Information encoding on surfaces by varying spectral emissivity

• US 7,044,386 B2
• Filed: 02/01/2003
• Issued: 05/16/2006
• Est. Priority Date: 02/05/2002
• Status: Expired due to Fees

• Current Assignee: William Berson
• Original Assignee: William Berson
• Inventors: Berson, William
• Primary Examiner(s): Fureman, Jared J.
• Application Number:
  US10/355,670
• Publication Number:
  US 20030146288A1
• Time in Patent Office: 1,200 Days
• Field of Search: 235/454, 235/462.01, 235/462.04, 235/468, 235/469, 235/491, 235/494
• US Class Current: 235/491
• CPC Class Codes: G06K 1/123 for colour code marks
• CPC Class Codes: G06K 19/06028 using bar codes
• CPC Class Codes: G06K 2019/06225 using wavelength selection, e.g. colour code
• CPC Class Codes: G06K 2019/06271 Relief-type marking
• CPC Class Codes: G06K 7/12 using a selected wavelength, e.g. to sense red marks and ignore blue marks

Abstract

A method for applying surface modifications in at least two patterns that differ in spectral emissivity by known amounts. The patterns form an information-encoding sequence of transitions of differential emissivity along a scan path over the patterns, that encodes a set of information. This information is decoded by a scanner sensitive to emissivity in the given portion of the electromagnetic spectrum, and sensitive to transitions in emissivity of the known amounts, when scanned along the scan path, combined with knowledge of the expected emissivity values of the patterns. This provides secure informational marking of articles and documents, including mail. The patterns may be visible, or hidden, but the emissivity values are not duplicated by standard office equipment, so authenticity of the patterns can be determined using the special emissivity scanner.

Claims

1. A method for encoding information on surfaces, comprising:

providing a surface;

applying to the surface a first pattern using a first surface modification that emits energy based on a first intrinsic emissivity value at a given temperature; and

applying to the surface a second pattern using a second surface modification that emits energy based on a second intrinsic emissivity value that differs from the first intrinsic emissivity value at the given temperature;

the first and second patterns forming an information-encoding sequence of transitions of differential emissivity along a scan path over the patterns that encodes a given set of information;

whereby an emissivity sensor that is sensitive to transitions in intrinsic emissivity, when scanned along the scan path over the patterns, will detect emissivity transitions that encode the given set of information regardless of whether any light is present.

2. The method of claim 1, wherein:

the first surface modification has a given appearance based on light reflection and absorption in the visible spectrum;

the second surface modification has an appearance based on light reflection and absorption in the visible spectrum that is substantially the same as the given appearance of the first surface modification; and

the first and second surface modifications are applied in a combined pattern that does not reveal the given set of information in the visible spectrum.

3. The method of claim 1, wherein at least one of the transitions of differential emissivity is at least 0.05.

4. The method of claim 1, wherein:

the first surface modification is a first ink; and

the second surface modification is a second ink.

5. The method of claim 1, wherein:

the first surface modification is a first surface texture; and

the second surface modification is a second surface texture, the first and second surface textures being different.

6. The method of claim 5, wherein the first and second surface modifications are created by embossing the surface with an electromechanical dot matrix printer.

7. The method of claim 5, wherein the first and second surface modifications are created by applying different dot density patterns on the surface by raised printing.

8. The method of claim 1, further comprising:

scanning the patterns using a scanner that is sensitive to transitions in intrinsic emissivity to detect emissivity transitions; and

decoding the emissivity transitions into the given set of information.

9. A method for encoding information on surfaces, comprising:

providing a surface;

providing a first ink that emits energy based on a first intrinsic emissivity value at a given temperature;

providing a second ink that emits energy based on a second intrinsic emissivity value that differs from the first intrinsic emissivity value at the given temperature;

applying to the surface a first pattern using the first ink; and

applying to the surface a second pattern using the second ink, the first and second patterns forming an information-encoding sequence of transitions of differential emissivity along a scan path over the patterns, that encodes a given set of information;

whereby an emissivity sensor that is sensitive to the given portion of the electromagnetic spectrum, and sensitive to transitions in intrinsic emissivity, when scanned along the scan path over the patterns, will detect emissivity transitions that encode the given set of information regardless of whether any light is present.

10. The method of claim 9, wherein:

the first and second inks have substantially the same appearance in the visible spectrum; and

the first and second inks are applied in a combined pattern that does not reveal the given set of information in the visible spectrum.

11. The method of claim 9, further comprising:

scanning the patterns using a scanner that is sensitive to the given portion of the electromagnetic spectrum, and is sensitive to transitions in intrinsic emissivity to detect emissivity transitions; and

decoding the emissivity transitions into the given set of information.

12. The method of claim 9, further comprising:

providing at least one additional ink that emits energy based on an intrinsic emissivity value wherein, each of the first, second, and the at least one additional ink has a different intrinsic emissivity value;

applying to the surface at least one additional pattern using the at least one additional ink, the patterns forming an information-encoding sequence of transitions of differential emissivity along a scan path over the patterns that encodes a given set of information.

13. A method for encoding information on surfaces, comprising:

providing a surface that emits energy based on a first intrinsic emissivity value at a given temperature;

applying a first texture to the surface in a first pattern that emits energy based on a second intrinsic emissivity value at the given temperature; and

applying a second texture to the surface in a second pattern that emits energy based on a third intrinsic emissivity value that differs from both the first and second intrinsic emissivity values at the given temperature, the second and third patterns forming an information-encoding sequence of transitions of differential emissivity along a scan path over the patterns that encodes a given set of information;

whereby an emissivity sensor that is sensitive to the given portion of the electromagnetic spectrum, and sensitive to transitions in intrinsic emissivity, when scanned along the scan path over the patterns, will detect emissivity transitions that encode the given set of information regardless of whether any light is present.

14. The method of claim 13, further comprising:

scanning the patterns using a scanner that is sensitive to transitions in emissivity to detect emissivity transitions; and

decoding the given set of information.

15. A method for encoding information on surfaces, comprising:

providing a surface that emits energy based on a first intrinsic emissivity value at a given temperature;

applying to the surface a first surface modification that emits energy based on a second intrinsic emissivity value that differs from the first intrinsic emissivity value at the given temperature; and

applying to the surface a second surface modification which emits energy based on a third intrinsic emissivity value that differs from at least one of the first and second intrinsic emissivity values at the given temperature; and

arranging the first surface modification in at least one pattern that forms an information-encoding sequence of transitions of differential emissivity, wherein the transitions of differential emissivity encode a first given set of information regardless of whether any light is present.

16. The method of claim 15, wherein:

the second surface modification is arranged in at least one pattern that forms a detectable information-encoding sequence of transitions of differential emissivity that encodes a second given set of information;

whereby an emissivity detector that is sensitive to transitions of differential emissivity detects emissivity transitions to decode the second given set of information.

17. The method of claim 15, wherein:

the first surface modification has a given appearance based on light reflection and absorption in the visible spectrum;

the second surface modification has an appearance based on light reflection and absorption in the visible spectrum that is substantially the same as the given appearance of the first surface modification; and

the first and second surface modifications are applied in a combined pattern that does not reveal at least one of the given sets of information in the visible spectrum.