.

(88) In the example illustrated the opaque raster pixels 5a hide one of the interlaced images I.sub.1 to I.sub.n so that two of the interlaced images are visible. In FIG. 30C, the revealed image I.sub.r is formed of the green and red interlaced images, in FIG. 30D, the revealed image I.sub.r is formed of the blue and red interlaced images and in FIG. 30E, the revealed image I.sub.r is formed of the blue and green interlaced images.

(89) The various revealed images I.sub.r illustrated may be obtained by displacing the revealing raster 4 with respect to the combined image in the direction X.sub.I, the direction Y.sub.I or the direction Z and/or by changing the angle of view around the directions X.sub.I, Y.sub.I or Z.

(90) Observation of a Change of the Revealed Image

(91) It is possible to vary the revealed image I.sub.r observed by changing the conditions of observation of the superposed revealing raster 4 and combined image I, and especially, as is detailed hereinafter, by changing the angle of observation and/or by displacing the revealing raster 4 with respect to the combined image I. Thus, virtually or really, by displacing the combined image I with respect to the revealing raster 4 in the direction X of alternation of the raster lines and of the combined-image lines, the revealed image I.sub.r varies.

(92) By changing the observation conditions, it is possible to pass from FIG. 2A to FIG. 2B and to FIG. 2C. The same holds for FIGS. 3A to 3C and FIGS. 5A to 5D.

(93) By varying the observation conditions, the user may then see a change of the revealed image I.sub.r and conclude in view of this observation as to the authenticity of the item.

(94) In the case where the interlaced images are such as described in conjunction with FIGS. 4 to 5D, the displacement of the revealing raster 4 with respect to the combined image I along the axis X allows the observation successively of the various interlaced images I.sub.1 to I.sub.4, thereby giving the user the impression that the spiral is rotating about its central axis.

(95) Observation by Superposition on Either Side of a Support

(96) Represented in FIG. 8 is a first embodiment in which a secure item 10 according to the invention comprises a non-opaque, for example perfectly transparent, substrate 20 having a first face 20a carrying the combined image I. The second face 20b of the substrate 2, opposite to the first face, carries the revealing raster 4.

(97) When the secure item 10 is observed from one side or from the other of the substrate, the revealing raster 4 makes it possible to observe one or more revealed images I.sub.r. By changing the angle of observation a, the user changes the observation conditions and the revealed image or images I.sub.r are modified as described previously. For the eye, a change of the angle of observation corresponds to a relative displacement of the revealing raster 4 with respect to the combined image I.

(98) To be able to view all the interlaced images up to an angle of inclination of about 45, the thickness e of the substrate is, preferably, greater than or equal to approximately the period Q.

(99) For example, if a raster of 100-m period Q is used, the thickness e of the substrate is greater than 100 m.

(100) It may be advantageous to have a substrate whose thickness e is less than or equal to 30 m, better 25 m, for example lying between 20 and 30 m, or indeed 20 and 25 m, bounds included or excluded.

(101) Another possibility for varying the direction of observation of the secure item may be to deform the substrate, for example around a fold axis, as illustrated in FIG. 9.

(102) As the optical system may operate in transmitted or reflected light, it may be used for windows or threads introduced as windows, for example into a banknote.

(103) As a function of the pattern of the revealing raster 4, a tagging of the latter with respect to the combined image I may be necessary, especially in the sense parallel to their general orientation. For example, for a linear revealing raster such as illustrated in FIG. 2, no tagging is necessary; on the other hand, for an undulated raster, a more or less precise tagging, as a function of the amplitude and of the frequency of the undulations, may turn out to be desirable. The invention thus offers a possibility of securing that can be modulated as a function of the protection sought and of the difficulty of implementation.

(104) For secure items comprising a thread introduced as window(s), the combined image I may be obtained by micro-photolithography of the thread and the revealing raster 4 may be produced with the help of offset printing with inks crosslinking under UV, performed subsequently when printing the item.

(105) The revealing raster 4 may be associated, if relevant, with a printing pattern of the item.

(106) The pattern of the revealing raster 4 may be printed otherwise than by superposition with the combined image I, on the item, to the same scale or to a different scale.

(107) The printing of the revealing raster 4 may overrun the combined image I and extend over the secure item 10, as illustrated in FIG. 10.

(108) Several revealing rasters and combined images, having for example the form of small squares or rectangles with sides of a few millimeters, may be present in one and the same security thread 30, as illustrated in FIG. 11.

(109) When the revealing raster 4 and the combined image I are on a thread integrated as window(s), as illustrated in FIGS. 12A and 12B, the secure item 10 may comprise at least two windows 31 and 32 making it possible to observe respectively each of the faces of the thread, in reflection.

(110) The substrate of the item may comprise at the level of the windows 31 and 32 material voids and transparent regions 35 and 36 allowing the observation of the revealed images from both sides of the secure item 10.

(111) The interlaced images are observable through the revealing raster 4 from the window 31 side and with the revealing raster as background, from the window 32 side.

(112) The item 10 may also comprise a through window 31, as represented in FIG. 12D, the revealing raster 4 and the combined image I being situated at least partially in this through window. In this way, it is possible to observe the revealed images at one and the same time from the recto side and from the verso side of the secure item 10.

(113) The revealing raster 4 and the combined image in the form of a security thread may further be incorporated into a secure item 10 which exhibit an alternation of windows 31 and 32 recto side and verso side, as illustrated in FIG. 12C. It is thus possible to observe the revealed images at one and the same time on the recto side and on the verso side of the secure item 10 at the level of the windows 31 and 32, and especially on account of the presence of the material voids and the transparent regions 35 and 36.

(114) Represented in FIG. 13 is an exemplary secure item 10 comprising a perforation 40 in which two sub-elements, especially in the form of foils or patches, 41 and 42, are at least partially placed.

(115) The sub-element 41 comprises for example a revealing raster 4 and the sub-element 42 comprises for example the corresponding combined image I.

(116) The sub-elements 41 and 42 may be at least partially superposed on the boundaries of the perforation 40 with or without a thickness compensation.

(117) The sub-elements 41 and 42 may be at least partially transparent or translucent.

(118) The observation of the revealed images may be done by observation in reflection or in transmission, for example with the aid of a light source situated behind the item 10 during observation.

(119) In the variant illustrated in FIG. 14, the secure item 10 comprises a combined image I produced in the form of prints. The prints are for example produced on the surface of the secure item 10. Moreover, a sub-element 43, especially in the form of a foil or patch, is placed on the prints constituting the combined image I, the sub-element 43 comprising the corresponding revealing raster 4, for example produced on the surface of the sub-element 43.

(120) The secure item 10 may or may not be opaque. The secure item 10 may be at least partially transparent or translucent to allow observation of the interlaced images, especially on the combined image I side.

(121) In the examples of FIGS. 13 and 14, the revealing rasters 4 and/or the combined images I could be produced differently, being for example incorporated or situated above or below the sub-elements 41, 42 and 43.

(122) As a variant, the combined image comprises two metallizations of various colors, each corresponding to an interlaced image, especially a copper interlaced image and an aluminum interlaced image.

(123) As a further variant, the combined image comprises at least two metallizations, especially of the same color, of various optical densities and each corresponding to an interlaced image, thus creating a glossiness contrast.

(124) The aluminum interlaced image may be of high optical density, thereby giving it a glossy aspect.

(125) The revealing raster 4 may be of matt aspect.

(126) Superposition of the combined image I and of the revealing raster 4 makes it possible to obtain matt or glossy revealed images I.sub.r1 to I.sub.rg.

(127) Observation by Folding the Document or Superposing the Document and Another Object

(128) In a second embodiment, illustrated in FIG. 15, the secure item 10 comprises a window 50, preferably at least partially transparent, in which the revealing raster 4 is featured. The item 10 also comprises a combined image I carried on the item 10, for example by printing, especially copper-plate printing, offset printing or metallization and/or demetallization. The region in which the combined image 2 is featured may also be at least partially transparent.

(129) To observe the revealed image, the user must therefore fold the secure item 10, as illustrated in FIG. 17, to bring the revealing raster 4 onto the combined image I so that their general orientation is the same and then observe the revealed image or images I.sub.r. Thus, the revealed images are not visible when the item 10 is not folded and an action by the user, namely folding the secure item 10, is necessary in order to make them appear. This makes it possible to strengthen the security of the item 10.

(130) In FIG. 16, the secure item 10 comprises a window 50, preferably at least partially transparent, in which the combined image I is featured. The item 10 also comprises a patch 55 comprising for example holographic prints and in which the revealing raster 3 is featured. The patch 55 may also be at least partially transparent.

(131) The patch 55 may comprise metallizations and/or demetallizations, made for example of aluminum, and the revealing raster 4 may comprise holographic prints and/or metallizations and/or demetallizations.

(132) In FIG. 18, the item 10 comprises a window 50, preferably at least partially transparent, on which the revealing raster 4 is featured. The item 10 also comprises a security thread 60 on which the combined image I is featured. The security thread 60 may also be at least partially transparent or comprise a partially transparent region at the level of the combined image I.

(133) Represented in FIGS. 19 to 23 are other examples of secure item 10 according to the invention comprising a combined image I and a revealing raster 4 in accordance with those of FIGS. 15 and 16, the combined image I and/or the revealing raster 4 being carried by at least one security thread or foil.

(134) In FIG. 19, the item 10 comprises a security thread 60 of a sufficient width to cause combined images I and revealing rasters 4 to be featured in alternation. Advantageously, the security thread 60 is at least partially transparent or exhibits one or more at least partially transparent regions at the level of the combined images I and/or of the revealing rasters 4.

(135) In FIG. 20, the item 10 comprises a security thread 60 on which a revealing raster 4 is featured. The item 10 also comprises a combined image I, for example in the form of an offset print on the item 10.

(136) The security thread 60 may be at least partially transparent or exhibit an at least partially transparent region. The item 10 may also comprise an at least partially transparent region at the level of the combined image I.

(137) In FIG. 21, the item 10 comprises two security threads 60a and 60b. The security thread 60a comprises three combined images l and the security thread 60b comprises three revealing rasters 4.

(138) The security thread 60a and/or the security thread 60b may be at least partially transparent or comprise at least one at least partially transparent region, especially at the level of a combined image I or of a revealing raster 4.

(139) In FIG. 22, the item 10 comprises a foil 70 on which an alternation of combined images I and of revealing rasters 4 is featured.

(140) The foil 70 may be at least partially transparent or comprise at least one at least partially transparent region at the level of a combined image I and/or of a revealing raster 4.

(141) In FIG. 23, the item 10 comprises a security thread 60 on which a combined image I is featured. The item 10 also comprises a patch 55, able to comprise holographic metallizations or otherwise, on which a revealing raster 4 is featured.

(142) The security thread 60 may be at least partially transparent or comprise an at least partially transparent region at the level of the combined image I.

(143) The patch 55 may also be at least partially transparent, especially at the level of the revealing raster 4.

(144) In all the examples described previously, the combined images I and the revealing rasters 4 may be swapped.

(145) The at least partially transparent regions may be situated at the level of the combined images I or of the revelation means 4, or at the level of both at one time.

(146) The security thread or threads 60, 60a and 60b may be introduced into the secure item 10 in a conventional manner, for example at the surface, bulk-wise or as window(s).

(147) The authentication of the items 10 may be done by folding the items 10 lengthways or widthways so as to at least partially superpose the combined images I and the revealing rasters 4, and then to displace relative to one another so as to view for example the illusion of a motion and/or to modify the angle of observation of the combined images I and of the revealing rasters 4 superposed.

(148) As a further variant, it is also possible to superpose the item 10 at least partially with another similar item, such as described previously.

(149) Imager

(150) Represented in FIGS. 24 to 26 are examples of association between a secure item 10 and an electronic imager 100 making it possible to form the revealing raster 4 or the combined image I.

(151) In FIG. 24, the electronic imager 100 is for example a computer screen on which a first image 110 is displayed, the first image 110 being the revealing raster 4 or the combined image I.

(152) The secure item 10 is for example in the form of a banknote and comprises a second image 120, the second image being the revealing raster 4 if the first image is the combined image and vice versa.

(153) The secure item 10 is placed on the screen of the electronic imager 100 in such a way as to superpose the first image 110 at least partially with the second image 120 so as to observe the revealed image or images I.sub.r and deduce therefrom an authentication and/or identification piece of information in respect of the secure item 10.

(154) The secure item 10 may be displaced relative to the screen of the electronic imager 100 or the observer may change angle of observation to allow the observation of a change of the revealed image or images I.sub.r.

(155) As a variant, the referenced secure item 10 remains immobile with respect to the screen of the electronic imager 100 and the first image 110 is animated with a motion on the screen, for example a translation, for example with the aid of a program activated or not by the user.

(156) In FIG. 25, the electronic imager 100 is for example in the form of a digital projector, projecting a first image 110 onto a background 150, for example the wall of a room.

(157) The secure item 10 comprising the second image 120 may then be at least partially superposed with the first image 110 projected onto the background 150 to allow observation of the revealed image or images I.sub.r.

(158) In FIG. 26, the electronic imager 100 is a projector which projects the first image 110 directly on the secure item 10.

(159) The first image 110 may, as in the example of FIG. 26, be projected, for example in the form of a W, on a region of the secure item 10 where the second image 120 is not present. Next, the secure item 10 is for example folded on itself in such a way as to superpose the second image 120, for example in the form of an A, with the first image 110 projected by the electronic imager 100. The part of the secure item 10 comprising the second image 120 may in particular be folded down onto the part comprising the first image 110, this part remaining immobile, in such a way that the first image 110 is situated between the imager 100 and the second image 120.

(160) In a variant, not represented, the first image 110 is projected directly on the second image 120 of the item 10. In particular, the projection of the first image 110 on the second image 120 of the item 10 may allow an at least partial superposition of the first and second images. Next, the electronic imager 100 may be displaced relative to the item 10 so as to displace the revealing raster 4 with respect to the combined image I.

(161) Represented in FIG. 27 is a variant embodiment in which the electronic imager 100 is a screen displaying several first images 110a, 110b, 110c and 110d.

(162) The first images 110a to 110d may have different properties, for example different shapes, colors, dimensions, raster elements, in particular dots or lines.

(163) Advantageously, the first images 110a to 110d are differentiated in such a way as to allow one of them at least to be associated with at least one second image 120 present on an item 10. In this way, it is for example possible to authenticate and/or identify a greater diversity of items 10 having different respective second images, corresponding to the various first images 110a to 110d.

(164) As a variant, the item 10 comprises several different second images 120, as may be seen for example in FIG. 11, and the electronic imager 100 produces one or more first images 110. In this way, it is for example possible to authenticate and/or to identify a given security item 1 on a greater diversity of different electronic imagers, and especially with electronic imagers having different resolutions. In this way, the two advantages previously described may be brought together.

(165) The electronic imager 100 may display one or more indicators 140a, 140b, 140c and 140d making it possible to advise the user on the way to position the item 10 represented in FIG. 28 with respect to the imager.

(166) In particular, the indicators 140a to 140d may make it possible to know where to position the top right corner of the item 10, so as to correctly superpose a second image 120 of an item 10 with a first image 110a, 110b, 110c or 110d displayed on the screen of the electronic imager 100.

(167) The item 10 may comprise an integrated microcircuit 152, for example an RFID or optical chip, making it possible to communicate with the electronic imager 100 so as to control the display of an indicator such as described previously or to disseminate a piece of information on the way to position the first and second images.

(168) As a variant, the chip 152 is able to communicate with the electronic imager 100 so as to make it possible to produce the first image 110 associated with the second image 120.

(169) In particular, during the method for authenticating and/or identifying the item 10, the second image 120 is illuminated with the electronic imager 100. The chip 152 comprises a piece of information transmitted to the electronic imager 100 which then projects or displays the first image 110 as a function of this piece of information.

(170) The item 10, especially the second image 120, may be photographed and/or filmed by a digital camera belonging or linked to the electronic imager 100. A recognition program may then make it possible to recognize the second image 120 and to acquire from a database a first image 110 associated with the second image 120. The database is for example stored on a secure server. The first image 110 thus obtained is displayed and/or projected by the electronic imager 110 so as to make it possible to authenticate and/or to identify the item 10.

(171) As a variant illustrated in FIG. 29, the electronic imager 100 takes the form of a mobile telephone on which is displayed a first image 110 in the form of a combined image I. The item 10 comprises a polarizing filter on which the second image 120 has been formed in the form of a revealing raster 4. The item 10 comprising the second image 120 in the form of a revealing raster 4 is superposed with the first image 110 in the form of a combined image I produced by the electronic imager 100, the latter emitting polarized light.

(172) The item 10 comprising the revealing raster 4 may be displaced by a translation motion along the axis X with respect to the combined image I displayed by the screen of the electronic imager 100, in such a way as to change the revealed image or images I.sub.r.

(173) Such a method makes it possible to authenticate and/or to identify the security item 1 according to several security levels.

(174) The positioning of the revealing raster 4 comprising the polarizing filter according to the orientation making it possible to observe the opacity of the polarizing filter, this observation being visible only on a screen emitting a polarized light, for example a screen of the LCD type, affords a first level of security.

(175) The revealing of the animation of the revealed images by displacement of the revealing raster 4 relative to the combined image I affords a second level of security.

(176) As a further variant, the electronic imager 100 is a screen, especially of the LCD type, comprising a plurality of pixels preferably forming a combined image, for example such as described in FIG. 30A.

(177) The invention is not limited to the examples illustrated. The secure item may be produced with other securities of first, second or third level, for example.

(178) The expression comprising a should be understood as being synonymous with comprising at least one.