Method for constructing a security feature in an at least partially transparent object and at least partially transparent object comprising a security feature

Abstract

The invention relates to a method for constructing a security mark (18) in the thickness of an object (1) made of an at least partially transparent amorphous, semi-crystalline or crystalline material, the object (1) comprising a top surface (2) and a bottom surface (4) at a certain distance from the top surface (2), the method comprising the following consecutive steps: obtaining a bare at least partially transparent object (1); providing one of the top surface (2) or the bottom surface (4) of the object (1) with a shielding body (6) defining at least one opening (8), the contour of which corresponds to the security mark to be constructed; The invention relates to a method for manufacturing an anti-counterfeiting mark (18) having a pseudo mark (18) shape, wherein a shield (6) covers the surface of an area of ​​the object where a pattern does not need to be constructed; bombarding the object (1) with a single-charged or multi-charged ion beam (14) through at least one opening (8) of the shield (6) to construct an anti-counterfeiting mark (18), wherein the mechanical properties of the shield (6) are sufficient to prevent ions of the ion beam (14) from etching the surface of an area of ​​the object (1) surface (2) that has been covered by the shield (6); removing the shield (6); and placing the object in a bath (16) having an alkaline pH.

Description

Technical Field

[0001] The invention relates to a method for constructing patterns with a technical or decorative function in at least partially transparent objects. The invention particularly relates to such a construction method using a singly or multiply charged ion beam. More specifically, the invention relates to a method for constructing patterns in objects made of at least partially transparent amorphous, semi-crystalline or crystalline materials. Background Art

[0002] Particularly in the field of watchmaking, the fight against counterfeiting is an increasing need. Therefore, marking technology is a valuable technology in the fight against counterfeiting. With regard to anti-counterfeiting markings in the field of watchmaking, the technology used for marking and the technology used to read these markings differ by two levels: in fact, it must be possible to successfully distinguish between authentic and counterfeit products.

[0003] The first security mark level corresponds to marks that anyone can confirm without using any reading device. Although such security marks can be recognized by anyone, these marks, such as holographic images, serve as warnings because their reproduction is complex. These security marks can also have an impact on the aesthetics of the objects they are used on. Level 1 security marks can usually be recognized with the naked eye. However, such security marks can involve other senses, such as touch, such as embossed prints.

[0004] The second marking level corresponds to markings that can only be identified with a reading device. There are two possible options: markings, such as bar codes, are visible to the naked eye, but their decoding requires a reader. These markings can be used to mark individual batches, products and contain many other information items. Alternatively, these markings are invisible. In this case, such markings can only be displayed with a reading device, for example using infrared or ultraviolet light that works at a wavelength of light.

[0005] Paradoxically, the reconfirmability of visible or easily visible security marks may be exploited by counterfeiters, which can affect consumer trust. It has been reported that counterfeit medical products containing holographic images are sold better than original medical products without holographic images. The main disadvantage of security marks that can be identified by consumers without the help of a reading device is that it is possible to immediately confirm the product to be counterfeited. Thus, counterfeiters can easily imitate the original product with their products. It may also be problematic to fix the visible security mark on the object without damaging the aesthetics. Security marks that are invisible to the naked eye are themselves more difficult to counterfeit because counterfeiters need to first confirm whether there is a security mark on the object. However, the method of making these marks is usually time-consuming and expensive. In addition, in order to show the presence of such invisible marks, in most cases, a specific decoder must usually be equipped. Therefore, this may sometimes require considerable investment, especially in the case of objects that are expected to detect objects from different manufacturers and use different security mark technologies. Therefore, it is usually impossible to guarantee that a suitable decoder can be provided when the authenticity of a specified product is expected to be ensured in most cases. Summary of the invention

[0006] It is an object of the present invention to provide a reliable and reproducible method for structuring a security feature in an at least partially transparent object.

[0007] To this end, the present invention relates to a method for building a security feature in the thickness of an object made of an at least partially transparent amorphous, semi-crystalline or crystalline material, said at least partially transparent object comprising a top surface and a bottom surface extending at a distance from said top surface, said method comprising the following successive steps:

[0008] - obtaining a bare at least partially transparent object;

[0009] - providing a masking body defining at least one opening to one of the top surface or the bottom surface of the at least partially transparent object, wherein the contour of the opening corresponds to the outer shape of the anti-counterfeiting mark to be constructed, and the masking body covers the surface of the area in which the pattern is not required to be constructed in the at least partially transparent object;

[0010] - constructing a security feature by bombarding an at least partially transparent object with a singly or multiply charged ion beam through at least one opening of a shielding body, the mechanical properties of the shielding body being sufficient to prevent ions from the ion beam from etching the surface of the at least partially transparent object in the area covered by the shielding body;

[0011] - Remove the shielding body;

[0012] - Placing the at least partially transparent object in a bath having an alkaline pH.

[0013] Based on these features, the present invention provides a method for forming a security mark in the thickness of an at least partially transparent object, and the method is reliable and reproducible. This mark that cannot be perceived by the naked eye can be very simply displayed by irradiating with a broad spectrum light source, such as a light source of a light emitting diode type. In fact, by following the steps of the inventive method, an at least partially transparent object is obtained, in which the change in reflectivity is displayed in the region where the security mark has been constructed, although this change is very small, it is enough to detect the security mark when irradiated. Therefore, one of the advantages of the present invention is that it is not necessary to use a specific and usually expensive device to ensure the authenticity of the object marked as described in the present invention. Only common commercially available broad spectrum light sources are sufficient. In addition, the security mark obtained by the inventive method is tamper-proof. For example, in the case of constructing this mark in a watch glass (watch crystal) made of sapphire, the only way to change this mark is to use diamond paste to polish this glass or melt this glass.

[0014] According to a particular embodiment of the method according to the invention, at least one antireflection coating is deposited on at least one of the top surface or the bottom surface of said object.

[0015] According to another specific embodiment of the method according to the invention, the at least partially transparent object is made of sapphire, ruby ​​or diamond, preferably of a synthetic material.

[0016] According to another particular embodiment of the method according to the invention, the at least partially transparent object is made of a semi-crystalline organic material.

[0017] According to another specific embodiment of the method according to the invention, the at least partially transparent object is made of mineral glass or an amorphous organic material.

[0018] According to another specific embodiment of the method according to the invention, the at least partially transparent object is pre-washed.

[0019] According to another specific embodiment of the method of the present invention, the singly or multiply charged ion beam is generated by an ECR electron cyclotron resonance type singly or multiply charged ion source.

[0020] According to another specific embodiment of the method of the present invention, the at least partially transparent object is made of nitrogen N, oxygen O, helium He, carbon C, argon Ar, xenon Xe, carbon tetrafluoride CF 4 or methane CH 4 of ions for bombardment.

[0021] According to another specific embodiment of the method of the present invention, the ions are accelerated at a voltage of 10 kV to 40 kV, and the ion implantation dose is 3·10 16 Until June 1016 ions / cm 2 .

[0022] According to another specific embodiment of the method of the present invention, the at least partially transparent object is accelerated at 1.53 s / cm at a voltage of 28 kV. 2 time, and the ion implantation dose is 3.5·10 16 ions / cm 2 , and the ion beam intensity is 5.5 mA.

[0023] According to another embodiment of the method of the invention, the masking body is a sheet material in which the outline of the security mark has been left out, and this sheet material is subsequently fixed to the top surface of the at least partially transparent object where the pattern is to be constructed.

[0024] According to other specific embodiments of the method of the present invention:

[0025] - the shielding body deposited on the surface of the at least partially transparent object is a metal coating formed by metal plating;

[0026] - the metallization is carried out by vapor deposition via one of the following techniques: physical vapor deposition (PVD), chemical vapor deposition (CVD), plasma enhanced chemical vapor deposition;

[0027] - the metal coating is a coating of chromium nitride CrN, and its thickness is 1 to 1500 nm;

[0028] Arranging at least one opening in the metal coating by photolithography, the contour of which corresponds to the outer shape of the security feature to be produced in the at least partially transparent object.

[0029] According to another particular embodiment of the method according to the invention, the at least partially transparent object is a watch glass. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Other features and advantages of the present invention are further explained below by a detailed description of an embodiment example of the method of the present invention with reference to the accompanying drawings. This example is only for illustrative purposes and does not have any limiting effect. In the accompanying drawings:

[0031] - Figure 1 is a cross-sectional view of a watch glass having an obscuring coating deposited on its top surface;

[0032] - Figure 2 Yes Figure 1 A cross-sectional view of a watch glass shown in which the obscuring coating is covered by a photosensitive resin coating;

[0033] - Figure 3 Yes Figure 2 A cross-sectional view of a watch glass is shown wherein a photosensitive resin coating is exposed to light, only a portion of the photosensitive resin coating being exposed to photopolymerization;

[0034] - Figure 4 Yes Figure 3 A cross-sectional view of a watch glass is shown showing the development of a photosensitive resin coating, where only the portion of the photosensitive resin coating exposed to light remains, while the portion not exposed to light has been removed;

[0035] - Figure 5 Yes Figure 4 A cross-sectional view of a watch glass is shown with those portions of the masking coating not covered by the photosensitive resin coating which has been exposed to light removed;

[0036] - Figure 6 Yes Figure 5 A cross-sectional view of a watch glass is shown, wherein the remaining part of the photosensitive resin coating has been removed, wherein the top surface of the watch glass is covered by an area of ​​the masking coating, which forms a masking body, wherein the contour of the opening corresponds to the outer shape of the security feature to be constructed in the thickness of the watch glass;

[0037] - Figure 7 Yes Figure 6 A cross-sectional view of a watch glass shown, wherein the anti-counterfeiting mark of the watch glass is formed by bombarding the watch glass with an ion beam through an opening of a shield;

[0038] - Figure 8 Yes Figure 7 A cross-sectional view of a watch glass shown, wherein the watch glass is placed in a bath having an alkaline pH;

[0039] - Fig. 9 Displays the use of light sources to detect anti-counterfeiting marks;

[0040] - Fig.10 is a cross-section of a watch glass on which an anti-reflective coating has been deposited on the front and back surfaces. DETAILED DESCRIPTION

[0041] The present invention is based on an overall inventive concept, which includes a method for anti-counterfeiting marking of at least partially transparent objects, which method can be integrated into a large-scale production cycle without difficulty. In addition, the mark constructed by the method of the present invention is invisible to the naked eye and can be detected by a broad spectrum light source available to anyone. Therefore, the authenticity of the object marked according to the present invention does not need to be identified by a specific decoder, which is usually expensive and the place where the observation is to be carried out cannot always ensure that it is equipped with a decoder. Similarly, the anti-counterfeiting marks obtained according to the present invention are basically unchangeable, and the only way to remove these marks is usually to destroy the marked object.

[0042] In the following example, a method for constructing an anti-counterfeiting mark in a sapphire watch glass according to the method of the present invention is described. Obviously, this example is only for illustrative purposes and does not have any limiting effect, and the method of the present invention can be applied to mark any at least partially transparent object made of amorphous, semi-crystalline or crystalline material.

[0043] Designated as a whole by the general reference numeral 1 is a watch glass made of sapphire, which comprises a top surface 2 and a bottom surface 4 extending at a distance from the top surface 2. In the example shown in the figures, a security feature is formed in the top surface 2 of the watch glass 1. Obviously, this security feature can also be formed in the bottom surface 4 of the watch glass 1.

[0044] Once such a watch glass 1 is obtained, its top surface 2 is first provided with a shielding body 6 which will delimit at least one opening 8, the contour of which will correspond to the outer shape of the security feature to be constructed in the thickness of the watch glass 1. According to a first embodiment of the invention (not shown in the drawings), the shielding body 6 is a separate sheet of material in which the contour of the security feature has been left out, which sheet of material is then fixed to the top surface 2 of the watch glass 1.

[0045] According to a preferred embodiment of the method of the invention, the shielding body 6 is formed by photolithography directly on the top surface 2 of the watch glass 1. For this purpose, the top surface 2 of the watch glass 1 is first covered with a shielding coating 10 of the material required to form the shielding body 6 (see Figure 1 The thickness of the shielding coating 10 is preferably 1 to 1500 nm. The shielding coating 10 can be prepared by vapor deposition of a metal material, such as chromium nitride Cr. x N y , such as CrN, by one of the following techniques: physical vapor deposition or PVD, chemical vapor deposition or CVD, or plasma enhanced chemical vapor deposition or PECVD.

[0046] After the deposition of the shielding coating 10, this layer is covered with a photosensitive resin coating 12 (see Figure 2 Then, the photosensitive resin coating 12 is exposed to light so that only a portion of the photosensitive resin coating 12 is exposed to photopolymerization (see Figure 3 Then, the photosensitive resin coating 12 is developed, and only the portion 12a of the photosensitive resin coating 12 that has been exposed to light remains, while the portion 12b that has not been exposed to light is removed (see Figure 4 Finally, the portion of the masking coating 10 not covered by the photosensitive resin coating 12 is removed, for example, by chemical etching (see Figure 5); the portion 12a of the photosensitive resin coating 12 that has been exposed to light is subsequently removed. This results in a watch glass 1 in which the top surface 2 is covered by an area of ​​the masking coating 10, which forms a masking body 6, in which the contour of the one or more openings 8 corresponds to the outer shape of the security feature to be constructed in the thickness of the watch glass 1 (see Figure 6 ).

[0047] After the masking coating 10 has been appropriately structured by photolithography to form the masking body 6, the watch glass 1 is subjected to an anti-counterfeiting marking operation. For this purpose (see Figure 7 ), the watch glass 1 is bombarded by a singly or multiply charged ion beam 14 through at least one opening 8 of a shield 6, the mechanical properties of the shield 6 being sufficient to prevent ions from the ion beam 14 from etching the top surface 2 of the watch glass 1 in the area covered by the shield 6. According to a preferred embodiment of the method of the present invention, nitrogen N, oxygen O, helium He, carbon C, argon Ar, xenon Xe or by carbon tetrafluoride CF 4 or methane CH 4 The ions of carbon C obtained by ionization are used to bombard the watch glass 1. To accelerate these ions, a single-charged or multi-charged ion source of the ECR electron cyclotron resonance type can be used. Preferably, the ions are accelerated at a voltage of 10 kV to 40 kV, and the ion implantation dose is 3·10 16 Until June 10 16 ions / cm 2 In the specific case of bombarding the watch glass 1 with nitrogen N ions, the nitrogen N ions are accelerated at a voltage of 28 kV to 1.53 s / cm 2 time, where the ion implantation dose is 3.5·10 16 ions / cm 2 , and the ion beam intensity is 5.5 mA.

[0048] After the watch glass 1 has been bombarded with ions in order to build up the desired security feature in its thickness, the mask 6 is removed and the watch glass 1 is subsequently placed in a bath 16 having an alkaline pH (see Figure 8 An example of a bath suitable for placing the watch glass 1 after the construction of the security feature may be the product from Borer under the name Deconex OP 141. The bath comprises a solution based on potassium hydroxide, wherein the pH is equal to 13.

[0049] The security feature 18 obtained by the method according to the invention is invisible to the naked eye, but can be displayed very simply by irradiating it with a broad-spectrum light source 20, for example of the light-emitting diode type (see Fig. 9). In fact, by following the steps of the invention, a transparent watch glass 1 is obtained which, in the area in which the security mark 18 has been constructed, shows a variation in reflectivity which, although small, is sufficient to allow the security mark 18 to be detected when illuminated by the light source 20. Therefore, one of the significant advantages of the invention is that it is not necessary to use specific and usually expensive devices to confirm the authenticity of the object marked according to the invention. For example, a light source 20 suitable for use in the invention is a common lamp sold by TANEO as STZL 24R, in which the white color temperature is 4700 to 5300 ° K.

[0050] Before providing the security feature, the watch glass 1 may be pre-washed to degrease it.

[0051] After the security feature has been built into the thickness of the watch glass 1 , one or more anti-reflective coatings 22 , 24 may additionally be deposited on one or both of the top surface 2 or the bottom surface 4 of the watch glass 1 (see Fig.10 The anti-reflection coatings 22 and 24 are made of, for example, silicon dioxide (SiO 2 ) or magnesium fluoride (MgF 2 ). A coating made of silicon dioxide and a coating made of magnesium fluoride can be combined. The thickness of these coatings is considered to be generally not more than 150nm independently. Other materials can also be used to prepare anti-reflection coatings, such as oxides of titanium, tantalum, zirconium, silicon and aluminum, and silicon nitride. These anti-reflection coatings 22, 24 can be deposited by vapor deposition. Among the deposition techniques that can be considered, physical vapor deposition (PVD), chemical vapor deposition (CVD), plasma enhanced chemical vapor deposition (PECVD), or atomic layer deposition or ALD can be mentioned. A coating made of silicon dioxide and a coating made of magnesium fluoride can be combined. The thickness of these coatings is considered to be generally not more than 150nm independently. Other materials can also be used to prepare anti-reflection coatings, such as oxides of titanium, tantalum, zirconium, silicon and aluminum, and silicon nitride.

[0052] Obviously, the invention is not limited to the above-described embodiments and various modifications and simple variants can be envisaged without departing from the scope of the invention as defined in the appended claims. In particular, the invention is described by way of example using a watch glass made of sapphire. Obviously, however, the invention is not limited to this specific embodiment and can be applied to any type of at least partially transparent object made of sapphire, ruby ​​or diamond, preferably made of synthetic material. The invention can also be applied to at least partially transparent objects made of semi-crystalline organic materials, such as mineral glass or amorphous organic materials.

[0053] Reference Symbols List:

[0054] 1. Watch glass

[0055] 2. Top surface

[0056] 4. Bottom surface

[0057] 6. Shielding

[0058] 8. Open your mouth

[0059] 10. Masking coating

[0060] 12. Photosensitive resin coating

[0061] 12a. Portions of the photosensitive resin coating that have been exposed to light

[0062] 12b. Portions of the photosensitive resin coating not exposed to light

[0063] 14. Ion beam

[0064] 16. Bath

[0065] 18. Anti-counterfeiting mark

[0066] 20. Light Source

[0067] 22,24. Anti-reflective coating.

Claims

1. A method for constructing a security mark (18) in the thickness of an object (1) made of an at least partially transparent amorphous, semi-crystalline or crystalline material, the at least partially transparent object (1) comprising a top surface (2) and a bottom surface (4) extending at a distance from the top surface (2), the method comprising the following consecutive steps: - obtaining a bare at least partially transparent object (1); - providing a masking body (6) defining at least one opening (8) to one of the top surface (2) or the bottom surface (4) of the at least partially transparent object (1), wherein the contour of the opening corresponds to the outer shape of the anti-counterfeiting mark to be constructed, and the masking body (6) covers the surface of the area of ​​the at least partially transparent object (1) where the pattern does not need to be constructed; - constructing a security feature by bombarding the at least partially transparent object (1) with a singly or multiply charged ion beam (14) through at least one opening (8) of a shield (6), the mechanical properties of the shield (6) being sufficient to prevent ions from the ion beam (14) from etching the surface of the at least partially transparent object (1) in the area covered by the shield (6); - removing the shielding body (6); - placing the at least partially transparent object (1) in a bath (16) having an alkaline pH, The invention is characterized in that the bombardment of the ion beam causes a change in the reflectivity of the object (1) so that the anti-counterfeiting mark (18) is invisible to the naked eye but can be detected by a light source of the white light emitting diode type.

2. The method according to claim 1, Features At least one anti-reflective coating (22, 24) is deposited on at least one of the top surface (2) or the bottom surface (4).

3. The method according to any one of claims 1 and 2, Features The at least partially transparent object (1) is made of sapphire, ruby ​​or diamond, preferably of a synthetic material.

4. The method according to any one of claims 1 and 2, Features The at least partially transparent object (1) is made of a semi-crystalline organic material.

5. The method according to any one of claims 1 and 2, Features The at least partially transparent object (1) is made of mineral glass or an amorphous organic material.

6. The method according to any one of claims 1 to 5, Features The at least partially transparent object (1) is pre-washed.

7. The method according to any one of claims 1 to 6, Features The singly or multiply charged ion beam (14) is generated by an ECR electron cyclotron resonance type singly or multiply charged ion source.

8. The method according to claim 7, Features The at least partially transparent object (1) is made of nitrogen N, oxygen O, helium He, carbon C, argon Ar, xenon Xe or by mixing carbon tetrafluoride CF 4 or methane CH 4 The ionized carbon C ions are bombarded.

9. The method according to claim 8, Features The ions are accelerated at a voltage of 10 kV to 40 kV, and the ion implantation dose is 3×10 16 Up to 6×10 16 ions / cm 2 .

10. The method according to claim 9, Features The at least partially transparent object (1) is accelerated at 1.53 s / cm at a voltage of 28 kV. 2 time, and the ion implantation dose is 3.5×10 16 ions / cm 2 , and the ion beam intensity is 5.5 mA.

11. The method according to any one of claims 1 to 10, Features The masking body (6) is a sheet material in which the outline of the security mark has been left out, and this sheet material is then fixed to the top surface (2) or bottom surface (4) of the at least partially transparent object (1) where the shape is to be constructed.

12. The method according to any one of claims 1 to 10, Features The shielding body (6) deposited on the top surface (2) or the bottom surface (4) of the at least partially transparent object (1) is a metal coating formed by metal plating.

13. The method according to claim 12, Features The metallization is performed by vapor deposition via one of the following techniques: physical vapor deposition (PVD), chemical vapor deposition (CVD), plasma enhanced chemical vapor deposition.

14. The method according to claim 13, Features The metal coating is a chromium nitride (CrN) coating with a thickness of 1 to 1500 nm.

15. The method according to any one of claims 12 to 14, Features At least one opening (8) is arranged in the metal coating by photolithography, the contour of which corresponds to the outer shape of the security feature to be formed in the at least partially transparent object (1).

16. The method according to any one of claims 1 to 15, Features The at least partially transparent object (1) is a watch glass.

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