Method, device and security system, all for authenticating a marking

• US 20040031931A1
• Filed: 11/05/2002
• Published: 02/19/2004
• Est. Priority Date: 05/16/2000
• Status: Active Grant

• Current Assignee: Sicpa Holding SA
• Original Assignee: Sicpa Holding SA
• Inventors: Müller, Edgar, Seto, Myron, Egger, Philipp
• Granted Patent: US 7,067,824 B2
• Time in Patent Office: Days
• US Class Current: 250/458.1
• CPC Class Codes: G06K 19/14 the marking being sensed by radiation
• CPC Class Codes: G07D 7/12 Visible light, infrared or ultraviolet radiation
• CPC Class Codes: G07D 7/121 Apparatus characterised by sensor details

Abstract

The invention refers to a method, device and security system, all for authenticating a marking (M-P), comprising the steps of: exciting said luminescent probe marking (M-P) with at least one excitation pulse (P) of at least one excitation source (3, 31-36), measuring probe intensity values (V_P1-V_Pn) of emission intensity (I) from emission radiation (E) of said luminescent probe marking (M-P) in response to said at least one excitation pulse (P) at time intervals (t₁-t_n), forming a probe intensity-versus-time emission function of said probe intensity values (V_P1-V_Pn), comparing said probe intensity-versus-time emission function with at least one reference intensity-versus-time emission function, said probe intensity-versus-time emission function and said reference intensity-versus-time emission function are normalized prior to comparison.

Claims

1. Method for authenticating a luminescent probe marking (M-P), comprising the steps of:

exciting said luminescent probe marking (M-P) with at least one excitation pulse (P) of at least one excitation source (3, 31-36),

measuring probe intensity values (V_P1-V_Pn) of emission intensity (I) from emission radiation (E) of said luminescent probe marking (M-P) in response to said at least one excitation pulse (P) at time intervals (t₁-t_n),

forming a probe intensity-versus-time emission function of said probe intensity values (V_P1-V_Pn),

comparing said probe intensity-versus-time emission function with at least one reference intensity-versus-time emission function,

said probe intensity-versus-time emission function and said reference intensity-versus-time emission function are normalized prior to comparison.

2. Method according to claim 1, characterized in that at least one luminescent probe marking (M-P) is part of a probe sample (7-P) to be authenticated and that specific emission characteristics of said at least one luminescent probe marking (M-P) are measured, said specific emission characteristics include at least one excitation wavelength of said excitation pulse (P), at least one emission wavelength of said emission radiation (E) and probe intensity values (V_P1-V_Pn) of emission intensity (I) at time intervals (t₁-t_n) for at least one of said emission wavelength.

3. Method according to claim 1 or 2, characterized in that at least one luminescent reference marking (M-R) is part of a reference sample (7-R) and that specific emission characteristics of said at least one luminescent reference marking (M-R) are measured, said specific emission characteristics include at least one excitation wavelength of said excitation pulse (P), at least one emission wavelength of said emission radiation (E) and reference intensity values (V_R1-V_Rn) of emission intensity (I) at time intervals (t₁-t_n) for at least one of said emission wavelength.

4. Method according to claim 3, characterized in that reference intensity values (V_R1-V_Rn) and/or at least one reference intensity-versus-time emission function is/are stored in at least one memory device (1c, 1d).

5. Method according to claim 4, characterized in that said at least one reference intensity-versus-time emission function is stored in a normalized form and/or in a non-normalized form.

6. Method according to one of the preceding claims, characterized in that said luminescent probe marking (M-P) respectively reference marking (M-R) is excited with at least one excitation pulse (P) from at least one excitation source (3, 31-36) being a laser and/or a light emitting diode.

7. Method according to one of the preceding claims, characterized in that said luminescent probe marking (M-P) respectively reference marking (M-R) is excited with at least one excitation pulse (P) of electrons.

8. Device for authenticating a luminescent probe marking (M-P), comprising:

at least one detector (4, 41, 42, 4b) for measuring probe intensity values (V_P1-V_Pn) of emission intensity (I) from emission radiation (E) of said luminescent probe marking (M-P) in response to at least one excitation pulse (P) generated by at least one excitation source (3, 31-36) at time intervals (t₁-t_n)

at least one processor (1) for forming probe intensity-versus-time emission function of said probe intensity values (V_P1-V_Pn),

at least one processor (1) for comparing said probe intensity-versus-time emission function with at least one reference intensity-versus-time emission function and

at least one processor (1) for normalizing said probe intensity-versus-time emission function prior to comparison with a normalized reference probe intensity-versus-time emission function.

10. Device according to claim 8 or 9, characterized in that it comprises at least one memory device (1c, 1d) for storing reference intensity values (V_R1-V_Rn) of emission intensity (I) at time intervals (t₁-t_n) for at least one wavelength of emission radiation (E) of said luminescence reference marking (M-R) and/or for storing at least one reference intensity-versus-time emission function formed from reference intensity values (V_R1-V_Rn).

12. Device according to one of claims 8 to 11 characterized in that said at least one detector (4) comprises a wavelength selector (4a′

).

13. Device according to one of claims 8 to 12, characterized in that said at least one detector (4, 41, 4b) converts emission intensity (I) into electric signals of probe intensity values (V_P1-V_Pn) respectively of reference intensity values (V_R1-V_Rn) and that said at least one processor (1) samples said electric signals to form a probe intensity-versus-time emission function of said probe intensity values (V_P1-V_Pn) respectively to form a reference intensity-versus-time of reference emission function of said reference intensity values (V_R1-V_Rn).

14. Device according to one of claims 8 to 13, characterized in that it comprises at least one spectrometer for differentiating between two or more emission wavelengths and that said at least one detector (4b) is an array-photodetector for measuring the emission radiation (E) at two or more emission wavelengths, allowing a simultaneous measuring of probe intensity values (V_P1-V_Pn) of emission radiation (E) of a luminescent probe marking (M-P) respectively a simultaneous measuring of reference intensity values (V_R1-V_Rn) of emission radiation (E) of a luminescent reference marking (M-R).

15. Device according to claim 14, characterized in that said at least one array-photodetector (4b) is a two-dimensional CCD array, a first row of photosensitive pixels (PIX) works as as photodetecting array, the remaining rows of pixels work as a primary storage device for spectral information as a function of time through a line-shifting process.

16. Security system for authenticating a luminescent probe marking (M-P), comprising:

a device according to one of claims 8 to 14,

at least one reference sample (7-R) comprising at least one luminescent reference marking (M-R) for measuring reference intensity values (V_R1-V_Rn) of emission intensity (I) at time intervals (t₁-t_n) for at least one wavelength of the emission radiation (E) of said luminescent reference marking (M-R) and

at least one probe sample (7-P) comprising at least one luminescent probe marking (M-P) for measuring probe intensity values (V_P1-V_Pn) of emission intensity (I) at time intervals (t₁-t_n) for at least one wavelength of the emission radiation (E) of said luminescent probe marking (M-P).

17. Security system according to claim 15, characterized in that at least one of said probe sample (7-P) is part of an ink and/or coating composition of an article (7) to be authenticated.

18. Security system according to claim 15, characterized in that at least one of said probe samples (7-P) is contained in a bulk material of an article (7) to be authenticated.

9. Device for authenticating a luminescent reference marking (M-R), comprising:

at least one detector (4, 41, 42, 4b) for measuring reference intensity values (V_R1-V_Rn) of emission intensity (I) from emission radiation (E) of said luminescent reference marking (M-R) in response to at least one excitation pulse (P) generated by at least one excitation source (3, 31-36) at time intervals (t₁-t_n) and

at least one processor (1) for forming reference intensity-versus-time emission function of said reference intensity values (V_R1-V_Rn).

11. Device according to one of claimc 8 to 10, characterized in that it comprises said at least one excitation source (3, 31-36).