[0037] The procedure in accordance with the invention consists of definitively associating, by means of various embodiments, means that will be referred to hereinbelow as “the identifier” and means referred to hereinbelow as “the authentifier”, to form an optical complex that cannot be dissociated without being destroyed.

[0038] The identifier is, for example, a bar-code or a series of characters, preferably characters that can be interpreted by an optical character-reading (OCR) system, or even a photograph. The identifier makes it possible to implement a number of combinations determined by the type of marking required. The combinations can be determined in such a way as to allow automatic identification by a reader whose general operation is [the same as] that of the bar-code readers or optical character recognition [systems] in the prior art, or an infrared camera in the case of a photograph.

[0039] The authentifier consists of an interference pattern commonly referred to as a “hologram” that forms an indissociable part of the optical complex, which is read by the diffraction of incident light. It can reproduce a non-significant image, or can even include a portion of the information necessary for the identification of the product.

[0040] Depending on the variants of the embodiments, the diffraction patterns consist of:

[0041] A set of distinct points whose geometric characteristics are defined in relation to the position of the source and in relation to the theoretical position of the document;

[0042] A set of distinct lines or bars; or

[0043] A set of points that delineate a contour or an image.

[0044] The separation of the identifier and the authentifier is ensured by a wavelength-selective film overlay, and by the use of two different wavelength to read each of the two elements. Depending on the variant of the embodiment, the film overlay may be transparent in the visible spectrum or, alternatively, opaque in the visible spectrum and transparent in the infrared.

[0045] As an option, each of the elements may carry a portion of the information. In such a case, full identification is achieved by reading the information that is invisible under reflected light and [by] reading the information that is visible under diffracted light in a second wavelength band, and/or [through] verification of the correlation of the information coded by the identifier and the information coded by the authentifier.

[0046] FIG. 1 represents a view of a first example of an embodiment.

[0047] The product to be marked [1] has a printed region [2] carrying identification bar-odes. This region is covered by a multi-layer assembly [3] consisting of a label that can be affixed in such a way as to form an integral part of a product, by means of gluing or by heat-transfer, for which FIG. 2 represents an enlarged cross-sectional view.

[0048] This multi-layer assembly consists of:

[0049] A film substrate [ 25 ], such as for example a transparent polyester film. This film substrate [ 25 ] makes it possible to transfer the optical complex to the document or to the product to be marked and authenticated;

[0050] A detachment layer [ 26 ] allowing the separation of the film substrate [ 25 ] from the active portion of the label;

[0051] A protective film overlay [ 27 ] that is transparent over the entire spectrum;

[0052] A stamped transparent reflective layer [ 4 ]. This layer is rendered reflective by metallization or by the vaporization of an additional layer formed by a dielectric material or even by a film overlay whose index of refraction is different from that of the protective film overlay [ 27 ], with this layer carrying the authentification image by deformation of its surface;

[0053] A layer of film overlay [sic] [ 51 that is tinted in the visible [spectrum], allowing the passage of a narrow pass-band in the invisible [spectrum], for example, in the infrared range, with this layer of tinted film overlay [ 5 ] being opaque in the visible spectrum;

[0054] A layer of adhesive [ 6 ] whose characteristics are suited to the substrate, consisting for example of an adhesive that is reactive when heated.

[0055] The reflective layer [ 4 ] is deformed by stamping, with the aid of a matrix that includes optical information in the form of micro-relief elements.

[0056] A variant consists of providing an irregular detachment layer [ 26 ] that has regions with a high level of adhesion and regions with a low level of adhesion. When tractive force is applied to the film substrate [ 25 ], the active portions located under the strong adhesive are torn away from the substrate [ 1 ], while the active portions located under the weak adhesive remain affixed to the substrate [ 1 ] and form a set of spots or a significant assembly that allows the detect ion of an attempt at counterfeiting by tearing off the authentification label.

[0057] FIGS. 3 and 4 represent a variant of the embodiment of the multi-layer assembly [ 3 ].

[0058] In accordance with this variant, the multi-layer assembly forms a label incorporating the printed region [ 7 ] so as to form, for example, a bar-code. The printing is done with a conventional printing ink, or with an ink that is transparent in the visible [spectrum] and opaque only in the infrared [range]. The identifier [ 7 ] and the authentifier [ 4 ] are separated by the layer of film overlay [ 5 ] that is opaque in the visible [spectrum] and transparent in the infrared [range].

[0059] In both cases, the optical assembly [ 3 ] is deposited on the substrate [I] either cold, or by heat-lamination, or by a thermal-transfer process.

[0060] FIG. 5 represents a diagrammatic view of a device for reading the authentifier, in a variant of an embodiment in accordance with which the diffraction grating recreates an image that corresponds to a set of dots. The techniques for the implementation of a stamped diffraction grating or of a stamped holographic image are known to those skilled in the art, and will not be discussed in detail within the context of the present invention.

[0061] The reading device includes a light source, such as for example an electroluminescent [i.e., light-emitting] diode [ 10 ], that illuminates the optical complex [ 3 ] at a determined angle, with the angle of incidence being defined in relation to the [angle that is] normal to the plane of the diffraction grating. An aperture or pupil [ 14 ] and a focusing lens [ 15 ] are located along the optical path in order to form a light beam that illuminates the diffraction grating in a point-based manner.

[0062] A set of sensors [ 11 ] through [ 13 ] detects the light diffracted by the optical-complex grating [ 3 ]. The correspondence between the detected points of light and the diffraction pattern stored in a computer makes it possible to verify the authenticity of the marked-document. As an option, the identifier may be coded in accordance with the information derived from the diffraction pattern, and thus may vary from one document to another depending on a secret coding function stored in the verification equipment in the form of an algorithm for the comparison of the signals from the photo-detectors against the image calculated as a function of the information derived from the identifier and from the said algorithmn.

[0063] FIGS. 6 and 7 represent diagrammatic views of the reading of the authentifier in accordance with two different configurations, in accordance with a variant in which the diffracted pattern corresponds to bar-codes.

[0064] FIG. 6 and FIG. 7 represent a diagrammatic view of the result of the illumination of the optical complex [ 3 ] by a light source [ 10 ] along two different angles of incidence. The particular feature of certain diffraction gratings is that they produce a diffracted pattern that depends on the angle of incidence. Depending on the angle of incidence represented in FIG. 6 , or in FIG. 7 , the result will correspond to a first bar-code [ 16 ] or to a second barcode [ 17 ].

[0065] The reading device shown in FIG. 8 includes a bank of electroluminescent [sic] diodes [ 17 ] that includes a first series of electroluminescent diodes oriented along a first angle of incidence in relation to the [angle that is] normal to the substrate, for example, +45 degrees in relation to the normal [angle], and a second series of electroluminescent diodes oriented along a second, different angle of 45 degrees in relation to the normal [angle].

[0066] The reading device includes a CCD [charge-coupled device] sensor [ 18 ] that detects the diffracted pattern and that generates a signal that can be processed by a microcomputer in order to verify the correspondence between the diffracted pattern and the stored reference pattern or the identifier.

[0067] In the example described with reference to FIGS. 6 through 8 , the diffracted image corresponds to a bar-code. Of course, any type of grating may be recorded in the optical complex, in order to diffract images that correspond to texts, characters, or graphic information that can be recognized automatically by an optronic [i.e., opio-electronic] device, or by means of visual verification by an operator.

[0068] FIG. 9 represents an example of an embodiment of a reader, in the form of a portable device having a housing [ 20 ] in the form of a “shower-head”, whose rear portion encloses a CCD sensor array [ 21 ], and whose forward portion encloses an array [ 23 ] consisting of a set of electroluminescent [sic] diodes oriented along angles forming angles of +45 and −45 degrees in relation to the normal [angle] of a window that is open in the lower portion of the housing.

[0069] Optical focusing means [ 24 ] are provided in order to form, on the CCD transfer bar [sic; i.e., the CCD sensor array—Tr.] [ 21 ], the image diffracted by the diffraction grating placed against the window provided on the lower portion of the housing, after being reflected by a mirror [ 22 ].

[0070] Another method of implementing a reader for the reading and verification of a document marked with [sic] an optical complex of the type described above consists of combining, in a housing, means for recognizing information from the identifier, on the one hand, and means for the verification of the authentifier.

[0071] Such a reading device includes:

[0072] A series of laser diodes that illuminate the optical complex along one or more [angles of] incidence;

[0073] a CCD matrix or array, or june [sic; “une” (“one” or “a”) is most probably the intended word here—tr.] series of point receivers to analyze the response of the authentifier;

[0074] A specific reader for the identifier, functioning in the wavelength band suitable for the identifier, such as for example the infrared;

[0075] a computer for the processing of signals,

[0076] and output interfaces, such as for example a display or an RS-232 output for connection with a peripheral device:

[0077] The description of the invention in the foregoing text has been provided as a non-limitative example. It should be clearly understood that those skilled in the art will be capable of implementing different variants without departing from the scope of the invention in so doing.