US 5,627,663 A · Secure optical identification method and means

Abstract

In a preferred embodiment, a method of providing secure identification for an article, including: providing on the article a diffraction grating strip including a pattern of a series of diffraction grating elements, each the diffraction grating element to diffract light, from a light source, in one of at least three selected different planes; serially illuminating the diffraction grating elements, detecting changes in plane of diffracted light as the diffraction grating elements are serially illuminated, and generating first information representative of the changes in plane; storing the first information representative of the changes in plane; subsequently, serially illuminating the diffraction grating elements, detecting changes in plane of diffracted light as the diffraction grating elements are serially illuminated, and generating second information representative of the changes in plane; and then, comparing the first and second information to determine the authenticity or not of the article. In a further aspect of the invention, a coded pattern is placed on the diffraction grating strip, with one of the coded pattern and the pattern of diffraction grating elements precessing with respect to the other and the coded pattern is read, stored, and compared as part of the first and second information, as above.

Claims14

Dependent claims

An article for secure identification, comprising:

(a) a substrate;
(b) a diffraction grating strip disposed on said article, said diffraction grating strip comprising a pattern of a series of diffraction grating elements, each said diffraction grating element to diffract light, from a light source, in one of at least three selected different planes;
and
(c) a different coded pattern superposed on said diffraction grating strip, each repetition of one of said coded pattern and said pattern of diffraction grating elements being incrementally displaced with respect to the other of said coded pattern and said diffraction grating strip, compared with the immediately preceding repetition thereof.

1 more element

A method of providing secure identification for an article, comprising:

(a) providing on said article a diffraction grating strip comprising a pattern of a series of diffraction grating elements, each said diffraction grating element to diffract light, from a light source, in one of at least three selected different planes, and placing said diffraction grating strip on said article in a positionally random manner with respect to a physical feature of said article;;
(b) serially illuminating said diffraction grating elements, detecting transitions between changes in plane of diffracted light as said diffraction grating elements are serially illuminated, and generating first information representative of said changes in plane, said first information being generated from said transitions without the use of a clock;
(c) measuring the distance from a selected one of said diffraction grating elements to a known plane change sequence on said diffraction grating strip and including said distance in said first information;
(d) storing said first information representative of said changes in plane;
(e) subsequently, serially illuminating said diffraction grating elements, detecting transitions between changes in plane of diffracted light as said diffraction grating elements are serially illuminated, and generating second information representative of said changes in plane, said second information being generated from said transitions without the use of a clock;
(f) measuring the distance from a selected one of said diffraction grating elements to a known plane change sequence on said diffraction grating strip and including said distance in said second information;
and
(g) then, comparing said first and second information to determine the authenticity or not of said article.

5 more elements

A method of providing secure identification for an article, comprising:

(a) providing on said article a diffraction grating strip comprising a pattern of a series of diffraction grating elements, each said diffraction grating element to diffract light, from a light source, in one of at least three selected different planes;
(b) superposing a different coded pattern on said diffraction grating strip, each repetition of one of said coded pattern and said pattern of diffraction grating elements being incrementally displaced with respect to the other repetitions of said coded pattern and said diffraction grating strip, compared with the immediately preceding repetition thereof;
(c) serially illuminating said diffraction grating elements, detecting transitions between changes in plane of diffracted light as said diffraction grating elements are serially illuminated, and generating first information representative of said changes in plane, said first information being generated from said transitions without the use of a clock, and reading said coded pattern and including a representation thereof in said first information;
(d) storing said first information representative of said changes in plane;
(e) subsequently, serially illuminating said diffraction grating elements, detecting transitions between changes in plane of diffracted light as said diffraction grating elements are serially illuminated, and generating second information representative of said changes in plane, said second information being generated from said transitions without the use of a clock, and reading said coded pattern and including a representation thereof in said second information;
and
(f) then, comparing said first and second information to determine the authenticity or not of said article.

4 more elements

Dependencies are inferred from the claim text.

Secure optical identification method and means

Life of this patent

Secure optical identification method and means

Life of this patent

Abstract

Claims14