Device and method for producing and detecting a forgery-proof identification

Abstract

The invention relates to a method and a device (100) for forming a two-dimensional or three-dimensional micro-structured identification structure (200) in a defined surface region (12) in a surface (11) of a component (10) or product.

Claims

1. A device for forming a two-dimensional or three-dimensional microstructured identification structure in a defined surface region in a surface of a component or product, said device comprising: a) a laser device for generating at least one laser beam; b) a control device for the variable control and setting of the laser beam or beams; c) hardware and software for generating control commands for the control device from at least pattern data of a certain two-dimensional or three-dimensional pattern (M) and coding data for controlling the laser beams in such a way that the two-dimensional or three-dimensional microstructured identification structure can accordingly be formed in the defined surface region, wherein the coding data is integrated within the two-dimensional or three-dimensional pattern (M) in a manner which is imperceptible to the human eye.

2. The device as claimed in claim 1, wherein the coding data for coding a pattern (M) to be generated on the surface of a component is stored in software of the device as an algorithm.

3. The device as claimed in claim 1, wherein furthermore an input device is provided, to input component-specific data of the component to be provided with the identification structure.

4. A decoding device comprising an optical detection unit for reading the coding from a two-dimensional or three-dimensional microstructured identification structure generated using the device according to claim 1, in a defined surface region in a surface of a component.

5. The device of claim 1, wherein the generated maximum depth of the two-dimensional or three-dimensional microstructured identification structure in the defined surface region measured in relation to the region of the surface surrounding the surface region is in a range from 300 nm to 300 μm.

6. The device of claim 1, wherein the height differences within the identification structure, which were generated by the coding in relation to the uncoded pattern (M), are in the range from 500 nm to 10 μm.

7. A method for forming a forgery-proof identification on a surface of a component or product using a device as claimed in claim 1, comprising: a. irradiating a surface of a component or product in a defined surface region using at least one laser beam of the laser device; b. adapting the laser beam in dependence on the region of incidence (Δx, Δy) of the laser beam or beams by means of a control unit in accordance with a defined control algorithm to generate a respective specific laser beam in the defined region of incidence (Δx, Δy) of the surface region; and c. generating a three-dimensional microstructured identification structure in the defined surface region to form an identification in such a way that the microstructured surface integrates a non-coded structure with a coding wherein said coding is not perceptible to the human eye.

8. The method as claimed in claim 7, wherein the control algorithm for controlling and adapting the laser beam is generated at least from the pattern data of a pattern (M) to be generated and the coding data of a desired coding.

9. The method as claimed in claim 7, wherein furthermore data correlating with the specific function of the surface, which can preferably be input via an input unit, are incorporated into the control algorithm for controlling and adapting the laser beam.

10. The method as claimed in claim 7, wherein the generated maximum depth of the two-dimensional or three-dimensional microstructured identification structure in the defined surface region measured in relation to the region of the surface surrounding the surface region is in a range from 300 nm to 300 μm.

11. The method as claimed in claim 10, wherein the generated maximum depth of the two-dimensional or three-dimensional microstructured identification structure in the defined surface region measured in relation to the region of the surface surrounding the surface region is in a range from 750 nm to 10 μm.

12. The method as claimed in claim 7, wherein the height differences within the identification structure, which were generated by the coding in relation to the uncoded pattern (M), are in the range from 500 nm to 10 μm.

13. The method as claimed in claim 12, wherein the height differences within the identification structure, which were generated by the coding in relation to the uncoded pattern (M), are in the range from 750 nm to 2.5 μm.

14. The method as claimed in claim 7, wherein the pattern (M) in the microstructured identification structure is introduced into the surface in a form which is visually readable by a human with the naked eye without the use of a technical device and/or is optically perceptible, while the coding contained in the microstructured identification structure can be registered only by a suitably configured decoding device.

15. A component, which has a two-dimensional or three-dimensional microstructured identification structure, which has a superposition of a two-dimensional or three- dimensional pattern (M) with a coding which can be registered only by means of a suitable decoding device, in a surface region of a surface of the component wherein the microstructured identification structure is produced using a method as claimed in claim 7, wherein laser interference patterns which were introduced during the method are recognizable within the structure.

Description

(1) In the figures:

(2) FIG. 1 shows two different coded microstructured identification structures of a pattern in a top view;

(3) FIG. 2 shows a microstructured identification structure in a sectional view;

(4) FIG. 3 shows an exemplary embodiment of a device for forming a two-dimensional or three-dimensional microstructured identification structure; and

(5) FIG. 4 shows a piston rod of a gas pressure spring.

(6) The invention will be explained in greater detail hereafter on the basis of exemplary embodiments, wherein identical reference signs indicate identical functional and/or structural features.

(7) In FIG. 1, two different coded microstructured identification structures 200 of a pattern M are shown in a top view and, underneath this in FIG. 2, an exemplary microstructured identification structure 200 is shown in a sectional view in a component 10 having a surface 11 in a surface region 12.

(8) The dashed line L represents the surface in the state before the irradiation using laser beams 20′. The pattern M shown in FIG. 1 was overlaid by means of a depth coding K, whereby a specific coded depth profile results. The pattern M was decomposed in this exemplary embodiment into a plurality of segments in a grid along a x axis and y axis and a coding depth T was assigned to each segment according to a predefined coding algorithm. A respective region of incidence Δx, Δy in the projected plane of the surface 11 is associated with the corresponding segment on the surface of the component to be identified in a surface region 12. The laser intensity is adapted in this region of incidence Δx, Δy in accordance with the coding information supplied by software, so that the desired structure depth T is achieved in this region of incidence Δx, Δy. The structure depth T is measured as the level difference between the dashed line L and the level of the structure in the affected segment of the microstructured identification structure 200.

(9) An exemplary embodiment of a device 100 for forming a two-dimensional or three-dimensional microstructured identification structure 200 is shown in FIG. 3, in order to generate a defined surface region 12 as shown in FIGS. 1 and 2 in a surface 11 of a component 10 or product. The device 100 comprises a laser device 110 for generating at least one laser beam 20, a control device 120 for the variable control and setting of the laser beam or beams 20, and hardware 130 and software 140 for generating control commands for the control device 120 from at least pattern data of a certain two-dimensional or three-dimensional pattern M, which are input and/or stored in a memory 150, and also coding data for controlling the laser beams 20.

(10) The laser device 110 for generating the laser beams 20 is configured as multibeam laser interference technology, in which, for example, a frequency-multiplied Nd:YAG laser having a wavelength of 355 nm, a pulse energy of 13 mJ, and a pulse length of 38 ns at a repetition rate of 15 kHz is shown as the beam source.

(11) In the exemplary embodiment shown, the polarization of the collimated laser beam takes place with the aid of a half-wave plate, in which the laser beam is rotated by 90°, so that the laser beam is polarized perpendicularly to the plane of incidence. The monitoring and variation of the polarization direction of the exceptional laser beam can be performed with the aid of conventional means (for example, a half-wave plate).

(12) Furthermore, an optical unit 160 is provided, which comprises a diffractive optical element as a beam splitter, namely for splitting the laser beam 20 into two split laser beams 20′, in the exemplary embodiment. Beam splitters which generate more than two laser beams are also conceivable.

(13) With the aid of a manipulator 170 and a multiaxis displacement assembly 180, the component 10 may be aligned exactly in relation to the laser beams 20, on the one hand, and may thus also be displaced in at least two axes x, y to generate a planar structuring 200.

(14) After a deflection of the laser beam by 90°, the light is conducted through a spatial filter and optionally lenses (not shown in greater detail).

(15) The laser beam 20 may be adjusted to the desired beam diameter by displacing the lens or setting the optical unit 160. For example, the fluence (energy density per unit of area) may be varied as intended by variation of the beam diameter.

(16) The two-beam splitter of the optical unit 160 can consist, for example, of a dielectrically coated glass substrate, which splits the laser beam into two coherent partial beams of equal intensity. The partial beams 20′ having a laser angle in relation to the optical axis of the laser beam 20 are therefore incident on at least one optical element 161 of the optical unit 160, which is highly transparent to the laser radiation. This optical element is provided in such a way that the laser beams 20′ are optically refracted by the optical element and are changed in the radiation direction thereof.

(17) Furthermore, a radiation bundling unit 190 is connected downstream, in which the previously split laser beams 20′ are unified again. Different interference periods may be set by way of the intentional variation of optical and geometrical variables, for example, the angle conditions. Thus, for example, the interference period may be influenced by a variable distance of the diffractive optical element (beam splitter) and the further optical element (beam unifier).

(18) The control device 120 is accordingly used for the intended control and setting of the laser beam or beams 20 in relation to at least the interference period thereof and preferably also for the control and setting of the radiation intensity. To imprint a coding, an algorithm is used, using which, for example, a time-dependent setting and control of the interference periods and preferably also the control and setting of the radiation intensity is carried out directly or indirectly.

(19) The component movement in relation to the laser region of incidence is carried out with the aid of the manipulator 170 and a multiaxis displacement assembly 180. While a structure corresponding to the laser intensity and/or the interference periods is formed simultaneously via the control device 120 of the laser beams on the area of incidence of the component surface, a two-dimensional or three-dimensional pattern M can be generated in the component surface with minimal structural depth by moving the laser beam controlled using an algorithm, wherein the coding imprinted by the algorithm is included overlaid in the pattern.

(20) It is particularly advantageous if the laser beam 20 is emitted by a laser beam source 110 operated in a pulsed manner. It can furthermore be provided that the pulse frequency is controlled by the or a further control device 120 in such a way that in this way the laser energy incident per time interval on a surface element (region of incidence (Δx, Δy)) is settable and a different structure depth may be achieved in the micro-region, which is not visible to the naked eye of an observer. It is particularly advantageous if software 140 is implemented in the device, which automatically performs the control during the laser process according to retrievable pattern data and coding data.

(21) Furthermore, a decoding device 200 not associated with the device 100 is shown in FIG. 3, which has hardware and software, and also an optical detection unit for reading the pattern and the coding.

(22) A piston rod 10 of a gas pressure spring is shown as the component 10 in FIG. 4. The piston rod 10 has a cylindrical piston sealing surface 10a. The piston sealing surface 10a works together with a seal element 10b. A three-dimensional microstructured identification structure 200 is introduced into the piston sealing surface 10a in a surface region 12 as a superposition of a two-dimensional pattern M (as shown in FIG. 1) with a coding K.

(23) Because of the microstructure depth generated using the method according to the invention in the above-explained depth ranges, the piston rod is provided with an identification which is unambiguously perceptible by an observer, on the one hand, and with a coding integrated in the identification which is not recognizable by a person with the naked eye, on the other hand, and has its seal function in relation to the seal element even in the surface region 12 into which the identification structure 200 is introduced, on the other hand.

(24) The invention is not restricted in its embodiment to the preferred exemplary embodiments specified above. Rather, a number of variants are conceivable, which make use of the described solution even in fundamentally differently designed embodiments.